論文 - 目堅 博久
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Importance of continuous monitoring of bovine leukaemia virus infection on farms in bovine leukaemia virus-endemic areas of Japan. 査読あり 国際誌
Chikako Tani, Jiazhou Li, Hirohisa Mekata, Kazuhiro Morishita, Shingo Nakahata
Veterinary record open 12 ( 2 ) e70014 2025年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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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Hirohisa Mekata, Mari Yamamoto, Yasuyuki Kaneko, Kentaro Yamada, Tamaki Okabayashi, Akatsuki Saito
Pathogens 14 ( 3 ) 254 - 254 2025年3月
担当区分：筆頭著者, 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：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.
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Tomohiro OKAGAWA, Naomi NOJIRI, Hazuka YOSHIDA-FURIHATA, Naganori NAO, Misono TOMINAGA, Junko KOHARA, Satoshi GONDAIRA, Hidetoshi HIGUCHI, Yohei TAKEDA, Haruko OGAWA, Shinji YAMADA, Kenji MURAKAMI, Yasunori SUZUKI, Shinji TAKAI, Masaki MAEZAWA, Hisashi INOKUMA, Kaori SHIMIZU, Yasuo INOSHIMA, Tatsufumi USUI, Michihito TAGAWA, Mari YAMAMOTO, Hirohisa MEKATA, Mana ESAKI, Makoto OZAWA, Takahiro MATSUDAIRA, Naoya MAEKAWA, Shiro MURATA, Kazuhiko OHASHI, Masumichi SAITO, Satoru KONNAI
Journal of Veterinary Medical Science 87 ( 5 ) 551 - 558 2025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：Japanese Society of Veterinary Science
Bovine leukemia virus (BLV), a retrovirus that is widespread worldwide, causes enzootic bovine leukosis (EBL), a B-cell leukemia/lymphoma with a poor prognosis that ultimately results in death. In Japan, the number of cattle infected with this virus is increasing, and it is estimated more than 35% of cattle are currently infected. Since no vaccines or treatments against BLV infection are currently available, it is important to establish a method of early diagnosis for EBL to reduce economic losses caused by the disposal of EBL cattle in Japan, where a large number of expensive beef cattle are raised. We previously developed Rapid Amplification of the Integration Site without Interference by Genomic DNA Contamination (RAISING), a cost-effective, rapid, and sensitive method for the clonality analysis of BLV-infected cells. Despite its usefulness for the early diagnosis of EBL, RAISING had drawbacks preventing its practical application. Here, we report the development of an improved method, RAISING ver.2, and its performance. Compared to BLV clonality analysis using the previous method, RAISING ver.2 was found to maintain high accuracy and reproducibility despite its simplification. Moreover, its performance was also validated in a multicenter validation study. Taken together, our results strongly suggest that RAISING ver.2 can be fully utilized in clinical practice. Successful commercialization of a RAISING test kit could overcome the concerns of livestock farmers suffering from EBL, thereby promoting a stable supply of Japanese beef, both domestically and internationally.
DOI： 10.1292/jvms.25-0031
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Direct TaqMan assay for the detection and genotyping of bovine viral diarrhea virus types 1 and 2 査読あり 国際共著 国際誌
Shakir Ullah, Kosuke Notsu, Akatsuki Saito, Tamaki Okabayashi, Hirohisa Mekata, Norikazu Isoda, Satoshi Sekiguchi
Archives of Virology 170 ( 1 ) 1 - 10 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：Springer Science and Business Media LLC
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 10<sup>2</sup> TCID<sub>50</sub>/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.DOI： 10.1007/s00705-024-06207-z
その他リンク： https://link.springer.com/article/10.1007/s00705-024-06207-z/fulltext.html
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MALDI-TOF MS analysis for detection of bovine coronavirus with tryptic peptides from viral proteins. 査読あり 国際誌
Katsuhiko Hayashi, Kenji Ohya, Tomoya Yoshinari, Shouhei Hirose, Souta Shimizu, Yuji Morita, Takahiro Ohnishi, Maiko Watanabe, Satoshi Taharaguchi, Hirohisa Mekata, Takahide Taniguchi, Yukiko Hara-Kudo
Journal of microorganism control 29 ( 4 ) 143 - 151 2024年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
Bovine coronavirus (BCoV）, a significant cattle pathogen causing enteric and respiratory diseases, is primarily detected using reverse transcription-polymerase chain reaction. Our objective was to develop a novel detection method for BCoV by matrix-assisted laser desorption/ionization‒time-of-flight mass spectrometry (MALDI-TOF MS）. Peptide mass fingerprint analysis revealed that nucleocapsid (N）, membrane (M）, and hemagglutinin-esterase (HE) were three main BCoV proteins. Their tryptic peptides were used as target molecules for BCoV detection. When the tryptic digest of 107.0 viral copies was analyzed by MALDI-TOF MS, five peptides with relatively strong peaks were detected. The detection limit was between 105.0 and 106.0 copies per test for BCoV alone. To detect BCoV in the swab eluate, ultrafiltration purification achieved a detection limit between 106.0 and 107.0 copies per test, sufficient to detect BCoV-infected calves. Our findings offer valuable insights for BCoV detection by MALDI-TOF MS.
DOI： 10.4265/jmc.29.4_143
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Complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021. 査読あり 国際共著 国際誌
Hirohisa Mekata, Mari Yamamoto, Yuto Matsui, Ahmad Massoud Niazi, Kentaro Yamada, Tamaki Okabayashi, Se-Yeoun Cha, Hyung-Kwan Jang
Microbiology resource announcements 13 ( 11 ) e0006024 2024年11月
担当区分：筆頭著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
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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Nine-year seroepidemiological study of severe fever with thrombocytopenia syndrome virus infection in feral horses in Cape Toi, Japan. 査読あり 国際誌
Hirohisa Mekata, Kentaro Yamada, Kazumi Umeki, Mari Yamamoto, Akihiro Ochi, Kunihiko Umekita, Ikuo Kobayashi, Takuya Hirai, Tamaki Okabayashi
BMC veterinary research 20 ( 1 ) 190 - 190 2024年5月
担当区分：筆頭著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
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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Yuri L Tanaka, Maya Shofa, Erika P Butlertanaka, Ahmad Massoud Niazi, Takuya Hirai, Hirohisa Mekata, Akatsuki Saito
Pathogens 13 ( 1 ) 18 - 18 2023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：MDPI AG
Pigs are important animals for meat production but can carry several zoonotic diseases, including the Japanese encephalitis virus, Nipah virus, and influenza viruses. Several Orthomyxoviridae and Coronavirinae respiratory viruses require cleavage of envelope proteins to acquire viral infectivity and consequently, need a host protease or the addition of exogenous trypsin for efficient propagation. Host TMPRSS2 is a key protease responsible for viral cleavage. Stable expression of human TMPRSS2 in African green monkey-derived Vero cells can enhance the porcine epidemic diarrhea virus. However, considering the narrow host tropism of viruses, a porcine cell line expressing pig TMPRSS2 could be optimal for replicating pig-derived viruses. Herein, we generated and evaluated a pig-derived PK-15 cell line stably expressing pig TMPRSS2. This cell line markedly (>1000-fold) and specifically enhanced the growth of influenza viruses. Furthermore, we demonstrated the usefulness of a PK-15 cell line lacking the Stat2 gene with a stable expression of pig TMPRSS2 for efficient virus isolation from clinical samples in the presence of type I interferons. Therefore, PK-15 cells expressing pig TMPRSS2 could be a valuable and promising tool for virus isolation, vaccine production, and virological studies of TMPRSS2-dependent viruses.
