論文 - 岡林 環樹
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Nosocomial Severe Fever with Thrombocytopenia Syndrome in Companion Animals, Japan, 2022 査読あり
Mekata H., Umeki K., Yamada K., Umekita K., Okabayashi T.
Emerging Infectious Diseases 29 ( 3 ) 614 - 617 2023年3月
担当区分：責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Emerging Infectious Diseases
In Japan, 2 cats that underwent surgery in a room where a sick dog had been euthanized became ill within 9 days of surgery. Severe fever with thrombocytopenia syndrome virus was detected in all 3 animals; nucleotide sequence identity was 100%. Suspected cause was an uncleaned pulse oximeter probe used for all patients.
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Editorial: Zoonotic diseases among pigs 査読あり
Lin C.N., Okabayashi T., Tummaruk P., Ooi P.T.
Frontiers in Veterinary Science 9 2023年1月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Frontiers in Veterinary Science
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宮崎ワンヘルス研究会の取り組み 招待あり
岡林 環樹
日本獣医師会雑誌 2022年9月
担当区分：筆頭著者, 責任著者 記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Retrospective study on the possibility of an SFTS outbreak associated with undiagnosed febrile illness in veterinary professionals and a family with sick dogs in 2003. 査読あり
Kirino Y, Yamanaka Y, Ishijima K, Tatemae K, Maeda K, Okabayashi T.
Journal of Infection and Chemotherapy 2022年3月
担当区分：責任著者 掲載種別：研究論文（学術雑誌）
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Rapid inactivation of Dabie bandavirus (SFTSV) by irradiation with deep-ultraviolet light-emitting diode. 査読あり
Kaneko C, Saito A, Inagaki H, Sugiyama H, Mazimpaka E, Fujimoto S, Okabayashi T.
Journal of Medical Virology 2022年3月
担当区分：責任著者 掲載種別：研究論文（学術雑誌）
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Serological and molecular survey of tick borne pathogens, severe fever with thrombocytopenia syndrome (SFTS) virus, spotted fever group rickettsiae, and Orientia tsutsugamushi, in wild boars (Sus scrofa) in Miyazaki prefecture, Japan. 査読あり
Kirino Y, Yamamoto S, Nomachi Ngan MY, Sato Y, Sudaryatma PE, Junzo Norimine J, Fujii Y, Ando S, Okabayashi T.
Veterinary Medicine and Science 2022年3月
担当区分：責任著者 掲載種別：研究論文（学術雑誌）
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Seroprevalence of severe fever with thrombocytopenia syndrome virus in small-animal veterinarians and nurses in the Japanese prefecture with the highest case load. 査読あり
Kirino Y, Ishijima K, Miura M, Nomachi T, Mazimpaka E, Sudaryatma PE, Yamanaka A, Maeda K, Sugimoto T, Saito A, Mekata H, Okabayashi T.
Viruses 2021年2月
担当区分：責任著者 掲載種別：研究論文（学術雑誌）
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Direct TaqMan assay for the detection and genotyping of bovine viral diarrhea virus types 1 and 2
Ullah S., Notsu K., Saito A., Okabayashi T., Mekata H., Isoda N., Sekiguchi S.
Archives of Virology 170 ( 1 ) 15 2025年1月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Archives of Virology
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.
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Indonesian Herb Extracts Inhibit the Replication of Bovine Respiratory Syncytial Virus: In Vitro Study 査読あり 国際共著
Bambang Pontjo Priosoeryanto1,3 , Putu Eka Sudaryatma5,6 , Nafrina Lanniari1 , Surachmi Setiyaningsih2 , Eva Harlina1, Retno Wulansari1, Rachmi Ridho4, Riski Rostantinata1, Putu Angga Wiradana8, Tamaki Okabayashi5,6,7*
HAYATI Journal of Biosciences 32 ( 3 ) 2025年
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
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Mekata H., Yamada K., Umeki K., Yamamoto M., Ochi A., Umekita K., Kobayashi I., Hirai T., Okabayashi T.
