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Affiliation |
Center for Animal Disease Control |
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Title |
Associate Professor |
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Related SDGs |
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MEKATA Hirohisa
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Research Areas 【 display / non-display 】
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Life Science / Veterinary medical science
Papers 【 display / non-display 】
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Development of multiplex reverse-transcription digital PCR assay for co-detection of bovine leukemia virus and bovine viral diarrhea virus in cattle. Reviewed International coauthorship International journal
Shakir Ullah, Kosuke Notsu, Akatsuki Saito, Tamaki Okabayashi, Hirohisa Mekata, Mai Shiokawa, Hiroshi Aoki, Satoshi Sekiguchi
Journal of virological methods 340 115298 - 115298 2026.2
Language：English Publishing type：Research paper (scientific journal)
Bovine leukemia virus (BLV) and bovine viral diarrhea virus (BVDV) are important transboundary pathogens that cause substantial economic losses in the cattle industry globally. Their early detection and control are critical for preventing disease transmission and minimizing their impact on livestock health and productivity. Therefore, establishing a sensitive and robust diagnostic method capable of simultaneously detecting BLV and BVDV is vital for implementing timely control measures. Here, we developed a multiplex RT-dPCR assay to detect BLV and BVDV in a single-tube reaction using nucleic acid extracted from whole blood of infected cattle. The multiplex RT-dPCR assay successfully detected both BLV and BVDV with high specificity, exhibiting no cross-reactivity with other bovine viruses including Akabane virus, bovine coronavirus, bovine parainfluenza virus 3, bovine respiratory syncytial virus, bovine herpesvirus 1, and bovine immunodeficiency virus. The assay demonstrated the ability to detect BVDV-1 and BVDV-2 at minimum titers of 10² and 10 ³ TCID₅₀/mL, respectively. For BLV, the multiplex RT-dPCR assay exhibited a detection limit as low as 18.7 viral copies. Our findings represent a significant advance in the detection of BLV and BVDV from extracted RNA and cDNA, highlighting the potential of assays for achieving improved diagnostic accuracy and early disease intervention.
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Importance of continuous monitoring of bovine leukaemia virus infection on farms in bovine leukaemia virus-endemic areas of Japan. Reviewed International journal
Chikako Tani, Jiazhou Li, Hirohisa Mekata, Kazuhiro Morishita, Shingo Nakahata
Veterinary record open 12 ( 2 ) e70014 2025.12
Language：English Publishing type：Research paper (scientific journal)
BACKGROUND: Enzootic bovine leukosis (EBL), caused by the bovine leukaemia virus (BLV), has exhibited increasing infection rates in Japan. While many farms implement various infection prevention measures, practical challenges-such as barn structure and availability of replacement cattle-can hinder farm purification efforts. This study aimed to determine whether continuous monitoring of BLV proviral load (PVL) in cattle on a farm could be effective in tracking BLV infection dynamics, identification of BLV infection sources and the dynamics of BLV PVL enrichment on-farm. METHODS: Bovine leukaemia virus infection was monitored over a 3-year period in approximately 10% of cattle at a test farm located in Miyazaki Prefecture, an endemic area for BLV in southern Kyushu, Japan. Eight calves and five adult cows were included to assess vertical and horizontal transmission of BLV. RESULTS: All calves developed new BLV infections, which were traced to the nursing/growing barn, the dry/new milking barn at the Miyazaki farm, and the point of deposit in Hokkaido, Japan, for rearing and artificial insemination. In BLV-positive adult cows, an increasing trend in PVL was observed. These findings indicate that continuous monitoring of a subset of cattle enables effective tracking of infection dynamics and identification of infection sources; thus, supporting the implementation of targeted prevention measures. CONCLUSIONS AND CLINICAL IMPORTANCE: Despite heightened awareness among farmers regarding livestock quarantine, consistent and long-term control of BLV infections remains challenging. The results underscore the necessity of expert-guided management strategies tailored to BLV control, informed by ongoing infection monitoring. This study highlights husbandry management factors, including barn structure and cattle boarding practices, and provides new insights into the transmission routes of BLV in Japan.