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Genetic and antigenic analyses of H5N8 and H5N1 subtypes high pathogenicity avian influenza viruses isolated from wild birds and poultry farms in Japan in the winter of 2021-2022. 査読あり 国際誌
Kosuke Soda, Hirohisa Mekata, Tatsufumi Usui, Hiroshi Ito, Yuto Matsui, Kentaro Yamada, Tsuyoshi Yamaguchi, Toshihiro Ito
The Journal of veterinary medical science 85 ( 11 ) 1180 - 1189 2023年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
In the winter of 2021-2022, multiple subtypes (H5N8 and H5N1) of high pathogenicity avian influenza viruses (HPAIVs) were confirmed to be circulating simultaneously in Japan. Here, we phylogenetically and antigenically analyzed HPAIVs that were isolated from infected wild birds, an epidemiological investigation of affected poultry farms, and our own active surveillance study. H5 subtype hemagglutinin (HA) genes of 32 representative HPAIV isolates were classified into clade 2.3.4.4b lineage and subsequently divided into three groups (G2a, G2b, and G2d). All H5N8 HPAIVs were isolated in early winter and had HA genes belonging to the G2a group. H5N1 HPAIVs belong to the G2b and G2d groups. Although G2b viruses were widespread throughout the season, G2d viruses endemically circulated in Northeast Japan after January 2022. Deep sequence analysis showed that the four HPAIVs isolated at the beginning of winter had both N8 and N1 subtypes of neuraminidase genes. Environmental water-derived G2a HPAIV, A/water/Tottori/NK1201-2/2021 (H5N8), has unique polymerase basic protein 1 and nucleoprotein genes, similar to those of low pathogenicity avian influenza viruses (LPAIVs). These results indicate that multiple H5 HPAIVs and LPAIVs disseminated to Japan via transboundary winter migration of wild birds, and HPAIVs with novel gene constellations could emerge in these populations. Cross-neutralization test revealed that G2a H5N8 HPAIVs were antigenically distinct from a G2b H5N1 HPAIV, suggesting that antibody pressure in wild birds was involved in the transition of the HPAIV groups during the season.
DOI： 10.1292/jvms.23-0121
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Detection and phylogenetic analysis of Dabieshan tick virus and Okutama tick virus in ticks collected from Cape Toi, Japan. 査読あり 国際誌
Hirohisa Mekata, Ikuo Kobayashi, Tamaki Okabayashi
Ticks and tick-borne diseases 14 ( 6 ) 102237 - 102237 2023年8月
担当区分：筆頭著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
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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Nosocomial Severe Fever with Thrombocytopenia Syndrome in Companion Animals, Japan, 2022 査読あり 国際誌
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：筆頭著者 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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Seroprevalence of severe fever with thrombocytopenia syndrome virus in medium-sized wild mammals in Miyazaki, Japan 査読あり 国際共著 国際誌
Chiho Kaneko, Hirohisa Mekata, Kazumi Umeki, Putu Eka Sudaryatma, Takao Irie, Kentaro Yamada, Naoaki Misawa, Kunihiko Umekita, Tamaki Okabayashi
Ticks and Tick-borne Diseases 14 ( 2 ) 102115 - 102115 2023年3月
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Possible transmission of severe fever with thrombocytopenia syndrome virus (SFTSV) to a person who buried the corpus of a dead cat, which died of SFTSV infection. 査読あり 国際誌
Hirohisa Mekata, Takeshi Kawaguchi, Kosho Iwao, Kazumi Umeki, Kentaro Yamada, Kunihiko Umekita, Tamaki Okabayashi
Japanese journal of infectious diseases 76 ( 3 ) 211 - 214 2023年1月
担当区分：筆頭著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a causative agent of SFTS. Although SFTS is a fatal tick-borne zoonosis, the virus can infect humans without tick bite exposure. Recently, direct SFTSV transmission from companion pets to humans has become a significant problem. Herein, we reported a case of SFTSV transmission from a dead community cat to a woman who buried the cat in Miyazaki prefecture, Japan. The community cat died without a diagnosis of SFTS, and the woman buried it without precaution. Nine days later, the woman developed symptoms of SFTS. SFTS viral RNA and anti-SFTSV antibodies were detected in the woman. The animal carcass was exhumed, and tissue samples were collected to confirm viral infection in the cat. High copy numbers of viral RNA were detected. Sequences of the SFTSV M segment in samples from the cat and the woman showed 100% homology. The woman stated that she had touched blood that had leaked from the body when she buried it. On the other hand, the woman could have been infected when she took the cat to the animal hospital. This study highlights the risk of SFTSV infection via contact with sick or dead community cats.
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Generation of a bovine cell line for gene engineering using an HIV-1-based lentiviral vector. 査読あり 国際誌
Nanami Morizako, Erika P Butlertanaka, Yuri L Tanaka, Honoka Shibata, Tamaki Okabayashi, Hirohisa Mekata, Akatsuki Saito
Scientific reports 12 ( 1 ) 16952 - 16952 2022年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
Human immunodeficiency virus type 1 (HIV-1)-based lentiviral vectors are indispensable tools for gene engineering in mammalian cells. Conversely, lentiviral vector transduction is severely inhibited in bovine cells. Previous studies demonstrated that this inhibition is caused by the anti-lentiviral host factor tripartite motif containing 5 (TRIM5), which targets incoming HIV-1 virions by interacting with the viral capsid. In this study, we investigated several methods for overcoming the limited applicability of lentiviral vectors in bovine cells. First, we demonstrated that the SPRY domain of bovine TRIM5 is the major determinant of anti-viral activity. Second, we found that mutations that allow the capsid to evade rhesus macaque TRIM5α minimally rescued HIV-1 infectivity in bovine-derived MDBK cells. Third, we found that cyclosporine A, which relieves the inhibition of HIV-1 infection in monkey cells, significantly rescued the impaired HIV-1 infectivity in MDBK cells. Lastly, we successfully generated a bovine cell line lacking intact TRIM5 using the CRISPR/Cas9 technique. This TRIM5 knockout cell line displayed significantly higher susceptibility to an HIV-1-based lentiviral vector. In conclusion, our findings provide a promising gene engineering strategy for bovine cells, thereby contributing to innovations in agriculture and improvements in animal health.
