研究者データベース

迫田 義博(サコダ ヨシヒロ)
獣医学研究院 獣医学部門 病原制御学分野
教授

基本情報

所属

  • 獣医学研究院 獣医学部門 病原制御学分野

職名

  • 教授

学位

  • 博士(獣医学)(北海道大学)

論文上での記載著者名

  • Yoshihiro, Sakoda

ホームページURL

科研費研究者番号

  • 40333637

J-Global ID

研究分野

  • ライフサイエンス / 獣医学 / 微生物学
  • ライフサイエンス / 獣医学 / 微生物学
  • ライフサイエンス / 獣医学 / 微生物学
  • ライフサイエンス / ウイルス学

職歴

  • 2014年04月 - 現在 北海道大学 大学院獣医学研究院 教授
  • 2005年 - 2014年03月 北海道大学 大学院獣医学研究科 准教授
  • 2001年 - 2005年 北海道大学 大学院獣医学研究科 助教

学歴

  •         - 1994年   北海道大学   獣医学部   獣医
  •         - 1994年   北海道大学

所属学協会

  • 日本家畜衛生学会   日本ウイルス学会   日本獣医学会   

研究活動情報

論文

  • Llilianne Ganges, Helen R Crooke, Jose Alejandro Bohórquez, Alexander Postel, Yoshihiro Sakoda, Paul Becher, Nicolas Ruggli
    Virus research 289 198151 - 198151 2020年11月 [査読有り][通常論文]
     
    Classical swine fever (CSF) is among the most relevant viral epizootic diseases of swine. Due to its severe economic impact, CSF is notifiable to the world organisation for animal health. Strict control policies, including systematic stamping out of infected herds with and without vaccination, have permitted regional virus eradication. Nevertheless, CSF virus (CSFV) persists in certain areas of the world and has re-emerged regularly. This review summarizes the basic established knowledge in the field and provides a comprehensive and updated overview of the recent advances in fundamental CSFV research, diagnostics and vaccine development. It covers the latest discoveries on the genetic diversity of pestiviruses, with implications for taxonomy, the progress in understanding disease pathogenesis, immunity against acute and persistent infections, and the recent findings in virus-host interactions and virulence determinants. We also review the progress and pitfalls in the improvement of diagnostic tools and the challenges in the development of modern and efficacious marker vaccines compatible with serological tests for disease surveillance. Finally, we highlight the gaps that require research efforts in the future.
  • Marina Gulyaeva, Falk Huettmann, Alexander Shestopalov, Masatoshi Okamatsu, Keita Matsuno, Duc-Huy Chu, Yoshihiro Sakoda, Alexandra Glushchenko, Elaina Milton, Eric Bortz
    Scientific reports 10 1 16817 - 16817 2020年10月08日 [査読有り][通常論文]
     
    Avian Influenza (AI) is a complex but still poorly understood disease; specifically when it comes to reservoirs, co-infections, connectedness and wider landscape perspectives. Low pathogenic (Low-path LP) AI in chickens caused by less virulent strains of AI viruses (AIVs)-when compared with highly pathogenic AIVs (HPAIVs)-are not even well-described yet or known how they contribute to wider AI and immune system issues. Co-circulation of LPAIVs with HPAIVs suggests their interactions in their ecological aspects. Here we show for the Pacific Rim an international approach how to data mine and model-predict LP AI and its ecological niche with machine learning and open access data sets and geographic information systems (GIS) on a 5 km pixel size for best-possible inference. This is based on the best-available data on the issue (~ 40,827 records of lab-analyzed field data from Japan, Russia, Vietnam, Mongolia, Alaska and Influenza Research Database (IRD) and U.S. Department of Agriculture (USDA) database sets, as well as 19 GIS data layers). We sampled 157 hosts and 110 low-path AIVs with 32 species as drivers. The prevalence across low-path AIV subtypes is dominated by Muscovy ducks, Mallards, Whistling Swans and gulls also emphasizing industrial impacts for the human-dominated wildlife contact zone. This investigation sets a good precedent for the study of reservoirs, big data mining, predictions and subsequent outbreaks of HPAI and other pandemics.
  • Ankhanbaatar Ulaankhuu, Enkhbold Bazarragchaa, Masatoshi Okamatsu, Takahiro Hiono, Khishgee Bodisaikhan, Tsolmon Amartuvshin, Jargalsaikhan Tserenjav, Tsogtbaatar Urangoo, Khanui Buyantogtokh, Keita Matsuno, Takanari Hattori, Tatsunari Kondoh, Masahiro Sato, Yoshihiro Takadate, Shiho Torii, Mao Isono, Kosuke Okuya, Takeshi Saito, Nodoka Kasajima, Yurie Kida, Junki Maruyama, Manabu Igarashi, Ayato Takada, Hiroshi Kida, Damdinjav Batchuluun, Yoshihiro Sakoda
    Virus genes 56 4 472 - 479 2020年08月 [査読有り][通常論文]
     
    The circulation of highly pathogenic avian influenza viruses (HPAIVs) of various subtypes (e.g., H5N1, H5N6, H5N8, and H7N9) in poultry remains a global concern for animal and public health. Migratory waterfowls play important roles in the transmission of these viruses across countries. To monitor virus spread by wild birds, active surveillance for avian influenza in migratory waterfowl was conducted in Mongolia from 2015 to 2019. In total, 5000 fecal samples were collected from lakesides in central Mongolia, and 167 influenza A viruses were isolated. Two H5N3, four H7N3, and two H7N7 viruses were characterized in this study. The amino acid sequence at hemagglutinin (HA) cleavage site of those isolates suggested low pathogenicity in chickens. Phylogenetic analysis revealed that all H5 and H7 viruses were closely related to recent H5 and H7 low pathogenic avian influenza viruses (LPAIVs) isolated from wild birds in Asia and Europe. Antigenicity of H7Nx was similar to those of typical non-pathogenic avian influenza viruses (AIVs). While HPAIVs or A/Anhui/1/2013 (H7N9)-related LPAIVs were not detected in migratory waterfowl in Mongolia, sporadic introductions of AIVs including H5 and H7 viruses into Mongolia through the wild bird migration were identified. Thus, continued monitoring of H5 and H7 AIVs in both domestic and wild birds is needed for the early detection of HPAIVs spread into the country.
  • Hirotaka Hayashi, Masatoshi Okamatsu, Honami Ogasawara, Naoko Tsugawa, Norikazu Isoda, Keita Matsuno, Yoshihiro Sakoda
    Nutrients 12 7 2020年07月05日 [査読有り][通常論文]
     
    Vitamin D is a fat-soluble vitamin that is metabolized by the liver into 25-hydroxyvitamin D [25(OH)D] and then by the kidney into 1,25-dihydroxyvitamin D [1,25(OH)2D], which activates the vitamin D receptor expressed in various cells, including immune cells, for an overall immunostimulatory effect. Here, to investigate whether oral supplementation of 25-hydroxyvitamin D3 [25(OH)D3], a major form of vitamin D metabolite 25(OH)D, has a prophylactic effect on influenza A virus infection, mice were fed a diet containing a high dose of 25(OH)D3 and were challenged with the influenza virus. In the lungs of 25(OH)D3-fed mice, the viral titers were significantly lower than in the lungs of standardly fed mice. Additionally, the proinflammatory cytokines IL-5 and IFN-γ were significantly downregulated after viral infection in 25(OH)D3-fed mice, while anti-inflammatory cytokines were not significantly upregulated. These results indicate that 25(OH)D3 suppresses the production of inflammatory cytokines and reduces virus replication and clinical manifestations of influenza virus infection in a mouse model.
  • Cong Thanh Nguyen, Saori Suzuki, Yasushi Itoh, Hirohito Ishigaki, Misako Nakayama, Kaori Hayashi, Keita Matsuno, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Kazumasa Ogasawara
    Antimicrobial agents and chemotherapy 64 7 2020年06月23日 [査読有り][通常論文]
     
    Attention has been paid to H5N6 highly pathogenic avian influenza virus (HPAIV) because of its heavy burden on the poultry industry and human mortality. Since an influenza A virus carrying N6 neuraminidase (NA) has never spread in humans, the potential for H5N6 HPAIV to cause disease in humans and the efficacy of antiviral drugs against the virus need to be urgently assessed. We used nonhuman primates to elucidate the pathogenesis of H5N6 HPAIV as well as to determine the efficacy of antiviral drugs against the virus. H5N6 HPAIV infection led to high fever in cynomolgus macaques. The lung injury caused by the virus was severe, with diffuse alveolar damage and neutrophil infiltration. In addition, an increase in interferon alpha (IFN-α) showed an inverse correlation with virus titers during the infection process. Oseltamivir was effective for reducing H5N6 HPAIV propagation, and continuous treatment with peramivir reduced virus propagation and the severity of symptoms in the early stage. This study also showed pathologically severe lung injury states in cynomolgus macaques infected with H5N6 HPAIV, even in those that received early antiviral drug treatments, indicating the need for close monitoring and further studies on virus pathogenicity and new antiviral therapies.
  • Saori Suzuki, Shintaro Shichinohe, Yasushi Itoh, Misako Nakayama, Hirohito Ishigaki, Yuya Mori, Ayako Ogata-Nakahara, Cong Thanh Nguyen, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Kazumasa Ogasawara
    Antiviral research 178 104790 - 104790 2020年06月 [査読有り][通常論文]
     
    Human cases of H7N9 influenza A virus infection have been increasing since 2013. The first choice of treatment for influenza is neuraminidase (NA) inhibitors (NAIs), but there is a concern that NAI-resistant viruses are selected in the presence of NAIs. In our previous study, an H7N9 virus carrying AA substitution of threonine (T) for isoleucine (I) at residue 222 in NA (NA222T, N2 numbering) and an H7N9 virus carrying AA substitution of lysine (K) for arginine (R) at residue 292 in NA (NA292K, N2 numbering) were found in different macaques that had been infected with A/Anhui/1/2013 (H7N9) and treated with NAIs. In the present study, the variant with NA292K showed not only resistance to NAIs but also lower replication activity in MDCK cells than did the virus with wild-type NA, whereas the variant with NA222T, which was less resistant to NAIs, showed replication activity similar to that of the wild-type virus. Next, we examined the pathogenicity of these H7N9 NAI-resistant viruses in macaques. The variants caused clinical signs similar to those caused by the wild-type virus with similar replication potency. However, the virus with NA292K was replaced within 7 days by that with NA292R (same as the wild-type) in nasal samples from macaques infected with the virus with NA292K, i.e. the so-called revertant (wild-type virus) became dominant in the population in the absence of an NAI. These results suggest that the clinical signs observed in macaques infected with the NA292K virus are caused by the NA292K virus and the NA292R virus and that the virus with NA292K may not replicate continuously in the upper respiratory tract of patients without treatment as effectively as the wild-type virus.
  • Lam Thanh Nguyen, Mark A Stevenson, Simon M Firestone, Leslie D Sims, Duc Huy Chu, Long Van Nguyen, Tien Ngoc Nguyen, Kien Trung Le, Norikazu Isoda, Keita Matsuno, Masatoshi Okamatsu, Hiroshi Kida, Yoshihiro Sakoda
    Preventive veterinary medicine 178 104678 - 104678 2020年05月 [査読有り][通常論文]
     
    The aim of this study was to describe the spatiotemporal distribution of H5 HPAI outbreak reports for the period 2014-2017 and to identify factors associated with H5 HPAI outbreak reports. Throughout the study period, a total of 139 outbreaks of H5 HPAI in poultry were reported, due to either H5N1 (96 outbreaks) or H5N6 (43 outbreaks) subtype viruses. H5N1 HPAI outbreaks occurred in all areas of Vietnam while H5N6 HPAI outbreaks were only reported in the northern and central provinces. We counted the number of H5N1 and H5N6 outbreak report-positive districts per province over the four-year study period and calculated the provincial-level standardized morbidity ratio for H5N1 and H5N6 outbreak reports as the observed number of positive districts divided by the expected number. A mixed-effects, zero-inflated Poisson regression model was developed to identify risk factors for outbreak reports of each H5N1 and H5N6 subtype virus. Spatially correlated and uncorrelated random effects terms were included in this model to identify areas of the country where outbreak reports occurred after known risk factors had been accounted-for. The presence of an outbreak report in a province in the previous 6-12 months increased the provincial level H5N1 outbreak report risk by a factor of 2.42 (95% Bayesian credible interval [CrI] 1.27-4.60) while 1000 bird increases in the density of chickens decreased provincial level H5N6 outbreak report risk by a factor of 0.65 (95% CrI 0.38 to 0.97). We document distinctly different patterns in the spatial and temporal distribution of H5N1 and H5N6 outbreak reports. Most of the variation in H5N1 report risk was accounted-for by the fixed effects included in the zero-inflated Poisson model. In contrast, the amount of unaccounted-for risk in the H5N6 model was substantially greater than the H5N1 model. For H5N6 we recommend that targeted investigations should be carried out in provinces with relatively large spatially correlated random effect terms to identify likely determinants of disease. Similarly, investigations should be carried out in provinces with relatively low spatially correlated random effect terms to identify protective factors for disease and/or reasons for failure to report.
  • Yuto Kikutani, Masatoshi Okamatsu, Shoko Nishihara, Sayaka Takase-Yoden, Takahiro Hiono, Robert P de Vries, Ryan McBride, Keita Matsuno, Hiroshi Kida, Yoshihiro Sakoda
    Microbiology and immunology 64 4 304 - 312 2020年04月 [査読有り][通常論文]
     
    Avian influenza viruses (AIVs) recognize sialic acid linked α2,3 to galactose (SAα2,3Gal) glycans as receptors. In this study, the interactions between hemagglutinins (HAs) of AIVs and sulfated SAα2,3Gal glycans were analyzed to clarify the molecular basis of interspecies transmission of AIVs from ducks to chickens. It was revealed that E190V and N192D substitutions of the HA increased the recovery of viruses derived from an H6 duck virus isolate, A/duck/Hong Kong/960/1980 (H6N2), in chickens. Recombinant HAs from an H6 chicken virus, A/chicken/Tainan/V156/1999 (H6N1), bound to sulfated SAα2,3Gal glycans, whereas the HAs from an H6 duck virus did not. Binding preference of mutant HAs revealed that an E190V substitution is critical for the recognition of sulfated SAα2,3Gal glycans. These results suggest that the binding of the HA from H6 AIVs to sulfated SAα2,3Gal glycans explains a part of mechanisms of interspecies transmission of AIVs from ducks to chickens.
  • Madoka Tetsuo, Keita Matsuno, Tomokazu Tamura, Takasuke Fukuhara, Taksoo Kim, Masatoshi Okamatsu, Norbert Tautz, Yoshiharu Matsuura, Yoshihiro Sakoda
    Pathogens (Basel, Switzerland) 9 3 2020年03月04日 [査読有り][通常論文]
     
    A serum neutralization test (SNT) is an essential method for the serological diagnosis of pestivirus infections, including classical swine fever, because of the cross reactivity of antibodies against pestiviruses and the non-quantitative properties of antibodies in an enzyme-linked immunosorbent assay. In conventional SNTs, an immunoperoxidase assay or observation of cytopathic effect after incubation for 3 to 7 days is needed to determine the SNT titer, which requires labor-intensive or time-consuming procedures. Therefore, a new SNT, based on the luciferase system and using classical swine fever virus, bovine viral diarrhea virus, and border disease virus possessing the 11-amino-acid subunit derived from NanoLuc luciferase was developed and evaluated; this approach enabled the rapid and easy determination of the SNT titer using a luminometer. In the new method, SNT titers can be determined tentatively at 2 days post-infection (dpi) and are comparable to those obtained by conventional SNTs at 3 or 4 dpi. In conclusion, the luciferase-based SNT can replace conventional SNTs as a high-throughput antibody test for pestivirus infections.
  • Kien Trung Le, Masatoshi Okamatsu, Lam Thanh Nguyen, Keita Matsuno, Duc-Huy Chu, Tien Ngoc Tien, Tung Thanh Le, Hiroshi Kida, Yoshihiro Sakoda
    Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases 78 104117 - 104117 2020年03月 [査読有り][通常論文]
     
    During the annual surveillance of avian influenza viruses (AIVs) in Vietnam in 2018, three H7N7 AIV isolates were identified in domestic ducks in a single flock in Vinh Long province. The present study is the first documented report of H7N7 virus isolates in Vietnam and aimed to characterize these viruses, both genetically and antigenically. Deduced amino acid sequences for the hemagglutinins (HAs) indicated a low pathogenicity of these viruses in chickens. Phylogenetic analysis revealed that the H7 HA genes of these isolates were closely related to each other and belonged to the European-Asian sublineage, together with those of H7N3 viruses isolated from ducks in Cambodia during 2017. They were not genetically related to those of Chinese H7N9 or H7N1 viruses that were previously detected in Vietnam during 2012. Interestingly, the M genes of the two H7N7 virus isolates were phylogenetically classified into distinct groups, suggesting an ongoing reassortment event in domestic ducks because they were isolated from the same flock. These H7N7 viruses exhibited somewhat different antigenic characteristics compared with other representative H7 low pathogenic AIVs. Surprisingly, the antigenicity of Vietnamese H7N7 viruses is similar to Chinese H7N9 highly pathogenic AIV. The findings of this study suggest that H7N7 viruses may be undergoing reassortment and antigenic diversification in poultry flocks in Vietnam. The silent spread of Vietnamese H7N7 viruses in chickens may lead to acquire high pathogenicity in chickens although the zoonotic potential of the viruses seems to be low since these viruses retain typical avian-specific motifs in the receptor-binding site in the HA and there is no mutation related to mammalian adaptation in PB2 gene. Thus, these results highlight the need for continuous and intensive surveillance of avian influenza in Vietnam, targeting not only highly pathogenic AIVs but also low pathogenic viruses.
  • Norikazu Isoda, Kairi Baba, Satoshi Ito, Mitsugi Ito, Yoshihiro Sakoda, Kohei Makita
    Pathogens (Basel, Switzerland) 9 2 2020年02月13日 [査読有り][通常論文]
     
    The prolongation of the classic swine fever (CSF) outbreak in Japan in 2018 was highly associated with the persistence and widespread of the CSF virus (CSFV) in the wild boar population. To investigate the dynamics of the CSF outbreak in wild boar, spatiotemporal analyses were performed. The positive rate of CSFV in wild boar fluctuated dramatically from March to June 2019, but finally stabilized at approximately 10%. The Euclidean distance from the initial CSF notified farm to the farthest infected wild boar of the day constantly increased over time since the initial outbreak except in the cases reported from Gunma and Saitama prefectures. The two-month-period prevalence, estimated using integrated nested Laplace approximation, reached >80% in half of the infected areas in March-April 2019. The area affected continued to expand despite the period prevalence decreasing up to October 2019. A large difference in the shapes of standard deviational ellipses and in the location of their centroids when including or excluding cases in Gunma and Saitama prefectures indicates that infections there were unlikely to have been caused simply by wild boar activities, and anthropogenic factors were likely involved. The emergence of concurrent space-time clusters in these areas after July 2019 indicated that CSF outbreaks were scattered by this point in time. The results of this epidemiological analysis help explain the dynamics of the spread of CSF and will aid in the implementation of control measures, including bait vaccination.
  • Yukari Itakura, Keita Matsuno, Asako Ito, Markus Gerber, Matthias Liniger, Yuri Fujimoto, Tomokazu Tamura, Ken-Ichiro Kameyama, Masatoshi Okamatsu, Nicolas Ruggli, Hiroshi Kida, Yoshihiro Sakoda
    Virus research 276 197809 - 197809 2020年01月15日 [査読有り][通常論文]
     
    Classical swine fever viruses (CSFVs) do typically not show cytopathic effect (CPE) in cell culture, while some strains such as vaccine strain the GPE- induce CPE in the swine kidney-derived CPK-NS cell line cultured in serum-free medium. These latter strains commonly lack Npro-mediated inhibition of type-I interferon (IFN) induction. In order to explore the molecular mechanisms of GPE--induced CPE, we analyzed the cellular pathways involved. In CPK-NS cells infected with the attenuated-vaccine-derived vGPE- strain, both, apoptosis and necroptosis were induced. Necroptosis was type-I IFN-dependent and critical for visible CPE. In contrast, the parental virulent vALD-A76 strain did not induce any of these pathways nor CPE. We used reverse genetics to investigate which viral factors regulate these cell-death pathways. Interestingly, a mutant vGPE- in which the Npro function was restored to inhibit type-I IFN induction did not induce necroptosis nor CPE but still induced apoptosis, while an Npro-mutant vALD-A76 incapable of inhibiting type-I IFN production induced necroptosis and CPE. Although Erns of CSFV is reportedly involved in controlling apoptosis, apoptosis induction by vGPE- or apoptosis inhibition by vALD-A76 were independent of the unique amino acid difference found in Erns of these two strains. Altogether, these results demonstrate that type-I IFN-dependent necroptosis related to non-functional Npro is the main mechanism for CPE induction by vGPE-, and that viral factor(s) other than Erns may induce or inhibit apoptosis in vGPE- or vALD-A76 infected CPK-NS cells, respectively.
  • Augustin T Twabela, Masatoshi Okamatsu, Georges Mbuyi Tshilenge, Serge Mpiana, Justin Masumu, Lam Thanh Nguyen, Keita Matsuno, Isabella Monne, Bianca Zecchin, Yoshihiro Sakoda
    Archives of virology 165 1 87 - 96 2020年01月 [査読有り][通常論文]
     
    In May 2017, high mortality of chickens and Muscovy ducks due to the H5N8 highly pathogenic avian influenza virus (HPAIV) was reported in the Democratic Republic of Congo (DR Congo). In this study, we assessed the molecular, antigenic, and pathogenic features in poultry of the H5N8 HPAIV from the 2017 Congolese outbreaks. Phylogenetic analysis of the eight viral gene segments revealed that all 12 DR Congo isolates clustered in clade 2.3.4.4B together with other H5N8 HPAIVs isolated in Africa and Eurasia, suggesting a possible common origin of these viruses. Antigenically, a slight difference was observed between the Congolese isolates and a representative virus from group C in the same clade. After intranasal inoculation with a representative DR Congo virus, high pathogenicity was observed in chickens and Muscovy ducks but not in Pekin ducks. Viral replication was higher in chickens than in Muscovy duck and Pekin duck organs; however, neurotropism was pronounced in Muscovy ducks. Our data confirmed the high pathogenicity of the DR Congo virus in chickens and Muscovy ducks, as observed in the field. National awareness and strengthening surveillance in the region are needed to better control HPAIVs.
  • Mai Shiokawa, Tsutomu Omatsu, Yukie Katayama, Kaoru Nishine, Yuri Fujimoto, Shiori Uchiyama, Ken-Ichiro Kameyama, Makoto Nagai, Tetsuya Mizutani, Yoshihiro Sakoda, Akio Fukusho, Hiroshi Aoki
    Virology 538 97 - 110 2019年12月 [査読有り][通常論文]
     
    Our previous study reported that persistently infected (PI) cattle of bovine viral diarrhea virus (BVDV) have co-infected with BVDV/END- and /END+ that promote and inhibit host's type-I interferon (IFN) production, respectively. However, the relationship between co-infection of immunologically distinct BVDVs and persistent infection as well as the biological significance of END- viruses remains unknown. Experiments using cultured cells revealed that END+ virus, which is unable to propagate in situations where the host's immune response is induced by IFN-α addition, is able to propagate under those conditions when co-infecting with END- virus. These results indicate that BVDV/END- can coexist with BVDV/END+ and that co-infection with END- viruses supports the propagation of END+ viruses. Our in vitro experiments strongly suggest that co-infection with END- virus is involved in the maintenance of persistent infection of BVDV.
  • Tomokazu Tamura, Manabu Igarashi, Bazarragchaa Enkhbold, Tatsuya Suzuki, Masatoshi Okamatsu, Chikako Ono, Hiroyuki Mori, Takuma Izumi, Asuka Sato, Yuzy Fauzyah, Toru Okamoto, Yoshihiro Sakoda, Takasuke Fukuhara, Yoshiharu Matsuura
    Journal of virology 93 22 2019年11月15日 [査読有り][通常論文]
     
    Recombinant viruses possessing reporter proteins have been generated for virus research. In the case of the family Flaviviridae, we recently generated recombinant viruses, including the hepatitis C virus of the genus Hepacivirus, Japanese encephalitis virus (JEV) of the genus Flavivirus, and bovine viral diarrhea virus of the genus Pestivirus; all three viruses possess an 11-amino-acid subunit derived from NanoLuc luciferase (HiBiT). Here, we further developed the recombinant viruses and investigated their utility in vivo Recombinant viruses harboring HiBiT in the E, NS1, or NS3 protein constructed based on the predicted secondary structure, solvent-accessible surface area, and root mean square fluctuation of the proteins exhibited comparable replication to that of the wild-type virus in vitro The recombinant JEV carrying HiBiT in the NS1 protein exhibited propagation in mice comparable to that of the parental virus, and propagation of the recombinant was monitored by the luciferase activity. In addition, the recombinants of classical swine fever virus (CSFV) possessing HiBiT in the Erns or E2 protein also showed propagation comparable to that of the wild-type virus. The recombinant CSFV carrying HiBiT in Erns exhibited similar replication to the parental CSFV in pigs, and detection of viral propagation of this recombinant by luciferase activity was higher than that by quantitative PCR (qPCR). Taken together, these results demonstrated that the reporter Flaviviridae viruses generated herein are powerful tools for elucidating the viral life cycle and pathogeneses and provide a robust platform for the development of novel antivirals.IMPORTANCEIn vivo applications of reporter viruses are necessary to understand viral pathogenesis and provide a robust platform for antiviral development. In developing such applications, determination of an ideal locus to accommodate foreign genes is important, because insertion of foreign genes into irrelevant loci can disrupt the protein functions required for viral replication. Here, we investigated the criteria to determine ideal insertion sites of foreign genes from the protein structure of viral proteins. The recombinant viruses generated by our criteria exhibited propagation comparable to that of parental viruses in vivo Our proteomic approach based on the flexibility profile of viral proteins may provide a useful tool for constructing reporter viruses, including Flaviviridae viruses.
  • Hajake T, Matsuno K, M Kasumba D, Oda H, Kobayashi M, Miyata N, Shinji M, Kogure A, Kasajima N, Okamatsu M, Sakoda Y, Kato H, Fujita T
    International immunology 31 12 811 - 821 2019年11月08日 [査読有り][通常論文]
     
    Double-stranded RNA (dsRNA) is well characterized as an inducer of anti-viral interferon responses. We previously reported that dsRNA extracted from a specific edible plant possesses an immune-modulating capacity to confer, in mice, resistance against respiratory viruses, including the H1N1 strain of the influenza A virus (IAV). We report here that the systemic immune-activating capacity of the plant-derived dsRNA protected mice from infection by a highly virulent H5N1 strain of the IAV. In addition, subcutaneous inoculation of the dsRNA together with the inactivated virion of the H5N1 strain of the IAV suppressed the lethality of the viral infection as compared with individual inoculation of either dsRNA or HA protein, suggesting its potential usage as a vaccination adjuvant. Moreover, intra-peritoneal inoculation of the dsRNA limited the growth of B16-F10 melanoma cells through the activation of NK cells in murine models. Taken together, this study demonstrated the systemic immune-modulating capacity of a plant-derived dsRNA and its potential for nucleic acid-based clinical applications.
  • Satoshi Ito, Cristina Jurado, Jaime Bosch, Mitsugi Ito, José Manuel Sánchez-Vizcaíno, Norikazu Isoda, Yoshihiro Sakoda
    Pathogens (Basel, Switzerland) 8 4 2019年10月24日 [査読有り][通常論文]
     
    Since September 2018, nearly 900 notifications of classical swine fever (CSF) have been reported in Gifu Prefecture (Japan) affecting domestic pig and wild boar by the end of August 2019. To determine the epidemiological characteristics of its spread, a spatio-temporal analysis was performed using actual field data on the current epidemic. The spatial study, based on standard deviational ellipses of official CSF notifications, showed that the disease likely spread to the northeast part of the prefecture. A maximum significant spatial association estimated between CSF notifications was 23 km by the multi-distance spatial cluster analysis. A space-time permutation analysis identified two significant clusters with an approximate radius of 12 and 20 km and 124 and 98 days of duration, respectively. When the area of the identified clusters was overlaid on a map of habitat quality, approximately 82% and 75% of CSF notifications, respectively, were found in areas with potential contact between pigs and wild boar. The obtained results provide information on the current CSF epidemic, which is mainly driven by wild boar cases with sporadic outbreaks on domestic pig farms. These findings will help implement control measures in Gifu Prefecture.
  • Mohammad Aref Agah, Kosuke Notsu, Heba M El-Khaiat, Genki Arikawa, Meiko Kubo, Shuya Mitoma, Tamaki Okabayashi, Hirohisa Mekata, Eslam Elhanafy, Hala El Daous, Thi Ngan Mai, Thi Huyen Nguyen, Norikazu Isoda, Yoshihiro Sakoda, Junzo Norimine, Satoshi Sekiguchi
    The Journal of veterinary medical science 81 10 1450 - 1454 2019年10月18日 [査読有り][通常論文]
     
    Bovine viral diarrhea virus (BVDV) footprint has spread across the globe and is responsible for one of the most economically important diseases in cattle. In Japan, some regional surveillance and preventive measures to control bovine viral diarrhea (BVD) have been implemented. However, BVDV infection is poorly understood in cattle industries, and there is no systematic BVD surveillance system and control program. Kyushu is the center for raising beef cattle in Japan. Therefore, this study aimed to determine the BVDV infection using a slaughterhouse survey among beef cattle in Kyushu, Japan. A total of 1,075 blood samples were collected at two regional slaughterhouses in Miyazaki prefecture from December 2015 to June 2016. Antigen ELISA was used for detection of BVDV antigen in blood samples. Two samples showed positive results (2/1,075; 0.18%). BVDV RNA was extracted from positive blood samples; the sequence was determined and analyzed by the neighbor-joining method for construction of the phylogenetic tree. Phylogenetic analysis based on the 5'-UTR revealed that the two positive samples were grouped into the same subtype BVDV-1b in the BVDV-1 genotype, but the infected cattle belonged to two different farms. In conclusion, this is the first study to identify the presence of BVDV in a slaughterhouse survey in Kyushu. These findings suggest that a slaughterhouse survey is a useful tool for developing a surveillance system for monitoring infectious diseases in cattle.
  • Uyangaa Temuujin, Ariunaa Tserendorj, Jumpei Fujiki, Yoshihiro Sakoda, Erdene-Ochir Tseren-Ochir, Masatoshi Okamatsu, Keita Matsuno, Tumenjargal Sharav, Motohiro Horiuchi, Takashi Umemura, Tungalag Chultemdorj
    Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases 73 269 - 275 2019年09月 [査読有り][通常論文]
     
    Canine parvovirus type 2 (CPV-2) causes a highly contagious and fatal disease, developing into acute hemorrhagic enteritis and myocarditis, in dogs. CPV-2 has evolved, generating antigenic variants CPV-2a/2b/2c that are globally distributed. However, investigating molecular characterization of CPV-2 among dog populations in Mongolia has been limited. Herein, 42 stool samples were collected from dogs with clinical signs of infection, and conventional PCR assays were employed to detect CPV-2 in 23. Our results indicated that during 2016-2018, the new CPV-2a and 2c subtypes were detected in 34.7% of the samples, and the new CPV-2b subtype was detected in 30.4% of samples. VP2 protein sequence analysis and next-generation sequencing of the complete viral genome confirmed these antigenic types. However, sequence analysis indicated new and unreported mutations, Pro580Thr, and Tyr584His in the CPV-2c subtype. From a PCR-positive sample, CPV-2c was successfully isolated, and we performed an immunofluorescence assay for antigen detection. Additionally, we performed genetic characterization and phylogenetic analysis to investigate genetic diversity among isolates from the region, resulting in high CPV-2 genetic diversity in the Mongolian dog population. Striking similarities were also observed between sequences of the strains isolated from Mongolia and China over a similar time span.
  • Sho Hideshima, Hiroki Hayashi, Hiroshi Hinou, Shunsuke Nambuya, Shigeki Kuroiwa, Takuya Nakanishi, Toshiyuki Momma, Shin-Ichiro Nishimura, Yoshihiro Sakoda, Tetsuya Osaka
    Scientific reports 9 1 11616 - 11616 2019年08月12日 [査読有り][通常論文]
     
    Pandemic influenza, triggered by the mutation of a highly pathogenic avian influenza virus (IFV), has caused considerable damage to public health. In order to identify such pandemic IFVs, antibodies that specifically recognize viral surface proteins have been widely used. However, since the analysis of a newly discovered virus is time consuming, this delays the availability of suitable detection antibodies, making this approach unsuitable for the early identification of pandemic IFVs. Here we propose a label-free semiconductor-based biosensor functionalized with sialic-acid-containing glycans for the rapid identification of the pandemic IFVs present in biological fluids. Specific glycans are able to recognize wild-type human and avian IFVs, suggesting that they are useful in discovering pandemic IFVs at the early stages of an outbreak. We successfully demonstrated that a dual-channel integrated FET biosensing system, which were modified with 6'-sialyllactose and 3'-sialyllactose for each gate area, can directly and specifically detect human H1N1 and avian H5N1 IFV particles, respectively, present in nasal mucus. Furthermore, to examine the possibility of identifying pandemic IFVs, the signal attributed to the detection of Newcastle disease virus (NDV) particles, which was selected as a prime model of a pandemic IFV, was clearly observed from both sensing gates. Our findings suggest that the proposed glycan-immobilized sensing system could be useful in identifying new pandemic IFVs at the source of an outbreak.
  • Nguyen LT, Firestone SM, Stevenson MA, Young ND, Sims LD, Chu DH, Nguyen TN, Van Nguyen L, Thanh Le T, Van Nguyen H, Nguyen HN, Tien TN, Nguyen TD, Tran BN, Matsuno K, Okamatsu M, Kida H, Sakoda Y
    Scientific reports 9 1 7723 - 7723 2019年05月22日 [査読有り][通常論文]
     
    This study aimed to elucidate virus, host and environmental dynamics of Vietnamese H5 highly pathogenic avian influenza viruses (HPAIVs) during 2014-2017. Epidemiologically, H5 HPAIVs were frequently detected in apparently healthy domestic and Muscovy ducks and therefore these are preferred species for H5 HPAIV detection in active surveillance. Virologically, clade 2.3.2.1c and 2.3.4.4 H5 HPAIVs were predominant and exhibited distinct phylogeographic evolution. Clade 2.3.2.1c viruses clustered phylogenetically in North, Central and South regions, whilst clade 2.3.4.4 viruses only detected in North and Central regions formed small groups. These viruses underwent diverse reassortment with existence of at least 12 genotypes and retained typical avian-specific motifs. These H5 HPAIVs exhibited large antigenic distance from progenitor viruses and commercial vaccines currently used in poultry. Bayesian phylodynamic analysis inferred that clade 2.3.2.1c viruses detected during 2014-2017 were likely descended from homologous clade viruses imported to Vietnam previously and/or preexisting Chinese viruses during 2012-2013. Vietnamese clade 2.3.4.4 viruses closely shared genetic traits with contemporary foreign spillovers, suggesting that there existed multiple transboundary virus dispersals to Vietnam. This study provides insights into the evolution of Vietnamese H5 HPAIVs and highlights the necessity of strengthening control measures such as, preventive surveillance and poultry vaccination.
  • Isoda N, Asano A, Ichijo M, Ohno H, Sato K, Okamoto H, Nakao S, Kato H, Saito K, Ito N, Usui A, Takayama H, Sakoda Y
    The Journal of veterinary medical science 81 4 577 - 585 2019年04月16日 [査読有り][通常論文]
     
    Bovine viral diarrhea (BVD) is a chronic disease of cattle caused by infection with BVD virus (BVDV) and can result in economic losses within the livestock industry. In Japan, the test and culling policy is a basic control measure, and implementation of an adequate vaccination program is recommended as a national policy. In addition, optional control measures, including compulsory testing of introduced animals and bulk tank milk (BTM) testing as a mass screening method, are used in several provinces, but their efficacy has not been completely assessed. We evaluated these control measures using the scenario tree model of BVD in Japan, developed in the previous study. The model outputs indicated that compulsory testing of all introduced cattle, rather than only heifers and/or non-vaccinated cattle, was cost effective and reduced the risk of BVDV introduction due to animal movement and that BTM testing could effectively monitor most part of the cattle population. Vaccination coverage and BVDV prevalence among introduced cattle could also affect the cost effectiveness of compulsory testing of targeted cattle, particularly under low vaccination coverage or high BVDV prevalence. However, even with the implementation of a highly effective monitoring scheme for many years, BVD risk could not be eliminated; it instead converged at a very low level (0.02%). Disease models with a cost-effective output could be a powerful tool in developing a control scheme for chronic animal diseases, including BVD, with the consent of relevant stakeholders.
  • Shibata A, Harada R, Okamatsu M, Matsuno K, Arita T, Suzuki Y, Shirakura M, Odagiri T, Takemae N, Uchida Y, Saito T, Sakoda Y, Osaka H
    The Journal of veterinary medical science 81 3 444 - 448 2019年03月20日 [査読有り][通常論文]
     
    A new reassortant H7N3 avian influenza virus (AIV) was isolated from a duck meat product that was illegally taken on board a passenger flight from China to Japan in March 2018. Sequencing analysis revealed that the H7N3 isolate, A/duck/Japan/AQ-HE30-1/2018 (Dk/HE30-1) (H7N3), was a reassortant highly pathogenic avian influenza virus (HPAIV) that contained the haemagglutinin (HA) gene of Chinese H7N9 HPAIV. Dk/HE30-1 (H7N3) possessed a novel polybasic sequence motif PEVPKRRRTAR/GLF at the HA cleavage site that has never previously been reported in H7 HPAIVs. The HA antigenicity of Dk/HE30-1 (H7N3) slightly differed from that of H7N9 HPAIVs previously reported. These findings will help further our knowledge of the circulation and genetic evolution of emerging AIVs in endemic areas.
  • Taniguchi K, Ando Y, Nobori H, Toba S, Noshi T, Kobayashi M, Kawai M, Yoshida R, Sato A, Shishido T, Naito A, Matsuno K, Okamatsu M, Sakoda Y, Kida H
    Scientific reports 9 1 3466 - 3466 2019年03月05日 [査読有り][通常論文]
     
    Human infections with avian-origin influenza A(H7N9) virus represent a serious threat to global health; however, treatment options are limited. Here, we show the inhibitory effects of baloxavir acid (BXA) and its prodrug baloxavir marboxil (BXM), a first-in-class cap-dependent endonuclease inhibitor, against A(H7N9), in vitro and in vivo. In cell culture, BXA at four nanomolar concentration achieved a 1.5-2.8 log reduction in virus titers of A(H7N9), including the NA-R292K mutant virus and highly pathogenic avian influenza viruses, whereas NA inhibitors or favipiravir required approximately 20-fold or higher concentrations to achieve the same levels of reduction. A(H7N9)-specific amino acid polymorphism at position 37, implicated in BXA binding to the PA endonuclease domain, did not impact on BXA susceptibility. In mice, oral administration of BXM at 5 and 50 mg/kg twice a day for 5 days completely protected from a lethal A/Anhui/1/2013 (H7N9) challenge, and reduced virus titers more than 2-3 log in the lungs. Furthermore, the potent therapeutic effects of BXM in mice were still observed when a higher virus dose was administered or treatment was delayed up to 48 hours post infection. These findings support further investigation of BXM for A(H7N9) treatment in humans.
  • Bazarragchaa E, Okamatsu M, Ulaankhuu A, Twabela AT, Matsuno K, Kida H, Sakoda Y
    Journal of virological methods 265 121 - 125 2019年03月 [査読有り][通常論文]
     
    Rapid and accurate diagnosis of influenza virus infection is essential for quick responses for both human and animal health. The Alere™ i Influenza A&B is a novel isothermal nucleic acid amplification kit that can detect and differentiate between influenza A and B viruses in human specimens in approximately 15 min. In the present study, the performance of the Alere™ i Influenza A&B kit was evaluated for its ability to detect avian influenza virus in chickens. The kit was able to detect representative avian influenza virus strains (hemagglutinin subtypes H1-H16, including the recently isolated H5 and H7 highly pathogenic avian influenza viruses), and the detection limit of the kit for these viruses varied between 10-1.4-102.1 50% egg-infective dose per test, which is higher than the analytical sensitivity of the antigen detection immunochromatography kit ESPLINE® A INFLUENZA. In experimentally infected chickens inoculated with a highly pathogenic avian influenza virus strain A/chicken/Hokkaido/002/2016 (H5N6), viral RNA was detected in the tracheal and cloacal swabs. These results indicate that this kit has the potential to be used as a rapid screening test of influenza A virus infection in chickens.
  • Shiho Torii, Keita Matsuno, Yongjin Qiu, Akina Mori-Kajihara, Masahiro Kajihara, Ryo Nakao, Naganori Nao, Katsunori Okazaki, Mariko Sashika, Takahiro Hiono, Masatoshi Okamatsu, Yoshihiro Sakoda, Hideki Ebihara, Ayato Takada, Hirofumi Sawa
    Ticks and tick-borne diseases 10 2 328 - 335 2019年02月 [査読有り][通常論文]
     
    Recent discoveries of tick-borne pathogens have raised public health concerns on tick-borne infectious diseases and emphasize the need to assess potential risks of unrecognized tick-borne pathogens. First, to determine the existence of tick-borne phleboviruses (TBPVs), genetic surveillance of phleboviruses in ticks was conducted mainly in Hokkaido, the northernmost island in Japan from 2013 to 2015. Genes of two TBPVs, previously reported as Mukawa virus (MKWV) and a newly identified relative of MKWV, Kuriyama virus (KURV), were detected and the viruses were isolated from Ixodes persulcatus collected in Hokkaido, but not in I. persulcatus collected from other areas of Japan. These viruses were phylogenetically and antigenically similar to each other. Next, to investigate the infection of MKWV in mammals, serum samples from wildlife captured in Hokkaido from 2007 to 2011 were used for serological screening. Neutralizing antibodies against MKWV were detected in both Yezo-deer (Cervus nippon yesoensis) (2/50) and raccoons (Procyon lotor) (16/64). However, no infectious MKWV was recovered from laboratory mice in experimental infections, though viral RNAs were detected in their tissues. Thus, MKWV and KURV may maintain tick-mammalian life cycles in Hokkaido, suggesting their potential as causative agents of tick-borne diseases in mammals.
  • Hiono T, Matsuda A, Wagatsuma T, Okamatsu M, Sakoda Y, Kuno A
    Virology 527 132 - 140 2019年01月15日 [査読有り][通常論文]
     
    Glycan structures on hemagglutinin (HA) of influenza A viruses have been analyzed previously to understand their significance. However, the formerly established methods using mass spectrometry present disadvantages such as procedure complexity, sensitivity, and throughput. Our study has established a novel method for analyzing glycan profiles of HA using lectin microarray techniques. We successfully obtained glycan profiles of HA starting from 1 ml of the 106 TCID50 samples through simple antigen enrichment using optimized immunoprecipitation. The profiles were reasonably consistent with known glycan structures of HA. Next, we compared glycan profiles of the HAs prepared from chicken embryos, MDCK, Vero, and A549 cells, and demonstrated the host cell-specific HA glycan profiles. Notably, the HA from MDCK cells was α1-3 galactosylated. Our method provides a highly sensitive and simple procedure for glycan profiling of the viral glycoproteins, thereby paving way for direct glycan analyses of human- and animal-derived virions.
  • Noshi T, Kitano M, Taniguchi K, Yamamoto A, Omoto S, Baba K, Hashimoto T, Ishida K, Kushima Y, Hattori K, Kawai M, Yoshida R, Kobayashi M, Yoshinaga T, Sato A, Okamatsu M, Sakoda Y, Kida H, Shishido T, Naito A
    Antiviral research 160 109 - 117 2018年12月 [査読有り][通常論文]
     
    Cap-dependent endonuclease (CEN) resides in the PA subunit of the influenza virus and mediates the critical "cap-snatching" step of viral RNA transcription, which is considered to be a promising anti-influenza target. Here, we describe in vitro characterization of a novel CEN inhibitor, baloxavir acid (BXA), the active form of baloxavir marboxil (BXM). BXA inhibits viral RNA transcription via selective inhibition of CEN activity in enzymatic assays, and inhibits viral replication in infected cells without cytotoxicity in cytopathic effect assays. The antiviral activity of BXA is also confirmed in yield reduction assays with seasonal type A and B viruses, including neuraminidase inhibitor-resistant strains. Furthermore, BXA shows broad potency against various subtypes of influenza A viruses (H1N2, H5N1, H5N2, H5N6, H7N9 and H9N2). Additionally, serial passages of the viruses in the presence of BXA result in isolation of PA/I38T variants with reduced BXA susceptibility. Phenotypic and genotypic analyses with reverse genetics demonstrate the mechanism of BXA action via CEN inhibition in infected cells. These results reveal the in vitro characteristics of BXA and support clinical use of BXM to treat influenza.
  • Akihiro Shibata, Masatoshi Okamatsu, Riho Sumiyoshi, Keita Matsuno, Zu-Jyun Wang, Hiroshi Kida, Hiroyuki Osaka, Yoshihiro Sakoda
    Virology 524 10 - 17 2018年11月 [査読有り][通常論文]
     
    H7N9 highly and low pathogenic avian influenza viruses (HPAIV and LPAIV, respectively) have been isolated from duck meat products that were brought illegally into Japan by flight passengers in their hand luggage. These H7N9 virus isolates were phylogenetically closely related to those prevailing in China. Antigenic analysis revealed that the hemagglutinin of the H7N9 HPAIV isolate was slightly different from those of the H7N9 LPAIV and older H7 strains. These meat products contaminated with AIVs repeatedly brought into Japan lead to increased risks of poultry and public health. Continuous border disease control based on the detection and culling of infected poultry and meat products is, thus, essential for the prevention of introduction and spread of AIVs.
  • Keita Matsuno, Noriyuki Nonoue, Ayako Noda, Nodoka Kasajima, Keita Noguchi, Ai Takano, Hiroshi Shimoda, Yasuko Orba, Mieko Muramatsu, Yoshihiro Sakoda, Ayato Takada, Shinji Minami, Yumi Une, Shigeru Morikawa, Ken Maeda
    Emerging infectious diseases 24 9 1726 - 1729 2018年09月 [査読有り][通常論文]
     
    Two captive cheetahs from a zoo in Japan died of a severe fever with thrombocytopenia syndrome-like illness. Severe fever with thrombocytopenia syndrome virus, an endemic tickborne phlebovirus, was detected systemically with secretion of infectious viruses into the saliva. These cases highlight the risk for exposure of captive animals to endemic arthropodborne pathogens.
  • Zu-Jyun Wang, Yuto Kikutani, Lam Thanh Nguyen, Takahiro Hiono, Keita Matsuno, Masatoshi Okamatsu, Scott Krauss, Richard Webby, Youn-Jeong Lee, Hiroshi Kida, Yoshihiro Sakoda
    Virus genes 54 4 543 - 549 2018年08月 [査読有り][通常論文]
     
    Among 16 haemagglutinin (HA) subtypes of avian influenza viruses (AIVs), H13 AIVs have rarely been isolated in wild waterfowl. H13 AIVs cause asymptomatic infection and are maintained mainly in gull and tern populations; however, the recorded antigenic information relating to the viruses has been limited. In this study, 2 H13 AIVs, A/duck/Hokkaido/W345/2012 (H13N2) and A/duck/Hokkaido/WZ68/2012 (H13N2), isolated from the same area in the same year in our surveillance, were genetically and antigenically analyzed with 10 representative H13 strains including a prototype strain, A/gull/Maryland/704/1977 (H13N6). The HA genes of H13 AIVs were phylogenetically divided into 3 groups (I, II, and III). A/duck/Hokkaido/W345/2012 (H13N2) was genetically classified into Group III. This virus was distinct from a prototype strain, A/gull/Maryland/704/1977 (H13N6), and the virus, A/duck/Hokkaido/WZ68/2012 (H13N2), both belonging to Group I. Antigenic analysis indicated that the viruses of Group I were antigenically closely related to those of Group II, but distinct from those of Group III, including A/duck/Hokkaido/W345/2012 (H13N2). In summary, our study indicates that H13 AIVs have undergone antigenic diversification in nature.
  • Twabela AT, Tshilenge GM, Sakoda Y, Okamatsu M, Bushu E, Kone P, Wiersma L, Zamperin G, Drago A, Zecchin B, Monne I
    Emerging infectious diseases 24 7 1371 - 1374 2018年07月 [査読有り][通常論文]
  • A. Shibata, T. Hiono, H. Fukuhara, R. Sumiyoshi, A. Ohkawara, K. Matsuno, M. Okamatsu, H. Osaka, Y. Sakoda
    Transboundary and Emerging Diseases 65 2 465 - 475 2018年04月01日 [査読有り][通常論文]
     
