研究活動情報

• Length and density of α2-3 sialyllactose-containing chains on glycopolymers determine receptor binding of avian influenza viruses
  Daiki Kobayashi; Takahiro Hiono; Ryota Adachi; Manabu Igarashi; Takahiko Matsushita; Norikazu Isoda; Yoshihiro Sakoda; Koji Matsuoka
  Archives of Virology, 171, 3, Springer Science and Business Media LLC, 2026年02月26日
  研究論文（学術雑誌）
• Neuraminidase of influenza A viruses induces global desialylation of host cells via its intracellular function.
  Daiki Kobayashi; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  Microbiology spectrum, e0332825, 2026年02月18日, ［国際誌］
  英語, 研究論文（学術雑誌）, The neuraminidase protein (NA) of influenza A viruses (IAVs) plays a role in the release of viruses from infected cells. NA on viral particles hydrolyzes sialylated glycans on the cell surface for viral budding. However, the maturation and intracellular functions of NA are poorly understood. To investigate how NA functions intracellularly, glycans displayed on IAV-infected cells were profiled by lectins, and global glycome alterations, accompanied by exposed terminal galactose and glycan recapping with α1-2 fucose, were found in the virus-infected cells. Since α1-2 fucosyltransferases are localized in the Golgi, these unique structures suggest a potential NA function in the IAV-infected cells. Functional analyses using antivirals and NA-expressing cells indicate that intracellular NA function is necessary for the glycome alterations. Time-course analyses in IAV-infected cells revealed that global desialylation and α1-2 fucosylation could be observed 5 h post-inoculation, corresponding to the timeframe of viral protein expression. These observations provide a novel theory of NA functions that NA obtains its enzymatic activity intracellularly before virus assembly and serves desialylated glycans for competitive glycosyltransferases, including α1-2 fucosyltransferases, as their acceptors, resulting in glycan recapping with α1-2 fucose. Hence, intracellular NA blocks the re-sialylation of glycans, promoting efficient virus release from infected cells by inhibiting the interaction between progeny virions and sialosides. This study further demonstrated the potential NA functions of limiting secondary IAV infection. These findings provide insights into the evolutionary strategies of IAVs for shaping the strict window of superinfection by NA functions under a balance between successful replication and reassortment.IMPORTANCEInfluenza A viruses (IAVs) exploit glycans for their replication cycle. The hemagglutinin protein uses sialic acid for viral attachment, and the neuraminidase protein (NA) hydrolyzes sialosides for virus release. However, the intracellular functions of NA are not well understood. This study demonstrated that intracellular NA induces global desialylation and glycan recapping with unique structures in IAV-infected cells. This suggests a novel mode of NA function during the IAV lifecycle, where virus particles are ready to be released at the assembly, and NAs no longer need to hydrolyze the sialic acids upon egress from the cells. Therefore, the present study provides novel and significant insights into the fundamental understanding of the lifecycle of IAV. Furthermore, as NA is a primary target for anti-influenza drugs, understanding the mechanism of intracellular NA function may also support the development of antivirals.
• Comparative evaluation of commercial enzyme-linked immunosorbent assay kits for antibody monitoring of classical swine fever virus in Japanese pig herds: performance assessment of domestic and foreign kits.
  Miki Koyasu; Keisuke Kuwata; Shuko Inoha; Yoko Kimura; Kaoru Hatate; Daiki Kobayashi; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  The Journal of veterinary medical science, 88, 2, 347, 354, 2026年02月01日, ［国内誌］
  英語, 研究論文（学術雑誌）, Classical swine fever (CSF) is a highly contagious disease in pigs, and vaccination with antibody monitoring is critical for its prevention. In this study, the effectiveness of two enzyme-linked immunosorbent assay (ELISA) kits for antibody detection against CSF virus (CSFV)-an indirect ELISA kit authorized in Japan in 2001 (N-kit) and a competitive ELISA kit additionally authorized in 2024 (I-kit)-was compared. For each ELISA kit, detection accuracy in terms of sensitivity, specificity and agreement rate, and quantitative accuracy were evaluated based on neutralizing antibody titers determined by serum neutralization tests. In addition, the impact of serum heat-inactivation at 56°C for 30 min on ELISA results was assessed. The results indicated that the I-kit showed the highest sensitivity and agreement rate in detection accuracy, whereas the N-kit showed the highest quantitative accuracy. Although blocking rates of the I-kit increased after heat-inactivation, high correlation rates between treated and untreated samples were confirmed for both kits, suggesting that heat-inactivation does not affect the final interpretation of the test results. These findings demonstrated that the I-kit is suitable for initial antibody screening in pigs due to its higher sensitivity, whereas the N-kit provides better quantitative accuracy, making it preferable for measuring antibody titers in sows. Therefore, the selection of an appropriate ELISA kit according to the purpose of antibody detection is necessary to ensure a more accurate evaluation of the effects of CSFV vaccination on preventing CSF in pig herds.
• Evaluation of the Efficacy of Low-Concentration Gaseous Chlorine Dioxide in Inactivating Airborne H5 High Pathogenicity Avian Influenza Virus in Vivo Model.
  Yik Lim Hew; Norikazu Isoda; Takanori Miura; Takahiro Hiono; Yoshihiro Sakoda
  Food and environmental virology, 18, 1, 4, 4, 2026年01月23日, ［国際誌］
  英語, 研究論文（学術雑誌）, H5 high pathogenicity avian influenza virus (HPAIV) continues to spread globally, causing several high pathogenicity avian influenza (HPAI) outbreaks in poultry and significant economic losses. Biosecurity measures that prevent the introduction of HPAIV represent a top priority for controlling HPAI outbreaks on poultry farms. Although these measures are crucial for minimizing HPAI introduction, outbreaks of viral infection on poultry farms persist, underscoring the importance of continuously improving biosecurity protocols. Therefore, safe and effective microbicide disinfectants could play an essential role in reducing viral spread by inactivating viral particles on surfaces and in the air. This study assessed the efficacy of gaseous chlorine dioxide (ClO2) against H5 HPAIV under both gaseous ClO2 inactivation setting and in vivo conditions. In the gaseous ClO2 inactivation setting, only low virus titers were recovered (< 0.5-1.5 log10 TCID50/mL) when H5 HPAIV aerosols were exposed to gaseous ClO2 (0.05 ppmv, 0.14 mg/m3) for 5 min, corresponding to an approximately 2.0-3.0 log10 reduction. Furthermore, in vivo, all chicks exposed to aerosolized H5 HPAIV, which were treated with 0.1 ppmv gaseous ClO2, survived for 14 days post-challenge, demonstrating complete protection against the virus. The minimum effective concentration of gaseous ClO2 was 0.01 ppmv for 5 min of inactivation in the inactivation setting, and 0.05 ppmv for 5 min in vivo, indicating that relatively low concentrations are sufficient for effective viral inactivation. Therefore, gaseous ClO2 was effective at inactivating aerosolized H5 HPAIV and has potential for use as a disinfectant to prevent HPAIV introduction into poultry. (245/250) words.
• Characterization of H5N1 high pathogenicity avian influenza virus belonging to clade 2.3.4.4b isolated from Ezo red fox in Japan in a mouse model.
  Shintaro Shichinohe; Takahiro Hiono; Yasushi Itoh; Kosuke Takada; Yurie Kida; Pei Wang; Daisuke Motooka; Norikazu Isoda; Ayato Takada; Yoshihiro Sakoda; Tokiko Watanabe
  Microbiology spectrum, 14, 1, e0109725, 2026年01月06日, ［国際誌］
  英語, 研究論文（学術雑誌）, H5N1 high pathogenicity avian influenza virus (HPAIV) has spread in wild birds and poultry worldwide. H5N1 HPAIV belonging to the currently predominant clade 2.3.4.4b has infected not only birds but also mammals (wild and domestic animals), with several human infections also being reported, raising concerns for public health. In 2022, a clade 2.3.4.4b H5N1 HPAIV strain, A/Ezo red fox/Hokkaido/1/2022 (H5N1; Fox/Hok/1/22), was isolated from an Ezo red fox (Vulpes vulpes schrencki) in Hokkaido, Japan; this was the first reported case of clade 2.3.4.4b H5N1 HPAIV isolation from a mammalian species in Japan. Several amino acid substitutions in the PB2 protein play an important role in the adaptation of avian influenza viruses to mammals, but Fox/Hok/1/22 PB2 does not have any of these well-known mammalian-adapting PB2 substitutions. Here, we investigated the biological properties of Fox/Hok/1/22 in a mouse model and found that this virus was highly virulent in mice and replicated well in multiple organs, including the lungs and brain. We then examined whether viruses isolated from these organs acquired known mammalian-adapting PB2 amino acid substitutions, such as PB2 E627K. Deep sequencing analysis of viral RNA from mouse brain and lungs revealed that virus with PB2-627E was predominant in three of four mice, whereas the PB2-627K substitution was predominant in one mouse. These results indicate that Fox/Hok/1/22 is highly virulent in mice despite lacking known PB2 substitutions involved in mammalian adaptation.IMPORTANCEThe H5N1 avian influenza virus has caused severe disease in birds worldwide and is now spreading to mammals, including humans. In 2022, this virus was detected for the first time in an Ezo red fox in Japan. To understand its potential impact on mammals, we studied this virus in mice and found that it caused severe illness, spreading to multiple organs, including the lungs and brain. Surprisingly, despite lacking genetic mutations typically associated with mammalian adaptation, the virus was highly virulent in mice. This finding suggests that the H5N1 virus may pose a greater threat to mammals, including humans, than previously thought. Given their continued spread among wild and domestic animals, our findings underscore the urgent need to monitor how recent H5N1 viruses behave in mammals.
• Introduction and inter-species transmission dynamics of high pathogenicity avian influenza H5N1 viruses in Japan 2021-25.
  Yik Lim Hew; Claire Guinat; Manon Couty; Diletta Fornasiero; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  Virus evolution, 12, 1, veag005, 2026年, ［国際誌］
  英語, 研究論文（学術雑誌）, High pathogenicity avian influenza virus impacts poultry and wild birds worldwide. Since the introduction of clade 2.3.4.4b H5N1 isolates in Japan in late 2021, new cases have been reported in domestic birds and poultry each winter. To understand the role of wild birds in introducing these viruses in Japan, a phylodynamic analysis based on geography and host species was conducted using H5N1 isolates in Japan from 2021 to 2025. A total of 892 hemagglutinin gene sequences of H5N1 viruses, collected from birds between June 2021 and May 2025, along with additional sequences that were highly similar to those of Japanese isolates, were obtained from a public database. The role of wild birds in the transmission dynamics of H5N1 isolates in Japan across four winter seasons (2021-25) was assessed using a Bayesian phylodynamic approach with a Multi-Type Birth-Death model. Phylodynamic analysis revealed that the clade 2.3.4.4b comprised three distinct subgroups, G2b, G2c, and G2d, which were prevalent during the winter seasons. Isolates from G2b and G2c were linked to common ancestral strains from North Asia and Northeast Asia, respectively. Meanwhile, G2d, the dominant strain in Japan from 2021 to 2025, shared an ancestral strain from the Northwest America. During winters 2023-25, the ancestral strain was traced back to Northeast Asia, indicating a shift in the viral origin. This transition suggests an increase in virus migration events and expansion of host diversity, implying that Japan may function as a hub for intercontinental virus introductions, receiving multiple independent viral entries from North Asia, Northeast Asia, and Northwest America. Additionally, waterfowl and raptors played a role in introducing viruses into Japan, while poultry and crows generally serving as dead-end hosts. However, the continuous introduction of H5N1 isolates into Japan each winter can alter the disease transmission pattern observed in crows, resulting in more virus spillover from crows to other hosts, such as poultry and charadriiformes. These findings emphasize the importance of continuous monitoring and prompt information sharing to understand the global dynamics of viruses better.
• Risk analysis of infectious disease in pigs in Gifu prefecture, Japan, through network analysis.
  Naotoshi Kuninaga; Emi Yoshita; Miki Koyasu; Hibiki Morimoto; Noboru Hayashi; Takahiro Hiono; Satoshi Ito; Yoshihiro Sakoda; Norikazu Isoda
  Preventive veterinary medicine, 245, 106687, 106687, 2025年12月, ［国際誌］
  英語, 研究論文（学術雑誌）, Movements of livestock, humans, vehicles and wildlife are recognized as critical contributors to the spread of infectious diseases in livestock and can be modeled as a network to assess and predict disease transmission. This study developed a comprehensive multilayer network incorporating the movements of pigs, humans, vehicles, and, presumably, wild boars to estimate the risks of disease introduction and transmission for each husbandry stakeholder and to identify key clusters and modes of movement involved. A questionnaire-based study was conducted across 22 pig farms in Gifu Prefecture, Japan, collecting data on pig, human, and vehicle movements to establish networks. The wild boar movement network was estimated using data on pig farm locations and wild boar habitats collected from vegetation cover data. Movement-associated effects in each network based on movement frequency were assigned to combinations of the four networks, resulting in a four-layered network. The network exhibited small-world characteristics and was clustered into four groups. Disease containment schemes in livestock are commonly established along administrative boundaries, however these four epidemiological clusters, comprising 31, 28, 24, and 22 nodes, did not align exactly with administrative districts, suggesting the significance of managing livestock infectious diseases beyond governmental borders. In the Partial Least Squares Regression (PLSR) analysis, pig, vehicle, and wild boar movement made comparable positive contributions to PageRank-based node importance within the multilayer network. This study highlights the significance of epidemiological links among husbandry and nonhusbandry stakeholders, emphasizing the need to develop effective risk management tools considering the probable disease transmission pathways.
• Genetic Diversity of Highly Pathogenic Avian Influenza Viruses Isolated in Hokkaido, Japan, During Winter 2024-2025.
  Norikazu Isoda; Lim Yik Hew; Kazuki Nishikawa; Fumihito Takaya; Yo Shimazu; Daiki Kobayashi; Kei Nabeshima; Hisako Honjyo; Mana Esaki; Kosuke Okuya; Kosuke Soda; Hiroshi Ito; Asuka Kumagai; Hayate Nishiura; Takahiro Hiono; Hiroki Takakuwa; Tatsufumi Usui; Makoto Ozawa; Yuko Uchida; Manabu Onuma; Yoshihiro Sakoda
  Pathogens (Basel, Switzerland), 14, 9, 2025年09月21日, ［国際誌］
  英語, 研究論文（学術雑誌）, Genetic and antigenic analyses were performed on highly pathogenic avian influenza viruses (HPAIVs) isolated in Hokkaido, northern Japan, during the winter of 2024-2025. Ninety-eight HPAIVs were isolated from feces of waterfowl, tracheal swabs from dead wild birds, or lung homogenates from dead chickens. Phylogenetic analysis of the hemagglutinin (HA) gene from 47 representative isolates revealed that all sequences belonged to the G2d subgroup of clade 2.3.4.4b H5HA, which has been the dominant lineage in Hokkaido since the winter of 2021-2022. These isolates were further divided into three major groups within the subgroup. The HPAIVs isolated in the Republic of Korea, China, and North America were genetically closely related to the Hokkaido isolates, whereas no HPAIVs genetically related to European strains or those detected in North American cattle were identified. Furthermore, HPAIVs isolated from seabirds were genetically closely related to those found in dead marine mammals along the eastern coast of Hokkaido in the spring of 2025. No apparent antigenic differences were observed between the HPAIVs isolated in this study and those from previous seasons. These findings highlight the wide distribution of HPAIVs in Hokkaido, particularly from Asian and North American lineages, and underscore the importance of continuous surveillance.
• Dynamics of high pathogenicity avian influenza virus infection with multiple introductions in a crow flock in an urban park in Hokkaido, Japan.
  Norikazu Isoda; Takahiro Hiono; Yik Lim Hew; Fumihito Takaya; Bao Linh Nguyen; Daiki Kobayashi; Kaien Fujino; Yoshihiro Sakoda
  Comparative immunology, microbiology and infectious diseases, 121, 102367, 102367, 2025年08月, ［国際誌］
  英語, 研究論文（学術雑誌）, Since 2021, high pathogenicity avian influenza viruses (HPAIVs) of the H5N1 clade 2.3.4.4b has been circulating globally, not only in domestic poultry but also in wild birds, both migratory and resident species. In March to May 2022, March to April 2023, and January to April 2024, crow die-offs were reported in an urban garden in Hokkaido, Japan, raising suspicions of HPAIV infection. Since August 2022, all dead carcasses were investigated for HPAIV detection and isolation. Phylogenetic analysis of the H5 hemagglutinin gene revealed that all detected HPAIVs belonged to clade 2.3.4.4b, a dominant lineage in Hokkaido since early 2022. Two distinct subgroups were identified: G2d (in 2022-2024) and G2a (in 2024). A maximum clade credibility tree, based on concatenated nucleotide sequences of the isolates, suggested that multiple distinct types of HPAIVs were introduced into the garden in rotation during the winters of 2022-2023 and 2023-2024. Infectious HPAIVs were isolated not only from the lungs and brains but also from the rectal contents of the dead crows, with no apparent difference in viral titers between the two subgroups. The case reproduction numbers of HPAIV infection in the crow flock ranged from 0.52 and 1.57 in the spring of 2022 and from 0.55 to 1.78 in the spring of 2023, suggesting that the contiguous HPAIV infections in the crows were due to multiple introductions into the flock. Crow can play a key role of potential spread to other animals, poultry and wildlife in urban areas or humans in rural areas.
• Enhanced sulfate pseudo-affinity chromatography using monolith-like particle architecture for purifying SARS-CoV-2.
  Kenji Kadoi; Junya Toba; Ayana Uehara; Norikazu Isoda; Yoshihiro Sakoda; Eri Iwamoto
  Vaccine, 53, 126951, 126951, 2025年03月03日, ［国際誌］
  英語, 研究論文（学術雑誌）, Traditional virus chromatographic purification face limitations owing to the small pore sizes of conventional resins, which restrict efficient virus binding. The newly developed MLP1000 DexS, a cellulose monolith-like particle (MLP) with large continuous pores (radius of 1.5 μm) and a sulfate pseudo-affinity ligand, facilitates virus access to intraparticle surfaces and significantly enhances binding capacity. In this study, we investigated the effectiveness of MLP1000 DexS for purifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from Vero cells. Using a 0.29 mL column volume, we evaluated this resin through bind-elute mode chromatography under two load volume conditions (4.5 mL and 21 mL). MLP1000 DexS exhibited superior performance under high-loading conditions, achieving a high elution recovery of 59 % for the virus compared with that of 11-17 % for the commercial resins Cellufine Sulfate and Capto DeVirS. Additionally, the dsDNA removal capacity of MLP1000 DexS was 3.0-5.3-fold higher than that of the other resins. These findings suggest that MLP1000 DexS is an effective purification material for the downstream processing of live-attenuated and inactivated coronavirus vaccine production.