BMC Veterinary Research 20 ( 1 ) 190 2024年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：BMC Veterinary Research
Severe fever with thrombocytopenia syndrome (SFTS) is a fatal zoonosis caused by ticks in East Asia. As SFTS virus (SFTSV) is maintained between wildlife and ticks, seroepidemiological studies in wildlife are important to understand the behavior of SFTSV in the environment. Miyazaki Prefecture, Japan, is an SFTS-endemic area, and approximately 100 feral horses, called Misaki horses (Equus caballus), inhabit Cape Toi in Miyazaki Prefecture. While these animals are managed in a wild-like manner, their ages are ascertainable due to individual identification. In the present study, we conducted a seroepidemiological survey of SFTSV in Misaki horses between 2015 and 2023. This study aimed to understand SFTSV infection in horses and its transmission to wildlife. A total of 707 samples from 180 feral horses were used to determine the seroprevalence of SFTSV using enzyme-linked immunosorbent assay (ELISA). Neutralization testing was performed on 118 samples. In addition, SFTS viral RNA was detected in ticks from Cape Toi and feral horses. The overall seroprevalence between 2015 and 2023 was 78.5% (555/707). The lowest seroprevalence was 55% (44/80) in 2016 and the highest was 92% (76/83) in 2018. Seroprevalence was significantly affected by age, with 11% (8/71) in those less than one year of age and 96.7% (435/450) in those four years of age and older (p < 0.0001). The concordance between ELISA and neutralization test results was 88.9% (105/118). SFTS viral RNA was not detected in ticks (n = 516) or feral horses. This study demonstrated that horses can be infected with SFTSV and that age is a significant factor in seroprevalence in wildlife. This study provides insights into SFTSV infection not only in horses but also in wildlife in SFTS-endemic areas.
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Complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021
Mekata H., Yamamoto M., Matsui Y., Niazi A.M., Yamada K., Okabayashi T., Cha S.Y., Jang H.K.
Microbiology Resource Announcements 13 ( 9 ) e0006024 2024年9月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Microbiology Resource Announcements
Here, we report the complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021, which was determined using the Illumina MiSeq platform. The position of the hemagglutinin-neuraminidase stop codon differed from that of the only other available completely sequenced prototype strain, duck/New York/22/1977.
DOI： 10.1128/mra.00060-24
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Conserved Antagonization of Type I Interferon Signaling by Arterivirus GP5 Proteins
Ringo R.S., Choonnasard A., Okabayashi T., Saito A.
Viruses 16 ( 8 ) 2024年8月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Viruses
Arteriviruses can establish persistent infections in animals such as equids, pigs, nonhuman primates, rodents, and possums. Some Arteriviruses can even cause overt and severe diseases such as Equine Arteritis in horses and Porcine Reproductive and Respiratory Syndrome in pigs, leading to huge economic losses. Arteriviruses have evolved viral proteins to antagonize the host cell’s innate immune responses by inhibiting type I interferon (IFN) signaling, assisting viral evasion and persistent infection. So far, the role of the Arterivirus glycoprotein 5 (GP5) protein in IFN signaling inhibition remains unclear. Here, we investigated the inhibitory activity of 47 Arterivirus GP5 proteins derived from various hosts. We demonstrated that all GP5 proteins showed conserved activity for antagonizing TIR-domain-containing adapter proteins inducing interferon-β (TRIF)-mediated IFN-β signaling through TRIF degradation. In addition, Arterivirus GP5 proteins showed a conserved inhibitory activity against IFN-β signaling, induced by either pig or human TRIF. Furthermore, certain Arterivirus GP5 proteins could inhibit the induction of IFN-stimulated genes. These findings highlight the role of Arterivirus GP5 proteins in supporting persistent infection.