    The transportation of poultry and related products for international trade contributes to transboundary pathogen spread and disease outbreaks worldwide. To prevent pathogen incursion through poultry products, many countries have regulations about animal health and poultry product quarantine. However, in Japan, animal products have been illegally introduced into the country in baggage and confiscated at the airport. Lately, the number of illegally imported poultry and the incursion risk of transboundary pathogens through poultry products have been increasing. In this study, we isolated avian influenza viruses (AIVs) from raw poultry products illegally imported to Japan by international passengers. Highly (H5N1 and H5N6) and low (H9N2 and H1N2) pathogenic AIVs were isolated from raw chicken and duck products carried by flight passengers. H5 and H9 isolates were phylogenetically closely related to viruses isolated from poultry in China, and haemagglutinin genes of H5N1 and H5N6 isolates belonged to clades 2.3.2.1c and 2.3.4.4, respectively. Experimental infections of H5 and H9 isolates in chickens and ducks demonstrated pathogenicity and tissue tropism to skeletal muscles. To prevent virus incursion by poultry products, it is important to encourage the phased cleaning based on the disease control and eradication and promote the reduction in contamination risk in animal products.
  • S. Sekiguchi, P. Presi, R. Omori, K. Staerk, M. Schuppers, N. Isoda, Y. Yoshikawa, T. Umemura, H. Nakayama, Y. Fujii, Y. Sakoda
    Transboundary and Emerging Diseases 65 1 e135 - e144 2018年02月01日 [査読有り][通常論文]
     
    Bovine viral diarrhoea virus (BVDV) infection in cattle can result in growth retardation, reduced milk production, reproductive disorders and death. Persistently infected animals are the primary source of infection. In Hokkaido, Japan, all cattle entering shared pastures in summer are vaccinated before movement for disease control. Additionally, these cattle may be tested for BVDV and culled if positive. However, the effectiveness of this control strategy aiming to reduce the number of BVDV-infected animals has not been assessed. The aim of this study was to evaluate the effectiveness of various test-and-cull and/or vaccination strategies on BVDV control in dairy farms in two districts of Hokkaido, Nemuro and Hiyama. A stochastic model was developed to compare the different control strategies over a 10-year period. The model was individual-based and simulated disease dynamics both within and between herds. Parameters included in the model were obtained from the literature, the Hokkaido government and the Japanese Ministry of Agriculture, Forestry and Fisheries. Nine different scenarios were compared as follows: no control, test-and-cull strategies based on antigen testing of either calves or only cattle entering common pastures, vaccination of all adult cattle or only cattle entering shared pastures and combinations thereof. The results indicate that current strategies for BVDV control in Hokkaido slightly reduced the number of BVDV-infected animals however, alternative strategies such as testing all calves and culling any positives or vaccinating all susceptible adult animals dramatically reduced those. To our knowledge, this is the first report regarding the comparison of the effectiveness between the current strategies in Hokkaido and the alternative strategies for BVDV control measures.
  • H. Takaki, S. Kure, H. Oshiumi, Y. Sakoda, T. Suzuki, A. Ainai, H. Hasegawa, M. Matsumoto, T. Seya
    Mucosal Immunology 11 1 82 - 96 2018年01月01日 [査読有り][通常論文]
     
    Intranasal inoculation with influenza hemagglutinin subunit with polyinosine-polycytidylic (polyI:C), a synthetic analog for double-stranded RNA, enhances production of vaccine-specific immunoglobulin (Ig) A, which is superior to IgG in prophylactic immunity. The mechanism whereby polyI:C skews to IgA production in the nasal-associated lymph tissue (NALT) was investigated in mouse models. Nasally instilled polyI:C was endocytosed into CD103 + dendritic cells (DCs) and induced T-cell activation, including interferon (IFN)-β 3 production. According to knockout mouse studies, polyI:C activated the Toll-like receptor 3 signal via the adapter TICAM-1 (also called TRIF), that mainly caused T-cell-dependent IgA production. Nasal CD103 + DCs activated transforming growth factor-β signaling and activation-induced cytidine deaminase upon polyI:C stimulation. IgA rather than IgG production was impaired in Batf3 mice, where CD103 + DCs are defective. Genomic recombination occurred in IgA-producing cells in association with polyI:C-stimulated DCs and nasal microenvironment. PolyI:C induced B-cell-activating factor expression and weakly triggered T-cell-independent IgA production. PolyI:C simultaneously activated mitochondrial antiviral signaling and then type I IFN receptor pathways, which only minimally participated in IgA production. Taken together, CD103 + DCs in NALT are indispensable for the adjuvant activity of polyI:C in enhancing vaccine-specific IgA induction and protective immunity against influenza viruses.
  • Mizuho Suzuki, Masatoshi Okamatsu, Yuri Fujimoto, Takahiro Hiono, Keita Matsuno, Hiroshi Kida, Yoshihiro Sakoda
    Japanese Journal of Veterinary Research 66 1 29 - 41 2018年 [査読有り][通常論文]
     
    The H10N8 influenza virus became a threat to public health when cases of fatal infections were identified in China in 2013 and 2014. Thus, genetic and antigenic characterization of H10 influenza viruses and development of an appropriate vaccine are essential to prepare for a future pandemic by H10 influenza viruses. However, current information regarding these properties of H10 influenza viruses circulating in birds is limited. In this study, genetic analysis of H10 influenza viruses revealed that the viruses recently circulating in wild birds in East Asia are genetically close to human H10N8 influenza viruses. Furthermore, the antigenicity of H10 influenza viruses was stable among the viruses circulating in birds. An inactivated vaccine was prepared from A/duck/Mongolia/245/2015 (H10N3), which is genetically and antigenically close to the human H10 influenza viruses. The vaccine induced sufficient neutralizing antibodies against homologous and heterologous viruses in mice. The inactivated vaccine induced protective immunity sufficient to reduce the impact of challenges with A/duck/Hokkaido/W87/2007 (H10N2), which is pathogenic strain in mice. This study demonstrates that the inactivated whole virus particle vaccine prepared from viruses isolated from wild birds would be useful against a future pandemic influenza by H10 influenza viruses.
  • Tomokazu Tamura, Takasuke Fukuhara, Takuro Uchida, Chikako Ono, Hiroyuki Mori, Asuka Sato, Yuzy Fauzyah, Toru Okamoto, Takeshi Kurosu, Yin Xiang Setoh, Michio Imamura, Norbert Tautz, Yoshihiro Sakoda, Alexander A. Khromykh, Kazuaki Chayama, Yoshiharu Matsuura
    Journal of Virology 92 2 2018年01月01日 [査読有り][通常論文]
     
    The family Flaviviridae consists of four genera, Flavivirus, Pestivirus, Pegivirus, and Hepacivirus, and comprises important pathogens of human and animals. Although the construction of recombinant viruses carrying reporter genes encoding fluorescent and bioluminescent proteins has been reported, the stable insertion of foreign genes into viral genomes retaining infectivity remains difficult. Here, we applied the 11-amino-acid subunit derived from NanoLuc luciferase to the engineering of the Flaviviridae viruses and then examined the biological characteristics of the viruses. We successfully generated recombinant viruses carrying the split-luciferase gene, including dengue virus, Japanese encephalitis virus, hepatitis C virus (HCV), and bovine viral diarrhea virus. The stability of the viruses was confirmed by five rounds of serial passages in the respective susceptible cell lines. The propagation of the recombinant luciferase viruses in each cell line was comparable to that of the parental viruses. By using a purified counterpart luciferase protein, this split-luciferase assay can be applicable in various cell lines, even when it is difficult to transduce the counterpart gene. The efficacy of antiviral reagents against the recombinant viruses could be monitored by the reduction of luciferase expression, which was correlated with that of viral RNA, and the recombinant HCV was also useful to examine viral dynamics in vivo. Taken together, our findings indicate that the recombinant Flaviviridae viruses possessing the split NanoLuc luciferase gene generated here provide powerful tools to understand viral life cycle and pathogenesis and a robust platform to develop novel antivirals against Flaviviridae viruses.
  • D. -H. Chu, M. A. Stevenson, L. V. Nguyen, N. Isoda, S. M. Firestone, T. N. Nguyen, L. T. Nguyen, K. Matsuno, M. Okamatsu, H. Kida, Y. Sakoda
    TRANSBOUNDARY AND EMERGING DISEASES 64 6 1991 - 1999 2017年12月 [査読有り][通常論文]
     
    In Vietnam, live bird markets are found in most populated centres, providing the means by which fresh poultry can be purchased by consumers for immediate consumption. Live bird markets are aggregation points for large numbers of poultry, and therefore, it is common for a range of avian influenza viruses to be mixed within live bird markets as a result of different poultry types and species being brought together from different geographical locations. We conducted a cross-sectional study in seven live bird markets in four districts of Thua Thien Hue Province in August and December, 2014. The aims of this study were to (i) document the prevalence of avian influenza in live bird markets (as measured by virus isolation); and (ii) quantify individual bird-, seller- and market-level characteristics that rendered poultry more likely to be positive for avian influenza virus at the time of sale. A questionnaire soliciting details of knowledge, attitude and avian influenza practices was administered to poultry sellers in study markets. At the same time, swabs and faecal samples were collected from individual poultry and submitted for isolation of avian influenza virus. The final data set comprised samples from 1,629 birds from 83 sellers in the seven live bird markets. A total of 113 birds were positive for virus isolation; a prevalence of 6.9 (95% CI 5.8-8.3) avian influenza virus-positive birds per 100 birds submitted for sale. After adjusting for clustering at the market and individual seller levels, none of the explanatory variables solicited in the questionnaire were significantly associated with avian influenza virus isolation positivity. The proportions of variance at the individual market, seller and individual bird levels were 6%, 48% and 46%, respectively. We conclude that the emphasis of avian influenza control efforts in Vietnam should be at the individual seller level as opposed to the market level.
  • Mizuho Suzuki, Masatoshi Okamatsu, Takahiro Hiono, Keita Matsuno, Yoshihiro Sakoda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 79 11 1815 - 1821 2017年11月 [査読有り][通常論文]
     
    H2N2 influenza virus caused a pandemic starting in 1957 but has not been detected in humans since 1968. Thus, most people are immunologically naive to viruses of the H2 subtype. In contrast, H2 influenza viruses are continually isolated from wild birds, and H2N3 viruses were isolated from pigs in 2006. H2 influenza viruses could cause a pandemic if re-introduced into humans. In the present study, a vaccine against H2 influenza was prepared as an effective control measure against a future human pandemic. A/duck/Hokkaido/162/2013 (H2N1), which showed broad antigenic cross-reactivity, was selected from the candidate H2 influenza viruses recently isolated from wild birds in Asian countries. Sufficient neutralizing antibodies against homologous and heterologous viruses were induced in mice after two subcutaneous injections of the inactivated whole virus particle vaccine. The inactivated vaccine induced protective immunity sufficient to reduce the impact of challenges with A/swine/Missouri/2124514/2006 (H2N3). This study demonstrates that the inactivated whole virus particle vaccine prepared from an influenza virus library would be useful against a future H2 influenza pandemic.
  • Tumenjargal Sharav, Satoru Konnai, Nyamsuren Ochirkhuu, Erdene T. S. Ochir, Hirohisa Mekata, Yoshihiro Sakoda, Takashi Umemura, Shiro Murata, Tungalag Chultemdorj, Kazuhiko Ohashi
    JOURNAL OF VETERINARY MEDICAL SCIENCE 79 11 1884 - 1888 2017年11月 [査読有り][通常論文]
     
    The genetic characterization and actual prevalence of EIAV in Mongolian horse in the disease endemic region is currently unknown. Here, 11 of 776 horse serum samples from four Mongolian provinces tested positive on agar gel immunodiffusion test. Genomic DNA extracted from all seropositive samples was subjected to nested PCR assay. Among these, three samples tested positive with nested PCR assay and were identified by sequencing analysis based on long termination repeat and tat gene of the virus. Two of the three sequences were identical, with 94.0% identity with the third. These two independent Mongolian EIAV sequences were retained functional motifs, with no dramatic changes but some variability in the U5 region; they were clustered with genotypes from European countries but not with those from China, U.S.A., or Japan.
  • Lam Thanh Nguyen, Tatsuya Nishi, Shintaro Shichinohe, Duc-Huy Chu, Takahiro Hiono, Keita Matsuno, Masatoshi Okamatsu, Hiroshi Kida, Yoshihiro Sakoda
    VIROLOGY 510 252 - 261 2017年10月 [査読有り][通常論文]
     
    Vaccination-primed immunity in poultry has been suggested for selection of antigenically drifted highly pathogenic avian influenza viruses (HPAIVs). In this study, we performed two consecutive passage studies of an H5N1 HPAIV in vaccinated chickens, namely, study-I and study-II, to select antigenic variants under immune pressure from the vaccination. In study-I, nine consecutive passages of a wild-type H5N1 HPAIV were carried out in chickens vaccinated with the homologous challenge strain. Antigenically drifted variants with mutations at position 179 in the hemagglutinin (HA) were selected after three passages. Similarly, in study-II, a vaccination-mediated antigenic variant isolated in study-I was used as the vaccine and challenge strain to confirm further antigenic drift after updating the vaccine; after the third passage, additional antigenic variants with a mutation at position 256 in the HA were selected. Thus, our study demonstrated the contribution of vaccination in the selection of antigenic variants of H5 HPAIVs in chickens.
  • Engineering of Small Reporter-Tagged Flaviviridae Viruses Applicable to Antiviral Screening and in vivo Dynamics
    Tomokazu Tamura, Takasuke Fukuhara, Akatuski Saito, Takuro Uchida, Chikako Ono, Hiroyuki Mori, Toru Okamoto, Takeshi Kurosu, Norbert Tautz, Yoshihiro Sakoda, Tatuso Shioda, Kazuaki Chayama, Yoshiharu Matsuura
    2017年09月 [査読無し][通常論文]
  • Takahiro Hiono, Masatoshi Okamatsu, Keita Matsuno, Atsushi Haga, Ritsuko Iwata, Lam Thanh Nguyen, Mizuho Suzuki, Yuto Kikutani, Hiroshi Kida, Manabu Onuma, Yoshihiro Sakoda
    MICROBIOLOGY AND IMMUNOLOGY 61 9 387 - 397 2017年09月 [査読有り][通常論文]
     
    On 15 November 2016, a black swan that had died in a zoo in Akita prefecture, northern Japan, was strongly suspected to have highly pathogenic avian influenza (HPAI); an HPAI virus (HPAIV) belonging to the H5N6 subtype was isolated from specimens taken from the bird. After the initial report, 230 cases of HPAI caused by H5N6 viruses from wild birds, captive birds, and domestic poultry farms were reported throughout the country during the winter season. In the present study, 66 H5N6 HPAIVs isolated from northern Japan were further characterized. Phylogenetic analysis of the hemagglutinin gene showed that the H5N6 viruses isolated in northern Japan clustered into Group C of Clade 2.3.4.4 together with other isolates collected in Japan, Korea and Taiwan during the winter season of 2016-2017. The antigenicity of the Japanese H5N6 isolate differed slightly from that of HPAIVs isolated previously in Japan and China. The virus exhibited high pathogenicity and a high replication capacity in chickens, whereas virus growth was slightly lower in ducks compared with that of an H5N8 HPAIV isolate collected in Japan in 2014. Comprehensive analyses of Japanese isolates, including those from central, western, and southern Japan, as well as rapid publication of this information are essential for facilitating greater control of HPAIVs.
  • Marina Gulyaeva, Kirill Sharshov, Mizuho Suzuki, Ivan Sobolev, Yoshihiro Sakoda, Alexander Alekseev, Mariya Sivay, Lidia Shestopalova, Michael Shchelkanov, Alexander Shestopalov
    JOURNAL OF VETERINARY MEDICAL SCIENCE 79 8 1461 - 1465 2017年08月 [査読有り][通常論文]
     
    Thirty-two muskrats (Ondatra zibethicus) were captured for surveillance of avian influenza virus in wild waterfowl and mammals near Lake Chany, Western Siberia, Russia. A/muskrat/Russia/63/2014 (H2N2) was isolated from an apparently healthy muskrat using chicken embryos. Based on phylogenetic analysis, the hemagglutinin and neuraminidase genes of this isolate were classified into the Eurasian avian-like influenza virus clade and closely related to low pathogenic avian influenza viruses (LPAIVs) isolated from wild water birds in Italy and Sweden, respectively. Other internal genes were also closely related to LPAIVs isolated from Eurasian wild water birds. Results suggest that interspecies transmission of LPAIVs from wild water birds to semiaquatic mammals occurs, facilitating the spread and evolution of LPAIVs in wetland areas of Western Siberia.
  • Lam Thanh Nguyen, Kazunari Nakaishi, Keiko Motojima, Ayako Ohkawara, Erina Minato, Junki Maruyama, Takahiro Hiono, Keita Matsuno, Masatoshi Okamatsu, Takashi Kimura, Ayato Takada, Hiroshi Kida, Yoshihiro Sakoda
    PLOS ONE 12 8 e0182228  2017年08月 [査読有り][通常論文]
     
    Highly pathogenic avian influenza viruses (HPAIVs) of H5 subtype have persistently caused outbreaks in domestic poultry and wild birds worldwide and sporadically infected humans. Rapid and accurate diagnosis is one of the key strategies for the control of H5 HPAIVs. However, the sensitivity of the diagnosis of H5 HPAIVs has gradually reduced due to extensive antigenic variation during their evolution. Particularly, the previously developed immunochromatographic diagnosis kit for H5 viruses, Linjudge Flu A/H5, exhibits reduced detection of H5 HPAIVs isolated in recent years. In the present study, we established a new advanced H5 rapid immunochromatographic detection kit (New Linjudge Flu A/H5) by a combination of two anti-H5 hemagglutinin monoclonal antibodies, A64/1 previously applied in the Linjudge Flu A/H5 and A32/2, a novel monoclonal antibody generated from a clade 2.3.4.4 H5 HPAIV. The new kit broadly detected all classical and recent H5 influenza viruses and showed a higher specificity and sensitivity than the original Linjudge Flu A/H5 with recently circulating H5 HPAIVs. Furthermore, the applicability of the New Linjudge Flu A/H5 was demonstrated by detecting antigens from the swabs and tissue homogenates of naturally infected birds and experimentally infected chickens with H5N6 HPAIVs belonging to the genetic clade 2.3.4.4. Our study, therefore, can provide an effective point-of-care rapid antigen detection kit for the surveillance of H5 avian influenza viruses and as a prompt countermeasure against the current widespread of the clade 2.3.4.4 H5 HPAIVs in domestic and wild birds.
  • Norikazu Isoda, Akihiro Asano, Michiru Ichijo, Shiho Wakamori, Hiroshi Ohno, Kazuhiko Sato, Hirokazu Okamoto, Shigeru Nakao, Hajime Kato, Kazuma Saito, Naoki Ito, Akira Usui, Hiroaki Takayama, Yoshihiro Sakoda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 79 7 1172 - 1181 2017年07月 [査読有り][通常論文]
     
    A scenario tree model was developed to propose efficient bovine viral diarrhea (BVD) control measures. The model used field data in eastern Hokkaido where the risk of BVDV infection in cattle has been reduced by an eradication program including mass vaccination, individual tests prior to communal pasture grazing, herd screening tests using bulk milk, and outbreak investigations of newly infected herds. These four activities were then used as hypothesized control measures in the simulation. In each simulation, the numbers of cattle infected persistently and transiently with BVDV detected by clinical manifestations and diagnosis tests and of missed by all of the diagnosis tests were calculated, and the numbers were used as indicators to be compared for the efficacy of the control measures. The model outputs indicated that the adoption of mass vaccination decreased the number of missed BVD cattle, although it did not increase the number of detected BVD cattle. Under implementation of mass vaccination, the efficacy of individual tests on selected 20% of the young and adult cattle was equal to that of the herd screening test performed in all the herds. When the virus prevalence or the number of sensitive animals becomes low, the efficacy of herd screening test was superior to one of individual tests. Considering the model outputs together, the scenario tree model developed in the present study was useful to compare the efficacy of the control measures for BVD.
  • Takasuke Fukuhara, Tomokazu Tamura, Chikako Ono, Mai Shiokawa, Hiroyuki Mori, Kentaro Uemura, Satomi Yamamoto, Takeshi Kurihara, Toru Okamoto, Ryosuke Suzuki, Kentaro Yoshii, Takeshi Kurosu, Manabu Igarashi, Hiroshi Aoki, Yoshihiro Sakoda, Yoshiharu Matsuura
    PLOS PATHOGENS 13 6 e1006475  2017年06月 [査読有り][通常論文]
     
    Amphipathic alpha-helices of exchangeable apolipoproteins have shown to play crucial roles in the formation of infectious hepatitis C virus (HCV) particles through the interaction with viral particles. Among the Flaviviridae members, pestivirus and flavivirus possess a viral structural protein E-rns or a non-structural protein 1 (NS1) as secretory glycoproteins, respectively, while Hepacivirus including HCV has no secretory glycoprotein. In case of pestivirus replication, the C-terminal long amphipathic alpha-helices of E-rns are important for anchoring to viral membrane. Here we show that host-derived apolipoproteins play functional roles similar to those of virally encoded E-rns and NS1 in the formation of infectious particles. We examined whether E-rns and NS1 could compensate for the role of apolipoproteins in particle formation of HCV in apolipoprotein B (ApoB) and ApoE double-knockout Huh7 (BE-KO), and nonhepatic 293T cells. We found that exogenous expression of either E-rns or NS1 rescued infectious particle formation of HCV in the BE-KO and 293T cells. In addition, expression of apolipoproteins or NS1 partially rescued the production of infectious pestivirus particles in cells upon electroporation with an E-rns-deleted non-infectious RNA. As with exchangeable apolipoproteins, the C-terminal amphipathic alpha-helices of E-rns play the functional roles in the formation of infectious HCV or pestivirus particles. These results strongly suggest that the host-and virus-derived secretory glycoproteins have overlapping roles in the viral life cycle of Flaviviridae, especially in the maturation of infectious particles, while E-rns and NS1 also participate in replication complex formation and viral entry, respectively. Considering the abundant hepatic expression and liver-specific propagation of these apolipoproteins, HCV might have evolved to utilize them in the formation of infectious particles through deletion of a secretory viral glycoprotein gene.
  • Bazarragchaa Enkhbold, Munkhduuren Shatar, Shiho Wakamori, Tomokazu Tamura, Takahiro Hiono, Keita Matsuno, Masatoshi Okamatsu, Takashi Umemura, Batchuluun Damdinjav, Yoshihiro Sakoda
    VIRUS GENES 53 3 418 - 425 2017年06月 [査読有り][通常論文]
     
    Classical swine fever (CSF), a highly contagious viral disease affecting domestic and wild pigs in many developing countries, is now considered endemic in Mongolia, with 14 recent outbreaks in 2007, 2008, 2011, 2012, 2014, and 2015. For the first time, CSF viruses isolated from these 14 outbreaks were analyzed to assess their molecular epidemiology and pathogenicity in pigs. Based on the nucleotide sequences of their 5'-untranslated region, isolates were phylogenetically classified as either sub-genotypes 2.1b or 2.2, and the 2014 and 2015 isolates, which were classified as 2.1b, were closely related to isolates from China and Korea. In addition, at least three different viruses classified as 2.1b circulated in Mongolia. Experimental infection of the representative isolate in 2014 demonstrated moderate pathogenicity in 4-week-old pigs, with relatively mild clinical signs. Understanding the diversity of circulating CSF viruses gleans insight into disease dynamics and evolution, and may inform the design of effective CSF control strategies in Mongolia.
  • Ayako Ohkawara, Masatoshi Okamatsu, Makoto Ozawa, Duc-Huy Chu, Lam Thanh Nguyen, Takahiro Hiono, Keita Matsuno, Hiroshi Kida, Yoshihiro Sakoda
    MICROBIOLOGY AND IMMUNOLOGY 61 5 149 - 158 2017年05月 [査読有り][通常論文]
     
    H5 highly pathogenic avian influenza viruses (HPAIV) have spread in both poultry and wild birds since late 2003. Continued circulation of HPAIV in poultry in several regions of the world has led to antigenic drift. In the present study, we analyzed the antigenic properties of H5 HPAIV isolated in Asia using four neutralizing mAbs recognizing hemagglutinin, which were established using A/chicken/Kumamoto/1-7/2014 (H5N8), belonging to clade 2.3.4.4 and also using polyclonal antibodies. Viruses of clades 1.1, 2.3.2.1, 2.3.4, and 2.3.4.4 had different reactivity patterns to the panel of mAbs, thereby indicating that the antigenicity of the viruses of clade 2.3.4.4 were similar but differed from the other clades. In particular, the antigenicity of the viruses of clade 2.3.4.4 differed from those of the viruses of clades 2.3.4 and 2.3.2.1, which suggests that the recent H5 HPAIV have further evolved antigenically divergent. In addition, reactivity of antiserum suggests that the antigenicity of viruses of clade 2.3.4.4 differed slightly among groups A, B, and C. Vaccines are still used in poultry in endemic countries, so the antigenicity of H5 HPAIV should be monitored continually to facilitate control of avian influenza. The panel of mAbs established in the present study will be useful for detecting antigenic drift in the H5 viruses that emerge from the current strains.
  • Akihiro Nakatsukasa, Koji Kuruma, Masatoshi Okamatsu, Takahiro Hiono, Mizuho Suzuki, Keita Matsuno, Hiroshi Kida, Takayoshi Oyamada, Yoshihiro Sakoda
    VACCINE 35 21 2855 - 2861 2017年05月 [査読有り][通常論文]
     
    Transdermal vaccination using a microneedle (MN) confers enhanced immunity compared with subcutaneous (SC) vaccination. Here we developed a novel dissolving MN patch for the influenza vaccine. The potencies of split virion and whole virus particle (WVP) vaccines prepared from A/Puerto Rico/8/1934 (H1N1) and A/duck/Hokkaido/Vac-3/2007 (H5N1), respectively, were evaluated. MN vaccination induced higher neutralizing antibody responses than SC vaccination in mice. Moreover, MN vaccination with a lower dose of antigens conferred protective immunity against lethal challenges of influenza viruses than SC vaccination in mice. These results suggest that the WVP vaccines administered using MN are an effective combination for influenza vaccine to be further validated in humans. (C) 2017 Elsevier Ltd. All rights reserved.
  • Masatoshi Okamatsu, Makoto Ozawa, Kosuke Soda, Hiroki Takakuwa, Atsushi Haga, Takahiro Hiono, Aya Matsuu, Yuko Uchida, Ritsuko Iwata, Keita Matsuno, Masakazu Kuwahara, Toshiyo Yabuta, Tatsufumi Usui, Hiroshi Ito, Manabu Onuma, Yoshihiro Sakoda, Takehiko Saito, Koichi Otsuki, Toshihiro Ito, Hiroshi Kida
    EMERGING INFECTIOUS DISEASES 23 4 691 - 695 2017年04月 [査読有り][通常論文]
     
    Highly pathogenic avian influenza viruses (HPAIVs) A(H5N6) were concurrently introduced into several distant regions of Japan in November 2016. These viruses were classified into the genetic clade 2.3.4.4c and were genetically closely related to H5N6 HPAIVs recently isolated in South Korea and China. In addition, these HPAIVs showed further antigenic drift.
  • Masanori Kobayashi, Makoto Kodama, Takeshi Noshi, Ryu Yoshida, Takushi Kanazu, Naoki Nomura, Kosuke Soda, Norikazu Isoda, Masatoshi Okamatsu, Yoshihiro Sakoda, Yoshinori Yamano, Akihiko Sato, Hiroshi Kida
    ANTIVIRAL RESEARCH 139 41 - 48 2017年03月 [査読有り][通常論文]
     
    High morbidity and mortality associated with human cases of highly pathogenic avian influenza (HPAI) viruses, including H5N1 influenza virus, have been reported. The purpose of the present study was to evaluate the antiviral effects of peramivir against HPAI viruses. In neuraminidase (NA) inhibition and virus replication inhibition assays, peramivir showed strong inhibitory activity against H5N1, H7N1 and H7N7 HPAI viruses with sub-nanomolar activity in enzyme assays. In H5N1 viruses containing the NA H275Y mutation, the antiviral activity of peramivir against the variant was lower than that against the wild-type. Evaluation of the in vivo antiviral activity showed that a single intravenous treatment of peramivir (10 mg/kg) prevented lethality in mice infected with wild-type H5N1 virus and also following infection with H5N1 virus with the H275Y mutation after a 5 day administration of peramivir (30 mg/kg). Furthermore, mice injected with peramivir showed low viral titers and low levels of proinflammatory cytokines in the lungs. These results suggest that peramivir has therapeutic activity against HPAI viruses even if the virus harbors the NA H275Y mutation. (C) 2016 Elsevier B.V. All rights reserved.
  • Misako Nakayama, Yasushi Itoh, Shintaro Shichinohe, Rumi Nakabayashi, Hirohito Ishigaki, Yoshihiro Sakoda, Quynh Mai Le, Yoshihiro Kawaoka, Hiroshi Kida, Kazumasa Ogasawara
    VACCINE 35 7 1008 - 1017 2017年02月 [査読有り][通常論文]
     
    The efficacy and detrimental effect of mucosal vaccination with an inactivated influenza vaccine were examined in a macaque model by intranasal administration with small amounts of inactivated whole virus particles and challenge by a human-derived H5N1 highly pathogenic avian influenza virus infection. Repeated nasal inoculation with the whole particle vaccine of an inactivated virus, A/duck/Hokkaido/Vac-3/2007 (H5N1) (Vac-3), induced antigen-specific IgA and IgG antibody production in nasal swabs and plasma. Vac-3-specific IgE production was also found in the nasal swabs. Nasal vaccination with Vac-3 induced broader cross-clade neutralization activity than did subcutaneous vaccination. After challenge infection, repeated nasal vaccination almost completely prevented the propagation of virus in the upper and lower airways and protected cynomolgus macaques from viral pneumonia by induction of IgA-producing B cells in the lungs. On the other hand, eosinophil clusters were observed in the lungs of vaccinated macaques. Although Vac-3-specific IgE antibody and IL-13 levels were decreased after infection compared to those before infection and no anaphylaxis in vaccinated macaques was detected after challenge infection, our results suggest that we have to pay attention to potential allergic responses at repeated nasal vaccination, especially in people who have an airway allergy. (C) 2017 Elsevier Ltd. All rights reserved.
  • Takasuke Fukuhara, Tomokazu Tamura, Chikako Ono, Mai Shiokawa, Hiroyuki Mori, Kentaro Uemura, Satomi Yamamoto, Takeshi Kurihara, Toru Okamoto, Ryosuke Suzuki, Kentaro Yoshii, Takeshi Kurosu, Manabu Igarashi, Hiroshi Aoki, Yoshihiro Sakoda, Yoshiharu Matsuura
    PLoS Pathogens 13 6 2017年 [査読有り][通常論文]
     
    Amphipathic α-helices of exchangeable apolipoproteins have shown to play crucial roles in the formation of infectious hepatitis C virus (HCV) particles through the interaction with viral particles. Among the Flaviviridae members, pestivirus and flavivirus possess a viral structural protein Ernsor a non-structural protein 1 (NS1) as secretory glycoproteins, respectively, while Hepacivirus including HCV has no secretory glycoprotein. In case of pestivirus replication, the C-terminal long amphipathic α-helices of Ernsare important for anchoring to viral membrane. Here we show that host-derived apolipoproteins play functional roles similar to those of virally encoded Ernsand NS1 in the formation of infectious particles. We examined whether Ernsand NS1 could compensate for the role of apolipoproteins in particle formation of HCV in apolipoprotein B (ApoB) and ApoE double-knockout Huh7 (BE-KO), and non-hepatic 293T cells. We found that exogenous expression of either Ernsor NS1 rescued infectious particle formation of HCV in the BE-KO and 293T cells. In addition, expression of apolipoproteins or NS1 partially rescued the production of infectious pestivirus particles in cells upon electroporation with an Erns-deleted non-infectious RNA. As with exchangeable apolipoproteins, the C-terminal amphipathic α-helices of Ernsplay the functional roles in the formation of infectious HCV or pestivirus particles. These results strongly suggest that the host- and virus-derived secretory glycoproteins have overlapping roles in the viral life cycle of Flaviviridae, especially in the maturation of infectious particles, while Ernsand NS1 also participate in replication complex formation and viral entry, respectively. Considering the abundant hepatic expression and liver-specific propagation of these apolipoproteins, HCV might have evolved to utilize them in the formation of infectious particles through deletion of a secretory viral glycoprotein gene.
  • Misako Nakayama, Hiroichi Ozaki, Yasushi Itoh, Kosuke Soda, Hirohito Ishigaki, Masatoshi Okamatsu, Yoshihiro Sakoda, Chun-Ho Park, Hideaki Tsuchiya, Hiroshi Kida, Kazumasa Ogasawara
    PATHOLOGY INTERNATIONAL 66 12 678 - 686 2016年12月 [査読有り][通常論文]
     
    H9N2 avian influenza virus causes sporadic human infection. Since humans do not possess acquired immunity specific to this virus, we examined the pathogenicity of an H9N2 virus isolated from a human and then analyzed protective effects of a vaccine in cynomolgus macaques. After intranasal challenge with A/Hong Kong/1073/1999 (H9N2) (HK1073) isolated from a human patient, viruses were isolated from nasal and tracheal swabs in unvaccinated macaques with mild fever and body weight loss. A formalin-inactivated H9N2 whole particle vaccine derived from our virus library was subcutaneously inoculated to macaques. Vaccination induced viral antigen-specific IgG and neutralization activity in sera. After intranasal challenge with H9N2, the virus was detected only the day after inoculation in the vaccinated macaques. Without vaccination, many bronchus-associated lymphoid tissues (BALTs) were formed in the lungs after infection, whereas the numbers of BALTs were smaller and the cytokine responses were weaker in the vaccinated macaques than those in the unvaccinated macaques. These findings indicate that the H9N2 avian influenza virus HK1073 is pathogenic in primates but seems to cause milder symptoms than does H7N9 influenza virus as found in our previous studies and that a formalin-inactivated H9N2 whole particle vaccine induces protective immunity against H9N2 virus.
  • Fumihiko Yasui, Yasushi Itoh, Ai Ikejiri, Masahiro Kitabatake, Nobuo Sakaguchi, Keisuke Munekata, Shintaro Shichinohe, Yukiko Hayashi, Hirohito Ishigaki, Misako Nakayama, Yoshihiro Sakoda, Hiroshi Kida, Kazumasa Ogasawara, Michinori Kohara
    SCIENTIFIC REPORTS 6 37915  2016年11月 [査読有り][通常論文]
     
    H5N1 highly pathogenic avian influenza (H5N1 HPAI) virus causes elevated mortality compared with seasonal influenza viruses like H1N1 pandemic influenza (H1N1 pdm) virus. We identified a mechanism associated with the severe symptoms seen with H5N1 HPAI virus infection. H5N1 HPAI virus infection induced a decrease of dendritic cell number in the splenic extrafollicular T-cell zone and impaired formation of the outer layers of B-cell follicles, resulting in insufficient levels of antibody production after infection. However, in animals vaccinated with a live recombinant vaccinia virus expressing the H5 hemagglutinin, infection with H5N1 HPAI virus induced parafollicular dendritic cell accumulation and efficient antibody production. These results indicate that a recombinant vaccinia encoding H5 hemagglutinin gene does not impair dendritic cell recruitment and can be a useful vaccine candidate.
  • Samantha J. Lycett, Rogier Bodewes, Anne Pohlmann, Jill Banks, Krisztian Banyai, Maciej F. Boni, Ruth Bouwstra, Andrew C. Breed, Ian H. Brown, Hualan Chen, Adam Dan, Thomas J. DeLiberto, Nguyen Diep, Marius Gilbert, Sarah Hill, Hon S. Ip, Chang Wen Ke, Hiroshi Kida, Mary Lea Killian, Marion P. Koopmans, Jung-Hoon Kwon, Dong-Hun Lee, Youn Jeong Lee, Lu Lu, Isabella Monne, John Pasick, Oliver G. Pybus, Andrew Rambaut, Timothy P. Robinson, Yoshihiro Sakoda, Siamak Zohari, Chang-Seon Song, David E. Swayne, Mia Kim Torchetti, Hsiang-Jung Tsai, Ron A. M. Fouchier, Martin Beer, Mark Woolhouse, Thijs Kuiken
    SCIENCE 354 6309 213 - 217 2016年10月 [査読有り][通常論文]
     
    Avian influenza viruses affect both poultry production and public health. A subtype H5N8 (clade 2.3.4.4) virus, following an outbreak in poultry in South Korea in January 2014, rapidly spread worldwide in 2014-2015. Our analysis of H5N8 viral sequences, epidemiological investigations, waterfowl migration, and poultry trade showed that long-distance migratory birds can play a major role in the global spread of avian influenza viruses. Further, we found that the hemagglutinin of clade 2.3.4.4 virus was remarkably promiscuous, creating reassortants with multiple neuraminidase subtypes. Improving our understanding of the circumpolar circulation of avian influenza viruses in migratory waterfowl will help to provide early warning of threats from avian influenza to poultry, and potentially human, health.
  • フラビウイルス科ウイルスの粒子産生における分泌性糖タンパク質の役割
    Tomokazu Tamura, Takasuke Fukuhara, Mai Shiokawa, Chikako Ono, Satomi Yamamoto, Hiroyuki Mori, Takeshi Kurihara, Toru Okamoto, Hiroshi Aoki, Yoshihiro Sakoda, Yoshiharu Matsuura
    2016年10月 [査読無し][通常論文]
  • The roles of secretory glycoproteins in viral particle formation in family Flaviviridae
    Tomokazu Tamura, Takasuke Fukuhara, Mai Shiokawa, Chikako Ono, Satomi Yamamoto, Hiroyuki Mori, Takeshi Kurihara, Toru Okamoto, Hiroshi Aoki, Yoshihiro Sakoda, Yoshiharu Matsuura
    2016年10月 [査読有り][通常論文]
  • Viral secretory glycoproteins of Flaviviridae virus have similar roles with apolipoproteins on the formation of infectious HCV particles
    Takasuke Fukuhara, Tomokazu Tamura, Mai Shiokawa, Chikako Ono, Satomi Yamamoto, Hiroyuki Mori, Takeshi Kurihara, Kentaro Uemura, Toru Okamoto, Hiroshi Aoki, Yoshihiro Sakoda, Yoshiharu Matsuura
    2016年10月 [査読有り][通常論文]
  • Taisuke Horimoto, Takahiro Hiono, Hirohisa Mekata, Tomoha Odagiri, Zhihao Lei, Tomoya Kobayashi, Junzo Norimine, Yasuo Inoshima, Hirokazu Hikono, Kenji Murakami, Reiichiro Sato, Hironobu Murakami, Masahiro Sakaguchi, Kazunori Ishii, Takaaki Ando, Kounosuke Otomaru, Makoto Ozawa, Yoshihiro Sakoda, Shin Murakami
    PLOS ONE 11 9 e0163828  2016年09月 [査読有り][通常論文]
     
    Cattle are major reservoirs of the provisionally named influenza D virus, which is potentially involved in the bovine respiratory disease complex. Here, we conducted a serological survey for the influenza D virus in Japan, using archived bovine serum samples collected during 2010-2016 from several herds of apparently healthy cattle in various regions of the country. We found sero-positive cattle across all years and in all the prefectural regions tested, with a total positivity rate of 30.5%, although the positivity rates varied among regions (13.5-50.0%). There was no significant difference in positivity rates for Holstein and Japanese Black cattle. Positivity rates tended to increase with cattle age. The herds were clearly divided into two groups: those with a high positive rate and those with a low (or no) positive rate, indicating that horizontal transmission of the virus occurs readily within a herd. These data demonstrate that bovine influenza D viruses have been in circulation for at least 5 years countrywide, emphasizing its ubiquitous distribution in the cattle population of Japan.
  • Masatoshi Okamatsu, Takahiro Hiono, Hiroshi Kida, Yoshihiro Sakoda
    VETERINARY JOURNAL 215 82 - 86 2016年09月 [査読有り][通常論文]
     
    The diagnosis of influenza A virus infections in poultry or wild birds is difficult due to variations in the pathogenicity of the viruses in different avian hosts and also the antigenic and genetic diversity of the virus, particularly the recent H5 highly pathogenic avian influenza viruses. A classical standard laboratory technique is virus isolation prior to subtyping and pathotyping. This diagnostic technique is crucial for further virological analyses, particularly during an initial outbreak; however, delays in diagnosis have thwarted effective disease control in recent years. Recent developments in molecular biological techniques provide an accelerated diagnosis. Such technologies, which include real-time reverse transcriptase PCR, isothermal nucleic acid amplification, next-generation sequencing and immunochromatography, contribute to simpler and more rapid diagnosis. The advantages of each of these diagnostic techniques should be considered for effective control of avian influenza. (C) 2016 Elsevier Ltd. All rights reserved.
  • Duc-Huy Chu, Masatoshi Okamatsu, Keita Matsuno, Takahiro Hiono, Kohei Ogasawara, Lam Thanh Nguyen, Long Van Nguyen, Tien Ngoc Nguyen, Thuy Thu Nguyen, Dong Van Pham, Dang Hoang Nguyen, Tho Dang Nguyen, Thanh Long To, Hung Van Nguyen, Hiroshi Kida, Yoshihiro Sakoda
    VETERINARY MICROBIOLOGY 192 194 - 203 2016年08月 [査読有り][通常論文]
     
    A total of 3,045 environmental samples and oropharyngeal and cloacal swabs from apparently healthy poultry have been collected at three live bird markets (LBMs) at which practices were applied to reduce avian influenza (AI) virus transmission (intervention LBMs) and six conventional LBMs (non-intervention LBMs) in Thua Thien Hue province in 2014 to evaluate the efficacy of the intervention LBMs. The 178 AI viruses, including H3 (19 viruses), H4 (2), H5 (8), H6 (30), H9 (114), and H11 (5), were isolated from domestic ducks, muscovy ducks, chickens, and the environment. The prevalence of AI viruses in intervention LBMs (6.1%; 95% CI: 5.0-7.5) was similar to that in non-intervention LBMs (5.6%; 95% CI: 4.5-6.8; x(2) = 0.532; df = 1; P = 0.53) in the study area. Eight H5N6 highly pathogenic avian influenza (HPAI) viruses were isolated from apparently healthy ducks, muscovy ducks, and an environmental sample in an intervention LBM. The hemagglutinin genes of the H5N6 HPAI viruses belonged to the genetic Glade 23.4.4, and the antigenicity of the H5N6 HPAI viruses differed from the H5N1 HPAI viruses previously circulating in Vietnam. Phylogenetic and antigenic analyses of the H6 and H9 viruses isolated in both types of LBMs revealed that they were closely related to the viruses isolated from domestic birds in China, Group II of H6 viruses and Y280 lineage of H9 viruses. These results indicate that the interventions currently applied in LBMs are insufficient to control AI. A risk analysis should be conducted to identify the key factors contributing to Al virus prevalence in intervention LBMs. (C) 2016 Elsevier B.V. All rights reserved.
  • Hiromichi Mitake, Yuji Fujii, Makoto Nagai, Naoto Ito, Kota Okadera, Kazuma Okada, Kento Nakagawa, Mai Kishimoto, Tetsuya Mizutani, Katsunori Okazaki, Yoshihiro Sakoda, Ayato Takada, Makoto Sugiyama
    JOURNAL OF GENERAL VIROLOGY 97 8 1818 - 1822 2016年08月 [査読有り][通常論文]
     
    Ljungan virus (LV) has been isolated/detected from rodents in a limited area including European countries and the USA. In this study, we isolated an LV strain from faecal samples of wild birds that had been collected in Japan, and determined the nearly complete sequence of the genome. Sequence analyses showed that the isolate possesses an LV-like genomic organization: 5UTR-VP0-VP3-VP1-2A1-2A2-2B-2C-3A-3B-3C-3D-3UTR. Phylogenetic and similarity analyses based on the VP1 region indicated that the strain constitutes a novel genotype within LV. In addition, we identified species origin of the faeces as gull species by using the DNA barcoding technique. These data suggested that the novel LV strain infected a gull species, in which the virus had not been identified. Taken together, this study has provided the first evidence of the presence of a novel LV in Japan, highlighting the possibility of LV infection in birds.
  • Masatoshi Okamatsu, Yurie Motohashi, Takahiro Hiono, Tomokazu Tamura, Kazuki Nagaya, Keita Matsuno, Yoshihiro Sakoda, Hiroshi Kida
    ARCHIVES OF VIROLOGY 161 8 2235 - 2242 2016年08月 [査読有り][通常論文]
     
    Influenza viruses isolated from wild ducks do not replicate in chickens. This fact is not explained solely by the receptor specificity of the hemagglutinin (HA) from such viruses for target host cells. To investigate this restriction in host range, the fusion activities of HA molecules from duck and chicken influenza viruses were examined. Influenza viruses A/duck/Mongolia/54/2001 (H5N2) (Dk/MNG) and A/chicken/Ibaraki/1/2005 (H5N2) (Ck/IBR), which replicate only in their primary hosts, were used. The optimal pH for membrane fusion of Ck/IBR was 5.9, higher than that of Dk/MNG at 4.9. To assess the relationship between the optimal pH for fusion and the host range of avian influenza viruses, the optimal pH for fusion of 55 influenza virus strains isolated from ducks and chickens was examined. No correlation was found between the host range and optimal pH for membrane fusion by the viruses, and this finding applied also to the H5N1 highly pathogenic avian influenza viruses. The optimal pH for membrane fusion for avian influenza viruses was shown to not necessarily be correlated with their host range or pathogenicity in ducks and chickens.
  • Shintaro Shichinohe, Yasushi Itoh, Misako Nakayama, Hiroichi Ozaki, Kosuke Soda, Hirohito Ishigaki, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Kazumasa Ogasawara
    VIROLOGY 493 31 - 38 2016年06月 [査読有り][通常論文]
     
    The outbreak of H7N9 low pathogenic avian influenza viruses in China has attracted attention to H7 influenza virus infection in humans. Since we have shown that the pathogenicity of H1N1 and H5N1 influenza viruses in macaques was almost the same as that in humans, we compared the pathogenicities of H7 avian influenza viruses in cynomolgus macaques via intranasal and conjunctival inoculation, which mimics natural infection in humans. H7N9 virus, as well as H7N7 highly pathogenic avian influenza virus, showed more efficient replication and higher pathogenicity in macaques than did H7N1 and H7N3 highly pathogenic avian influenza viruses. These results are different from pathogenicity in chickens as reported previously. Therefore, our results obtained in macaques help to estimate the pathogenicity of H7 avian influenza viruses in humans. (C) 2016 Elsevier Inc. All rights reserved.
  • Hiroshi Yamada, Satoshi Nagase, Kazuo Takahashi, Yoshihiro Sakoda, Hiroshi Kida, Shigefumi Okamoto
    ANTIVIRAL RESEARCH 129 81 - 92 2016年05月 [査読有り][通常論文]
     
    The most effective drugs available to treat influenza are neuraminidase (NA) inhibitors, which provide important additional measures for the control of influenza virus infections. However, since the emergence of NA inhibitor-resistant viruses may compromise the clinical utility of this class of anti-influenza agents, it is very important to develop new anti-influenza agents which target a different region in NA responsible for its sensitivity from that for NA inhibitors and could be used to treat NA inhibitors resistant isolates. The oligodeoxynucleotide D35, multimerized and aggregated, suppressed replication of influenza A viruses except A/WSN/33 (WSN). The suppressive viral replication by D35 depended on G-terad and multimer formation. The range of the suppressive viral replication at the late stage, including virus assembly and release from infected cells, was much larger than that at the initial stage, viral attachment and entry. D35 suppressed NA activity of influenza A viruses. Furthermore, replacing the NA gene of A/Puerto Rico/8/34 (PR8), in which viral replication was inhibited by D35 at the late stage, with the NA gene from WSN, in which viral replication was not inhibited, eliminated the D35-dependent suppression. D35 showed an additive anti-influenza effect with oseltamivir. It was also effective in vivo. These results suggest that the influenza virus NA mainly contributse to the D35-suppressible virus release from infected cells at the late stage. In addition, because administration of D35 into the virus-infected mice suppressed viral replication and weight loss, clinical application of D35 could be considered. (C) 2016 Elsevier B.V. All rights reserved.
  • Kanae Shiokawa, Chandika D. Gamage, Nobuo Koizumi, Yoshihiro Sakoda, Kenta Shimizu, Yoshimi Tsuda, Kumiko Yoshimatsu, Jiro Arikawa
    JOURNAL OF VETERINARY MEDICAL SCIENCE 78 2 221 - 230 2016年02月 [査読有り][通常論文]
     
