研究者データベース

佐鹿 万里子(サシカ マリコ)
獣医学研究院 獣医学部門 環境獣医科学分野
助教

基本情報

所属

  • 獣医学研究院 獣医学部門 環境獣医科学分野

職名

  • 助教

学位

  • 獣医学博士

J-Global ID

研究キーワード

  • タヌキ   中型哺乳類   外来種   アライグマ   野生動物の感染症   

研究分野

  • ライフサイエンス / 獣医学 / 外来種、アライグマ、中型哺乳類、タヌキ、生態学、感染症

研究活動情報

論文

  • Ryo Nakao, Kohei Shinjo, Tomoki Sakiyama, Shohei Ogata, Kodai Kusakisako, Gohta Kinoshita, Doaa Naguib, Elisha Chatanga, Wessam Mohamed Ahmed Mohamed, Mohamed Abdallah Mohamed Moustafa, Keita Matsuno, Takuya Ito, Nariaki Nonaka, Mariko Sashika, Toshio Tsubota, Michito Shimozuru
    Parasitology international 80 102209 - 102209 2021年02月 [査読有り]
     
    The tick Amblyomma testudinarium Koch, 1844 (Acari: Ixodidae) is known as a vector of several pathogens such as Rickettsia tamurae and severe fever with thrombocytopenia syndrome (SFTS) virus. This tick species is present in many Asian countries, including Japan, where its distribution is limited to the warm areas of Kanto region and the southwestern region. The present study reports the recovery of a partially engorged A. testudinarium from a wild brown bear captured in Shari town, Hokkaido. In addition to morphological identification, the specimen was genetically characterized by the complete mitochondrial genome sequencing. The results showed that the length of the obtained mitogenome is 14,835 bp that encodes 13 protein-coding, two ribosomal RNA (rRNA) (12S and 16S), and 22 transfer RNA genes with two non-coding control regions. The phylogenetic analysis indicated that our sample clustered with A. testudinarium from Nara, Japan, but separated from A. testudinarium from China. Although the introduction of the tick through livestock transportation cannot be ruled out, the detection of A. testudinarium in Hokkaido prefecture, which is separated from the main island where A. testudinarium is present in the south, may suggest the introduction by migratory birds. This study provides important insights on the distribution and host range of A. testudinarium. This will be useful for the future taxonomic analysis of ticks based on the complete mitogenome sequencing. To our knowledge, this is the northernmost detection point of the tropical tick A. testudinarium.
  • Sakura Oe, Mariko Sashika, Ayako Fujimoto, Michito Shimozuru, Toshio Tsubota
    Scientific Reports 10 1 2020年12月 [査読有り]
     
    AbstractIn Japan, there are concerns that invasive alien raccoons prey on rare native species during their spawning season from late winter to early summer. We investigated raccoon predation impact by examining the predation presence using DNA metabarcoding and extent of predation on rare native species using stable isotope analysis. We captured raccoons in Hokkaido, Japan from April to August in 2018 and 2019. We analysed raccoon faeces and gastric contents by DNA metabarcoding to detect the rare native Hokkaido salamander and Japanese crayfish. Hokkaido salamanders were detected from gastric contents, but Japanese crayfish were not detected in any samples. Stable isotope analysis of raccoon muscle samples and the Bayesian mixing model were used to estimate each food resource’s contribution to the raccoon diet. Animal food resources accounted for 70% of total consumed food. The foraging ratios of amphibians and crustaceans were about 9% and 5%, respectively. Raccoons have been found to use amphibians at a higher rate than previously reported, including a rare endangered species, the Hokkaido salamander. Hokkaido salamander and Japanese crayfish spawn in the spring, and increased predation pressure by raccoons may directly impact populations of these rare native species.
  • Mohamed Abdallah Mohamed Moustafa, Ayaka Sasaki, Michito Shimozuru, Ryo Nakao, Mariko Sashika, Koji Yamazaki, Shinsuke Koike, Junpei Tanaka, Hiroo Tamatani, Masami Yamanaka, Tsuyoshi Ishinazaka, Toshio Tsubota
    Parasitology research 119 11 3739 - 3753 2020年11月 [査読有り]
     
    Many tick-borne pathogens (TBPs) are present in wildlife. The objective of this study is to reveal the role of wild bears in maintaining TBPs. A total of 49 brown bears (Ursus arctos yesoensis) from Hokkaido, and 18 Japanese black bears (Ursus thibetanus japonicus) from Tochigi, and 66 Japanese black bears from Nagano were examined by two molecular methods, reverse line blot (RLB) hybridization, and nested PCR. A total of 5 TBPs (Hepatozoon ursi, Babesia sp. UR2-like group, Cytauxzoon sp. UR1, Babesia sp. UR1, and Babesia microti) were detected from bear blood DNA samples. B. microti was detected from blood DNA samples of Japanese black bear for the first time, with the prevalence of 6.0% (5/84). Out of detected pathogens, H. ursi, Babesia sp. UR2-like pathogens, and Cytauxzoon sp. UR1 were considered as three of the most prevalent TBPs in bears. The prevalence of H. ursi were significantly higher in Japanese black bear (0% vs 96.4%) while that of Babesia sp. UR2-like group was higher in Hokkaido brown bears (89.8% vs 40.5%). The prevalence of Babesia sp. UR1 were significantly higher in Japanese black bears from Tochigi (44.4%), comparing with those from Nagano (18.2%). The prevalence of the detected TBPs were significantly higher in adult bears, comparing with those in younger bears. The present study suggests that Japanese bear species contribute in the transmission of several TBPs in Japan. The expanding distribution of bears might cause the accidental transmission of TBPs to humans and domestic animals.
  • Elzahara Elbaz, Mohamed Abdallah Mohamed Moustafa, Kyunglee Lee, Alice Lau Ching Ching, Michito Shimozuru, Mariko Sashika, Ryo Nakao, Sabry Ahmed El-Khodery, Toshio Tsubota
    Experimental & applied acarology 82 3 411 - 429 2020年11月 [査読有り]
     