• Altered receptor-binding specificity of gull-adapted H13 avian influenza viruses corresponds to their unique host preferences.
  Rio Harada; Takahiro Hiono; Manabu Igarashi; Daiki Kobayashi; Hinako Ban; Norikazu Isoda; Yoshihiro Sakoda
  Virology, 605, 110460, 110460, 2025年02月21日, ［国際誌］
  英語, 研究論文（学術雑誌）, Avian influenza viruses (AIVs) recognize α2-3 sialosides as receptors. Previous studies showed that the structural diversity within α2-3 sialosides is related to the host specificity of AIVs. H13 AIVs are primarily isolated from gulls, although almost all AIV subtypes have been isolated from ducks, the natural hosts of AIVs. To elucidate the molecular basis of the host specificity of H13 viruses to gulls, the receptor-binding specificity of H13 hemagglutinins (HAs) and the distribution of viral receptors in gulls were investigated. The results revealed that recombinant HA (rHA) of H13 viruses had a binding preference for fucosylated α2-3 sialosides, which were distributed widely in the respiratory tract and intestines of gulls but not in the colon of ducks. Moreover, the receptor-binding specificity of mutant rHAs revealed that amino acids in the 130-loop and at position 227 of H13 HA were critical for the preference for fucosylated α2-3 sialosides. The results of the present study suggest that the binding specificity of H13 HA to fucosylated α2-3 sialosides is a key factor for the host susceptibility of H13 viruses to gulls.
• Deglycosylation and truncation in the neuraminidase stalk are functionally equivalent in enhancing the pathogenicity of a high pathogenicity avian influenza virus in chickens.
  Daiki Kobayashi; Takahiro Hiono; Hiromu Arakawa; Hiroyuki Kaji; Ayako Ohkawara; Takaya Ichikawa; Hinako Ban; Norikazu Isoda; Yoshihiro Sakoda
  Journal of virology, e0147824, 2025年02月14日, ［国際誌］
  英語, 研究論文（学術雑誌）, Influenza A viruses with fewer amino acids in the neuraminidase (NA) stalk domain are primarily isolated from chickens rather than wild ducks, indicating that a shortened NA stalk is considered an adaptation marker of avian influenza viruses (AIVs) to chickens. Experimental passages of an H7N7 nonpathogenic AIV (rgVac2-P0) in chickens resulted in a highly pathogenic variant (Vac2-P3L4) with a 34-amino-acid deletion in the NA stalk, encompassing five potential N-glycosylation sites. To investigate how amino acid truncation and deglycosylation in the NA stalk contribute to increased pathogenicity, a virus with glycosylation-deficient mutations at these sites (rgVac2-P3L4/P0NAΔGlyco) was constructed. Contrary to expectations, chickens inoculated with rgVac2-P3L4/P0NAΔGlyco exhibited variable clinical outcomes, attributed to the genetic instability of the virus. A single mutation stabilized the virus, and the mutant (rgVac2-P3L4/P0NAΔGlyco-Y65H) resulted in higher pathogenicity compared with a virus with restored glycosylation (rgVac2-P3L4/P0NA-Y65H). Glycan occupancy analysis revealed 3-4 glycans at the five potential sites. In functional analysis, glycosylation-deficient mutants, similar to the short-stalk NA virus, showed significantly reduced erythrocyte elution activity. Additionally, mutational analysis indicated variable contributions of N-glycans to elution activity across the sites. Moreover, the functionally most contributing sites of the five potential N-glycosylation motifs were consistently included in the amino acid deletions of the stalk-truncated NA in N7-subtyped field isolates, despite the varying truncation position or length. These findings suggest that the loss of glycosylation is functionally equivalent to a reduction in amino acids, and it plays a crucial role in enhancing pathogenicity in chickens and affecting NA function.IMPORTANCEAvian influenza poses significant economic challenges to the poultry industry and presents potential risks to human health. Understanding the molecular mechanisms that facilitate the emergence of chicken-adapted avian influenza viruses (AIVs) from non-pathogenic duck-origin influenza viruses is crucial for improving AIV monitoring systems in poultry and controlling this disease. Amino acid deletions in the neuraminidase (NA) stalk domain serve as one of the molecular markers for AIV adaptation to Galliformes. This study highlights the critical role of N-glycosylation in the NA stalk domain in the pathogenesis of high pathogenicity avian influenza viruses in chickens. The findings propose a novel theory that the loss of glycosylation at the NA stalk domain, rather than a reduction in stalk length, is responsible for both NA function and increased virus pathogenicity in chickens.
• Generation of Vaccine Candidate Strains That Antigenically Match Classical Swine Fever Virus Field Strains.
  Maya Kobayashi; Loc Tan Huynh; Saho Ogino; Lim Yik Hew; Miki Koyasu; Hikaru Kamata; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  Vaccines, 13, 2, 2025年02月14日, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Classical swine fever virus (CSFV) is genetically categorized into three genotypes. A live-attenuated vaccine strain GPE-, currently used in Japan, belongs to genotype 1 and is genetically distinct from the field strains circulating in Japan, which belong to genotype 2. This study aimed to understand the antigenicity of recent field isolates in Japan and develop new vaccine candidates that antigenically match field strains. METHODS: The serum samples of 20 pigs vaccinated with GPE- were subjected to a serum neutralizing test (SNT) using one of the field strains, CSFV/wb/Jpn-Mie/P96/2019 (Mie/2019). For the antigenic matching, vGPE-/HiBiT/Mie E2 was generated by replacing the viral glycoprotein E2, the main target of the neutralizing antibody, with that of Mie/2019. Additionally, vGPE-/HiBiT/Mie E2/PAPeV Erns was generated by further substituting glycoprotein Erns with that of pronghorn antelope pestivirus (PAPeV) since Erns is not important as a vaccine immunogen and can be replaced by that of other pestiviruses to provide an immunological marker. The efficacy of vGPE-/HiBiT/Mie E2/PAPeV Erns was further evaluated by the challenge experiments in pigs. RESULTS: The SNT titers of serum sample against Mie/2019 were 6.1-fold lower than that against vGPE-. The generated recombinant viruses showed closer antigenicity to Mie/2019 than vGPE-. The challenge study confirmed that vGPE-/HiBiT/Mie E2/PAPeV Erns provided clinical and virological protection against a field CSFV equivalent to vGPE-. CONCLUSIONS: This study demonstrated that swapping the E2 encoding region with the prevalent field CSFVs is a promising strategy to achieve antigenic matching between the vaccine and field strains.
• Serosurvey of Bovine Viral Diarrhea Virus in Cattle in Southern Japan and Estimation of Its Transmissibility by Transient Infection in Nonvaccinated Cattle.
  Norikazu Isoda; Satoshi Sekiguchi; Chika Ryu; Kosuke Notsu; Maya Kobayashi; Karin Hamaguchi; Takahiro Hiono; Yuichi Ushitani; Yoshihiro Sakoda
  Viruses, 17, 1, 2025年01月02日, ［国際誌］
  英語, 研究論文（学術雑誌）, Bovine viral diarrhea (BVD) is caused by the BVD virus (BVDV) and has been reported worldwide in cattle. To estimate BVDV circulation among cattle where few BVD cases were reported in southern Japan, 1910 serum samples collected from 35 cattle farms without a BVD outbreak were investigated to detect antibodies against BVDV-1 and BVDV-2 using an indicator virus with a cytopathogenic effect and the luciferase gene, respectively. Neutralizing antibodies against BVDV-1 and BVDV-2 were detected more frequently in 18 vaccinated farms than in 17 nonvaccinated farms. In the nonvaccinated farms, 9.6%, 1.8%, and 13.8% of the cattle were estimated to have a history of infection with BVDV-1, BVDV-2, and both, respectively. The median rate of within-herd anti-BVDV-1 seropositivity among cattle in the nonvaccinated farms was 22.0%; however, a high within-herd seropositivity (>50%) was confirmed in the two farms. The force of infection, basic reproduction number, and annual probability of BVDV-1 infection were estimated as 0.072 (95% confidence interval [CI]: 0.062-0.084), 0.36 (95% CI: 0.31-0.42), and 0.73% (95% CI: 0.61-0.87%), respectively, using the age-specific positive rate of anti-BVDV-1 antibodies. These parameters should be further applicable for developing epidemiological models which illustrate the BVDV dynamics in the field.
• Risk Mapping of African Swine Fever in Domestic Pigs and Wild Boars to Enhance Management and Surveillance in Asia.
  Nijiho Kawaguchi; Cecilia Aguilar-Vega; Michihito Sasaki; Yasuko Orba; Hirofumi Sawa; José Manuel Sánchez-Vizcaíno; Norikazu Isoda; Jaime Bosch; Satoshi Ito
  Transboundary and emerging diseases, 2025, 8850856, 8850856, 2025年, ［国際誌］
  英語, 研究論文（学術雑誌）, African swine fever (ASF) is a highly lethal disease affecting domestic pigs and wild boars, caused by the ASF virus (ASFV), which has rapidly spread across Asia in recent years. In this region, most reported ASF cases involve domestic pigs, while cases in wild boars remain notably lower except in a few countries. However, factors such as the high population of wild boars, limited wildlife surveillance, and inadequate farm biosecurity suggest that the prevalence and transmission of ASFV between these hosts may be underestimated. Therefore, we used a simplified multicriteria approach (SMCA) to identify vulnerable areas (VAs) for ASFV infection and validated the resulting VA maps with chi-square tests using reported ASF cases. The spatial SMCA revealed that VAs for ASFV infection in domestic pigs are concentrated in eastern China, while high-risk zones for ASFV infection in wild boars span Russia, eastern China, and Southeast Asia. Sensitity analysis showed that the variables that most influenced the risk of ASFV infection in domestic pigs and wild boars were anthropogenic factors and distribution of wild boars, respectively. Additionally, we predicted areas with significant transmission potential between domestic pigs and wild boars. High-risk regions for interspecies transmission include eastern China, southwestern Korea, and southern Japan. This study offers a standardized method to assess ASFV infection risk across Asia by integrating environmental and anthropogenic factors rather than relying solely on reported outbreaks. The findings highlight potential high-risk regions, including those without detected outbreaks, to improve surveillance and early detection strategies.
• Optimizing Oral Vaccine Distribution Strategies for Wild Boars Through Bias‐Corrected Habitat Modeling: A Case Study of Classical Swine Fever Control in Japan
  Satoshi Ito; Jamie Bosch; Cecilia Aguilar-Vega; Norikazu Isoda; José Manuel Sánchez-Vizcaíno; Masuo Sueyoshi
  Transboundary and Emerging Diseases, 2025, 1, Wiley, 2025年01月
  研究論文（学術雑誌）, Control of infectious diseases in wildlife is often considered challenging due to the limited availability of information. Some infectious diseases in wildlife can also affect livestock, posing significant problems for the animal farming industry. In Japan, classical swine fever (CSF) reemerged in September 2018. Given the availability of commercial vaccines, control measures mainly involve the vaccination of domestic pigs and the distribution of oral vaccines to wild boars. Despite these efforts, the disease continues to spread, primarily due to wild boars. This transmission is further exacerbated by Japan’s challenging geography—about 66% forested—making many areas difficult to access and leading to spatial bias in surveillance. As a result, the epidemic situation cannot be fully understood, limiting the effectiveness of control measures. This study estimated wild boar distribution using a species distribution model (SDM) that incorporates geographic bias correction. Two maximum entropy (MaxEnt) models—a standard model and a reporting bias‐corrected model—were developed using wild boar observation data from Aichi Prefecture. Both models demonstrated excellent prediction accuracy (area under the curve [AUC] of 0.946 and 0.946, sensitivity of 0.868 and 0.943, and specificity of 0.999 and 0.991), with the most influential variables identified in a similar order (solar radiation in November, followed by elevation, precipitation during the wettest quarter, and solar radiation in August). While both models identified high‐probability areas in the east, the bias‐corrected model also revealed expanded high‐probability zones in the northeast. During the epidemic phases, protecting farms takes priority; however, in eradication phases, control measures must also target wild boar habitats in forested areas. By using open‐access environmental data, this modeling approach can be applied to other regions. Accurate estimation of wild boar distribution can contribute to improving wildlife disease surveillance and optimizing oral vaccine delivery strategies.
• Direct TaqMan assay for the detection and genotyping of bovine viral diarrhea virus types 1 and 2
  Shakir Ullah; Kosuke Notsu; Akatsuki Saito; Tamaki Okabayashi; Hirohisa Mekata; Norikazu Isoda; Satoshi Sekiguchi
  Archives of Virology, 170, 1, Springer Science and Business Media LLC, 2024年12月12日
  研究論文（学術雑誌）, Abstract
  
  Bovine viral diarrhea (BVD), caused by bovine viral diarrhea virus (BVDV), has a significant economic impact on affected farms worldwide. For effective disease control, it is crucial to select an appropriate vaccine based on the specific genotype of BVDV. Therefore, developing a rapid and reliable assay to detect and genotype BVDV is imperative for controlling the spread of disease. In this study, we developed a TaqMan assay to detect and genotype BVDV types 1 and 2 directly in bovine serum without extraction of RNA. The direct BVDV TaqMan assay effectively detected both BVDV1 and BVDV2 with confirmed specificity and showed no cross-reactivity with any of the other viruses tested, including bovine respiratory syncytial virus, bovine coronavirus, Akabane virus, bovine herpesvirus 1, bovine parainfluenza virus 3, bovine immunodeficiency virus, and bovine leukemia virus. The assay could detect the virus in serum samples with a titer as low as 10² TCID₅₀/mL in two out of three trials for BVDV1 and all three trials for BVDV2, indicating that its sensitivity is equivalent to that of virus isolation. Our findings represent a significant advancement in BVDV detection and typing directly from bovine serum.
• Cocirculation of Genetically Distinct Highly Pathogenic Avian Influenza H5N5 and H5N1 Viruses in Crows, Hokkaido, Japan.
  Yik Lim Hew; Takahiro Hiono; Isabella Monne; Kei Nabeshima; Saki Sakuma; Asuka Kumagai; Shunya Okamura; Kosuke Soda; Hiroshi Ito; Mana Esaki; Kosuke Okuya; Makoto Ozawa; Toshiyo Yabuta; Hiroki Takakuwa; Linh Bao Nguyen; Norikazu Isoda; Kohtaro Miyazawa; Manabu Onuma; Yoshihiro Sakoda
  Emerging infectious diseases, 30, 9, 1912, 1917, 2024年09月, ［国際誌］
  英語, 研究論文（学術雑誌）, We isolated highly pathogenic avian influenza (HPAI) H5N5 and H5N1 viruses from crows in Hokkaido, Japan, during winter 2023-24. They shared genetic similarity with HPAI H5N5 viruses from northern Europe but differed from those in Asia. Continuous monitoring and rapid information sharing between countries are needed to prevent HPAI virus transmission.
• Evaluation of Immune Status of Pigs against Classical Swine Fever for Three Years after the Initiation of Vaccination in Gifu Prefecture, Japan.
  Keisuke Kuwata; Naotoshi Kuninaga; Yoko Kimura; Kohei Makita; Norikazu Isoda; Yukio Shimizu; Yoshihiro Sakoda
  Pathogens (Basel, Switzerland), 13, 8, 2024年07月25日, ［国際誌］
  英語, 研究論文（学術雑誌）, In 2018, classical swine fever (CSF) reemerged in Gifu Prefecture, Japan, after 26 years of absence, and vaccination of domestic pigs using a live attenuated vaccine was initiated in 2019. Because the vaccine efficacy in piglets is influenced by the maternal antibody levels, vaccination should be administered at the optimal age by assuming the antibody level in sows. In this study, the shift in the antibody titer distribution in sows due to the initiation of vaccination to naïve herds and its influence on the vaccine-induced immunity rate in fattening pigs were investigated for 3 years. The results indicated that higher antibody titers were induced in first-generation sows after vaccine initiation because they were immunologically naïve, but the distribution of antibody titers shifted to lower levels along with their replacement with second-generation sows. The average vaccination age of fattening pigs became earlier year by year, and the vaccine-induced antibody rate was almost ≥80%. Based on the estimation of the optimal age for vaccination, it was found that vaccination at a younger age may reduce the risk of CSF infection. Taken together, the risk of CSF outbreaks can be reduced by administering vaccines at the optimal age based on the sequential monitoring of the sow's immune status.
• Assessment of the Safety Profile of Chimeric Marker Vaccine against Classical Swine Fever: Reversion to Virulence Study.
  Loc Tan Huynh; Mikihiro Otsuka; Maya Kobayashi; Hung Dinh Ngo; Lim Yik Hew; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  Viruses, 16, 7, 2024年07月12日, ［国際誌］
  英語, 研究論文（学術雑誌）, Chimeric marker vaccine candidates, vGPE-/PAPeV Erns and vGPE-/PhoPeV Erns, have been generated and their efficacy and capability to differentiate infected from vaccinated animals were confirmed in previous studies. The safety profile of the two chimeric marker vaccine candidates, particularly in the potential reversion to virulence, was evaluated. Each virus was administered to pigs with a dose equivalent to the vaccination dose, and pooled tonsil homogenates were subsequently inoculated into further pigs. Chimeric virus vGPE-/PAPeV Erns displayed the most substantial attenuation, achieving this within only two passages, whereas vGPE-/PhoPeV Erns was detectable until the third passage and disappeared entirely by the fourth passage. The vGPE- strain, assessed alongside, consistently exhibited stable virus recovery across each passage without any signs of increased virulence in pigs. In vitro assays revealed that the type I interferon-inducing capacity of vGPE-/PAPeV Erns was significantly higher than that of vGPE-/PhoPeV Erns and vGPE-. In conclusion, the safety profile of the two chimeric marker vaccine candidates was affirmed. Further research is essential to ensure the stability of their attenuation and safety in diverse pig populations.