    The applicability of the recombinant LipL32 for serodiagnosis of leptospiral infection in field rodents was assessed in this study. An immunodominant region of LipL32 was determined by monoclonal antibodies, and then, truncated LipL32 (tLipL32) was designed to contain the region (87-188th amino acid). The tLipL32 was compared between two recombinant expression hosts Escherichia coli and Pichia pastoris in ELISA. With field rat sera, tLipL32 expressed by P. pastoris (tLipL32p) had high antigenicity without background reactions, while tLipL32 expressed by E. coli (tLipL32e) showed high background reactions, which were reduced by pre-adsorption of sera with E. coli. To evaluate tLipL32-ELISA, field rat sera were tentatively divided into a Leptospira infection positive (12 sera) and a negative group (12 sera) based on the results from flaB gene PCR of kidney samples and WB with whole Leptospira cell. Consequently, the sensitivity of tLipL32p-ELISA for field rat sera was 83%. A similar result was obtained from tLipL32e-ELISA with adsorbed sera, (92%). However, sensitivity of tLipL32e-ELISA using sera without an adsorption treatment was 50%. Regardless of the expression host, tLipL32-ELISA had 100% specificity and sensitivity in experimentally infected laboratory rats. These results suggest that recombinant LipL32 expressed by P pastoris is more applicable for serodiagnosis in field rats due to a lack of background reaction.
  • Takahiro Hiono, Masatoshi Okamatsu, Manabu Igarashi, Ryan McBride, Robert P. de Vries, Wenjie Peng, James C. Paulson, Yoshihiro Sakoda, Hiroshi Kida
    ARCHIVES OF VIROLOGY 161 2 307 - 316 2016年02月 [査読有り][通常論文]
     
    Influenza viruses isolated from ducks are rarely able to infect chickens; it is therefore postulated that these viruses need to adapt in some way to be able to be transmitted to chickens in nature. Previous studies revealed that sialyl Lewis X (3'SLeX), which is fucosylated alpha 2,3 sialoside, was predominantly detected on the epithelial cells of the chicken trachea, whereas this glycan structure is not found in the duck intestinal tract. To clarify the mechanisms of the interspecies transmission of influenza viruses between ducks and chickens, we compared the receptor specificity of low-pathogenic avian influenza viruses isolated from these two species. Glycan-binding analysis of the recombinant hemagglutinin (HA) of a chicken influenza virus, A/chicken/Ibaraki/1/2005 (H5N2), revealed a binding preference to alpha 1,3 fucosylated sialosides. On the other hand, the HA of a duck influenza virus, A/duck/Mongolia/54/2001 (H5N2) (Dk/MNG), particularly bound to non-fucosylated alpha 2,3 sialosides such as 3'-sialyllactosamine (3'SLacNAc). Computational analysis along with binding analysis of the mutant HAs revealed that this glycan-binding specificity of the HA was determined by amino acid residues at positions 222 and 227. Inconsistent with the glycan-binding specificity of the recombinant HA protein, virions of Dk/MNG bound to both 3'SLacNAc and 3'SLeX. Glycan-binding analysis in the presence of a neuraminidase (NA) inhibitor revealed that the NA conferred binding to 3'SLeX to virions of Dk/MNG. The present results reveal the molecular basis of the interaction between fucosylated alpha 2,3 sialosides and influenza viruses.
  • Takahiro Hiono, Keita Matsuno, Kotaro Tuchiya, Zhifeng Lin, Masatoshi Okamatsu, Yoshihiro Sakoda
    Genome Announcements 4 5 2016年 [査読有り][通常論文]
     
    Here, we report the complete genome sequence of the avian paramyxovirus serotype 5 strain APMV-5/budgerigar/Japan/TI/75, which was determined using the Illumina MiSeq platform. The determined sequence shares 97% homology and similar genetic features with the previously known genome sequence of avian paramyxovirus serotype 5 strain APMV-5/budgerigar/Japan/Kunitachi/74.
  • Takahiro Hiono, Masatoshi Okamatsu, Naoki Yamamoto, Kohei Ogasawara, Mayumi Endo, Saya Kuribayashi, Shintaro Shichinohe, Yurie Motohashi, Duc-Huy Chu, Mizuho Suzuki, Takaya Ichikawa, Tatsuya Nishi, Yuri Abe, Keita Matsuno, Kazuyuki Tanaka, Tsutomu Tanigawa, Hiroshi Kida, Yoshihiro Sakoda
    VETERINARY MICROBIOLOGY 182 108 - 115 2016年01月 [査読有り][通常論文]
     
    Highly pathogenic avian influenza viruses (HPAIVs) have spread in both poultry and wild birds. Determining transmission routes of these viruses during an outbreak is essential for the control of avian influenza. It has been widely postulated that migratory ducks play crucial roles in the widespread dissemination of HPAIVs in poultry by carrying viruses along with their migrations; however close contacts between wild migratory ducks and poultry are less likely in modern industrial poultry farming settings. Therefore, we conducted experimental infections of HPAIVs and low pathogenic avian influenza viruses (LPAIVs) to chickens, domestic ducks, tree sparrows, jungle crows, and black rats to evaluate their roles in virus transmission. The results showed that chickens, ducks, sparrows, and crows were highly susceptible to HPAIV infection. Significant titers of virus were recovered from the sparrows and crows infected with HPAIVs, which suggests that they potentially play roles of transmission of HPAIVs to poultry. In contrast, the growth of LPAIVs was limited in each of the animals tested compared with that of HPAIVs. The present results indicate that these common synanthropes play some roles in influenza virus transmission from wild birds to poultry. (C) 2015 Elsevier B.V. All rights reserved.
  • Yuri Abe, Tomokazu Tamura, Shiho Torii, Shiho Wakamori, Makoto Nagai, Kazuya Mitsuhashi, Junki Mine, Yuri Fujimoto, Naofumi Nagashima, Fumi Yoshino, Yukihiko Sugita, Takushi Nomura, Masatoshi Okamatsu, Hiroshi Kida, Yoshihiro Sakoda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 78 1 61 - 70 2016年01月 [査読有り][通常論文]
     
    In our previous study, we genetically analyzed bovine viral diarrhea viruses (BVDVs) isolated from 2000 to 2006 in Japan and reported that subgenotype 1b viruses were predominant. In the present study, 766 BVDVs isolated from 2006 to 2014 in Hokkaido, Japan, were genetically analyzed to understand recent epidemics. Phylogenetic analysis based on nucleotide sequences of the 5'-untranslated region of viral genome revealed that 766 isolates were classified as genotype 1 (BVDV-1; 544 isolates) and genotype 2 (BVDV-2; 222). BVDV-1 isolates were further divided into BVDV-la (93), 1b (371) and 1c (80) subgenotypes, and all BVDV-2 isolates were grouped into BVDV-2a subgenotype (222). Further comparative analysis was performed with BVDV-1a, 1b and 2a viruses isolated from 2001 to 2014. Phylogenetic analysis based on nucleotide sequences of the viral glycoprotein E2 gene, a major target of neutralizing antibodies, revealed that BVDV-1a, 1b and 2a isolates were further classified into several clusters. Cross-neutralization tests showed that BVDV-1b isolates were antigenically different from BVDV-1a isolates, and almost BVDV-1a, 1b and 2a isolates were antigenically similar among each subgenotype and each E2 cluster. Taken together, BVDV-1b viruses are still predominant, and BVDV-2a viruses have increased recently in Hokkaido, Japan. Field isolates of BVDV-1a, 1b and 2a show genetic diversity on the E2 gene with antigenic conservation among each subgenotype during the last 14 years.
  • Koichiro Gamoh, Mari Nakamizo, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Shoko Suzuki
    JOURNAL OF VETERINARY MEDICAL SCIENCE 78 1 139 - 142 2016年01月 [査読有り][通常論文]
     
    H5 highly pathogenic avian influenza (HPAI) viruses have spread worldwide, and antigenic variants of different clades have been selected. In this study, the national stockpiled vaccine prepared from A/duck/HoldcaidoNac-1/2004 (H5N1) strain was evaluated for the protective efficacy against H5N8 HPAI virus isolated in Kumamoto prefecture, Japan, in April 2014. In the challenge test, all of the vaccinated chickens survived without showing any clinical signs and reduced virus shedding. It was concluded that the present stockpiled vaccine was effective against the H5N8 HPAI virus.
  • Intracellular membrane association of classical swine fever virus NS4B is critical for viral RNA replication
    Tomokazu Tamura, Nicolas Ruggli, Masatoshi Okamatsu, Keita Matsuno, Yoshihiro Sakoda
    2015年11月 [査読有り][通常論文]
  • 豚コレラウイルスの病原性発現の分子基盤
    田村友和, Nicolas Ruggli, 岡松正敏, 松野啓太, 迫田義博
    2015年11月 [査読有り][通常論文]
  • Apolipoproteins and viral secretory glycoproteins participate in the infectious particle formation of Flaviviridae
    Takasuke Fukuhara, Tomokazu Tamura, Mai Shiokawa, Chikako Ono, Satomi Yamamoto, Hiroyuki Mori, Takeshi Kurihara, Toru Okamoto, Hiroshi Aoki, Yoshihiro Sakoda, Yoshiharu Matsuura
    2015年11月 [査読有り][通常論文]
  • フラビウイルス科に共通した小胞体膜結合因子を介した粒子産生機構の解析
    福原 崇介, 田村 友和, 塩川 舞, 小野 慎子, 山本 聡美, 森 寛行, 栗原 健, 岡本 徹, 青木 博史, 迫田 義博, 松浦 善治
    2015年11月 [査読有り][通常論文]
  • Host or virus derived secretory membrane binding proteins are involved in formation of infectious Flavivirus particles
    Takasuke Fukuhara, Tomokazu Tamura, Mai Shiokawa, Chikako Ono, Satomi Yamamoto, Hiroyuki Mori, Takeshi Kurihara, Puig-Basagoiti Francesc, Toru Okamoto, Hiroshi Aoki, Yoshihiro Sakoda, Yoshiharu Matsuura
    2015年11月 [査読有り][通常論文]
  • Naganori Nao, Masahiro Kajihara, Rashid Manzoor, Junki Maruyama, Reiko Yoshida, Mieko Muramatsu, Hiroko Miyamoto, Manabu Igarashi, Nao Eguchi, Masahiro Sato, Tatsunari Kondoh, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Ayato Takada
    PLOS ONE 10 9 e0137989  2015年09月 [査読有り][通常論文]
     
    Two highly pathogenic avian influenza virus strains, A/duck/Hokkaido/WZ83/2010 ( H5N1) (WZ83) and A/duck/Hokkaido/WZ101/2010 (H5N1) (WZ101), which were isolated from wild ducks in Japan, were found to be genetically similar, with only two amino acid differences in their M1 and PB1 proteins at positions 43 and 317, respectively. We found that both WZ83 and WZ101 caused lethal infection in chickens but WZ101 killed them more rapidly than WZ83. Interestingly, ducks experimentally infected with WZ83 showed no or only mild clinical symptoms, whereas WZ101 was highly lethal. We then generated reassortants between these viruses and found that exchange of the M gene segment completely switched the pathogenic phenotype in both chickens and ducks, indicating that the difference in the pathogenicity for these avian species between WZ83 and WZ101 was determined by only a single amino acid in the M1 protein. It was also found that WZ101 showed higher pathogenicity than WZ83 in mice and that WZ83, whose M gene was replaced with that of WZ101, showed higher pathogenicity than wild-type WZ83, although this reassortant virus was not fully pathogenic compared to wild-type WZ101. These results suggest that the amino acid at position 43 of the M1 protein is one of the factors contributing to the pathogenicity of H5N1 highly pathogenic avian influenza viruses in both avian and mammalian hosts.
  • Tomokazu Tamura, Nicolas Ruggli, Naofumi Nagashima, Masatoshi Okamatsu, Manabu Igarashi, Junki Mine, Martin A. Hofmann, Matthias Liniger, Artur Summerfield, Hiroshi Kida, Yoshihiro Sakoda
    JOURNAL OF GENERAL VIROLOGY 96 9 2623 - 2635 2015年09月 [査読有り][通常論文]
     
    Classical swine fever virus (CSFV) causes a highly contagious disease in pigs that can range from a severe haemorrhagic fever to a nearly unapparent disease, depending on the virulence of the virus strain. Little is known about the viral molecular determinants of CSFV virulence. The nonstructural protein NS4B is essential for viral replication. However, the roles of CSFV NS4B in viral genome replication and pathogenesis have not yet been elucidated. NS4B of the GPE(-) vaccine strain and of the highly virulent Eystrup strain differ by a total of seven amino acid residues, two of which are located in the predicted trans-membrane domains of NS4B and were described previously to relate to virulence, and five residues clustering in the N-terminal part. In the present study, we examined the potential role of these five amino acids in modulating genome replication and determining pathogenicity in pigs. A chimeric low virulent GPE(-)-derived virus carrying the complete Eystrup NS4B showed enhanced pathogenicity in pigs. The in vitro replication efficiency of the NS4B chimeric GPE- replicon was significantly higher than that of the replicon carrying only the two Eystrup-specific amino acids in NS4B. In silico and in vitro data suggest that the N-terminal part of NS4B forms an amphipathic a-helix structure. The N-terminal NS4B with these five amino acid residues is associated with the intracellular membranes. Taken together, this is the first gain-of-function study showing that the N-terminal domain of NS4B can determine CSFV genome replication in cell culture and viral pathogenicity in pigs.
  • Takahiro Hiono, Ayako Ohkawara, Kohei Ogasawara, Masatoshi Okamatsu, Tomokazu Tamura, Duc-Huy Chu, Mizuho Suzuki, Saya Kuribayashi, Shintaro Shichinohe, Ayato Takada, Hirohito Ogawa, Reiko Yoshida, Hiroko Miyamoto, Naganori Nao, Wakako Furuyama, Junki Maruyama, Nao Eguchi, Gerelmaa Ulziibat, Bazarragchaa Enkhbold, Munkhduuren Shatar, Tserenjav Jargalsaikhan, Selenge Byambadorj, Batchuluun Damdinjav, Yoshihiro Sakoda, Hiroshi Kida
    VIRUS GENES 51 1 57 - 68 2015年08月 [査読有り][通常論文]
     
    Migratory water birds are the natural reservoir of influenza A viruses. H5 and H7 influenza viruses are isolated over the world and also circulate among poultry in Asia. In 2010, two H5N1 highly pathogenic avian influenza viruses (HPAIVs) were isolated from fecal samples of water birds on the flyway of migration from Siberia, Russia to the south in Hokkaido, Japan. H7N9 viruses are sporadically isolated from humans and circulate in poultry in China. To monitor whether these viruses have spread in the wild bird population, we conducted virological surveillance of avian influenza in migratory water birds in autumn from 2010 to 2014. A total of 8103 fecal samples from migratory water birds were collected in Japan and Mongolia, and 350 influenza viruses including 13 H5 and 19 H7 influenza viruses were isolated. A phylogenetic analysis revealed that all isolates are genetically closely related to viruses circulating among wild water birds. The results of the antigenic analysis indicated that the antigenicity of viruses in wild water birds is highly stable despite their nucleotide sequence diversity but is distinct from that of HPAIVs recently isolated in Asia. The present results suggest that HPAIVs and Chinese H7N9 viruses were not predominantly circulating in migratory water birds; however, continued monitoring of H5 and H7 influenza viruses both in domestic and wild birds is recommended for the control of avian influenza.
  • Yasushi Itoh, Shintaro Shichinohe, Misako Nakayama, Manabu Igarashi, Akihiro Ishii, Hirohito Ishigaki, Hideaki Ishida, Naoko Kitagawa, Takako Sasamura, Masanori Shiohara, Michiko Doi, Hideaki Tsuchiya, Shinichiro Nakamura, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Kazumasa Ogasawara
    ANTIMICROBIAL AGENTS AND CHEMOTHERAPY 59 8 4962 - 4973 2015年08月 [査読有り][通常論文]
     
    The number of patients infected with H7N9 influenza virus has been increasing since 2013. We examined the efficacy of neuraminidase (NA) inhibitors and the efficacy of a vaccine against an H7N9 influenza virus, A/Anhui/1/2013 (H7N9), isolated from a patient in a cynomolgus macaque model. NA inhibitors (oseltamivir and peramivir) barely reduced the total virus amount because of the emergence of resistant variants with R289K or 1219T in NA [residues 289 and 219 in N9 of A/Anhui/1/2013 (H7N9) correspond to 292 and 222 in N2, respectively] in three of the six treated macaques, whereas subcutaneous immunization of an inactivated vaccine derived from A/duck/Mongolia/119/2008 (H7N9) prevented propagation of A/Anhui/1/2013 (H7N9) in all vaccinated macaques. The percentage of macaques in which variant H7N9 viruses with low sensitivity to the NA inhibitors were detected was much higher than that of macaques in which variant H5N1 highly pathogenic influenza virus was detected after treatment with one of the NA inhibitors in our previous study. The virus with R289K in NA was reported in samples from human patients, whereas that with 1219T in NA was identified for the first time in this study using macaques, though no variant H7N9 virus was reported in previous studies using mice. Therefore, the macaque model enables prediction of the frequency of emerging H7N9 virus resistant to NA inhibitors in vivo. Since H7N9 strains resistant to NA inhibitors might easily emerge compared to other influenza viruses, monitoring of the emergence of variants is required during treatment of H7N9 influenza virus infection with NA inhibitors.
  • 豚コレラウイルス非構造蛋白NS4Bの機能と病原性に及ぼす影響
    田村友和, Nicolas Ruggli, 長島尚史, 岡松正敏, Artur Summerfield, 松野啓太, 喜田宏, 迫田義博
    2015年07月 [査読有り][通常論文]
  • Junki Mine, Tomokazu Tamura, Kazuya Mitsuhashi, Masatoshi Okamatsu, Sujira Parchariyanon, Wasana Pinyochon, Nicolas Ruggli, Jon-Duri Tratschin, Hiroshi Kida, Yoshihiro Sakoda
    JOURNAL OF GENERAL VIROLOGY 96 7 1746 - 1756 2015年07月 [査読有り][通常論文]
     
    The viral protein N-pro is unique to the genus Pestivirus within the family Flaviviridae. After autocatalytic cleavage from the nascent polyprotein, N-pro suppresses type I IFN (IFN-alpha/beta) induction by mediating proteasomal degradation of IFN regulatory factor 3 (IRF-3). Previous studies found that the N-pro-mediated IRF-3 degradation was dependent of a TRASH domain in the C-terminal half of N-pro coordinating zinc by means of the amino acid residues 0112, 0134, D136 and C138. Interestingly, four classical swine fever virus (CSFV) isolates obtained from diseased pigs in Thailand in 1993 and 1998 did not suppress IFN-alpha/beta induction despite the presence of an intact TRASH domain. Through systematic analyses, it was found that an amino acid mutation at position 40 or mutations at positions 17 and 61 in the N-terminal half of N-pro of these four isolates were related to the lack of IRF-3-degrading activity. restoring a histidine at position 40 or both a proline at position 17 and a lysine at position 61 based on the sequence of a functional N-pro contributed to higher stability of the reconstructed N-pro compared with the N-pro from the Thai isolate. This led to enhanced interaction of N-pro with IRF-3 along with its degradation by the proteasome. The results of the present study revealed that amino acid residues in the N-terminal domain of N-pro are involved in the stability of N-pro, in interaction of N-pro with IRF-3 and subsequent degradation of IRF-3, leading to downregulation of IFN-alpha/beta production.
  • VIRAL GENETIC DETERMINANTS OF CLASSICAL SWINE FEVER VIRUS VIRULENCE
    Tomokazu Tamura, Nicolas Ruggli, Naofumi Nagashima, Masatoshi Okamatsu, Martin A. Hofmann, Hiroshi Kida, Autur Summerfield, Yoshihiro Sakoda
    2015年06月 [査読有り][通常論文]
  • Takashi Kozasa, Yuri Abe, Kazuya Mitsuhashi, Tomokazu Tamura, Hiroshi Aoki, Masatoshi Ishimaru, Shigeyuki Nakamura, Masatoshi Okamatsu, Hiroshi Kida, Yoshihiro Sakoda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 77 5 511 - 518 2015年05月 [査読有り][通常論文]
     
    The Exaltation of Newcastle disease virus (END) phenomenon is induced by the inhibition of type I interferon in pestivirus-infected cells in vitro, via proteasomal degradation of cellular interferon regulatory factor (IRF)-3 with the property of the viral autoprotease protein N-pro. Reportedly, the amino acid residues in the zinc-binding TRASH motif of N-pro determine the difference in characteristics between END-phenomenon-positive (END) and END-phenomenon-negative (END-) classical swine fever viruses (CSFVs). However, the basic mechanism underlying this function in bovine viral diarrhea virus (BVDV) has not been elucidated from the genomic differences between END+ and END- viruses using reverse genetics till date. In the present study, comparison of complete genome sequences of a pair of END+ and END- viruses isolated from the same virus stock revealed that there were only four amino acid substitutions (D136G, I2623V, D3148G and D3502Y) between two viruses. Based on these differences, viruses with and without mutations at these positions were generated using reverse genetics. The END assay, measurements of induced type I interferon and IRF-3 detection in cells infected with these viruses revealed that the aspartic acid at position 136 in the zinc-binding TRASH motif of N-pro was required to inhibit the production of type I interferon via the degradation of cellular IRF-3, consistently with CSFV.
  • Tomokazu Tamura, Junki Mine, Shiho Torii, Yuri Fujimoto, Masatoshi Okamatsu, Yoshihiro Sakoda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 77 3 341 - 343 2015年03月 [査読有り][通常論文]
     
    A first isolation of border disease virus (BDV) in Japan was from a pig on a farm without keeping any ruminants. Our previous study showed that this BDV, termed the FNK2012-1 strain, replicated inefficiently in swine-derived cells compared with those of ruminant origin. Pigs inoculated with this virus showed neither clinical symptoms nor viremia. In this study, we evaluated the pathogenicity of the FNK2012-1 strain in sheep, its natural host. The inoculated sheep showed clinical symptoms and transient viremia. Seroconversion was observed in the inoculated sheep. These results suggest that the FNK2012-1 strain was introduced from sheep and has not yet adapted to swine. Therefore, surveillance of border disease in Japan is necessary among both the swine and ruminant populations.
  • Akira Sakurai, Katsuyoshi Takayama, Namiko Nomura, Naoki Kajiwara, Masatoshi Okamatsu, Naoki Yamamoto, Tsuruki Tamura, Jitsuho Yamada, Masako Hashimoto, Yoshihiro Sakoda, Yoshihiko Suda, Yukuharu Kobayashi, Hiroshi Kida, Futoshi Shibasaki
    PLOS ONE 10 2 e0116715  2015年02月 [査読有り][通常論文]
     
    Lateral flow tests also known as Immunochromatography (IC) is an antigen-detection method conducted on a nitrocellulose membrane that can be completed in less than 20 min. IC has been used as an important rapid test for clinical diagnosis and surveillance of influenza viruses, but the IC sensitivity is relatively low (approximately 60%) and the limit of detection (LOD) is as low as 10(3) pfu per reaction. Recently, we reported an improved IC assay using antibodies conjugated with fluorescent beads (fluorescent immunochromatography; FLIC) for subtyping H5 influenza viruses (FLIC-H5). Although the FLIC strip must be scanned using a fluorescent reader, the sensitivity (LOD) is significantly improved over that of conventional IC methods. In addition, the antibodies which are specific against the subtypes of influenza viruses cannot be available for the detection of other subtypes when the major antigenicity will be changed. In this study, we established the use of FLIC to type seasonal influenza A and B viruses (FLIC-AB). This method has improved sensitivity to 100-fold higher than that of conventional IC methods when we used several strains of influenza viruses. In addition, FLIC-AB demonstrated the ability to detect influenza type A and influenza type B viruses from clinical samples with high sensitivity and specificity (Type A: sensitivity 98.7% (74/75), specificity 100% (54/54), Type B: sensitivity 100% (90/90), specificity 98.2% (54/55) in nasal swab samples) in comparison to the results of qRT-PCR. And furthermore, FLIC-AB performs better in the detection of early stage infection (under 13h) than other conventional IC methods. Our results provide new strategies to prevent the early-stage transmission of influenza viruses in humans during both seasonal outbreaks and pandemics.
  • Kaoru Nishine, Hiroshi Aoki, Yoshihiro Sakoda, Akio Fukusho
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76 12 1635 - 1639 2014年12月 [査読有り][通常論文]
     
    Field isolates of BVDV which do not show the exaltation of Newcastle disease virus (END) phenomenon (END-) are rarely reported. In this study, 45 BVDV field isolates from cattle in Hokkaido prefecture in Japan were analyzed by the reverse plaque formation method, the END method and observation of cytopathic effects. END- virus was detected in 34 of 45 isolates (75.6%), although 35 of 45 field isolates contained END phenomenon positive virus as the predominant virus population. We propose that END- viruses are widely distributed in the field and that it is possible that the mixture of biologically distinct BVDV correlates with the appearance of disease in infected animals.
  • Kaoru Nishine, Hiroshi Aoki, Yoshihiro Sakoda, Akio Fukusho
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76 12 1635 - 1639 2014年12月 [査読有り][通常論文]
     
    Field isolates of BVDV which do not show the exaltation of Newcastle disease virus (END) phenomenon (END-) are rarely reported. In this study, 45 BVDV field isolates from cattle in Hokkaido prefecture in Japan were analyzed by the reverse plaque formation method, the END method and observation of cytopathic effects. END- virus was detected in 34 of 45 isolates (75.6%), although 35 of 45 field isolates contained END phenomenon positive virus as the predominant virus population. We propose that END- viruses are widely distributed in the field and that it is possible that the mixture of biologically distinct BVDV correlates with the appearance of disease in infected animals.
  • Akira Sakurai, Katsuyoshi Takayama, Namiko Nomura, Naoki Yamamoto, Yoshihiro Sakoda, Yukuharu Kobayashi, Hiroshi Kida, Futoshi Shibasaki
    JOURNAL OF VIROLOGICAL METHODS 209 62 - 68 2014年12月 [査読有り][通常論文]
     
    Immunochromatography (IC) is an antigen-detection assay that plays an important role in the rapid diagnosis of influenza viruses because of its rapid turnaround and ease of use. Despite the usefulness of IC, the limit of detection of common IC kits is as high as 10(3)-10(4) plaque forming units (pfu) per reaction, resulting in their limited sensitivities. Early diagnosis within 24 h would provide more appropriate timing of treatment. In this study, a multi-colored NanoAct(TM) bead IC was established to detect seasonal influenza viruses. This method has approximately 10-fold higher sensitivity than that of colloidal gold or colored latex bead IC assays, and does not require specific instruments. More notably, NanoAct(Tm) bead IC can distinguish influenza A and B viruses from clinical samples with a straightforward readout composed of colored lines. Our results will provide new strategies for the diagnosis, treatment, and a chance to survey of influenza viruses in developing countries and in the field research. (C) 2014 Elsevier B.V. All rights reserved.
  • Ahmad M. Haredy, Hiroshi Yamada, Yoshihiro Sakoda, Masatoshi Okamatsu, Naoki Yamamoto, Takeshi Omasa, Yasuko Mori, Hiroshi Kida, Shigefumi Okamoto, Yoshinobu Okuno, Koichi Yamanishi
    JOURNAL OF GENERAL VIROLOGY 95 Pt 11 2365 - 2371 2014年11月 [査読有り][通常論文]
     
    Whole-virus (WV) vaccines from influenza A/duck/Hokkaido/77 (H3N2), and its reassortant strains H3N4, H3N5 and H3N7, which have the same haemagglutinin (HA) gene but different neuraminidase (NA) genes, were prepared from our influenza virus library. Mice were intranasally immunized with equivalent doses of each vaccine (1-0.01 mu g per mouse). All of the mice that received the highest dose of each vaccine (1 mu g per mouse) showed equivalent high HA-inhibiting (HI) antibody titres and survived the H3N2 challenge viruses. However, mice that received lower doses of vaccine (0.1 or 0.01 mu g per mouse) containing a heterologous NA had lower survival rates than those given the H3N2-based vaccine. The lungs of mice challenged with H3N2 virus showed a significantly higher virus clearance rate when the vaccine contained the homologous NA (N2) versus a heterologous NA, suggesting that NA contributed to the protection, especially when the HI antibody level was low. These results suggested that, even if vaccines prepared for a possible upcoming pandemic do not induce sufficient HI antibodies, WV vaccines can still be effective through other matched proteins such as NA.
  • Tatsuya Nishi, Yoshihiro Sakoda, Masatoshi Okamatsu, Hiroshi Kida
    ARCHIVES OF VIROLOGY 159 10 2567 - 2574 2014年10月 [査読有り][通常論文]
     
    H6 influenza viruses are prevalent in domestic and wild birds in Eurasian countries and have been isolated from pigs and a human. To prepare for an influenza pandemic, we have established an influenza virus library consisting of more than 1,300 influenza virus strains, including 144 combinations of 16 hemagglutinin and 9 neuraminidase subtypes. H6 viruses in the library were classified into Early, Group II, Group III, and W312 sublineages and the North America lineage on the basis of their phylogenetic features. Chicken antisera to A/duck/Hong Kong/960/1980 (H6N2) of the Early sublineage broadly reacted with viruses of different sublineages in a hemagglutinin inhibition test. A whole inactivated virus particle vaccine was prepared from A/duck/Hong Kong/960/1980 (H6N2) which was stocked in the influenza virus library. The potency of this vaccine against A/duck/Vietnam/OIE-0033/2012 (H6N2), which belongs to a different sublineage, was evaluated in mice. The test vaccine was sufficiently potent to induce an immune response that reduced the impact of disease caused by a challenge with A/duck/Vietnam/OIE-0033/2012 (H6N2) in mice. The present results indicate that the whole inactivated virus particle vaccine prepared from a virus strain in the influenza virus library is useful as a vaccine against pandemic influenza.
  • Takuji Kumagai, Tetsuo Nakayama, Yoshinobu Okuno, Tetsuo Kase, Naoko Nishimura, Takao Ozaki, Akiko Miyata, Eitaro Suzuki, Teruo Okafuji, Takao Okafuji, Hitoshi Ochiai, Nobuo Nagata, Hiroyuki Tsutsumi, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Toshiaki Ihara
    VIRAL IMMUNOLOGY 27 8 368 - 374 2014年10月 [査読有り][通常論文]
     
    The 2009 pandemic H1N1 mainly affected adolescents and children, and most of the elderly in Japan escaped clinical illness. To clarify the role of humoral immunity in the infection, the time kinetics of hemagglutination inhibition (HI), neutralization (NT), and IgG subclass antibody response directed against influenza A(H1N1)pdm2009 were analyzed in three consecutive specimens obtained from 51 young adults and children (group 1) who contracted pandemic influenza and from 74 pediatric clinic employees (group 2) inoculated with pandemic monovalent vaccine. In group 1 patients, 6 and 30 patients had lower HI and NT antibody in the acute phase respectively. Thereafter, HI and NT antibody titers increased fourfold or more in 50 patients with peak response in the third specimens obtained four weeks after the onset. IgG1 in 45 patients, IgG3 in 18 patients, and IgG4 in 29 patients showed elevated responses. Forty (54%) and 70 (95%) subjects in group 2 had positive HI and NT antibodies in the prevaccination samples, with increased antibody responses in the follow-up peaking in the second specimens. Forty of those vaccinated had increased IgG1 responses peaking in the third specimens, whereas elevated IgG3 was observed in 22 recipients with the highest level in the second samples. IgG4 did not show any increase in subjects in group 2. A few participants showed an IgG2 response in both groups. An immunologically naive population contracted influenza with apparent clinical symptoms. However, already primed subjects through subclinical infection elicited the unique pattern of IgG subclass responses by vaccination, which differed from those of naive populations.
  • Makoto Kodama, Ryu Yoshida, Takahiro Hasegawa, Masaaki Izawa, Mitsutaka Kitano, Kaoru Baba, Takeshi Noshi, Takahiro Seki, Kenichi Okazaki, Masakatsu Tsuji, Takushi Kanazu, Hiroshi Kamimori, Tomoyuki Homma, Masanori Kobayashi, Yoshihiro Sakoda, Hiroshi Kida, Akihiko Sato, Yoshinori Yamano
    ANTIVIRAL RESEARCH 109 110 - 115 2014年09月 [査読有り][通常論文]
     
    The purpose of this study was to investigate the relationship between pharmacokinetic (PK) parameters of intravenous (IV) peramivir and in vivo antiviral activity pharmacodynamic (PD) outcomes in a mouse model of influenza virus infection. Peramivir was administrated to mice in three dosing schedules; once, twice and four times after infection of A/WS/33 (H1N1). The survival rate at day 14 after virus infection was employed as the antiviral activity outcome for analysis. The relationship between day 14 survival and PK parameters, including area under the concentration-time curve (AUC), maximum concentration (C-max) and time that drug concentration exceeds IC95 (T>(IC95)), was estimated using a logistic regression model, and model fitness was evaluated by calculation of the Akaike information criterion (AIC) index. The AIC indices of AUC, C-max and T->IC95 were about 114, 151 and 124, respectively. The AIC of AUC and T->IC95 were smaller than that of C-max. Therefore, both AUC and T->IC95 were the PK parameters that correlated best with the antiviral activity of peramivir IV against influenza virus infection in mice. (C) 2014 Elsevier B.V. All rights reserved.
  • Walied Abdo, Mohie Haridy, Yuki Katou, Minami Goto, Toshio Mizoguchi, Yoshihiro Sakoda, Hiroki Sakai, Tokuma Yanai
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76 9 1285 - 1290 2014年09月 [査読有り][通常論文]
     
    In the winter of 2010-2011, an outbreak of highly pathogenic avian influenza virus (HPAIV) infection occurred in wild and domestic birds in Japan. Tufted ducks were found dead in an urban area of Toyota City, Koriyama, Fukushima Prefecture. Two tufted ducks were examined histopathologically, immunohistochemically and molecularly. Gross findings included marked dark-red clotted blood in the pectoral muscles and multifocal hemorrhages on the serous membranes. Microscopically, non-suppurative meningoencephalitis, multifocal to coalescing pancreatic necrosis and severe pulmonary congestion were observed. HPAIV antigen was detected in the malacic areas, neuronal, glial and ependymal cells, pulmonary capillary endothelial cells and epithelium of pulmonary bronchioles, necrotic pancreatic acini and degenerated cardiac myocytes. The HPAIV isolate was genetically classified into clade 2.3.2.1 group A. The broad distribution of virus antigen in brain and pulmonary tissues associated with HPAIV spontaneous infection in tufted ducks might be useful in understanding its pathogenesis in nature.
  • Makoto Nagai, Hiroshi Aoki, Yoshihiro Sakoda, Takashi Kozasa, Kaho Tominaga-Teshima, Junki Mine, Yuri Abe, Tomokazu Tamura, Tsubasa Kobayashi, Kaoru Nishine, Kentaro Tateishi, Yudai Suzuki, Mai Fukuhara, Keitaro Ohmori, Reiko Todaka, Kazuhiko Katayama, Tetsuya Mizutani, Shigeyuki Nakamura, Hiroshi Kida, Junsuke Shirai
    JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION 26 4 547 - 552 2014年07月 [査読有り][通常論文]
     
    In the current study, molecular, biological, and antigenic analyses were performed to characterize Border disease virus (BDV) strain FNK2012-1 isolated from a pig in 2012 in Japan. The complete genome comprises 12,327 nucleotides (nt), including a large open reading frame of 11,685 nt. Phylogenetic analysis revealed that FNK2012-1 was clustered into BDV genotype 1 with ovine strains. FNK2012-1 grew in porcine, bovine, and ovine primary cells and cell lines, but grew better in bovine and ovine cells than in porcine cells. Specific pathogen-free pigs inoculated with FNK2012-1 did not show any clinical signs. Noninoculated contact control pigs also did not show clinical signs and did not seroconvert. The results suggest that FNK2012-1 may be of ruminant origin and is poorly adapted to pigs. Such observations can provide important insights into evidence for infection and transmission of BDV, which may be of ruminant origin, among pigs.
  • Duc-Huy Chu, Yoshihiro Sakoda, Tatsuya Nishi, Takahiro Hiono, Shintaro Shichinohe, Masatoshi Okamatsu, Hiroshi Kida
    VACCINE 32 28 3473 - 3479 2014年06月 [査読有り][通常論文]
     
    H7N9 influenza virus infection in humans was reported in China on March 31, 2013. Humans are immunologically naive to the H7N9 subtype, for which the seasonal influenza vaccine is not effective. Thus, the development of an H7N9 influenza virus vaccine is an urgent issue. To prepare for the emergence of an influenza pandemic, we have established a library comprising more than 1300 influenza virus strains with 144 different combinations of 16 HA and 9 NA subtypes. An H7N9 virus strain isolated from a 35-year-old woman, A/Anhui/1/2013 (H7N9), was found to be antigenically similar to H7N9 influenza viruses isolated from migratory ducks. In the present study, the potency of an inactivated whole virus particle vaccine prepared from an H7N9 low pathogenic avian influenza virus, A/duck/Mongolia/119/2008 (H7N9), selected from the library, was assessed by a challenge with A/Anhui/1/2013 (H7N9). The results indicate that the test vaccine was potent enough to induce sufficient immunity to reduce the impact of disease caused by the challenge with A/Anhui/1/2013 (H7N9) in mice. The present results indicate that an inactivated whole virus particle vaccine prepared from an influenza virus strain stored in the library could be useful as a vaccine strain in case of an influenza pandemic. (C) 2014 Published by Elsevier Ltd.
  • Yasushi Itoh, Reiko Yoshida, Shintaro Shichinohe, Megumi Higuchi, Hirohito Ishigaki, Misako Nakayama, Van Loi Pham, Hideaki Ishida, Mitsutaka Kitano, Masahiko Arikata, Naoko Kitagawa, Yachiyo Mitsuishi, Kazumasa Ogasawara, Hideaki Tsuchiya, Takahiro Hiono, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Mutsumi Ito, Le Quynh Mai, Yoshihiro Kawaoka, Hiroko Miyamoto, Mari Ishijima, Manabu Igarashi, Yasuhiko Suzuki, Ayato Takada
    PLOS PATHOGENS 10 6 e1004192  2014年06月 [査読有り][通常論文]
     
    Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype often cause severe pneumonia and multiple organ failure in humans, with reported case fatality rates of more than 60%. To develop a clinical antibody therapy, we generated a human-mouse chimeric monoclonal antibody (MAb) ch61 that showed strong neutralizing activity against H5N1 HPAI viruses isolated from humans and evaluated its protective potential in mouse and nonhuman primate models of H5N1 HPAI virus infections. Passive immunization with MAb ch61 one day before or after challenge with a lethal dose of the virus completely protected mice, and partial protection was achieved when mice were treated 3 days after the challenge. In a cynomolgus macaque model, reduced viral loads and partial protection against lethal infection were observed in macaques treated with MAb ch61 intravenously one and three days after challenge. Protective effects were also noted in macaques under immunosuppression. Though mutant viruses escaping from neutralization by MAb ch61 were recovered from macaques treated with this MAb alone, combined treatment with MAb ch61 and peramivir reduced the emergence of escape mutants. Our results indicate that antibody therapy might be beneficial in reducing viral loads and delaying disease progression during H5N1 HPAI virus infection in clinical cases and combined treatment with other antiviral compounds should improve the protective effects of antibody therapy against H5N1 HPAI virus infection.
  • Hiono T, Okamatsu M, Nishihara S, Takase-Yoden S, Sakoda Y, Kida H
    Virology 456 131 - 138 2014年05月 [査読有り][通常論文]
     
    Influenza viruses recognize sialoglycans as receptors. Although viruses isolated form chickens preferentially bind to sialic acid alpha 2,3 galactose (SA alpha 2,3Gal) glycans as do those of ducks, chickens were not experimentally infected with viruses isolated from ducks. A chicken influenza virus, A/chicken/Ibaraki/1/ 2005 (H5N2) (Ck/IBR) bound to fucose-branched SAa2,3Gal glycans, whereas the binding towards linear SAa2,3Gal glycans was weak. On the epithelial cells of the upper respiratory tracts of chickens, fucose-branched SA alpha 2,3Gal glycans were detected, but not linear SA alpha 2,3Gal glycans. The growth of Ck/IBR in MDCK-FUT cells, which were genetically prepared to express fucose-branched SA alpha 2,3Gal glycans, was significantly higher than that in the parental MDCK cells. The present results indicate that fucosebranched SA alpha 2,3Gal glycans existing on the epithelial cells lining the upper respiratory tracts of chickens are critical for recognition by Ck/IBR. (c) 2014 Elsevier Inc. All rights reserved.
  • Tomokazu Tamura, Naofumi Nagashima, Nicolas Ruggli, Artur Summerfield, Hiroshi Kida, Yoshihiro Sakoda
    VETERINARY RESEARCH 45 47  2014年04月 [査読有り][通常論文]
     
    Classical swine fever (CSF) caused by CSF virus (CSFV) is a highly contagious disease of pigs. The viral protein N-pro of CSFV interferes with alpha-and beta-interferon (IFN-alpha/beta) induction by promoting the degradation of interferon regulatory factor 3 (IRF3). During the establishment of the live attenuated CSF vaccine strain GPE(-), N-pro acquired a mutation that abolished its capacity to bind and degrade IRF3, rendering it unable to prevent IFN-alpha/beta induction. In a previous study, we showed that the GPE(-) vaccine virus became pathogenic after forced serial passages in pigs, which was attributed to the amino acid substitutions T830A in the viral proteins E2 and V2475A and A2563V in NS4B. Interestingly, during the re-adaptation of the GPE(-) vaccine virus in pigs, the IRF3-degrading function of N-pro was not recovered. Therefore, we examined whether restoring the ability of N-pro to block IFN-alpha/beta induction of both the avirulent and moderately virulent GPE(-)-derived virus would enhance pathogenicity in pigs. Viruses carrying the N136D substitution in N-pro regained the ability to degrade IRF3 and suppress IFN-alpha/beta induction in vitro. In pigs, functional N-pro significantly reduced the local IFN-alpha mRNA expression in lymphoid organs while it increased quantities of IFN-alpha/beta in the circulation, and enhanced pathogenicity of the moderately virulent virus. In conclusion, the present study demonstrates that functional N-pro influences the innate immune response at local sites of virus replication in pigs and contributes to pathogenicity of CSFV in synergy with viral replication.
  • Junki Maruyama, Hiroko Miyamoto, Masahiro Kajihara, Hirohito Ogawa, Ken Maeda, Yoshihiro Sakoda, Reiko Yoshida, Ayato Takada
    JOURNAL OF VIROLOGY 88 1 99 - 109 2014年01月 [査読有り][通常論文]
     
    Lloviu virus (LLOV), a novel filovirus detected in bats, is phylogenetically distinct from viruses in the genera Ebolavirus and Marburgvirus in the family Filoviridae. While filoviruses are known to cause severe hemorrhagic fever in humans and/or nonhuman primates, LLOV is biologically uncharacterized, since infectious LLOV has never been isolated. To examine the properties of LLOV, we characterized its envelope glycoprotein (GP), which likely plays a key role in viral tropism and pathogenicity. We first found that LLOV GP principally has the same primary structure as the other filovirus GPs. Similar to the other filoviruses, virus-like particles (VLPs) produced by transient expression of LLOV GP, matrix protein, and nucleoprotein in 293T cells had densely arrayed GP spikes on a filamentous particle. Mouse antiserum to LLOV VLP was barely cross-reactive to viruses of the other genera, indicating that LLOV is serologically distinct from the other known filoviruses. For functional study of LLOV GP, we utilized a vesicular stomatitis virus (VSV) pseudotype system and found that LLOV GP requires low endosomal pH and cathepsin L, and that human C-type lectins act as attachment factors for LLOV entry into cells. Interestingly, LLOV GP-pseudotyped VSV infected particular bat cell lines more efficiently than viruses bearing other filovirus GPs. These results suggest that LLOV GP mediates cellular entry in a manner similar to that of the other filoviruses while showing preferential tropism for some bat cells.
  • Haru Ogiwara, Fumihiko Yasui, Keisuke Munekata, Asako Takagi-Kamiya, Tsubasa Munakata, Namiko Nomura, Futoshi Shibasaki, Kazuhiko Kuwahara, Nobuo Sakaguchi, Yoshihiro Sakoda, Hiroshi Kida, Michinori Kohara
    AMERICAN JOURNAL OF PATHOLOGY 184 1 171 - 183 2014年01月 [査読有り][通常論文]
     
    Patients infected with highly pathogenic avian influenza A H5N1 viruses (H5N1 HPAIV) show diffuse alveolar damage. However, the temporal progression of tissue damage and repair after viral infection remains poorly defined. Therefore, we assessed the sequential histopathological characteristics of mouse lung after intranasal infection with H5N1 HPAIV or H1N1 2009 pandemic influenza virus (H1N1 pdm). We determined the amount and localization of virus in the Lung through IHC staining and in situ hybridization. IHC used antibodies raised against the virus protein and antibodies specific for macrophages, type II pneumocytes, or proliferating cell nuclear antigen. In situ hybridization used RNA probes against both viral RNA and mRNA encoding the nucleoprotein and the hemagglutinin protein. H5N1 HPAIV infection and replication were observed in multiple lung cell types and might result in rapid progression of lung injury. Both type II pneumocytes and macrophages proliferated after H5N1 HPAIV infection. However, the abundant macrophages failed to block the viral attack, and proliferation of type II pneumocytes failed to restore the damaged alveoli. In contrast, mice infected with H1N1 pdm exhibited modest proliferation of type II pneumocytes and macrophages and slight alveolar damage. These results suggest that the virulence of H5N1 HPAIV results from the wide range of cell tropism of the virus, excessive virus replication, and rapid development of diffuse alveolar damage.
  • Tatsuya Nishi, Masatoshi Okamatsu, Kenji Sakurai, Huy Due Chu, Long Pham Thanh, Long van Nguyen, Nam van Hoang, Diep Nguyen Thi, Yoshihiro Sakoda, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76 1 85 - 87 2014年01月 [査読有り][通常論文]
     
    In August 2012, A/chicken/Vietnam/OIE-2215/2012 (H5N2) was isolated from a chicken in a live bird market (LBM) in Northern Vietnam. Intravenous pathogenicity test revealed that this virus is highly pathogenic in chickens. The PA, HA, NP and M, PB2 and NA, and PB1 and NS genes of the isolate were phylogenetically closely related to those of A/duck/Vietnam/OIE-2202/2012 (H5N1) of Glade 2.3.2.1, A/chicken/Vietnam/OIE-1611/2012 (H9N2) and A/chicken/Vietnam/OIE-2468/2012 (H9N2), respectively. All of these viruses were isolated from birds in LBMs in the same province. These results indicate that A/chicken/Vietnam/OIE-2215/2012 (H5N2) is a genetic reassortant and that surveillance of avian influenza in LBMs and stamping out policy are essential for the eradication of highly pathogenic avian influenza viruses from Asia.
  • Misako Nakayama, Shintaro Shichinohe, Yasushi Itoh, Hirohito Ishigaki, Mitsutaka Kitano, Masahiko Arikata, Van Loi Pham, Hideaki Ishida, Naoko Kitagawa, Masatoshi Okamatsu, Yoshihiro Sakoda, Takaya Ichikawa, Hideaki Tsuchiya, Shinichiro Nakamura, Quynh Mai Le, Mutsumi Ito, Yoshihiro Kawaoka, Hiroshi Kida, Kazumasa Ogasawara
    PLOS ONE 8 12 e82740  2013年12月 [査読有り][通常論文]
     
    H5N1 highly pathogenic avian influenza virus (HPAIV) infection has been reported in poultry and humans with expanding clade designations. Therefore, a vaccine that induces immunity against a broad spectrum of H5N1 viruses is preferable for pandemic preparedness. We established a second H5N1 vaccine candidate, A/duck/Hokkaido/Vac-3/2007 (Vac-3), in our virus library and examined the efficacy of inactivated whole particles of this strain against two clades of H5N1 HPAIV strains that caused severe morbidity in cynomolgus macaques. Virus propagation in vaccinated macaques infected with either of the H5N1 HPAIV strains was prevented compared with that in unvaccinated macaques. This vaccine also prevented propagation of a pandemic (H1N1) 2009 virus in macaques. In the vaccinated macaques, neutralization activity, which was mainly shown by anti-hemagglutinin antibody, against H5N1 HPAIVs in plasma was detected, but that against H1N1 virus was not detected. However, neuraminidase inhibition activity in plasma and T-lymphocyte responses in lymph nodes against H1N1 virus were detected. Therefore, cross-clade and heterosubtypic protective immunity in macaques consisted of humoral and cellular immunity induced by vaccination with Vac-3.
  • Naoki Yamamoto, Yoshihiro Sakoda, Masatoshi Okamatsu, Hiroshi Kida
    VIRUS RESEARCH 178 2 404 - 410 2013年12月 [査読有り][通常論文]
     