DOI： 10.3390/v16081240
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Conserved Functions of Orthohepadnavirus X Proteins to Inhibit Type-I Interferon Signaling
Choonnasard A., Shofa M., Okabayashi T., Saito A.
International Journal of Molecular Sciences 25 ( 7 ) 2024年4月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of Molecular Sciences
Orthohepadnavirus causes chronic hepatitis in a broad range of mammals, including primates, cats, woodchucks, and bats. Hepatitis B virus (HBV) X protein inhibits type-I interferon (IFN) signaling, thereby promoting HBV escape from the human innate immune system and establishing persistent infection. However, whether X proteins of Orthohepadnavirus viruses in other species display a similar inhibitory activity remains unknown. Here, we investigated the anti-IFN activity of 17 Orthohepadnavirus X proteins derived from various hosts. We observed conserved activity of Orthohepadnavirus X proteins in inhibiting TIR-domain-containing adaptor protein inducing IFN-β (TRIF)-mediated IFN-β signaling pathway through TRIF degradation. X proteins from domestic cat hepadnavirus (DCH), a novel member of Orthohepadnavirus, inhibited mitochondrial antiviral signaling protein (MAVS)-mediated IFNβ signaling pathway comparable with HBV X. These results indicate that inhibition of IFN signaling is conserved in Orthohepadnavirus X proteins.
DOI： 10.3390/ijms25073753
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Hirohisa Mekata 1 , Ikuo Kobayashi 2 , Tamaki Okabayashi 3
Ticks and Tick-borne Diseases 14 ( 6 ) 102237 2023年11月
担当区分：最終著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Ticks and Tick-borne Diseases
New technologies have led to the discovery of novel tick-borne and tick-associated viruses. Dabieshan tick virus (DaTV) and Okutama tick virus (OkTV), which belong to the family Phenuiviridae, were discovered in ticks in China and Japan, respectively, in the 2010s. Although it is unknown whether these viruses cause disease in animals or humans, all tick-associated viruses have the potential to become etiological agents of infectious diseases through gene reassortment. Therefore, it is important to elucidate the ecology of these viruses, regardless of their pathogenicity. In this study, ticks were collected year-round in Cape Toi, Miyazaki Prefecture, Japan, and an epidemiological survey of tick-associated phenuiviruses was performed. A total of 516 ticks collected from the vegetation by dragging flannel sheets were used for analysis. Pan-phenuivirus reverse transcription PCR was performed on the tick samples, and DaTV and OkTV were detected. We found that 37.0% (85/230) and 23% (16/71) of nymphal and adult Haemaphysalis longicornis were infected with DaTV, respectively, and 10% (6/62) and 13% (1/8) of nymphal and adult Haemaphysalis flava were infected with OkTV, respectively. Phylogenetic analysis indicated that the DaTV identified in this study formed a unique clade that was distinct from the strains identified in China. The survey revealed that DaTV is distributed not only in China, but also in Japan. We believe that this study contributes to our understanding of the prevalence of tick-associated viruses.
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Possible Transmission of Severe Fever with the Thrombocytopenia Syndrome Virus to an Individual Who Buried an Infected Cat 査読あり
Hirohisa Mekata 1 , Takeshi Kawaguchi 2 , Kosho Iwao 2 , Kazumi Umeki 3 , Kentaro Yamada 1 4 , Kunihiko Umekita 2 5 , Tamaki Okabayashi 1 4
Jpn J INfect Dis 2023年5月
担当区分：最終著者 掲載種別：研究論文（学術雑誌）
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Heavy metals content in fresh tuna and swordfish caught from Hindian and Pacific Oceans: Health risk assessment of dietary exposure 査読あり 国際共著
Adnorita Fandah Oktariani 1 , Putu Eka Sudaryatma 2 , Yan Ramona 3 4 , I Made Gelgel Wirasuta 5 , Ida Bagus Gede Darmayasa 4 , Putu Angga Wiradana 6 , Tamaki Okabayashi 7 8
Vet World 2023年4月
担当区分：最終著者 掲載種別：研究論文（学術雑誌）
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Oktariani A.F., Sudaryatma P.E., Ramona Y., Wirasuta I.M.G., Darmayasa I.B.G., Wiradana P.A., Okabayashi T.