• Development of a dual immunochromatographic test strip to detect E2 and Erns antibodies against classical swine fever
  Loc Tan Huynh; Eun-Ju Sohn; Youngmin Park; Juhun Kim; Tomohiko Shimoda; Takahiro Hiono; Norikazu Isoda; Sung-Hee Hong; Ha-Na Lee; Yoshihiro Sakoda
  Frontiers in Microbiology, 15, Frontiers Media SA, 2024年04月11日
  研究論文（学術雑誌）, Background
  
  It is essential to consider a practical antibody test to successfully implement marker vaccines and validate vaccination efficacy against classical swine fever virus (CSFV). The test should include a serological antibody assay, combined with a tool for differentiating infected from vaccinated animals (DIVA). The immunochromatographic test strip (ICS) has been exclusively designed for detecting CSFV E2 antibodies while lacking in detecting E^rns antibodies, which can be employed and satisfy DIVA strategy. This study developed a novel ICS for detecting CSFV E2/E^rns dual-antibody. The effectiveness of ICS in evaluating the DIVA capability of two novel chimeric pestivirus vaccine candidates was assessed.
  
  Methods
  
  Recombinant E2 or E^rns protein was transiently expressed in the plant benthamiana using Agrobacterium tumefaciens. ICS was subsequently assembled, and goat anti-rabbit IgG and recombinant CSFV E2 or E^rns protein were plated onto the nitrocellulose membrane as control and test lines, respectively. The sensitivity and specificity of ICS were evaluated using sera with different neutralizing antibody titers or positive for antibodies against CSFV and other pestiviruses. The coincidence rates for detecting E2 and E^rns antibodies between ICS and commercial enzyme-linked immunosorbent assay (ELISA) kits were also computed. ICS performance for DIVA capability was evaluated using sera from pigs vaccinated with conventional vaccine or chimeric vaccine candidates.
  
  Results
  
  E2 and E^rns proteins were successfully expressed in N. benthamiana-produced recombinant proteins. ICS demonstrated high sensitivity in identifying CSFV E2 and E^rns antibodies, even at the low neutralizing antibody titers. No cross-reactivity with antibodies from other pestiviruses was confirmed using ICS. There were high agreement rates of 93.0 and 96.5% between ICS and two commercial ELISA kits for E2 antibody testing. ICS also achieved strong coincidence rates of 92.9 and 89.3% with two ELISA kits for E^rns antibody detection. ICS confirmed the absence of CSFV E^rns-specific antibodies in sera from pigs vaccinated with chimeric vaccine candidates.
  
  Conclusion
  
  E2 and E^rns proteins derived from the plant showed great potential and can be used to engineer a CSFV E2/E^rns dual-antibody ICS. The ICS was also highly sensitive and specific for detecting CSFV E2 and E^rns antibodies. Significantly, ICS can fulfill the DIVA concept by incorporating chimeric vaccine candidates.
• Continuous Introduction of H5 High Pathogenicity Avian Influenza Viruses in Hokkaido, Japan: Characterization of Viruses Isolated in Winter 2022–2023 and Early Winter 2023–2024
  Lim Yik Hew; Norikazu Isoda; Fumihito Takaya; Kohei Ogasawara; Daiki Kobayashi; Loc Tan Huynh; Tatsuru Morita; Rio Harada; Nikolay Gennadievich Zinyakov; Dmitriy Borisovich Andreychuk; Ilya Alexandrovich Chvala; Viktor Nikolaevich Irza; Yukiko Watanabe; Hiroko Fujita; Keisuke Saito; Takahiro Hiono; Yoshihiro Sakoda
  Transboundary and Emerging Diseases, 2024, 1, 18, Hindawi Limited, 2024年03月14日
  研究論文（学術雑誌）, High pathogenicity avian influenza (HPAI) has impacted poultry and wild birds globally. The number of H5 HPAI virus (HPAIV) infection cases in wild birds in Hokkaido (Northern Japan) was high in the last two seasons, contributing to virus spillover to resident birds and poultry. Therefore, H5 HPAIVs in birds and mammals in Hokkaido in winter 2022–2023 and 2023–2024 were monitored and viruses were phylogenetically, antigenically, and pathogenetically characterized. Thirty HPAIV isolates were subtyped and pathotyped by sequencing the hemagglutinin (HA) gene of viruses. Phylogenetic analysis of the HA gene revealed that all isolated HPAIVs were categorized into clade 2.3.4.4b and divided into three groups (G2b, G2c, and G2d). Most isolates belonging to subgroup G2d clustered with isolates in winter 2021–2022 in Hokkaido. The other isolates were categorized into two subgroups, G2b and G2c, mainly composed of isolates in Honshu Island in winter 2021–2022 and 2022–2023, respectively. Two H5 HPAIVs isolated in Eastern Russia in spring and autumn 2022 were genetically close to most Hokkaido isolates (G2d), and a virus isolated in Hokkaido in November 2023 was also grouped in subgroup G2d. Further analysis of all eight gene segments identified six types of gene constellations. Cross-hemagglutination inhibition test indicated that the antigenicity of H5 HPAIVs isolated in the last several seasons was similar within them but slightly different from that in the 2010s. Three chicken breeds were intranasally challenged with four representative isolates to assess their pathogenicity. All chickens except one broiler chicken were dead until 5-day postchallenge with different pathogenicity of these viruses. The pathogenicity of one HPAIV strain was significantly lower in broiler chickens than in layer chickens. The mixture of multiple characteristics of HPAIVs in Hokkaido was confirmed by bird migration routes. Thus, many HPAIVs can be brought and scattered anywhere on Earth.
• Editorial: Epidemiology of the transboundary swine diseases in Asia & Pacific
  Satoshi Ito; Jaime Bosch; Norikazu Isoda; Lam Thanh Nguyen; Marta Martinez Aviles
  Frontiers in Veterinary Science, 11, Frontiers Media SA, 2024年02月20日
  研究論文（学術雑誌）
• [The current situation of H5 high pathogenicity avian influenza viruses in wild birds and mammals].
  Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  Uirusu, 74, 2, 107, 116, 2024年, ［国内誌］
  日本語, 研究論文（学術雑誌）, H5 high pathogenicity avian influenza viruses, which emerged in Guangdong Province, China, in 1996, has now been persistently transmitted among various wild birds due to the "silent spreading" of the viruses among vaccinated poultry and domestic waterfowl. These viruses traveled long distances along with bird migration; therefore, the threat of H5 high pathogenicity avian influenza viruses is now a global issue. Furthermore, infection in wild mammals has become more prominent since 2020. The contamination of the wild bird population by the virus is considered to be an irreversible situation, and thus, the reduction of virus levels in the environment is an urgent issue to prevent further deterioration of the situation. This review will describe the history and current situations of influenza virus infection in wild birds and mammals, and discuss the research and countermeasures that are required to stop the damage caused by this virus.
• Identifying Effective Biosecurity Measures for Preventing the Introduction of Classical Swine Fever in Pig Farms in Japan: Under the Condition of Absence/Presence of Observable Infected Wild Boar
  Makoto Ukita; Ryota Matsuyama; Norikazu Isoda; Ryosuke Omori; Takehisa Yamamoto; Kohei Makita
  Transboundary and Emerging Diseases, 2024, 1, Wiley, 2024年01月, ［査読有り］
  研究論文（学術雑誌）, The outbreak of infectious diseases in swine, such as classical swine fever (CSF), has become a significant concern in the pig‐farming industry. In Japan, after the re‐emergence of CSF in 2018, farms are now exposed to the risk of transmission from infected wild boar and CSF‐contaminated farms. This study aimed to identify biosecurity measures that were effective for the prevention of CSF introduction into farms during the period from the beginning of the CSF epidemic to the implementation of a vaccination campaign for domestic pigs at risk. The probability of virus introduction was assumed to be increased by the elevated risk from CSF‐infected wild boar and infected farms around the farm. The risk from infected wild boar was represented by the prevalence of CSF in wild boar or the occupancy of 1‐km grid cells with infected wild boar within 10‐km radii from a pig farm and the occurrence of CSF outbreaks on neighboring farms. Conversely, the probability of virus introduction was assumed to decrease in response to on‐farm biosecurity measures being implemented on each farm. The implementation of biosecurity measures on the farms and farm attributes were obtained through a questionnaire survey. Analyses were performed on each farm under the weekly situations where infected wild boar were both absent and present in the vicinity using a binomial generalized linear model. On farms where infected wild boar were not present around farms, daily washing and disinfecting of work clothing in pig houses was identified as the main measure to reduce the risk of CSF introduction into farms. On farms with infected wild boar in the vicinity, the absence of public roads on the farm and preventing wildlife intrusion into the areas where pig carcasses were stored were demonstrated to be effective in preventing CSF introduction. Based on the assumption that strict and comprehensive biosecurity measures are required to prevent CSF introduction, the implementation of these potentially effective measures is worth being prioritized.
• Establishment of a superinfection exclusion method for pestivirus titration using a recombinant reporter pestiviruses
  Yume MIMURA; Takahiro HIONO; Loc Tan HUYNH; Saho OGINO; Maya KOBAYASHI; Norikazu ISODA; Yoshihiro SAKODA
  Journal of Veterinary Medical Science, Japanese Society of Veterinary Science, 2024年
  研究論文（学術雑誌）
• 高病原性鳥インフルエンザウイルス感染の治療を目指したヒト用抗インフルエンザ薬のユーラシアワシミミズクへの投与試験
  島津 陽; 尾原 涼; 西村 享平; 三木 万梨子; 佐渡 晃浩; 境 秀文; 磯田 典和; 日尾野 隆大; 宍戸 貴雄; 齊藤 慶輔; 池中 良徳; 迫田 義博
  日本野生動物医学会誌, 28, Suppl., 164, 165, 日本野生動物医学会, 2023年12月
  日本語
• Exploring Appropriate Strategies for Vaccination against Classical Swine Fever under a Dynamic Change in Antibody Titer in Sows after Starting Vaccination in a Japanese Farm Setting
  Makoto Ukita; Keisuke Kuwata; Eiji Tanaka; Ryota Matsuyama; Norikazu Isoda; Yoshihiro Sakoda; Takehisa Yamamoto; Kohei Makita
  Transboundary and Emerging Diseases, 2023, 1, 15, Hindawi Limited, 2023年11月30日
  研究論文（学術雑誌）, After 26 years of absence in Japan, a classical swine fever (CSF) outbreak occurred at a domestic pig farm in 2018. Vaccination against the CSF virus with a live attenuated vaccine at pig farms was restarted in October 2019, which was 13 years after the 2006 ban on vaccination. An individual-based simulation model for CSF antibody dynamics was developed to determine an effective CSF vaccination strategy for pig populations. In creating a simulated pig herd, the optimal vaccination age of piglets and the effect of vaccinating piglets twice were evaluated. Additionally, the herd immunity was monitored every 6 months for 4 years after the start of vaccination, and the effects of intensive sow replacement policies were assessed. The simulation results indicated that the vaccination age should be delayed relative to the age used before the 2006 ban on vaccination and shifted earlier, from 8 weeks to 6 weeks, as time elapses. The simulations indicated a tradeoff in protection between the weaning period (i.e., maternally derived antibodies) and the fattening period (i.e., by vaccine-induced antibodies). Mixing sows with high and low antibody titers, particularly sows that received the first vaccination and those born after the start of vaccination, resulted in a high variation in antibody titer among pigs on the farm. This study also clarified the positive effect of intensive sow replacement strategies on shortening the period in which sows show diverse titers. Differences in sow replacement rates among farms and/or the time lag in starting vaccination in different prefectures result in heterogeneity in herd immunity in Japan; thus, herd immunity status should be examined at every farm using this simulation model.
• 組換えレポーターウイルスを用いたペスチウイルスの新しい感染価測定法の確立
  三村 優芽; Huynh Tan Loc; 小林 茉弥; 日尾野 隆大; 磯田 典和; 迫田 義博
  日本獣医学会学術集会講演要旨集, 166回, 128, 128, (公社)日本獣医学会, 2023年09月
  日本語
• 古典的ブタコレラマーカーワクチン用vGPE-由来キメラウイルスのレスキューと有効性(Rescue and efficacy of chimeric virus derived from vGPE- for classical swine fever marker vaccine)
  Huynh Tan Loc; Lim Hew Yik; 荻野 紗帆; 三村 優芽; 小林 茉弥; 金 琢洙; 日尾野 隆大; 磯田 典和; 迫田 義博
  日本獣医学会学術集会講演要旨集, 166回, 128, 128, (公社)日本獣医学会, 2023年09月
  英語
• H13亜型鳥インフルエンザウイルスはオオセグロカモメの呼吸器上皮に分布するフコシル化α2,3シアル酸糖鎖を認識する
  原田 里桜; 日尾野 隆大; 小林 大樹; 伴 日向子; 五十嵐 学; 磯田 典和; 迫田 義博
  日本獣医学会学術集会講演要旨集, 166回, 130, 130, (公社)日本獣医学会, 2023年09月
  日本語
• 牛ウイルス性下痢ウイルスの迅速な組換えウイルスの作出
  田村 友和; 荻野 紗帆; 日尾野 隆大; 鈴木 理滋; 鈴木 紗織; 磯田 典和; 迫田 義博; 福原 崇介
  日本獣医学会学術集会講演要旨集, 166回, 134, 134, (公社)日本獣医学会, 2023年09月
  日本語
• ネットワーク解析を用いた豚感染症リスクモデルの樹立とリスク管理法への応用
  吉田 恵実; 國永 尚稔; 子安 美紀; 森本 陽美記; 迫田 義博; 磯田 典和
  日本獣医学会学術集会講演要旨集, 166回, 219, 219, (公社)日本獣医学会, 2023年09月
  日本語
• Detection of H5N1 High Pathogenicity Avian Influenza Viruses in Four Raptors and Two Geese in Japan in the Fall of 2022.
  Kei Nabeshima; Yoshihiro Takadate; Kosuke Soda; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda; Junki Mine; Kohtaro Miyazawa; Manabu Onuma; Yuko Uchida
  Viruses, 15, 9, 2023年09月01日, ［国際誌］
  英語, 研究論文（学術雑誌）, In the fall of 2022, high pathogenicity avian influenza viruses (HPAIVs) were detected from raptors and geese in Japan, a month earlier than in past years, indicating a shift in detection patterns. In this study, we conducted a phylogenetic analysis on H5N1 HPAIVs detected from six wild birds during the 2022/2023 season to determine their genetic origins. Our findings revealed that these HPAIVs belong to the G2 group within clade 2.3.4.4b, with all isolates classified into three subgroups: G2b, G2d, and G2c. The genetic background of the G2b virus (a peregrine falcon-derived strain) and G2d viruses (two raptors and two geese-derived strains) were the same as those detected in Japan in the 2021/2022 season. Since no HPAI cases were reported in Japan during the summer of 2022, it is probable that migratory birds reintroduced the G2b and G2d viruses. Conversely, the G2c virus (a raptor-derived strain) was first recognized in Japan in the fall of 2022. This strain might share a common ancestor with HPAIVs from Asia and West Siberia observed in the 2021/2022 season. The early migration of waterfowl to Japan in the fall of 2022 could have facilitated the early invasion of HPAIVs.
• Generation and Efficacy of Two Chimeric Viruses Derived from GPE− Vaccine Strain as Classical Swine Fever Vaccine Candidates
  Loc Tan Huynh; Norikazu Isoda; Lim Yik Hew; Saho Ogino; Yume Mimura; Maya Kobayashi; Taksoo Kim; Tatsuya Nishi; Katsuhiko Fukai; Takahiro Hiono; Yoshihiro Sakoda
  Viruses, 15, 7, 1587, 1587, MDPI AG, 2023年07月20日
  研究論文（学術雑誌）, A previous study proved that vGPE− mainly maintains the properties of classical swine fever (CSF) virus, which is comparable to the GPE− vaccine seed and is a potentially valuable backbone for developing a CSF marker vaccine. Chimeric viruses were constructed based on an infectious cDNA clone derived from the live attenuated GPE− vaccine strain as novel CSF vaccine candidates that potentially meet the concept of differentiating infected from vaccinated animals (DIVA) by substituting the glycoprotein Erns of the GPE− vaccine strain with the corresponding region of non-CSF pestiviruses, either pronghorn antelope pestivirus (PAPeV) or Phocoena pestivirus (PhoPeV). High viral growth and genetic stability after serial passages of the chimeric viruses, namely vGPE−/PAPeV Erns and vGPE−/PhoPeV Erns, were confirmed in vitro. In vivo investigation revealed that two chimeric viruses had comparable immunogenicity and safety profiles to the vGPE− vaccine strain. Vaccination at a dose of 104.0 TCID50 with either vGPE−/PAPeV Erns or vGPE−/PhoPeV Erns conferred complete protection for pigs against the CSF virus challenge in the early stage of immunization. In conclusion, the characteristics of vGPE−/PAPeV Erns and vGPE−/PhoPeV Erns affirmed their properties, as the vGPE− vaccine strain, positioning them as ideal candidates for future development of a CSF marker vaccine.
• ネットワーク解析を用いた豚感染症リスク管理法の樹立
  吉田 恵実; 國永 尚稔; 子安 美紀; 森本 陽美記; 磯田 典和; 迫田 義博
  獣医疫学雑誌, 27, 1, 23, 24, 獣医疫学会, 2023年07月
  日本語
• ネットワーク解析を用いた岐阜県内養豚場における豚熱発生リスクの解析
  國永 尚稔; 吉田 恵実; 林 登; 磯田 典和; 迫田 義博
  獣医疫学雑誌, 27, 1, 25, 26, 獣医疫学会, 2023年07月
  日本語
• 2021-2022年冬季に国内で検出されたH5亜型高病原性鳥インフルエンザウイルスの性状と来シーズンの展望
  迫田 義博; 日尾野 隆大; 小林 大樹; Gulyaeva Marina; Shestopalov Alexander; 鍋島 圭; 本庄 比佐子; 横山 美沙子; 大沼 学; 磯田 典和
  日本野生動物医学会誌, 27, Suppl., 161, 161, 日本野生動物医学会, 2023年03月
  日本語
• 鳥類におけるバロキサビルマルボキシルの安全性の検討
  三木 万梨子; 尾原 涼; 西村 享平; 岡 良子; 宍戸 貴雄; 福島 民雄; 吉本 淳; 中山 翔太; 木村 亨史; 池中 良徳; 小笠原 浩平; 齊藤 慶輔; 日尾野 隆大; 磯田 典和; 迫田 義博
  日本野生動物医学会誌, 27, Suppl., 176, 177, 日本野生動物医学会, 2023年03月
  日本語
• 高病原性鳥インフルエンザウイルスに感染したオジロワシにおける,バロキサビルマルボキシルによる治療の試み
  齊藤 慶輔; 渡邊 有希子; 小笠原 浩平; 磯田 典和; 日尾野 隆大; 宍戸 貴雄; 西村 享平; 安達 光; 河野 晴子; 石井 千尋; 大沼 学; 迫田 義博
  日本野生動物医学会誌, 27, Suppl., 182, 182, 日本野生動物医学会, 2023年03月
  日本語
• Genetic, Antigenic, and Pathobiological Characterization of H9 and H6 Low Pathogenicity Avian Influenza Viruses Isolated in Vietnam from 2014 to 2018.