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黒毛和種牛における牛伝染性リンパ腫ウイルスの垂直感染の発生状況とリスク要因 査読あり
楠田 絵梨子, 浅野 康子, 米重 隆一, 目堅 博久
家畜診療 69 ( 9 ) 527 - 532 2022年9月
担当区分：最終著者 記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：全国農業共済協会
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Survival of SARS-CoV-2 and bovine coronavirus on common surfaces of living environments. 査読あり 国際誌
Maiko Watanabe, Takahiro Ohnishi, Sakura Arai, Tsuyoshi Kawakami, Katsuhiko Hayashi, Kenji Ohya, Shouhei Hirose, Tomoya Yoshinari, Satoshi Taharaguchi, Hirohisa Mekata, Takahide Taniguchi, Yoshiaki Ikarashi, Masamitsu Honma, Yukihiro Goda, Yukiko Hara-Kudo
Scientific reports 12 ( 1 ) 10624 - 10624 2022年6月
記述言語：英語 掲載種別：研究論文（学術雑誌）
Aerosols or saliva containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can contaminate living environments, and viruses can be indirectly transmitted. To understand the survival potential of the virus, the viral titers of bovine coronavirus (BCoV), as a model virus, and SARS-CoV-2 were measured on porous and non-porous surfaces. The amount of infectious BCoV recovered remained relatively high on non-porous substrates. However, it quickly decreased on several non-porous surfaces such as nitrile rubber. The time taken to reach the limit of detection on non-woven masks, as a porous substrate, was longer than that of non-porous substrates. On porous substrates other than non-woven masks, the amount of virus recovered quickly decreased, and then remained at a low level. Representative substrates were tested with SARS-CoV-2. The decrease in the amount of infectious virus recovered was similar to that of BCoV, although that of SARS-CoV-2 was more rapid. RNA derived from SARS-CoV-2 was also detected using real-time PCR, and it remained on surfaces much longer than infectious virus, on all substrates. Therefore, it is important to measure the viral titer to avoid the overestimation of infectious virus contamination in the environments. Our results suggest that the surface structure was not directly related to viral survivability.
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Single-Nucleotide Polymorphism on Spermatogenesis Associated 16 Gene-Coding Region Affecting Bovine Leukemia Virus Proviral Load. 査読あり 国際誌
Hirohisa Mekata, Mari Yamamoto
Veterinary sciences 9 ( 6 ) 2022年6月
担当区分：筆頭著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
Bovine leukemia virus (BLV) is an etiological agent of malignant lymphoma in cattle and is endemic in many cattle-breeding countries. Thus, the development of cattle genetically resistant to BLV is desirable. The purpose of this study was to identify novel single-nucleotide polymorphisms (SNPs) related to resistance to BLV. A total of 146 DNA samples from cattle with high BLV proviral loads (PVLs) and 142 samples from cattle with low PVLs were used for a genome-wide association study (GWAS). For the verification of the GWAS results, an additional 1342 and 456 DNA samples from BLV-infected Japanese Black and Holstein cattle, respectively, were used for an SNP genotyping PCR to compare the genotypes for the identified SNPs and PVLs. An SNP located on the spermatogenesis associated 16 (SPATA16)-coding region on bovine chromosome 1 was found to exceed the moderate threshold (p < 1.0 × 10-5) in the Additive and Dominant models of the GWAS. The SNP genotyping PCR revealed that the median values of the PVL were 1278 copies/50 ng of genomic DNA for the major homozygous, 843 for the heterozygous, and 621 for the minor homozygous genotypes in the Japanese Black cattle (p < 0.0001). A similar tendency was also observed in the Holstein cattle. We found that cattle with the minor allele for this SNP showed 20-25% lower PVLs. Although the mechanisms through which this SNP impacts the PVL remain unknown, we found a novel SNP related to BLV resistance located on the SPATA16 gene-coding region on bovine chromosome 1.
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Matrix-Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry Analysis for the Direct Detection of SARS-CoV-2 in Nasopharyngeal Swabs. 査読あり 国際誌
Tomoya Yoshinari, Katsuhiko Hayashi, Shouhei Hirose, Kenji Ohya, Takahiro Ohnishi, Maiko Watanabe, Satoshi Taharaguchi, Hirohisa Mekata, Takahide Taniguchi, Takuya Maeda, Yuta Orihara, Rieko Kawamura, Sakura Arai, Yoshiro Saito, Yukihiro Goda, Yukiko Hara-Kudo
Analytical chemistry 94 ( 10 ) 4218 - 4226 2022年3月
記述言語：英語 掲載種別：研究論文（学術雑誌）
The most common diagnostic method used for coronavirus disease-2019 (COVID-19) is real-time reverse transcription polymerase chain reaction (PCR). However, it requires complex and labor-intensive procedures and involves excessive positive results derived from viral debris. We developed a method for the direct detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal swabs, which uses matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-ToF MS) to identify specific peptides from the SARS-CoV-2 nucleocapsid phosphoprotein (NP). SARS-CoV-2 viral particles were separated from biological molecules in nasopharyngeal swabs by an ultrafiltration cartridge. Further purification was performed by an anion exchange resin, and purified NP was digested into peptides using trypsin. The peptides from SARS-CoV-2 that were inoculated into nasopharyngeal swabs were detected by MALDI-ToF MS, and the limit of detection was 106.7 viral copies. This value equates to 107.9 viral copies per swab and is approximately equivalent to the viral load of contagious patients. Seven NP-derived peptides were selected as the target molecules for the detection of SARS-CoV-2 in clinical specimens. The method detected between two and seven NP-derived peptides in 19 nasopharyngeal swab specimens from contagious COVID-19 patients. These peptides were not detected in four specimens in which SARS-CoV-2 RNA was not detected by PCR. Mutated NP-derived peptides were found in some specimens, and their patterns of amino acid replacement were estimated by accurate mass. Our results provide evidence that the developed MALDI-ToF MS-based method in a combination of straightforward purification steps and a rapid detection step directly detect SARS-CoV-2-specific peptides in nasopharyngeal swabs and can be a reliable high-throughput diagnostic method for COVID-19.