    Ticks are hematophagous ectoparasites that have a significant impact on their animal hosts. Along with mosquitoes, they are the main arthropod vectors of disease agents in domestic animals, wildlife and humans. To investigate the occurrence and prevalence of piroplasmids in ticks, DNA was extracted from 519 hard ticks collected from 116 hunted Hokkaido sika deer (Cervus nippon yesoensis). The success of the DNA extraction was confirmed by touchdown PCR targeting the mitochondrial 16S rDNA gene of ticks. Touchdown PCR and reverse line blot (RLB) hybridization targeting the 18S rRNA gene were used to detect 14 piroplasm species. All hard ticks parasitizing Hokkaido sika deer were identified as belonging to the genera Ixodes and Haemaphysalis. In total 163 samples (31.4%) were positive for Babesia and Theileria spp. among tick species according to RLB hybridization. Tick DNA hybridized to the oligonucleotide probes of Theileria sp. Thrivae (27.0% of ticks; 140/519), Theileria capreoli (10.6%; 55/519), Babesia divergens-like (1.7%; 9/519), Babesia sp. (Bab-SD) (0.6%; 3/519), Babesia microti U.S. (0.4%; 2/519), and B. microti Hobetsu (0.4%; 2/519). The partial sequencing and phylogenetic analyses of the 18S rRNA gene confirmed the RLB hybridization results. Further investigations are needed to reveal the epidemiology and respective vectors of these pathogens.
  • Alireza Nasoori, Yuko Okamatsu-Ogura, Michito Shimozuru, Mariko Sashika, Toshio Tsubota
    PloS one 15 8 e0238132  2020年 [査読有り]
     
    Bears do not suffer from osteoporosis during hibernation, which is associated with long-term inactivity, lack of food intake, and cold exposure. However, the mechanisms involved in bone loss prevention have scarcely been elucidated in bears. We investigated the effect of serum from hibernating Japanese black bears (Ursus thibetanus japonicus) on differentiation of peripheral blood mononuclear cells (PBMCs) to osteoclasts (OCs). PBMCs collected from 3 bears were separately cultured with 10% serum of 4 active and 4 hibernating bears (each individual serum type was assessed separately by a bear PBMCs), and differentiation were induced by treatment with macrophage colony stimulating factor (M-CSF) and receptor activator of NF-kB ligand (RANKL). PBMCs that were cultured with the active bear serum containing medium (ABSM) differentiated to multi-nucleated OCs, and were positive for TRAP stain. However, cells supplemented with hibernating bear serum containing medium (HBSM) failed to form OCs, and showed significantly lower TRAP stain (p < 0.001). On the other hand, HBSM induced proliferation of adipose derived mesenchymal stem cells (ADSCs) similarly to ABSM (p > 0.05), indicating no difference on cell growth. It was revealed that osteoclastogenesis of PBMCs is hindered by HBSM, implying an underlying mechanism for the suppressed bone resorption during hibernation in bears. In addition, this study for the first time showed the formation of bears' OCs in-vitro.
  • Yuri Shirane, Fumihiko Mori, Masami Yamanaka, Masanao Nakanishi, Tsuyoshi Ishinazaka, Tsutomu Mano, Mina Jimbo, Mariko Sashika, Toshio Tsubota, Michito Shimozuru
    PeerJ 8 e9982  2020年 [査読有り]
     
    Body condition is an important determinant of health, and its evaluation has practical applications for the conservation and management of mammals. We developed a noninvasive method that uses photographs to assess the body condition of free-ranging brown bears (Ursus arctos) in the Shiretoko Peninsula, Hokkaido, Japan. First, we weighed and measured 476 bears captured during 1998-2017 and calculated their body condition index (BCI) based on residuals from the regression of body mass against body length. BCI showed seasonal changes and was lower in spring and summer than in autumn. The torso height:body length ratio was strongly correlated with BCI, which suggests that it can be used as an indicator of body condition. Second, we examined the precision of photograph-based measurements using an identifiable bear in the Rusha area, a special wildlife protection area on the peninsula. A total of 220 lateral photographs of this bear were taken September 24-26, 2017, and classified according to bear posture. The torso height:body/torso length ratio was calculated with four measurement methods and compared among bear postures in the photographs. The results showed torso height:horizontal torso length (TH:HTL) to be the indicator that could be applied to photographs of the most diverse postures, and its coefficient of variation for measurements was <5%. In addition, when analyzing photographs of this bear taken from June to October during 2016-2018, TH:HTL was significantly higher in autumn than in spring/summer, which indicates that this ratio reflects seasonal changes in body condition in wild bears. Third, we calculated BCI from actual measurements of seven females captured in the Rusha area and TH:HTL from photographs of the same individuals. We found a significant positive relationship between TH:HTL and BCI, which suggests that the body condition of brown bears can be estimated with high accuracy based on photographs. Our simple and accurate method is useful for monitoring bear body condition repeatedly over the years and contributes to further investigation of the relationships among body condition, food habits, and reproductive success.
  • Epidemiological study of sarcoptic mange in raccoon dogs (Nyctereutes procyonoides albus) in Hokkaido, Japan
    Sashika M, Abe G, Nakai M, Osaki A, Fujimoto A, Tsubota T
    Japanese Journal of Veterinary Research 67 4 253 - 261 2019年11月 [査読有り][通常論文]
  • Aya Osaki, Mariko Sashika, Go Abe, Kohei Shinjo, Ayako Fujimoto, Mariko Nakai, Michito Shimozuru, Toshio Tsubota
    BMC ecology 19 1 35 - 35 2019年09月11日 [査読有り][通常論文]
     