  Kien Trung Le; Lam Thanh Nguyen; Loc Tan Huynh; Duc-Huy Chu; Long Van Nguyen; Tien Ngoc Nguyen; Tien Ngoc Tien; Keita Matsuno; Masatoshi Okamatsu; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  Microorganisms, 11, 2, 2023年01月18日, ［国際誌］
  英語, 研究論文（学術雑誌）, The H9 and H6 subtypes of low pathogenicity avian influenza viruses (LPAIVs) cause substantial economic losses in poultry worldwide, including Vietnam. Herein, we characterized Vietnamese H9 and H6 LPAIVs to facilitate the control of avian influenza. The space-time representative viruses of each subtype were selected based on active surveillance from 2014 to 2018 in Vietnam. Phylogenetic analysis using hemagglutinin genes revealed that 54 H9 and 48 H6 Vietnamese LPAIVs were classified into the sublineages Y280/BJ94 and Group II, respectively. Gene constellation analysis indicated that 6 and 19 genotypes of the H9 and H6 subtypes, respectively, belonged to the representative viruses. The Vietnamese viruses are genetically related to the previous isolates and those in neighboring countries, indicating their circulation in poultry after being introduced into Vietnam. The antigenicity of these subtypes was different from that of viruses isolated from wild birds. Antigenicity was more conserved in the H9 viruses than in the H6 viruses. Furthermore, a representative H9 LPAIV exhibited systemic replication in chickens, which was enhanced by coinfection with avian pathogenic Escherichia coli O2. Although H9 and H6 were classified as LPAIVs, their characterization indicated that their silent spread might significantly affect the poultry industry.
• Susceptibility of common dabbling and diving duck species to clade 2.3.2.1 H5N1 high pathogenicity avian influenza virus: an experimental infection study
  Kosuke SODA; Yukiko TOMIOKA; Tatsufumi USUI; Hiroichi OZAKI; Hiroshi ITO; Yasuko NAGAI; Naoki YAMAMOTO; Masatoshi OKAMATSU; Norikazu ISODA; Masahiro KAJIHARA; Yoshihiro SAKODA; Ayato TAKADA; Toshihiro ITO
  Journal of Veterinary Medical Science, 85, 9, 942, 949, Japanese Society of Veterinary Science, 2023年
  研究論文（学術雑誌）
• Development of an Effective Oral Vaccine Dissemination Strategy against Classical Swine Fever for Wild Boar in Gifu Prefecture, Japan
  Satoshi Ito; Jaime Bosch; Cecilia Aguilar-Vega; Norikazu Isoda; Marta Martínez-Avilés; José Manuel Sánchez-Vizcaíno
  Transboundary and Emerging Diseases, 2023, 2023年
  研究論文（学術雑誌）
• Virological, pathological, and glycovirological investigations of an Ezo red fox and a tanuki naturally infected with H5N1 highly pathogenic avian influenza viruses in Hokkaido, Japan
  Takahiro Hiono; Daiki Kobayashi; Atsushi Kobayashi; Tamami Suzuki; Yuki Satake; Rio Harada; Keita Matsuno; Mariko Sashika; Hinako Ban; Maya Kobayashi; Keisuke Aoshima; Fumihito Takaya; Hiroko Fujita; Norikazu Isoda; Takashi Kimura; Yoshihiro Sakoda
  Virology, 578, 35, 44, 2023年01月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, In winter/spring 2021-2022, high pathogenicity avian influenza viruses (HPAIVs) that are genetically closely related to each other were detected worldwide. In a public garden in Sapporo, Hokkaido, Japan, a crow die-off by HPAIV infection occurred from March 29 to May 18, 2022. During the event, H5N1 HPAIVs were isolated from an Ezo red fox (Vulpes vulpes schrencki) and a tanuki (Nyctereutes procyonoides albus) found in the same garden. The fox showed viral meningoencephalitis and moderate virus replication in the upper respiratory tract, whereas the tanuki showed viral conjunctivitis and secondary bacterial infection in the eyes accompanied with visceral larva migrans. Viruses isolated from the fox and the tanuki were genetically closely related to those isolated from crows in the same garden. Various α2-3 sialosides were found in the respiratory tracts of these canid mammals, consistent with HPAIV infections in these animals. This study highlighted the importance of monitoring HPAIV infections in wild carnivore mammals to detect the potential virus spreading in nature.
• 北海道における野鳥および野生哺乳動物からのH5N1亜型高病原性鳥インフルエンザウイルスの検出事例について
  磯田 典和; 日尾野 隆大; 迫田 義博
  病原微生物検出情報月報, 43, 11, 259, 260, 国立感染症研究所, 2022年11月
  日本語
• Experimental and natural infections of white-tailed sea eagles (Haliaeetus albicilla) with high pathogenicity avian influenza virus of H5 subtype
  Yoshikazu Fujimoto; Kohei Ogasawara; Norikazu Isoda; Hitoshi Hatai; Kosuke Okuya; Yukiko Watanabe; Ayato Takada; Yoshihiro Sakoda; Keisuke Saito; Makoto Ozawa
  Frontiers in Microbiology, 13, Frontiers Media SA, 2022年10月03日
  研究論文（学術雑誌）, White-tailed sea eagle (Haliaeetus albicilla), a regionally rare species of raptor, is threatened in several countries. To assess the risk of H5 high pathogenicity avian influenza (HPAI) viral infection in rare bird species, we performed experimental infections with a GS/GD96-lineage H5N6 HPAI virus of clade 2.3.4.4e in white-tailed sea eagles. Additionally, during the winter of 2020–2021 in Japan, we accidentally encountered a white-tailed sea eagle that had a fatal outcome due to natural infection with a GS/GD96-lineage H5N8 HPAI virus of clade 2.3.4.4b, allowing us to compare experimental and natural infections in the same rare raptor species. Our experiments demonstrated the susceptibility of white-tailed sea eagles to the GS/GD96-lineage H5 HPAI virus with efficient replication in systemic organs. The potential for the viruses to spread within the white-tailed sea eagle population through indirect transmission was also confirmed. Comprehensive comparisons of both viral distribution and histopathological observations between experimentally and naturally infected white-tailed sea eagles imply that viral replication in the brain is responsible for the disease severity and mortality in this species. These findings provide novel insights into the risk assessment of H5 HPAI viral infection in white-tailed sea eagles, proper diagnostic procedures, potential risks to artificially fed eagle populations and persons handling superficially healthy eagles, potential impact of intragastric infection on eagle outcomes, and possibility of severity of the disease being attributed to viral replication in the brain.
• Detection of New H5N1 High Pathogenicity Avian Influenza Viruses in Winter 2021-2022 in the Far East, Which Are Genetically Close to Those in Europe.
  Norikazu Isoda; Manabu Onuma; Takahiro Hiono; Ivan Sobolev; Hew Yik Lim; Kei Nabeshima; Hisako Honjyo; Misako Yokoyama; Alexander Shestopalov; Yoshihiro Sakoda
  Viruses, 14, 10, 2022年09月30日, ［国際誌］
  英語, 研究論文（学術雑誌）, Many high pathogenicity avian influenza (HPAI) cases in wild birds due to H5N1 HPAI virus (HPAIV) infection were reported in northern Japan in the winter of 2021-2022. To investigate the epidemiology of HPAIVs brought to Japan from surrounding areas, a genetic analysis of H5 HPAIVs isolated in northern Japan was performed, and the pathogenicity of the HPAIV in chickens was assessed by experimental infection. Based on the genetic analysis of the hemagglutinin gene, pathogenic viruses detected in northern Japan as well as one in Sakhalin, the eastern part of Russia, were classified into the same subgroup as viruses prevalent in Europe in the same season but distinct from those circulating in Asia in winter 2020-2021. High identities of all eight segment sequences of A/crow/Hokkaido/0103B065/2022 (H5N1) (Crow/Hok), the representative isolates in northern Japan in 2022, to European isolates in the same season could also certify the unlikeliness of causing gene reassortment between H5 HPAIVs and viruses locally circulating in Asia. According to intranasal challenge results in six-week-old chickens, 50% of the chicken-lethal dose of Crow/Hok was calculated as 104.5 times of the 50% egg-infectious dose. These results demonstrated that the currently prevalent H5 HPAIVs could spread widely from certain origins throughout the Eurasian continent, including Europe and the Far East, and implied a possibility that contagious viruses are gathered in lakes in the northern territory via bird migration. Active monitoring of wild birds at the global level is essential to estimate the geographical source and spread dynamics of HPAIVs.
• 2022年に北海道内の野鳥から分離された高病原性鳥インフルエンザウイルスの遺伝子解析と感染猛禽類に対する治療の試み
  磯田 典和; 日尾野 隆大; 渡邊 有希子; 曽田 公輔; 遠藤 真由美; 小笠原 浩平; 山口 剛士; 大沼 学; 齋藤 慶輔; 迫田 義博
  日本獣医学会学術集会講演要旨集, 165回, [DV1A, 07], (公社)日本獣医学会, 2022年09月
  日本語
• バロキサビルマルボキシルのニワトリへの4週間反復経口投与による安全性評価
  三木 万梨子; 尾原 涼; 西村 享平; 岡 良子; 宍戸 貴雄; 福島 民雄; 吉本 淳; 中山 翔太; 木村 享史; 池中 良徳; 日尾野 隆大; 磯田 典和; 迫田 義博
  日本獣医学会学術集会講演要旨集, 165回, [DV1A, 08], (公社)日本獣医学会, 2022年09月
  日本語
• キタキツネ及びタヌキからの高病原性鳥インフルエンザウイルスの分離
  日尾野 隆大; 磯田 典和; 小林 篤史; 小林 大樹; 鈴木 玲海; 佐竹 優樹; 松野 啓太; 佐鹿 万里子; 伴 日向子; 小林 茉弥; 高谷 文仁; 冨士田 裕子; 木村 享史; 迫田 義博
  日本獣医学会学術集会講演要旨集, 165回, [DV1A, 09], (公社)日本獣医学会, 2022年09月
  日本語
• 高病原性鳥インフルエンザウイルスに感染したキタキツネの病理学的解析とウイルス受容体の検出
  小林 大樹; 小林 篤史; 日尾野 隆大; 原田 里桜; 鈴木 玲海; 松野 啓太; 磯田 典和; 高谷 文仁; 冨士田 裕子; 木村 享史; 迫田 義博
  日本獣医学会学術集会講演要旨集, 165回, [DV1A, 10], (公社)日本獣医学会, 2022年09月
  日本語
• 豚コレラマーカーワクチン由来キメラウイルスのレスキュー(Rescue of a chimeric virus derived from classical swine fever vaccine strain for marker vaccine)
  Huynh Tan Loc; 荻野 紗帆; 三村 優芽; 金 琢洙; 日尾野 隆大; 磯田 典和; 迫田 義博
  日本獣医学会学術集会講演要旨集, 165回, [DV3A, 10], (公社)日本獣医学会, 2022年09月
  英語
• 2021～2022年シーズンの野鳥における高病原性鳥インフルエンザウイルスの流行の特徴と考察
  小笠原 浩平; 渡辺 有希子; 磯田 典和; 日尾野 隆大; 安達 光; 河野 晴子; 大沼 学; 迫田 義博; 齊藤 慶輔
  北海道獣医師会雑誌, 66, 8, 302, 302, (公社)北海道獣医師会, 2022年08月
  日本語
• Turkeys possess diverse Siaα2-3Gal glycans that facilitate their dual susceptibility to avian influenza viruses isolated from ducks and chickens
  Daiki Kobayashi; Takahiro Hiono; Osamu Ichii; Shoko Nishihara; Sayaka Takase-Yoden; Kazuo Yamamoto; Hiroto Kawashima; Norikazu Isoda; Yoshihiro Sakoda
  Virus Research, 315, 2022年07月02日, ［査読有り］
  英語, 研究論文（学術雑誌）
• ANTIBIOGRAMS AND VIRULENCE GENES OF ESCHERICHIA COLI AND SALMONELLA SP FROM FARM PIGS IN CENTRAL THAILAND
  Pornthip Chompook; Apiradee Intarapak; Kanjana Changkaew; Ruttana Pachanon; Apichart Suwannachairob; Chie Nakajima; Yasuhiko Suzuki; Orasa Suthienkul; Norikazu Isoda
  Southeast Asian Journal of Tropical Medicine and Public Health, 53, 3, 322, 344, 2022年05月19日
  研究論文（学術雑誌）
• Risk profile of low pathogenicity avian influenza virus infections in farms in southern Vietnam.
  Kien Trung LE; Norikazu Isoda; Lam Thanh Nguyen; Duc-Huy Chu; Long Van Nguyen; Minh Quang Phan; Diep Thi Nguyen; Tien Ngoc Nguyen; Tien Ngoc Tien; Tung Thanh LE; Takahiro Hiono; Keita Matsuno; Masatoshi Okamatsu; Yoshihiro Sakoda
  The Journal of veterinary medical science, 84, 6, 860, 868, 2022年05月13日, ［国内誌］
  英語, 研究論文（学術雑誌）, The impact of low pathogenicity avian influenza (LPAI) has been confirmed mainly in farms. Unlike apparent losses caused by the high pathogenicity avian influenza (HPAI), the LPAI impact has been hardly evaluated due to underestimating its spread and damage. In 2019, a questionnaire study was conducted in southern Vietnam to identify the specific risk factors of LPAI virus (LPAIV) circulation and to find associations between husbandry activities and LPAI prevalence. A multilevel regression analysis indicated that keeping Muscovy ducks during farming contributed to LPAIV positivity [Odds ratio=208.2 (95% confidence interval: 13.4-1.1×104)]. In cluster analysis, farmers willing to report avian influenza (AI) events and who agreed with the local AI control policy had a slightly lower risk for LPAIV infection although there was no significance in the correlation between farmer characteristics and LPAI occurrence. These findings indicated that keeping Muscovy ducks without appropriate countermeasures might increase the risk of LPAIV infection. Furthermore, specific control measures at the local level are effective for LPAIV circulation, and the improvement of knowledge about biosecurity and attitude contributes to reducing LPAI damage.
• Assessment of ameliorative effects of organic dietary interventions on neonicotinoid exposure rates in a Japanese population.
  Collins Nimako; Takahiro Ichise; Hiroshi Hasegawa; Osei Akoto; Nathaniel O Boadi; Kumiko Taira; Kazutoshi Fujioka; Norikazu Isoda; Shouta M M Nakayama; Mayumi Ishizuka; Yoshinori Ikenaka
  Environment international, 162, 107169, 107169, 2022年04月, ［国際誌］
  英語, 研究論文（学術雑誌）, Neonicotinoid insecticides (NNIs) are a popular class of insecticides used in various pest management regimens worldwide. Biomonitoring studies continuously report high exposure rates of NNIs in various human populations across the globe. Yet, there is no validated countermeasure for combating the recent exponential rise in NNI exposure rates observed in human populations. The current study assessed the impacts of organic dietary interventions on NNI exposure rates in a Japanese population. A total of 103 volunteers were recruited into the study. Subjects were either served with Organic diets for 5 and 30 days or conventional diets. A total of 919 repeated urine samples were collected from the participants and then subjected to LC-MS/MS analysis to determine urinary concentrations of 7 NNIs parent compounds and an NNI metabolite. Eight NNIs were detected; with a decreasing detection frequency (%Dfs) pattern; desmethyl-acetamiprid (dm-ACE) (64.96%) > dinotefuran (52.12%), imidacloprid (39.61%) > clothianidin (33.95%) > thiamethoxam (28.51%) > acetamiprid (12.62%) > nitenpyram (5.33%) > thiacloprid (2.83%). Dinotefuran, dm-ACE, and clothianidin recorded the highest concentrations in the subjects. The %Df of NNIs in the 5-days or 30-days organic diet group were lower than those of the conventional diet consumers. The organic diet group showed lower rates of multiple NNI exposures than those of the conventional diet consumers. The mean and median cumulative levels of NNIs (median IMIeq) were significantly lower in the organic diet group than the conventional diet group (p < 0.0001). The estimated daily intakes (EDIs) of NNIs were higher in adults than children, but less than 1% of NNI cRfDs, except for clothianidin, which exhibited a %cRfD of 1.32 in children. Compared to the conventional diet group, the 5- and 30-day organic dietary intervention showed drastic reductions in NNI EDIs. Findings from the present study give credence to organic dietary interventions as potential ameliorative strategies for NNI exposure rates in human populations.
• Strategies for fighting pandemic virus infections: Integration of virology and drug delivery.
  Takashi Nakamura; Norikazu Isoda; Yoshihiro Sakoda; Hideyoshi Harashima
  Journal of controlled release : official journal of the Controlled Release Society, 343, 361, 378, 2022年03月, ［国際誌］
  英語, 研究論文（学術雑誌）, Respiratory viruses have sometimes resulted in worldwide pandemics, with the influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) being major participants. Long-term efforts have made it possible to control the influenza virus, but seasonal influenza continues to take many lives each year, and a pandemic influenza virus sometimes emerges. Although vaccines for coronavirus disease 2019 (COVID-19) have been developed, we are not yet able to coexist with the SARS-CoV-2. To overcome such viruses, it is necessary to obtain knowledge about international surveillance systems, virology, ecology and to determine that immune responses are effective. The information must then be transferred to drugs. Delivery systems would be expected to contribute to the rational development of drugs. In this review, virologist and drug delivery system (DDS) researchers discuss drug delivery strategies, especially the use of lipid-based nanocarriers, for fighting to respiratory virus infections.
• Endemic infections of bovine viral diarrhea virus genotypes 1b and 2a isolated from cattle in Japan between 2014 and 2020.