DOI： 10.1002/vro2.70014
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Development of a Double-Antigen Sandwich ELISA for Oz Virus and a Seroepidemiological Survey in Wild Boars in Miyazaki, Japan. Reviewed International journal
Hirohisa Mekata, Mari Yamamoto, Aya Matsuu, Ken Maeda, Haruhiko Isawa, Kentaro Yoshii, Kazumi Umeki, Tamaki Okabayashi
Pathogens 14 ( 12 ) 1288 - 1288 2025.12
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
Oz virus, an emerging tick-borne thogotovirus, has been reported to cause fatal human infection in Japan. However, its ecology and geographic distribution remain largely unknown. In this study, we developed a double-antigen sandwich enzyme-linked immunosorbent assay (DAgS ELISA) for detecting Oz virus antibodies in animals and used it to conduct a seroepidemiological survey of wild boars (Sus scrofa) in Miyazaki Prefecture, Japan. Recombinant Oz virus nucleoprotein was expressed in E. coli and used as both the capture and detection antigen. Relative to the neutralization test, the DAgS ELISA showed a sensitivity of 72.2%, a specificity of 88.2%, and an overall concordance rate of 79.0%. We used this assay to examine 1045 wild boar serum samples collected between November 2022 and May 2025, finding a seroprevalence of 33.5%. The seroprevalence did not significantly differ by sex, age, or region, but showed significant seasonal variation, peaking in summer (p < 0.0001). Oz virus RNA was detected by quantitative RT-PCR in one serum sample (0.09%). Phylogenetic analysis of the partial Oz virus glycoprotein gene showed that this strain shared 98.8% nucleotide identity with the EH8 strain, which was the first Oz virus isolate obtained from ticks in Ehime Prefecture. These findings suggest that wild boars in Miyazaki are frequently exposed to Oz virus and that ticks in the region harbor the virus. However, no human cases have been reported to date. The DAgS ELISA developed in this study provides a practical tool for serological surveillance in animals. Continuous monitoring of animal populations is warranted to clarify the epidemiology of Oz virus in the region and to identify potential reservoir species.
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Development of a multiplex real-time PCR assay for bovine immunodeficiency virus and bovine leukemia virus and its application to a large-scale survey in Kyushu, Japan. Reviewed International journal
Mari Yamamoto, Tomohiro Okagawa, Satoru Konnai, Hirohisa Mekata
Journal of Veterinary Medical Science 87 ( 10 ) 1164 - 1169 2025.10
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
Bovine immunodeficiency virus (BIV) and bovine leukemia virus (BLV) are retroviruses infecting cattle, with BLV being a known cause of enzootic bovine leukosis. In contrast, BIV is considered non-pathogenic and has been less studied, despite its relevance to animal lentiviral evolution. This study aimed to develop and validate a multiplex real-time PCR assay for simultaneous detection of BIV proviral DNA and quantification of BLV proviral load. Novel primers and probes targeting the BIV pol gene were designed. The assay demonstrated a detection limit of 10 copies per reaction with a probability of 83%, comparable to conventional nested PCR. Importantly, the addition of BIV primers and probes did not interfere with the accurate quantification of BLV. Furthermore, BIV detection was unaffected even in samples with high BLV proviral loads, confirming the assay's robustness for simultaneous detection. The validated assay was applied to a molecular epidemiological survey of 6,051 cattle in the Kyushu region of Japan, conducted between 2021 and 2025. No BIV proviral DNA was detected in any sample, indicating a low prevalence of BIV in this population. This multiplex PCR assay provides a sensitive, efficient, and labor-saving tool for integrated surveillance of retroviral infections in cattle. Furthermore, it offers a valuable platform for future studies on the epidemiology and ecological role of BIV in bovine populations.