    BACKGROUND: In Japan, invasive raccoons cause severe ecological and social problems by transmitting pathogens to humans, livestock, and native species, causing substantial crop damage, and competing with native species. Possible competition between invasive raccoons and native raccoon dogs is of concern in Japan because Japanese raccoon dogs have a limited distribution and are native only to Japan and the two species have similar characteristics. We assessed potential competition between raccoons and raccoon dogs by comparing feeding habits and habitat use. RESULTS: Both species were captured in Hokkaido, Japan from 2004 to 2017. More raccoons were captured close to agricultural land at the forest periphery (70.1%, 358/511); conversely, more raccoon dogs were captured in the forest core (74.9%, 253/338). Feeding habits were then examined by fecal analysis and stable isotope analyses. Fecal analysis revealed both species to be opportunistic omnivores that consumed easily found food items. However, raccoon feces contained more crops, whereas raccoon dog feces contained more insects, reflecting the different locations in which the species were trapped. Moreover, stable isotope ratios were significantly higher in raccoons than raccoon dogs (Corn has the highest carbon stable isotope (δ13C) value, and amphibians and reptiles are high in nitrogen stable isotope (δ15N); forest resources such as insects and wild fruits are low in δ13C and δ15N). CONCLUSIONS: We conclude that both species ate similar food types, but their food preferences appeared to differ. Raccoon and raccoon dog habitat use also differed, possibly because the two species inhabited areas where they could easily obtain their preferred foods. Therefore, the current feeding habits and habitat use of raccoons do not appear to overlap sufficiently with those of raccoon dogs to impact the latter. The results of this study, particularly the stable isotope data, may provide a useful precedent for future studies of competition in medium-sized mammals, particularly canids.
  • Shirane, Yuri, Shimozuru, Michito, Yamanaka, Masami, Tsuruga, Hifumi, Nakanishi, Masanao, Ishinazaka, Tsuyoshi, Nose, Takane, Kasai, Shinsuke, Shirayanagi, Masataka, Masuda, Yasushi, Fujimoto, Yasushi, Mano, Tsutomu, Sashika, Mariko, Tsubota, Toshio
    JOURNAL OF MAMMALOGY 100 4 1317 - 1326 2019年07月 [査読有り][通常論文]
     
    Natal dispersal likely plays an important role in avoiding inbreeding among large carnivores. We tested the hypothesis that male-biased dispersal reduces close inbreeding by limiting the spatial overlap of opposite-sex pairs of close relatives in brown bears (Ursus arctos) in the Shiretoko Peninsula, Hokkaido, Japan. We genotyped 837 individuals collected in 1998-2017 at 21 microsatellite loci and performed parentage analysis. To calculate natal dispersal distance, we considered the site where the mother was identified as the birthplace of her offspring, and the site where the offspring were identified as their dispersed place. As predicted, we found that dispersal distances were significantly greater for males (12.4 km +/- 1.0) than for females (7.7 km +/- 0.9), and those for males increased from 3 years old, indicating that males begin to disperse around the time sexual maturation begins. Relatedness decreased with distance among pairs of females, and the mean relatedness was significantly higher between pairs of females than between pairs of males or between female-male pairs within 3 km. Closely related female-male pairs rarely (5-6%) resided in close proximity (< 3 km), compared with pairs of closely related females. Our study revealed that the potential for close inbreeding was low in Hokkaido brown bears because males are effective dispersers.
  • Paudel S, Nakajima C, Mikota SK, Gairhe KP, Maharjan B, Subedi S, Poudel A, Sashika M, Shimozuru M, Suzuki Y, Tsubota T
    Emerging infectious diseases 25 5 1031 - 1032 2019年05月 [査読有り][通常論文]
  • Shiho Torii, Keita Matsuno, Yongjin Qiu, Akina Mori-Kajihara, Masahiro Kajihara, Ryo Nakao, Naganori Nao, Katsunori Okazaki, Mariko Sashika, Takahiro Hiono, Masatoshi Okamatsu, Yoshihiro Sakoda, Hideki Ebihara, Ayato Takada, Hirofumi Sawa
    Ticks and tick-borne diseases 10 2 328 - 335 2019年02月 [査読有り][通常論文]
     