  Asami Nishimori; Shizuka Hirose; Saho Ogino; Kiyohiko Andoh; Norikazu Isoda; Yoshihiro Sakoda
  The Journal of veterinary medical science, 84, 2, 228, 232, 2022年02月10日, ［国内誌］
  英語, 研究論文（学術雑誌）, Bovine viral diarrhea virus (BVDV) is a causative agent of bovine viral diarrhea. In Japan, a previous study reported that subgenotype 1b viruses were predominant until 2014. Because there is little information regarding the recent epidemiological status of BVDV circulating in Japan, we performed genetic characterization of 909 BVDV isolates obtained between 2014 and 2020. We found that 657 and 252 isolates were classified as BVDV-1 and BVDV-2, respectively, and that they were further subdivided into 1a (35 isolates, 3.9%), 1b (588, 64.7%), 1c (34, 3.7%), and 2a (252, 27.7%). Phylogenetic analysis using entire E2 coding sequence revealed that a major domestic cluster in Japan among BVDV-1b and 2a viruses were unchanged from a previous study conducted from 2006 to 2014. These results provide updated information concerning the epidemic strain of BVDV in Japan, which would be helpful for appropriate vaccine selection.
• Antiviral Effects of 5-Aminolevulinic Acid Phosphate against Classical Swine Fever Virus: In Vitro and In Vivo Evaluation.
  Shizuka Hirose; Norikazu Isoda; Loc Tan Huynh; Taksoo Kim; Keiichiro Yoshimoto; Tohru Tanaka; Kenjiro Inui; Takahiro Hiono; Yoshihiro Sakoda
  Pathogens (Basel, Switzerland), 11, 2, 2022年01月27日, ［国際誌］
  英語, 研究論文（学術雑誌）, The inhibitory effects of 5-aminolevulinic acid phosphate (5-ALA), an important amino acid for energy production in the host, against viral infections were previously reported. Here, the antiviral effects of 5-ALA against classical swine fever virus (CSFV) belonging to the genus Pestivirus in the Flaviviridae family and its possible mechanisms were investigated. CSFV replication was suppressed in swine cells supplemented with 5-ALA or its metabolite, protoporphyrin IX (PPIX). The infectivity titer of CSFV was decreased after mixing with PPIX extracellularly. In addition, the activities of the replication cycle were decreased in the presence of PPIX based on the CSFV replicon assay. These results showed that PPIX exerted antiviral effects by inactivating virus particles and inhibiting the replication cycle. To evaluate the in vivo efficacy of 5-ALA, pigs were supplemented daily with 5-ALA for 1 week before virus inoculation and then inoculated with a virulent CSFV strain at the 107.0 50% tissue culture infectious dose. The clinical scores of the supplemented group were significantly lower than those of the nonsupplemented group, whereas the virus growth was not. Taken together, 5-ALA showed antiviral effects against CSFV in vitro, and PPIX played a key role by inactivating virus particles extracellularly and inhibiting the replication cycle intracellularly.
• A systematic approach to illuminate a new hot spot of avian influenza virus circulation in South Vietnam, 2016-2017.
  Kien Trung Le; Mark A Stevenson; Norikazu Isoda; Lam Thanh Nguyen; Duc-Huy Chu; Tien Ngoc Nguyen; Long Van Nguyen; Tien Ngoc Tien; Tung Thanh Le; Keita Matsuno; Masatoshi Okamatsu; Yoshihiro Sakoda
  Transboundary and emerging diseases, 2021年11月04日, ［国際誌］
  英語, 研究論文（学術雑誌）, In South Vietnam, live bird markets (LBMs) are key in the value chain of poultry products and spread of avian influenza virus (AIV) although they may not be the sole determinant of AIV prevalence. For this reason, a risk analysis of AIV prevalence was conducted accounting for all value chain factors. A cross-sectional study of poultry flock managers and poultry on backyard farms, commercial (high biosecurity) farms, LBMs and poultry delivery stations (PDSs) in four districts of Vinh Long province was conducted between December 2016 and August 2017. A total of 3597 swab samples were collected from birds from 101 backyard farms, 50 commercial farms, 58 sellers in LBMs and 19 traders in PDSs. Swab samples were submitted for AIV isolation. At the same time a questionnaire was administered to flock managers asking them to provide details of their knowledge, attitude and practices related to avian influenza. Multiple correspondence analysis and a mixed-effects multivariable logistic regression model were developed to identify enterprise and flock manager characteristics that increased the risk of AIV positivity. A total of 274 birds were positive for AIV isolation, returning an estimated true prevalence of 7.6% [95% confidence interval (CI): 6.8%-8.5%]. The odds of a bird being AIV positive if it was from an LBM or PDS were 45 (95% CI: 3.4-590) and 25 (95% CI: 1.4-460), respectively, times higher to the odds of a bird from a commercial poultry farm being AIV positive. The odds of birds being AIV positive for respondents with a mixed (uncertain or inconsistent) level and a low level of knowledge about AI were 5.0 (95% CI: 0.20-130) and 3.5 (95% CI: 0.2-62), respectively, times higher to the odd of birds being positive for respondents with a good knowledge of AI. LBMs and PDSs should receive specific emphasis in AI control programs in Vietnam. Our findings provide evidence to support the hypothesis that incomplete respondent knowledge of AI and AIV spread mechanism were associated with an increased risk of AIV positivity. Delivery of education programs specifically designed for those in each enterprise will assist in this regard. The timing and frequency of delivery of education programs are likely to be important if the turnover of those working in LBMs and PDSs is high.
• Establishment of a mouse- and egg-adapted strain for the evaluation of vaccine potency against H3N2 variant influenza virus in mice.
  Enkhbold Bazarragchaa; Takahiro Hiono; Norikazu Isoda; Hirotaka Hayashi; Masatoshi Okamatsu; Yoshihiro Sakoda
  The Journal of veterinary medical science, 83, 11, 1694, 1701, 2021年10月31日, ［国内誌］
  英語, 研究論文（学術雑誌）, Sporadic spreads of swine-origin influenza H3N2 variant (H3N2v) viruses were reported in humans, resulting in 437 human infections between 2011 and 2021 in the USA. Thus, an effective vaccine is needed to better control a potential pandemic for these antigenically distinct viruses from seasonal influenza. In this study, a candidate vaccine strain with efficient growth capacity in chicken embryos was established through serial blind passaging of A/Indiana/08/2011 (H3N2)v in mice and chicken embryos. Seven amino acid substitutions (M21I in PA; A138T, N165K, and V226A in HA; S312L in NP; T167I in M1; G62A in NS1 proteins) were found in the passaged viruses without a major change in the antigenicity. This mouse- and egg-adapted virus was used as a vaccine and challenge strain in mice to evaluate the efficacy of the H3N2v vaccine in different doses. Antibodies with high neutralizing titers were induced in mice immunized with 100 µg of inactivated whole-virus particles, and those mice were significantly protected from the challenge of homologous strain. The findings indicated that the established strain in the study was useful for vaccine study in mouse models.
• Characteristics of Classical Swine Fever Virus Variants Derived from Live Attenuated GPE- Vaccine Seed.
  Taksoo Kim; Loc Tan Huynh; Shizuka Hirose; Manabu Igarashi; Takahiro Hiono; Norikazu Isoda; Yoshihiro Sakoda
  Viruses, 13, 8, 2021年08月23日, ［国際誌］
  英語, 研究論文（学術雑誌）, The GPE- strain is a live attenuated vaccine for classical swine fever (CSF) developed in Japan. In the context of increasing attention for the differentiating infected from vaccinated animals (DIVA) concept, the achievement of CSF eradication with the GPE- proposes it as a preferable backbone for a recombinant CSF marker vaccine. While its infectious cDNA clone, vGPE-, is well characterized, 10 amino acid substitutions were recognized in the genome, compared to the original GPE- vaccine seed. To clarify the GPE- seed availability, this study aimed to generate and characterize a clone possessing the identical amino acid sequence to the GPE- seed. The attempt resulted in the loss of the infectious GPE- seed clone production due to the impaired replication by an amino acid substitution in the viral polymerase NS5B. Accordingly, replication-competent GPE- seed variant clones were produced. Although they were mostly restricted to propagate in the tonsils of pigs, similarly to vGPE-, their type I interferon-inducing capacity was significantly lower than that of vGPE-. Taken together, vGPE- mainly retains ideal properties for the CSF vaccine, compared with the seed variants, and is probably useful in the development of a CSF marker vaccine.
• Prevalence and Multidrug-Resistance Salmonella in Swine Production Chain in a Central Province, Thailand.
  Kaknokrat Chonsin; Ruchirada Changkwanyeun; Achiraya Siriphap; Apiradee Intarapuk; Watsawan Prapasawat; Kanjana Changkaew; Chaiwat Pulsrikan; Norikazu Isoda; Chie Nakajima; Yasuhiko Suzuki; Orasa Suthienkul
  Journal of food protection, 84, 12, 2174, 2184, 2021年08月19日, ［国際誌］
  英語, 研究論文（学術雑誌）, Salmonella causes foodborne disease outbreaks worldwide and raises considerable concerns about public health and economic losses. To determine prevalence, serovar, antimicrobial resistance (AMR) patterns, and extended-spectrum beta-lactamase (ESBL) genes, the present cross-sectional study collected a total of 418 fecal, carcass (three slaughterhouses), pork and cutting board (four markets) samples from a province in central Thailand in 2017 and 2018. Results showed that 65.1% (272/418) of samples were positive for Salmonella. The percentage of Salmonella positive samples from markets (88.8%; 158/178) was significantly higher than those from slaughterhouses (47.5%; 114/240) ( P<0.05 ). In total, 1,030 isolates were identified; of these, 409 were assigned to 45 serovars with S. Rissen (20%; 82/409) being the most common. New serovars of Thai isolates, S. Cannstatt and S. Braubach, were identified in market and slaughterhouse samples, respectively. AMR of Salmonella isolates showed that 73.9% (133/180) of 19 different serovars exhibited multidrug resistance (MDR). Screening for ESBL production showed that 10.3% (41/399) of isolates were ESBL positive. ESBL-producing Salmonella isolates in market samples (75.6%; 31/41) were significantly higher than those in slaughterhouse samples (24.4%; 10/41) ( P<0.05 ). In market samples, 77.4% (24/31) were isolated from pork and 22.6% (7/31) from cutting boards. Nine ESBL-producing isolates carried single type ESBL genes bla TEM (9.8%; 4/41) or bla CTX-M (12.2%; 5/41), while 11 (26.8%) carried both bla TEM and bla CTX-M . No ESBL-producing Salmonella isolate carried the gene bla SHV . Results suggest that pigs, their flesh, and cutting boards could be reservoirs for widespread MDR, ESBL-producing Salmonella outbreak across the food chain.
• Transmission Dynamics of Bovine Viral Diarrhea Virus in Hokkaido, Japan by Phylogenetic and Epidemiological Network Approaches.
  Shizuka Hirose; Kosuke Notsu; Satoshi Ito; Yoshihiro Sakoda; Norikazu Isoda
  Pathogens (Basel, Switzerland), 10, 8, 2021年07月21日, ［国際誌］
  英語, 研究論文（学術雑誌）, Bovine viral diarrhea (BVD) caused by BVD virus (BVDV) leads to economic loss worldwide. Cattle that are persistently infected (PI) with BVDV are known to play an important role in viral transmission in association with the animal movement, as they shed the virus during their lifetime. In this research, the "hot spot" for BVD transmission was estimated by combining phylogenetic and epidemiological analyses for PI cattle and cattle that lived together on BVDV affected farms in Tokachi district, Hokkaido prefecture, Japan. Viral isolates were genetically categorized into BVDV-1a, 1b, and 2a, based on the nucleotide sequence of the entire E2 region. In BVDV genotype 1, subgenotype b (BVDV-1b), cluster I was identified as the majority in Tokachi district. Network analysis indicated that 12 of the 15 affected farms had cattle movements from other facilities (PI-network) and farms affected with BVDV-1b cluster I consisted of a large network. It was implied that the number of cattle movements themselves would be a risk of BVD transmission, using the PageRank algorithm. Therefore, these results demonstrate that cattle movements would contribute to disease spread and the combination of virological and epidemiological analysis methods would be beneficial in determining possible virus transmission routes.
• Immunization Coverage and Antibody Retention against Rabies in Domestic Dogs in Lusaka District, Zambia.
  Chiho Kaneko; Michihito Sasaki; Ryosuke Omori; Ryo Nakao; Chikako Kataoka-Nakamura; Ladslav Moonga; Joseph Ndebe; Walter Muleya; Edgar Simulundu; Bernard M Hang'ombe; George Dautu; Masahiro Kajihara; Akina Mori-Kajihara; Yongjin Qiu; Naoto Ito; Herman M Chambaro; Chihiro Sugimoto; Hideaki Higashi; Ayato Takada; Hirofumi Sawa; Aaron S Mweene; Norikazu Isoda
  Pathogens (Basel, Switzerland), 10, 6, 2021年06月11日, ［国際誌］
  英語, 研究論文（学術雑誌）, Rabies remains endemic in Zambia. Despite conducting canine vaccinations in Lusaka district, the vaccination coverage and actual seropositivity in the dog population in Lusaka district are rarely evaluated. This study estimated the seropositivity-based immunization coverage in the owned dog population in Lusaka district using the expanded program on immunization cluster survey method. The time-series trend of neutralizing antibodies against rabies in vaccinated dogs was also evaluated. Of 366 dogs in 200 dog-owning households in Lusaka district, blood samples were collected successfully from 251 dogs. In the sampled dogs, 42.2% (106/251) had an antibody titer ≥0.5 IU/mL. When the 115 dogs whose blood was not collected were assumed to be seronegative, the minimum immunization coverage in Lusaka district's owned dog population was estimated at 29.0% (95% confidence interval: 22.4-35.5). It was also found that a single vaccination with certified vaccines is capable of inducing protective levels of antibodies. In contrast, higher antibody titers were observed in multiple-vaccinated dogs than in single-vaccinated dogs, coupled with the observation of a decline in antibody titer over time. These results suggest the importance of continuous booster immunization to maintain herd immunity and provide useful information to plan mass vaccination against rabies in Zambia.
• Domestic dog demographics and estimates of canine vaccination coverage in a rural area of Zambia for the elimination of rabies.
  Chiho Kaneko; Ryosuke Omori; Michihito Sasaki; Chikako Kataoka-Nakamura; Edgar Simulundu; Walter Muleya; Ladslav Moonga; Joseph Ndebe; Bernard M Hang'ombe; George Dautu; Yongjin Qiu; Ryo Nakao; Masahiro Kajihara; Akina Mori-Kajihara; Herman M Chambaro; Hideaki Higashi; Chihiro Sugimoto; Hirofumi Sawa; Aaron S Mweene; Ayato Takada; Norikazu Isoda
  PLoS neglected tropical diseases, 15, 4, e0009222, 2021年04月, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: An estimated 75% or more of the human rabies cases in Africa occur in rural settings, which underscores the importance of rabies control in these areas. Understanding dog demographics can help design strategies for rabies control and plan and conduct canine mass vaccination campaigns effectively in African countries. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional survey was conducted to investigate domestic dog demographics in Kalambabakali, in the rural Mazabuka District of Zambia. The population of ownerless dogs and the total achievable vaccination coverage among the total dog population was estimated using the capture-recapture-based Bayesian model by conducting a canine mass vaccination campaign. This study revealed that 29% of the domestic dog population was under one year old, and 57.7% of those were under three months old and thus were not eligible for the canine rabies vaccination in Zambia. The population growth was estimated at 15% per annum based on the cross-sectional household survey. The population of ownerless dogs was estimated to be small, with an ownerless-to-owned-dog ratio of 0.01-0.06 in the target zones. The achieved overall vaccination coverage from the first mass vaccination was estimated 19.8-51.6%. This low coverage was principally attributed to the owners' lack of information, unavailability, and dog-handling difficulties. The follow-up mass vaccination campaign achieved an overall coverage of 54.8-76.2%. CONCLUSIONS/SIGNIFICANCE: This paper indicates the potential for controlling canine rabies through mass vaccination in rural Zambia. Rabies education and responsible dog ownership are required to achieve high and sustainable vaccination coverage. Our findings also propose including puppies below three months old in the target population for rabies vaccination and emphasize that securing an annual enforcement of canine mass vaccination that reaches 70% coverage in the dog population is necessary to maintain protective herd immunity.
• Efficacy of Oral Vaccine against Classical Swine Fever in Wild Boar and Estimation of the Disease Dynamics in the Quantitative Approach.
  Enkhbold Bazarragchaa; Norikazu Isoda; Taksoo Kim; Madoka Tetsuo; Satoshi Ito; Keita Matsuno; Yoshihiro Sakoda
  Viruses, 13, 2, 2021年02月20日, ［国際誌］
  英語, 研究論文（学術雑誌）, Classical swine fever virus (CSFV) in the wild boar population has been spreading in Japan, alongside outbreaks on pigs, since classical swine fever (CSF) reemerged in September 2018. The vaccination using oral bait vaccine was initially implemented in Gifu prefecture in March 2019. In the present study, antibodies against CSFV in wild boar were assessed in 1443 captured and dead wild boars in Gifu prefecture. After the implementation of oral vaccination, the increase of the proportion of seropositive animals and their titer in wild boars were confirmed. Quantitative analysis of antigen and antibodies against CSFV in wild boar implies potential disease diversity in the wild boar population. Animals with status in high virus replication (Ct < 30) and non- or low-immune response were confirmed and were sustained at a certain level after initial oral vaccination. Through continuous vaccination periods, the increase of seroprevalence among wild boar and the decrease of CSFV-positive animals were observed. The epidemiological analysis based on the quantitative virological outcomes could provide more information on the efficacy of oral vaccination and dynamics of CSF in the wild boar population, which will help to improve the implementation of control measures for CSF in countries such as Japan and neighboring countries.
• A New Variant Among Newcastle Disease Viruses Isolated in the Democratic Republic of the Congo in 2018 and 2019.
  Augustin T Twabela; Lam Thanh Nguyen; Justin Masumu; Patrick Mpoyo; Serge Mpiana; Julienne Sumbu; Masatoshi Okamatsu; Keita Matsuno; Norikazu Isoda; Bianca Zecchin; Isabella Monne; Yoshihiro Sakoda
  Viruses, 13, 2, 2021年01月20日, ［国際誌］
  英語, 研究論文（学術雑誌）, Newcastle disease (ND) is a highly transmissible and devastating disease that affects poultry and wild birds worldwide. Comprehensive knowledge regarding the characteristics and epidemiological factors of the ND virus (NDV) is critical for the control and prevention of ND. Effective vaccinations can prevent and control the spread of the NDV in poultry populations. For decades, the Democratic Republic of the Congo (DRC) has reported the impacts of ND on commercial and traditional poultry farming systems. The reports were preliminary clinical observations, and few cases were confirmed in the laboratory. However, data on the phylogenetic, genetic, and virological characteristics of NDVs circulating in the DRC are not available. In this study, the whole-genome sequences of three NDV isolates obtained using the next-generation sequencing method revealed two isolates that were a new variant of NDV, and one isolate that was clustered in the subgenotype VII.2. All DRC isolates were velogenic and were antigenically closely related to the vaccine strains. Our findings reveal that despite the circulation of the new variant, ND can be controlled in the DRC using the current vaccine. However, epidemiological studies should be conducted to elucidate the endemicity of the disease so that better control strategies can be implemented.