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ダイレクトPCR法による牛伝染性リンパ腫感染源リスク牛の検出 査読あり
宮本 真智子, 川内 京子, 榊原 伸一, 宮根 和弘, 目堅 博久
日本獣医師会雑誌 75 ( 3 ) e46 - e50 2022年3月
担当区分：最終著者 記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Hirohisa Mekata, Eriko Kusuda, Chiho Mori
Veterinary Sciences 8 ( 11 ) 255 - 255 2021年10月
担当区分：筆頭著者, 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：MDPI AG
Although natural suckling from dams with bovine leukemia virus (BLV) has not been recommended in Japan, the frequency of BLV transmission through natural suckling under natural conditions is still unclear. The purpose of this study was to elucidate the risk of BLV transmission through natural suckling. Dams with BLV were classified into three groups (high, middle, low) based on the proviral loads (PVLs). PCR positivity of their colostrum and the correlations between the ratios of calves with BLV and types of feeding milk were analyzed. In dams with low PVLs, no colostrum or calves were confirmed to have BLV. In dams with middle and high PVLs, 17 out of 25 (68.0%) colostrum were PCR positive, and 10 out of 23 (43.4%) and 13 out of 29 (44.8%) calves with natural suckling and artificial rearing were infected with BLV, respectively. No difference was confirmed between the infection rates of natural-suckled and artificially reared calves. Thus, we concluded that the avoidance of natural suckling from dams with BLV and the introduction of artificial rearing were low priority countermeasures against BLV transmission.
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Yukiko Sato, Hirohisa Mekata, Putu Eka Sudaryatma, Yumi Kirino, Seigo Yamamoto, Shuji Ando, Takayuki Sugimoto, Tamaki Okabayashi
Vector-Borne and Zoonotic Diseases 21 ( 5 ) 378 - 384 2021年5月
担当区分：筆頭著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Mary Ann Liebert Inc
Severe fever with thrombocytopenia syndrome (SFTS), caused by Dabie bandavirus, generally called SFTS virus (SFTSV), is an emerging zoonosis in East Asia. In Japan, 50-100 cases of SFTS have been reported each year since the first case was reported in 2013. SFTS is a tick-borne infectious disease, and SFTSV has been isolated from ticks in China and South Korea. Haemaphysalis longicornis and Amblyomma testudinarium are considered the primary vectors in Japan. However, the other tick species seldom feeding on humans might also play an important role in maintaining the virus in nature. In this study, we collected ticks on vegetation around the location where two SFTS patients were estimated to have been infected in Miyazaki Prefecture, Japan, isolated live SFTSV, and performed a phylogenetic analysis. A total of 257 ticks were collected, and SFTSV RNA was detected in 19.5% (9/46) of tick pools. A total of 10 infectious SFTSVs were successfully isolated from A. testudinarium, Haemaphysalis flava, Haemaphysalis formosensis, Haemaphysalis hystricis, and Haemaphysalis megaspinosa. Furthermore, the whole viral sequences isolated from ticks were highly homologous to sequences isolated from SFTS patients in the same sampling area in the past. These results suggest that SFTSVs are maintained in these tick species in the sampling area and sporadically transmitted to humans. Surveillance of SFTSV in ticks provides important information about the risk of incidental transmission to humans.
その他リンク： https://www.liebertpub.com/doi/pdf/10.1089/vbz.2020.2720
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Molecular Epidemiology and Whole-Genome Analysis of Bovine Foamy Virus in Japan 査読あり 国際誌
Hirohisa Mekata, Tomohiro Okagawa, Satoru Konnai, Takayuki Miyazawa
Viruses 13 ( 6 ) 1017 - 1017 2021年5月
担当区分：筆頭著者, 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：MDPI AG
Bovine foamy virus (BFV) is a member of the foamy virus family in cattle. Information on the epidemiology, transmission routes, and whole-genome sequences of BFV is still limited. To understand the characteristics of BFV, this study included a molecular survey in Japan and the determination of the whole-genome sequences of 30 BFV isolates. A total of 30 (3.4%, 30/884) cattle were infected with BFV according to PCR analysis. Cattle less than 48 months old were scarcely infected with this virus, and older animals had a significantly higher rate of infection. To reveal the possibility of vertical transmission, we additionally surveyed 77 pairs of dams and 3-month-old calves in a farm already confirmed to have BFV. We confirmed that one of the calves born from a dam with BFV was infected. Phylogenetic analyses revealed that a novel genotype was spread in Japan. In conclusion, the prevalence of BFV in Japan is relatively low and three genotypes, including a novel genotype, are spread in Japan.
DOI： 10.3390/v13061017
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Yuki Fukushima, Tomoya Minamino, Yoko Mikurino, Kazuyuki Honkawa, Yoichiro Horii, Takako Taniguchi, Hirohisa Mekata, Yosuke Sasaki
Pathogens 10 ( 6 ) 650 - 650 2021年5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：MDPI AG
The objective of the present study was to investigate the effects of Theileria orientalis on the severity of anemia, the prevalence of disease within 21 days after calving and productivity in cows raised inside barns. This longitudinal observational study, which was conducted on a commercial dairy farm in Japan, involved 627 Holstein cows subjected to PCR analysis for T. orientalis. In study 1, we collected blood samples from 156 sick cows within 21 days after calving, and we found the prevalence of T. orientalis infection to be 65.4%. In study 2, we randomly selected 471 cows during the dry period and collected blood samples to conduct PCR analysis for T. orientalis and determined the prevalence of T. orientalis infection to be 69.0%. Compared with the values for the T. orientalis-uninfected group, the T. orientalis-infected cows had significantly decreased hemoglobin concentrations and hematocrit, but there were no differences in the other complete blood count indexes between the two groups. In addition, there were no differences in productivity and the prevalence of major diseases between the T. orientalis-infected and uninfected cows. In summary, T. orientalis had few effects on anemia, productivity and the health of cows raised inside a barn.
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Bovine respiratory coronavirus enhances bacterial adherence by upregulating expression of cellular receptors on bovine respiratory epithelial cells. 査読あり 国際誌
Watcharapong Fahkrajang, Putu Eka Sudaryatma, Hirohisa Mekata, Saori Hamabe, Akatsuki Saito, Tamaki Okabayashi
Veterinary microbiology 255 109017 - 109017 2021年4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）
Bovine coronavirus (BCoV) is one of the agents causing bovine respiratory disease complex (BRDC), with single infection tending to be mild to moderate; the probability of developing pneumonia in BRDC may be affected by viral and bacterial combinations. Previously, we reported that bovine respiratory syncytial virus (BRSV) infection enhances adherence of Pasteurella multocida (PM) to cells derived from the bovine lower respiratory tract but that BRSV infection in cells derived from the upper respiratory tract reduces PM adherence. In this study, we sought to clarify whether the modulation of bacterial adherence to cells derived from the bovine upper and lower respiratory tract is shared by other BRDC-related viruses by infecting bovine epithelial cells from the trachea, bronchus and lung with BCoV and/or PM. The results showed that cells derived from both the upper and lower respiratory tract were susceptible to BCoV infection. Furthermore, all cells infected with BCoV exhibited increased PM adherence via upregulation of two major bacterial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and platelet-activating factor receptor (PAF-R), suggesting that compared with BRSV infection, BCoV infection differentially modulates bacterial adherence. In summary, we identified distinct interaction between bovine respiratory viruses and bacterial infections.