    Recent discoveries of tick-borne pathogens have raised public health concerns on tick-borne infectious diseases and emphasize the need to assess potential risks of unrecognized tick-borne pathogens. First, to determine the existence of tick-borne phleboviruses (TBPVs), genetic surveillance of phleboviruses in ticks was conducted mainly in Hokkaido, the northernmost island in Japan from 2013 to 2015. Genes of two TBPVs, previously reported as Mukawa virus (MKWV) and a newly identified relative of MKWV, Kuriyama virus (KURV), were detected and the viruses were isolated from Ixodes persulcatus collected in Hokkaido, but not in I. persulcatus collected from other areas of Japan. These viruses were phylogenetically and antigenically similar to each other. Next, to investigate the infection of MKWV in mammals, serum samples from wildlife captured in Hokkaido from 2007 to 2011 were used for serological screening. Neutralizing antibodies against MKWV were detected in both Yezo-deer (Cervus nippon yesoensis) (2/50) and raccoons (Procyon lotor) (16/64). However, no infectious MKWV was recovered from laboratory mice in experimental infections, though viral RNAs were detected in their tissues. Thus, MKWV and KURV may maintain tick-mammalian life cycles in Hokkaido, suggesting their potential as causative agents of tick-borne diseases in mammals.
  • Shirane Yuri, Shimozuru Michito, Yamanaka Masami, Tsuruga Hifumi, Hirano Saiko, Nagano Natsuo, Moriwaki Jun, Nakanishi Masanao, Ishinazaka Tsuyoshi, Nose Takane, Kasai Shinsuke, Shirayanagi Masataka, Masuda Yasushi, Fujimoto Yasushi, Osada Masahiro, Akaishi Masao, Mano Tsutomu, Masuda Ryuichi, Sashika Mariko, Tsubota Toshio
    EUROPEAN JOURNAL OF WILDLIFE RESEARCH 64 6 65  2018年12月 [査読有り][通常論文]
  • Yoonjee Hong, Kyung Seok Kim, Junpei Kimura, Kaarina Kauhala, Inna Voloshina, Mikhail S. Goncharuk, Li Yu, Ya-Ping Zhang, Mariko Sashika, Hang Lee, Mi-Sook Min
    Zoological Science 35 3 249 - 259 2018年06月01日 [査読有り][通常論文]
     
    The raccoon dog (Nyctereutes procyonoides) is endemic to East Asia but has been introduced in Europe. Its high adaptability enabled its rapid colonization of European countries, where population growth has been raising concerns regarding ecosystem disturbance and the spread of zoonotic diseases. The genetic diversity and structure of endemic, source, and introduced populations from seven locations across South Korea, China, Russian Far East, Finland (spread to Finland after introduction to European part of Russia from Russian Far East), Vietnam, and Japan (Honshu and Hokkaido) were examined based on 16 microsatellite loci. Two major and significantly different (FST = 0.236) genetic clusters were found: continental (South Korean, Chinese, Russian, Finnish, and Vietnamese) and island (Japanese) populations. The continental raccoon dog population comprises three subpopulations (Chinese-Russian-Finnish, South Korean, and Vietnamese) and the Japanese population consists of Honshu and Hokkaido subpopulations. The genetic diversity and geographic structure of raccoon dogs in East Asia has been influenced by natural barriers to gene flow and reveals a typical central-marginal trend in genetic diversity (continental vs. island, and central vs. marginal or source vs. introduced within continental populations). The detected differences between continental and island populations agree with those reported in previous studies that considered these populations as different species.
  • Kadariya R, Shimozuru M, Maldonado JE, Moustafa MAM, Sashika M, Tsubota T
    PloS one 13 12 e0207662  2018年 [査読有り][通常論文]
  • Mohamed Abdallah Mohamed Moustafa, Michito Shimozuru, Wessam Mohamed, Kyle Rueben Taylor, Ryo Nakao, Mariko Sashika, Toshio Tsubota
    PARASITOLOGY RESEARCH 116 8 2321 - 2325 2017年08月 [査読有り][通常論文]
     
    Sarcocystis and Hepatozoon species are protozoan parasites that are frequently detected in domestic and wild animals. Rodents are considered common intermediate and paratenic hosts for several Sarcocystis and Hepatozoon species. Here, blood DNA samples from a total of six rodents, including one Myodes rutilus, one Myodes rufocanus, and four Apodemus speciosus, collected from Hokkaido, Japan, were shown by conventional PCR of the 18S ribosomal RNA (rRNA) gene to contain Sarcocystis and Hepatozoon DNA. Sequencing of the DNA detected one Sarcocystis sp. in the M. rufocanus sample and two different Hepatozoon spp. in the M. rutilus and A. speciosus samples. Phylogenetic analysis showed that the detected Sarcocystis sp. sequence grouped with GenBank Sarcocystis sequences from rodents, snakes, and raccoons from Japan and China. The 18S rRNA partial gene sequences of both detected Hepatozoon spp. clustered with GenBank Hepatozoon sequences from snakes, geckos and voles in Europe, Africa, and Asia. This study provides evidence that wild rodents have a role in the maintenance of Sarcocystis and Hepatozoon species on the island of Hokkaido.
  • Elzahara Elbaz, Mohamed Abdallah Mohamed Moustafa, Kyunglee Lee, Wessam Ahmed Mohamed Mohamed, Ryo Nakao, Michito Shimozuru, Mariko Sashika, Emad Elsayed Ahmed Younis, Sabry Ahmed El-Khodery, Toshio Tsubota
    TICKS AND TICK-BORNE DISEASES 8 5 802 - 807 2017年 [査読有り][通常論文]
     