    Influenza virus A/Hong Kong/483/97 (H5N1) (HK483-K) has the PB2 with lysine at position 627 (PB2-627K) and is highly pathogenic in chickens and mice. On the other hand, the pathogenicity of mutant virus (HK483-E), which was generated by substituting lysine with glutamic acid at the position of the PB2, is lower than that of HK483-K in mice, but is highly pathogenic in chickens. The PB2 is one of the components of heterotrimeric polymerase complex, which plays roles in the transcription and replication of virus genes. Cell-free polymerase assay revealed that intrinsic transcription activity of the polymerase complex with PB2-627K is higher than that of glutamic acid (PB2-627E). In chicken cells, transcription efficiency of the polymerase complex with PB2-627E was not lower than those with PB2-627K, indicating that transcription of virus genes is modulated by some host factors in chicken cells, resulting in high growth. Polymerase complex with PB2-627K efficiently transcribes and replicates virus polymerase genes in mouse cells, leading to high growth of HK483-K compared with that of HK483-E. The results of our experiments clearly suggest that efficient transcription and replication of virus genes by polymerase complex result in the higher pathogenicity in mice. (C) 2013 Elsevier B.V. All rights reserved.
  • Junki Maruyama, Masatoshi Okamatsu, Kosuke Soda, Yoshihiro Sakoda, Hiroshi Kida
    ARCHIVES OF VIROLOGY 158 12 2473 - 2478 2013年12月 [査読有り][通常論文]
     
    Highly pathogenic avian influenza viruses have poly-basic amino acid sequences at the cleavage site in their hemagglutinin (HA). Although this poly-basic region is a prerequisite factor for pathogenicity in chickens, not much is known about additional factors responsible for the acquisition of pathogenicity of the duck influenza virus in chickens. Here, we introduced multiple basic amino acid residues into the HA cleavage site of the A/duck/Hokkaido/Vac-2/2004 (H7N7) strain of avian influenza virus, which has low pathogenicity in chickens; the resultant Vac2sub-P0 strain was not intravenously pathogenic in chickens. In contrast, the Vac2sub-P3 strain, which was recovered from three consecutive passages of Vac2sub-P0 in chicks, was intravenously pathogenic in chickens. Six amino acid substitutions were identified by comparison of the Vac2sub-P3 and Vac2sub-P0 genomic sequences: Lys123Glu in PB2, Asn16Asp in PB1, Glu227Gly and Ile388Thr in HA, Gly228Arg in M1, and Leu46Pro in M2. The results of intravenous inoculations of chickens with recombinant virus indicated that all six amino acid substitutions were required to varying degrees for Vac2sub-P3 pathogenicity, with Glu227Gly and Ile388Thr in HA being particularly essential. These results reveal the roles of additional viral factors in the acquisition of pathogenicity in addition to the previously characterized role of the poly-basic amino acid sequences at the HA cleavage site.
  • Akira Sakurai, Katsuyoshi Takayama, Namiko Nomura, Tsubasa Munakata, Naoki Yamamoto, Tsuruki Tamura, Jitsuho Yamada, Masako Hashimoto, Kazuhiko Kuwahara, Yoshihiro Sakoda, Yoshihiko Suda, Yukuharu Kobayashi, Nobuo Sakaguchi, Hiroshi Kida, Michinori Kohara, Futoshi Shibasaki
    PLoS ONE 8 11 e76753  2013年11月06日 [査読有り][通常論文]
     
    Immunochromatography (IC) is an antigen-detection assay that plays an important role in the rapid diagnosis of influenza virus because the protocol is short time and easy to use. Despite the usability of IC, the sensitivity is approximately 103 pfu per reaction. In addition, antigen-antibody interaction-based method cannot be used for the detection of influenza viruses with major antigenic change. In this study, we established the use of fluorescent immunochromatography (FLIC) to detect a broad spectrum of H5 subtype influenza A viruses. This method has improved sensitivity 10-100 fold higher than traditional IC because of the use of fluorescent conjugated beads. Our Type-E FLIC kit detected all of the H5 subtype influenza viruses that were examined, as well as recombinant hemagglutinin (HA) proteins (rHAs) belonging to the Eurasian H5 subtype viruses and the Type-N diagnosed North American H5 subtype influenza A viruses. Thus, this kit has the improved potential to detect H5 subtype influenza viruses of different clades with both Type-E and Type-N FLIC kits. Compared with PCR-based diagnosis, FLIC has a strong advantage in usability, because the sample preparation required for FLIC is only mix-and-drop without any additional steps such as RNA extraction. Our results can provide new strategies against the spread and transmission of HPAI H5N1 viruses in birds and mammals including humans. Copyright: © 2013 Sakurai et al.
  • Masatoshi Okamatsu, Tatsuya Nishi, Naoki Nomura, Naoki Yamamoto, Yoshihiro Sakoda, Kenji Sakurai, Huy Duc Chu, Long Pham Thanh, Long Van Nguyen, Nam Van Hoang, Tien Ngoc Tien, Reiko Yoshida, Ayato Takada, Hiroshi Kida
    VIRUS GENES 47 2 317 - 329 2013年10月 [査読有り][通常論文]
     
    To estimate the prevalence of avian influenza virus infection in Vietnam, surveillance was conducted in domestic and wild birds from households, live-bird markets, slaughtering sites, and bird sanctuaries in Vietnam between October 2010 and October 2012. Of the 4,550 samples collected, 226 influenza A virus isolates were obtained from domestic ducks, muscovy ducks, and chickens. Of these, 25 and 22 H5N1 highly pathogenic avian influenza viruses (HPAIVs) were isolated from apparently healthy domestic ducks in live-bird markets and slaughtering sites in northern and southern Vietnam, respectively. The HA genes of H5 viruses isolated from birds in northern Vietnam phylogenetically belonged to the genetic clade 2.3.2.1 and those in southern Vietnam belonged to the genetic clade 1.1. In addition, 39 H3, 12 H4, 1 H5, 93 H6, 2 H7, 18 H9, 3 H10, and 11 H11 viruses were isolated. Phylogenetic and antigenic analyses of the H6 and H9 viruses revealed that they were closely related to the isolates obtained from domestic poultry in China. Phylogenetic analyses of internal gene segments of these isolates revealed that these viruses were circulating in both domestic and wild birds in Asia and reassortment events had occurred frequently. Therefore, it will be important to continue the surveillance and strict controls over the movement and trade of poultry and poultry products in order to eradicate H5N1 HPAIV from Asia.
  • Van Loi Pham, Misako Nakayama, Yasushi Itoh, Hirohito Ishigaki, Mitsutaka Kitano, Masahiko Arikata, Hideaki Ishida, Naoko Kitagawa, Shintaro Shichinohe, Masatoshi Okamatsu, Yoshihiro Sakoda, Hideaki Tsuchiya, Shinichiro Nakamura, Hiroshi Kida, Kazumasa Ogasawara
    PLOS ONE 8 9 e75910  2013年09月 [査読有り][通常論文]
     
    Pandemic (H1N1) 2009 influenza virus spread throughout the world since most people did not have immunity against the virus. In the post pandemic phase when many humans might possess immunity against the pandemic virus, one of the concerns is infection in immunocompromised people. Therefore, we used an immunosuppressed macaque model to examine pathogenicity of the pandemic (H1N1) 2009 virus under an immunocompromised condition. The virus in nasal samples of immunosuppressed macaques infected with the pandemic (H1N1) 2009 virus was detected longer after infection than was the virus in nasal samples of immunocompetent macaques. As expected, not only virus amounts but also virus propagation sites in the immunosuppressed macaques were larger than those in lungs of the immunocompetent macaques when they were infected with the pandemic virus. Immunosuppressed macaques possessed low levels of immune cells producing cytokines and chemokines, but levels of inflammatory cytokines/chemokine interleukin (IL)-6, IL-18, and monocyte chemotactic protein (MCP)-1 in lungs of the immunosuppressed macaques were higher than those in lungs of the immunocompetent macaques, though the differences were not statistically significant. Therefore, under an immunosuppressive condition, the pandemic influenza (H1N1) 2009 virus might cause more severe morbidity with high cytokine/chemokine production by the host innate immune system than that seen in macaques under the immunocompetent condition.
  • Shichinohe S, Okamatsu M, Sakoda Y, Kida H
    Virology 444 1-2 404 - 408 2013年09月 [査読有り][通常論文]
     
    Avian influenza viruses possess hemagglutinin (HA) which preferentially bind to the sialic acid alpha 2,3-galactose sialyloligosaccharides (SA alpha 2,3Gal) receptor. In contrast, human influenza viruses bind to sialic acid alpha 2,6-galactose sialyloligosaccharides (SA alpha 2,6Gal). The A/Hong Kong/68 (H3N2) virus preferentially binds to SA alpha 2,6Gal, although its HA gene was derived from an avian influenza virus strain. To elucidate the mechanisms behind acquisition of binding specificity for the human-type receptor, the avian influenza virus, A/duck/Hokkaido/5/77 (H3N2), which carries the HA with SA alpha 2,3Gal receptor specificity, was consecutively passaged in pigs. Viruses that preferentially bind to the SA alpha 2,6Gal receptor were predominantly recovered from the nasal swabs of pigs after three passages. The present results indicate that avian influenza Viruses can acquire the potential to infect humans after multiple infections in a pig population. Intensive surveillance of swine influenza is, thus, important for the preparedness for the future pandemics. (C) 2013 Elsevier Inc. All rights reserved.
  • Tokiko Watanabe, Maki Kiso, Satoshi Fukuyama, Noriko Nakajima, Masaki Imai, Shinya Yamada, Shin Murakami, Seiya Yamayoshi, Kiyoko Iwatsuki-Horimoto, Yoshihiro Sakoda, Emi Takashita, Ryan McBride, Takeshi Noda, Masato Hatta, Hirotaka Imai, Dongming Zhao, Noriko Kishida, Masayuki Shirakura, Robert P. de Vries, Shintaro Shichinohe, Masatoshi Okamatsu, Tomokazu Tamura, Yuriko Tomita, Naomi Fujimoto, Kazue Goto, Hiroaki Katsura, Eiryo Kawakami, Izumi Ishikawa, Shinji Watanabe, Mutsumi Ito, Yuko Sakai-Tagawa, Yukihiko Sugita, Ryuta Uraki, Reina Yamaji, Amie J. Eisfeld, Gongxun Zhong, Shufang Fan, Jihui Ping, Eileen A. Maher, Anthony Hanson, Yuko Uchida, Takehiko Saito, Makoto Ozawa, Gabriele Neumann, Hiroshi Kida, Takato Odagiri, James C. Paulson, Hideki Hasegawa, Masato Tashiro, Yoshihiro Kawaoka
    NATURE 501 7468 551 - + 2013年09月 [査読有り][通常論文]
     
    Avian influenza A viruses rarely infect humans; however, when human infection and subsequent human-to-human transmission occurs, worldwide outbreaks (pandemics) can result. The recent sporadic infections of humans in China with a previously unrecognized avian influenza A virus of the H7N9 subtype (A(H7N9)) have caused concern owing to the appreciable case fatality rate associated with these infections (more than 25%), potential instances of human-to-human transmission(1), and the lack of pre-existing immunity among humans to viruses of this subtype. Here we characterize two early human A(H7N9) isolates, A/Anhui/1/2013 (H7N9) and A/Shanghai/1/2013 (H7N9); hereafter referred to as Anhui/1 and Shanghai/1, respectively. In mice, Anhui/1 and Shanghai/1 were more pathogenic than a control avian H7N9 virus (A/duck/Gunma/466/2011 (H7N9); Dk/GM466) and a representative pandemic 2009 H1N1 virus (A/California/4/2009 (H1N1pdm09); CA04). Anhui/1, Shanghai/1 and Dk/GM466 replicated well in the nasal turbinates of ferrets. In nonhuman primates, Anhui/1 and Dk/GM466 replicated efficiently in the upper and lower respiratory tracts, whereas the replicative ability of conventional human influenza viruses is typically restricted to the upper respiratory tract of infected primates. By contrast, Anhui/1 did not replicate well in miniature pigs after intranasal inoculation. Critically, Anhui/1 transmitted through respiratory droplets in one of three pairs of ferrets. Glycan arrays showed that Anhui/1, Shanghai/1 and A/Hangzhou/1/2013 (H7N9) (a third human A(H7N9) virus tested in this assay) bind to human virus-type receptors, a property that may be critical for virus transmissibility in ferrets. Anhui/1 was found to be less sensitive in mice to neuraminidase inhibitors than a pandemic H1N1 2009 virus, although both viruses were equally susceptible to an experimental antiviral polymerase inhibitor. The robust replicative ability in mice, ferrets and nonhuman primates and the limited transmissibility in ferrets of Anhui/1 suggest that A(H7N9) viruses have pandemic potential.
  • Saya Kuribayashi, Yoshihiro Sakoda, Takeshi Kawasaki, Tomohisa Tanaka, Naoki Yamamoto, Masatoshi Okamatsu, Norikazu Isoda, Yoshimi Tsuda, Yuji Sunden, Takashi Umemura, Noriko Nakajima, Hideki Hasegawa, Hiroshi Kida
    PLOS ONE 8 7 e68375  2013年07月 [査読有り][通常論文]
     
    Highly pathogenic avian influenza viruses (HPAIVs) cause lethal infection in chickens. Severe cases of HPAIV infections have been also reported in mammals, including humans. In both mammals and birds, the relationship between host cytokine response to the infection with HPAIVs and lethal outcome has not been well understood. In the present study, the highly pathogenic avian influenza viruses A/turkey/Italy/4580/1999 (H7N1) (Ty/Italy) and A/chicken/Netherlands/2586/2003 (H7N7) (Ck/NL) and the low pathogenic avian influenza virus (LPAIV) A/chicken/Ibaraki/1/2005 (H5N2) (Ck/Ibaraki) were intranasally inoculated into chickens. Ty/Italy replicated more extensively than Ck/NL in systemic tissues of the chickens, especially in the brain, and induced excessive mRNA expression of inflammatory and antiviral cytokines (IFN-gamma, IL-1 beta, IL-6, and IFN-alpha) in proportion to its proliferation. Using in situ hybridization, IL-6 mRNA was detected mainly in microglial nodules in the brain of the chickens infected with Ty/Italy. Capillary leakage assessed by Evans blue staining was observed in multiple organs, especially in the brains of the chickens infected with Ty/Italy, and was not observed in those infected with Ck/NL. In contrast, LPAIV caused only local infection in the chickens, with neither apparent cytokine expression nor capillary leakage in any tissue of the chickens. The present results indicate that an excessive cytokine response is induced by rapid and extensive proliferation of HPAIV and causes fatal multiple organ failure in chickens.
  • Ahmad M. Haredy, Nobuyuki Takenaka, Hiroshi Yamada, Yoshihiro Sakoda, Masatoshi Okamatsu, Naoki Yamamoto, Takeshi Omasa, Hisao Ohtake, Yasuko Mori, Hiroshi Kida, Koichi Yamanishi, Shigefumi Okamoto
    Clinical and Vaccine Immunology 20 7 998 - 1007 2013年07月 [査読有り][通常論文]
     
    It is currently impossible to predict the next pandemic influenza virus strain. We have thus established a library of influenza viruses of all hemagglutinin and neuraminidase subtypes and their genes. In this article, we examine the applicability of a rapid production model for the preparation of vaccines against emerging pandemic influenza viruses. This procedure utilizes the influenza virus library, cell culture-based vaccine production, and intranasal administration to induce a cross-protective immune response. First, an influenza virus reassortant from the library, A/duck/Hokkaido/Vac-3/2007 (H5N1), was passaged 22 times (P22) in Madin-Darby canine kidney (MDCK) cells. The P22 virus had a titer of > 2 × 108PFU/ml, which was 40 times that of the original strain, with 4 point mutations, which altered amino acids in the deduced protein sequences encoded by the PB2 and PA genes. We then produced a formalin-inactivated whole-virion vaccine from the MDCK cell-cultured A/duck/Hokkaido/Vac-3/2007 (H5N1) P22 virus. Intranasal immunization of mice with this vaccine protected them against challenges with lethal influenza viruses of homologous and heterologous subtypes. We further demonstrated that intranasal immunization with the vaccine induced cross-reactive neutralizing antibody responses against the homotypic H5N1 influenza virus and its antigenic variants and cross-reactive cell-mediated immune responses to the homologous virus, its variants within a subtype, and even an influenza virus of a different subtype. These results indicate that a rapid model for emergency vaccine production may be effective for producing the next generation of pandemic influenza virus vaccines. Copyright © 2013, American Society for Microbiology. All Rights Reserved.
  • Naoki Yamamoto, Kosuke Soda, Yoshihiro Sakoda, Masatoshi Okamatsu, Hiroshi Kida
    VIRUS RESEARCH 173 2 294 - 298 2013年05月 [査読有り][通常論文]
     
    Influenza virus rgVac1 sub-P0 (H5N1) (rgVac1-P0), in which a pair of dibasic,amino acid residues was introduced at the cleavage site of the HA of a reassortant of H5N2 and H7N1 viruses of duck origin, was low pathogenic in chickens. Vac1 sub-P3 (H5N1) (Vac1-P3) was selected as a highly pathogenic avian influenza virus by 3 consecutive passages in chickens from low pathogenic strain rgVac1-P0. Comparison of amino acid sequences of the virus proteins and experimental infection of chickens with a series of recombinant viruses demonstrated that in addition to the HA, each of the PA, NP, M1, and M2 of Vac1-P3 are responsible for the acquisition of pathogenicity in chickens. These 4 proteins of Vac1-P3 synergistically contributed to efficient virus replication in chickens. (C) 2013 Elsevier B.V. All rights reserved.
  • Shintaro Shichinohe, Masatoshi Okamatsu, Naoki Yamamoto, Yu Noda, Yuka Nomoto, Takashi Honda, Noriyasu Takikawa, Yoshihiro Sakoda, Hiroshi Kida
    VETERINARY MICROBIOLOGY 164 1-2 39 - 45 2013年05月 [査読有り][通常論文]
     
    Antigenic variants of H5N1 highly pathogenic avian influenza virus (HPAIV) have selected and are prevailing in poultry populations in Asia. In the present study, the potency of inactivated influenza vaccine prepared from a non-pathogenic H5N1 avian influenza virus, A/duck/Hokkaido/Vac-3/2007 (H5N1), was assessed by challenging with H5N1 HPAIV variants, A/muscovy duck/Vietnam/OIE-559/2011 (H5N1), A/whooper swan/Hokkaido/4/2011 (H5N1), and A/peregrine falcon/Hong Kong/810/2009 (H5N1) belonging to clades 1, 23.2.1, and 2.3.4, respectively. All chickens immunized with the Vac-3 vaccine survived without showing any clinical signs after intranasal challenge either with A/whooper swan/Hokkaido/4/2011 (H5N1) or A/muscovy duck/Vietnam/OIE-559/2011 (H5N1). After challenge with A/peregrine falcon/Hong Kong/810/2009 (H5N1), 10 out of 12 vaccinated chickens survived and the other 2 died on 4 or 7 post-challenge days. The Vac-3 vaccine of 2.4-fold antigen concentration conferred complete protective immunity in chickens against challenge with A/peregrine falcon/Hong Kong/810/2009 (H5N1). (C) 2013 Elsevier B.V. All rights reserved.
  • Yurie Motohashi, Manabu Igarashi, Masatoshi Okamatsu, Takeshi Noshi, Yoshihiro Sakoda, Naoki Yamamoto, Kimihito Ito, Ryu Yoshida, Hiroshi Kida
    VIROLOGY JOURNAL 10 118  2013年04月 [査読有り][通常論文]
     
    Background: The hemagglutinin (HA) of influenza viruses is a possible target for antiviral drugs because of its key roles in the initiation of infection. Although it was found that a natural compound, Stachyflin, inhibited the growth of H1 and H2 but not H3 influenza viruses in MDCK cells, inhibitory activity of the compound has not been assessed against H4-H16 influenza viruses and the precise mechanism of inhibition has not been clarified. Methods: Inhibitory activity of Stachyflin against H4-H16 influenza viruses, as well as H1-H3 viruses was examined in MDCK cells. To identify factors responsible for the susceptibility of the viruses to this compound, Stachyflin-resistant viruses were selected in MDCK cells and used for computer docking simulation. Results: It was found that in addition to antiviral activity of Stachyflin against influenza viruses of H1 and H2 subtypes, it inhibited replication of viruses of H5 and H6 subtypes, as well as A(H1N1)pdm09 virus in MDCK cells. Stachyflin also inhibited the virus growth in the lungs of mice infected with A/WSN/1933 (H1N1) and A/chicken/Ibaraki/1/2005 (H5N2). Substitution of amino acid residues was found on the HA2 subunit of Stachyflin-resistant viruses. Docking simulation indicated that D37, K51, T107, and K121 are responsible for construction of the cavity for the binding of the compound. In addition, 3-dimensional structure of the cavity of the HA of Stachyflin-susceptible virus strains was different from that of insusceptible virus strains. Conclusion: Antiviral activity of Stachyflin was found against A(H1N1) pdm09, H5, and H6 viruses, and identified a potential binding pocket for Stachyflin on the HA. The present results should provide us with useful information for the development of HA inhibitors with more effective and broader spectrum.
  • Feng F, Sakoda Y, Ohyanagi T, Nagahori N, Shibuya H, Okamastu M, Miura N, Kida H, Nishimura SI
    Antiviral therapy 2013年02月 [査読有り][通常論文]
  • Masahiro Kajihara, Yoshihiro Sakoda, Kosuke Soda, Kenji Minari, Masatoshi Okamatsu, Ayato Takada, Hiroshi Kida
    VIROLOGY JOURNAL 10 45  2013年02月 [査読有り][通常論文]
     
    Background: Wild ducks are the natural hosts of influenza A viruses. Duck influenza, therefore, has been believed inapparent infection with influenza A viruses, including highly pathogenic avian influenza viruses (HPAIVs) in chickens. In fact, ducks experimentally infected with an HPAIV strain, A/Hong Kong/483/1997 (H5N1) (HK483), did not show any clinical signs. Another HPAIV strain, A/whooper swan/Mongolia/3/2005 (H5N1) (MON3) isolated from a dead swan, however, caused neurological dysfunction and death in ducks. Method: To understand the mechanism whereby MON3 shows high pathogenicity in ducks, HK483, MON3, and twenty-four reassortants generated between these two H5N1 viruses were compared for their pathogenicity in domestic ducks. Results: None of the ducks infected with MON3-based single-gene reassortants bearing the PB2, NP, or NS gene segment of HK483 died, and HK483-based single-gene reassortants bearing PB2, NP, or NS genes of MON3 were not pathogenic in ducks, suggesting that multiple gene segments contribute to the pathogenicity of MON3 in ducks. All the ducks infected with the reassortant bearing PB2, PA, HA, NP, and NS gene segments of MON3 died within five days post-inoculation, as did those infected with MON3. Each of the viruses was assessed for replication in ducks three days post-inoculation. MON3 and multi-gene reassortants pathogenic in ducks were recovered from all of the tissues examined and replicated with high titers in the brains and lungs. Conclusion: The present results indicate that multigenic factors are responsible for efficient replication of MON3 in ducks. In particular, virus growth in the brain might correlate with neurological dysfunction and the disease severity.
  • Masatoshi Okamatsu, Yoshihiro Sakoda, Takahiro Hiono, Naoki Yamamoto, Hiroshi Kida
    VIROLOGY JOURNAL 10 47  2013年02月 [査読有り][通常論文]
     
    Background: The pandemic 2009 (H1N1) influenza virus has spread throughout the world and is now causing seasonal influenza. To prepare for the emergence of pandemic influenza, we have established a library of virus strains isolated from birds, pigs, and humans in global surveillance studies. Methods: Inactivated whole virus particle (WV) and ether-split (ES) vaccines were prepared from an influenza virus strain, A/swine/Hokkaido/2/1981 (H1N1), from the library and from A/Narita/1/2009 (H1N1) pandemic strain. Each of the vaccines was injected subcutaneously into mice and their potencies were evaluated by challenge with A/Narita/1/2009 (H1N1) virus strain in mice. Results: A/swine/Hokkaido/2/81 (H1N1), which was isolated from the lung of a diseased piglet, was selected on the basis of their antigenicity and growth capacity in embryonated chicken eggs. Two injections of the WV vaccine induced an immune response in mice, decreasing the impact of disease caused by the challenge with A/Narita/1/2009 (H1N1), as did the vaccine prepared from the homologous strain. Conclusion: The WV vaccine prepared from an influenza virus in the library is useful as an emergency vaccine in the early phase of pandemic influenza.
  • Masatoshi Okamatsu, Fei Feng, Tatsuya Ohyanagi, Noriko Nagahori, Kazuhiko Someya, Yoshihiro Sakoda, Nobuaki Miura, Shin-Ichiro Nishimura, Hiroshi Kida
    JOURNAL OF VIROLOGICAL METHODS 187 2 390 - 394 2013年02月 [査読有り][通常論文]
     
    Attachment of influenza virus to susceptible cells is mediated by viral protein hemagglutinin (HA), which recognizes cell surface glycoconjugates that terminate in alpha-sialosides. To develop anti-influenza drugs based on inhibition of HA-mediated infection, novel fluorescent nanoparticles displaying multiple biantennary N-glycan chains with alpha-sialosides (A2-PC-QDs) that have high affinity for the HA were designed and constructed. The A2-PC-QDs enabled an easy and efficient fluorescence polarization (FP) assay for detection of interaction with the HA and competitive inhibition even by small molecule compounds against A2-PC-QDs-HA binding. The quantum dot (QD)-based FP assay established in the present study is a useful tool for high-throughput screening and to accelerate the development of novel and more effective blockers of the viral attachment of influenza virus. (C) 2012 Elsevier B.V. All rights reserved.
  • Fei Feng, Yoshihiro Sakoda, Tatsuya Ohyanagi, Noriko Nagahori, Hitomi Shibuya, Masatoshi Okamastu, Nobuaki Miura, Hiroshi Kida, Shin-Ichiro Nishimura
    Antiviral Chemistry and Chemotherapy 23 2 59 - 65 2013年 [査読有り][通常論文]
     
    Background: The purpose of this study was to develop a new class of influenza A virus haemagglutinin (HA) blockers by tethering thiosialoside molecules to metal nanoparticles and producing glycoclusters that enhance the affinity of HA binding by N-acetylneuraminic acid. Methods: Oxygen of the glycoside bond of sialoside was replaced with sulfur to prevent hydrolytic digestion of the N-acetylneuraminic acid residue by viral neuraminidase. Two novel thiosialosides, α-2-S-[p-(N-levulinyl) aminophenyl]-5-N-acetylneuraminic acid (Neu5Ac-S-Lev) and α-2-S-[m-(N-levulinyl)aminobenzyl]-5-Nacetylneuraminic acid (Neu5Ac-S-CH 2-Lev), were tethered onto the surface of metal nanoparticles via an aminooxy functionalized thiol linker in a glycoblotting reaction. Gold (Au) and silver (Ag) nanoparticles were coated simultaneously with 11-mercaptoundecyl phosphorylcholine to reduce non-specific adsorption of proteins. Phosphorylcholine self-assembled monolayercoated metals displaying clustered Neu5Ac (Neu5Ac-PCSAM-Au and Neu5Ac-PCSAM-Ag) were subjected to haemagglutination inhibition (HI) assays using the influenza A virus strain A/PR/8/1934 (H1N1). Results: Glyconanoparticles with thiosialosides had potent HI activities. In particular, Neu5Ac-PCSAM-Au with a diameter of 20 nm corresponding to 9.8 μM monosaccharide Neu5Ac was the most potent HA inhibitor. The versatility of this strategy was demonstrated by similar submicromolar HI activities of Neu5Ac-PCSAM--Ag with diameters of 50 nm and 150 nm. Conclusions: Glycosylated metal nanoparticles were designed and synthesized as potent influenza A virus HA blockers. This study may contribute to the acceleration of the discovery of a new class of nanoparticle antiinfluenza drugs. © 2013 International Medical Press.
  • Norikazu Isoda, Yoshimi Tsuda, Shingo Asakura, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida
    ARCHIVES OF VIROLOGY 157 12 2257 - 2264 2012年12月 [査読有り][通常論文]
     
    Avian influenza viruses A/duck/Mongolia/47/2001 (H7N1) (47/01) and A/duck/Mongolia/867/2002 (H7N1) (867/02) were defined as low-pathogenic avian influenza viruses (LPAIVs) using an intravenous pathogenicity test in chickens. On the other hand, the intracerebral pathogenicity indices of 47/01 and 867/02 were 1.30 and 0.00, respectively. A series of reassortant viruses were generated between 47/01 and 867/02, and their intracerebral pathogenicity was compared in one-day-old chicks to identify the protein(s) responsible for the intracerebral pathogenicity of 47/01. The results indicate that the amino acids at positions 50 and 98 of the nucleoprotein are related to the pathogenicity of 47/01 in chicks by intracerebral inoculation. A significant association was found between mortality of the chicks inoculated intracerebrally with 47/01 and virus replication in the lungs and/or brain. These results indicate that the NP of avian influenza viruses may be responsible for intracerebral pathogenicity in the host.
  • Tomokazu Tamura, Yoshihiro Sakoda, Fumi Yoshino, Takushi Nomura, Naoki Yamamoto, Yuka Sato, Masatoshi Okamatsu, Nicolas Ruggli, Hiroshi Kida
    JOURNAL OF VIROLOGY 86 16 8602 - 8613 2012年08月 [査読有り][通常論文]
     
    Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), a highly contagious disease of pigs. There are numerous CSFV strains that differ in virulence, resulting in clinical disease with different degrees of severity. Low-virulent and moderately virulent isolates cause a mild and often chronic disease, while highly virulent isolates cause an acute and mostly lethal hemorrhagic fever. The live attenuated vaccine strain GPE(-) was produced by multiple passages of the virulent ALD strain in cells of swine, bovine, and guinea pig origin. With the aim of identifying the determinants responsible for the attenuation, the GPE- vaccine virus was readapted to pigs by serial passages of infected tonsil homogenates until prolonged viremia and typical signs of CSF were observed. The GPE(-)/P-11 virus isolated from the tonsils after the 11th passage in vivo had acquired 3 amino acid substitutions in E2 (T830A) and NS4B (V2475A and A2563V) compared with the virus before passages. Experimental infection of pigs with the mutants reconstructed by reverse genetics confirmed that these amino acid substitutions were responsible for the acquisition of pathogenicity. Studies in vitro indicated that the substitution in E2 influenced virus spreading and that the changes in NS4B enhanced the viral RNA replication. In conclusion, the present study identified residues in E2 and NS4B of CSFV that can act synergistically to influence virus replication efficiency in vitro and pathogenicity in pigs.
  • Yoshihiro Sakoda, Hiroaki Wakamoto, Tehpin Tamura, Takushi Nomura, Michiko Naito, Hiroshi Aoki, Hiroshi Morita, Hiroshi Kida, Akio Fukusho
    JAPANESE JOURNAL OF VETERINARY RESEARCH 60 2-3 85 - 94 2012年08月 [査読有り][通常論文]
     
    An indirect enzyme-linked immunosorbent assay (ELISA) was developed for a screening test to detect antibodies against classical swine fever virus (CSFV). Viral glycoproteins, which were purified from swine kidney cells infected with CSFV ALD/A76 strain by the immunoaffinity purification using monoclonal antibody against E2 protein, were adsorbed on a microtiter plate as the antigen for the antibody detection. Each antibody titer of serum sample was expressed as a sample per positive value calculated with optical absorbance of each sample and that of a positive control. The advantage of this ELISA is its higher sensitivity: most sera containing more than 4 neutralization titers were determined to be positive. This ELISA is unable to discriminate between antibodies against CSFV and those against other ruminant pestiviruses, therefore positive sera in this ELISA should be evaluated by a cross-neutralization test using CSFV, bovine viral diarrhea virus, and border disease virus. Taken together, the indirect ELISA developed in this study is useful screening tool to detect antibodies against CSFV for the large-scale monitoring of classical swine fever.
  • Yoshihiro Sakoda, Michiko Naito, Mutsumi Ito, Yuki Ito, Norikazu Isoda, Tomohisa Tanaka, Takashi Umemura, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 74 7 955 - 958 2012年07月 [査読有り][通常論文]
     
    Leptospira interrogans serovar Manilae strain UP-MMC was inoculated into miniature pigs to assess its pathogenicity. Leptospires were recovered from the whole blood, kidneys, and livers in the acute phase without showing any clinical signs. Under immunosuppressive conditions by dexamethasone, leptospires were recovered from the kidneys and their genes were detected from the urine in the chronic phase. These results indicate that leptospires persisted in the kidneys until the chronic phase, and excretion of leptospires in the urine was enhanced under immunosuppressive conditions, resulting in horizontal transmission among pigs on farms.
  • Yoshihiro Sakoda, Masatoshi Okamatsu, Norikazu Isoda, Naoki Yamamoto, Koichi Ozaki, Yasuto Umeda, Shigeyuki Aoyama, Hiroshi Kida
    MICROBIOLOGY AND IMMUNOLOGY 56 7 490 - 495 2012年07月 [査読有り][通常論文]
     
    Affinity chromatography using sulfated, spherical cellulose beads (Cellufine Sulfate) was assessed for purification of influenza A and influenza B viruses. Recovery rates of viruses eluted from the beads were high for all tested virus strains. This method was also useful for removing chicken egg-derived impurities from allantoic fluids containing influenza viruses; the hemagglutination activity per amount of protein in the eluted sample was significantly higher than that in the applied sample. These results suggest that use of Cellufine Sulfate is a practical method for primary purification of influenza viruses in the process of influenza vaccine production.
  • Masahiko Arikata, Yasushi Itoh, Masatoshi Okamatsu, Toshinaga Maeda, Takashi Shiina, Keiko Tanaka, Shingo Suzuki, Misako Nakayama, Yoshihiro Sakoda, Hirohito Ishigaki, Ayato Takada, Hideaki Ishida, Kosuke Soda, Van Loi Pham, Hideaki Tsuchiya, Shinichiro Nakamura, Ryuzo Torii, Takeshi Shimizu, Hidetoshi Inoko, Iwao Ohkubo, Hiroshi Kida, Kazumasa Ogasawara
    PLOS ONE 7 5 e37220  2012年05月 [査読有り][通常論文]
     
    We made an H1N1 vaccine candidate from a virus library consisting of 144 (= 16 HAx9 NA) non-pathogenic influenza A viruses and examined its protective effects against a pandemic (2009) H1N1 strain using immunologically naive cynomolgus macaques to exclude preexisting immunity and to employ a preclinical study since preexisting immunity in humans previously vaccinated or infected with influenza virus might make comparison of vaccine efficacy difficult. Furthermore, macaques carrying a major histocompatibility complex class I molecule, Mafa-A1*052:02, were used to analyze peptide-specific CD8(+) T cell responses. Sera of macaques immunized with an inactivated whole particle formulation without addition of an adjuvant showed higher neutralization titers against the vaccine strain A/Hokkaido/2/1981 (H1N1) than did sera of macaques immunized with a split formulation. Neutralization activities against the pandemic strain A/Narita/1/2009 (H1N1) in sera of macaques immunized twice with the split vaccine reached levels similar to those in sera of macaques immunized once with the whole particle vaccine. After inoculation with the pandemic virus, the virus was detected in nasal samples of unvaccinated macaques for 6 days after infection and for 2.67 days and 5.33 days on average in macaques vaccinated with the whole particle vaccine and the split vaccine, respectively. After the challenge infection, recall neutralizing antibody responses against the pandemic virus and CD8(+) T cell responses specific for nucleoprotein peptide NP262-270 bound to Mafa-A1*052:02 in macaques vaccinated with the whole particle vaccine were observed more promptly or more vigorously than those in macaques vaccinated with the split vaccine. These findings demonstrated that the vaccine derived from our virus library was effective for pandemic virus infection in macaques and that the whole particle vaccine conferred more effective memory and broader cross-reactive immune responses to macaques against pandemic influenza virus infection than did the split vaccine.
  • Naoki Nomura, Yoshihiro Sakoda, Kosuke Soda, Masatoshi Okamatsu, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 74 4 441 - 447 2012年04月 [査読有り][通常論文]
     
    H9N2 influenza viruses circulate in wild birds and poultry in Eurasian countries, and have been isolated from pigs and humans in China. H9N2 viruses isolated from birds, pigs and humans have been classified into three sublineages based on antigenic and genetic features. Chicken antisera to H9N2 viruses of the Korean sublineage reacted with viruses of different sublineages by the hemagglutination-inhibition test. A test vaccine prepared from a non-pathogenic A/duck/Hokkaido/49/1998 (H9N2) strain of the Korean sublineage, obtained from our influenza virus library, induced immunity in mice to reduce the impact of disease caused by the challenge with A/Hong Kong/1073/1999 (H9N2), which is of a different sublineage. The present results indicate that an inactivated whole virus vaccine prepared from a non-pathogenic influenza virus from the library could be used as an emergency vaccine during the early stage of a pandemic caused by H9N2 infection.
  • Yoshihiro Sakoda, Hiroshi Ito, Yuko Uchida, Masatoshi Okamatsu, Naoki Yamamoto, Kosuke Soda, Naoki Nomura, Saya Kuribayashi, Shintaro Shichinohe, Yuji Sunden, Takashi Umemura, Tatsufumi Usui, Hiroichi Ozaki, Tsuyoshi Yamaguchi, Toshiyuki Murase, Toshihiro Ito, Takehiko Saito, Ayato Takada, Hiroshi Kida
    JOURNAL OF GENERAL VIROLOGY 93 3 541 - 550 2012年03月 [査読有り][通常論文]
     
    H5N1 highly pathogenic avian influenza virus (HPAIV) was reintroduced and caused outbreaks in chickens in the 2010-2011 winter season in Japan, which had been free from highly pathogenic avian influenza (HPAI) since 2007 when HPAI outbreaks occurred and were controlled. On 14 October 2010 at Lake Ohnuma, Wakkanai, the northernmost part of Hokkaido, Japan, H5N1 HPAIVs were isolated from faecal samples of ducks flying from their nesting lakes in Siberia. Since then, in Japan, H5N1 HPAIVs have been isolated from 63 wild birds in 17 prefectures and caused HPAI outbreaks in 24 chicken farms in nine prefectures by the end of March in 2011. Each of these isolates was genetically closely related to the HPAIV isolates at Lake Ohnuma, and those in China, Mongolia, Russia and Korea, belonging to genetic clade 2.3.2.1. In addition, these isolates were genetically classified into three groups, suggesting that the viruses were transmitted by migratory water birds through at least three different routes from their northern territory to Japan. These isolates were antigenic variants, which is consistent with selection in poultry under the immunological pressure induced by vaccination. To prevent the perpetuation of viruses in the lakes where water birds nest in summer in Siberia, prompt eradication of HPAIVs in poultry is urgently needed in Asian countries where HPAI has not been controlled.
  • Naoki Nomura, Yoshihiro Sakoda, Mayumi Endo, Hiromi Yoshida, Naoki Yamamoto, Masatoshi Okamatsu, Kenji Sakurai, Nam Van Hoang, Long Van Nguyen, Huy Duc Chu, Tien Ngoc Tien, Hiroshi Kida
    ARCHIVES OF VIROLOGY 157 2 247 - 257 2012年02月 [査読有り][通常論文]
     
    In the surveillance of avian influenza in Vietnam, 26 H9N2, 1 H3N2, 1 H3N8, 7 H4N6, 3 H11N3, and 1 H11N9 viruses were isolated from tracheal and cloacal swab samples of 300 domestic ducks in April 2009, and 1 H9N6 virus from 300 bird samples in March 2010. Out of the 27 H9 virus isolates, the hemagglutinins of 18 strains were genetically classified as belonging to the sublineage G1, and the other nine belonged to the Korean sublineage. Phylogenetic analysis revealed that one of the 27 H9 viruses was a reassortant in which the PB2 gene belonged to the Korean sublineage and the other seven genes belonged to the G1 sublineage. Three representative H9N2 viruses were intranasally inoculated into ducks, chickens, pigs, and mice. On the basis of experimental infection studies, it was found that each of the three viruses readily infected pigs and replicated in their upper respiratory tracts, and they infected chickens with slight replication. Viruses were recovered from the lungs of mice inoculated with two of the three isolates. The present results reveal that H9 avian influenza viruses are prevailing and genetic reassortment occurs among domestic ducks in Vietnam. It is recommended that careful surveillance of swine influenza with H9 viruses should be performed to prepare for pandemic influenza.
  • Matthias Liniger, Herve R. Moulin, Yoshihiro Sakoda, Nicolas Ruggli, Artur Summerfield
    VIROLOGY JOURNAL 9 7  2012年01月 [査読有り][通常論文]
     
    Background: Influenza A viruses are well characterized to antagonize type I IFN induction in infected mammalian cells. However, limited information is available for avian cells. It was hypothesised that avian influenza viruses (AIV) with distinct virulence may interact differently with the avian innate immune system. Therefore, the type I IFN responses induced by highly virulent and low virulent H5N1 AIV and reassortants thereof were analysed in chicken cells. Results: The highly pathogenic (HP) AIV A/chicken/Yamaguchi/7/04 (H5N1) (Yama) did not induce type I IFN in infected chicken HD-11 macrophage-like cells. This contrasted with an NS1 mutant Yama virus (Yama-NS1(A144V)) and with the attenuated H5N1 AIV A/duck/Hokkaido/Vac-1/04 (Vac) carrying the haemagglutinin (HA) of the Yama virus (Vac-Yama/HA), that both induced type I IFN in these cells. The substitution of the NS segment from Yama with that from Vac in the Yama backbone resulted in induction of type I IFN secretion in HD-11 cells. However, vice versa, the Yama NS segment did not prevent type I IFN induction by the Vac-Yama/HA virus. This was different with the PB1/PB2/PA segment reassortant Yama and Vac-Yama/HA viruses. Whereas the Yama virus with the Vac PB1/PB2/PA segments induced type I IFN in HD-11 cells, the Vac-Yama/HA virus with the Yama PB1/PB2/PA segments did not. As reported for mammalian cells, the expression of H5N1 PB2 inhibited the activation of the IFN-beta promoter in chicken DF-1 fibroblast cells. Importantly, the Yama PB2 was more potent at inhibiting the IFN-beta promoter than the Vac PB2. Conclusions: The present study demonstrates that the NS1 protein and the polymerase complex of the HPAIV Yama act in concert to antagonize chicken type I IFN secretion in HD-11 cells. PB2 alone can also exert a partial inhibitory effect on type I IFN induction. In conclusion, the control of type I IFN induction by H5N1 HPAIV represents a complex phenotype that involves a particular viral gene constellation rather than a single viral protein. Collectively, these findings contribute to understand the high virulence of HPAIV H5N1 viruses observed in the chicken host.
  • Sakoda Y
    Uirusu 61 239 - 248 2 2011年12月 [査読有り][通常論文]
  • Akira Sakurai, Namiko Nomura, Reiko Nanba, Takayuki Sinkai, Tsunehito Iwaki, Taminori Obayashi, Kazuhiro Hashimoto, Michiya Hasegawa, Yoshihiro Sakoda, Akihiro Naito, Yoshihito Morizane, Mitsugu Hosaka, Kunio Tsuboi, Hiroshi Kida, Akemi Kai, Futoshi Shibasaki
    JOURNAL OF VIROLOGICAL METHODS 178 1-2 75 - 81 2011年12月 [査読有り][通常論文]
     
    The development of a rapid and sensitive system for detecting influenza viruses is a high priority for controlling future epidemics and pandemics. Quantitative real-time PCR is often used for detecting various kinds of viruses; however, it requires more than 2 h per run. Detection assays were performed with super high-speed RT-PCR (SHRT-PCR) developed according to a newly designed heating system. The new method uses a high-speed reaction (18 s/cycle; 40 cycles in less than 20 min) for typing influenza viruses. The detection limit of SHRT-PCR was 1 copy/reaction and 10(-1) plaque-forming unit/reaction for viruses in culture supernatants during 20 min. Using SHRT-PCR, 86 strains of influenza viruses isolated by the Tokyo Metropolitan Institute of Public Health were tested; the results showed 100% sensitivity and specificity for each influenza A and B virus, and swine-origin influenza virus. Twenty-seven swabs collected from the pharyngeal mucosa of outpatients were also tested, showing positive signs for influenza virus on an immunochromatographic assay; the results between SHRT-PCR and immunochromatography exhibited 100% agreement for both positive and negative results. The rapid reaction time and high sensitivity of SHRT-PCR makes this technique well suited for monitoring epidemics and pre-pandemic influenza outbreaks. (C) 2011 Published by Elsevier B.V.
  • Atsuhiko Wada, Yoshihiro Sakoda, Takayoshi Oyamada, Hiroshi Kida
    JOURNAL OF VIROLOGICAL METHODS 178 1-2 82 - 86 2011年12月 [査読有り][通常論文]
     
    H5N1, a highly pathogenic avian influenza virus (HPAIV), has become a serious epizootic threat to the poultry population in Asia. In addition, significant numbers of human cases of HPAIV infection have been reported to date. To prevent the spread of HPAIV among humans and to allow for timely medical intervention, a rapid and high sensitive method is needed to detect and subtype the causative HPAIVs. In the present study, a silver amplification technique used in photographic development was combined with immunochromatography technologies and a highly sensitive and rapid diagnostic test to detect the hemagglutinin of H5 influenza viruses was developed. The sensitivity of the test kit was increased 500 times by silver amplification. The sensitivity of the method was more than 10 times higher than those of conventional rapid influenza diagnostic tests, which detect viral nucleoproteins. The diagnostic system developed in the present study can therefore provide rapid and highly sensitive results and will be useful for diagnosis of H5 HPAIV infection in humans and animals. (C) 2011 Elsevier B.V. All rights reserved.
  • Masayuki Motoshima, Masatoshi Okamatsu, Shingo Asakura, Saya Kuribayashi, Sugar Sengee, Damdinjav Batchuluun, Mika Ito, Yukiko Maeda, Mariko Eto, Yoshihiro Sakoda, Ruuragchaa Sodnomdarjaa, Hiroshi Kida
    ARCHIVES OF VIROLOGY 156 8 1379 - 1385 2011年08月 [査読有り][通常論文]
     
    A/equine/Kanazawa/1/2007 (H3N8), A/equine/Hokkaido/I828/2008 (H3N8) and A/equine/Mongolia/1/2008 (H3N8) were isolated from infected horses. A/equine/Yokohama/aq19/2009 (H3N8) and A/equine/Yokohama/aq13/2010 (H3N8) were isolated from horses imported from Canada and Belgium examined at the Animal Quarantine Service in Yokohama, Japan. In the present study, these five isolates were genetically and antigenically analyzed. Phylogenetic analysis of hemagglutinin (HA) and neuraminidase (NA) genes showed that three isolates from horses in Japan and imported from Canada belonged to the same branch, clade 1 of the Florida sublineage, while the isolates from horses in Mongolia and imported from Belgium belonged to another branch, clade 2 of the Florida sublineage. Reactivity patterns of a panel of monoclonal antibodies to the HA of A/equine/Kanazawa/1/2007 (H3N8) with the five isolates indicate that the HAs of these viruses were antigenically similar to each other and to the reference strains A/equine/La Plata/1/1993 (H3N8) and A/equine/Avesta/1/1993 (H3N8). The present findings indicate that extensive antigenic variation has not accumulated among H3N8 influenza viruses in horses.
  • Masahiro Kajihara, Keita Matsuno, Edgar Simulundu, Mieko Muramatsu, Osamu Noyori, Rashid Manzoor, Eri Nakayama, Manabu Igarashi, Daisuke Tomabechi, Reiko Yoshida, Masatoshi Okamatsu, Yoshihiro Sakoda, Kimihito Ito, Hiroshi Kida, Ayato Takada
    JAPANESE JOURNAL OF VETERINARY RESEARCH 59 2-3 89 - 100 2011年08月 [査読有り][通常論文]
     
    In 2010, an H5N1 highly pathogenic avian influenza virus (HPAIV) was isolated from feces of apparently healthy ducks migrating southward in Hokkaido, the northernmost prefecture of Japan. The H5N1 HPAIVs were subsequently detected in domestic and wild birds at multiple sites corresponding to the flyway of the waterfowl having stopovers in the Japanese archipelago. The Hokkaido isolate was genetically nearly identical to H5N1 HPAIVs isolated from swans in the spring of 2009 and 2010 in Mongolia, but less pathogenic in experimentally infected ducks than the 2009 Mongolian isolate. These findings suggest that H5N1 HPAIVs with relatively mild pathogenicity might be selected and harbored in the waterfowl population during the 2009-2010 migration seasons. Our data provide "early warning" signals for preparedness against the unprecedented situation in which the waterfowl reservoirs serve as perpetual sources and disseminators of HPAIVs.
  • Hiromi Yoshida, Yoshihiro Sakoda, Mayumi Endo, Masayuki Motoshima, Fumi Yoshino, Naoki Yamamoto, Masatoshi Okamatsu, Takahiro Soejima, Syouhei Senba, Hidetoshi Kanda, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 73 6 753 - 758 2011年06月 [査読有り][通常論文]
     