Veterinary World 16 ( 4 ) 858 - 868 2023年4月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Veterinary World
Background and Aim: Yellowfin tuna and swordfish are seafood commodities commonly caught from deep oceans worldwide. Therefore, this study aimed to assess the levels of three heavy metals, namely, cadmium (Cd), lead (Pb), and mercury (Hg) in yellowfin tuna and swordfish. The results are expected to provide consumers with information on the safety of consuming or exporting these fishes caught in the Hindian and Pacific Oceans. Materials and Methods: Fresh yellowfin and swordfish were obtained from fishermen’s catches in FAO Fishing Zone 57 (Indian Ocean) and 71 (Pacific Ocean) and then collected at Benoa Harbor, Bali Province. The comparative method was to evaluate the levels of heavy metals in each fish. Furthermore, heavy metal concentrations, including Pb, Cd, and Hg, were determined using atomic absorption spectroscopy analysis. These results were then used to assess the safety of these fishes by calculating the estimated daily intake (EDI) and target hazard quotients-total target hazard quotients (THQs-TTHQs). Results: The analysis showed that none of the samples exceeded the threshold levels for the three heavy metals, which was specified by the Indonesian National Standard (SNI) and European Commission Regulation (CR) No. 1881/2006. The EDI and provisional tolerable weekly index (PTWI) obtained in this study were still in the safe range. However, the PTWI values for Pb in yellowfin tuna product from the Indian Ocean were higher (0.0038 mg/kg) compared to the recommended standard for the adult population. The THQ-TTHQ values of fish caught from these oceans were also within the acceptable range specified by the two agencies, indicating that they are safe for consumption by people with various age groups and for export purposes. Conclusion: The average levels of three heavy metals (Cd, Pb, and Hg) in muscle samples of yellowfin tuna and swordfish caught from the Pacific and Hindian Oceans were within the acceptable range as specified by the SNI and CR No. 1881/2006. Furthermore, the EDI and THQs values indicated that fishes caught from the Pacific and Hindian Oceans were safe for consumption. This research is still limited to assessing two capture fisheries commodities. Further research is needed on the assessment of heavy metal levels in other capture fisheries commodities in this capture zone.
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Kaneko C., Mekata H., Umeki K., Sudaryatma P.E., Irie T., Yamada K., Misawa N., Umekita K., Okabayashi T.
Ticks and Tick-borne Diseases 14 ( 2 ) 102115 2023年3月
担当区分：最終著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Ticks and Tick-borne Diseases
Severe fever with thrombocytopenia syndrome (SFTS) is a fatal emerging tick-borne zoonotic disease caused by the SFTS virus (SFTSV). SFTSV infection in humans and companion animals is a matter of concern in endemic areas. Various wild animals are involved in the transmission cycle of SFTSV with vector ticks. Because the home range of medium-sized wild mammals commonly overlaps with humans’ living spheres, this study aimed to reveal the endemicity of SFTSV in such mammals. This study investigated the prevalence of antibodies against SFTSV and viral RNA in medium-sized wild mammals in Miyazaki Prefecture, Japan where human cases have been most frequently reported in Japan and performed a phylogenetic analysis to compare the detected SFTSV with those previously reported. Forty-three of 63 (68%) Japanese badgers (Meles anakuma) and 12 of 53 (23%) Japanese raccoon dogs (Nyctereutes procyonoides viverrinus) had antibodies against SFTSV. Japanese marten (n = 1), weasels (n = 4), and Japanese red fox (n = 1) were negative. Two of 63 (3%) badgers tested positive for SFTSV RNA, whereas the other species were negative. Phylogenetic analysis of the partial nucleotide sequence of SFTSV revealed that viral RNA detected from badgers exhibited 99.8% to 100% similarity to SFTSV, as previously reported in humans, cat, and ticks in the study area. This study demonstrated high seropositivity of antibodies in medium-sized wild mammals and suggested that SFTSV could be shared among these mammals, humans, and companion animals in endemic areas.