• Potency of an Inactivated Influenza Vaccine against a Challenge with A/Swine/Missouri/A01727926/2015 (H4N6) in Mice for Pandemic Preparedness.
  Hirotaka Hayashi; Norikazu Isoda; Enkhbold Bazarragchaa; Naoki Nomura; Keita Matsuno; Masatoshi Okamatsu; Hiroshi Kida; Yoshihiro Sakoda
  Vaccines, 8, 4, 2020年12月16日, ［国際誌］
  英語, 研究論文（学術雑誌）, H4 influenza viruses have been isolated from birds across the world. In recent years, an H4 influenza virus infection has been confirmed in pigs. Pigs play an important role in the transmission of influenza viruses to human hosts. Therefore, it is important to develop a new vaccine in the case of an H4 influenza virus infection in humans, considering that this virus has a different antigenicity from seasonal human influenza viruses. In this study, after selecting vaccine candidate strains based on their antigenic relation to one of the pig isolates, A/swine/Missouri/A01727926/2015 (H4N6) (MO/15), an inactivated whole-particle vaccine was prepared from A/swan/Hokkaido/481102/2017 (H4N6). This vaccine showed high immunogenicity in mice, and the antibody induced by the vaccine showed high cross-reactivity to the MO/15 virus. This vaccine induced sufficient neutralizing antibodies and mitigated the effects of an MO/15 infection in a mouse model. This study is the first to suggest that an inactivated whole-particle vaccine prepared from an influenza virus isolated from wild birds is an effective countermeasure in case of a future influenza pandemic caused by the H4 influenza virus.
• Re-Invasion of H5N8 High Pathogenicity Avian Influenza Virus Clade 2.3.4.4b in Hokkaido, Japan, 2020.
  Norikazu Isoda; Augustin T Twabela; Enkhbold Bazarragchaa; Kohei Ogasawara; Hirotaka Hayashi; Zu-Jyun Wang; Daiki Kobayashi; Yukiko Watanabe; Keisuke Saito; Hiroshi Kida; Yoshihiro Sakoda
  Viruses, 12, 12, 2020年12月14日, ［国際誌］
  英語, 研究論文（学術雑誌）, Global dispersion of high pathogenicity avian influenza (HPAI), especially that caused by H5 clade 2.3.4.4, has threatened poultry industries and, potentially, human health. An HPAI virus, A/northern pintail/Hokkaido/M13/2020 (H5N8) (NP/Hok/20) belonging to clade 2.3.4.4b, was isolated from a fecal sample collected at a lake in Hokkaido, Japan where migratory birds rested, October 2020. In the phylogenetic trees of all eight gene segments, NP/Hok/20 fell into in the cluster of European isolates in 2020, but was distinct from the isolates in eastern Asia and Europe during the winter season of 2017-2018. The antigenic cartography indicates that the antigenicity of NP/Hok/20 was almost the same as that of previous isolates of H5 clade 2.3.4.4b, whereas the antigenic distances from NP/Hok/20 to the representative strains in clade 2.3.4.4e and to a strain in 2.3.4 were apparently distant. These data imply that HPAI virus clade 2.3.4.4b should have been delivered by bird migration despite the intercontinental distance, although it was not defined whether NP/Hok/20 was transported from Europe via Siberia where migratory birds nest in the summer season. Given the probability of perpetuation of transmission in the northern territory, periodic updates of intensive surveys on avian influenza at the global level are essential to prepare for future outbreaks of the HPAI virus.
• Evaluation of Baloxavir Marboxil and Peramivir for the Treatment of High Pathogenicity Avian Influenza in Chickens.
  Augustin Twabela; Masatoshi Okamatsu; Keita Matsuno; Norikazu Isoda; Yoshihiro Sakoda
  Viruses, 12, 12, 2020年12月08日, ［国際誌］
  英語, 研究論文（学術雑誌）, Control measures in the case of high pathogenicity avian influenza (HPAI) outbreaks in poultry include culling, surveillance, and biosecurity; wild birds in captivity may also be culled, although some rare bird species should be rescued for conservation. In this study, two anti-influenza drugs, baloxavir marboxil (BXM) and peramivir (PR), used in humans, were examined in treating HPAI in birds, using chickens as a model. Chickens were infected with H5N6 HPAI virus and were treated immediately or 24 h from challenge with 20 mg/kg BXM or PR twice a day for five days. As per our findings, BXM significantly reduced virus replication in organs and provided full protection to chickens compared with that induced by PR. In the 24-h-delayed treatment, neither drug completely inhibited virus replication nor ensured the survival of infected chickens. A single administration of 2.5 mg/kg of BXM was determined as the minimum dose required to fully protect chickens from HPAI virus; the concentration of baloxavir acid, the active form of BXM, in chicken blood at this dose was sufficient for a 48 h antiviral effect post-administration. Thus, these data can be a starting point for the use of BXM and PR in treating captive wild birds infected with HPAI virus.
• 時空間解析を用いた日本における野生イノシシ群での豚熱感染拡大評価
  磯田 典和; 馬場 開陸; 伊藤 聡; 伊藤 貢; 迫田 義博; 蒔田 浩平
  獣医疫学雑誌, 24, 2, 81, 82, 獣医疫学会, 2020年12月
  日本語
• 野生イノシシにおけるCSF感染拡大様式評価のための地域2ヵ月期間有病率推定
  馬場 開陸; 磯田 典和; 伊藤 聡; 伊藤 貢; 迫田 義博; 蒔田 浩平
  獣医疫学雑誌, 24, 2, 83, 84, 獣医疫学会, 2020年12月
  日本語
• Molecular analysis of streptomycin-resistance associating genes in Mycobacterium tuberculosis isolates from Nepal.
  Dipti Shrestha; Bhagwan Maharjan; Nan Aye Thida Oo; Norikazu Isoda; Chie Nakajima; Yasuhiko Suzuki
  Tuberculosis (Edinburgh, Scotland), 125, 101985, 101985, 2020年12月, ［国際誌］
  英語, 研究論文（学術雑誌）, Mutation in rpsL (encoding ribosomal protein S12), rrs (encoding 16S ribosomal RNA) and gidB (encoding 7-methylguanosine methyltransferase) are associated with resistance to streptomycin (STR), which is used for the treatment of multi-drug resistant tuberculosis (MDR-TB) in Nepal. The aim of our study is to analyze the correlation between mutations in the target genes and STR-resistance in 197 Mycobacterium tuberculosis (MTB) isolates from Nepal. Mutations in rpsL was harbored by 65.9% of isolates, in which the most common mutation in rpsL is caused by K43R (58.8%) and were significantly associated with Beijing genotype (P < 0.001). About 13.2% of isolates harbored mutations in two highly mutable regions of rrs, the 530 loop and the 912 region. About 13.2% of gidB mutants do not show any mutation in rpsL and rrs, which might suggest the role of gidB mutations in STR-resistance in MTB. In addition, 5.6% of isolates do not show any mutations in three genes examined, suggesting the involvement of other mechanism in STR-resistance in MTB. Our findings can be implemented for the establishment of molecular STR-susceptibility testing, in which tuberculosis can be treated with appropriate drugs and can improve control strategies for DR-TB.
• 2016-2017年のベトナム南部での疫学的研究から明らかになった、鳥インフルエンザウイルスの新たなホットスポットの意義(The implication of a new hot spot of avian influenza based on epidemiological study in southern Vietnam in 2016-2017)
  Le Trung Kien; 磯田 典和; Nguyen Thanh Lam; Chu Duc-Huy; Tien Tien Ngoc; 松野 啓太; 岡松 正敏; 喜田 宏; 迫田 義博; 北海道大人獣共通感染症リサーチセンター/国際協働ユニット
  日本獣医学会学術集会講演要旨集, 163回, 232, 232, (公社)日本獣医学会, 2020年10月
  英語
• ウイルス学的解析および疫学的解析を用いた北海道十勝地方における牛ウイルス性下痢ウイルスの伝播経路解明
  廣瀬 静香; 野津 昂亮; 松野 啓太; 岡松 正敏; 川本 恵子; 磯田 典和; 迫田 義博
  日本獣医学会学術集会講演要旨集, 163回, 236, 236, (公社)日本獣医学会, 2020年10月
  日本語
• 日本の岐阜県にてイノシシから採取した血中古典的ブタ熱ウイルス抗原と抗体に関する定量分析(Quantitative analysis of antigen and antibody of classical swine fever virus in wild boar sera collected in Gifu prefecture, Japan)
  Enkhbold Bazarragchaa; 金 琢洙; 哲翁 まどか; 磯田 典和; 松野 啓太; 迫田 義博; 北海道大人獣共通感染症リサーチセンター/国際協働ユニット
  日本獣医学会学術集会講演要旨集, 163回, 243, 243, (公社)日本獣医学会, 2020年10月
  英語
• Oral Supplementation of the Vitamin D Metabolite 25(OH)D3 Against Influenza Virus Infection in Mice.
  Hirotaka Hayashi; Masatoshi Okamatsu; Honami Ogasawara; Naoko Tsugawa; Norikazu Isoda; Keita Matsuno; Yoshihiro Sakoda
  Nutrients, 12, 7, 2020年07月05日, ［国際誌］
  英語, 研究論文（学術雑誌）, 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.
• Risk Assessment of African Swine Fever Virus Exposure to Sus scrofa in Japan Via Pork Products Brought in Air Passengers' Luggage.
  Satoshi Ito; Jaime Bosch; Cristina Jurado; José Manuel Sánchez-Vizcaíno; Norikazu Isoda
  Pathogens (Basel, Switzerland), 9, 4, 2020年04月20日, ［国際誌］
  英語, 研究論文（学術雑誌）, In recent years, African swine fever (ASF) has become prevalent in many areas, including Asia. The repeated detection of the ASF virus (ASFV) genome in pork products brought in air passenger's luggage (PPAP) was also reported from Japanese airports. In the present study, the risk of ASFV exposure to susceptible hosts in Japan via three different pathways was assessed. Two quantitative stochastic risk assessment models were built to estimate the annual probability of ASFV exposure to domestic pigs, which could be attributed to foreign job trainees or foreign tourists. A semi-quantitative stochastic model was built to assess the risk of ASFV exposure to wild boar caused by foreign tourists. The overall mean annual probability of ASFV exposure to domestic pigs via PPAP carried by foreign job trainees was 0.169 [95% confidence interval (CI): 0.000-0.600], whereas that by foreign tourists was 0.050 [95% CI: 0.000-0.214], corresponding to approximately one introduction every 5.9 and 20 years, respectively. The risk of ASFV exposure to domestic pigs was dispersed over the country, whereas that of wild boar was generally higher in the western part of Japan, indicating that the characteristics of the potential ASF risk in each prefecture were varied.
• Quantitative risk assessment of African swine fever virus introduction to Japan via pork products brought in air passengers' luggage.
  Satoshi Ito; Cristina Jurado; José Manuel Sánchez-Vizcaíno; Norikazu Isoda
  Transboundary and emerging diseases, 67, 2, 894, 905, 2020年03月, ［国際誌］
  英語, 研究論文（学術雑誌）, The spread of African swine fever (ASF) has reached pandemic levels over the last decade, and outbreaks of this disease in China, Mongolia, Vietnam and Cambodia in 2018 and 2019 could accelerate its transmission to neighbouring Asian territories. Thus, the risk that the ASF virus (ASFV) will be introduced to disease-free territories increases each year. Since Japan is an island nation, the most likely way in which ASFV would be introduced is via pork products brought in air passengers' luggage (PPAP). Therefore, in the present study, we assessed the risk of ASFV introduction to Japan via PPAP. For the purposes of this analysis, we considered 214 international commercial flights travelling from 47 origin territories to 31 destination airports as potential routes of ASFV introduction via PPAP. The risk was estimated quantitatively through a stochastic model that considered the volume of air passengers' luggage, the amount of confiscated pork products that were carried in air passengers' luggage and the disease status of the origin territory. The overall mean annual probability of ASFV introduction to Japan via PPAP was found to be 0.941 [95% confidence interval (CI), 0.661-1.000], which approximately corresponds to one introduction every 1.06 years. At the origin territory level, Mongolia was led as the highest risk territory, with a risk of 0.864 (95% CI, 0.434-1.000), followed by China (0.697; 0.223-0.999), Vietnam (0.662; 0.196-0.998) and the Russian Federation (0.136; 0.018-0.401). At the destination airport level, Narita International Airport had the highest risk (0.905; 0.537-1.000), followed by Kansai International Airport (0.496; 0.109-0.961), Tokyo International Airport (0.389; 0.072-0.879) and Chubu Centrair International Airport (0.338; 0.058-0.816). This information will help improve risk management activities and monitoring systems to prevent the introduction of ASFV to Japan.
• Dynamics of Classical Swine Fever Spread in Wild Boar in 2018-2019, Japan.
  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］, ［国際誌］
  英語, 研究論文（学術雑誌）, 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.
• Review on counter measures to coronavirus disease 2019 (COVID-19) pandemic, May 2020
  Taishi Kidaka; Sithumini M.W. Lokupathirage; Bungiriye Devinda Shameera Muthusinghe; Boniface Lombe Pongombo; Christida Estu Wastika; Zhouxing Wei; Shizuka Yoshioka; Mayumi Ishizuka; Yoshihiro Sakoda; Hiroaki Kariwa; Norikazu Isoda
  Japanese Journal of Veterinary Research, 68, 3, 133, 150, 2020年
  研究論文（学術雑誌）
• Role of Wild Boar in the Spread of Classical Swine Fever in Japan.
  Satoshi Ito; Cristina Jurado; Jaime Bosch; Mitsugi Ito; José Manuel Sánchez-Vizcaíno; Norikazu Isoda; And Yoshihiro Sakoda
  Pathogens (Basel, Switzerland), 8, 4, 2019年10月24日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, 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.
• Slaughterhouse survey for detection of bovine viral diarrhea infection among beef cattle in Kyushu, Japan.
  Agah MA; Notsu K; El-Khaiat HM; Arikawa G; Kubo M; Mitoma S; Okabayashi T; Mekata H; Elhanafy E; El Daous H; Mai TN; Nguyen TH; Isoda N; Sakoda Y; Norimine J; Sekiguchi S
  The Journal of veterinary medical science, 81, 10, 1450, 1454, 2019年10月18日, ［査読有り］, ［国内誌］
  英語, 研究論文（学術雑誌）, 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.
• Complete Genome Sequence of Rickettsia asiatica Strain Maytaro1284, a Member of Spotted Fever Group Rickettsiae Isolated from an Ixodes ovatus Tick in Japan.
  Thu MJ; Qiu Y; Yamagishi J; Kusakisako K; Ogata S; Moustafa MAM; Isoda N; Sugimoto C; Katakura K; Nonaka N; Nakao R
  Microbiology resource announcements, 8, 37, 2019年09月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, This is the first report of the complete genome sequence of Rickettsia asiatica strain Maytaro1284, isolated from an Ixodes ovatus tick in Japan. The genome contains a 1,344,324-bp circular chromosome and one plasmid of 74,761 bp. There was no outer membrane protein A (ompA) gene encoded in the genome.
• A Novel Combination of Prion Strain Co-Occurrence in Patients with Sporadic Creutzfeldt-Jakob Disease.
  Atsushi Kobayashi; Yasushi Iwasaki; Masaki Takao; Yuko Saito; Toru Iwaki; Zechen Qi; Ryouta Torimoto; Taishi Shimazaki; Yoshiko Munesue; Norikazu Isoda; Hirofumi Sawa; Keisuke Aoshima; Takashi Kimura; Hinako Kondo; Shirou Mohri; Tetsuyuki Kitamoto
  The American journal of pathology, 189, 6, 1276, 1283, 2019年06月, ［国際誌］
  英語, 研究論文（学術雑誌）, Six subgroups of sporadic Creutzfeldt-Jakob disease have been identified by distinctive clinicopathologic features, genotype at polymorphic codon 129 [methionine (M)/valine (V)] of the PRNP gene, and type of abnormal prion proteins (type 1 or 2). In addition to the pure subgroups, mixed neuropathologic features and the coexistence of two types of abnormal prion proteins in the same patient also have been reported. Here, we found that a portion of the patients previously diagnosed as MM1 had neuropathologic characteristics of the MM2 thalamic form (ie, neuronal loss of the inferior olivary nucleus of the medulla). Furthermore, coexistence of biochemical features of the MM2 thalamic form also was confirmed in the identified cases. In addition, in transmission experiments using prion protein-humanized mice, the brain material from the identified case showed weak infectivity and generated characteristic abnormal prion proteins in the inoculated mice resembling those after inoculation with brain material of MM2 thalamic form. Taken together, these results show that the co-occurrence of MM1 and MM2 thalamic form is a novel entity of sporadic Creutzfeldt-Jakob disease prion strain co-occurrence. The present study raises the possibility that the co-occurrence of the MM2 thalamic form might have been overlooked so far because of the scarcity of abnormal prion protein accumulation and restricted neuropathology.
• Spatiotemporal and risk analysis of H5 highly pathogenic avian influenza in Vietnam, 2014-2017.
  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, 2019年04月22日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, 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.
• Assessment of the cost effectiveness of compulsory testing of introduced animals and bulk tank milk testing for bovine viral diarrhea in Japan.
  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］, ［国内誌］
  英語, 研究論文（学術雑誌）, 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.
• Genetic diversity of Mycobacterium tuberculosis Central Asian Strain isolates from Nepal and comparison with neighboring countries.