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Chiho KANEKO, Yasuyuki KANEKO, Putu Eka SUDARYATMA, Hirohisa MEKATA, Yumi KIRINO, Ryoji YAMAGUCHI, Tamaki OKABAYASHI
Journal of Veterinary Medical Science 83 ( 4 ) 680 - 684 2021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：Japanese Society of Veterinary Science
We isolated two pseudorabies virus (PRV) isolates (designated OT-1 and OT-2) from two hunting dogs exhibiting neurological manifestations after eating the flesh of wild boar hunted in Oita prefecture, Kyushu Island, Japan. The isolates corresponded to a previously reported PRV (MY-1 strain) isolated from a hunting dog in neighboring Miyazaki prefecture, and it clustered into genotype II based on the glycoprotein C sequence. Our results suggest that this common PRV strain may have been maintained in wild boars on Kyushu Island even though domestic pigs in this area have attained an Aujeszky's disease-free status.
DOI： 10.1292/jvms.20-0450
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Metagenomic identification, sequencing, and genome analysis of porcine hepe-astroviruses (bastroviruses) in porcine feces in Japan. 査読あり 国際誌
Makoto Nagai, Tamaki Okabayashi, Masataka Akagami, Aya Matsuu, Yoshikazu Fujimoto, Md Abul Hashem, Hirohisa Mekata, Ryo Nakao, Keita Matsuno, Yukie Katayama, Mami Oba, Tsutomu Omatsu, Tetsuo Asai, Keisuke Nakagawa, Hiroshi Ito, Hiroo Madarame, Kazuhiro Kawai, Toshihiro Ito, Nariaki Nonaka, Kyoko Tsukiyama-Kohara, Yasuo Inoshima, Tetsuya Mizutani, Naoaki Misawa
Infection, genetics and evolution 88 104664 - 104664 2021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：Elsevier BV
Recently, hepe-astrovirus-like RNA viruses named bastroviruses (BastVs), have been found in human, pig, bat, and rat fecal samples. In this study, we determined nearly complete genome sequences of four BastVs in the feces of healthy pigs. Genetic characterization revealed that these porcine BastVs (PBastVs) and BastVs from other animals including humans, had the same genome organization, that is, they contained three predicted conserved domains of viral methyltransferase, RNA helicase, and RdRp in the nonstructural ORF1 and the astrovirus capsid domain in the structural ORF2. Phylogenetic analyses using RNA-dependent RNA polymerase and the capsid region revealed that PBastVs branched with bat and rat BastVs; however, the groups formed by each host were distantly related to human BastVs. Pairwise amino acid sequence comparison demonstrated that PBastVs shared 95.2-98.6% and 76.1-95.5% sequence identity among each other in the ORF1 and ORF2 regions, respectively; the sequence identities between PBastVs and BastVs from other animals were 21.4-42.5% and 9.1-20.6% in the ORF1 and ORF2 regions, respectively. This suggested that BastVs were derived from a common ancestor but evolved independently in each host population during a prolonged period. Putative recombination events were identified in the PBastV genome, suggesting that PBastVs gain sequence diversity and flexibility through recombination events. In an analysis of previously obtained metagenomic data, PBastV sequence reads were detected in 7.3% (23/315) of fecal samples from pigs indicating that PBastVs are distributed among pig populations in Japan.
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Yumi Kirino, Keita Ishijima, Miho Miura, Taro Nomachi, Eugene Mazimpaka, Putu Eka Sudaryatma, Atsushi Yamanaka, Ken Maeda, Takayuki Sugimoto, Akatsuki Saito, Hirohisa Mekata, Tamaki Okabayashi
Viruses 13 ( 2 ) 229 - 229 2021年2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：MDPI AG
Severe fever with thrombocytopenia syndrome virus (SFTSV) is the causative agent of SFTS, an emerging tick-borne disease in East Asia, and is maintained in enzootic cycles involving ticks and a range of wild animal hosts. Direct transmission of SFTSV from cats and dogs to humans has been identified in Japan, suggesting that veterinarians and veterinary nurses involved in small-animal practice are at occupational risk of SFTSV infection. To characterize this risk, we performed a sero-epidemiological survey in small-animal-practice workers and healthy blood donors in Miyazaki prefecture, which is the prefecture with the highest per capita number of recorded cases of SFTS in Japan. Three small-animal-practice workers were identified as seropositive by ELISA, but one had a negative neutralization-test result and so was finally determined to be seronegative, giving a seropositive rate of 2.2% (2 of 90), which was significantly higher than that in healthy blood donors (0%, 0 of 1000; p < 0.05). The seroprevalence identified here in small-animal-practice workers was slightly higher than that previously reported in other high-risk workers engaged in agriculture and forestry in Japan. Thus, enhancement of small-animal-practice workers’ awareness of biosafety at animal hospitals is necessary for control of SFTSV.
DOI： 10.3390/v13020229
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Yasuko Yamazaki, Uraiwan Thongchankaew-Seo, Konomu Nagao, Hirohisa Mekata, Wataru Yamazaki
Letters in applied microbiology 71 ( 6 ) 560 - 566 2020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：Wiley
Along with progress in globalization of society, the spread of infectious diseases has accelerated worldwide. The deployment of highly sensitive genetic tests is essential for early diagnosis and early containment of potential outbreaks and epidemics, as well as routine surveillance, however tedious and expensive nucleic acid extraction steps represent a major drawback. Here we developed a simple and rapid DNA extraction method, named as an EZ-Fast kit, applicable to the field setting. The kit does not require advanced laboratory equipment or expensive DNA extraction kits and achieves crude DNA extraction within 10 min at extremely low cost and can easily be performed in field settings. When combined with real-time PCR and LAMP analyses, the performance of the POCT, using 183 bovine blood samples, was similar to that of the existing DNA extraction method: 92.5% (135/146) (real-time PCR) and 93.7% (133/142) (LAMP) diagnostic sensitivities, and 100% diagnostic specificities. The developed POCT provides a powerful tool to facilitate on-site diagnosis in a field setting.