DOI： 10.1292/jvms.25-0278
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Urine of Cats with Severe Fever with Thrombocytopenia Syndrome: A Potential Source of Infection Transmission Reviewed International journal
Hirohisa Mekata, Mari Yamamoto, Yasuyuki Kaneko, Kentaro Yamada, Tamaki Okabayashi, Akatsuki Saito
Pathogens 14 ( 3 ) 254 - 254 2025.3
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG
Severe fever with thrombocytopenia syndrome (SFTS), caused by infection with the SFTS virus, is an emerging fatal tick-borne zoonosis endemic to East Asia. Although SFTS is a tick-borne disease, the virus can be transmitted from animals with SFTS without a tick bite. Direct transmission of the SFTS virus from animals to humans has been reported; however, the transmission route is unclear in some cases. Therefore, this study focused on the possibility of SFTS virus transmission through urine and attempted to isolate the infectious virus from the urine of animals with SFTS. Since more efficient cell isolation is needed to determine whether the SFTS virus is present, we first expressed dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), the major receptor for the virus, in Vero cells (Vero-DC-SIGN cells) using a retroviral vector. When inoculated with equal amounts of the SFTS virus strain and SFTS-virus-infected animal serum, Vero-DC-SIGN cells had 42–136% and 20–85% more foci, respectively, than their parent Vero cells. After confirming that Vero-DC-SIGN cells were more suitable for the isolation of the SFTS virus, we investigated whether it could be isolated from the urine of eight cats and two dogs with SFTS. The virus was isolated from 25 μL of urine from two cats with SFTS. Considering that cats excrete 50–100 mL of urine per day, the transmission of the SFTS virus via the urine of cats with SFTS cannot be ruled out. Individuals examining or caring for cats suspected of having SFTS should be aware of the possibility of viral transmission via urine.
Books 【 display / non-display 】
MISC 【 display / non-display 】
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The Development of MALDI-ToF MS-based Analysis for the Direct Detection of SARS-CoV-2 in Nasopharyngeal Swabs
林克彦, 吉成知也, 廣瀬昌平, 大屋賢司, 大西貴弘, 渡辺麻衣子, 田原口智士, 目堅博久, 谷口隆秀, 前田卓哉, 折原悠太, 川村利江子, 新井沙倉, 斎藤嘉朗, 合田幸広, 工藤由起子
日本薬学会年会要旨集(Web) 143rd 2023
Language：Japanese Publishing type：Research paper, summary (national, other academic conference)
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牛伝染性リンパ腫の診断と早期発症予測法の開発
富永みその, 今内覚, 岡川朋弘, 神谷可菜, 齋藤麻矢, 安富一郎, 目堅博久, 前川直也, 村田史郎, 大橋和彦
北海道獣医師会雑誌 67 ( 8 ) 2023
Language：Japanese Publishing type：Research paper, summary (national, other academic conference)
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MALDI-ToF/MSによるSARS-CoV-2の新規検出法の開発
廣瀬昌平, 吉成知也, 林克彦, 大屋賢司, 大西貴弘, 渡辺麻衣子, 田原口智士, 目堅博久, 谷口隆秀, 新井沙倉, 合田幸広, 工藤由起子
日本獣医学会学術集会講演要旨集 165th (CD-ROM) 2022
Language：Japanese Publishing type：Research paper, summary (national, other academic conference)
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次世代シーケンス(NGS)を用いた豚糞便中のウイルス検索:新しいBastrovirus遺伝子の発見
長井誠, 岡林環樹, 松鵜彩, 藤本佳万, 目堅博久, 中尾亮, 浅井鉄夫, 中川敬介, 伊藤壽啓, 野中成晃, 小原恭子, 猪島康雄, 水谷哲也, 三澤尚明
日本獣医学会学術集会講演要旨集 163rd 2020
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Encouragement of bovine leukemia control measure based on bovine leukemia virus proviral load
Hirohisa MEKATA
The Journal of Farm Animal in Infectious Disease 7 ( 4 ) 163 - 168 2018.12
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution)
Presentations 【 display / non-display 】
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オズウイルスの二重抗原ELISA法の開発と流行状況調査
目堅博久
第7回SFTS研究会学術集会 (長崎大学・坂本キャンパス) 2025.10.12