    Migratory water birds are a natural reservoir for influenza A viruses. Viruses replicate in the intestines of ducks and are shed with the fecal materials. Virus isolation from collected fecal materials, therefore, is an integral part of the surveillance of avian influenza in water birds. In the present study, reverse transcription loop-mediated isothermal amplification (RT-LAMP) was assessed for its usefulness in detecting the RNA of influenza A viruses in fecal materials. It was found that, RT-LAMP specifically and sensitively detects the matrix gene of influenza A viruses. Influenza A viruses were isolated from the fecal materials in which viral RNA were detected by RT-LAMP in 35 min. The present findings indicate that RI-LAMP is useful as a high throughput screening method for field samples prior to virus isolation, allowing the processing of hundreds of samples per day.
  • Kosuke Soda, Ming-Chu Cheng, Hiromi Yoshida, Mayumi Endo, Shu-Hwae Lee, Masatoshi Okamatsu, Yoshihiro Sakoda, Ching-Ho Wang, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 73 6 767 - 772 2011年06月 [査読有り][通常論文]
     
    H5N2 viruses were isolated from cloacal swab samples of apparently healthy chickens in Taiwan in 2003 and 2008 during surveillance of avian influenza. Each of the viruses was eradicated by stamping out. The official diagnosis report indicated that the Intravenous Pathogenicity Indexes (IVPIs) of the isolates were 0.00 and 0.89, respectively, indicating that these were low pathogenic strains, although the hemagglutinin of the strain isolated in 2008 (Taiwan08) had multibasic amino acid residues at the cleavage site (PQRKKR/G). In the present study, these H5N2 viruses were assessed for their intravenous and intranasal pathogenicity for chickens. It was examined whether Taiwan08 acquires pathogenicity through consecutive passages in chickens. Intravenous pathogenicity of Taiwan08 depended upon the age of the chickens used for the IVPI test; all of the eight-week-old chickens intravenously inoculated with Taiwan08 showed clinical signs but survived for ten days post inoculation (IVPI=0.68), whereas all the six-week-old chickens died (IVPI=1.86). Taiwan08-P8, which were passaged in chickens for eight times, killed all the eight-week-old chickens (IVPI=2.36). The four-week-old chickens died after intranasal inoculation of Taiwan08-P8, indicating that Taiwan08 must have become highly pathogenic during circulation in chicken flocks. These results emphasize the importance of a stamping out policy for avian influenza even if the IVPI of the causal virus is low.
  • Naoki Nomura, Yoshihiro Sakoda, Kosuke Soda, Masatoshi Okamatsu, Hiroshi Kida
    INFLUENZA AND OTHER RESPIRATORY VIRUSES 5 363 - 366 2011年05月 [査読有り][通常論文]
  • Kosuke Soda, Shingo Asakura, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida
    INFLUENZA AND OTHER RESPIRATORY VIRUSES 5 272 - 276 2011年05月 [査読有り][通常論文]
  • Eiji Miyagawa, Hiroyuki Kogaki, Yoshiaki Uchida, Nobuyuki Fujii, Takashi Shirakawa, Yoshihrio Sakoda, Hiroshi Kida
    JOURNAL OF VIROLOGICAL METHODS 173 2 213 - 219 2011年05月 [査読有り][通常論文]
     
    Three anti-H5 influenza virus monoclonal antibody (mAb) clones, IFH5-26, IFH5-115 and IFH5-136, were obtained by immunising a BALB/C mouse with inactivated A/duck/Hokkaido/Vac-1/04 (H5N1). These mAbs were found to recognise specifically the haemagglutinin (HA) epitope of the influenza H5 subtypes by western blotting with recombinant HAs; however, these mAbs have no neutralising activity for A/duck/Hokkaido/84/02 (H5N3) or A/Puerto Ric/8/34 (H1N1). Each epitope of these mAbs was a conformational epitope that was formed from the regions located between 46 to 60 amino acids (aa) and 312 to 322 aa for IFH5-115, from 101 to 113 aa and 268 to 273 aa for IFH5-136 and from 61 to 80 aa and 290 to 300 aa for IFH5-26. The epitopes were located in the loop regions between the receptor region and alpha-helix structure in haemagglutinin 1 (HA1). Influenza A virus H5-specific rapid immunochromatographic test kits were tested as solid phase antibody/alkaline phosphate-conjugated mAb in the following three combinations: IFH5-26/IFH5-115, IFH5-136/IFH5-26 and IFH5-136/IFH5-115. In every combination, only influenza A H5 subtypes were detected. For effective clinical application, rapid dual discrimination immunochromatographic test kits in combination with H5 HA-specific mAb, IFA5-26 and IFA5-115 and the influenza A NP NP-specific mAb, FVA2-11, were developed. The dual discrimination immunochromatographic tests kits detected influenza A virus H5 subtypes as H5 line-positive and all influenza A subtypes as A line-positive simultaneously. The dual discrimination immunochromatographic test kits may be useful for discriminating highly pathogenic avian influenza A H5N1 viruses from seasonal influenza A virus, as well as for confirming influenza infection status in human, avian and mammalian hosts. (C) 2011 Elsevier B.V. All rights reserved.
  • Norikazu Isoda, Yoshihiro Sakoda, Masatoshi Okamatsu, Yoshimi Tsuda, Hiroshi Kida
    ARCHIVES OF VIROLOGY 156 4 557 - 563 2011年04月 [査読有り][通常論文]
     
    The avian influenza vaccine strain A/duck/Hokkaido/Vac-1/2004 (H5N1) (Vac-1) was found to be pathogenic in chicken embryos (CEs). In order to decrease the pathogenicity of Vac-1 in CEs, a series of reassortant viruses was generated between Vac-1 and A/Puerto Rico/8/1934 (H1N1) (PR8), and their pathogenicity and growth potential were compared in CEs. The results indicated that either the PB1 or PA protein was responsible for the pathogenicity of Vac-1 in CEs. The HA titers of the allantoic fluids of CEs inoculated with the recombinant H5N1 viruses, of which pathogenicity was lower than that of the recombinant Vac-1 prepared by reverse genetics in CEs, were equivalent to those of CEs inoculated with the recombinant Vac-1. One of the reassortant viruses, rg-PR8-PA/Vac-1 (H5N1), in which the PA gene was replaced with the corresponding gene of PR8, yielded allantoic fluids with the same HA titer as that of Vac-1, indicating that this reassortant should be a good candidate as an improved vaccine strain.
  • Kosuke Soda, Shingo Asakura, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida
    VIROLOGY JOURNAL 8 64  2011年02月 [査読有り][通常論文]
     
    Background: Outbreaks of avian influenza (AI) caused by infection with low pathogenic H9N2 viruses have occurred in poultry, resulting in serious economic losses in Asia and the Middle East. It has been difficult to eradicate the H9N2 virus because of its low pathogenicity, frequently causing in apparent infection. It is important for the control of AI to assess whether the H9N2 virus acquires pathogenicity as H5 and H7 viruses. In the present study, we investigated whether a non-pathogenic H9N2 virus, A/chicken/Yokohama/aq-55/2001 (Y55) (H9N2), acquires pathogenicity in chickens when a pair of di-basic amino acid residues is introduced at the cleavage site of its HA molecule. Results: rgY55sub (H9N2), which had four basic amino acid residues at the HA cleavage site, replicated in MDCK cells in the absence of trypsin after six consecutive passages in the air sacs of chicks, and acquired intravenous pathogenicity to chicken after four additional passages. More than 75% of chickens inoculated intravenously with the passaged virus, rgY55sub-P10 (H9N2), died, indicating that it is pathogenic comparable to that of highly pathogenic avian influenza viruses (HPAIVs) defined by World Organization for Animal Health (OIE). The chickens inoculated with the virus via the intranasal route, however, survived without showing any clinical signs. On the other hand, an avirulent H5N1 strain, A/duck/Hokkaido/Vac-1/2004 (Vac1) (H5N1), acquired intranasal pathogenicity after a pair of di-basic amino acid residues was introduced into the cleavage site of the HA, followed by two passages by air sac inoculation in chicks. Conclusion: The present results demonstrate that an H9N2 virus has the potential to acquire intravenous pathogenicity in chickens although the morbidity via the nasal route of infection is lower than that of H5N1 HPAIV.
  • Naoki Yamamoto, Yoshihiro Sakoda, Masayuki Motoshima, Fumi Yoshino, Kosuke Soda, Masatoshi Okamatsu, Hiroshi Kida
    VIROLOGY JOURNAL 8 65  2011年02月 [査読有り][通常論文]
     
    Background: Infection with H5N1 highly pathogenic avian influenza viruses (HPAIVs) of domestic poultry and wild birds has spread to more than 60 countries in Eurasia and Africa. It is concerned that HPAIVs may be perpetuated in the lakes in Siberia where migratory water birds nest in summer. To monitor whether HPAIVs circulate in migratory water birds, intensive surveillance of avian influenza has been performed in Mongolia and Japan in autumn each year. Until 2008, there had not been any H5N1 viruses isolated from migratory water birds that flew from their nesting lakes in Siberia. In autumn 2009, A/mallard/Hokkaido/24/09 (H5N1) (Mal/Hok/24/09) was isolated from a fecal sample of a mallard (Anas platyrhynchos) that flew from Siberia to Hokkaido, Japan. The isolate was assessed for pathogenicity in chickens, domestic ducks, and quails and analyzed antigenically and phylogenetically. Results: No clinical signs were observed in chickens inoculated intravenously with Mal/Hok/24/09 (H5N1). There was no viral replication in chickens inoculated intranasally with the isolate. None of the domestic ducks and quails inoculated intranasally with the isolate showed any clinical signs. There were no multiple basic amino acid residues at the cleavage site of the hemagglutinin (HA) of the isolate. Each gene of Mal/Hok/24/09 (H5N1) is phylogenetically closely related to that of influenza viruses isolated from migratory water birds that flew from their nesting lakes in autumn. Additionally, the antigenicity of the HA of the isolate was similar to that of the viruses isolated from migratory water birds in Hokkaido that flew from their northern territory in autumn and different from those of HPAIVs isolated from birds found dead in China, Mongolia, and Japan on the way back to their northern territory in spring. Conclusion: Mal/Hok/24/09 (H5N1) is a non-pathogenic avian influenza virus for chickens, domestic ducks, and quails, and is antigenically and genetically distinct from the H5N1 HPAIVs prevailing in birds in Eurasia and Africa. H5 viruses with the HA gene of HPAIV had not been isolated from migratory water birds in the surveillance until 2009, indicating that H5N1 HPAIVs had not become dominant in their nesting lakes in Siberia until 2009.
  • Rozanah Asmah Abdul Samad, Yoshihiro Sakoda, Yoshimi Tsuda, Edgar Simulundu, Rashid Manzoor, Masatoshi Okamatsu, Kimihito Ito, Hiroshi Kida
    JAPANESE JOURNAL OF VETERINARY RESEARCH 59 1 15 - 22 2011年02月 [査読有り][通常論文]
     
    Recent introduction of H5N1 highly pathogenic avian influenza virus (HPAIV) in wild birds from poultry in Eurasia signaled the possibility that this virus may perpetuate in nature. Surveillance of avian influenza especially in migratory birds, therefore, has been conducted to provide information on the viruses brought by them to Hokkaido, Japan, from their nesting lakes in Siberia in autumn. During 2008-2009, 62 influenza viruses of 21 different combinations of hemagglutinin (HA) and neuraminidase (NA) subtypes were isolated. Up to September 2010, no HPAIV has been found, indicating that H5N1 HPAIV has not perpetuated at least dominantly in the lakes where ducks nest in summer in Siberia. The PB2 genes of 54 influenza viruses out of 283 influenza viruses isolated in Hokkaido in 2000-2009 were phylogenetically analysed. None of the genes showed close relation to those of H5N1 HPAIVs that were detected in wild birds found dead in Eurasia on the way back to their northern territory in spring.
  • Rozanah Asmah Abdul Samad, Naoki Nomura, Yoshimi Tsuda, Rashid Manzoor, Masahiro Kajihara, Daisuke Tomabechi, Takashi Sasaki, Norihide Kokumai, Toshiaki Ohgitani, Masatoshi Okamatsu, Ayato Takada, Yoshihiro Sakoda, Hiroshi Kida
    JAPANESE JOURNAL OF VETERINARY RESEARCH 59 1 23 - 29 2011年02月 [査読有り][通常論文]
     
    Inactivated influenza virus vaccine prepared from a non-pathogenic influenza virus strain A/duck/Hokkaido/Vac-1/2004 (H5N1) from the virus library conferred protective immunity to chickens against the challenge of antigenically drifted highly pathogenic avian influenza virus (HPAIV), A/whooper swan/Hokkaido/1/2008 (H5N1). The efficacy of the vaccine was comparable to that prepared from genetically modified HPAIV strain Delta RRRRK rg-A/whooper swan/Mongolia/3/2005 (H5N1), which is more antigenically related to the challenge virus strain, in chickens.
  • Fujiko Minami, Makoto Nagai, Mika Ito, Tatsuhiko Matsuda, Hikaru Takai, Yoshiko Jinkawa, Takeshi Shimano, Michiko Hayashi, Yoshihisa Seki, Yoshihiro Sakoda, Katsuaki Sugiura, Hiroomi Akashi
    COMPARATIVE IMMUNOLOGY MICROBIOLOGY AND INFECTIOUS DISEASES 34 1 35 - 39 2011年01月 [査読有り][通常論文]
     
    Bovine viral diarrhea virus (BVDV) field isolates show genetic and antigenic diversity. At least 14 subgenotypes of BVDV-1 and 4 of BVDV-2 have been identified in Artiodactyla worldwide. Of these, 6 subgenotypes of BVDV-1 and 1 of BVDV-2 have been isolated in Japan. Previously, we reported that each subgenotype virus expresses different antigenic characteristics. Here we investigated the reactivity of neutralizing antibodies against representative strains of Japanese BVDV subgenotypes using sera from 266 beef cattle to estimate the prevalence of this epidemic virus among cattle in Japan. Antibody titers at concentrations at least 4-fold higher than antibodies against other subgenotype viruses were considered subgenotype specific. Subgenotype-specific antibodies were detected from 117(80.7%) of 145 sera samples (69.7% against BVDV-1a, 1.4% against BVDV-1b, 8.3% against BVDV-1c, and 1.4% against BVDV-2a). The results suggest that neutralization tests are useful in estimating currently epidemic subgenotypes of BVDV in the field. (C) 2009 Elsevier Ltd. All rights reserved.
  • Natsumi Takeyama, Kenji Minari, Masahiro Kajihara, Norikazu Isoda, Ryuichi Sakamoto, Takashi Sasaki, Norihide Kokumai, Noriyasu Takikawa, Rikiya Shiraishi, Masaji Mase, Junko Hagiwara, Toshiaki Kodama, Takashi Imamura, Masashi Sakaguchi, Toshiaki Ohgitani, Akira Sawata, Masatoshi Okamatsu, Masatake Muramatsu, Kenji Tsukamoto, Zhifeng Lin, Kotaro Tuchiya, Yoshihiro Sakoda, Hiroshi Kida
    VETERINARY MICROBIOLOGY 147 3-4 283 - 291 2011年01月 [査読有り][通常論文]
     
    H5 and H7 highly pathogenic avian influenza virus (HPAIV) represent a major global concern in poultries and human health. Avian influenza (AI) vaccines are available but not preferred for field applications, primarily because vaccination interferes with sero-surveillances of AIV infection. To overcome the problem, ELISA systems using nonstructural protein 1 (NS1) of AIV as antigens (NS1-ELISA) have been developed to measure anti-NS1 antibodies that are raised in AIV-infected but not in vaccinated chickens. However, some AI-vaccinated chickens having a weak anti-virus immune response may subsequently be infected with AIV and spread the virus. This raises a concern for the validity of NS1-ELISA to detect AIV infection in previously vaccinated chickens. In this study, we developed NS1-ELISA and assessed its feasibility to detect HPAIV infection in chickens previously immunized with H5 or H7 AI vaccines. The results indicated that the NS1-ELISA could identify HPAIV infection in both unvaccinated and vaccinated chickens at 1 week after infection in correlation with results from time-consuming virus isolation tests. Taken together, the NS1-ELISA system would be valuable tool to define HPAIV infection when AI vaccine program is in place. (C) 2010 Elsevier B.V. All rights reserved.
  • Yuko Uchida, Katsushi Kanehira, Masaji Mase, Nobuhiro Takemae, Chiaki Watanabe, Tatsufumi Usui, Yoshikazu Fujimoto, Toshihiro Ito, Manabu Igarashi, Kimihito Ito, Ayato Takada, Yoshihiro Sakoda, Masatoshi Okamatsu, Yu Yamamoto, Kikuyasu Nakamura, Hiroshi Kida, Yasuaki Hiromoto, Tomoyuki Tsuda, Takehiko Saito
    VETERINARY MICROBIOLOGY 147 1-2 1 - 10 2011年01月 [査読有り][通常論文]
     
    From February to March 2009, six strains of H7N6 subtype avian influenza virus were isolated from quails in three farms in Aichi prefecture in Japan. The isolates were shown to be low pathogenic for chicken by the examination performed using the "Manual of Standards for Diagnostic Tests and Vaccines" by World organisation for Animal Health (OIE). The deduced amino acid sequence at the cleavage site was PE (I/Q/L) PKRR (nucleotide sequences were cct gaa (a/c) (t/a) a cc (a/g) aaa aga aga), suggesting persistence in domestic poultry for some time. The direct putative ancestor strain could not be elucidated by phylogenetic analysis of all genome segments of the quail isolates. Diverged date from a putative common ancestor in a non-rooted phylogenetic tree among quail viruses was estimated between March 2002 and July 2004. Three putative N-linked glycosylation sites resided in the vicinity of the receptor binding pocket of HA1 region. They are considered to decrease the reactivity of neutralizing antibody against the virus. Experiments for the infectivity and pathogenicity of a quail strain to poultry indicated that the quail isolate had higher infectivity to quails than chickens and ducks. Direct and dust-borne and/or droplet-borne transmissions among quail were proven in quails with and without direct contact with experimentally infected quails. The virus is seldom transmitted among chickens either directly or indirectly, and indirect transmission from infected quails to chickens was not observed. The pathogenicity of the quail strain for mammalian, pig and mouse was low, although it could replicate in those animals. (C) 2010 Elsevier B.V. All rights reserved.
  • Masatoshi Okamatsu, Tomohisa Tanaka, Naoki Yamamoto, Yoshihiro Sakoda, Takashi Sasaki, Yoshimi Tsuda, Norikazu Isoda, Norihide Kokumai, Ayato Takada, Takashi Umemura, Hiroshi Kida
    VIRUS GENES 41 3 351 - 357 2010年12月 [査読有り][通常論文]
     
    In April and May 2008, whooper swans (Cygnus cygnus) were found dead in Hokkaido in Japan. In this study, an adult whooper swan found dead beside Lake Saroma was pathologically examined and the identified H5N1 influenza virus isolates were genetically and antigenically analyzed. Pathological findings indicate that the swan died of severe congestive edema in the lungs. Phylogenetic analysis of the HA genes of the isolates revealed that they are the progeny viruses of isolates from poultry and wild birds in China, Russia, Korea, and Hong Kong. Antigenic analyses indicated that the viruses are distinguished from the H5N1 viruses isolated from wild birds and poultry before 2007. The chickens vaccinated with A/duck/Hokkaido/Vac-1/2004 (H5N1) survived for 14 days after challenge with A/whooper swan/Hokkaido/1/2008 (H5N1), although a small amount of the challenge virus was recovered from the tissues of the birds. These findings indicate that H5N1 highly pathogenic avian influenza viruses are circulating in wild birds in addition to domestic poultry in Asia and exhibit antigenic variation that may be due to vaccination.
  • Yoshihiro Sakoda, Sengee Sugar, Damdinjav Batchluun, Tseren-Ochir Erdene-Ochir, Masatoshi Okamatsu, Norikazu Isoda, Kosuke Soda, Hiroki Takakuwa, Yoshimi Tsuda, Naoki Yamamoto, Noriko Kishida, Keita Matsuno, Eri Nakayama, Masahiro Kajihara, Ayaka Yokoyama, Ayato Takada, Ruuragchaa Sodnomdarjaa, Hiroshi Kida
    VIROLOGY 406 1 88 - 94 2010年10月 [査読有り][通常論文]
     
    H5N1 highly pathogenic avian influenza (HPAI) viruses were isolated from dead wild waterfowl at Khunt, Erkhel, Doityn Tsagaan, Doroo, and Ganga Lakes in Mongolia in July 2005, May 2006, May 2009, July 2009, and May 2010, respectively. The isolates in 2005 and 2006 were classified into genetic clade 2.2, and those in 2009 and 2010 into clade 2.3.2. A/whooper swan/Mongolia/6/2009 (H5N1) experimentally infected ducks and replicated systemically with higher mortality than that of the isolates in 2005 and 2006. Intensive surveillance of avian influenza in migratory waterfowl flying from their nesting lakes in Siberia to Mongolia in every autumn indicate that HPAI viruses have not perpetuated at their nesting lakes until 2009. The present results demonstrate that wild waterfowl were sporadically infected with H5N1 HPAI viruses prevailing in domestic poultry in the southern Asia and died in Mongolia on the way back to their northern territory in spring. (C) 2010 Elsevier Inc. All rights reserved.
  • Kazuya Matsuda, Shintaro Kobayashi, Ken-ichiro Kameyama, Michiko Sato, Masateru Koiwa, Yoshihiro Sakoda, Hiroyuki Taniyama
    JOURNAL OF VETERINARY MEDICAL SCIENCE 72 7 903 - 907 2010年07月 [査読有り][通常論文]
     
    Bovine viral diarrhea virus (BVDV) causes fetal brain malformations in ruminants when the fetuses are infected transplacentally in mid-pregnancy. In both cytopathic and non-cytopatic virus infections, viral lytic infection in actively replicating cells and interruption of vascular integrity have been suggested as the pathogenesis, but functional disturbance of infected neural developing cells has been unclear. In this study, we examined the effect of infection with non-cytopathic BVDV2 on the differentiation of neural stem/precursor cells isolated from the bovine fetus. In the process of differentiation to three types of neural cells, neurons, astrocytes and oligodendrocytes, virus infection significantly and selectively inhibited the differentiation of neural stem/precursor cells into the astrocytic lineage. This inhibition is possibly important for the pathogenesis of congenital brain malformations associated with non-cytopathic BVDV infection.
  • Takashi Sasaki, Norihide Kokumai, Toshiaki Ohgitani, Takashi Imamura, Akira Sawata, Zhifeng Lin, Yoshihiro Sakoda, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 72 6 819 - 821 2010年06月 [査読有り][通常論文]
     
    It is known that antibody responses in chickens against invading organisms or antigens are considerably different among different lines. Thus, an avian influenza vaccine was prepared from inactivated whole particles of the virus of non-pathogenic strain A/duck/Hokkaido/Vac-1/04 (H5N1) using an oil adjuvant containing anhydromannitol-octadecenoate-ether and injected intramuscularly into each ten 10-week-old specific pathogen-free (SPF) white leghorn chickens and commercial layers of Julia and Boris-Brown to obtain comparative data for antibody responses until 6 weeks after vaccination. Despite significant partial differences of antibody titer between the chicken lines, this study clearly showed that the vaccine induced good and sufficient antibody response in both SPF chickens and commercial layers.
  • Fei Feng, Nobuaki Miura, Norikazu Isoda, Yoshihiro Sakoda, Masatoshi Okamatsu, Hiroshi Kida, Shin-Ichiro Nishimura
    BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 20 12 3772 - 3776 2010年06月 [査読有り][通常論文]
     
    We designed and synthesized novel trivalent anti-influenza reagents. Sialyllactose was located at the terminal of each valence which aimed to block each receptor-binding site of the hemagglutinin (HA) trimer on the surface of the virus. Structural analyses were carried out with a model which was constructed with a computer simulation. A previously reported cyclic glycopeptide blocker [Ohta, T.; Miura, N.; Fujitani, N.; Nakajima, F.; Niikura, K.; Sadamoto, R.; Guo, C.-T.; Suzuki, T.; Suzuki, Y.; Monde, K.; Nishimura, S.-I. Angew. Chem. Int. Ed., 2003, 42, 5186] bound to the HA in the model. The analyses suggest that the glutamine residue in the cyclic peptide bearing Neu5A alpha 2,3Gal beta 1,4Glc trisaccharide via a linker interacts with the Gln189 in HA through hydrogen bonding. The present anti-influenza reagents likely interact with a glutamine residue included in the vicinity of Gln189. A plague reduction assay of the influenza virus, A/PR/8/1934 (H1N1),was performed in MDCK cells to evaluate for the synthesized compounds to inhibit viral replication. One of the compounds showed approximately 85% inhibition at the concentration of 400 mu M at 4 degrees C. (C) 2010 Elsevier Ltd. All rights reserved.
  • Ming-Chu Cheng, Kosuke Soda, Ming-Shiuh Lee, Shu-Hwae Lee, Yoshihiro Sakoda, Hiroshi Kida, Ching-Ho Wang
    AVIAN DISEASES 54 2 885 - 893 2010年06月 [査読有り][通常論文]
     
    During the surveillance of avian influenza, an H5N2 influenza A virus was isolated from a cloacal swab sample of an apparently healthy chicken in Taiwan in October 2008. It was found that the HA of the virus had a pair of dibasic amino acid residues at the cleavage site, which might be a marker of highly pathogenic avian influenza virus. However, the intravenous pathogenicity index of the isolate was 0.89, indicating that the virus was approaching high pathogenicity in chickens. Virus isolation was negative in 2916 birds from 146 farms in a 3-km radius around the farm where the virus was isolated. Genetic analysis of the eight segments of the isolate indicated that the isolated virus was a reassortant whose HA and NA gene segments belonged to the American lineage and internal genes to the Eurasian lineage.
  • Tomohisa Tanaka, Yuji Sunden, Yoshihiro Sakoda, Hiroshi Kida, Kenji Ochiai, Takashi Umemura
    JOURNAL OF NEUROVIROLOGY 16 2 125 - 132 2010年04月 [査読有り][通常論文]
     
    Influenza virus-associated encephalopathy (IAE) is a highly mortal neural complication of influenza A virus (IAV) infection, mostly affecting children younger than 5 years old, and the brain pathology of IAE is characterized by peracute brain edema with evidence of an impaired blood-brain barrier. The pathogenesis of IAE is unknown, but hypercytokinemia of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, and IL-6 is suspected of playing a central role in the development of IAE. Because the brain pathology of IAE is similar to that of septic encephalopathy due to endotoxemia, the effect of combined treatment of IAV and lipopolysaccharide (LPS) was tested using suckling mice. The results show that pulmonary infection with non-neurotropic IAV enhanced the neuropathogenicity of LPS and induced encephalopathy that was similar to IAE with respect to the occurrence of central nervous system (CNS) histopathology and the absence of direct infection of IAV in the brain. Influenza A virus also increased blood-brain barrier (BBB) permeability and induced inflammatory cytokines in the blood. These results suggested that the mice treated with IAV+LPS are possible animal models of IAE, and that hypercytokinemia and/or the involvement of endotoxemia in IAV infection are possible causes of IAE.
  • Taichiro Miyake, Kosuke Soda, Yasushi Itoh, Yoshihiro Sakoda, Hirohito Ishigaki, Tomoya Nagata, Hideaki Ishida, Misako Nakayama, Hiroichi Ozaki, Hideaki Tsuchiya, Ryuzo Torii, Hiroshi Kida, Kazumasa Ogasawara
    JOURNAL OF MEDICAL PRIMATOLOGY 39 1 58 - 70 2010年02月 [査読有り][通常論文]
     
    Background Highly pathogenic avian influenza virus (HPAIV) infection has a high mortality rate in humans. Secondary bacterial pneumonia with HPAIV infection has not been reported in human patients, whereas seasonal influenza viruses sometimes enhance bacterial pneumonia, resulting in substantial morbidity and mortality. Therefore, if HPAIV infection were accompanied by bacterial infection, an increase in mortality would be expected. We examined whether a vaccine against HPAIV prevents severe morbidity caused by mixed infection with HPAIV and bacteria. Methods H7N7 subtype of HPAIV and Streptococcus pneumoniae were inoculated into cynomolgus macaques with or without vaccination of inactivated whole virus particles. Results Vaccination against H7N7 HPAIV decreased morbidity caused by HPAIV and pneumonia caused by S. pneumoniae. Bacterial replication in lungs was decreased by vaccination against HPAIV, although the reduction in bacterial colonies was not significant. Conclusions Vaccination against HPAIV reduces pneumonia caused by bacterial superinfection and may improve prognosis of HPAIV-infected patients.
  • Yasushi Itoh, Hiroichi Ozaki, Hirohito Ishigaki, Yoshihiro Sakoda, Tomoya Nagata, Kosuke Soda, Norikazu Isoda, Taichiro Miyake, Hideaki Ishida, Kiyoko Okamoto, Misako Nakayama, Hideaki Tsuchiya, Ryuzo Torii, Hiroshi Kida, Kazumasa Ogasawara
    VACCINE 28 3 780 - 789 2010年01月 [査読有り][通常論文]
     
    Development of H7N7 highly pathogenic avian influenza virus (HPAIV) vaccines is an urgent issue since human cases of infection with this subtype virus have been reported and most humans have no immunity against H7N7 viruses. We made an H7N7 vaccine combining components from an influenza virus library of non-pathogenic type A influenza viruses Antibody and T cell recall responses specific against the vaccine strain were elicited by subcutaneous inoculation with the whole virus particle vaccine with or without alum as an adjuvant in cynomolgus macaques. No significant difference was observed in magnitude of antibody responses between vaccination with alum and vaccination without alum, though vaccination with alum induced longer recall responses of CD8(+) T cells than did vaccination without alum. After challenge with a subtype of H7N7 HPAIV, the virus was detected in nasal swabs of unvaccinated macaques for 8 days but only for I day in the animals vaccinated either with or without alum, although the macaques vaccinated with alum showed elevated body temperature more briefly after infection. These findings demonstrated that this H7N7 HPAIV strain is pathogenic to macaques and that the vaccine conferred protective immunity to macaques against H7N7 HPAIV infection. (C) 2009 Elsevier Ltd. All rights reserved.
  • Yoshitaka Kashima, Mizuho Ikeda, Yasushi Itoh, Yoshihiro Sakoda, Tomoya Nagata, Taichiro Miyake, Kosuke Soda, Hiroichi Ozaki, Misako Nakayama, Hitomi Shibuya, Masatoshi Okamatsu, Hirohito Ishigaki, Hideaki Ishida, Toshihiro Sawai, Yoshihiro Kawaoka, Hiroshi Kida, Kazumasa Ogasawar
    VACCINE 27 52 7402 - 7408 2009年12月 [査読有り][通常論文]
     
    Outbreaks of highly pathogenic avian influenza viruses (HPAIVs) would cause disasters worldwide. Various strategies against HPAIVs are required to control damage. it is thought that the use of non-pathogenic avian influenza viruses as live vaccines will be effective in an emergency, even though there might be some adverse effects, because small amounts of live vaccines will confer immunity to protect against HPAIV infection. Therefore, live vaccines have the advantage of being able to be distributed worldwide soon after an outbreak. In the present study, we found that intranasal administration of a live H5N1 subtype non-pathogenic virus induced antibody and cytotoxic T lymphocyte responses and protected mice against H5N1 HPAIV infection. In addition, it was found that a small amount (100 PFU) of the live vaccine was as effective as 100 mu g (approximately 10(10-11) PFU of virus particles)of the inactivated whole particle vaccine in mice. Consequently, the use of live virus vaccines might be one strategy for preventing pandemics of HPAIVs in an emergency. (C) 2009 Elsevier Ltd. All rights reserved.
  • Manuela Ocana-Macchi, Michael Bel, Laurence Guzylack-Piriou, Nicolas Ruggli, Matthias Liniger, Kenneth C. McCullough, Yoshihiro Sakoda, Norikazu Isoda, Mikhail Matrosovich, Artur Summerfield
    JOURNAL OF VIROLOGY 83 24 12947 - 12955 2009年12月 [査読有り][通常論文]
     
    Although current H5N1 highly pathogenic avian influenza viruses (HPAIV) are inefficiently transmitted to humans, infected individuals can suffer from severe disease, often progressing rapidly to acute respiratory distress syndrome and multiorgan failure. This is in contrast with the situation with human influenza viruses, which in immunocompetent individuals usually cause only a respiratory disease which is less aggressive than that observed with avian H5N1 viruses. While the biological basis of inefficient transmission is well documented, the mechanisms by which the H5N1 viruses cause fatal disease remain unclear. In the present study, we demonstrate that human pulmonary microvascular endothelial cells (hPMEC) had a clearly higher susceptibility to infection by H5N1 HPAIV than to infection by human influenza viruses. This was measurable by de novo intracellular nucleoprotein production and virus replication. It was also related to a relatively higher binding capacity to cellular receptors. After infection of hPMEC, cell activation markers E-selectin and P-selectin were upregulated, and the proinflammatory cytokines interleukin-6 and beta interferon were secreted. H5N1 virus infection was also associated with an elevated rate of cell death. Reverse genetics analyses demonstrated a major role for the viral hemagglutinin in this cell tropism. Overall, avian H5N1 viruses have a particular receptor specificity targeting endothelial cells that is different from human influenza viruses, and this H5N1 receptor specificity could contribute to disease pathogenesis.
  • Jae-Ho Shin, Yoshihiro Sakoda, Shiori Yano, Kenji Ochiai, Hiroshi Kida, Takashi Umemura
    JOURNAL OF VETERINARY MEDICAL SCIENCE 71 10 1331 - 1336 2009年10月 [査読有り][通常論文]
     
    To evaluate the efficacy of intracerebral (IC) immunization, mice were immunized with a rabies vaccine by the subcutaneous (SC), intramuscular (IM) or IC route, and 10-fold the 50% lethal dose of rabies virus was inoculated into the hindleg of the immunized or non-immunized mice. The antibody titer in serum was elevated and boosted by additional immunization via all routes, but highest after the IC immunization followed by the IM and SC routes, in this order. Intracerebrally immunized mice were completely protected from death and the neurological signs of infection, whereas the IM or SC immunization only partly protected the mice. In mouse models, IC immunization is more effective at inducing a protective immune response against the transneural spread of rabies virus than IM or SC immunization.
  • Takashi Sasaki, Norihide Kokumai, Toshiaki Ohgitani, Ryuichi Sakamoto, Noriyasu Takikawa, Zhifeng Lin, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida
    VACCINE 27 38 5174 - 5177 2009年08月 [査読有り][通常論文]
     
    An influenza vaccine was prepared from inactivated whole particles of the non-pathogenic strain A/duck/Hokkaido/Vac-1/04 (H5N1) virus using an oil adjuvant containing anhydromannitol-octaclecenoate-ether (AMOE). The vaccine was injected intramuscularly into five 4-week-old chickens, and 138 weeks after vaccination, they were challenged intranasally with 100 times 50% chicken lethal dose of the highly pathogenic avian influenza (HPAI) virus A/chicken/Yamaguchi/7/04 (H5N1). All 5 chickens survived without exhibiting clinical signs of influenza, although 2 days post-challenge, 3 vaccinated chickens shed limited titres of viruses in laryngopharyngeal swabs. (C) 2009 Elsevier Ltd. All rights reserved.
  • Yasushi Itoh, Kyoko Shinya, Maki Kiso, Tokiko Watanabe, Yoshihiro Sakoda, Masato Hatta, Yukiko Muramoto, Daisuke Tamura, Yuko Sakai-Tagawa, Takeshi Noda, Saori Sakabe, Masaki Imai, Yasuko Hatta, Shinji Watanabe, Chengjun Li, Shinya Yamada, Ken Fujii, Shin Murakami, Hirotaka Imai, Satoshi Kakugawa, Mutsumi Ito, Ryo Takano, Kiyoko Iwatsuki-Horimoto, Masayuki Shimojima, Taisuke Horimoto, Hideo Goto, Kei Takahashi, Akiko Makino, Hirohito Ishigaki, Misako Nakayama, Masatoshi Okamatsu, Kazuo Takahashi, David Warshauer, Peter A. Shult, Reiko Saito, Hiroshi Suzuki, Yousuke Furuta, Makoto Yamashita, Keiko Mitamura, Kunio Nakano, Morio Nakamura, Rebecca Brockman-Schneider, Hiroshi Mitamura, Masahiko Yamazaki, Norio Sugaya, M. Suresh, Makoto Ozawa, Gabriele Neumann, James Gern, Hiroshi Kida, Kazumasa Ogasawara, Yoshihiro Kawaoka
    NATURE 460 7258 1021 - U110 2009年08月 [査読有り][通常論文]
     
    Influenza A viruses cause recurrent outbreaks at local or global scale with potentially severe consequences for human health and the global economy. Recently, a new strain of influenza A virus was detected that causes disease in and transmits among humans, probably owing to little or no pre-existing immunity to the new strain. On 11 June 2009 the World Health Organization declared that the infections caused by the new strain had reached pandemic proportion. Characterized as an influenza A virus of the H1N1 subtype, the genomic segments of the new strain were most closely related to swine viruses(1). Most human infections with swine-origin H1N1 influenza viruses (S-OIVs) seem to be mild; however, a substantial number of hospitalized individuals do not have underlying health issues, attesting to the pathogenic potential of S-OIVs. To achieve a better assessment of the risk posed by the new virus, we characterized one of the first US S-OIV isolates, A/California/04/09 ( H1N1; hereafter referred to as CA04), as well as several other S-OIV isolates, in vitro and in vivo. In mice and ferrets, CA04 and other S- OIV isolates tested replicate more efficiently than a currently circulating human H1N1 virus. In addition, CA04 replicates efficiently in non-human primates, causes more severe pathological lesions in the lungs of infected mice, ferrets and non-human primates than a currently circulating human H1N1 virus, and transmits among ferrets. In specific-pathogen-free miniature pigs, CA04 replicates without clinical symptoms. The assessment of human sera from different age groups suggests that infection with human H1N1 viruses antigenically closely related to viruses circulating in 1918 confers neutralizing antibody activity to CA04. Finally, we show that CA04 is sensitive to approved and experimental antiviral drugs, suggesting that these compounds could function as a first line of defence against the recently declared S- OIV pandemic.
  • Kanako Moritoh, Hideto Yamauchi, Atsushi Asano, Kentaro Yoshii, Hiroaki Kariwa, Ikuo Takashima, Norikazu Isoda, Yoshihiro Sakoda, Hiroshi Kida, Nobuya Sasaki, Takashi Agui
    JAPANESE JOURNAL OF VETERINARY RESEARCH 57 2 89 - 99 2009年08月 [査読有り][通常論文]
     
    Mx1 (Myxovirus resistance protein) and Oas1b (Oligoadenylate synthetase-1), induced by type 1 interferon (IFN), play a role in early antiviral innate immunity by inhibiting the replication of viruses. In mice, Mx1 and Oas1b confer resistance to the infection of orthomyxoviruses including influenza viruses and flaviviruses including West Nile viruses, respectively. Laboratory mice have been used to study the mechanisms of the pathogenesis of these virus infections; however, it is possible that they are not a suitable model system to study these viruses, since most of the inbred laboratory mouse strains lack both genes. It has been reported that feral mouse-derived inbred strains show resistance to the infection of these viruses due to the presence of intact both genes. In this study, we generated congenic strains in which the Mx or Oas locus of the MSM/Ms (MSAI) mouce was introduced to the most widely used mouse strain, C57BL/6J (136). B6.MSM-Mx mice showed resistance to the infection of influenza virus but not of West Nile virus. On the other hand, B6.MSM-Oas mice showed resistance to the infection of West Nile virus but not of influenza virus. Our results indicate that Mx1 and Oas1b show highly antiviral specificity in mice possessing the same genetic background. Therefore, these congenic mice are useful for not only infection study but also investigation of host defense mechanism to these viruses.
  • Yoko Hara, Rie Hasebe, Yuji Sunden, Kenji Ochia, Eiichi Honda, Yoshihiro Sakoda, Takashi Umemura
    JOURNAL OF VETERINARY MEDICAL SCIENCE 71 5 595 - 601 2009年05月 [査読有り][通常論文]
     
    Swine hemagglutinating encephalomyelitis virus (HEV) causes encephalomyelitis or vomiting and wasting disease in Suckling piglets. Neurotoropism of the virus has been demonstrated in previous in vivo studies. In the present study, we investigated the infectivity and propagation of HEV in comparison with those of pseudorabies virus (PRV), another neurotropic virus, using dorsal root ganglia cells of newborn mice containing nerve cells and non-neuronal cells. HEV infected nerve cells but did not infect non-neuronal cells, whereas PRV infected both cell types. By using cytoskeletal inhibitors, it was Suggested that propagation of HEV and PRV within and among nerve cells depended on microtubules and intermediate filaments of nerve cells, indicating that the viruses may be transported between the cell body and axonal terminals of neurons by fast axonal flow.
  • Yoshimi Tsuda, Norikazu Isoda, Yoshihiro Sakoda, Hiroshi Kida
    VIRUS RESEARCH 140 1-2 194 - 198 2009年03月 [査読有り][通常論文]
     
    Many influenza A viruses form plaques on Madin-Darby canine kidney (MDCK) cells in the presence of trypsin. A/duck/Siberia/272/1998 (H13N6) (Sib272), however, does not form plaque on MDCK cells. After three blind passages of the strain on MDCK cells, plaque-forming variant was obtained and designated as A/duck/Siberia/272PF/1998 (H13N6) (Sib272PF). Genetic and functional analyses of Sib272 and Sib272PF revealed that amino acid substitutions, F3L of the HA2 subunit and T379K of the PB1, were responsible for plaque formation of Sib272PF by enhancing fusion and polymerase activities, respectively. (c) 2009 Elsevier B.V. All rights reserved.
  • Rashid Manzoor, Yoshihiro Sakoda, Naoki Nomura, Yoshimi Tsuda, Hiroichi Ozaki, Masatoshi Okamatsu, Hiroshi Kida
    JOURNAL OF VIROLOGY 83 4 1572 - 1578 2009年02月 [査読有り][通常論文]
     
    It has been shown that not all but most of the avian influenza viruses replicate in the upper respiratory tract of pigs (H. Kida et al., J. Gen. Virol. 75: 2183-2188, 1994). It was shown that A/chicken/Yamaguchi/7/2004 (H5N1) [Ck/Yamaguchi/04 (H5N1)] did not replicate in pigs (N. Isoda et al., Arch. Virol. 151: 1267-1279, 2006). In the present study, the genetic basis for this host range restriction was determined using reassortant viruses generated between Ck/Yamaguchi/04 (H5N1) and A/swine/Hokkaido/2/1981 (H1N1) [Sw/Hokkaido/81 (H1N1)]. Two in vivo-generated single-gene reassortant virus clones of the H5N1 subtype (virus clones 1 and 2), whose PB2 gene was of Sw/Hokkaido/81 (H1N1) origin and whose remaining seven genes were of Ck/Yamaguchi/04 (H5N1) origin, were recovered from the experimentally infected pigs. The replicative potential of virus clones 1 and 2 was further confirmed by using reassortant virus (rg-Ck-Sw/PB2) generated by reverse genetics. Interestingly, the PB2 gene of Ck/Yamaguchi/04 (H5N1) did not restrict the replication of Sw/Hokkaido/81 (H1N1), as determined by using reassortant virus rg-Sw-Ck/PB2. The rg-Sw-Ck/PB2 virus replicated to moderate levels and for a shorter duration than parental Sw/Hokkaido/81 (H1N1). Sequencing of two isolates recovered from the pigs inoculated with rg-Sw-Ck/PB2 revealed either the D256G or the E627K amino acid substitution in the PB2 proteins of the isolates. The D256G and E627K mutations enhanced viral polymerase activity in the mammalian cells, correlating with replication of virus in pigs. These results indicate that the PB2 protein restricts the growth of Ck/Yamaguchi/04 (H5N1) in pigs.
  • Takashi Sasaki, Norikazu Isoda, Kosuke Soda, Ryuichi Sakamoto, Kazue Saijo, Junko Hagiwara, Norihide Kokumai, Toshiaki Ohgitani, Takashi Imamura, Akira Sawata, Zhifeng Lin, Yoshihiro Sakoda, Hiroshi Kida
    JAPANESE JOURNAL OF VETERINARY RESEARCH 56 4 189 - 198 2009年02月 [査読有り][通常論文]
     
    Test vaccines comprised of inactivated water-in-oil emulsions containing various antigen levels were prepared using a non-pathogenic H5N1 avian influenza (AI) virus, A/duck/Hokkaido/Vac-1/04 (H5N1). The potencies of these test vaccines were evaluated by two experiments. In the first experiment, the triangular relationship among the antigen levels of test vaccines, the hemagglutination inhibition (HI) antibody response, and the protective effect against challenge with a highly pathogenic avian influenza (HPAI) virus, A/chicken/Yamaguchi/7/04 (H5N1), was confirmed. Then lasting immunity of chickens after a single-shot vaccination was confirmed in the second experiment. As a result, complete protection after the challenge was observed in chickens immunized by test vaccines with an antigen level of 160 HA units/dose or higher. Thus, it was ascertained that the minimum antigen level in the AI vaccine was 160 RA units/dose, and the minimum HI antibody titer that could protect chickens from HPAI virus infection-related death was considered to be 1:16. Dose-dependent III antibody responses were observed in chickens after the vaccination. Thus, 640 RA units/dose was thought to be similar to the optimal antigen level. Alternatively, the HI antibody titers of chickens, injected with the vaccine containing 640 HA units/dose, were maintained at 1:181 or higher for 100 weeks after the single-shot vaccination.
  • Nicolas Ruggli, Artur Summerfield, Ana R. Fiebach, Laurence Guzylack-Piriou, Oliver Bauhofer, Catherine G. Lamm, Sandro Waltersperger, Keita Matsuno, Luzia Liu, Markus Gerber, Kyung H. Choi, Martin A. Hofmann, Yoshihiro Sakoda, Jon-Duri Tratschin
    JOURNAL OF VIROLOGY 83 2 817 - 829 2009年01月 [査読有り][通常論文]
     
    Pestiviruses prevent alpha/beta interferon (IFN-alpha/beta) production by promoting proteasomal degradation of interferon regulatory factor 3 (IRF3) by means of the viral N-pro nonstructural protein. N-pro is also an autoprotease, and its amino-terminal coding sequence is involved in translation initiation. We previously showed with classical swine fever virus (CSFV) that deletion of the entire N-pro gene resulted in attenuation in pigs. In order to elaborate on the role of the N-pro-mediated IRF3 degradation in classical swine fever pathogenesis, we searched for minimal amino acid substitutions in N-pro that would specifically abrogate this function. Our mutational analyses showed that degradation of IRF3 and autoprotease activity are two independent but structurally overlapping functions of N-pro. We describe two mutations in N-pro that eliminate N-pro-mediated IRF3 degradation without affecting the autoprotease activity. We also show that the conserved standard sequence at these particular positions is essential for N-pro to interact with IRF3. Surprisingly, when these two mutations are introduced independently in the backbones of highly and moderately virulent CSFV, the resulting viruses are not attenuated, or are only partially attenuated, in 8- to 10-week-old pigs. This contrasts with the fact that these mutant viruses have lost the capacity to degrade IRF3 and to prevent IFN-alpha/beta induction in porcine cell lines and monocyte-derived dendritic cells. Taken together, these results demonstrate that contrary to previous assumptions and to the case for other viral systems, impairment of IRF3-dependent IFN-alpha/beta induction is not a prerequisite for CSFV virulence.
  • Masatoshi Okamatsu, Yoshihiro Sakoda, Noriko Kishida, Norikazu Isoda, Hiroshi Kida
    ARCHIVES OF VIROLOGY 153 12 2189 - 2195 2008年12月 [査読有り][通常論文]
     