DOI： 10.1111/lam.13376
その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/lam.13376
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Direct Transmission of Severe Fever with Thrombocytopenia Syndrome Virus from Domestic Cat to Veterinary Personnel. 査読あり 国際誌
Atsushi Yamanaka, Yumi Kirino, Sho Fujimoto, Naoyasu Ueda, Daisuke Himeji, Miho Miura, Putu E Sudaryatma, Yukiko Sato, Hidenori Tanaka, Hirohisa Mekata, Tamaki Okabayashi
Emerging infectious diseases 26 ( 12 ) 2994 - 2998 2020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：Centers for Disease Control and Prevention (CDC)
Two veterinary personnel in Japan were infected with severe fever with thrombocytopenia syndrome virus (SFTSV) while handling a sick cat. Whole-genome sequences of SFTSV isolated from the personnel and the cat were 100% identical. These results identified a nosocomial outbreak of SFTSV infection in an animal hospital without a tick as a vector.
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Putu Eka Sudaryatma, Akatsuki Saito, Hirohisa Mekata, Meiko Kubo, Watcharapong Fahkrajang, Eugene Mazimpaka, Tamaki Okabayashi
Frontiers in microbiology 11 1676 - 1676 2020年7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 Media SA
Coinfection by bovine respiratory syncytial virus (BRSV) and Pasteurella multocida (PM) frequently has been observed in cattle that develop severe pneumonia. We recently reported that BRSV infection significantly increased PM adherence to bovine lower respiratory tract epithelial cells. However, the molecular mechanisms of enhanced PM adherence are not completely understood. To investigate whether BRSV infection regulates any cellular adherence receptors on bovine bronchus- and lung-epithelial cells, we performed proteomic and functional analyses. The proteomic analysis showed that BRSV infection increased the accumulation of the platelet-activating factor receptor (PAFR) in both cell types. Molecular experiments, including specific blockade, knockdown, and overexpression of PAFR, indicated that PM adherence to these cell types depended on PAFR expression. These findings highlight the role, in cattle with severe pneumonia, of the synergistic effect of coinfection by BRSV and PM in the lower respiratory tract.
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Bovine Respiratory Syncytial Virus Decreased Pasteurella multocida Adherence by Downregulating the Expression of Intercellular Adhesion Molecule-1 on the Surface of Upper Respiratory Epithelial Cells. 査読あり 国際誌
Putu Eka Sudaryatma, Akatsuki Saito, Hirohisa Mekata, Meiko Kubo, Watcharapong Fahkrajang, Tamaki Okabayashi
Veterinary microbiology 246 108748 - 108748 2020年7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：Elsevier BV
The synergistic infection of bovine respiratory syncytial virus (BRSV) and Pasteurella multocida (PM) may predispose cattle to develop severe pneumonia. Previously, we reported that BRSV infection significantly decreased PM adherence to the upper respiratory epithelial cells. It may allow bacteria to invade into the lower respiratory tract and lead to severe pneumonia. To investigate whether BRSV infection regulates the cell surface adherence receptor on bovine trachea epithelial cells (bTECs), we performed proteomic and functional analyses. BRSV infection decreased the expression of intercellular adhesion molecule-1 (ICAM1) on bTECs. Inhibition and knockdown experiments using anti-ICAM1 antibody and siRNAs targeting ICAM1 indicated that PM adherence to bTECs was dependent on ICAM1 expression. These data suggest that under normal conditions bTECs may capture PM in the upper respiratory tract, while BRSV infection reverses this mechanism. The proposed gateway function of bTECs is disrupted by BRSV infection that may facilitate bacterial invasion into the lower respiratory tract and lead to secondary or more severe respiratory infection.
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Ryohei Makino, Yasuko Yamazaki, Konomu Nagao, Francis Victor Apego, Hirohisa Mekata, Wataru Yamazaki
Food and environmental virology 12 ( 2 ) 167 - 173 2020年6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：Springer Science and Business Media LLC
Highly sensitive detection of pathogens is effective for screening meat during quarantine inspection and export. The "micro-amount of virion enrichment technique" (MiVET) was recently developed, which is a new method combining virus concentration with immunomagnetic beads and simple RNA extraction with sodium dodecyl benzenesulfonate (SDBS) for the specific and sensitive detection of avian influenza viruses (AIVs). AIV subtypes H3N2 and H4N2 were used to spike the surface of chicken breast meat samples. The modified MiVET protocol was tested by comparing it against three different homogenate preparation conditions, as well as in samples with added α-amylase and collagenase to digest inhibitors. The performance of the modified MiVET was evaluated by real-time RT-PCR assay targeting the matrix gene. Compared with conventional RNA extraction, the modified MiVET reproducibly concentrated AIVs in chicken meat samples with 100-1000-fold improvement by 60 s-hand homogenization. The 30 s- and 60 s-stomacher homogenizations resulted 100-fold and 10-100-fold improvement, respectively. The modified MiVET required < 60 min from homogenate preparation to final RNA elution. Further, use of the modified MiVET also decreased the rate of false-negative results. The modified MiVET is effective for the rapid and highly sensitive detection of AIVs in chicken meat samples, and can be applied to quarantine and export inspection at airports and seaports.
DOI： 10.1007/s12560-020-09425-1
その他リンク： http://link.springer.com/article/10.1007/s12560-020-09425-1/fulltext.html
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Hirohisa Mekata, Saori Hamabe, Putu Eka Sudaryatma, Ikuo Kobayashi, Toru Kanno, Tamaki Okabayashi
Journal of Veterinary Medical Science 82 ( 6 ) 726 - 730 2020年6月
担当区分：筆頭著者, 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：Japanese Society of Veterinary Science
Bovine coronavirus (BCoV) is an etiological agent of bovine respiratory disease (BRD). BRD is a costly illness worldwide; thus, epidemiological surveys of BCoV are important. Here, we conducted a molecular epidemiological survey of BCoV in respiratory-diseased and healthy cattle in Japan from 2016 to 2018. We found that 21.2% (58/273) of the respiratory-diseased cattle were infected with BCoV. The respiratory-diseased cattle had virus amounts 4.7 times higher than those in the asymptomatic cattle. Phylogenetic analyses showed that the BCoV identified in Japan after 2005 formed an individual lineage that was distinct from the strains found in other countries. These results suggest that BCoV is epidemic and has evolved uniquely in Japan.