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Jia J., Zhao M., Ma K., Zhang H., Gui L., Sun H., Ren H., Okabayashi T., Zhao J.
Veterinary Sciences 10 ( 3 ) 2023年3月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Veterinary Sciences
OmpH is among the most important virulence factors of Pasteurella multocida, which mediates septicemia in yaks (Bos grunniens I) after infection with the bacteria. In the present study, yaks were infected with wild-type (WT) (P0910) and OmpH-deficient (ΔOmpH) P. multocida strains. The mutant strain was generated through the reverse genetic operation system of pathogens and proteomics technology. The live-cell bacterial count and clinical manifestations of P. multocida infection in Qinghai yak tissues (thymus, lung, spleen, lymph node, liver, kidney, and heart) were analyzed. The expression of differential proteins in the yak spleen under different treatments was analyzed using the marker-free method. We found that compared with the mutant strain, the titer of wild-type strains was significantly higher in tissues. Additionally, compared with other organs, the bacteria titer was significantly higher in the spleen. Compared with the WT p0910 strain, the mutant strain generated milder pathological changes in the tissues of yak. Proteomics analysis revealed that 57 of the 773 proteins expressed in P. multocida were significantly differentially expressed between the ΔOmpH and P0910 groups. Of the 57, 14 were over-expressed, whereas 43 were under-expressed. The differentially expressed proteins in the ΔompH group regulated the ABC transporter (ATP-powered translocation of many substrates across membranes) system, the two-component system, RNA degradation, RNA transcription, glycolysis/gluconeogenesis, biosynthesis of ubiquinone and other terpenoid-quinones, oxidative phosphorylation (citrate cycle) as well as fructose and mannose metabolism. The relationship among 54 significantly regulated proteins was analyzed using STRING. We found that WT P0910 and ΔOmpH of P. multocida infection activated the expression of ropE, HSPBP1, FERH, ATP10A, ABCA13, RRP7A, IL-10, IFN-γ, IL-17A, EGFR, and dnaJ. Overall, deletion of the OmpH gene weakened the virulence but maintained the immunogenicity of P. multocida in yak. The findings of this study provide a strong foundation for the pathogenesis of P. multocida and the management of related septicemia in yaks.
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Development of a direct duplex real-time PCR assay for rapid detection of domestic cat hepadnavirus
Shofa M., Ohkawa A., Okabayashi T., Kaneko Y., Saito A.
Journal of Veterinary Diagnostic Investigation 35 ( 2 ) 139 - 144 2023年3月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Veterinary Diagnostic Investigation
Domestic cat hepadnavirus (DCH) is a novel hepadnavirus, first identified in 2018. DCH is generally detected using conventional PCR assays, which include time-consuming agarose gel electrophoresis. We developed a rapid, sensitive, and specific real-time PCR (rtPCR) assay for the detection of the DCH genome. To streamline the procedure, our rtPCR assay was carried out using blood samples, without DNA extraction. A consensus primers/probe set was designed based on the nucleotide sequences of the surface/polymerase gene of all DCH strains available in GenBank. To exclude the possibility that the PCR reaction was blocked by anticoagulants, we also used a primers/probe set for amplifying the cat beta-actin gene as a reference gene. Our direct duplex rtPCR assay had high sensitivity, with a limit of detection of 10 copies/μL of blood for DCH. Our direct duplex rtPCR assay should be a useful tool for DCH detection and surveillance.