  Yogendra Shah; Ajay Poudel; Bhagwan Maharjan; Jeewan Thapa; Tomoyuki Yamaguchi; Hassan Mahmoud Diab; Basu Dev Pandey; Eddie Solo; Norikazu Isoda; Yasuhiko Suzuki; Chie Nakajima
  Transactions of the Royal Society of Tropical Medicine and Hygiene, 113, 4, 203, 211, 2019年04月01日, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is an emerging threat for successful tuberculosis control worldwide. Central Asian Strain (CAS) has been reported as one of the dominant families contributing to MDR-TB in South Asia including Nepal, India and Pakistan. The aim of this study was to better understand the genetic characteristics of MDR-TB CAS family isolates circulating in Nepal and compare the results with neighboring countries. METHODS: A total of 145 MDR-TB CAS family isolates collected in Nepal from 2008 to 2013 were analyzed by spoligotyping and mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) analysis. In addition, we compared these data with published data from India and Pakistan to investigate a possible epidemiological link via construction of a minimum spanning tree (MST). RESULTS: Spoligotyping analysis exhibited CAS1_Delhi SIT26 (n=60) as the predominant lineage among the MDR-TB CAS family in all three countries. However, the combined analysis with spoligotyping and MIRU-VNTR further discriminated 60 isolates into 49 different types and 5 clusters. Each cluster was composed of 14 isolates with a clustering rate of 23.3%, suggesting ongoing transmissions. Based on MST data from neighboring countries, we elucidated an evolutionary relationship between the two countries, Nepal and India, which could be explained by their open border. CONCLUSION: This study identified the evolutionary relationships among MDR-TB CAS1_Delhi subfamily isolates from Nepal and those from neighboring countries.
• Ganglioside Synthase Knockout Reduces Prion Disease Incubation Time in Mouse Models.
  Atsushi Kobayashi; Zechen Qi; Taishi Shimazaki; Yoshiko Munesue; Tomomi Miyamoto; Norikazu Isoda; Hirofumi Sawa; Keisuke Aoshima; Takashi Kimura; Shirou Mohri; Tetsuyuki Kitamoto; Tadashi Yamashita; Ichiro Miyoshi
  The American journal of pathology, 189, 3, 677, 686, 2019年03月, ［国際誌］
  英語, 研究論文（学術雑誌）, Localization of the abnormal and normal isoforms of prion proteins to detergent-resistant membrane microdomains, lipid rafts, is important for the conformational conversion. Lipid rafts are enriched in sialic acid-containing glycosphingolipids (namely, gangliosides). Alteration in the ganglioside composition of lipid rafts can affect the localization of lipid raft-associated proteins. To investigate the role of gangliosides in the pathogenesis of prion diseases, we performed intracerebral transmission study of a scrapie prion strain Chandler and a Gerstmann-Sträussler-Scheinker syndrome prion strain Fukuoka-1 using various knockout mouse strains ablated with ganglioside synthase gene (ie, GD2/GM2 synthase, GD3 synthase, or GM3 synthase). After challenge with the Chandler strain, GD2/GM2 synthase knockout mice showed 20% reduction of incubation time, reduced prion protein deposition in the brain with attenuated glial reactions, and reduced localization of prion proteins to lipid rafts. These results raise the possibility that the gangliosides may have an important role in prion disease pathogenesis by affecting the localization of prion proteins to lipid rafts.
• Diversity of spotted fever group rickettsiae and their association with host ticks in Japan.
  Thu MJ; Qiu Y; Matsuno K; Kajihara M; Mori-Kajihara A; Omori R; Monma N; Chiba K; Seto J; Gokuden M; Andoh M; Oosako H; Katakura K; Takada A; Sugimoto C; Isoda N; Nakao R
  Scientific reports, 9, 1, 1500, 1500, 2019年02月06日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, Spotted fever group (SFG) rickettsiae are obligate intracellular Gram-negative bacteria mainly associated with ticks. In Japan, several hundred cases of Japanese spotted fever, caused by Rickettsia japonica, are reported annually. Other Rickettsia species are also known to exist in ixodid ticks; however, their phylogenetic position and pathogenic potential are poorly understood. We conducted a nationwide cross-sectional survey on questing ticks to understand the overall diversity of SFG rickettsiae in Japan. Out of 2,189 individuals (19 tick species in 4 genera), 373 (17.0%) samples were positive for Rickettsia spp. as ascertained by real-time PCR amplification of the citrate synthase gene (gltA). Conventional PCR and sequencing analyses of gltA indicated the presence of 15 different genotypes of SFG rickettsiae. Based on the analysis of five additional genes, we characterised five Rickettsia species; R. asiatica, R. helvetica, R. monacensis (formerly reported as Rickettsia sp. In56 in Japan), R. tamurae, and Candidatus R. tarasevichiae and several unclassified SFG rickettsiae. We also found a strong association between rickettsial genotypes and their host tick species, while there was little association between rickettsial genotypes and their geographical origins. These observations suggested that most of the SFG rickettsiae have a limited host range and are maintained in certain tick species in the natural environment.
• Isolation of Rickettsia, Rickettsiella, and Spiroplasma from Questing Ticks in Japan Using Arthropod Cells.
  Thu MJ; Qiu Y; Kataoka-Nakamura C; Sugimoto C; Katakura K; Isoda N; Nakao R
  Vector borne and zoonotic diseases (Larchmont, N.Y.), 19, 7, 474, 485, 2019年02月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, Ticks are blood-sucking ectoparasites that transmit zoonotic pathogens to humans and animals. Ticks harbor not only pathogenic microorganisms but also endosymbionts. Although some tick endosymbionts are known to be essential for the survival of ticks, their roles in ticks remain poorly understood. The main aim of this study was to isolate and characterize tick-borne microorganisms from field-collected ticks using two arthropod cell lines derived from Ixodes scapularis embryos (ISE6) and Aedes albopictus larvae (C6/36). A total of 170 tick homogenates originating from 15 different tick species collected in Japan were inoculated into each cell line. Bacterial growth was confirmed by PCR amplification of 16S ribosomal DNA (rDNA) of eubacteria. During the 8-week observation period, bacterial isolation was confirmed in 14 and 4 samples using ISE6 and C6/36 cells, respectively. The sequencing analysis of the 16S rDNA PCR products indicated that they were previously known tick-borne pathogens/endosymbionts in three different genera: Rickettsia, Rickettsiella, and Spiroplasma. These included four previously validated rickettsial species namely Rickettsia asiatica (n = 2), Rickettsia helvetica (n = 3), Rickettsia monacensis (n = 2), and Rickettsia tamurae (n = 3) and one uncharacterized genotype Rickettsia sp. LON (n = 2). Four isolates of Spiroplasma had the highest similarity with previously reported Spiroplasma isolates: Spiroplasma ixodetis obtained from ticks in North America and Spiroplasma sp. Bratislava 1 obtained from Ixodes ricinus in Europe, while two isolates of Rickettsiella showed 100% identity with Rickettsiella sp. detected from Ixodes uriae at Grimsey Island in Iceland. To the best of our knowledge, this is the first report on successful isolation of Rickettsiella from ticks. The isolates obtained in this study can be further analyzed to evaluate their pathogenic potential in animals and their roles as symbionts in ticks.
• Genetic diversity and distribution dynamics of multidrug-resistant Mycobacterium tuberculosis isolates in Nepal.
  Bhagwan Maharjan; Chie Nakajima; Norikazu Isoda; Jeewan Thapa; Ajay Poudel; Yogendra Shah; Tomoyuki Yamaguchi; Bhabana Shrestha; Harald Hoffmann; Korkut Avsar; Ashish Shrestha; Stephen V Gordon; Yasuhiko Suzuki
  Scientific reports, 8, 1, 16634, 16634, 2018年11月09日, ［国際誌］
  英語, 研究論文（学術雑誌）, Multidrug-resistant tuberculosis (MDR-TB) is an emerging public health problem in Nepal. Despite the implementation of a successful TB control program in Nepal, notifications of MDR-TB are increasing, yet the reasons are unknown. The objective of this study was to understand the genetic diversity and epidemiological characteristics of MDR-Mycobacterium tuberculosis (MTB) isolates in Nepal. We isolated and genotyped 498 MDR-MTB isolates collected from April 2009 to March 2013 and analyzed the patients' background information. Our results showed that the lineage 2 (Beijing family) was the most predominant lineage (n = 241; 48.4%), followed by lineage 3 (n = 153, 30.7%). Lineage 4 was the third most prevalent (n = 73, 14.5%) followed by lineage 1 (n = 32, 6.4%). The lineages were significantly associated with geographic region, ethnic group, age and sex of patients. The Beijing genotype was found to have an important role in transmitting MDR-TB in Nepal and was significantly associated with the eastern region, mongoloid ethnic group and younger age group. We conclude that early diagnosis and treatment including molecular-epidemiological surveillance of MDR-TB cases will help to control transmission of MDR-TB in Nepal.
• Development of a quick bioassay for the evaluation of transmission properties of acquired prion diseases
  Munesue Y; Shimazaki T; Qi Z; Isoda N; Sawa H; Aoshima K; Kimura T; Mohri S; Kitamoto T; Kobayashi A
  Neurosci Lett, 668, 43, 47, Elsevier BV, 2018年03月, ［査読有り］
  英語, 研究論文（学術雑誌）
• Prevalence of hobi-like viruses in Japan between 2012 and 2017 based on virological methods and serology
  Takashi Kozasa; Shiho Torii; Ken Ichiro Kameyama; Makoto Nagai; Norikazu Isoda; Mai Shiokawa; Hiroshi Aoki; Masatoshi Okamatsu; Hideto Sekiguchi; Akito Saito; Yoshihiro Sakoda
  Japanese Journal of Veterinary Research, 66, 4, 317, 324, 2018年
  研究論文（学術雑誌）
• A cross-sectional study to quantify the prevalence of avian influenza viruses in poultry at intervention and non-intervention live bird markets in central Vietnam, 2014
  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］
  英語, 研究論文（学術雑誌）
• High diversity of multidrug-resistant Mycobacterium tuberculosis Central Asian Strain isolates in Nepal
  Yogendra Shah; Bhagwan Maharjan; Jeewan Thapa; Ajay Poudel; Hassan Mahmoud Diab; Basu Dev Pandey; Eddie S. Solo; Norikazu Isoda; Yasuhiko Suzuki; Chie Nakajima
  INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES, 63, 13, 20, 2017年10月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Oxidative stress and respiratory symptoms due to human exposure to polycyclic aromatic hydrocarbons (PAHs) in Kumasi, Ghana.
  Nesta Bortey-Sam; Yoshinori Ikenaka; Osei Akoto; Shouta M M Nakayama; Kwadwo A Asante; Elvis Baidoo; Christian Obirikorang; Aksorn Saengtienchai; Norikazu Isoda; Collins Nimako; Hazuki Mizukawa; Mayumi Ishizuka
  Environmental pollution (Barking, Essex : 1987), 228, 311, 320, 2017年09月, ［国際誌］
  英語, 研究論文（学術雑誌）, Studies of polycyclic aromatic hydrocarbons (PAHs) and its metabolites in PM10, soils, rat livers and cattle urine in Kumasi, Ghana, revealed high concentrations and cancer potency. In addition, WHO and IARC have reported an increase in cancer incidence and respiratory diseases in Ghana. Human urine were therefore collected from urban and control sites to: assess the health effects associated with PAHs exposure using malondialdehyde (MDA) and 8-hydroxy-2-deoxyguanosine (8-OHdG); identify any association between OH-PAHs, MDA, 8-OHdG with age and sex; and determine the relationship between PAHs exposure and occurrence of respiratory diseases. From the results, urinary concentrations of the sum of OH-PAHs (∑OHPAHs) were significantly higher from urban sites compared to the control site. Geometric mean concentrations adjusted by specific gravity, GMSG, indicated 2-OHNaphthalene (2-OHNap) (6.01 ± 4.21 ng/mL) as the most abundant OH-PAH, and exposure could be through the use of naphthalene-containing-mothballs in drinking water purification, insect repellent, freshener in clothes and/or "treatment of various ailments". The study revealed that exposure to naphthalene significantly increases the occurrence of persistent cough (OR = 2.68, CI: 1.43-5.05), persistent headache (OR = 1.82, CI: 1.02-3.26), tachycardia (OR = 3.36, CI: 1.39-8.10) and dyspnea (OR = 3.07, CI: 1.27-7.43) in Kumasi residents. Highest level of urinary 2-OHNap (224 ng/mL) was detected in a female, who reported symptoms of persistent cough, headache, tachycardia, nasal congestion and inflammation, all of which are symptoms of naphthalene exposure according to USEPA. The ∑OHPAHs, 2-OHNap, 2-3-OHFluorenes, and -OHPhenanthrenes showed a significantly positive correlation with MDA and 4-OHPhenanthrene with 8-OHdG, indicating possible lipid peroxidation/cell damage or degenerative disease in some participants. MDA and 8-OHdG were highest in age group 21-60. The present study showed a significant sex difference with higher levels of urinary OH-PAHs in females than males.
• Evaluation of bovine viral diarrhea virus control strategies in dairy herds in Hokkaido, Japan using stochastic modelling
  Satoshi Sekiguchi; Patrick Presi; Ryosuke Omori; Katharina Stärk; Manon Schuppers; Norikazu Isoda; Yasuhiro Yoshikawa; Takashi Umemura; Hiroyuki Nakayama; Yoshinori Fujii; Yoshihiro Sakoda
  Transboundary and Emerging Diseases, 65, 1, 135, 144, 2017年08月, ［査読有り］
• Evaluation of control measures for bovine viral diarrhea implemented in Nemuro District, Hokkaido, Japan, using a scenario tree model
  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］, ［国内誌］
  英語, 研究論文（学術雑誌）
• Therapeutic efficacy of peramivir against H5N1 highly pathogenic avian influenza viruses harboring the neuraminidase H275Y mutation
  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］
  英語, 研究論文（学術雑誌）
• Molecular epidemiology of pathogenic Leptospira spp. among large ruminants in the Philippines
  Marvin A. Villanueva; Claro N. Mingala; Michelle M. Balbin; Chie Nakajima; Norikazu Isoda; Yasuhiko Suzuki; Nobuo Koizumi
  JOURNAL OF VETERINARY MEDICAL SCIENCE, 78, 11, 1649, 1655, 2016年11月, ［査読有り］, ［国内誌］
  英語, 研究論文（学術雑誌）
• Serological investigation of Leptospira infection and its circulation in one intensive-type water buffalo farm in the Philippines
  Marvin A. Villanueva; Claro N. Mingala; Nina G. Gloriani; Yasutake Yanagihara; Norikazu Isoda; Chie Nakajima; Yasuhiko Suzuki; Nobuo Koizumi
  JAPANESE JOURNAL OF VETERINARY RESEARCH, 64, 1, 15, 24, 2016年02月, ［査読有り］
  英語, 研究論文（学術雑誌）
• Differential potential for envelope glycoprotein-mediated steric shielding of host cell surface proteins among filoviruses
  Osamu Noyori; Keita Matsuno; Masahiro Kajihara; Eri Nakayama; Manabu Igarashi; Makoto Kuroda; Norikazu Isoda; Reiko Yoshida; Ayato Takada
  VIROLOGY, 446, 1-2, 152, 161, 2013年11月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）
• Excessive Cytokine Response to Rapid Proliferation of Highly Pathogenic Avian Influenza Viruses Leads to Fatal Systemic Capillary Leakage in Chickens
  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］
  英語, 研究論文（学術雑誌）
• The nucleoprotein is responsible for intracerebral pathogenicity of A/duck/Mongolia/47/2001 (H7N1) in chicks
  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］
  英語, 研究論文（学術雑誌）
• Recovery of Leptospires from Miniature Pigs Experimentally Infected with Leptospira interrogans Serovar Manilae Strain UP-MMC under Immunosuppressive Conditions by Dexamethasone
  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］
  英語, 研究論文（学術雑誌）
• Purification of human and avian influenza viruses using cellulose sulfate ester (Cellufine Sulfate) in the process of vaccine production
  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］
  英語, 研究論文（学術雑誌）
• Improvement of the H5N1 influenza virus vaccine strain to decrease the pathogenicity in chicken embryos
  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］
  英語, 研究論文（学術雑誌）
• Detection of highly pathogenic avian influenza virus infection in vaccinated chicken flocks by monitoring antibodies against non-structural protein 1 (NS1)
  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］
  英語, 研究論文（学術雑誌）
• Antigenic, genetic, and pathogenic characterization of H5N1 highly pathogenic avian influenza viruses isolated from dead whooper swans (Cygnus cygnus) found in northern Japan in 2008
  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］
  英語, 研究論文（学術雑誌）
• Characterization of H5N1 highly pathogenic avian influenza virus strains isolated from migratory waterfowl in Mongolia on the way back from the southern Asia to their northern territory
  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］
  英語, 研究論文（学術雑誌）
• Novel trivalent anti-influenza reagent
  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］
  英語, 研究論文（学術雑誌）
• Subcutaneous inoculation of a whole virus particle vaccine prepared from a non-pathogenic virus library induces protective immunity against H7N7 highly pathogenic avian influenza virus in cynomolgus macaques
  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］
  英語, 研究論文（学術雑誌）
• Hemagglutinin-Dependent Tropism of H5N1 Avian Influenza Virus for Human Endothelial Cells
  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］
  英語, 研究論文（学術雑誌）
• Generation of congenic mouse strains by introducing the virus-resistant genes, Mx1 and Oas1b, of feral mouse-derived inbred strain MSM/Ms into the common strain C57BL/6J
  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］
  英語, 研究論文（学術雑誌）
• Factors responsible for plaque formation of A/duck/Siberia/272/1998 (H13N6) influenza virus on MDCK cells
  Yoshimi Tsuda; Norikazu Isoda; Yoshihiro Sakoda; Hiroshi Kida
  VIRUS RESEARCH, 140, 1-2, 194, 198, 2009年03月, ［査読有り］
  英語, 研究論文（学術雑誌）
• Evaluation of the potency, optimal antigen level and lasting immunity of inactivated avian influenza vaccine prepared from H5N1 virus
  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］
  英語, 研究論文（学術雑誌）
• Antigenic structure of the hemagglutinin of H9N2 influenza viruses
  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］
  英語, 研究論文（学術雑誌）
• Antigenic and genetic analysis of H5 influenza viruses isolated from water birds for the purpose of vaccine use
  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］
  英語, 研究論文（学術雑誌）
• Phylogenic analysis of the M genes of influenza viruses isolated from free-flying water birds from their Northern Territory to Hokkaido, Japan
  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］
  英語, 研究論文（学術雑誌）
• Phylogenic analysis of the M genes of influenza viruses isolated from free-flying water birds from their Northern Territory to Hokkaido, Japan (Virus Genes DOI: 10.1007/s11262-008-0248-7)
  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］
  英語, 研究論文（学術雑誌）
• Potency of an inactivated avian influenza vaccine prepared from a non-pathogenic H5N1 reassortant virus generated between isolates from migratory ducks in Asia
  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］
  英語, 研究論文（学術雑誌）
• H2N5 influenza virus isolates from terns in Australia: genetic reassortants between those of the Eurasian and American lineages
  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］
  英語, 研究論文（学術雑誌）
• Induction of cytotoxic T-lymphocyte and antibody responses against highly pathogenic avian influenza virus infection in mice by inoculation of apathogenic H5N1 influenza virus particles inactivated with formalin
  Toshihiro Sawai; Yasushi Itoh; Hiroichi Ozaki; Norikazu Isoda; Kiyoko Okamoto; Yoshitaka Kashima; Yoshihiro Kawaoka; Yoshihiro Takeuchi; Hiroshi Kida; Kazumasa Ogasawara
  IMMUNOLOGY, 124, 2, 155, 165, 2008年06月, ［査読有り］
  英語, 研究論文（学術雑誌）
• A vaccine prepared from a non-pathogenic H7N7 virus isolated from natural reservoir conferred protective immunity against the challenge with lethal dose of highly pathogenic avian influenza virus in chickens
  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］
  英語, 研究論文（学術雑誌）
• Development of vaccine strains of H5 and H7 influenza viruses
  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］
  英語, 研究論文（学術雑誌）
• Pathogenicity of a highly pathogenic avian influenza virus, A/chicken/Yamaguchi/7/04 (H5N1) in different species of birds and mammals.