DOI： 10.1292/jvms.19-0587
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Slaughterhouse survey for detection of bovine viral diarrhea infection among beef cattle in Kyushu, Japan. 査読あり 国際誌
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
Journal of Veterinary Medical Science 81 ( 10 ) 1450 - 1454 2019年10月
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Co-infection of epithelial cells established from the upper and lower bovine respiratory tract with bovine respiratory syncytial virus and bacteria. 査読あり 国際誌
Sudaryatma PE, Mekata H, Kubo M, Subangkit M, Goto Y, Okabayashi T
Veterinary microbiology 235 80 - 85 2019年8月
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Development of a fluorescent loop-mediated isothermal amplification assay for rapid and simple diagnosis of bovine leukemia virus infection. 査読あり 国際誌
Nagao K, Makino R, Apego FV, Mekata H, Yamazaki W
Journal of Veterinary Medical Science 81 ( 5 ) 787 - 792 2019年5月
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Evaluation of the natural vertical transmission of Theileria orientalis. 査読あり 国際誌
Mekata H, Minamino T, Mikurino Y, Yamamoto M, Yoshida A, Nonaka N, Horii Y
Veterinary parasitology 263 1 - 4 2018年11月
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New Micro-amount of Virion Enrichment Technique (MiVET) to Detect Influenza A Virus in the Duck Feces. 査読あり 国際誌
Yamazaki W, Makino R, Nagao K, Mekata H, Tsukamoto K
Transboundary and emerging diseases 66 ( 1 ) 341 - 348 2018年9月
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Cattle with a low bovine leukemia virus proviral load are rarely an infectious source 査読あり 国際誌
Mekata H, Yamamoto M, Hayashi T, Kirino Y, Sekiguchi S, Konnai S, Horii Y, Norimine J
Japanese Journal of Veterinary Research 66 ( 3 ) 157 - 163 2018年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
その他リンク： https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/71336/1/p157-163%20Hirohisa_Mekata.pdf
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Bovine respiratory syncytial virus infection enhances Pasteurella multocida adherence on respiratory epithelial cells. 査読あり 国際誌
Sudaryatma PE, Nakamura K, Mekata H, Sekiguchi S, Kubo M, Kobayashi I, Subangkit M, Goto Y, Okabayashi T
Veterinary microbiology 220 33 - 38 2018年7月
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Comparison of two agar gel immunodiffusion protocols for diagnosing equine infectious anemia. 査読あり 国際誌
Nemoto M, Yamanaka T, Bannai H, Tsujimura K, Ueno T, Mekata H, Yoshida A, Koyama A, Kokado H
Journal of Veterinary Medical Science 80 ( 8 ) 1245 - 1247 2018年6月
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Molecular epidemiological survey and phylogenetic analysis of bovine influenza D virus in Japan. 査読あり 国際誌
Mekata, H., Yamamoto, M., Hamabe, S., Tanaka, H., Omatsu, T., Mizutani, T., Hause, B.M., Okabayashi, T.
Transboundary and emerging diseases 65 ( 2 ) e355 - e360 2018年4月
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New hematological key for bovine leukemia virus-infected Japanese Black cattle. 査読あり 国際誌
Mekata H, Yamamoto M, Kirino Y, Sekiguchi S, Konnai S, Horii Y, Norimine J
Journal of Veterinary Medical Science 80 ( 2 ) 316 - 319 2018年2月
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Dembo-PCR technique for the detection of bovine abortion, diarrhea, and respiratory disease complex infectious agents in potential vectors and reservoirs. 査読あり 国際誌
Rahpaya, SS, Tsuchiaka S, Kishimoto M, Oba M, Katayama Y, Nunomura Y, Kokawa S, Kimura T, Kobayashi A, Kirino Y, Okabayashi T, Nonaka N, Mekata H, Aoki H, Shiokawa M, Umetsu M, Morita T, Hasebe A, Otsu K, Asai T, Yamaguchi T, Makino S, Murata Y, Abi AJ, Omatsu T, Mizutani T
Journal of veterinary science 2017年12月
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Detection and molecular characterization of equine infectious anemia virus in Mongolian horses. 査読あり 国際誌
Sharav, T., Konnai, S., Ochirkhuu, N., Ts, E.O., Mekata, H., Sakoda, Y., Umemura, T., Murata, S., Chultemdorj, T., Ohashi, K.
Journal of Veterinary Medical Science 79 ( 11 ) 1884 - 1888 2017年11月
記述言語：英語 掲載種別：研究論文（学術雑誌）
The genetic characterization and actual prevalence of EIAV in Mongolian horse in the disease endemic region is currently unknown. Here, 11 of 776 horse serum samples from four Mongolian provinces tested positive on agar gel immunodiffusion test. Genomic DNA extracted from all seropositive samples was subjected to nested PCR assay. Among these, three samples tested positive with nested PCR assay and were identified by sequencing analysis based on long termination repeat and tat gene of the virus. Two of the three sequences were identical, with 94.0% identity with the third. These two independent Mongolian EIAV sequences were retained functional motifs, with no dramatic changes but some variability in the U5 region; they were clustered with genotypes from European countries but not with those from China, U.S.A., or Japan.
DOI： 10.1292/jvms.17-0202
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Intrauterine infection with bovine leukemia virus in pregnant dam with high viral load. 査読あり 国際誌
Sajiki, Y., Konnai, S., Nishimori, A., Okagawa, T., Maekawa, N., Goto, S., Nagano, M., Kohara, J., Kitano, N., Takahashi, T., Tajima, M., Mekata, H., Horn, Y., Murata, S., Ohashi, K.
Journal of Veterinary Medical Science 79 ( 12 ) 2036 - 2039 2017年11月
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Hayashi, T., Mekata, H., Sekiguchi, S., Kirino, Y., Mitoma, S., Honkawa, K., Horii, Y., Norimine, J.
Journal of Veterinary Medical Science 12 ( 79 ) 1552 - 1555 2017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：公益社団法人 日本獣医学会
The bovine MHC (BoLA) class II <i>DRB3</i> alleles are associated with polyclonal expansion of lymphocytes caused by bovine leukemia virus (BLV) infection in cattle. To examine whether the <i>DRB3*0902</i> allele, one of the resistance-associated alleles, is associated with the proviral load, we measured BLV proviral load of BLV-infected cattle and clarified their <i>DRB3</i> alleles. Fifty-seven animals with <i>DRB3*0902</i> were identified out of 835 BLV-infected cattle and had significantly lower proviral load (<i>P</i><0.000001) compared with the rest of the infected animals, in both Japanese Black and Holstein cattle. This result strongly indicates that the BoLA class II DRA/DRB3*0902 molecule plays an important immunological role in suppressing viral replication, resulting in resistance to the disease progression.
DOI： 10.1292/jvms.16-0601
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Phylogenetic analysis of env gene of bovine leukemia virus strains spread in Miyazaki prefecture, Japan 査読あり 国際誌
Marawan, M.A., Mekata, H., Hayashi, T., Sekiguchi, S., Kirino, Y., Horii, Y., Moustafa, A.M., Arnaout, F.K., Galila, E.S.M., Norimine, J.
Journal of Veterinary Medical Science 79 ( 5 ) 912 - 916 2017年5月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.1292/jvms.17-0055
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Sabine, I., Uemura, R., Kirino, Y., Mekata, H., Sekiguchi, S., Farid, A., Goto, Y., Horii, Y., Yamazaki, W.