    Babesia and Theileria species are tick-borne protozoan parasites that have a veterinary and zoonotic importance. In order to investigate the prevalence and genetic diversity of these parasites, a total of 269 sika deer blood DNA samples collected from Hokkaido, Japan, were examined for Babesia and Theileria species by touch-down PCR targeting the 18S rRNA gene. Reverse line blot (RLB) hybridization was then used to detect 12 piroplasm species. The results revealed that 95.5% (257/269), 94.1% (253/269), 14.1% (38/269), 87.7% (236/269) and 11.5% (31/269) of the examined PCR products hybridized with the probes which were designed to detect all Babesia and Theileria spp., all Theileria spp., all Babesia spp., Theileria sp. Thrivae and Babesia divergens-like, respectively. The 18S rRNA gene partial sequences were divided into Theileria sp. Thrivae, T. capreoli, B. divergens-like and an undescribed Babesia species. This study showed the first detection of the undescribed Babesia sp. from Japan. Therefore, more studies are required to understand the ecology of the newly detected tick-borne pathogens in Hokkaido.
  • Paudel S, Villanueva MA, Mikota SK, Nakajima C, Gairhe KP, Subedi S, Rayamajhi N, Sashika M, Shimozuru M, Matsuba T, Suzuki Y, Tsubota T
    The Journal of veterinary medical science 78 7 1117 - 1121 2016年07月 [査読有り][通常論文]
     
    We developed an interferon-gamma release assay (IGRA) specific for Asian elephants (Elephas maximus). Whole blood collected from forty captive Asian elephants was stimulated with three different mitogens i.e., phytohemagglutinin (PHA), pokweed mitogen (PWM) and phorbol myristate aceteate/ionomycin (PMA/I). A sandwich ELISA that was able to recognize the recombinant elephant interferon-gamma (rEIFN-gamma) as well as native interferon-gamma from the Asian elephants was performed using anti-elephant IFN-gamma rabbit polyclonal antibodies as capture antibodies and biotinylated anti-elephant IFN-gamma rabbit polyclonal antibodies as detection antibodies. PMA/I was the best mitogen to use as a positive control for an Asian elephant IGRA. The development of an Asian elephant-specific IGRA that detects native IFN-gamma in elephant whole blood provides promising results for its application as a potential diagnostic tool for diseases, such as tuberculosis (TB) in Asian elephants.
  • Mohamed Abdallah Mohamed Moustafa, Kyle Taylor, Ryo Nakao, Michito Shimozuru, Mariko Sashika, Roberto Rosa, May June Thu, Annapaola Rizzoli, Toshio Tsubota
    TICKS AND TICK-BORNE DISEASES 7 5 922 - 928 2016年 [査読有り][通常論文]
     
    Many of the emerging infectious diseases originate in wildlife and many of them are caused by vector borne pathogens. In Japan, zoonotic tick-borne pathogens (TBPs) are frequently detected in both ticks and wildlife. Here, we studied the infection rates of potentially zoonotic species, including Anaplasma, Ehrlichia, Neoehrlichia and Babesia spp., in Hokkaido's most abundant small mammals as they relate to variable extrinsic factors that might affect the infection rates of these pathogens. A total of 412 small mammals including 64 Apodemus argenteus, 219 Apodemus speciosus, 78 Myodes rufocanus, 41 Myodes rutilus, 6 Myodes rex and 4 Sorex unguiculatus were collected from Furano and Shari sites in Hokkaido, Japan, in 2010 and 2011 and were examined by multiplex PCR for TBPs. A reverse line blot hybridization (RLB) was then developed for the specific detection of 13 potentially zoonotic TBPs. A total of 4 TBPs were detected: Anaplasma sp. AP-sd, Ehrlichia muris, Candidatus Neoehrlichia mikurensis and Babesia microti. The infection rates were 4.4% (18/412), 1.2% (5/412), 13.1% (54/412) and 17.2% (71/412), respectively. The infection rates of each of the detected TBPs were significantly correlated with host small mammal species. A total of 22 (two triple and 20 double) co-infection cases were detected (5.3%). The most frequent co-infection cases occurred between Candidatus N. mikurensis and B. microti 68.2% (15/22). Further studies are required to examine human exposure to these zoonotic TBPs in Hokkaido. (C) 2016 Elsevier GmbH. All rights reserved.
  • Mohamed Abdallah Mohamed Moustafa, Kyunglee Lee, Kyle Taylor, Ryo Nakao, Mariko Sashika, Michito Shimozuru, Toshio Tsubota
    INFECTION GENETICS AND EVOLUTION 36 268 - 274 2015年12月 [査読有り][通常論文]
     