  N Isoda; Y Sakoda; N Kishida; G-R Bai; K Matsuda; T Umemura; H Kida
  Archives of virology, 151, 7, 1267, 79, 2006年07月, ［国際誌］
  英語, 研究論文（学術雑誌）, 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.
• Pathogenicity of H5 influenza viruses for ducks
  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］
  英語, 研究論文（学術雑誌）

• 2024~2025年における野鳥および海生哺乳類のHPAIV感染の確認とモニタリング体制で見えてきた課題
  渡辺有希子; 安達光; 服部薫; 松野啓太; 日尾野隆大; 日尾野隆大; 直亨則; 磯田典和; 磯田典和; 迫田義博; 迫田義博; 大沼学; 齊藤慶輔, 北海道獣医師会雑誌, 69, 8, 2025年
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  磯田典和; 磯田典和; 磯田典和; 磯田典和; 関口敏; 関口敏; HUNG Ngo Dinh; HUNG Ngo Dinh; 龍千香; 牛谷雄一; 野津昂亮; 濱口華凜; 小林茉弥; 日尾野隆大; 迫田義博; 日尾野隆大; 迫田義博; 日尾野隆大; 迫田義博; 日尾野隆大; 迫田義博, 日本獣医学会学術集会講演要旨集, 167th, 2024年
• ノイラミニダーゼストーク領域におけるN型糖鎖欠損がH7N7高病原性鳥インフルエンザウイルスのニワトリに対する病原性を高める
  小林大樹; 日尾野隆大; 日尾野隆大; 日尾野隆大; 日尾野隆大; 荒川広夢; 梶裕之; 大河原彩子; 市川貴也; 伴日向子; 磯田典和; 迫田義博; 磯田典和; 迫田義博; 磯田典和; 迫田義博; 磯田典和; 迫田義博, 日本獣医学会学術集会講演要旨集, 167th, 2024年
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  七戸新太郎; 日尾野隆大; 日尾野隆大; 日尾野隆大; 下岡誠; 磯田典和; 磯田典和; 磯田典和; 迫田義博; 迫田義博; 迫田義博; 迫田義博; 渡辺登喜子; 渡辺登喜子; 渡辺登喜子, 日本ウイルス学会学術集会プログラム・予稿集(Web), 71st, 2024年
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  島津陽; 三木万梨子; 尾原涼; 中谷裕美子; 長嶺隆; 吉本悠人; 林万里菜; 井出いづみ; 見浦沙耶子; 平栗祐子; 加来雅人; 豊田恒介; 尾崎美樹; 日尾野隆大; 日尾野隆大; 磯田典和; 磯田典和; 宍戸貴雄; 池中良徳; 迫田義博; 迫田義博, 日本野生動物医学会大会・講演要旨集, 30th, 2024年
• 非臨床モデルでのバロキサビル マルボキシル投与経路の検討~ヤンバルクイナにおける吸収性改善を目指して~
  三木万梨子; 島津陽; 尾原涼; 大崎裕美; 宍戸貴雄; 池中良徳; 木村享史; 日尾野隆大; 日尾野隆大; 磯田典和; 磯田典和; 迫田義博; 迫田義博, 日本野生動物医学会大会・講演要旨集, 30th, 2024年
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  伊藤聡; 伊藤聡; AGUILAR-VEGA Cecilia; BOSCH Jaime; 磯田典和; 磯田典和; SANCHEZ-VIZCAINO Jose Manuel, 獣医疫学雑誌, 28, 1, 2024年
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  日尾野隆大; 日尾野隆大; 日尾野隆大; 磯田典和; 磯田典和; 磯田典和; 磯田典和; 迫田義博; 迫田義博; 迫田義博; 迫田義博, 人と動物の共通感染症研究会学術集会講演要旨集(Web), 23rd, 2023年
• 豚熱発生県における発生・未発生農場の農場衛生対策実施状況の比較
  浮田真琴; 磯田典和; 山本健久; 蒔田浩平, 獣医疫学雑誌, 26, 1, 2022年
• 国内で流行している牛ウイルス性下痢ウイルスは,遺伝子型1bおよび2aが主流である
  西森朝美; 安藤清彦; 迫田義博; 磯田典和; 廣瀬静香; 荻野紗帆, 農研機構動物衛生研究部門成果情報(Web), 2021, 2021年
• シミュレーションモデルによるCSF母豚抗体価の世代別推移の予測
  浮田真琴; 桑田桂輔; 田中英次; 磯田典和; 迫田義博; 蒔田浩平, 獣医疫学雑誌, 25, 1, 2021年
• 高病原性鳥インフルエンザウイルスの自然感染が確認されたオジロワシの事例
  小笠原浩平; 藤本佳万; 畑井仁; 磯田典和; 渡辺有希子; 大沼学; 小澤真; 迫田義博; 齊藤慶輔, 北海道獣医師会雑誌, 65, 8, 2021年
• 豚熱農場ワクチン開始時期に基づくシミュレーションモデルによる地域別ワクチンプログラムの検討
  浮田真琴; 桑田桂輔; 田中英次; 磯田典和; 迫田義博; 蒔田浩平, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
• 2014年から2020年に日本で分離された牛ウイルス性下痢ウイルスの遺伝子解析
  荻野紗帆; 西森朝美; 廣瀬静香; 磯田典和; 磯田典和; 日尾野隆大; 安藤清彦; 迫田義博; 迫田義博, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
• シチメンチョウの気管上皮に発現する多様な鳥インフルエンザウイルスレセプターの構造解析
  小林大樹; 市居修; 日尾野隆大; 西原祥子; 高瀬明; 磯田典和; 磯田典和; 迫田義博; 迫田義博, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
• 2020年度冬季に東日本の野鳥から分離された高病原性鳥インフルエンザウイルスの性状
  磯田典和; 磯田典和; 日尾野隆大; TWABELA Augustin T.; BAZARRAGCHAA Enkhbold; KIEN Le Trung; LOC Huynh Tan; 小笠原浩平; 林裕貴; 渡辺有希子; 齊藤慶輔; 喜田宏; 迫田義博; 迫田義博, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
• アミノレブリン酸リン酸塩による豚熱ウイルス増殖抑制効果の検証
  廣瀬静香; LOC Huynh Tan; 金琢珠; 磯田典和; 磯田典和; 日尾野隆大; 吉本圭一郎; 田中徹; 乾健二郎; 迫田義博; 迫田義博, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
• ワクチンシードと同じアミノ酸配列を持つ豚熱ウイルスGPE^-株作出の試み
  金琢洙; LOC Huynh Tan; 廣瀬静香; 日尾野隆大; 磯田典和; 磯田典和; 迫田義博; 迫田義博, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
• レポーターとして発光HiBiTタグを有する組換え高病原性古典的ブタ熱ウイルス株の生成【JST・京大機械翻訳】
  LOC Huynh Tan; 廣瀬静香; 金琢洙; 田村友和; 福原崇介; 松浦善治; 日尾野隆大; 磯田典和; 磯田典和; 迫田義博; 迫田義博, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
• インフルエンザウイルスライブラリーを活用したパンデミックインフルエンザ対策
  野村直樹; 新開大史; 松野啓太; 関屋俊輝; 関屋俊輝; 大野円実; 磯田典和; 迫田義博; 喜田宏; 喜田宏, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
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  LE Trung Kien; 磯田典和; 磯田典和; NGUYEN Thanh Lam; NGUYEN Thanh Lam; CHU Duc-Huy; TIEN Ngoc Tien; LE Thanh Tung; 日尾野隆大; 迫田義博; 迫田義博, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
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  迫田義博; 迫田義博; 遠藤真由美; 伊藤貢; 日尾野隆大; 磯田典和; 磯田典和, 日本獣医学会学術集会講演要旨集, 164th (CD-ROM), 2021年
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  迫田義博; 迫田義博; 遠藤真由美; 伊藤貢; 日尾野隆大; 磯田典和; 磯田典和, 家畜衛生学雑誌, 47, 3, 2021年
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  林裕貴; 岡松正敏; 小笠原帆南; 津川尚子; 磯田典和; 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, 163rd, 2020年
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  磯田典和; 浅野明弘; 一條満; 大野浩; 佐藤一彦; 岡本浩一; 中尾茂; 加藤肇; 斉藤一真; 伊藤直樹; 臼井章; 高山裕章; 迫田義博, 北海道獣医師会雑誌, 62, 8, 353, 353, 2018年08月24日
  (公社)北海道獣医師会, 日本語
• 2014-2017のベトナムにおけるH5高病原性鳥インフルエンザ発生の時空間・リスク解析(Spatiotemporal and risk analysis of H5 highly pathogenic avian influenza occurrence in Vietnam during 2014-2017)
  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
  (公社)日本獣医学会, 英語
• インフルエンザに立ち向かう 人獣共通感染症としてのインフルエンザ
  磯田典和; 高田礼人, Mebio, 30, 12, 32, 41, 2013年12月10日
  日本語, 記事・総説・解説・論説等（学術雑誌）
• フィロウイルス糖蛋白質による宿主細胞表面分子の立体的遮蔽現象の解析
  野依修; 松野啓太; 梶原将大; 中山絵里; 五十嵐学; 磯田典和; 吉田玲子; 高田礼人, 日本ウイルス学会学術集会プログラム・抄録集, 60th, 198, 2012年10月31日
  日本語
• 高病原性鳥インフルエンザの予防対策
  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
  農林水産技術情報協会, 日本語
• H5亜型ウイルスに対する鳥インフルエンザワクチンの開発 : 高力価のワクチンを開発. H7ウイルス用もスタンバイ
  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
  社団法人 日本農芸化学会, 日本語
• 国内開発鳥インフルエンザワクチン
  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
  鶏病研究会, 日本語
• 2008年北海道で発見された斃死オオハクチョウから分離したH5N1高病原性鳥インフルエンザウイルスの性状
  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
  日本語
• 2008年北海道で発見された斃死オオハクチョウから分離したH5N1高病原性鳥インフルエンザウイルスの性状
  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
  日本語
• Concentration and purification of influenza viruses by sulfate ester of cellulose (Cellufine Sulfate (R))
  Kouichi Ozaki; Yasuto Umeda; Shigeyuki Aoyama; Norikazu Isoda; Masatoshi Okamatsu; Yoshihiro Sakoda, VACCINE, 2008年
  英語, 研究発表ペーパー・要旨（国際会議）
• 動物インフルエンザのグローバルサーベイランスと全ての亜型ウイルスライブラリーの構築
  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
  日本語
• 鳥インフルエンザに対するワクチンの開発
  磯田 典和; 喜田 宏, ファームステージ, 7, 6, 84, 87, 2007年09月
  技術情報協会, 日本語
• 動物インフルエンザのグローバルサーベイランスと全ての亜型ウイルスライブラリーの構築
  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
  日本語

• 日本および世界で今冬報告された鳥インフルエンザウイルス
  磯田典和
  第57回獣医疫学会, 2021年03月20日, 口頭発表（招待・特別）
• 時空間解析を用いた日本における野生イノシシ群での豚コレラ感染拡大評価
  磯田典和; 馬場開陸; 伊藤聡; 伊藤貢; 迫田義博; 蒔田浩平
  第56回獣医疫学会, 2020年09月05日, 口頭発表（一般）
• 日本における牛ウイルス性下痢症に対する着地検査およびバルク乳検査の費用対効果
  磯田典和; 浅野明弘; 一條満; 大野浩; 佐藤一彦; 岡本浩一; 中尾茂; 加藤肇; 斉藤一真; 伊藤直樹; 臼井章; 高山裕章; 迫田義博
  平成30年度北海道獣医師会地区学会, 2018年08月27日, 口頭発表（一般）
• Assessment of antimicrobial resistant Enterobacteriaceae in pigs for development of comprehensive management system
  Norikazu Isoda
  Philippine Society of Animal science, 英語, 口頭発表（招待・特別）
  ［招待講演］

• 産業動物獣医療実習Ⅱ, 2024年, 学士課程, 獣医学部
• 大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
• 大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
• 生物統計学特論, 2024年, 博士後期課程, 獣医学院
• 生物統計学特論, 2024年, 博士後期課程, 国際感染症学院
• 国際保健衛生演習, 2024年, 博士後期課程, 国際感染症学院
• 国際協力機関特論, 2024年, 博士後期課程, 獣医学院
• 国際協力機関特論, 2024年, 博士後期課程, 国際感染症学院
• リスク分析学特論, 2024年, 博士後期課程, 国際感染症学院
• 越境性感染症学特論, 2024年, 博士後期課程, 国際感染症学院
• 人獣共通感染症対策専門特論, 2024年, 博士後期課程, 国際感染症学院
• 産業動物獣医療実習Ⅱ, 2024年, 学士課程, 獣医学部
• 微生物学実習, 2024年, 学士課程, 獣医学部
• 獣医疫学演習, 2024年, 学士課程, 獣医学部
• 動物衛生学実習, 2024年, 学士課程, 獣医学部
• アドバンスト演習, 2024年, 学士課程, 獣医学部

• 肉用牛における牛ウイルス性下痢のリスク要因の特定および疾病モデルの樹立
  科学研究費助成事業
  2022年04月01日 - 2025年03月31日
  磯田 典和
  日本学術振興会, 基盤研究(C), 北海道大学, 22K06019
• 動物の移動およびワクチン接種が牛ウイルス性下痢症の導入リスクに与える影響
  科学研究費助成事業 基盤研究(C)
  2019年04月01日 - 2022年03月31日
  磯田 典和
  2019年度に実施を予定していた、移動履歴有無によるPI牛のコホート調査（実験1）および耳片組織材料を用いた診断感度の確認（実験2）について、未だ実施できていない。これは、当初調査を予定していた地方行政機関との協力が難しくなったことに起因しており、事態が変化した背景として、2018年より本邦にて発生している豚熱の流行が挙げられる。
  それを受けて、2019年度はこれら野外フィールドでの疫学調査に協力いただける機関を、今までの研究で得られたネットワークを生かして探していたところ、2020年3月現在で、研究協力を前向きに検討していただける協力機関を見つけることができた。現在は先方での内部調整の結果を待ってはいるが、2020年8月から2021年3月までの期間にて、1)ならびに2)の実験を実施する予定でいる。
  当初2019年度に予定していた疫学調査の実施であったが、上記の理由で実施できなかった。しかしながら、2019年度の終わりに研究の協力が可能な機関が見つかったため、2020年度の疫学調査実施のための診断試薬の購入や材料採取道具の用意を進めた。また研究協力機関に出張し、当方の研究計画の紹介および牛ウイルス性下痢症の現状や対策について意見交換も行った。
  野外フィールド調査の実施調整だけではなく、2019年度は、当初協力予定期間から分与頂いた血清中の抗体データを用い、ワクチン接種された牛群における牛ウイルス性下痢症のリスクについて評価を行った。当初の予定にはなかったが、これらデータから得られる知見も当初の目的を遂行するために有用であるため、これらデータ解析をまとめ報告する予定である。
  日本学術振興会, 基盤研究(C), 北海道大学, 19K06377
• 高病原性鳥インフルエンザワクチン株の樹立とヒト用ワクチンへの応用
  科学研究費助成事業
  2007年 - 2007年
  磯田 典和
  日本では、高病原性鳥インフルエンザ(HPAI)の防疫対策としては摘発淘汰を基本とし、防圧が困難な非常時に備え、高力価のワクチンを備蓄しておく方針が採られている。そこで野生水禽から分離された2株の非病原性鳥インフルエンザウイルスの遺伝子再集合体H5N1ウイルス株を鶏胚で培養不活化し、生物製剤基準に準じてワクチンを試製した。本ワクチンを接種したニワトリをHPAIウイルスで攻撃し、免疫効果を評価した。攻撃株として、2004年山口県で発生したHPAIの病原ウイルスであるA/chicken/Yamaguchi/7/04(H5N1)およびモンゴル国で発見されたオオハクチョウの斃死体から分離されたHPAIウイルス、A/whooper swan/Mongolia/3/05(H5N1)株を用いた。いずれの場合もニワトリは臨床症状を示すことなく耐過した。作製したワクチンの効果発現日数を測定したところ、ワクチン接種後6日以内のニワトリは攻撃ウイルスにより全て死亡したが、ワクチン接種8日目のニワトリはHI抗体が検出されないにも拘わらず、HPAIウイルスの攻撃に対して耐過した。ワクチン接種後6ケ月のニワトリにおいても、HPAIウイルスの攻撃に十分耐過できる抗体価を有していることも確認された。これらの結果から、本ワクチンは日本国における鳥インフルエンザの緊急用備蓄ワクチンとして利用し得ることが明らかになった。以上の研究を踏まえ、ワクチン株の改良を主眼とした研究を引き続き行った。ワクチン株である、A/duck/Hokkaido/Vac-1/04(H5N1)(Dk/Vac-1/04)株は、静脈内接種によりニワトリに対して非病原性と判定されたが、鶏胚に対して中等度の病原性を示すことから、製造効率では不十分であることが示唆された。そこで、Dk/Vac-1/04株の鶏胚に対する病原性を決定する遺伝子を同定することを目的とした人工作出ウイルスを9日齢発育鶏卵の尿膜腔内に接種し、8時間毎にその生死を観察して、鶏胚の平均致死時間を算出したところ、PB1遺伝子およびPA遺伝子が鶏胚に対する病原性に関与することが判った。
  日本学術振興会, 特別研究員奨励費, 北海道大学, 07J52013