Event date： 2025.10.11 - 2025.10.12
Language：Japanese Presentation type：Oral presentation (general)
Venue：長崎大学・坂本キャンパス Country：Japan
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Studies on emerging tick-borne viral diseases in companion and wild animals in Japan Invited International conference
Hirohisa Mekata
Faculty of Veterinary Medicine - Seminar for NCM Microbiology - Veterinary Infectious Diseases: (Hanoi, Vietnam) 2025.3.18 Faculty of Veterinary Medicine, Vietnam National University of Agriculture
Event date： 2025.3.18
Language：English Presentation type：Public lecture, seminar, tutorial, course, or other speech
Venue：Hanoi, Vietnam Country：Viet Nam
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伴侶動物と野生動物のSFTS
目堅博久
第2回RCGLID&CADIC共同セミナー (大分大学) 2024.12.2 大分大学グローカル感染症研究センター（RCGLID）
Event date： 2024.12.2
Language：Japanese Presentation type：Public lecture, seminar, tutorial, course, or other speech
Venue：大分大学 Country：Japan
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2021-23年度に宮崎⼤学で実施した伴侶動物の SFTS 検査
目堅博久, 金子泰之, 平井卓哉, 梅木一美, 梅北邦彦, 山田健太郎, 岡林環樹
第6回SFTS研究会 (札幌市) 2024.9.14 SFTS研究会
Event date： 2024.9.14 - 2024.9.15
Language：Japanese Presentation type：Oral presentation (general)
Venue：札幌市 Country：Japan
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Urine from cats with severe fever with thrombocytopenia syndrome could be an infectious source International conference
Hirohisa Mekata, Yasuyuki Kaneko, Kentaro Yamada, Tamaki Okabayashi, Akatsuki Saito
The 4th Joint Meeting of Veterinary Science in East Asia (Obihiro) 2024.9.8 The Japanese Society of Veterinary Science
Event date： 2024.9.8 - 2024.9.9
Language：English Presentation type：Oral presentation (general)
Venue：Obihiro Country：Japan
Awards 【 display / non-display 】
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日本獣医学会獣医学奨励賞
2013.3 日本獣医学会
目堅 博久
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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第１５５回日本獣医学会大会長賞
2013.3 日本獣医学会
目堅 博久
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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2024年度宮崎銀行ふるさと振興助成事業 学術研究部門
2025.3 一般財団法人みやぎん経済研究所 伴侶動物におけるSFTSの実態解明
目堅博久
Award type：Award from publisher, newspaper, foundation, etc. Country：Japan
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日本産業動物獣医学会九州地区学会長賞
2014.10 日本産業動物獣医学会
目堅 博久
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
Grant-in-Aid for Scientific Research 【 display / non-display 】
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マダニが保有するＭ分節欠損フェヌイウイルスの生物学的意義の解明
Grant number：25K22364 2025.06 - 2027.03
独立行政法人日本学術振興会 科学研究費基金 挑戦的研究(萌芽)
目堅 博久
Authorship：Principal investigator
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動物フォーミーウイルスベクターの基盤構築と牛伝染性リンパ腫ワクチンの開発
Grant number：23K23765 2024.04 - 2026.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(B)
目堅博久
Authorship：Principal investigator
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ベトナムにおけるアフリカ豚熱の実践的な高感度診断法の開発と環境動態の解明 International coauthorship
Grant number：22KK0097 2022.04 - 2027.03
独立行政法人日本学術振興会 科学研究費基金 国際共同研究加速基金(国際共同研究強化(B))
山崎渉, 目堅博久, 一二三達郎
Authorship：Coinvestigator(s)
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Construction of animal foamy virus vector and development of enzootic bovine leukosis vaccine
Grant number：22H02500 2022.04 - 2026.03
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Authorship：Principal investigator
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Studies on anti-tumor potential of symbiotic retroviruses and their therapeutic applications
Grant number：20H03150 2020.04 - 2024.03
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Authorship：Coinvestigator(s)