    The hemagglutinins (HAs) of H9 influenza viruses isolated from birds and mammals of different species were antigenically and genetically analyzed. Antigenic variants were selected from A/swine/Hong Kong/10/98 (H9N2) and A/duck/Hokkaido/13/00 (H9N2) in the presence of monoclonal antibodies (MAbs). Based on the reactivity patterns of these mutants with a panel of MAbs, at least five non-overlapping antigenic sites were defined using eight MAbs which recognized seven distinct epitopes on the H9 HA molecule. Based on the reactivity patterns with the panel of monoclonal antibodies, 21 H9N2 virus strains isolated from birds and mammals were divided into 7 antigenically distinct groups. The present findings indicate that it is important to monitor the antigenic variation in H9 influenza viruses. The panel of MAbs in the present study, thus, should be useful for detailed antigenic analysis of the H9 HAs for epidemiological studies, the selection of vaccine strains, and diagnosis.
  • Kosuke Soda, Hiroichi Ozaki, Yoshihiro Sakoda, Norikazu Isoda, Yoshinari Haraguchi, Saori Sakabe, Noritaka Kuboki, Noriko Kishida, Ayato Takada, Hiroshi Kida
    ARCHIVES OF VIROLOGY 153 11 2041 - 2048 2008年11月 [査読有り][通常論文]
     
    In order to prepare H5N1 influenza virus vaccine, the hemagglutinins (HAs) of 14 H5 virus isolates from water birds in Asia were antigenically and genetically analyzed. Phylogenetic analysis of the H5 HA genes revealed that 13 isolates belong to Eurasian and the other one to North American lineages. Each of the deduced amino acid sequences of the HAs indicated a non-pathogenic profile. Antigenic analysis using a panel of monoclonal antibodies recognizing six different epitopes on the HA of A/duck/Pennsylvania/10218/1984 (H5N2) and chicken antiserum to an H5N1 reassortant strain generated between A/duck/Mongolia/54/2001 (H5N2) and A/duck/Mongolia/47/2001 (H7N1), [R(Dk/Mong-Dk/Mong) (H5N1)] showed that the HAs of highly pathogenic avian influenza (HPAI) viruses currently circulating in Asia were antigenically closely related to those of the present isolates from water birds. Mice subcutaneously injected with formalin-inactivated R(Dk/Mong-Dk/Mong) were protected from challenge with 100 mouse lethal dose of A/Viet Nam/1194/2004 (H5N1). The present results support the notion that the H5 isolates and the reassortant H5N1 strain should be useful for vaccine preparation.
  • Rashid Manzoor, Yoshihiro Sakoda, Aaron Mweene, Yoshimi Tsuda, Noriko Kishida, Gui-Rong Bai, Ken-Ichiro Kameyama, Norikazu Isoda, Kosuke Soda, Michiko Naito, Hiroshi Kida
    VIRUS GENES 37 2 144 - 152 2008年10月 [査読有り][通常論文]
     
    During 2000-2007, 218 influenza viruses of 28 different combinations of HA (H1-H13) and NA (N1-N9) subtypes were isolated from fecal samples of free-flying water birds at two distant lakes in Hokkaido, Japan. Phylogenic analysis of the matrix (M) genes of 67 strains, selected on the basis of their subtype combinations, revealed that A/duck/Hokkaido/W95/2006 (H10N8) was a reassortant whose M gene belonged to North American non-gull-avian and the other seven genes to Eurasian non-gull-avian lineages. The M genes of other 65 strains belonged to Eurasian non-gull-avian and the one to Eurasian-gull lineages. The M genes of 65 strains were grouped into three different sublineages, indicating that influenza viruses circulating in different populations of free-flying water birds have evolved independently in nature.
  • Rashid Manzoor, Yoshihiro Sakoda, Aaron Mweene, Yoshimi Tsuda, Noriko Kishida, Gui-Rong Bai, Ken-Ichiro Kameyama, Norikazu Isoda, Kosuke Soda, Michiko Naito, Hiroshi Kida
    Virus Genes 37 2 153  2008年10月 [査読有り][通常論文]
  • Norikazu Isoda, Yoshihiro Sakoda, Noriko Kishida, Kosuke Soda, Saori Sakabe, Ryuichi Sakamoto, Takashi Imamura, Masashi Sakaguchi, Takashi Sasaki, Norihide Kokumai, Toshiaki Ohgitani, Kazue Saijo, Akira Sawata, Junko Hagiwara, Zhifeng Lin, Hiroshi Kida
    ARCHIVES OF VIROLOGY 153 9 1685 - 1692 2008年09月 [査読有り][通常論文]
     
    A reassortant influenza virus, A/duck/Hokkaido/Vac-1/2004 (H5N1) (Dk/Vac-1/04), was generated between non-pathogenic avian influenza viruses isolated from migratory ducks in Asia. Dk/Vac-1/04 (H5N1) virus particles propagated in embryonated chicken eggs were inactivated with formalin and adjuvanted with mineral oil to form a water-in-oil emulsion. The resulting vaccine was injected intramuscularly into chickens. The chickens were challenged with either of the highly pathogenic avian influenza virus strains A/chicken/Yamaguchi/7/2004 (H5N1) or A/swan/Mongolia/3/2005 (H5N1) at 21 days post-vaccination (p. v.), when the geometric mean serum HI titers of the birds was 64 with the challenge virus strains. The vaccinated chickens were protected from manifestation of disease signs upon challenge with either of the highly pathogenic avian influenza viruses. However, challenge virus was recovered at low titers from the birds at 2 and 4 days post-challenge (p.c.). All 3 chickens challenged at 6 days p.v. died, whereas 3 chickens challenged at 8 days p.v. survived. These results indicate that the present vaccine confers clinical protection and reduction of virus shedding against highly pathogenic avian influenza virus challenge and should be useful as an optional tool in emergency cases.
  • Mika Ito, Makoto Nagai, Yuji Hayakawa, Hirofumi Komae, Naruto Murakami, Syouichi Yotsuya, Shingo Asakura, Yoshihiro Sakoda, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 70 9 899 - 906 2008年09月 [査読有り][通常論文]
     
    In August 2007, an outbreak of equine influenza occurred among vaccinated racehorses with Japanese commercial equine influenza vaccine at Kanazawa Racecourse in Ishikawa prefecture in Japan. Apparent symptoms were pyrexia (38.2-41.0 degrees C) and nasal discharge with or without coughing, although approximately half of the infected horses were subclinical. All horses had been shot with a vaccine that contained two inactivated H3N8 influenza virus strains [A/equine/La Plata/93 (La Plata/93) of American lineage and A/ equine/Avesta/93 (Avesta/93) of European lineage] and an H7N7 strain (A/equine/Newmarket/1/77). Influenza virus, A/equine/ Kanazawa/1/2007 (H3N8) (Kanazawa/07), was isolated from one of the nasal swab samples of diseased horses. Phylogenetic analysis indicated that Kanazawa/07 was classified into the American sublineage Florida. In addition, four amino acid substitutions were found in the antigenic sites B and E in the HA1 subunit protein of Kanazawa/07 in comparison with that of La Plata/93. Hemagglutination-inhibition (HI) test using 16 serum samples from recovering horses revealed that 1.4- to 8-fold difference in titers between Kanazawa/ 07 and either of the vaccine strains. The present findings suggest that Japanese commercial inactivated vaccine contributed to reducing the morbidity rate and manifestation of the clinical signs of horses infected with Kanazawa/07 that may be antigenically different from the vaccine strains.
  • Noriko Kishida, Yoshihiro Sakoda, Mai Shiromoto, Gui-Rong Bai, Norikazu Isoda, Ayato Takada, Graeme Laver, Hiroshi Kida
    VIRUS GENES 37 1 16 - 21 2008年08月 [査読有り][通常論文]
     
    To investigate the prevalence of influenza viruses in feral water birds in the Southern Hemisphere, fecal samples of terns were collected on Heron Island, Australia, in December 2004. Six H2N5 influenza viruses were isolated. This is the first report of the isolation of the H2 subtype from shore birds in Australia. Phylogenetic analysis revealed that the M gene belonged to the American lineage of avian influenza viruses and the other genes belonged to the Eurasian lineages, indicating that genetic reassortment occurs between viruses of Eurasian and American lineages in free flying birds in nature.
  • Rashid Manzoor, Yoshihiro Sakoda, Saori Sakabe, Tsuyoshi Mochizuki, Yasuharu Namba, Yoshimi Tsuda, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 70 6 557 - 562 2008年06月 [査読有り][通常論文]
     
    As well as H5 highly pathogenic avian influenza viruses (HPAIV), H7 HPAIV strains have caused serious damages in poultry industries worldwide. Cases of bird-to-human transmission of H7 HPAIV have also been reported [I I]. On the outbreak of avian influenza, rapid diagnosis is critical not only for the control of HPAI but also for human health. In the present study, a rapid diagnosis kit based on immunochromatography for the detection of H7 hemagglutinin (HA) antigen of influenza A virus was developed using 2 monoclonal antibodies that recognize different epitopes on the H7 HAS. The kit detected each of the tested 15 H7 influenza virus strains and did not react with influenza A viruses of the other subtypes than H7 or other avian viral and bacterial pathogens. The kit detected H7 HA antigen in the swabs and tissue homogenates of the chickens experimentally infected with HPAIV strain A/chicken/Netherlands/2586/03 (H7N7). The results indicate that the present kit is specific and sensitive enough for the diagnosis of HPAI caused by H7 viruses, thus, recommended for the field application as a pen-site test kit.
  • Tomohisa Tanaka, Ginpei Tanoue, Masahiro Yamasaki, Ikuo Takashima, Yoshihiro Sakoda, Kenji Ochiai, Takashi Umemura
    JOURNAL OF VETERINARY MEDICAL SCIENCE 70 6 607 - 610 2008年06月 [査読有り][通常論文]
     
    Many small wild birds died in the 2005-2006 wintertime in Hokkaido. Thirteen birds were pathologically examined and it was attempted to detect West Nile and influenza viruses from their organs. Consecutive pathological changes were fresh hemorrhage and acute circulatory failure. Viral detections were negative. Selective occurrence in wintertime, literature review and the results Of pathological and virological examinations Suggested chemical deicer poisoning as the cause of wild bird death. Chicks treated orally with deicer showed acute death and their pathological changes were similar to those of the wild birds. Because the chicks showed significant elevation of plasma Na concentration, plasma electrolyte analysis of the affected wild birds might be crucial to confirm Our tentative diagnosis.
  • Ken-ichiro Kameyama, Yoshihiro Sakoda, Keita Matsuno, Asako Ito, Motoshi Tajima, Shigeyuki Nakamura, Hiroshi Kida
    MICROBIOLOGY AND IMMUNOLOGY 52 5 277 - 282 2008年05月 [査読有り][通常論文]
     
    The NS2-3 of BVDV is cleaved in cultured cells infected with cp BVDV but not in those infected with ncp BVDV when tested more than 10 hours post infection. However, it is not known whether cleavage of NS2-3 occurs in vivo. In the present study, cleavage of NS2-3 in cattle persistently infected with BVDV was investigated. All BVDV isolated from PI animals were of the ncp biotype, and NS2-3 proteins were detected in bovine fetal muscular cells infected with these viruses. On the other hand, in the leukocytes of those PI animals, NS3 proteins, products of the cleavage of NS2-3 proteins, were detected. In addition, the NS3 proteins were also detected in leukocytes artificially infected with ncp BVDV. These results reveal that the NS2-3 protein of BVDV is cleaved in leukocytes. Furthermore, NS3 proteins were detected in many tissues of PI cattle, such as lymphoid tissue, brain, thyroid, lung, and kidney. These results suggest that the NS2-3 protein of ncp BVDV cleaves in vivo.
  • Saori Sakabe, Yoshihiro Sakoda, Yoshinari Haraguchi, Norikazu Isoda, Kosuke Soda, Hiroki Takakuwa, Kazue Saijo, Akira Sawata, Katsumi Kume, Junko Hagiwara, Kotaro Tuchiya, Zhifeng Lin, Ryuichi Sakamoto, Takashi Imamura, Takashi Sasaki, Norihide Kokumai, Yoshihiro Kawaoka, Hiroshi Kida
    VACCINE 26 17 2127 - 2134 2008年04月 [査読有り][通常論文]
     
    During 2001-2004, 41 H7 influenza viruses (2 H7N1 and 39 H7N7 strains) were isolated from fecal samples of migratory ducks that flew from Siberia in the autumn of each year to Japan and Mongolia. A phylogenetic analysis of the hemagglutinin (HA) genes of the nine representative isolates revealed that they belonged to the Eurasian Lineage and the deduced amino acid sequence at the cleavage site of the HAs represented apathogenic profiles. One of the H7 isolates A/duck/Mongolia/736/02 (H7N7) was chosen from these H7 isolates for the preparation of the test vaccine. To improve the growth potential of A/duck/Mongolia/ 736/02 (H7N7) in chicken embryos, A/duck/Hokkaido/Vac-2/04 (H7N7) was generated by genetic reassortment between A/duck/Mongolia/736/02 (H7N7) as the donor of the PB2, PB1, PA, HA, NA, and NS genes and A/duck/Hokkaido/49/98 (H9N2) as that of NP and M genes. The test vaccine was prepared as follows; A/duck/Hokkaido/Vac-2/04 (H7N7) was propagated in chicken embryos and the virus in the allantoic fluid was inactivated and adjuvanted to form an oil-in-water emulsion. The test vaccine conferred immunity to chickens, completely protecting the manifestation of clinical signs against the challenge with lethal dose of H7 highly pathogenic avian influenza virus. These results indicate that influenza viruses isolated from natural reservoirs are useful for vaccine strains. (C) 2008 Elsevier Ltd. All rights reserved.
  • Makoto Nagai, Michiko Hayashi, Mika Itou, Toyoko Fukutomi, Hiroomi Akashi, Hiroshi Kida, Yoshihiro Sakoda
    VIRUS GENES 36 1 135 - 139 2008年02月 [査読有り][通常論文]
     
    A part of the nucleotide sequence of the 5' untranslated region (5'UTR) and E-rns region, and the genomic regions encoding for N-pro, Core, and E2 of So-like isolates and IS25CP/01 strain which belong to bovine viral diarrhea virus genotype 1 (BVDV-1) were determined and genetic comparisons were made with sequences of other BVDV subgenotypes. Phylogenetic analysis using the 5'UTR and N-pro revealed that So-like isolates and IS25CP/01 branched into independent phylogenetic branch. So-like isolates were clustered with Korean BVDV strains taken from DDBL/EMBL/GenBank in the 5'UTR. An additional two amino acid residues were found at the C terminal of the Core region of IS25CP/01. The similarity of amino acid sequence of E2 of So-like isolates and IS25CP/01 to the BVDV-1 reference strain NADL were 78.0-78.5 and 79.0, respectively. Cross-neutralization tests showed significant antigenic differences between So-like isolates and the others (Antigenic similarity (R) value: 2.2-8.8), and IS25CP/01 and the others (R value: 1.6-8.8). So-like viruses and IS25CP/01 differed from the thirteenth subgenotypes (1a-1m) reported by Jackova et al. (2007) and were classified as new genetic subtypes, BVDV-1n (So-like) and 1o (IS25CP/01).
  • Yasushi Itoh, Hiroichi Ozaki, Hideaki Tsuchiya, Kiyoko Okamoto, Ryuzo Torii, Yoshihiro Sakoda, Yoshihiro Kawaoka, Kazumasa Ogasawara, Hiroshi Kida
    VACCINE 26 4 562 - 572 2008年01月 [査読有り][通常論文]
     
    In order to prepare for the emergence of pandemic influenza viruses, we have established an influenza virus library that contains non-pathogenic influenza A virus strains with 135 combinations of 15 hemagglutinin and 9 neuraminidase subtypes. In this study, we developed a vaccine against H5N1 highly pathogenic avian influenza (HPAI) virus infection in humans using a virus strain selected from the library. We examined its immunogenic potency using cynomolgus macaques as a primate model. Virus antigen-specific antibodies were elicited by intranasal or subcutaneous administration of inactivated whole virus particle vaccines. After challenge with an H5N1 HPAI virus isolate obtained from a Vietnamese patient, the virus was detected only on next day following inoculation in the nasal and/or tracheal. swabs of vaccinated macaques that were asymptomatic. On the other hand, the viruses were isolated from nasal and tracheal swabs from non-vaccinated macaques until day 5 and day 7 after inoculation of the H5N1 HPAI virus, respectively. Although six non-vaccinated macaques developed a high body temperature, and two of them lost their appetite after HPAI virus infection, they recovered by the end of the 12-day observation period and did not show the severe symptoms that have been reported in human H5N1 virus infection cases. This demonstrates that the vaccine prepared with the non-pathogenic H5N1 virus from our influenza virus library conferred protective immunity against H5N1 HPAI virus infection to macaques. (C) 2007 Elsevier Ltd. All rights reserved.
  • Kosuke Soda, Yoshihiro Sakoda, Norikazu Isoda, Masahiro Kajihara, Yoshinari Haraguchi, Hitomi Shibuya, Hiromi Yoshida, Takashi Sasaki, Ryuichi Sakamoto, Kazue Saijo, Junko Hagiwara, Hiroshi Kida
    JAPANESE JOURNAL OF VETERINARY RESEARCH 55 2-3 93 - 98 2008年01月 [査読有り][通常論文]
     
    To establish vaccine strains of H5 and H7 influenza viruses, A/duck/Hokkaido/Vac-1/04 (H5N1) [Vac-1/04 (H5N1)], A/duck/Hokkaido/Vac-3/07 (H5N1) [Vac-3/07 (H5N1)], and A/duck/Hokkaido/ Vac-2/04 (H7N7) [Vac-2/04 (H7N7)] were generated from non-pathogenic avian influenza viruses isolated from migratory ducks. Vac-1/04 (H5N1) and Vac-3/07 (H5N1) were generated by genetic reassortment between H5N2 or H5N3 virus as an HA gene provider and H7N1 or H6N1 viruses as an NA gene provider. Vac-2/04 (H7N7) was a genetic reassortant obtained using H7N7 and H9 N2 viruses to give high growth character of the H9N2 virus in chicken embryonated eggs. The results of sequence analyses and experimental infections revealed that these H5N1 and H7N7 reassortant viruses were non-pathogenic in chickens and embryos, and had good growth potential in embryonated eggs. These viruses should be useful to develop vaccines against H5 and H7 highly pathogenic avian influenza viruses.
  • M. Malamo, K. Okazaki, Y. Sakoda, H. Kida
    VETERINARY RECORD 161 25 853 - 857 2007年12月 [査読有り][通常論文]
     
    Monoclonal antibodies (mAbs) against a recombinant carboxyl terminus of the 34 kDa protein of Mycobacterium paratuberculosis were produced in mice. Two of the mAbs cross-reacted with Mycobacterium avium and Mycobacterium intracellulare in both an ELISA and immunoblot. The recombinant protein also reacted with polyclonal sera produced in rabbits against all three mycobacteria, indicating the presence of cross-reactive epitopes in the protein. To determine the reactivity of cattle sera against epitopes recognised by the mAbs, competition assays between bovine sera and the mAbs were carried out. Two mAbs were significantly inhibited by sera from cattle that were naturally infected with M paratuberculosis. The results indicate that epitopes on the carboxyl terminus of the 34 kDa protein common to M paratuberculosis, M avium and M intracellulare readily induce antibody production in naturally infected cattle. These epitopes reduce the diagnostic specificity of the carboxyl terminus of the 34 kDa protein, which was originally thought to contain only M paratuberculosis-specific epitopes.
  • Jae-Ho Shin, Yoshihiro Sakoda, Jae Hoon Kim, Kenji Ochiai, Takashi Umemura
    JOURNAL OF VETERINARY MEDICAL SCIENCE 69 11 1167 - 1169 2007年11月 [査読有り][通常論文]
     
    Rabbits were immunized with inactivated influenza virus via the subarachnoidal (SA) or subcutaneous (SC) route, and the antibody titers in cerebrospinal fluid (CSF) and serum were assayed. There were no nervous signs or morphological lesions related to SA immunization. In the SC group, the antibody titer was elevated in serum, but not elevated in CSF. In the SA group, the antibody titer was significantly elevated in serum and even in CSF, and their antibody titers were much greater than in the SC group. The present results suggest that intrathecal immunization is more effective than SC immunization at inducing a protective immune response against the transneural spread of viruses.
  • Keita Matsuno, Yoshihiro Sakoda, Ken-ichiro Kameyama, Kyuzo Tamai, Asako Ito, Hiroshi Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 69 5 515 - 520 2007年05月 [査読有り][通常論文]
     
    The 475 strains of bovine viral diarrhea virus (BVDV) isolated from cattle in 12 prefectures of Japan in the last 7 years were phylo.genetically classified as BVDV-1 or BVDV-2 on the basis of the nucleotide sequence of the 5'-untransiated region. BVDV-1 strains were further subtyped as 1a (101 strains), 1b (163), 1c (128), 1j (3), and So CP/75-like (1), and all of the 79 BVDV-2 strains belonged to subtype 2a. These 2a BVDVs contain two isolates that had high nucleotide identities with those of highly pathogenic BVDV-2 strains reported in North America (Pellerin et al., 1994). However, acute infection with severe mortality like North American outbreak was not observed and most of the present BVDV-2 strains were isolated from persistently infected (PI) cattle showing mild or no clinical sign. Moreover, it was revealed that 61.5% of the 39 PI cattle with cytopathogenic BVDVs did not show typical mucosal disease and 54.6% of the 405 PI animals only with non-cytopathogenic BVDVs were apparently healthy. The present results indicate that the prevention of the infection with an appropriate vaccine and active surveillance covering healthy cattle are required for the control of BVD.
  • Oliver Bauhofer, Artur Summerfield, Yoshihiro Sakoda, Jon-Duri Tratschin, Martin A. Hofmann, Nicolas Ruggli
    JOURNAL OF VIROLOGY 81 7 3087 - 3096 2007年04月 [査読有り][通常論文]
     
    Viruses have evolved a multitude of strategies to subvert the innate immune system by interfering with components of the alpha/beta interferon (IFN-alpha/beta) induction and signaling pathway. It is well established that the pestiviruses prevent IFN-alpha/beta induction in their primary target cells, such as epitheloidal and endothelial cells, macrophages, and conventional dendritic cells, a phenotype mediated by the viral protein N-pro. Central players in the IFN-alpha/beta induction cascade are interferon regulatory factor 3 (IRF3) and IRF7. Recently, it was proposed that classical swine fever virus (CSFV), the porcine pestivirus, induced the loss of IRF3 by inhibiting the transcription of IRF3 mRNA. In the present study, we show that endogenous IRF3 and IRF3 expressed from a cytomegallovirus (CMV) promoter are depleted in the presence of CSFV by means of N-pro, while CSFV does not inhibit CMV promoter-driven protein expression. We also demonstrate that CSFV does not reduce the transcriptional activity of the IRF3 promoter and does not affect the stability of IRF3 mRNA. In fact, CSFV N-pro induces proteasomal degradation of IRF3, as demonstrated by proteasome inhibition studies. Furthermore, N-pro coprecipitates with IRF3, suggesting that the proteasomal degradation of IRF3 is induced by a direct or indirect interaction with N-pro. Finally, we show that N-pro does not downregulate IRF7 expression.
  • Kei Fujii, Chiharu Kakumoto, Mari Kobayashi, Sachiko Saito, Tatsuya Kariya, Yukiko Watanabe, Yoshihiro Sakoda, Hiroshi Kida, Masatsugu Suzuki
    JOURNAL OF VETERINARY MEDICAL SCIENCE 69 3 259 - 263 2007年03月 [査読有り][通常論文]
     
    For proper management and conservation of the Kuril harbor seal (Phoca vitulina stejnegeri) through disease control, serological analysis was performed for influenza A virus infection in free-ranging seals in Hokkaido, Japan. Serum samples were collected from seals at Nosappu (231 seals), Akkeshi (16) and Erimo (75), between 1998 and 2005, and were analyzed by ELISA. Antibodies to the influenza A virus were detected only in seals from Nosappu. The incidences were 11% (1/9), 3% (2/66), 12% (7/59) and 6% (5/77) in 1998, 2003, 2004 and 2005, respectively. These suggest sporadic infection. Because anti body-positive seals included juvenile seals in each year, the infections were considered to have been circulated since no later than the late 1990s until recent years. ELISA-positive sera were analyzed by hemagglutination inhibition (HI) tests to determine the subtypes. Antibodies to the H3 and H6 subtypes were detected in 10 and 2 sera, respectively. Two of the sera that had antibodies to the H6 subtype also had antibodies to the H3 subtype. These two seals were considered to have been infected with both the H3 and H6 subtypes. This is the first investigation to find antibodies to the H6 subtype in seals. Although the H6 subtype had been isolated only from avians, genetic analysis had suggested that the H6 subtype could become a novel mammalian pathogen. For definitive diagnosis, detection of the virus from the tissue or mucus of seals is required.
  • Stuart D. Blacksell, Naomi J. Bryant, Daniel H. Paris, Jenny A. Doust, Yoshihiro Sakoda, Nicholas P. J. Day
    CLINICAL INFECTIOUS DISEASES 44 3 391 - 401 2007年02月 [査読有り][通常論文]
     
    A review was performed to determine the evidence base for scrub typhus indirect immunofluorescence assay ( IFA) methodologies and the criteria for positive results. This review included a total of 109 publications, which comprised 123 eligible studies for analysis ( 14 publications included 2 substudies). There was considerable underreporting of the IFA methodology and seropositivity criteria used, with most studies using a defined cutoff titer rather than an increase in the titer in paired samples. The choice of positivity cutoff titer varied by country and purpose of the IFA test. This variation limits the comparability of seroprevalence rates between studies and, more seriously, raises questions about the appropriateness of the cutoffs for positive IFA results chosen for diagnosis of acute scrub typhus infection. We suggest that the diagnosis of scrub typhus using IFA should be based on a >= 4- fold increase in the titer in paired serum samples and should only be based on a single sample titer when there is an adequate local evidence base.
  • Michiko Naito, Yoshihiro Sakoda, Takayuki Kamikawa, Yoshiki Nitta, Kazuhiko Hirose, Mitsuaki Sakashita, Satoru Kurokawa, Hiroshi Kida
    MICROBIOLOGY AND IMMUNOLOGY 51 6 593 - 599 2007年 [査読有り][通常論文]
     
    Serum samples were collected from 938 pigs of 24 farms in Hokkaido, Kagoshima, and Okinawa prefectures in Japan in 2001-2005. Enzyme-linked immunosorbent assay (ELISA) was used for the detection of antibodies to LipL32 antigen which is common to Leptospira interrogans. Samples positive in ELISA were then investigated by microscopic agglutination test for the identification of causal leptospires. Antibodies specific to leptospires of serovars Copenhageni, Bratislava, Australis and Javanica were detected in serum samples of pigs from each of the three districts. In addition, antibodies to leptospires of serovars Autummalis and Thrassovi were predominantly detected in those from Kagoshima. The present study, thus, revealed that leptospires belonging to different serovars prevail in the pig population in Japan. In addition, it is the first detection of antibodies to leptospires belonging to serovars Javanica and Thrassovi in pigs in Japan.
  • Yoshimi Tsuda, Yoshihiro Sakoda, Saori Sakabe, Tsuyoshi Mochizuki, Yasuharu Namba, Hiroshi Kida
    MICROBIOLOGY AND IMMUNOLOGY 51 9 903 - 907 2007年 [査読有り][通常論文]
     
    Highly pathogenic avian influenza (HPAI) caused by the H5N1 subtype has given rise to serious damage in poultry industries in Asia. The virus has expanded its geographical range to Europe and Africa, posing a great risk to human health as well. For the control of avian influenza, a rapid diagnosis by detecting the causative virus and identifying its subtype is essential. In the present study, a rapid diagnosis kit combining immunochromatography with enzyme immunoassay which detects the H5 HA antigen of influenza A virus was developed using newly established anti-H5 HA monoclonal antibodies. The present kit specifically detected all of the H5 influenza viruses tested, and did not react with the other HA subtypes. H5 HA antigens were detected from swabs and tissue homogenates of chickens infected with HPAI virus strain A/chicken/Yamaguchi/7/04 (H5N1) from 2 days post inoculation. The kit showed enough sensitivity and specificity for the rapid diagnosis of HPAI.
  • K. Kameyama, Y. Sakoda, K. Tamai, H. Igarashi, M. Tajima, T. Mochizuki, Y. Namba, H. Kida
    JOURNAL OF VIROLOGICAL METHODS 138 1-2 140 - 146 2006年12月 [査読有り][通常論文]
     
    An immunochromatographic test was developed for rapid diagnosis of bovine viral diarrhea virus (BVDV) infections using monoclonal antibodies against the nonstructural protein, NS3, of the virus. The kit detected specifically the NS3 of various BVDV strains. Using the kit, leukocyte extracts of cattle infected persistently with BVDV were found positive while those of healthy cattle were negative. The sensitivity and specificity of this kit in compared with virus isolation were 100% and 97.2%, respectively. Furthermore, the test also gave positive results for calves infected acutely with BVDV in experimental infection. The BVDV antigen was detected in I ml of blood using a relatively simple procedure. This test kit should be useful for rapid diagnosis of BVD. (c) 2006 Elsevier B.V. All rights reserved.
  • Mumeka Malamo, Yoshihiro Sakoda, Hiroichi Ozaki, Hiroshi Kida
    JAPANESE JOURNAL OF VETERINARY RESEARCH 54 2-3 99 - 107 2006年11月 [査読有り][通常論文]
     
    To develop ELISA to detect antibodies specific to Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis), the carboxyl termini of the 34 kDa proteins of M. paratuberculosis and Mycobacterium avium subsp. avium (M. avium) were expressed in Escherichia cola expression system. Antibodies specific to M. paratuberculosis were detected with the truncated 34 kDa protein of M. paratuberculosis in ELISA after pre-absorption of serum samples with the truncated 34 kDa protein of M. avium. All the serum samples from cattle confirmed to be infected with M. paratuberculosis were positive and those from healthy cattle were negative in the present ELISA system. These results indicate that the established ELISA detects antibodies specific to M. paratuberculosis with high specificity and sensitivity and is an useful tool for the screening of Johne's disease.
  • Kei Fujii, Hiroki Sato, Chiharu Kakumoto, Mari Kobayashi, Sachiko Saito, Tatsuya Kariya, Yukiko Watanabe, Yoshihiro Sakoda, Chieko Kai, Hiroshi Kida, Masatsugu Suzuki
    JAPANESE JOURNAL OF VETERINARY RESEARCH 54 2-3 109 - 117 2006年11月 [査読有り][通常論文]
     
    Serological analysis was performed to detect morbillivirus infection in Kuril harbor seals in Hokkaido, Japan. Serum samples were collected from the seals at Nosappu (231 sera), Akkeshi (16), and Erimo (75) between 1998 and 2005. Antibodies to phocine distemper virus (PDV) were detected by ELISA in seals from Nosappu and Erimo. Antibodies to PDV were found in 56% (5/9) of the sampled seals from Nosappu in 1998, versus only 5% (3/66) for 2003, 1% (1/79) for 2004, and 1% (1/77) for 2005. These suggest epidemic caused by the virus in or before 1998. As antibody-positive seals included juvenile seals in 2003 and 2005, sporadic infections of the virus are thought to have occurred in recent years. In Erimo, antibodies to PDV were found in 50% (14/28) of sampled seals in 2004, versus only 13% (1/8) for 1999, 7 (1/15) for 2003, and 0 % (0/24) for 2005. These suggest sporadic infection by the virus before 2003 and the epizootic between after autumn in 2003, when samples of 2003 were collected, and 2004. Since antibodies to canine distemper virus (CDV) were detected in one adult seal from Nosappu in each year from 2003 to 2005, sporadic infections of the virus were suggested. There were no difference in incidence of seals with. antibodies to the viruses between males and females and between juveniles and adults.
  • N Isoda, Y Sakoda, N Kishida, GR Bai, K Matsuda, T Umemura, H Kida
    ARCHIVES OF VIROLOGY 151 7 1267 - 1279 2006年07月 [査読有り][通常論文]
     
    Outbreaks of highly pathogenic avian influenza (HPAI) have been occurring in domestic poultry in Asia since 1996. In the beginning of 2004, HPAI outbreaks were caused by H5N1 virus in two farms and a group of pet chickens in different areas of Japan. In the present study, the pathogenicity of A/chicken/Yamaguchi/7/04 (H5N1), which had been isolated from a dead chicken during the first outbreak in Japan, was assessed in chickens, quails, budgerigars, ducklings, mice, and miniature pigs by experimental infection. The virus was highly pathogenic to all the birds tested. Mice were susceptible to infection with a low mortality rate and miniature pigs were resistant to infection with the virus.
  • K Kameyama, Y Sakoda, K Tamai, M Nagai, H Akashi, H Kida
    VIRUS RESEARCH 116 1-2 78 - 84 2006年03月 [査読有り][通常論文]
     
    Cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strain KS86-1cp was isolated from a cow persistently infected with non-cytopathogenic (ncp) BVDV strain KS86-1ncp after development of mucosal disease by superinfection with cp BVDV strain Nose. cp BVDV strains 799cp and 839cp were also isolated from independent cattle that developed mucosal disease by superinfection with cpBVDV KS86-1cp. In the present Study, genetic analysis revealed that the genes of cp BVDV strains 799cp and 839cp were chimeras between the genes of the persisting ncp BVDVs and that of super infecting KS86-1cp. The genetic recombination that generates 799cp occurred between the identical points in the N-PRO gene region. whereas genetic recombination that generates 839cp Occurred between different points in the N-PRO gene region. Both 799cp and 839cp were inherited Jiv gene of KS86-1cp strain and envelope protein genes of the persisting Viruses. In addition, neutralization test disclosed that antigenicities of 799cp, 839cp, and KS86-1cp were also similar to each persisting virus. These findings indicate that exogenous cp BVDV containing insertion of Jiv gene in the 5 terminal region can induce genetic recombination with the original ncp BVDV at different points in the N-PRO gene region, and those viruses have high potential to change those antigenicities and pathogenicities by RNA recombination. (c) 2005 Elsevier B.V. All rights reserved.
  • GR Bai, Y Sakoda, AS Mweene, N Fujii, H Minakawa, H Kida
    JOURNAL OF VETERINARY MEDICAL SCIENCE 68 1 35 - 40 2006年01月 [査読有り][通常論文]
     
    To improve the sensitivity of a kit, ESPLINE (R) INFLUENZA A&B for rapid diagnosis of influenza by detecting influenza A or B virus specific nucleoproteins (NP), the ESPLINE (R) INFLUENZA A&B-N was developed by using newly established monoclonal antibodies (MAbs) to the respective NP molecule. MAbs FVA2-11 and FrB1-03 recognize the epitope on the amino acid region 59-130aa of the NP molecule of influenza A virus, and that on the region 72-191aa of the NP of influenza B virus, respectively. The new kit detected influenza A and B virus antigens with a detection limit of 10(2.0)-10(2.7) pfu/test, which is 4-1000 times higher than that of the original kit. Importantly, this kit detected each of influenza A viruses of the known hemagglutinin (HA) subtypes (H1-H15) including the H5N1 viruses recently isolated from human and avian sources in Asia. The kit also detected all of the 15 representative influenza B virus strains tested. The ESPLINE (R) INFLUENZA A&B-N is thus a rapid and highly sensitive and specific kit for the diagnosis of either influenza A or B virus infections.
  • Jae-Ho Shin, Yoshihiro Sakoda, Jae Hoon Kim, Tomohisa Tanaka, Hiroshi Kida, Takashi Kimura, Kenji Ochiai, Takashi Umemura
    MICROBIOLOGY AND IMMUNOLOGY 50 10 823 - 830 2006年 [査読有り][通常論文]
     
    To evaluate the efficacy of intracerebral (IQ immunization, mice were immunized with formalin-inactivated pseudorabies virus (PRV) by either subcutaneous (SQ or IC injection, and then 10(6) plaque-forming units of PRV were introduced into the hindleg of the immunized or non-immunized mice by intramuscular injection. The antibody titer in serum was elevated and boosted by additional immunization via both the SC and IC routes, but was higher after IC immunization. Intracerebrally immunized mice were completely protected from mortality and neurological signs, whereas all the non-immunized and 80% of the subcutaneously immunized mice died after developing neurological signs. In mouse models, IC immunization is more effective at inducing a protective immune response against the transneural spread of PRV than SC immunization.
  • H Kida, Y Sakoda
    OIE/FAO International Scientific Conference on Avian Influenza 124 69 - 72 2006年 [査読有り][通常論文]
     
    To prepare for the emergence of pandemic influenza in birds and mammals including humans, we have carried out global surveillance of avian influenza. Influenza A viruses of 48 combinations of 15 HA and 9 NA subtypes out of 135 theoretical combinations have been isolated from faecal samples of ducks in Alaska, Siberia, Mongolia, Taiwan, China and Japan. So far, viruses of 73 other combinations have been generated by genetic reassortment in chicken embryos. Thus, avian influenza viruses of 121 combinations of HA and NA subtypes have been stocked for use in vaccine and diagnosis. Their pathogenicity, antigenicity, genetic information, and yield in chicken embryo have been analysed and registered in the database.
  • Jae-Ho Shin, Yoshihiro Sakoda, Hoon Kim Jae, Tomohisa Tanaka, Hiroshi Kida, Takashi Kimura, Kenji Ochiai, Takashi Umemura
    Microbiology and Immunology 50 10 823 - 830 2006年 [査読有り][通常論文]
     
    To evaluate the efficacy of intracerebral (IC) immunization, mice were immunized with formalin-inactivated pseudorabies virus (PRV) by either subcutaneous (SC) or IC injection, and then 106 plaque-forming units of PRV were introduced into the hindleg of the immunized or non-immunized mice by intramuscular injection. The antibody titer in serum was elevated and boosted by additional immunization via both the SC and IC routes, but was higher after IC immunization. Intracerebrally immunized mice were completely protected from mortality and neurological signs, whereas all the non-immunized and 80% of the subcutaneously immunized mice died after developing neurological signs. In mouse models, IC immunization is more effective at inducing a protective immune response against the transneural spread of PRV than SC immunization.
  • S Takeda, A Sbagyo, Y Sakoda, A Ishii, M Sawamura, K Sueoka, H Kida, K Mukasa, K Matsumoto
    BIOSENSORS & BIOELECTRONICS 21 1 201 - 205 2005年07月 [査読有り][通常論文]
     
    Carbon nanotube sensors detected anti-hemagglutinin binding to immobilized hemagglutinins. An ultra-sensitive detection method for antibodies or antigens in serum is required. Hemagglutinins were immobilized on the reverse side of a carbon nanotube, thereby producing a source and a drain. Electrode pads covered each edge of the nanotube. The 1-V curves between the source and the drain were measured after incubation of anti-hemagglutinins with immobilized hemagglutinins in a buffered solution on the reverse side of the nanotube. The sensitivity of the CNT sensor was higher than that of an ELISA system. This method constitutes a new tool to analyze interaction among biomolecules on a substrate. (c) 2004 Elsevier B.V. All rights reserved.
  • N Kishida, Y Sakoda, N Isoda, K Matsuda, M Eto, Y Sunaga, T Umemura, H Kida
    ARCHIVES OF VIROLOGY 150 7 1383 - 1392 2005年07月 [査読有り][通常論文]
     
    Four H5N1 highly pathogenic avian influenza (HPAI) viruses and an avirulent reassortant H5N1 virus were tested for their pathogenicity in domestic ducks. A/chicken/Yamaguchi/7/04 (H5N1) (Ck/Yamaguchi/04) isolated from a dead bird during the HPAI outbreak in Japan and A/duck/Yokohama/aq-10/03 (H5N1) (Dk/Yokohama/03) isolated from duck meat at a quarantine inspection for importation from China replicated in multiple organs including the brain of ducks. The ducks infected with Ck/Yamaguchi/04 did not show any clinical signs, while those infected with Dk/Yokohama/03 showed neurological signs. The ducks infected either with A/Hong Kong/483/97 (H5N1) orA/tern/SouthAfrica/61 (H5N3), or with an avirulent H5N1 reassortant, did not show any clinical signs. Virus-specific antibodies were detected in the sera of the ducks infected with each of the five strains tested, indicating that all of the viral strains infected and replicated in the birds. Dk/Yokohama/03 grew in multiple organs more rapidly than did Ck/Yamaguchi/04. Considerable titers of virus were detected in the brain of the ducks infected with Dk/Yokohama/03 and these birds showed neurological signs. The present results demonstrate that the pathogenicity of influenza viruses for ducks does not correlate with that for chickens and that replication of the virus in the brain is critical for ducks to show neurological signs.
  • N Odontsetseg, Y Sakoda, H Kida
    VETERINARY RECORD 157 4 120 - 121 2005年07月 [査読有り][通常論文]
  • K Matsuda, T Shibata, Y Sakoda, H Kida, T Kimura, K Ochiai, T Umemura
    JOURNAL OF GENERAL VIROLOGY 86 4 1131 - 1139 2005年04月 [査読有り][通常論文]
     
    Neural involvement following infections of influenza viruses can be serious. The neural transport of influenza viruses from the periphery to the central nervous system has been indicated by using mouse models. However, no direct evidence for neuronal infection has been obtained in vitro and the mechanisms of neural transmission of influenza viruses have not been reported. In this study, the transneural transmission of a neurotropic influenza A virus was examined using compartmentalized cultures of neurons from mouse dorsal root ganglia, and the results were compared with those obtained using the pseudorabies virus, a virus with well-established neurotransmission. Both viruses reached the cell bodies of the neurons via the axons. This is the first report on axonal transport of influenza A virus in vitro. In addition, the role of the cytoskeleton (microtubules, microfilaments and intermediate filaments) in the neural transmission of influenza virus was investigated by conducting cytoskeletal perturbation experiments. The results indicated that the transport of avian influenza A virus in the neurons was independent of microtubule integrity but was dependent on the integrity of intermediate filaments, whereas pseudorabies virus needed both for neural spread.
  • The vagus nerve is one route of transneural invasion for intranasally inoculated influenza A virus in mice
    Matsuda K, Shibata T, Sakoda Y, Kida H, Kimura T, Ochiai K, Umemura T
    Journal of General Virology 86 1131 - 1139 2005年04月 [査読有り][通常論文]
  • T Inoue, S Alexandersen, AT Clark, C Murphy, M Quan, SM Reid, Y Sakoda, HL Johns, GJ Belsham
    JOURNAL OF VIROLOGY 79 1 428 - 440 2005年01月 [査読有り][通常論文]
     
    A major virulence determinant of swine vesicular disease virus (SVDV), an Enterovirus that causes an acute vesicular disease, has been mapped to residue 20 of the 2A protease. The SVDV 2A protease cleaves the ID-2A junction in the viral polyprotein, induces cleavage of translation initiation factor eIF4GI, and stimulates the activity of enterovirus internal ribosome entry sites (IRESs). The 2A protease from an attenuated strain of SVDV (Ile at residue 20) is significantly defective at inducing cleavage of eIF4GI and the activation of IRES-dependent translation compared to the 2A protease from a pathogenic strain (J1/73, Arg at residue 20), but the two proteases have similar ID-2A cleavage activities (Y. Sakoda, N. Ross-Smith, T. Inoue, and G. J. Belsham, J. Virol. 75:10643-10650, 2001). Residue 20 has now been modified to every possible amino acid, and the activities of each mutant 2A protease has been analyzed. Selected mutants were reconstructed into full-length SVDV cDNA, and viruses were rescued. The rate of virus growth in cultured swine kidney cells reflected the efficiency of 2A protease activity. In experimentally infected pigs, all four of the mutant viruses tested displayed much-reduced virulence compared to the J1/73 virus but a significant, albeit reduced, level of viral replication and excretion was detected. Direct sequencing of cDNA derived from samples taken early and late in infection indicated that a gradual selection-reversion to a more efficient protease occurred. The data indicated that extensive sequence change and selection may introduce a severe bottleneck in virus replication, leading to a decreased viral load and reduced or no clinical disease.
  • N Odontsetseg, Y Sakoda, H Kida
    MICROBIOLOGY AND IMMUNOLOGY 49 9 865 - 869 2005年 [査読有り][通常論文]
     
    Serum samples were collected randomly from Mongol breed cattle in three geographically distinct provinces of Mongolia. Antibodies specific to Leptospira interrogans serovar Hardjo were detected by microscopic agglutination test (MAT) at titres of 100 or more in 80.4% (86/107) of the samples from Dornod Province, but in only 28.9% (13/45) in Arkhangai and 23.5% (12/51) in Khuvsgul Provinces, respectively. Treatment of 9 serum samples from Dornod, positive to serovar Hardjo in MAT and negative in the homologous immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), with 2-mercaptoethanol (2-ME) indicated that those animals were recently infected.
  • GR Bai, Y Sakoda, AS Mweene, N Kishida, T Yamada, H Minakawa, H Kida
    MICROBIOLOGY AND IMMUNOLOGY 49 12 1063 - 1067 2005年 [査読有り][通常論文]
     
    The ESPLINE(R) INFLUENZA A&B-N kit was evaluated for its applicability to the rapid diagnosis of influenza in chickens and pigs. The kit specifically detected viral antigens in tracheal swabs and tissue homogenates of the trachea, liver, spleen, and colon of chickens inoculated with a highly pathogenic avian influenza virus strain, A/chicken/Yamaguchi/7/04 (H5N1), at 48 hr post-inoculation (p.i.) as well as in the tracheal and cloacal swabs and tissue homogenates of dead chickens. For those infected with a low pathogenic strain, A/chicken/aq-Y-55/01 (H9N2), antigens were detected only in the samples from tracheal swabs and organs 1-4 days p.i. The kit also detected viral antigens in the nasal swabs of miniature pigs infected with swine and avian influenza viruses. The kit was found to be sensitive and specific enough for the rapid diagnosis of infections of influenza A virus in chickens and pigs.
  • N Kishida, Y Sakoda, M Eto, Y Sunaga, H Kida
    ARCHIVES OF VIROLOGY 149 11 2095 - 2104 2004年11月 [査読有り][通常論文]
     
    H9N2 influenza viruses are frequently isolated from chicken meat and bone marrow imported from China to Japan since 2001. These isolates were experimentally inoculated into specific pathogen-free chickens intranasally. Viruses were recovered from the meat and bone marrow of birds showing no overt signs. On the other hand, chickens co-infected with H9N2 virus and either Staphylococcus aureus or Haemophilus paragallinarum showed clinical signs severer than those shown by birds infected only with the virus alone or each of the bacteria alone. In addition, H9N2 viruses were more efficiently recovered from the chickens co-infected with S. aureus or H. paragallinarum than those from the birds infected with only the virus. The present results indicate that co-infection of H9N2 influenza virus with S. aureus or H. paragallinarum enhances the replication of the virus in chickens, resulting in exacerbation of the H9N2 virus infection.
  • M Nagai, M Hayashi, S Sugita, Y Sakoda, M Mori, T Murakami, T Ozawa, N Yamada, H Akashi
    VIRUS RESEARCH 99 2 103 - 113 2004年02月 [査読有り][通常論文]
     
    Phylogenetic analysis of the five different regions (5' non-coding region (5'NCR), N-pro, E2, NS3 and NS5B-3'NCR) of 48 Japanese and reported bovine viral diarrhea virus (BVDV) genomes was performed. Japanese BVDVs were segregated into BVDV1 subdivided into six subgroups and BVDV2. One isolate, So CP/75, isolated in 1975 and previously proposed as subgroup 1e according to its 5'NCR sequence, was quite unique and formed an independent lineage in the tree of any region. Another isolate, 190CP, obtained from an experimental mucosal disease case was classified as subgroup 1e, defined by Becher et al. in the 5'NCR, N-pro and E2 regions, whereas it was classified as subgroup la in the NS5B-3'NCR region. The genomic sequences of the American isolates ILLC and ILLNC obtained from the GenBank database were assigned into subgroup 1b in the 5'NCR, N-pro, E2 and NS5B-3'NCR regions, whereas they were assigned into subgroup la in the NS3 region, suggesting that recombination between the virus strains classified into different subgroups had occurred in an animal. These findings suggest that phylogenetic analysis of several genetic regions is useful for the further characterization of field BVDV isolates. (C) 2003 Elsevier B.V. All rights reserved.
  • H Aoki, Y Sakoda, S Nakamura, S Suzuki, A Fukusho
    JOURNAL OF VETERINARY MEDICAL SCIENCE 66 2 161 - 167 2004年02月 [査読有り][通常論文]
     
    Pestiviruses can be distinguished as two biotypes, cytopathogenic (cp) and noncytopathogenic (noncp), by the morphological changes that they induce during growth in cultured cells. In this study, the cp phenotype of several classical swine fever viruses (CSFV) was evaluated by the detections of the nonstructural proteins NS2-3 and NS3 using immunoprecipitation and Western blotting in different porcine cell lines. Most CSFVs that showed the exaltation of Newcastle disease virus (END) phenomenon (END+ viruses) did not induce cytopathic effect (CPE)in any cell line, and detections of NS2-3 and NS3 showed a strong signal for NS2-3 in the END+ virus-infected cells. However, clear CPE was observed in serum-free cultured cells (FS-L3 and CPK-NS) infected with viruses that induce intrinsic interference but did not show the END phenomenon (END- viruses), and signal of NS3 was strongly detected than that of NS2-3 in these cells at 72 hr after infection. As the results of the analysis of FS-L3 cells infected with ALD (END+ virus) and ALD-END- virus (END- virus) at several incubations, the signal of NS3 detected was strengthened with CPE that become evident progressively. These results suggest that CPE is associated with the accumulation of NS3, which is promoted in serum-free cell lines infected with END- viruses. Thus, indicating there is a close relationship between CPE and the quantity of NS3 produced in END- CSFV infection.
  • Y Sakoda, T Ito, K Okazaki, A Takada, Y Ito, K Tamai, M Okamatsu, KF Shortridge, RG Webster, H Kida
    OPTIONS FOR THE CONTROL OF INFLUENZA V 1263 674 - 677 2004年 [査読有り][通常論文]
     