    A previously undescribed Anaplasma species (herein referred to as AP-sd) has been detected in sika deer, cattle and ticks in Japan. Despite being highly similar to some strains of A. phagocytophilum, AP-sd has never been detected in humans. Its ambiguous epidemiology and the lack of tools for its specific detection make it difficult to understand and interpret the prevalence of this Anaplasma species. We developed a method for specific detection, and examined AP-sd prevalence in Hokkaido wildlife. Our study included 250 sika deer (Cervus nippon yesoensis), 13 brown bears (Ursus arctos yesoensis) and 252 rodents including 138 (Apodemus speciosus), 45 (Apodemus argenteus), 42 (Myodes rufocanus) and 27 (Myodes rutilus) were collected from Hokkaido island, northern Japan, collected during 2010 to 2015. A 770 bp and 382 bp segment of the 16S rRNA and gltA genes, respectively, were amplified by nested PCR. Results were confirmed by cloning and sequencing of the positive PCR products. A reverse line blot hybridization (RLB) based on the 16S rRNA gene was then developed for the specific detection of AP-sd. The prevalence of AP-sd by nested PCR in sika deer was 51% (128/250). We detected this Anaplasma sp. for the first time in wild brown bears and rodents with a prevalence of 15% (2/13) and 2.4% (6/252), respectively. The sequencing results of the 16S rRNA and gltA gene amplicons were divergent from the selected A. phagocytophilum sequences in GenBank. Using a newly designed AP-sd specific probe for RLB has enabled us to specifically detect this Anaplasma species. Besides sika deer and cattle, wild brown bears and rodents were identified as potential reservoir hosts for AP-sd. This study provided a high throughput molecular method that specifically detects AP-sd, and which can be used to investigate its ecology and its potential as a threat to humans in Japan. (C) 2015 Elsevier B.V. All rights reserved.
  • 平川浩文, 木下豪太, 坂田大輔, 坂田大輔, 村上隆広, 車田利夫, 車田利夫, 浦口宏二, 阿部豪, 阿部豪, 佐鹿万里子
    ほ乳類科学 55 2 155‐166 (J‐STAGE)  2015年 [査読有り][通常論文]
  • Emi Yamaguchi, Mariko Sashika, Kei Fujii, Kohei Kobayashi, Vuong Nghia Bui, Haruko Ogawa, Kunitoshi Imai
    VIRUS RESEARCH 189 8 - 13 2014年08月 [査読有り][通常論文]
     
    Raccoons (Procyon lotor), which are not native to Japan, have been suspected to transmit various pathogens by frequent intrusion into agricultural and residential areas. To determine influenza A virus seropositivity in raccoons in Japan, we examined a total of 634 raccoons captured in 19 towns (A-S) from 2009 to 2012. Agar gel precipitation tests showed that the antibody prevalence was 1.89% (12/634). All positive raccoons were captured in three towns (A-C) located within a radius of approximately 30 km, and 75% had antibodies to multiple subtypes (H1, H3-5, N1, N6, and N8). H3 and N8 antibodies were most frequently detected (75%). Among all the raccoons captured, 67% (8/12) were found in town A in 2009 and 2010, and all five raccoons captured in 2010 had H3 and N8 antibodies, suggesting that transmission of the subtype might occur. H5 and N1 antibodies were also detected in two raccoons captured in town A. Virus neutralization tests examining the highly pathogenic avian influenza virus (HPAIV) H5N1 subtype (four isolates of which have been detected in Japan to date) and the low PAIV (LPAIV) H5N3 subtype showed that raccoon sera highly cross-reacted with three H5N1 strains (clade 2.5: Ck/Yamaguchi/7/04; clade 2.3.2.1: Whooper swan/Hokkaido/1/08 and Whooper swan/Hamanaka/11), while they displayed a low cross-reactivity with the antisera to the clade 2.2 virus (Ck/Miyazaki/K11/07) and H5N3 LPAIV (Whistling swan/Shimane/499/83). Thus, the origin of the H5N1 virus was not clearly defined. The viral M gene was detected in four antibody-negative raccoons captured in three towns by real-time reverse transcription-polymerase chain reaction (rRT-PCR) with high Ct values, although no virus was isolated. This study is the first report showing that raccoons of Japan were infected with multiple subtypes of influenza A virus, including H5N1. It remains to be elucidated how raccoons play a role in persistence of influenza A virus in nature and if they could pose risks to animal and human health, for example, by playing a role as "mixing vessel" to generate novel strains of influenza A virus. (C) 2014 Elsevier B.V. All rights reserved.
  • Adrian Patalinghug Ybanez, Mariko Sashika, Hisashi Inokuma
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76 2 307 - 312 2014年02月 [査読有り][通常論文]
     
    The present study aimed to determine the complete citrate synthase (gltA) and heat-shock protein (groEL) gene sequences of Anaplasma bovis and to infer phylogenetic relationships within the genus Anaplasma. Multiple alignments from single and concatenated sequences of the 16S rRNA, gltA and groEL genes of the genus Anaplasma were subjected to phylogenetic analyses. Percent identities of A. bovis nucleotide sequences were found highest with A. phagocytophilum in gltA (65.4%) and groEL (79.8%). Single gene phylogenetic tree results assumed similar phylogenetic positions within the genus Anaplasma, except for A. bovis. However, consensus and concatenated sequence phylogenetic trees showed similar results, revealing 2 subgroups within the genus.
  • Kyunglee Lee, Ai Takano, Kyle Taylor, Mariko Sashika, Michito Shimozuru, Satoru Konnai, Hiroki Kawabata, Toshio Tsubota
    TICKS AND TICK-BORNE DISEASES 5 6 841 - 847 2014年 [査読有り][通常論文]
     