    For the prediction of future influenza pandemics, global surveillance of avian influenza has been continuing since 1991 and carried out in Russia, Mongolia, China and Japan from 2000 to 2003. Influenza virus isolates of 50 combinations of HA and NA subtypes have been identified and 3 strains selected from each of those are stocked. In addition, 47 other combinations have been generated by standard genetic reassortment procedure in the laboratory. Since we have already shown that influenza viruses have been fully adapted to ducks and cause no disease signs and are in evolutionary stasis in their natural reservoirs, virus isolates from ducks are ideal as vaccine strains. Thus, influenza viruses of 97 combinations of HA and NA subtypes are now available as vaccine strain candidates against emerging pandemic influenza in humans, domestic animals and poultry. (C) 2003 Elsevier B.V. All rights reserved.
  • JH Liu, K Okazaki, H Ozaki, Y Sakoda, QM Wu, FY Chen, H Kida
    AVIAN PATHOLOGY 32 5 551 - 560 2003年10月 [査読有り][通常論文]
     
    Ten H9N2 influenza virus strains isolated from diseased chickens in different farms in China during 1995 to 1999 were antigenically and genetically characterized. The haemagglutinins of the isolates were not related to those of A/quail/ Hong Kong/G1/97 ( H9N2) (Qa/HK/G1/97), but were closely related to that of A/chicken/ Hong Kong/G9/97 ( H9N2) (Ck/HK/G9/97). The neuraminidase of these isolates had a deletion of three amino acid residues at positions 63 to 65 as compared with those of Ck/HK/G9/97, while that of Qa/HK/G1/97 lacked two amino acids at positions 38 and 39. The PB2 genes of the isolates were not related to those of Qa/HK/G1/ 97 or Ck/HK/G9/97, but showed some relationship to that of A/duck/Hong Kong/Y439/97 ( H9N2) (Dk/HK/Y439/ 97). The PB1 genes of the isolates were not related to those of the three representative strains. The PA, NP, M, and NS genes of the isolates belonged to the same lineage as those of Ck/HK/G9/97, and were distinct from those of Qa/HK/G1/ 97 and Dk/HK/Y439/97. The present results indicate that H9N2 influenza viruses prevalent in chicken populations in China belong genetically to one lineage and are distinct from Qa/HK/G1/ 97, presumed to be the donor of the internal protein genes of the highly pathogenic H5N1 influenza virus in Hong Kong in 1997.
  • M Nagai, Y Sakoda, M Mori, M Hayashi, H Kida, H Akashi
    JOURNAL OF GENERAL VIROLOGY 84 2 447 - 452 2003年02月 [査読有り][通常論文]
     
    The cytopathogenic bovine viral diarrhoea virus (cp BVDV) strain KS86-1 cp was isolated from a calf persistently infected with the noncytopathogenic (ncp) strain KS86-1 ncp after it was exposed to cp BVDV strain Nose and developed mucosal disease (MD). Molecular analysis revealed that an insertion of a cellular gene and a duplication of the viral RNA encoding the nucleocapsid protein C and part of N-pro had occurred in the C coding region of the Nose and KS86-1 cp genomes. The inserted cellular gene was closely related to the cINS sequence. Remarkably, the 5' upstream region from the insertion of KS86-1 cp had high sequence identity to that of Nose, but differed from that of KS86-1 ncp. In contrast, the region downstream from the insertion of KS86-1 cp showed high identity to KS86-1 ncp, but not to Nose. These data reveal that KS86-1 cp is a chimeric virus generated by homologous RNA recombination in a calf with MD.
  • Y Sakoda, N Ross-Smith, T Inoue, GJ Belsham
    JOURNAL OF VIROLOGY 75 22 10643 - 10650 2001年11月 [査読有り][通常論文]
     
    Virulent and avirulent strains of swine vesicular disease virus (SVDV), a picornavirus, have been characterized previously. The major determinants for attenuation have been mapped to specific residues in the 1D-2A-coding region. The properties of the 2A proteases from the virulent and avirulent strains of SVDV have now been examined. Both proteases efficiently cleaved the 1D/2A junction in vitro and in vivo. However, the 2A protease of the avirulent strain of SVDV was much less effective than the virulent-virus 2A protease at inducing cleavage of translation initiation factor eIF4GI within transfected cells. Hence the virulent-virus 2A protease is much more effective at inhibiting cap-dependent protein synthesis. Furthermore, the virulent-virus 2A protease strongly stimulated the internal ribosome entry sites (IRESs) from coxsackievirus B4 and from SVDV, while the avirulent-virus 2A protease was significantly less active in these assays. Thus, the different properties of the 2A proteases from the virulent and avirulent strains of SVDV in regulating protein synthesis initiation reflect the distinct pathogenic properties of the viruses from which they are derived. A single amino acid substitution, adjacent to His21 of the catalytic triad, is sufficient to confer the characteristics of the virulent-strain 2A protease on the avirulent-strain protease. It is concluded that the efficiency of picornavirus protein synthesis, controlled directly by the IRES or indirectly by the 2A protease, can determine virus virulence.
  • M Nagai, T Ito, S Sugita, A Genno, K Takeuchi, T Ozawa, Y Sakoda, T Nishimori, K Takamura, H Akashi
    ARCHIVES OF VIROLOGY 146 4 685 - 696 2001年 [査読有り][通常論文]
     
    Genomic properties of 62 field isolates of bovine viral diarrhea virus (BVDV) collected fi-om 1974 to 1999 in Japan were investigated. The 5' untranslated region (UTR) was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) and the 244 to 247 base nucleotide sequences were determined. Serological properties were also characterized by the cross-neutralization test using antisera against the representative strain of the classified genotype. Using phylogenetic tree analysis, BVDV 1 was subdivided into two major clusters, BVDV-1a (29 isolates) and BVDV-1b (27 isolates). In group 1a, 3 differed from the other viruses, and were classified in a branch assigned as 1a'. However, 4 isolates (So CP/75, 190 CP, 190 NCP and KS86-1-NCP) could not be assigned to group 1a or 1b. In comparison with the published sequence data, KS86-1-NCP, 190 CP and 190 NCP were similar to the Southern Africa isolates that have recently been proposed as BVDV 1c. The 5' UTR sequence of So CP/75 was unique among those of BVDV 1, suggesting that the isolate should be classified into a new genotype. Only 2 out of 62 isolates collected in 1989 and 1990 were identified as BVDV 2. The results of the cross-neutralization test strongly supported these data, suggesting a close correlation between the 5' UTR sequence and the antigenicity of BVDV.
  • H Aoki, Y Sakoda, K Jukuroki, A Takada, H Kida, A Fukusho
    VETERINARY MICROBIOLOGY 68 3-4 197 - 207 1999年08月 [査読有り][通常論文]
     
    The glycoprotein gB of pseudorabies virus (PrV) was expressed in various mammalian cells by a recombinant baculovirus carrying the PrV gB gene under the control of the CAG promoter. When the recombinant baculovirus was inoculated into the stable porcine kidney cell line CPK, expression of PrV gB was detected by immunofluorescent antibody analysis and a 155 kDa of protein, which has the same molecular mass as the native PrV gB, was detected by Western blotting. High levels of expression of PrV gB were observed in BHK-21, HmLu-1 and SK-K cell Lines. Furthermore, anti-PrV gB-specific antibodies against PrV gB protein were detected by the enzyme-linked immunosorbent assay in mice inoculated the recombinant baculovirus. The recombinant baculovirus containing the PrV glycoprotein gB gene under the CAG promoter could be a candidate for a pseudorabies vaccine. (C) 1999 Elsevier Science B.V. All rights reserved.
  • Yoshihiro Sakoda, Shin-Ichi Ozawa, Sudarat Damrongwatanapokin, Mitsuo Sato, Kiyoyasu Ishikawa, Akio Fukusho
    Veterinary Microbiology 65 1 75 - 86 1999年02月23日 [査読有り][通常論文]
     
    The genetic variability of porcine and ruminant pestiviruses was studied by comparative nucleotide sequence analysis of 73 isolates (42 porcine and 31 ruminant), including 65 Japanese isolates (35 porcine and 30 ruminant). The 5'-untranslated region (UTR) amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) was determined by direct sequencing and phylogenetic analysis was performed from the nucleotide sequence data. Most porcine isolates were divided into two major subgroups, classical swine fever virus (CSFV) subgroup 1 (CSFV-1, represented by Brecia strain) and subgroup 2 (CSFV-2, represented by Alfort strain). However, the Japanese Kanagawa/74, Okinawa/86, Okinawa/86-2 and Thai CBR/93 strains were the most distinct variants and these were assigned to another new disparate subgroup, CSFV-3 (represented by p97 strain). Most ruminant isolates were classified as the bovine viral diarrhoea virus (BVDV) genotype-I (BVDV-I) and subdivided into two subgroups, BVDV-Ia (represented by the NADL strain) and Ib (represented by the Osloss strain). Two bovine isolates (MS-1 and SY-89) and a contaminating strain (V/FLL) from an ovine cell line were classified as BVDV genotype-II (BVDV-II) on genetic characteristics. These data suggested that the detection and phylogenetic analysis of 5'-UTRs are useful for the rapid characterization of field isolates.
  • Y Sakoda, M Hikawa, T Tamura, A Fukusho
    JOURNAL OF VIROLOGICAL METHODS 75 1 59 - 68 1998年11月 [査読有り][通常論文]
     
    A stable porcine kidney cell line, CPK-NS, was established and maintained in serum-free culture. A cytopathic effect (CPE) was observed clearly in CPK-NS cells infected with some classical swine fever virus (CSFV) strains which did not show the exaltation of Newcastle disease virus (END) phenomenon. Chromosome condensation and DNA fragmentation, a marker for apoptosis, were detected in cells infected with END phenomenon-negative CSFV strains. By using the CPE induced by infection with an END phenomenon-negative CSFV strain in CPK-NS cells, assays of CSFV were established. The virus titer determined in CPK-NS cells shows a high correlation with the usual peroxidase-linked assay, dome disappearance method and END method. Furthermore, the antibody titer by neutralizing test with CPK-NS cells also correlated with that measured by the usual neutralizing peroxidase-linked assay and dome disappearance method. These stable CPK-NS cells have the great advantage that a clear CPE was caused by infection with END phenomenon-negative CSFV strains and bovine serum is not necessary for cell culture and virus assays. (C) 1998 Elsevier Science B.V. All rights reserved.
  • Y Sakoda, A Fukusho
    IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-ANIMAL 34 1 53 - 57 1998年01月 [査読有り][通常論文]
     
    A stable porcine kidney epithelial cell line, FS-L3, was established and maintained in Eagle's minimum essential medium containing 0.295% tryptose phosphate broth, 0.5% Bacto Peptone, and 10 mM N, N-Bis (2-hydroxyethyl)-2-aminoethanesulfonic acid without any serum. The mode of chromosomes is 37 to 38. The FS-L3 cells formed fluid-filled, multicellular, three-dimensional domes on a single monolayer. The number of domes increased markedly after further cultivation. The origin of this cell line was confirmed as porcine by hybridization using PRE-I, which can be detected as a specific sequence in the porcine genome. It was also found that FS-L3 cells were free from possible adventitious viruses and mycoplasmas.
  • E ONO, Y SAKODA, S TAHARAGUCHI, S WATANABE, N TONOMURA, H KIDA, Y SHIMIZU
    VIROLOGY 210 1 128 - 140 1995年06月 [査読有り][通常論文]
     
    A chimeric gene encoding a fusion protein consisting of the DNA-binding domain of the immediate-early (IE) protein of pseudorabies virus (PRV) and a tail-truncated Vmw65 of herpes simplex virus I, lacking the transcription activation domain, was constructed. The chimeric gene product inhibited transcription from the PRV IE promoter in a transient expression assay. A HeLa cell line stably transformed with the chimeric gene showed remarkable resistance to PRV infection. In the transformed cells infected with PRV, transcription of the PRV IE gene was repressed, indicating that the resistance of the cells to PRV infection was due to interference with IE gene transcription by the fusion protein. (C) 1995 Academic Press, Inc.

その他活動・業績

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    豚コレラウイルスはフラビウイルス科ペスチウイルス属のウイルスの1つである。このウイルスによるブタとイノシシの感染症である豚コレラは、口蹄疫やアフリカ豚コレラと同様に養豚において最も恐れられているブタの感染症である。2018年9月に国内としては26年ぶりに発生が報告され、56事例の感染が報告されている。感染拡大の要因は野生イノシシにおけるウイルスの蔓延であるが、野生動物における感染症のコントロールには時間がかかる。よって養豚場における衛生対策の徹底を継続することが必要である。本稿では、豚コレラウイルスを含むペスチウイルス属のウイルスに関する最新情報と日本における豚コレラの対策について紹介する。(著者抄録)
  • 迫田 義博 臨床と微生物 46 (6) 703 -708 2019年11月 [査読無し][通常論文]
     
    豚コレラは最も恐れられているブタのウイルス感染症の1つである。2018年9月に国内としては26年ぶりに発生が報告された。野生イノシシにおけるウイルスの蔓延阻止が本病撲滅の鍵であるが、野生動物における感染症のコントロールには時間がかかるので、養豚場における衛生対策の徹底を継続することが必要である。(著者抄録)
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    哲翁 まどか, 松野 啓太, 田村 友和, 福原 崇介, 松浦 善治, 岡松 正敏, 迫田 義博 日本獣医学会学術集会講演要旨集 162回 393 -393 2019年08月 [査読無し][通常論文]
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    柴田 明弘, 原田 理恵子, 岡松 正敏, 松野 啓太, 有田 知子, 鈴木 康司, 白倉 雅之, 小田切 孝人, 竹前 喜洋, 内田 裕子, 西藤 岳彦, 迫田 義博, 尾坂 優之 日本獣医学会学術集会講演要旨集 162回 395 -395 2019年08月 [査読無し][通常論文]
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    迫田 義博 臨床獣医 37 (8) 105 -109 2019年07月 [査読無し][通常論文]
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  • 迫田義博, 迫田義博 家畜衛生学雑誌 44 (2) 61‐64 2018年12月14日 [査読無し][通常論文]
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    Twabela Augustin, Tshilenge George, Nguyen Thanh-Lam, 松野 啓太, Monne Isabella, Zecchin Bianca, 岡松 正敏, 迫田 義博 日本獣医学会学術集会講演要旨集 161回 356 -356 2018年08月 [査読無し][通常論文]
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    Nguyen Thanh-Lam, Stevenson Mark, Firestone Simon, Sims Les, Chu Huy, Nguyen Long, Nguyen Tien, 磯田 典和, 松野 啓太, 岡松 正敏, 喜田 宏, 迫田 義博 日本獣医学会学術集会講演要旨集 161回 357 -357 2018年08月 [査読無し][通常論文]
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    Enkhbold Bazarragchaa, 岡松 正敏, Ulaankhuu Ankhanbaatar, 松野 啓太, 喜田 宏, 新井 宏育, 迫田 義博 日本獣医学会学術集会講演要旨集 161回 357 -357 2018年08月 [査読無し][通常論文]
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  • 岡松正敏, 迫田義博 小児科臨床 70 2318‐2322 2017年12月20日 [査読無し][通常論文]
  • H5N1高病原性鳥インフルエンザウイルスのシアル酸非依存的な細胞侵入経路の解析
    梶原 直樹, 野村 奈美子, 宇梶 麻紗子, 貞任 大地, 山本 直樹, 小原 道法, 安井 文彦, 迫田 義博, 喜田 宏, 芝崎 太 生命科学系学会合同年次大会 2017年度 [2P -0957] 2017年12月 [査読無し][通常論文]
  • Takara Hajake, Dacquin Muhandwa Kasumba, Haruka Oda, Keita Matsuno, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroki Kato, Takashi Fujita CYTOKINE 100 27 -27 2017年12月 [査読無し][通常論文]
  • H5N1高病原性鳥インフルエンザウイルスのシアル酸非依存的な細胞侵入経路の解析
    梶原 直樹, 野村 奈美子, 宇梶 麻紗子, 貞任 大地, 山本 直樹, 小原 道法, 安井 文彦, 迫田 義博, 喜田 宏, 芝崎 太 生命科学系学会合同年次大会 2017年度 [2P -0957] 2017年12月 [査読無し][通常論文]
  • 【グローバル化・温暖化と感染症対策】 新興・再興感染症 H7N9鳥インフルエンザ
    岡松 正敏, 迫田 義博 小児科臨床 70 (増刊) 2318 -2322 2017年12月 [査読無し][通常論文]
  • 迫田義博, 迫田義博, 喜田宏, 喜田宏 感染症 47 (6) 189‐199 -199 2017年11月20日 [査読無し][通常論文]
     
    H5N1亜型の高病原性鳥インフルエンザウイルスが1996年に中国で出現し、1997年には鳥からヒトへの感染が初めて報告され、世界的な関心が高まった。それから20年経過したが、ニワトリからアヒル農場での対策が不徹底な諸外国の影響を受け、ウイルスはいまだにこれらの国々の農場で流行を繰り返している。ウイルスは環境中に漏れ出し、渡り鳥に感染することで大陸を越えて運ばれる事態となり、日本もその被害国の1つである。H5ウイルスはヒトからヒトへの感染は報告されていないが、鳥からヒトに直接感染し、現在も死亡者が報告されている。初発生以降、中国や東南アジアでニワトリやアヒルに対しワクチンが使用されているため、ワクチン接種群での見えない感染(不顕性感染)が続き、同時に抗原変異株が次々と出現した。H5亜型高病原性鳥インフルエンザウイルスの進化は、20年間途切れることなく、ワクチン接種下でウイルスがニワトリやアヒルの間で受け継がれたことが最大の要因である。このウイルスの抗原性と遺伝子の進化(変異)は、すべての鳥インフルエンザ対策をさらに難しくさせている。このH5亜型に加え、H7亜型高病原性鳥インフルエンザウイルスが中国で新たに出現し、ヒトへの感染も報告されている。ニワトリやアヒル、すなわち家禽における鳥インフルエンザ対策を徹底し、環境中に漏れ出るウイルスをなくすこと以外、動物と人の健康を守る手段はない。(著者抄録)
  • 市川正孝, 三田村敬子, 安倍隆, 岡田隆滋, 岡田隆文, 後藤泰浩, 迫田義博, 佐藤勇, 時田章史, 豊田茂, 中尾歩, 藤枝俊之, 松井忠孝, 松永貞一, 山崎雅彦, QIAN Yuan, MAI Le, 齋藤玲子 医学と薬学 74 (10) 1299‐1310 -1310 2017年09月27日 [査読無し][通常論文]
     
    新しいインフルエンザ抗原迅速診断キット「クイックナビ-Flu2」(デンカ生研株式会社)の性能評価を行った。本品は着色ラテックス粒子を用いたイムノクロマト法を原理とした試薬であり、最終陰性判定時間が5分と従来品に比べ短縮され、かつラインが見やすくなったことが特徴である。基礎的検討では主な呼吸器感染症の原因ウイルスおよび細菌との交差反応は認められず、ヒトおよび動物由来のA型インフルエンザウイルスとの反応性も確認した。臨床性能試験(鼻腔拭い液n=248、鼻腔吸引液n=518、咽頭拭い液n=685)では、ウイルス分離培養を基準とした本品の感度はA型:94.8〜97.0%、B型:90.8〜97.8%、特異度はA型:98.4〜99.0%、B型:94.7〜98.3%で、全体一致率はいずれの検体種においても90%以上と良好な結果であった。また陽性となった症例の約90%が2分以内に判定が可能であり、5分という最終陰性判定時間を考慮するとインフルエンザ流行期の診療効率の改善に有用な診断キットであると考えられた。(著者抄録)
  • 増田恒幸, 黒田萌黄, 岩尾健, 池本千恵美, 小谷道子, 増田康充, 亀山健一郎, 迫田義博 日本獣医師会雑誌 70 (9) 575‐579 -579 2017年09月20日 [査読無し][通常論文]
     
    鳥取県では2012年以降、牛ウイルス性下痢ウイルス(BVDV)感染症清浄化対策を実施しており、多数の持続感染(PI)牛を摘発している。2016年1月から10月にかけてBVDV-1のPI牛が3農場で6頭摘発された。疫学調査の結果、6頭の母牛はほぼ同じ期間に県外の同一育成牧場へ預託されていたことが判明した。6頭中5頭から分離されたBVDVのE2遺伝子領域の分子系統樹解析では、5株はすべてBVDV-1cに分類され、株間の相同性は99.6〜99.9%であった。このことから、PI牛の母牛は預託期間中にBVDV-1cに感染し、帰還後にPI牛を産出したと推察された。県外預託牛由来PI牛によるBVDVの侵入パターンが示されたため、BVDV感染症清浄化には地域単位の対策だけでなく、国主導による全国的な対策が必要と考えられた。(著者抄録)
  • 増田 恒幸, 黒田 萌黄, 岩尾 健, 池本 千恵美, 小谷 道子, 増田 康充, 亀山 健一郎, 迫田 義博 日本獣医師会雑誌 70 (9) 575 -579 2017年09月 [査読無し][通常論文]
     
    鳥取県では2012年以降、牛ウイルス性下痢ウイルス(BVDV)感染症清浄化対策を実施しており、多数の持続感染(PI)牛を摘発している。2016年1月から10月にかけてBVDV-1のPI牛が3農場で6頭摘発された。疫学調査の結果、6頭の母牛はほぼ同じ期間に県外の同一育成牧場へ預託されていたことが判明した。6頭中5頭から分離されたBVDVのE2遺伝子領域の分子系統樹解析では、5株はすべてBVDV-1cに分類され、株間の相同性は99.6〜99.9%であった。このことから、PI牛の母牛は預託期間中にBVDV-1cに感染し、帰還後にPI牛を産出したと推察された。県外預託牛由来PI牛によるBVDVの侵入パターンが示されたため、BVDV感染症清浄化には地域単位の対策だけでなく、国主導による全国的な対策が必要と考えられた。(著者抄録)
  • 判定時間を短縮した新しいインフルエンザ迅速診断キット「クイックナビ-Flu2」の評価
    市川 正孝, 三田村 敬子, 安倍 隆, 岡田 隆滋, 岡田 隆文, 後藤 泰浩, 迫田 義博, 佐藤 勇, 時田 章史, 豊田 茂, 中尾 歩, 藤枝 俊之, 松井 忠孝, 松永 貞一, 山崎 雅彦, Yuan Qian, Le Mai, 齋藤 玲子 医学と薬学 74 (10) 1299 -1310 2017年09月 [査読無し][通常論文]
     
    新しいインフルエンザ抗原迅速診断キット「クイックナビ-Flu2」(デンカ生研株式会社)の性能評価を行った。本品は着色ラテックス粒子を用いたイムノクロマト法を原理とした試薬であり、最終陰性判定時間が5分と従来品に比べ短縮され、かつラインが見やすくなったことが特徴である。基礎的検討では主な呼吸器感染症の原因ウイルスおよび細菌との交差反応は認められず、ヒトおよび動物由来のA型インフルエンザウイルスとの反応性も確認した。臨床性能試験(鼻腔拭い液n=248、鼻腔吸引液n=518、咽頭拭い液n=685)では、ウイルス分離培養を基準とした本品の感度はA型:94.8〜97.0%、B型:90.8〜97.8%、特異度はA型:98.4〜99.0%、B型:94.7〜98.3%で、全体一致率はいずれの検体種においても90%以上と良好な結果であった。また陽性となった症例の約90%が2分以内に判定が可能であり、5分という最終陰性判定時間を考慮するとインフルエンザ流行期の診療効率の改善に有用な診断キットであると考えられた。(著者抄録)
  • 小佐々隆志, 鳥居志保, 長坂孝雄, 山下麻依子, 落合絢子, 関口秀人, 齋藤明人, 塩川舞, 青木博史, 岡松正敏, 迫田義博 日本獣医学会学術集会講演要旨集 160th 398 -398 2017年08月30日 [査読無し][通常論文]
  • 岡松正敏, 日尾野隆大, 菊谷祐斗, 鈴木瑞穂, NGUYEN Thanh‐Lam, 松野啓太, 松野啓太, 迫田義博, 迫田義博 日本獣医学会学術集会講演要旨集 160th 382 -382 2017年08月30日 [査読無し][通常論文]
  • 藤野高志, 市川陽子, 三田村敬子, 市川正孝, 吉原成哲, 許斐康司, 安倍隆, 清水英明, 山崎雅彦, 八角有紀, 迫田義博 医学と薬学 74 (9) 1129‐1135 -1135 2017年08月27日 [査読無し][通常論文]
     
    われわれは、着色セルロース微粒子をコンジュゲートに使用し視認性を高め、判定までの時間を5分に短縮した「ファインビジョンInfluenza」の臨床検討を2013/2014シーズンに行い、報告した。今回は異なるシーズンである2016/2017シーズンで同様の検討を実施し、流行シーズン間での発熱時間に対する検出率の比較検討を行った。2016年12月から2017年3月まで、国内6ヶ所の医療機関を受診しインフルエンザウイルス感染が疑われた患者118名を対象とし、対照品として「クイックナビ-Flu」を使用した。ウイルス分離培養により69検体でA型を検出し、A型69株の亜型はすべてAH3であった。11検体でB型を検出し、Victoria系統9検体、Yamagata系統2検体であった。ウイルス分離培養を基準とすると、ファインビジョンの感度はA型98.6%(68/69)、B型100%(11/11)、対照品クイックナビの感度はA型97.1%(67/69)、B型100%(11/11)であり、特異度はともに100%(38/38)であった。発熱から採取までの経過時間を3、6、9、12、24、72時間後までに区切ると、A型においてファインビジョンは12時間までの累積感度は100%(28/28)、〜24時間までの累積で98.3%(57/58)、〜72時間までのトータルで98.6%(68/69)であった。B型ではすべての区で100%であった。既報告の2013/2014シーズン同様に2016/2017シーズン患者においても感染初期に相当する早期発熱時間から良好な検出率を示した また、2016年に発生した鳥インフルエンザウイルスH5N6亜型との反応性を検討し、ファインビジョンにおいて同株ならびにH5N1、H5N8亜型ウイルスとの反応を確認した。ファインビジョンは、流行シーズンやウイルス株によらずインフルエンザウイルスに対する良好な検出率を持つことが示され、臨床的有用性が改めて示された。(著者抄録)
  • 小笠原浩平, 渡辺有希子, NGUYEN Lam Thanh, 岡松正敏, 鈴木瑞穂, 迫田義博, 齊藤慶輔 北海道獣医師会雑誌 61 (8) 359 -359 2017年08月10日 [査読無し][通常論文]
  • 迫田義博 北海道獣医師会雑誌 61 (8) 364 2017年08月10日 [査読無し][通常論文]
  • 2016-2017年冬季に北日本で野鳥及び飼育鳥から分離されたH5N6高病原性鳥インフルエンザウイルスの性状解析
    岡松 正敏, 日尾野 隆大, 菊谷 祐斗, 鈴木 瑞穂, Nguyen Thanh-Lam, 松野 啓太, 迫田 義博 日本獣医学会学術集会講演要旨集 160回 382 -382 2017年08月 [査読無し][通常論文]
  • 2.3.4.4高病原性鳥インフルエンザウイルスに対する新規モノクローナル抗体を用いた免疫クロマトグラフィーキットによるH5ヘマグルチニンの迅速かつ広範囲検出(Rapid and broad detection of H5 hemagglutinin by an immunochromatographic kit using novel monoclonal antibody against a 2.3.4.4 highly pathogenic avian influenza virus)
    Nguyen Thanh-Lam, 中石 和成, 本島 桂子, 大河原 彩子, 日尾野 隆大, 松野 啓太, 岡松 正敏, 高田 礼人, 喜田 宏, 迫田 義博 日本獣医学会学術集会講演要旨集 160回 384 -384 2017年08月 [査読無し][通常論文]
  • H13鳥インフルエンザウイルスの遺伝子と抗原の性状(Genetic and antigenic characterization of H13 avian influenza viruses)
    Wang Zu Jyun, 菊谷 祐斗, Nguyen Thanh-Lam, 松野 啓太, 岡松 正敏, 迫田 義博 日本獣医学会学術集会講演要旨集 160回 385 -385 2017年08月 [査読無し][通常論文]
  • 国内の牛ウイルス性下痢・粘膜病(BVD-MD)ワクチン接種牛におけるHoBi-likeウイルス(牛ウイルス性下痢ウイルス(BVDV)3型)に対する交差反応性
    小佐々 隆志, 鳥居 志保, 長坂 孝雄, 山下 麻依子, 落合 絢子, 関口 秀人, 齋藤 明人, 塩川 舞, 青木 博史, 岡松 正敏, 迫田 義博 日本獣医学会学術集会講演要旨集 160回 398 -398 2017年08月 [査読無し][通常論文]
  • Rapid and broad detection of H5 hemagglutinin by an immunochromatographic kit using novel monoclonal antibody against a 2.3.4.4 highly pathogenic avian influenza virus(和訳中)
    Nguyen Thanh-Lam, 中石 和成, 本島 桂子, 大河原 彩子, 日尾野 隆大, 松野 啓太, 岡松 正敏, 高田 礼人, 喜田 宏, 迫田 義博 日本獣医学会学術集会講演要旨集 160回 384 -384 2017年08月 [査読無し][通常論文]
  • Genetic and antigenic characterization of H13 avian influenza viruses(和訳中)
    Wang Zu Jyun, 菊谷 祐斗, Nguyen Thanh-Lam, 松野 啓太, 岡松 正敏, 迫田 義博 日本獣医学会学術集会講演要旨集 160回 385 -385 2017年08月 [査読無し][通常論文]
  • 簡易キット陰性と判定された死亡野鳥からの高病原性鳥インフルエンザウイルス伝播の可能性
    小笠原 浩平, 渡辺 有希子, Nguyen Lam Thanh, 岡松 正敏, 鈴木 瑞穂, 迫田 義博, 齊藤 慶輔 北海道獣医師会雑誌 61 (8) 359 -359 2017年08月 [査読無し][通常論文]
  • 高病原性鳥インフルエンザの最新情報 家きん防疫と野鳥監視の現場から 高病原性鳥インフルエンザ最新情報について
    迫田 義博 北海道獣医師会雑誌 61 (8) 364 -364 2017年08月 [査読無し][通常論文]
  • インフルエンザウイルス抗原迅速検出キット「ファインビジョンInfluenza」の流行シーズン間の検出率および新たに報告された鳥インフルエンザウイルスに対する反応性に関する検討
    藤野 高志, 市川 陽子, 三田村 敬子, 市川 正孝, 吉原 成哲, 許斐 康司, 安倍 隆, 清水 英明, 山崎 雅彦, 八角 有紀, 迫田 義博 医学と薬学 74 (9) 1129 -1135 2017年08月 [査読無し][通常論文]
     
    われわれは、着色セルロース微粒子をコンジュゲートに使用し視認性を高め、判定までの時間を5分に短縮した「ファインビジョンInfluenza」の臨床検討を2013/2014シーズンに行い、報告した。今回は異なるシーズンである2016/2017シーズンで同様の検討を実施し、流行シーズン間での発熱時間に対する検出率の比較検討を行った。2016年12月から2017年3月まで、国内6ヶ所の医療機関を受診しインフルエンザウイルス感染が疑われた患者118名を対象とし、対照品として「クイックナビ-Flu」を使用した。ウイルス分離培養により69検体でA型を検出し、A型69株の亜型はすべてAH3であった。11検体でB型を検出し、Victoria系統9検体、Yamagata系統2検体であった。ウイルス分離培養を基準とすると、ファインビジョンの感度はA型98.6%(68/69)、B型100%(11/11)、対照品クイックナビの感度はA型97.1%(67/69)、B型100%(11/11)であり、特異度はともに100%(38/38)であった。発熱から採取までの経過時間を3、6、9、12、24、72時間後までに区切ると、A型においてファインビジョンは12時間までの累積感度は100%(28/28)、〜24時間までの累積で98.3%(57/58)、〜72時間までのトータルで98.6%(68/69)であった。B型ではすべての区で100%であった。既報告の2013/2014シーズン同様に2016/2017シーズン患者においても感染初期に相当する早期発熱時間から良好な検出率を示した また、2016年に発生した鳥インフルエンザウイルスH5N6亜型との反応性を検討し、ファインビジョンにおいて同株ならびにH5N1、H5N8亜型ウイルスとの反応を確認した。ファインビジョンは、流行シーズンやウイルス株によらずインフルエンザウイルスに対する良好な検出率を持つことが示され、臨床的有用性が改めて示された。(著者抄録)
  • 豚丹毒生ワクチン針刺し後に右膝慢性非特異性滑膜炎をきたした1例
    渡辺 尭仁, 小野寺 智洋, 新井 隆太, 亀田 敏明, 薮内 康史, 近藤 英司, 岩崎 倫政, 迫田 義博 北海道整形災害外科学会雑誌 59 (1) 166 -167 2017年08月 [査読無し][通常論文]
  • 高病原性鳥インフルエンザの最新情報 家きん防疫と野鳥監視の現場から 高病原性鳥インフルエンザ最新情報について
    迫田 義博 北海道獣医師会雑誌 61 (8) 364 -364 2017年08月 [査読無し][通常論文]
  • 迫田義博, 迫田義博, 小山田孝嘉, 小山田孝嘉 臨床とウイルス 45 (2) S72 -S72 2017年04月21日 [査読無し][通常論文]
  • 迫田義博, 迫田義博, 迫田義博 最新医学 72 (4) 546‐553 -553 2017年04月10日 [査読無し][通常論文]
     
    H5またはH7亜型のA型インフルエンザウイルスのうち,ニワトリに対して致死的な病原性を示すものを高病原性鳥インフルエンザウイルスと呼ぶ.常在国である中国や東南アジアでは,このウイルスが鳥からヒトに感染し,死亡例も多数報告されている.しかし,このウイルスはヒトからヒトへの感染が成立しないので,飼養されているニワトリやアヒルへの対策を徹底すれば,ヒトへの感染リスクはなくなる.つまり,家禽における感染源対策の徹底がOne Health実現の要である.(著者抄録)
  • 熊谷卓司, 中山哲夫, 奥野良信, 森川佐依子, 加瀬哲男, 纐纈律子, 吉井洋紀, 本條健太, 迫田義博, 喜田宏, 庵原俊昭 日本小児感染症学会総会・学術集会プログラム・抄録集 49th 136 2017年 [査読無し][通常論文]
  • 豚丹毒生ワクチン針刺し後に右膝慢性滑膜炎をきたした1例
    渡辺 尭仁, 小野寺 智洋, 新井 隆太, 亀田 敏明, 薮内 康史, 近藤 英司, 岩崎 倫政, 迫田 義博 北海道医学雑誌 91 (2) 88 -89 2016年11月 [査読無し][通常論文]
  • 豚丹毒生ワクチン針刺し後に右膝慢性滑膜炎をきたした1例
    渡辺 尭仁, 小野寺 智洋, 新井 隆太, 亀田 敏明, 薮内 康史, 近藤 英司, 岩崎 倫政, 迫田 義博 北海道医学雑誌 91 (2) 88 -89 2016年11月 [査読無し][通常論文]
  • 渡辺尭仁, 小野寺智洋, 新井隆太, 亀田敏明, 薮内康史, 近藤英司, 岩崎倫政, 迫田義博 北海道医学雑誌 91 (2) 88‐89 2016年11月01日 [査読無し][通常論文]
  • 塩川舞, 内山汐里, 長井誠, 長井誠, 片山幸枝, 水谷哲也, 迫田義博, 福所秋雄, 青木博史 日本獣医学会学術集会講演要旨集 159th 388 -388 2016年08月30日 [査読無し][通常論文]
  • 迫田義博, 迫田義博, BAZARRAGCHAA Enkhbold, MUNKHDUUREN Shatar, 若森史穂, 日尾野隆大, 松野啓太, 松野啓太, 岡松正敏, BATCHULUUN Damdinjav, 梅村孝司 日本獣医学会学術集会講演要旨集 159th 388 -388 2016年08月30日 [査読無し][通常論文]
  • 堀本泰介, 日尾野隆大, 目堅博久, 小田切友葉, 雷志皓, 遠藤麻衣子, 上間亜希子, 小林知也, CHAMBERS James, 内田和幸, 西原真杉, 乗峰潤三, 猪島康雄, 彦野弘一, 村上賢二, 佐藤礼一郎, 村上裕信, 阪口雅弘, 安藤貴朗, 乙丸孝之介, 小澤真, 石井一功, 迫田義博, 村上晋 日本獣医学会学術集会講演要旨集 159th 386 -386 2016年08月30日 [査読無し][通常論文]
  • 高橋望, 西根薫, 塩川舞, 迫田義博, 福所秋雄, 青木博史 日本獣医学会学術集会講演要旨集 159th 374 -374 2016年08月30日 [査読無し][通常論文]
  • 柴田明弘, 日尾野隆大, 福原久江, 住吉理穂, 大河原彩子, 松野啓太, 松野啓太, 岡松正敏, 迫田義博, 迫田義博, 尾坂優之 日本獣医学会学術集会講演要旨集 159th 382 -382 2016年08月30日 [査読無し][通常論文]
  • ワクチン接種後の鶏におけるH5鳥インフルエンザウイルスの抗原多様性の選択(Selection of antigenic variants of H5 avian influenza viruses in vaccinated chickens)
    Nguyen Thanh-Lam, 西 達也, 七戸 新太郎, Chu Duc-Huy, 日尾野 隆大, 松野 啓太, 岡松 正敏, 喜田 宏, 迫田 義博 日本獣医学会学術集会講演要旨集 159回 371 -371 2016年08月 [査読無し][通常論文]
  • 田中良子, 信本聖子, 立花智, 迫田義博, 西英機 臨床獣医 34 (6) 25‐28 -28 2016年06月01日 [査読無し][通常論文]
     
    ウシウイルス性下痢ウイルス(BVDV)の主な感染源はBVDB持続感染牛(PI牛)であり、PI牛の摘発、淘汰は清浄化のため重要である。BVDV抗原検出ELISAは従来の検査法に比べ簡易で迅速に行えることから、ELISAと従来法の遺伝子検査及びウイルス分離検査との結果を比較した。北海道十勝管内で採取された野外血清材料で、RT-PCRとウイルス分離を行った。抗原検査としてMDBK細胞、MDBK-SY細胞、またはBFM細胞のいずれかに被験血清を接種し、細胞を固定後、免疫染色法により抗原を検出した。また、被験血清のBVDV1型及び2型に対する中和抗体を、MDBK-SY細胞を用いて血清希釈法により測定した。ELISAとRT-PCRの一致率は0.77、ELISAとウイルス分離は0.74で、ELSIAとRT-PCRの間では採材月齢が5ヵ月齢以上になると完全に一致した。また、ELISA陰性でRT-PCR陽性の8頭全てと、ELISA陽性でウイルス分離陰性の8検体の内6検体が中和抗体を保有していた。ELISAはRTーPCRより劣るが、ウイルス分離よりは中和抗体の影響を受けにくいと考えられた。
  • 熊谷卓司, 中山哲夫, 奥野良信, 加瀬哲男, 森川佐依子, 迫田義博, 迫田義博, 喜田宏, 管秀, 庵原俊昭 日本ワクチン学会学術集会プログラム・抄録集 20th 83 2016年 [査読無し][通常論文]
  • 渡辺尭仁, 小野寺智洋, 新井隆太, 迫田義博, 亀田敏明, 薮内康史, 近藤英司, 岩崎倫政 北海道整形災害外科学会 131st 103 2016年 [査読無し][通常論文]
  • 田村友和, RUGGLI Nicolas, 松野啓太, 松野啓太, 岡松正敏, 迫田義博, 迫田義博 日本獣医学会学術集会講演要旨集 158th 346 -346 2015年08月30日 [査読無し][通常論文]
  • 小笠原浩平, 岡松正敏, 日尾野隆大, 七戸新太郎, 栗林沙弥, 市川貴也, 西達也, CHU Duc‐Huy, 鈴木瑞穂, 遠藤真由美, 田中和之, 谷川力, 喜田宏, 喜田宏, 喜田宏, 迫田義博, 迫田義博, 迫田義博 日本獣医学会学術集会講演要旨集 158th 333 -333 2015年08月30日 [査読無し][通常論文]
  • 中務陽裕, 来馬浩二, 鈴木瑞穂, 日尾野隆大, 小山田孝嘉, 岡松正敏, 迫田義博, 迫田義博 日本獣医学会学術集会講演要旨集 158th 329 -329 2015年08月30日 [査読無し][通常論文]
  • 日尾野隆大, 岡松正敏, 五十嵐学, 五十嵐学, MCBRIDE Ryan, DE VIRES Robert, PAULSON James, 松野啓太, 松野啓太, 迫田義博, 迫田義博, 喜田宏, 喜田宏, 喜田宏 日本獣医学会学術集会講演要旨集 158th 332 2015年08月30日 [査読無し][通常論文]
  • 松野啓太, 松野啓太, 下田宙, 鳥居志保, 邱永晋, 中尾亮, 梶原将大, 岡松正敏, 迫田義博, 迫田義博, 奥村敦, 奥村敦, 高田礼人, 高田礼人, 前田健, 海老原秀喜 日本獣医学会学術集会講演要旨集 158th 344 2015年08月30日 [査読無し][通常論文]
  • 2014年のベトナムにおける介入有りまたは介入なしの生鳥市場にて単離された鳥インフルエンザウイルスの性状解析(Characterization of avian influenza viruses isolated in live bird markets with and without intervention in Vietnam in 2014)
    Chu Duc-Huy, 岡松 正敏, 松野 啓太, 日尾野 隆大, 小笠原 浩平, 鈴木 瑞穂, Nguyen Thanh Lam, 喜田 宏, 迫田 義博 日本獣医学会学術集会講演要旨集 158回 329 -329 2015年08月 [査読無し][通常論文]
  • 渡り鳥から検出された新型ロタウイルスAの遺伝学的解析
    藤井 祐至, 岡寺 康太, 三竹 博道, 伊藤 直人, 岡田 和真, 中川 賢人, 岡崎 克則, 迫田 義博, 高田 礼人, 小澤 真, 正谷 達謄, 杉山 誠 日本獣医学会学術集会講演要旨集 158回 371 -371 2015年08月 [査読無し][通常論文]
  • 迫田 義博 生体の科学 66 (4) 301 -304 2015年07月 [査読無し][通常論文]
  • 日尾野隆大, 岡松正敏, 五十嵐学, 五十嵐学, MCBRIDE Ryan, DE VIRES Robert P, PAULSON James C, 迫田義博, 迫田義博, 喜田宏, 喜田宏 日本糖質学会年会要旨集 34th 173 2015年07月01日 [査読無し][通常論文]
  • インフルエンザのグローバルサーベイランス
    迫田 義博 感染・炎症・免疫 45 (2) 116 -123 2015年07月 [査読無し][通常論文]
  • 全粒子ワクチンは複数のクレードのH5N1高病原性鳥インフルエンザウイルスに対する記憶免疫反応を誘導する
    仲山 美沙子, 七戸 新太郎, 伊藤 靖, 石垣 宏仁, 北野 光崇, 有方 雅彦, Pham Van Loi, 石田 英晃, 北川 直子, 小笠原 一誠, 土屋 英明, 中村 紳一朗, 岡松 正敏, 迫田 義博, 市川 貴也, 喜田 宏, Le Quynh Mai, 伊藤 睦美, 河岡 義裕 滋賀医学 37 146 -146 2015年03月 [査読無し][通常論文]
  • 岡松 正敏, 迫田 義博, 喜田 宏 化学療法の領域 30 (12) 25 -32 2014年12月 [査読無し][通常論文]
  • 田村友和, RUGGLI Nicolas, LINGER Matthias, 長島尚史, 峯淳貴, 岡松正敏, HOFMANN Martin A, SUMMERFIELD Artur, 喜田宏, 迫田義博 日本ウイルス学会学術集会プログラム・抄録集 62nd 250 2014年10月31日 [査読無し][通常論文]
  • 柳田里澄, 岡松正敏, 日尾野隆大, 迫田義博, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 62nd 155 2014年10月31日 [査読無し][通常論文]
  • 岡松正敏, 日尾野隆大, 五十嵐学, DE VRIES Robert, 西原祥子, 高瀬明, PAULSON James C, 迫田義博, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 62nd 154 2014年10月31日 [査読無し][通常論文]
  • 安井文彦, 宗片圭祐, 倉石武, 服部正策, 藤幸知子, 米田美佐子, 迫田義博, 喜田宏, 甲斐知恵子, 小原道法 日本ウイルス学会学術集会プログラム・抄録集 62nd 235 2014年10月31日 [査読無し][通常論文]
  • 吉田玲子, 伊藤靖, 七戸新太郎, 小笠原一誠, 日尾野隆大, 岡松正敏, 迫田義博, 喜田宏, LE Mai Quynh, 河岡義裕, 五十嵐学, 鈴木定彦, 高田礼人 日本ウイルス学会学術集会プログラム・抄録集 62nd 234 2014年10月31日 [査読無し][通常論文]
  • 七戸新太郎, 迫田義博, 西達也, 日尾野隆大, 岡松正敏, 伊藤靖, 小笠原一誠, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 62nd 154 2014年10月31日 [査読無し][通常論文]
  • 迫田義博, 大河原彩子, 日尾野隆大, 小笠原浩平, 岡松正敏, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 62nd 163 2014年10月31日 [査読無し][通常論文]
  • 塩川舞, 加藤あやの, 藤本悠理, 安部優里, 田村友和, 西根薫, 峯淳貴, 青木博史, 福所秋雄, 喜田宏, 迫田義博 日本獣医学会学術集会講演要旨集 157th 396 -396 2014年08月11日 [査読無し][通常論文]
  • 大河原彩子, 日尾野隆大, 小笠原浩平, 岡松正敏, 迫田義博, 喜田宏 日本獣医学会学術集会講演要旨集 157th 411 2014年08月11日 [査読無し][通常論文]
  • 岡松正敏, DE VRIES Robert, 日尾野隆大, 迫田義博, PAULSON C James, 喜田宏 日本獣医学会学術集会講演要旨集 157th 419 2014年08月11日 [査読無し][通常論文]
  • 田村友和, RUGGLI Nicolas, 長島尚史, 峯淳貴, 岡松正敏, SUMMERFIELD Artur, HOFMANN Martin A, 喜田宏, 迫田義博 日本獣医学会学術集会講演要旨集 157th 410 2014年08月11日 [査読無し][通常論文]
  • 塩川愛絵, CHANDIKA Gamage, 小泉信夫, 清水健太, 津田祥美, 迫田義博, 吉松組子, 有川二郎 日本獣医学会学術集会講演要旨集 157th 379 2014年08月11日 [査読無し][通常論文]
  • 日尾野隆大, 岡松正敏, 五十嵐学, 西原祥子, 高瀬明, 迫田義博, 喜田宏 日本糖質学会年会要旨集 33rd 62 2014年07月23日 [査読無し][通常論文]
  • 小山田孝嘉, 来馬浩二, 島田俊雄, 迫田義博, 喜田宏 日本DDS学会学術集会プログラム予稿集 30th 184 2014年07月01日 [査読無し][通常論文]
  • 伊藤靖, 仲山美沙子, 石垣宏仁, 石田英晃, 七戸新太郎, 岡松正敏, 迫田義博, 喜田宏, 喜田宏, 小笠原一誠 日本病理学会会誌 103 (1) 224 2014年03月26日 [査読無し][通常論文]
  • 伊藤靖, LOI Pham Van, 仲山美沙子, 石垣宏仁, 有方雅彦, 石田英晃, 北川直子, 小笠原一誠, 七戸新太郎, 岡松正敏, 迫田義博, 喜田宏, 喜田宏 滋賀医学 36 142 2014年03月20日 [査読無し][通常論文]
  • 迫田義博 家畜衛生学雑誌 39 (3) 99 -102 2013年11月22日 [査読無し][通常論文]
  • 斎野仁, 川内京子, 臼井章, 大野浩, 迫田義博, 田島誉士 日本獣医師会雑誌 66 (11) 791 -796 2013年11月20日 [査読無し][通常論文]
  • 迫田 義博 家畜衛生学雑誌 39 (3) 99 -102 2013年11月 [査読無し][通常論文]
  • 西根薫, 青木博史, 長井誠, 宮元みち子, 吉間昌行, 須藤貴之, 迫田義博, 福所秋雄 日本ウイルス学会学術集会プログラム・抄録集 61st 396 2013年10月29日 [査読無し][通常論文]
  • 安井文彦, 桑原一彦, 飛田良美, 棟方翼, 斉藤誠, 七戸新太郎, 迫田義博, 喜田宏, 阪口薫雄, 小原道法 日本ウイルス学会学術集会プログラム・抄録集 61st 153 2013年10月29日 [査読無し][通常論文]
  • 直亨則, 梶原将大, 丸山隼輝, 木村享史, MANZOOR Rashid, 村松美笑子, 岡松正敏, 宮本洋子, 吉田玲子, 迫田義博, 喜田宏, 高田礼人 日本ウイルス学会学術集会プログラム・抄録集 61st 150 2013年10月29日 [査読無し][通常論文]
  • 丸山隼輝, 宮本洋子, 吉田玲子, 前田健, 小川寛人, 迫田義博, 高田礼人 日本ウイルス学会学術集会プログラム・抄録集 61st 164 2013年10月29日 [査読無し][通常論文]
  • 青木博史, 西根薫, 吉間昌行, 須藤貴之, 迫田義博, 福所秋雄 日本獣医学会学術集会講演要旨集 156th 264 -264 2013年08月30日 [査読無し][通常論文]
  • 安部優里, 迫田義博, 三津橋和也, 田村友和, 小佐々隆志, 中村成幸, 喜田宏 日本獣医学会学術集会講演要旨集 156th 265 2013年08月30日 [査読無し][通常論文]
  • 市川貴也, 岡松正敏, 佐藤由佳, 日尾野隆大, 迫田義博, 喜田宏 日本獣医学会学術集会講演要旨集 156th 269 2013年08月30日 [査読無し][通常論文]
  • 小佐々 隆志, 青木 博史, 亀山 健一郎, 田村 友和, 安部 優里, 西根 薫, 戸高 玲子, 片山 和彦, 水谷 哲也, 白井 淳資, 石丸 雅敏, 中村 成幸, 長井 誠, 迫田 義博 日本獣医学会学術集会講演要旨集 156回 265 -265 2013年08月 [査読無し][通常論文]
  • 長井 誠, 立石 健太郎, 篠原 祐太, 鈴木 遊大, 福原 麻衣, 大森 啓太郎, 迫田 義博, 青木 博史, 水谷 哲也, 戸高 玲子, 片山 和彦, 白井 淳資 日本獣医学会学術集会講演要旨集 156回 265 -265 2013年08月 [査読無し][通常論文]
  • 日尾野隆大, 岡松正敏, 西原祥子, 高瀬明, 迫田義博, 喜田宏 日本獣医学会学術集会講演要旨集 155th 229 2013年03月04日 [査読無し][通常論文]
  • 曽田公輔, 笛吹達史, 宇野有紀子, 永井泰子, 尾崎弘一, 伊藤啓史, 山本直樹, 田村友和, 日尾野隆大, 岡松正敏, 迫田義博, 高田礼人, 村瀬敏之, 山口剛士, 伊藤壽啓 日本獣医学会学術集会講演要旨集 155th 83 2013年03月04日 [査読無し][通常論文]
  • 七戸新太郎, 岡松正敏, 迫田義博, 喜田宏 日本獣医学会学術集会講演要旨集 155th 229 2013年03月04日 [査読無し][通常論文]
  • 迫田義博, 三津橋和也, 田村友和, 長島尚史, 岡松正敏, NICOLAS Ruggli, SUGIRA Parchariyanon, WASANA Pinyochon, 喜田宏 日本獣医学会学術集会講演要旨集 155th 226 2013年03月04日 [査読無し][通常論文]
  • 和田 淳彦, 迫田 義博, 小山田 孝喜 Fuji Film research & development (58) 72 -76 2013年 [査読無し][通常論文]
  • 安井文彦, 宗片圭祐, 倉石武, 服部正策, 藤幸知子, 米田美佐子, 迫田義博, 喜田宏, 甲斐知恵子, 小原道法 日本ワクチン学会学術集会プログラム・抄録集 17th 87 2013年 [査読無し][通常論文]
  • 櫻井陽, 高山勝好, 野村奈美子, 迫田義博, 須田美彦, 小林行治, 阪口薫雄, 喜田宏, 小原道法, 芝崎太 日本分子生物学会年会プログラム・要旨集(Web) 36th WEB ONLY 3P-1007 2013年 [査読無し][通常論文]
  • Motofumi Shimizu, Satomi Yanase, O. O. Chang Myint, Masatoshi Okamatsu, Yoshihiro Sakoda, Hiroshi Kida, Hiroshi Takaku Journal of Vaccines and Vaccination 4 (6) 2013年 [査読無し][通常論文]
     
    Background: Intermittent outbreaks of highly pathogenic avian influenza virus (flu) infections illustrate the potential for pandemic spread of this deadly disease, thus making the development of sufficient supplies of safe vaccines a necessity. Influenza virus-like particles (Vlps) have been suggested as a promising non-egg or non-mammalian cell culture-based candidate for vaccination against flu. Vlps containing hemagglutinin have previously been shown to promote protection against homologous viral strains. In this report, we describe the development of an H5N1 flu Vlp vaccine involving only three flu viral structural proteins, (i.e., HA, NA, and M1), which were derived from an avian flu A/duck/Hokkaido/vac-1/2004 (H5N1) virus. The H5N1 Vlps produced from insect cells exhibited hemagglutination and neuraminidase activities and generated an immune response in BALB/c mice. We additionally performed viral challenge studies using chickens. Methodology and results: Vlps consisting of the hemagglutinin (HA), neuraminidase (NA), and matrix 1 (M1) proteins of A/duck/Hokkaido/vac-1/2004 (H5N1) were transferred using baculovirus within Spodoptera frugiperda (Sf9) cells. Mice were first immunized with Vlps, and the immune response was compared between animals vaccinated with HA and NA-HA-negative M1 Vlps. The IgG levels of HA-M1 Vlp- and NA-M1 Vlp-treated groups were observed, and 5-fold higher levels of H5N1-specific antibodies were induced in the groups of mice immunized with HA-NA-M1 Vlp. The HA-NA and HA-NA-M1 Vlps vaccines induced IgG2a and IgG2b antibodies as well as IgG1 antibodies, indicating that both Th1 and Th2 immune responses were induced. Furthermore, NA-M1 immunization induced IgG and IgG1 isotype antibodies and led to low levels of IgG2a and IgG2b. Additionally, all chickens immunized with HA-NA-M1 Vlp were protected against deadly infections with the highly pathogenic avian flu virus A/chicken/Yamaguchi/4/2004 (H5N1). Conclusions: Intramuscular administration of H5 Vlps conferred immunity against a deadly viral challenge. The H5 Vlp vaccine was more successful at raising Th1-biased protective responses, including IgG2a production. Thus, flu Vlps offer an important approach for immunization, especially if a pandemic occurs. Recognizing the current state of vaccination strategies, it is imperative to investigate the associated immunogenicity and defensive capabilities of H5 Vlps in comparison with inactivated whole virus and attenuated live H5N1 viruses. These results support the continued development of Vlps as a formulation for a vaccine against flu infection. © 2013 Shimizu M, et al.
  • 岡本成史, 竹中延之, 迫田義博, 岡松正敏, 山本直樹, ハリディ アーマド, 山田博司, 森康子, 喜田宏, 山西弘一 日本ウイルス学会学術集会プログラム・抄録集 60th 263 2012年10月31日 [査読無し][通常論文]
  • 田村友和, 長島尚史, 山本直樹, 岡松正敏, NICOLAS Ruggli, 迫田義博, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 60th 250 2012年10月31日 [査読無し][通常論文]
  • 七戸新太郎, 岡松正敏, 迫田義博, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 60th 167 2012年10月31日 [査読無し][通常論文]
  • 西根薫, 榎戸眞徒, 青木博史, 迫田義博, 福所秋雄 日本獣医学会学術集会講演要旨集 154th 251 -251 2012年08月31日 [査読無し][通常論文]
  • 山本 直樹, 迫田 義博 畜産技術 0 (686) 19 -24 2012年07月 [査読無し][通常論文]
  • 迫田 義博, 遠藤 真由美, 佐藤 由佳, 岡松 正敏, 喜田 宏 日本獣医師会雑誌 = Journal of the Japan Veterinary Medical Association 65 (4) 303 -305 2012年04月20日 [査読無し][通常論文]
     
    グルタルアルデヒドを主成分とする消毒薬の鳥インフルエンザウイルスに対する不活化効果を調べた.その結果,グルタルアルデヒドを主成分とする消毒薬は有機物が混入しても高い消毒効果が認められた.しかし,低温下ではその効果は低下した.またウイルスの不活化には,塩化ジデシルジメチルアンモニウムを主成分とする陽イオン系界面活性剤に比べ,作用時間をより長く必要とすることがわかった.以上の結果は,グルタルアルデヒドを主成分とする消毒薬を鳥インフルエンザウイルスに対して用いる場合には,有機物の有無に関わらずその効果が期待できるが,反応温度や反応時間を十分に考慮する必要があることを示している.
  • 迫田 義博 ウイルス 61 (2) 239 -248 2011年12月01日 [査読無し][通常論文]
  • 迫田 義博 グリーンテクノ情報 7 (2) 9 -13 2011年10月 [査読無し][通常論文]
  • 2009年のウズラ由来H7N6亜型高病原性鳥インフルエンザウイルスの感染経路の推定
    内田 裕子, 金平 克史, 真瀬 昌司, 竹前 喜洋, 渡辺 千晶, 笛吹 達史, 藤本 佳万, 伊藤 壽啓, 五十嵐 学, 伊藤 公人, 高田 礼人, 迫田 義博, 岡松 正敏, 山本 祐, 中村 菊保, 喜田 宏, 廣本 靖明, 津田 知幸, 西藤 岳彦 動物衛生研究成果情報 (10) 15 -16 2011年09月 [査読無し][通常論文]
  • 西根薫, 青木博史, 迫田義博, 福所秋雄 日本獣医学会学術集会講演要旨集 152nd 245 -245 2011年08月31日 [査読無し][通常論文]
  • 岡松正敏, 伊藤啓史, 内田裕子, 迫田義博, 山本直樹, 曽田公輔, 笛吹達史, 尾崎弘一, 山口剛士, 村瀬敏之, 伊藤壽啓, 西藤岳彦, 喜田宏 日本獣医学会学術集会講演要旨集 152nd 231 2011年08月31日 [査読無し][通常論文]
  • 西根 薫, 青木 博史, 迫田 義博, 福所 秋雄 獣医疫学雑誌 16 (1) 19 -20 2011年 [査読無し][通常論文]
     
    The purpose of this study was to detect and quantify bovine viral diarrhea virus (BVDV) quasispecies in field endemic BVDV strains, and to analyze a co-relation between quantity of these quasispieces and variety of clinical sign on bovine viral diarrhea virus infections.<BR>Forty five of BVDV isolates in Hokkaido prefecture were analyzed by the exaltation of Newcastle disease virus (END) method, the reverse plaque formation (RPF) method using vesicular stomatitis virus, and observation of cytopathic effect (CPE). As a result, these isolates investigated were divided into five groups. The first group is 10 isolates from which END phenomenon positive (E<SUP>+</SUP>) virus was only detected. The second is 25 isolates which consisted of E<SUP>+ </SUP>virus as major and END phenomenon negative (E<SUP>-</SUP>) virus as minor. The third is 7 isolates in which each virus was detected with same titer. The fourth is 2 isolates which showed only E<SUP>-</SUP> virus-positive. The fifth is 1 isolate which contained cp virus. In the quantitative analysis, it was shown that the ratio of E<SUP>-</SUP> virus against E<SUP>+</SUP> virus in the strain that contained each virus varied from 2 times to 435 times. These results suggest that BVDV field isolates not only consist of E<SUP>+</SUP> virus as major virus but also contain several quantity of E<SUP>-</SUP> virus as minor virus, and that E<SUP>-</SUP> virus exists frequently in the field. Moreover, it is interesting that the strains with E<SUP>-</SUP> virus as major are in the field, which will be a first report. On the other hand, any co-relations between quantity of E<SUP>-</SUP> virus in the field strain and epidemiological dynamism such as animal age, clinical symptoms of BVD-MD, or BVDV genotype, were not found unfortunately. However, there is the possibility of exerting an impact on symptom, because every isolates couldn&rsquo;t detect E<SUP>-</SUP>virus have been derived from asymptomatic infected cows.
  • 田村友和, 迫田義博, 吉野史, 杉田征彦, 岡松正敏, 長井誠, 伊藤美加, 青木博史, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 58th 275 2010年10月15日 [査読無し][通常論文]
  • 迫田 義博 農家の友 62 (10) 82 -84 2010年10月 [査読無し][通常論文]
  • 高橋菜都美, 青木博史, 松浦友紀子, 山本俊昭, 迫田義博, 福所秋雄 日本獣医学会学術集会講演要旨集 150th 234 -234 2010年09月01日 [査読無し][通常論文]
  • 田村友和, 迫田義博, 吉野史, 岡松正敏, 長井誠, 伊藤美加, 青木博史, 喜田宏 日本獣医学会学術集会講演要旨集 150th 234 -234 2010年09月01日 [査読無し][通常論文]
  • E. -O. Tseren-Ochir, B. Damdinjav, T. Sharkhuu, H. M. Kang, Y. Sakoda, B. Purevsuren, S. Ruuragchaa, Y. J. Lee, H. Kida, B. Khishgee, S. Sengee INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES 14 E164 -E165 2010年03月 [査読無し][通常論文]
  • 磯田 典和, 迫田 義博 農林水産技術研究ジャーナル 32 (12) 10 -15 2009年12月01日 [査読無し][通常論文]
  • T. Tanaka, Y. Sunden, G. Tanoue, K. Ochiai, Y. Sakoda, H. Kida, T. Umemura JOURNAL OF COMPARATIVE PATHOLOGY 141 (4) 277 -277 2009年11月 [査読無し][通常論文]
  • 磯田 典和, 迫田 義博, 喜田 宏 化学と生物 47 (5) 302 -304 2009年05月01日 [査読無し][通常論文]
  • 迫田 義博 農林水産技術研究ジャーナル 32 (3) 52 -56 2009年03月01日 [査読無し][通常論文]
  • 佐々木 崇, 坂元 隆一, 今村 孝, 坂口 正士, 瀧川 義康, 西條 加須江, 澤田 章, 萩原 純子, 土屋 耕太郎, 林 志鋒, 國米 則秀, 扇谷 年昭, 曽田 公輔, 磯田 典和, 迫田 義博, 喜田 宏 鶏病研究会報 44 (4) 170 -174 2009年02月25日 [査読無し][通常論文]
  • 岡松正敏, 迫田義博, 吉田裕美, 田中智久, 津田祥美, 磯田典和, 中山絵里, 苫米地大輔, 松野啓太, 梅村孝司, 高田礼人, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 56th 263 2008年10月01日 [査読無し][通常論文]
  • 岡松正敏, 迫田義博, 吉田裕美, 田中智久, 津田祥美, 磯田典和, 中山絵里, 苫米地大輔, 松野啓太, 梅村孝司, 高田礼人, 喜田宏 日本獣医学会学術集会講演要旨集 146th 193 2008年09月05日 [査読無し][通常論文]
  • 伊藤 美加, 長井 誠, 早川 裕二, 小前 博文, 村上 成人, 四ッ谷 正一, 浅倉 真吾, 迫田 義博, 喜田 宏 The journal of veterinary medical science 70 (9) 899 -906 2008年09月 [査読無し][通常論文]
     
    2007年8月,石川県金沢競馬場において馬インフルエンザが発生した.感染馬の症状は主に発熱(38.2-41.0℃)および鼻汁漏出で,呼吸器症状を示した馬はわずかであった.全ての競走馬は不活化ワクチンを接種しており,ワクチンにはH3N8馬インフルエンザウイルス,アメリカ系統のA/equine/La Plata/93株,同じくヨーロッパ系統のA/equine/Avesta/93株,およびH7N7馬インフルエンザのA/equine/Newmarket/1/77株が含まれていた.鼻腔スワブ材料からH3N8馬インフルエンザが分離され,A/equine/Kanazawa/1/2007と命名した.系統樹解析では,A/equine/Kanazawa/1/2007株はアメリカ系統のフロリダ亜系統に属した.さらに,HA1サブユニットのアミノ酸解析を行ったところ,同じアメリカ系統のワクチン株であるA/equine/La Plata/93株と比較して,BおよびEの抗原決定部位に4アミノ酸の置換が認められた.また,回復期の馬16頭から採材した血清を用いて赤血球凝集抑制反応を実施したところ,A/equine/Kanazawa/1/2007株とワクチン株間に1〜3管の差が認められた.これらの結果から,流行株とワクチン株に抗原性状の差が示唆されたが,わが国の現行市販ワクチンは罹患率の低下や発症期間の短縮に貢...
  • MANZOOR Rashid, 迫田 義博, 坂部 沙織, 望月 剛, 難波 靖治, 津田 祥美, 喜田 宏 The journal of veterinary medical science 70 (6) 557 -562 2008年06月 [査読無し][通常論文]
     
    H5高病原性鳥インフルエンザウイルス(HPAIV)と同様にH7亜型のHPAIVが世界各地の家禽に甚大な被害を及ぼしている.H7HPAIVの人への感染も報告されていることから,迅速な診断がHPAIの防疫のみならず公衆衛生の観点からも鍵となる.本研究では,H7HA分子上の異なるエピトープを認識する2つのモノクローナル抗体を用いたイムノクロマトグラフフイーによる迅速診断キットを開発した.本キットは調べたすべてのH7インフルエンザウイルスを特異的に検出し,H7以外の亜型のインフルエンザウイルスおよび他のウイルスや細菌とは反応しなかった.本キットはHPAIVA/chicken/Netherland/2586/03(H7N7)に感染したニワトリのスワブおよび臓器乳剤からH7HA抗原を検出した.以上より,本迅速診断キットはH7ウイルス感染によって起こるHPAIを特異的,高感度に診断できることが判ったので,HPAI発生農場での検査に有用と考えられる.
  • 田中 智久, 田上 銀平, 山崎 真大, 高島 郁夫, 迫田 義博, 落合 謙爾, 梅村 孝司 The journal of veterinary medical science 70 (6) 607 -610 2008年06月 [査読無し][通常論文]
     
    2005年度冬季に北海道で大量死した野鳥のうちの13羽について,病理検査とインフルエンザ,ウエストナイル両ウイルスの検出を行った.病理検査では全身性の急性循環障害が共通して認められ,ウイルス検出は陰性であった.これら検査結果,冬季限定の発生状況および文献検索から,融雪剤中毒の可能性が高いと考えられた.また,融雪剤を投与した鶏雛は急性経過で死亡し,野鳥と類似の病変を示した.鶏雛で血漿Na濃度の上昇があったことから,野鳥の死因の確定には罹患症例の電解質検査が必要と考えられた.
  • 伊藤 麻子, 迫田 義博, 亀山 健一郎, 山崎 幸夫, 臼井 章, 喜田 宏 日本獣医師会雑誌 = Journal of the Japan Veterinary Medical Association 61 (1) 39 -42 2008年01月20日 [査読無し][通常論文]
     
    牛ウイルス性下痢病(BVD)と牛伝染性鼻気管炎の予防に効果的なワクチン接種プログラムを評価するために、BVDに対して不活化抗原を含有する2つの市販混合ワクチンをそれぞれ抗体陰性牛に接種した。いずれのワクチンも初回接種後の牛にBVDウイルスおよび牛ヘルペスウイルス1に対する中和抗体がほとんど検出されなかったが、2回目の接種1ヵ月後に有意な抗体応答を認めた。その後、抗体価は時間の経過とともに漸減したが、初回接種から12ヵ月後に1回追加免疫を行うことにより抗体価が再上昇した。以上の成績より、抗体陰性牛に対する本疾病の効果的な予防には今回評価したワクチンは2回接種する必要があること、さらに年1回の追加接種が望ましいことが明らかになった。
  • Kouichi Ozaki, Yasuto Umeda, Shigeyuki Aoyama, Norikazu Isoda, Masatoshi Okamatsu, Yoshihiro Sakoda VACCINE 2008年 [査読無し][通常論文]
  • 新矢 恭子, 迫田 義博, 河岡 義裕 インフルエンザ 9 (1) 11 -19 2008年01月 [査読無し][通常論文]
  • 迫田 義博 日本獣医師会雑誌 = Journal of the Japan Veterinary Medical Association 60 (12) 817 -819 2007年12月20日 [査読無し][通常論文]
  • 迫田 義博 日本獣医師会雑誌 60 (12) 817 -819 2007年12月 [査読無し][通常論文]
  • 申 宰昊, 迫田 義博, 金 哉勲, 落合 謙爾, 梅村 孝司 The journal of veterinary medical science 69 (11) 1167 -1169 2007年11月 [査読無し][通常論文]
     
    不活化インフルエンザウイルスをウサギのクモ膜下および皮下に接種し,脳脊髄液および血清中の抗体価を測定した.クモ膜下接種による神経症状および病変はなかった.皮下免疫では脳脊髄液中の抗体価は上昇しなかった.クモ膜下接種では血清および脳脊髄液中の抗体価が上昇し,それらの抗体価は皮下接種群より高かった.従って,経神経伝播ウイルス感染症の予防には鞘内免疫がより有効であると考えられた.
  • 梶原将大, 梶原将大, 迫田義博, 迫田義博, 伊藤壽啓, 高田礼人, 岸田典子, 五十嵐学, 磯田典和, 磯田典和, 曽田公輔, 曽田公輔, 喜田宏, 喜田宏, 喜田宏 日本ウイルス学会学術集会プログラム・抄録集 55th 216 2007年10月01日 [査読無し][通常論文]
  • 亀山 健一郎, 迫田 義博 獣医畜産新報 60 (10) 818 -822 2007年10月 [査読無し][通常論文]
  • 梶原将大, 梶原将大, 迫田義博, 迫田義博, 伊藤壽啓, 高田礼人, 伊藤公人, 岸田典子, 五十嵐学, 磯田典和, 磯田典和, 曽田公輔, 曽田公輔, WEBSTER R.G, 喜田宏, 喜田宏, 喜田宏 日本獣医学会学術集会講演要旨集 144th 91 2007年08月27日 [査読無し][通常論文]
  • 迫田 義博, 吉見 泰, 黒川 知, 喜田 宏 日本獣医師会雑誌 = Journal of the Japan Veterinary Medical Association 60 (7) 519 -522 2007年07月20日 [査読無し][通常論文]
     
    市販消毒薬5品の鳥インフルエンザウイルス不活化効果を調べた。消毒薬はいずれもウイルスの亜型と病原性に関わらず、高希釈でウイルスの感染性を消失させた。希釈した薬液の凍結融解の繰り返しは消毒効果に影響を与えなかったが、低温下および有機物として鶏糞を添加した場合、消毒効果の減少が認められた。以上の結果から、試験に用いた消毒薬は反応温度や有機物の混入などの環境要因を十分に理解した上で適切に使用すれば鳥インフルエンザウイルスの不活化に有効であることがわかった。
  • 迫田 義博, 吉見 泰, 黒川 知 日本獣医師会雑誌 60 (7) 519 -522 2007年07月 [査読無し][通常論文]
     
    市販消毒薬5品の鳥インフルエンザウイルス不活化効果を調べた。消毒薬はいずれもウイルスの亜型と病原性に関わらず、高希釈でウイルスの感染性を消失させた。希釈した薬液の凍結融解の繰り返しは消毒効果に影響を与えなかったが、低温下および有機物として鶏糞を添加した場合、消毒効果の減少が認められた。以上の結果から、試験に用いた消毒薬は反応温度や有機物の混入などの環境要因を十分に理解した上で適切に使用すれば鳥インフルエンザウイルスの不活化に有効であることがわかった。
  • 迫田 義博, 喜田 宏 鶏病研究会報 43 (1) 32 -33 2007年05月25日 [査読無し][通常論文]
  • 松野 啓太, 迫田 義博, 亀山 健一郎, 玉井 久三, 伊藤 麻子, 喜田 宏 The journal of veterinary medical science 69 (5) 515 -520 2007年05月 [査読無し][通常論文]
     
    2000年から2006年までに12都道県で牛から分離された475株の牛ウイルス性下痢ウイルス(BVDV)の5'末端非翻訳領域の塩基配列を基にした分子疫学解析を行った.その結果,396株が遺伝子型1に分類され,さらに1a亜型(101株),1b亜型(163株),1c亜型(128株),1j亜型(3株)およびSo CP/75-like亜型(1株)に分けられた.残り79株は遺伝子型2に分類され,すべて2a亜型であった.2a亜型BVDVには高病原性株として報告されている北米分離株と高い相同性を有する株も2株含まれていた.しかし,2a亜型BVDVのほとんどは持続感染牛から分離され,高い死亡率を伴う急性感染例は見られなかった.また,475株すべての細胞病原性とそのウイルスが分解された牛の臨床症状をまとめた結果,細胞病原性株が分離された牛でも典型的な粘膜病変を示さない例や,非細胞病原性株が分陰された持続感染牛でもまったく臨床症状を示さない例が多数認められた.以上より,国内では多様な遺伝子型のBVDVが浸潤しており,ウイルスが感染した牛が示す臨床症状も多様であることがわかった.これらの結果から,適切なワクチンによる予防と積極的なサーベイランスが本病の対策として重要であると考えられる.
  • 迫田 義博, 関 令二, 喜田 宏 家畜衛生学雑誌 32 (2) 67 -70 2007年03月 [査読無し][通常論文]
  • 藤井 啓, 角本 千治, 小林 万里, 齋藤 幸子, 刈屋 達也, 渡邊 有希子, 迫田 義博, 喜田 宏, 鈴木 正嗣 The journal of veterinary medical science 69 (3) 259 -263 2007年03月 [査読無し][通常論文]
     
    ゼニガタアザラシの保護管理に役立てることを目的として,北海道の太平洋沿岸に生息する野生ゼニガタアザラシの,インフルエンザAウイルス感染に関する血清学的調査を行った.1998年から2005年にかけて,納沙布で231個体,厚岸で16個体,襟裳で75個体のサンプル血清が採取された.ELISAでは,納沙布のサンプルからのみ,インフルエンザAウイルスに対する抗体が検出された.抗体保有率は98年が11%(1/9),03年が3%(2/66),04年が12%(7/59),05年が6%(5/77)であり,散発的な感染の存在が示された.いずれの年にも,幼獣からの抗体の検出があったため,少なくとも90年代の終盤から近年まで,感染が繰り返されていると考えられた.HI検査によると,ELISA陽性であった15サンプルのうち,10サンプルからH3亜型に対する抗体が,2サンプルからH6亜型に対する抗体が検出された.H6亜型に対して陽性であった2サンプルはH3亜型に対しても陽性であり,この2個体はH3とH6亜型の両方に感染したと考えられる.H6亜型に対する抗体がアザラシ類で確認されたのは,本報告が初めてである.H6亜型はこれまで鳥類からのみ分離されているが,遺伝学的研究では哺乳類に感染する可能性が示唆されている.今後,ウイルス検出による確定診断を試みたい.
  • Jae-Ho Shin, Yoshihiro Sakoda, Jae Hoon Kim, Tomohisa Tanaka, Hiroshi Kida, Takashi Kimura, Kenji Ochiai, Takashi Umemura JOURNAL OF NEUROIMMUNOLOGY 178 114 -114 2006年09月 [査読無し][通常論文]
  • 迫田 義博 インフルエンザ 7 (3) 195 -200 2006年07月 [査読無し][通常論文]
  • 白 貴蓉, 迫田 義博, ムウイネ アーロン, 藤井 信之, 皆川 英孝, 喜田 宏 The journal of veterinary medical science 68 (1) 35 -40 2006年01月 [査読無し][通常論文]
     
    A型およびB型インフルエンザウイルスを特異的に検出する迅速診断キットの感度を向上させるため, A型ウイルスNP蛋白の59-130番アミノ酸領域およびB型ウイルスNP蛋白の72-191番アミノ酸領域を認識するモノクローン抗体を用いたエスプライン^[○!R]インフルエンザA&B-Nを開発した.本キットの検出限界は10^<2.0>-10^<2.7> pfu/テストであり, 従来キットに比べ, 4〜1,000倍感度が改善された.また本キットは近年アジア地域でヒトや家禽から分離された高病原性H5N1ウイルスを含むすべてのHA亜型のA型ウイルスならびに調べた15株すべてのB型ウイルス株と反応した.以上の成績から, 今回開発したエスプライン^[○!R]インフルエンザA&B-NはA型およびB型ウイルスを迅速かつ高感度に検出することがわかった.
  • 青木 博史, 迫田 義博, 中村 成幸, 鈴木 祥子, 福所 秋雄 The journal of veterinary medical science 66 (2) 161 -167 2004年02月 [査読無し][通常論文]
     
    ペスチウイルスは細胞病原性ウイルスと非細胞病原性ウイルスに分類される.本研究において,免疫沈降法及びウエスタンブロッティング法を用いて豚コレラウイルス感染細胞における非構造蛋白質NS2-3及びNS3を解析し,細胞病原性との関係を調べた.END現象を示した豚コレラウイルス(END陽性ウイルス)は,試験に用いたいずれの培養細胞にも細胞変性効果(CPE)を示さず,ウイルス接種後72時間目の細胞内に主にNS2-3が検出された.一方,END現象を示さないが,干渉現象を示す豚コレラウイルス(END陰性ウイルス)は無血清培養細胞であるFS-L3細胞及びCPK-NS細胞に明瞭なCPEを示し,ウイルス接種後72時間目の細胞内にNS3が優位に検出された.また,ALD-ENDウイルス(END陰性ウイルス)を接種したFS-L3細胞を経時的に解析した結果, NS2-3が開裂し,NS3がより強く検出されるにつれてCPEが強くなることが明らかとなった.以上の成績は,END現象を示さない豚コレラウイルスが無血清培養細胞で示す細胞病原性において,非構造蛋白質NS2-3の開裂が重要であることを示す.
  • 八重樫 岳司, 清宮 幸男, 迫田 義博, 関 慶久 日本獣医師会雑誌 = Journal of the Japan Veterinary Medical Association 57 (1) 31 -35 2004年01月20日 [査読無し][通常論文]
     
    1987年から2002年までの16年間に岩手県内21農場33頭の牛から分離された牛ウイルス性下痢ウイルス(BVDV)33株の5'末端非翻訳領域を分子系統的に解析した。分離株は遺伝子型別に17株が1a型、3株が1a'型、9株が1b型そして4株が2型に分類された。2型に分類された4株の塩基配列は同一であり、2型BVDVの病原性決定塩基と考えられている219および278番目の塩基は強毒型とは異なっていた。また、2型株が分離された牛に全身性の出血病変は観察されなかった。2001年に採取した県内145農場725頭の牛血清中に2型特異抗体は認められなかった。これらの結果は2型を含む多様な遺伝子型のBVDV株が県内に浸潤していること、および2型株の浸潤範囲は限局的であることを示唆する。
  • 玉井久三, 迫田義博, 青木博史, 中村成幸, 喜田宏 日本獣医学会学術集会講演要旨集 135th 131 -131 2003年03月25日 [査読無し][通常論文]
  • 鈴木祥子, 迫田義博, 関口秀人, 青木博史, 高橋周子, 西口明子, 衛藤真理子 日本獣医学会学術集会講演要旨集 132nd 180 -180 2001年09月07日 [査読無し][通常論文]
  • 迫田 義博 養豚の友 (389) 31 -34 2001年08月 [査読無し][通常論文]
  • 迫田 義博 日本豚病研究会報 = Proceedings of the Japanese Pig Veterinary Society 38 (0) 14 -17 2001年08月01日 [査読無し][通常論文]
  • 青木 博史, 石川 清康, 迫田 義博, 関口 秀人, 児玉 道, 鈴木 祥子, 福所 秋雄 The journal of veterinary medical science 63 (7) 751 -758 2001年07月 [査読無し][通常論文]
     
    豚コレラウイルス(CSFV)は一般的には非細胞病原性(noncp)であるが, 1982年にイノシシから分離されたCSFV WB82株は初代豚精巣細胞(STp)及び多くの豚由来株化細胞で細胞変性効果(CPE)を伴って増殖することが確認された. このWB82株がnoncp CSFVのメジャーな集団と細胞病原性(cp) CSFVのマイナーな集団の2種の生物型からなることが判明し, クローニングにより得たnoncp CSFV (WB82/E^+株)はEND現象を示した. CPBを示したWB82株感染細胞のみからsubgenomic (sg) RNAが検出された. 典型的な欠損干渉(Defective Interfering; DI)粒子のゲノムを示すsg RNAは, 完全粒子のCSFVゲノムのN^<pro>からNS2遺伝子領域(4764塩基)を欠損することが明らかとなった. また, WB82/E^+株感染STp細胞にsg RNAを導入すると明瞭なCPEが観察され, 他のnoncp CSFVであるALD株やGPE^-株感染細胞にsg RNAを導入した場合にも同様のCPEが認められた. このことから, noncp CSFVがヘルパーウイルスとなってsg RNA(DI粒子)が複製し, 細胞病原性に関与することが推測された. さらに, WB82株の細胞病原性がアポトーシスによることが示唆された.
  • 井上 亙, 迫田 義博 畜産技術 0 (552) 34 -35,図巻頭1p 2001年05月 [査読無し][通常論文]
  • 本道 栄一, 迫田 義博 動生協会々報 34 (1) 64 -66 2001年01月 [査読無し][通常論文]
  • 井上亙, 国保健浩, 迫田義博, 犬丸茂樹, 青木博史, 山田俊治, 吉井雅晃, 福所秋雄, 横溝祐一 日本獣医学会学術集会講演要旨集 130th 255 2000年09月07日 [査読無し][通常論文]
  • 青木博史, 石川清康, 関口秀人, 蒲生恒一郎, 迫田義博, 高橋周子, 鈴木祥子, 福所秋雄 日本獣医学会学術集会講演要旨集 128th 151 -151 1999年09月01日 [査読無し][通常論文]
  • 青木博史, 石川清康, 迫田義博, 関口秀人, 蒲生恒一郎, 鈴木祥子, 福所秋雄 日本獣医学会学術集会講演要旨集 127th 117 -117 1999年03月01日 [査読無し][通常論文]
  • FS-L3細胞を用いた豚コレラウイルスの新しいアッセイ法の確立
    Journal of Virological Methods. 70 (1) 93 -101 1999年 [査読無し][通常論文]
  • Yoshihiro Sakoda, Osamu Yamaguchi, Akio Fukusho Journal of Virological Methods 70 (1) 93 -101 1998年01月 [査読無し][通常論文]
     
    A new assay termed the dome disappearance method for classical swine fever virus (CSFV) using FS-L3 cells with serum-free culture medium was developed. The CSFV live vaccine GPE- strain grows well and shows a slight cytopathic effect (CPE) in FS-L3 cells. This CPE results in the disappearance of the unique fluid-filled multicellular domes on a single monolayer of FS-L3 cells. By using this phenomenon, dome disappearance, as a marker of infection, it was possible to determine the titers of CSFV and its neutralizing antibody. The virus titer determined by this method shows a good correlation with that determined by immunochemical and interference methods. Furthermore, the amount of neutralizing antibody measured by this method also correlated with that measured by the Exaltation of Newcastle Disease Virus (END) neutralizing method. The dome disappearance method developed in this experiment is a simple and safe procedure and has the great advantage that bovine serum, which may contain antibody against bovine viral diarrhea virus, is not necessary for the cultivation of FS-L3 cells.
  • 山口 修, 迫田 義博, 佐藤 満雄, 中村 成幸, 福所 秋雄 日本獣医師会雑誌 = Journal of the Japan Veterinary Medical Association 50 (11) 639 -644 1997年11月20日 [査読無し][通常論文]
  • 石川清康, 迫田義博, 児玉道, 飛河三冬, 土屋佳紀, 関口秀人, 青木博史, 鈴木祥子, 福所秋雄 日本獣医学会学術集会講演要旨集 124th 71 1997年09月 [査読無し][通常論文]
  • 中村 成幸, 坂本 研一, 迫田 義博, 嶋崎 智章, 井上 剛光, 小川 信雄, 福所 秋雄 The journal of veterinary medical science 59 (5) 361 -370 1997年05月 [査読無し][通常論文]
     
    細胞病原性牛ウイルス性下痢ウイルス(NADL株及びOsloss株)を6回連続的にクローンニングした純化ウイルス材料から逆プラック法を用いて非細胞病原性牛ウイルス性下痢ウイルスを検出した. この現象から, 細胞病原性ウイルスの増殖過程で, 非細胞病原性ウイルスが低率で産生されることが推定された. この現象を解明するために, 細胞病原性ウイルスRNAに組込まれている宿主細胞由来mRNAの動向についてRT-PCR法, 遺伝子クローニング, 塩基構造解析等の技術を用いて解析した. その結果, NADL株及びOsloss株から分離された非細胞病原性ウイルスでは, 真の親にあだる細胞病原性ウイルスのRNAに組込まれている宿主細胞由来mRNAが脱落していることが解明された. このことから, 細胞病原性牛ウイルス性下痢ウイルスは, その増殖に伴い, ウイルスRNAに組込まれている宿主細胞由来mRNAが脱落することによって細胞病原性型から非細胞病原性型に復帰変異するものと考えられる.
  • 青木博史, 迫田義博, 土屋佳紀, 勝二郁夫, 松浦善治, 高田礼人, 喜田宏, 杉山公宏, 福所秋雄 日本獣医学会学術集会講演要旨集 123rd 153 1997年03月 [査読無し][通常論文]

特許

受賞

  • 2016年 北海道大学 北海道大学研究総長賞
     
    受賞者: 迫田 義博
  • 2014年 北海道大学 北海道大学研究総長賞
     
    受賞者: 迫田 義博
  • 2013年03月 日本獣医学会 日本獣医学会賞
     「ペスチウイルスの分子疫学と病原性に関する研究」 
    受賞者: 迫田 義博
  • 2008年 若手農林水産研究者表彰
     「高病原性鳥インフルエンザの診断と予防法の開発に関する研究」 
    受賞者: 迫田 義博
  • 2006年 アジア獣医系大学協会 アジア獣医系大学協会賞
     「高病原性鳥インフルエンザの疫学と病原性に関する研究」 
    受賞者: 迫田 義博

共同研究・競争的資金等の研究課題

  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2007年 -2009年 
    代表者 : 迫田 義博, 青木 博史
     
    豚コレラウイルスの病原性発揮に関与すると考えられている自然免疫回避機構を分子レベルで解明することを目的とし、ウイルス非構造蛋白N^の点変異体や欠損体を作製し、1型IFNの産生抑制に必須なアミノ酸領域を決定した。このアミノ酸の変異は、(1)C112R、(2)D136N、(3)H5Y、L8F、P17Sのいずれかであることがわかった。また、この自然免疫の調節に関与するN^上のアミノ酸の変異は、豚における病原性発揮の要因の1つであることを明らかにした。
  • 文部科学省:科学研究費補助金(基盤研究(S))
    研究期間 : 2003年 -2006年 
    代表者 : 喜田 宏, 岡崎 克則, 河岡 義裕, 迫田 義博, 梅村 孝司, 伊藤 壽啓, 小笠原 一誠
     
    本研究は、家禽と家畜のインフルエンザの被害を未然に防ぐとともに、ヒトの新型インフルエンザウイルスの出現に備え、その予防と制圧に資することを目的とする。・動物インフルエンザのグローバルサーベイランスによるウイルス分布の解明2006年秋、日本、モンゴルにおいて採取された渡りガモおよびハクチョウの糞便材料からのウイルス分離を試みた。1,201検体の材料から合計55株のインフルエンザAウイルスを分離同定した。これらの分離株にはH5やH7亜型のインフルエンザウイルスは含まれていなかった。これまでのウイルス分離の成績と合わせると、H1-H16およびN1-N9までの144通りの組合せのうち、133通りのウイルスの系統保存を完了した。・インフルエンザウイルスの病原性決定因子の同定2006年夏、モンゴルの湖沼で死亡野烏が再び発見され、死亡したオオハクチョウおよびホオジロガモの臓器材料からH5N1亜型の高病原性鳥インフルエンザウイルスが分離された。分離されたウイルスは、2005年中国やモンゴルの野生水禽から分離された高病原性のH5N1ウイルスと8つの遺伝子分節すべてが近縁であった。また、このウイルスに対して哺乳動物が高い感受性を示すことが動物試験から明らかにした。・ベッドサイド早期迅速インフルエンザ診断法の開発A型インフルエンザウイルスH5およびH7亜型抗原を特異的に検出する簡易診断キットを開発...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2003年 -2005年 
    代表者 : 田島 誉士, 迫田 義博, 落合 謙爾
     
    自然発生の牛ウイルス性下痢症ウイルス(BVDV)持続感染牛(PI)の臨床症状と分離されたウイルスの遺伝子亜型との関係を調べた。1991〜2005年までの間に摘発された150検体について、BVDVの主要抗原であるE2をコードする遺伝子の塩基配列を解読し、遺伝子亜型を決定した。その結果、13検体が世界的にきわめて稀な1c亜型に分類された。これらの症例には、運動障害を主徴とする中枢神経異常の症状が高率に認められ、病理解剖によって大脳に肉眼病変が認められた症例もあった。また、糖尿病併発BVDV感染牛から検出されたBVDVはすべて1a亜型に分類され、それぞれが遺伝学的に非常に近縁であり、小クラスターを形成していた。以上のことから、BVDV感染に併発する中枢神経異常および糖尿病は、特定の遺伝子亜型に属するBVDVと密接な関連性があることが示唆された。1c亜型に属するBVDVとその病態との関連性を組織学的に検索したところ、1c亜型特異的な脳内局在は確認できなかったが、1cは他の亜型のBVDVよりも高率に大脳神経細胞内で確認された。定性PCRでは、BVDV遺伝子型に関係なく各臓器からウイルス遺伝子が検出されたが、定量PCRによって各臓器局在のウイルス量の違いは確認されなかった。また、PIで高率に認められる発育不良とBVDV感染との関係を検討した。外見上ほぼ正常なPIと著しい発育不良のPIとか...
  • 文部科学省:科学研究費補助金(若手研究(B))
    研究期間 : 2003年 -2004年 
    代表者 : 迫田 義博
     
    牛ウイルス性下痢ウイルス(BVDV)に感染した牛が致死的な粘膜病を発病する際には、ウイルス遺伝子内に宿主由来遺伝子が挿入することが明らかになっている。この宿主遺伝子の一つとしてcINS遺伝子がある。このcINS遺伝子から翻訳される蛋白は分子シャペロンとして機能し、BVDVの病原性発揮に関与していると考えられるが、詳細は不明である。本年度は、昨年作出した組換えcINS蛋白に対するモノクローン抗体、およびNS2-3蛋白発現プラスミドを用いて、cINS蛋白がNS2-3蛋白の開裂に直接作用するのかを明らかにするとともに、分子シャペロンであるcINS蛋白と相互作用すると考えられる新たな宿主因子をTwo Hybridシステムで検索した。その結果、cINS蛋白とNS2-3は直接結合することがわかった。しかし、NS2-3の開裂には宿主由来の蛋白が2つ必須であることが明らかになった。現在これらの宿主因子の機能解析を詳細に行っている。また、作製されたモノクローン抗体を利用して、cINS遺伝子がウイルスゲノムに取り込まれているウイルス株を野外ウイルス株から選択し、Nose株の病原性獲得メカニズムとの比較を行った。その結果、野外にはNose株と同様の病原性獲得メカニズムによって病原性を獲得したと思われるウイルスが1株確認された。さらに、BVDVと同じペスチウイルスに属する豚コレラウイルスの新たな細胞...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2001年 -2003年 
    代表者 : 田島 誉士, 山崎 真大, 大和 修, 迫田 義博
     
    過去十数年の間に欧米各国で分離された、牛ウイルス性下痢症ウイルス(BVDV)野外分離株の主要抗原であるE2をコードする領域を基に、遺伝子型を解析した。ドイツ北部で分離されたBVDVは、ほとんどが1bおよび1d亜型に分類された。検索した62BVDV中それぞれの占める割合は50.0および40.3%であった。1d亜型はドイツ国内に分布する独特の遺伝子型であると考えられた。北米での流行BVDVの遺伝子型を検討したところ、56例中26例(37.5%)がBVDV2であった。この比率は、日本および欧州における流行比率より非常に高く、BVDV2は北米特有の流行ウイルスである可能性が示唆された。これらのBVDV2はさらに大小二つの亜型(2aおよび2c)に分類することが可能であった。北米で分離されたBVDV1は、ほとんどが1b亜型に分類された。検索した32株中26株が1b亜型に分類された。古典的代表株の属する1a亜型に分類されたのは6株のみであった。さらに、今回確認された北米の1b亜型は、これまでに本研究で明らかにされてきた日本およびドイツで流行している1b亜型とは異なるクラスターを形成しており、この領域の遺伝子を解析することは、日独米の流行ウイルスを区別するための有用な手段になると考えられた。各国の流行パターンを遺伝子型で比較すると、日本は1aおよび1b、ドイツは1bおよび1d、北米は1bおよ...
  • 文部科学省:科学研究費補助金(基盤研究(A))
    研究期間 : 2000年 -2002年 
    代表者 : 喜田 宏, 高田 礼人, 河岡 義裕, 岡崎 克則, 伊藤 壽啓, 迫田 義博
     
    新型ウイルスの亜型予測に資するため、鳥類および動物インフルエンザウイルスの疫学調査を実施した。ロシア、モンゴル、中国および北海道で、渡りカモの糞便3,987検体を採取し、亜型の異なるインフルエンザAウイルス212株を分離した。宮城県のブタからH1N2ウイルスを分離した。北海道大学を含む動物インフルエンザセンター5機関で25株のH9ウイルス株を交換し、解析を共同で開始した。渡りカモのウイルス遺伝子を比較解析したところ、日本で分離されたH9インフルエンザウイルスと1996年に韓国でニワトリに被害をもたらしたウイルスが近縁であった。1995~1999年に中国のニワトリから分離されたH9N2ウイルスの遺伝子解析の結果、渡りカモのウイルスと異なる亜群に分類され、ノイラミニダーゼに欠損が認められた。内部蛋白遺伝子は1997年の香港の強毒H5N1ウイルスに内部蛋白遺伝子を供給したH9N2ウイルスの系統とは異なった。香港のブタ、カスピ海のアザラシの抗体調査を行い、インフルエンザウイルスが感染した成績を得た。インフルエンザウイルスの異種動物間伝播機構を明らかにするため、ニワトリ雛の気嚢継代によって得たニワトリ馴化株の遺伝子再集合体を作出し、ニワトリ肺における増殖性を調べた。HA遺伝子を入れ替えた遺伝子再集合体の増殖性に変化はなく、他の因子が関与することが示唆された。新型ウイルスの出現に備え世界...
  • ウイルス病の予防に関する研究
  • Study on prophylaxis of viral disease

教育活動情報

主要な担当授業

  • 感染症学特別研究Ⅰ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • ウイルス学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 獣医学部
    キーワード : ウイルスの生態、増殖、分類、病原性、宿主域、感染、発症、ウイルス感染症の予防、診断、治療、制圧、根絶
  • 感染症学特別演習
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 微生物学総論
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 獣医学部
    キーワード : 細菌、真菌、ウイルス、感染症、診断、予防
  • 研究倫理演習
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 基礎動物衛生学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 獣医学部
    キーワード : 食品の衛生管理、食品添加物、食中毒、HACCP、安全性評価、食品衛生行政
  • 人獣共通感染症対策専門特論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 感染症学特別研究ⅡA
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 感染症学特別研究ⅡB
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 海外インターンシップA
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 海外インターンシップB
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 国際感染症学コア科目ⅡB 越境性感染症学特論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 国際感染症学院
  • 獣医科学特別研究
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学研究科
  • 専門獣医科学特論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学研究科
  • 人獣共通感染症対策専門特論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学研究科
  • 獣医科学特論演習
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学研究科
  • 獣医科学基礎科目B 動物実験倫理特論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学研究科
  • 研究倫理演習
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学院
  • インターンシップ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学院
  • 専門獣医科学特論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 獣医学院
  • 研究・臨床セミナー
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 獣医学部
  • アドバンスト演習
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 獣医学部

大学運営

委員歴

  • 2018年10月 - 現在   国際獣疫事務局(OIE)高病原性鳥インフルエンザレファレンスラボラトリー   責任者
  • 2008年 - 現在   環境省鳥インフルエンザ等野鳥対策に係る専門家グループ会合 委員
  • 2013年 - 2014年   家禽疾病小委員会委員
  • 2007年 - 2009年   鳥インフルエンザパンフレット作成委員会 座長


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