    A relapsing fever Borrelia sp. similar to Borrelia lonestari (herein referred to as B. lonestari-like) was detected from wild sika deer (Cervus nippon yesoensis) and Haemaphysalis ticks in the eastern part of Hokkaido, Japan. The total prevalence of this Borrelia sp. in tested deer blood samples was 10.6% using conventional PCR and real-time PCR. The prevalence was significantly higher in deer fawns compared to adults (21.9% and 9.4%, respectively). Additionally, there was significant regional difference between our two sampling areas, Shiretoko and Shibetsu with 17% and 2.8% prevalence, respectively. Regional differences were also found in tick species collected from field and on deer. In the Shiretoko region, Haemaphysalis spp. were more abundant than Ixodes spp., while in Shibetsu, Ixodes spp. were more abundant. Using real-time PCR analysis, B. lonestari-like was detected from 2 out of 290 adult Haemaphysalis spp. ticks and 4 out of 76 pools of nymphs. This is the first report of a B. lonestari-like organism in Haemaphysalis spp. ticks, and the first phylogenetic analysis of this B. lonestari-like organism in Asia. Based on our results, Haemaphysalis spp. are the most likely candidates to act as a vector for B. lonestari-like; furthermore, regional variation of B. lonestari-like prevalence in sika deer may be dependent on the population distribution of these ticks. (C) 2014 Elsevier GmbH. All rights reserved.
  • Minami W. Okuyama, Michito Shimozuru, Go Abe, Mariko Nakai, Mariko Sashika, Ken-Ichiro Shimada, Nobuhiro Takahashi, Daisuke Fukui, Ryohei Nakamura, Toshio Tsubota
    JOURNAL OF REPRODUCTION AND DEVELOPMENT 59 4 361 - 367 2013年08月 [査読有り][通常論文]
     
    The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.
  • 藤井啓, 佐鹿万里子, 小林恒平, 今井邦俊, 山口英美
    北海道獣医師会雑誌 56 8 440  2012年08月10日 [査読有り][通常論文]
  • 藤井啓, 尾上貞雄, 佐鹿万里子, 小林恒平, 今井邦俊, 山口英美, 仙名和浩
    日本獣医師会雑誌 65 2 118 - 121 2012年02月20日 [査読有り][通常論文]
  • Mariko Sashika, Go Abe, Kotaro Matsumoto, Hisashi Inokuma
    VECTOR-BORNE AND ZOONOTIC DISEASES 11 4 349 - 354 2011年04月 [査読有り][通常論文]
     
    Infection by Anaplasma and Ehrlichia in feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined by molecular methods. A polymerase chain reaction (PCR) screen for Anaplasmataceae, based on 16S rRNA, showed that 38 (5.4%) of 699 raccoons examined were positive. These 38 positive samples were examined for Anaplasma phagocytophilum, Anaplasma bovis, Ehrlichia chaffeensis, and Ehrlichia canis infection by species-specific nested PCR. Nested PCR results indicated that 36 of the 38 samples were positive for A. bovis. All 38 samples were PCR negative for A. phagocytophilum, E. chaffeensis, and E. canis. This is the first report of the detection of A. bovis in the peripheral blood of raccoons. A total of 124 raccoons were infested with ticks, including Ixodes ovatus, Ixodes persulcatus, and Haemaphysalis spp. The rate of A. bovis infection in raccoons infested with Haemaphysalis spp. (46.7%, 7/15) was significantly higher than that in raccoons without Haemaphysalis spp. infestation (3.7%, 4/109, p< 0.001). No significant differences were observed in A. bovis infection rates between raccoons infested with I. ovatus or I. persulcatus and those not so infested. A total of four ticks (two males and two nymphs) and one larval pools from four raccoons showed positive for A. bovis-specific nested PCR. This results support the correlation between the A. bovis infection of raccoons and Haemaphysalis infestation. In conclusion, raccoons could be possible reservoir animals for A. bovis, and A. bovis infection in raccoons may be related to infestation with Haemaphysalis spp.
  • Taisuke Horimoto, Ken Maeda, Shin Murakami, Maki Kiso, Kiyoko Iwatsuki-Horimoto, Mariko Sashika, Toshihiro Ito, Kazuo Suzuki, Mayumi Yokoyama, Yoshihiro Kawaoka
    Emerging infectious diseases 17 4 714 - 7 2011年04月 [査読有り][通常論文]
     
    Although raccoons (Procyon lotor) are susceptible to influenza viruses, highly pathogenic avian influenza virus (H5N1) infection in these animals has not been reported. We performed a serosurvey of apparently healthy feral raccoons in Japan and found specific antibodies to subtype H5N1 viruses. Feral raccoons may pose a risk to farms and public health.
  • 阿部豪, 三好英勝, 佐鹿万里子, 中井真理子, 島田健一郎, 上田一徳, 富樫崇, 池田透, 立澤史郎, 室山泰之
    ほ乳類科学 51 2 257-263 (J-STAGE)  2011年 [査読有り][通常論文]
  • 阿部豪, 平川浩文, 増田隆一, 佐鹿万里子, 中井真理子, 島田健一郎
    ほ乳類科学 51 2 321-325 (J-STAGE)  2011年 [査読有り][通常論文]
  • Mariko Sashika, Go Abe, Kotaro Matsumoto, Hisashi Inokuma
    JAPANESE JOURNAL OF INFECTIOUS DISEASES 63 5 353 - 354 2010年09月 [査読有り][通常論文]
     
    Rickettsial infection in feral raccoons (Procyon lotor) in Hokkaido, Japan was analyzed by molecular methods. Genus-specific nested polymerase chain reaction (PCR) analysis based on the Rickettsia citrate synthase (gltA) gene showed that 13 of 699 raccoons (1.9%) examined were positive for Rickettsia. Twelve of the 13 partial gltA sequence amplicons were successfully analyzed. The nucleotide sequence of one amplicon was identical to both Rickettsia heilongjiangensis and R. japonica, one was identical to R. felis, and the rest to R. helvetica. This is the first report on the detection of rickettsial agents in peripheral blood of raccoons.
  • 佐鹿 万里子, 森田 達志, 的場 洋平, 岡本 実, 谷山 弘行, 猪熊 壽, 浅川 満彦
    日本野生動物医学会誌 14 2 125 - 128 日本野生動物医学会 2009年09月 [査読有り][通常論文]
     
    2005年2月、北海道北広島市にて腰部から尾部にかけ著しい脱毛と痂皮を形成したアライグマProcyon lotor雄幼獣一個体が捕獲され、当該病変部から多数の小型ダニ類が検出された。形態および2nd internal transcribed spacer(ITS-2)の塩基配列から、これらのダニ類はSarcoptes scabieiと同定された。本症例は日本産アライグマのS.scabieiによる疥癬の初報告となった。(著者抄録)
  • Yoshito Ohno, Hiroshi Sato, Kazuo Suzuki, Mayumi Yokoyama, Shigehiko Uni, Takahiro Shibasaki, Mariko Sashika, Hisashi Inokuma, Kazushige Kai, Ken Maeda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 71 8 1035 - 1039 2009年08月 [査読有り][通常論文]
     
    Japanese encephalitis virus (JEV) infects numerous animal species including humans, horses and pigs. In this study, antibodies against JEV ill feral raccoons (Procyon lotor), wild boars (Sus scrofa) and raccoon dogs (Nyctereutes procyonoides) in Japan were examined. The results showed that 40.7% (22 out of 54), 64.5% (40 Out of 62), 69.1% (47 out of 68) and 0% (0 out of 20) of raccoons in Hyogo, Osaka, Wakayama and Hokkaido, respectively, had virus-neutralizing antibodies against JEV. In addition, 83.3% (30 out of 36) or wild boars and 63.2% (12 out of 19) of raccoon dogs in Wakayama were seropositive for JEV. There were no significant differences in seroprevalence of JEV between males and females or between adults and juveniles in these wild animals. JEV seroprevalence was compared between 37 raccoons and 30 wild boars captured in a limited period (November 2007 to February 2008), and we found that wild boars (86.7%) were significantly more seropositive for JEV antibody than raccoons (59.5%). In conclusion, JEV was prevalent ill wild mammals, indicating that the possibility of JEV infection in humans may still be high in Japan. In addition, these wild animals may be good sentinels to estimate JEV infection risk in residents, as they live near humans and are not vaccinated.
  • 阿部豪, 青柳正英, 的場洋平, 佐鹿万里子, 車田利夫, 高野恭子, 池田透, 立澤史郎
    ほ乳類科学 93 169 - 175 2006年12月30日 [査読有り][通常論文]
  • 本邦の動物園展示用クマ類から検出されたクマカイチュウ Baylisascaris transfuga (回虫科: 線形動物門)の体部計測値に関する検討
    浅川満彦, 佐鹿万里子, 村田浩一
    酪農学園大学紀要 30 1 99-101  2005年 [査読有り][通常論文]

講演・口頭発表等

その他活動・業績

共同研究・競争的資金等の研究課題

  • 外来種アライグマの影響を抑制するには?-アライグマ管理戦略と在来種の保全を目指して-
    公益財団法人 日本生命財団:
    研究期間 : 2018年10月 -2019年09月 
    代表者 : 佐鹿 万里子
  • 外来種アライグマと在来種タヌキの競合関係解明に関する研究
    タカラハーモニストファンド:
    研究期間 : 2016年06月 -2017年05月 
    代表者 : 佐鹿 万里子
  • 北海道のエゾタヌキにおける疥癬およびジステンパーの疫学研究
    公益財団法人秋山記念生命科学振興財団:
    研究期間 : 2011年04月 -2012年03月 
    代表者 : 佐鹿 万里子

教育活動情報

主要な担当授業

  • 獣医科学基礎科目A 野生動物/保全医学特論
    開講年度 : 2020年
    課程区分 : 博士後期課程
    開講学部 : 獣医学研究科
  • 大学院共通授業科目(一般科目):自然科学・応用科学
    開講年度 : 2020年
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : wildlife medicine, conservation medicine, infectious disease, zoonosis, endangered species
  • 野生動物学演習
    開講年度 : 2020年
    課程区分 : 学士課程
    開講学部 : 獣医学部
  • 環境獣医科学特論
    開講年度 : 2020年
    課程区分 : 博士後期課程
    開講学部 : 獣医学院
  • アドバンスト演習
    開講年度 : 2020年
    課程区分 : 学士課程
    開講学部 : 獣医学部
  • 野生動物/保全医学特論
    開講年度 : 2020年
    課程区分 : 博士後期課程
    開講学部 : 獣医学院
  • 野生動物学演習
    開講年度 : 2020年
    課程区分 : 学士課程
    開講学部 : 獣医学部
    キーワード : 保全生態学、野生動物医学、保全医学、生態系、保護管理


Copyright © MEDIA FUSION Co.,Ltd. All rights reserved.