Food Control 74 107 - 111 2017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：Food Control
© 2016 Elsevier Ltd In a two-year survey of the 24 Japanese broiler chicken flocks at 9 farms from 2013 to 2014, C. jejuni/C. coli prevalence was assessed in a total of 131 slaughtered broiler chicken cecal samples by conventional culture methods and loop-mediated isothermal amplification (LAMP) assay. While 93 samples were C. jejuni/C. coli-negative, 38 (29.0%) showed Campylobacter loads of between 6.4 and 9.0 log CFU/g of ceca in conventional culture methods. The performance of LAMP assay was 100% accurate in terms of diagnostic sensitivity (38/38), specificity (93/93). Furthermore, LAMP assay enabled direct screening of C. jejuni and C. coli in cecal samples from broiler chicken chickens as rapid and cost-effective detection within 90 min and less than 1 US dollar, which can help monitor release of Campylobacter-contaminated chicken into the food chain, thereby reducing the incidence and public health risk of campylobacteriosis. Seasonal changes in C. jejuni and C. coli prevalence in broiler chicken ceca were significantly correlated with the frequency of food poisoning incidents caused by these bacteria in Japan.
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Sabike, I., Uemura, R., Kirino, Y., Mekata, H., Sekiguchi, S., Okabayashi, T., Goto, Y., Yamazaki, W.
Frontiers in Microbiology 7 ( SEP ) 1582 2016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：Frontiers in Microbiology
© 2016 Sabike, Uemura, Kirino, Mekata, Sekiguchi, Okabayashi, Goto and Yamazaki. Rapid identification of Campylobacter-positive flocks before slaughter, following freezing and heat treatment for the Campylobacter-positive carcasses at the slaughterhouses is an effective control strategy against foodborne campylobacteriosis. We evaluated a loop-mediated isothermal amplification (LAMP) assay for the direct screening of naturally contaminated chicken cloacal swabs for C. jejuni/C. coli to compare this assay with conventional qu antitative culture methods. In a comparison study of 165 broilers, the LAMP assay showed 82.8% (48/58 by conventional culture) sensitivity, 100% (107/107) specificity, 100% (48/48) positive predictive value (PPV), and 91.5% (107/117) negative predictive value (NPV). In a comparison of 55 flocks, LAMP showed 90.5% (19/21) sensitivity, 100% (34/34) specificity, 100% (19/19) PPV, and 94.4% (34/36) NPV. In the cumulative total of 28 farm-level comparisons, LAMP showed 100% (12/12) sensitivity, 100% (16/16) specificity, 100% (12/12) PPV, and 100% (16/16) NPV. The LAMP assay required less than 90 min from the arrival of the fecal samples to final results in the laboratory. This suggests that the LAMP assay will facilitate the identification of C. jejuni/C. coli-positive broiler flocks at the farm level or in slaughterhouses before slaughtering, which would make it an effective tool in preventing the spread of Campylobacter contamination.
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Nationwide distribution of bovine influenza D virus infection in Japan 査読あり 国際誌
Horimoto, T., Hiono, T., Mekata, H., Odagiri, T., Lei, Z., Kobayashi, T., Norimine, J., Inoshima, Y., Hikono, H., Murakami, K., Sato, R., Murakami, H., Sakaguchi, M., Ishii, K., Ando, T., Otomaru, K., Ozawa, M., Sakoda, Y., Murakami, S.
PLoS ONE 11 ( 9 ) e0163828 2016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：PLoS ONE
© 2016 Horimoto et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Cattle are major reservoirs of the provisionally named influenza D virus, which is potentially involved in the bovine respiratory disease complex. Here, we conducted a serological survey for the influenza D virus in Japan, using archived bovine serum samples collected during 2010-2016 from several herds of apparently healthy cattle in various regions of the country. We found sero-positive cattle across all years and in all the prefectural regions tested, with a total positivity rate of 30.5%, although the positivity rates varied among regions (13.5-50.0%). There was no significant difference in positivity rates for Holstein and Japanese Black cattle. Positivity rates tended to increase with cattle age. The herds were clearly divided into two groups: those with a high positive rate and those with a low (or no) positive rate, indicating that horizontal transmission of the virus occurs readily within a herd. These data demonstrate that bovine influenza D viruses have been in circulation for at least 5 years countrywide, emphasizing its ubiquitous distribution in the cattle population of Japan.
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Yamazaki, W., Uemura, R., Sekiguchi, S., Dong, J., Watanabe, S., Kirino, Y., Mekata, H., Nonaka, N., Norimine, J., Sueyoshi, M., Goto, Y., Horii, Y., Kurogi, M., Yoshino, S., Misawa, N.
Journal of Applied Microbiology 120 ( 6 ) 1711 - 1722 2016年6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 Applied Microbiology
© 2016 The Society for Applied Microbiology. Aim: To elucidate the distribution and circulation dynamics of Campylobacter and Salmonella in Japanese chicken broiler flocks. Methods and Results: A 2-year investigation of the distribution of Campylobacter and Salmonella was conducted in 25 broiler flocks at nine farms in Japan from 2013 to 2014. Campylobacter and Salmonella tested positive in 11 (44·0%) and 24 (96·0%) broiler flocks respectively. One hundred and ninety-five Campylobacter and 184 Salmonella isolates were characterized into 12 Campylobacter (including two novel genotypes) and three Salmonella MLST genotypes. Only Salmonella isolation between caecal and environmental samples were significantly correlated. Further, one litter sample tested positive for Salmonella before new chicks were introduced. The Campylobacter strains rapidly lost culturability within 2-18 days; in contrast, the Salmonella strains survived from 64-211 days in artificially inoculated water samples. Conclusion: No persistent circulation-mediated Campylobacter contamination was observed. In contrast, circulation of Salmonella in broiler houses was seen, apparently due to the litter excreted from broiler flocks, as well as Salmonella-contaminated water and feed. Significance and Impact of the Study: This paper provides the distribution, genotypic data and circulation dynamics of Campylobacter and Salmonella as recently observed in Japanese chicken broiler farms.
DOI： 10.1111/jam.13141
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Six novel O genotypes from Shiga toxin-producing Escherichia coli 査読あり 国際誌
Iguchi, A., Iyoda, S., Seto, K., Nishii, H., Ohnishi, M., Mekata, H., Ogura, Y., Hayashi, T.
Frontiers in Microbiology 7 765 2016年5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 Microbiology
© 2016 Iguchi, Iyoda, Seto, Nishii, Ohnishi, Mekata, Ogura and Hayashi. Serotyping is one of the typing techniques used to classify strains within the same species. O-serogroup diversification shows a strong association with the genetic diversity of O-antigen biosynthesis genes. In a previous study, based on the O-antigen biosynthesis gene cluster (O-AGC) sequences of 184 known Escherichia coli O serogroups (from O1 to O187), we developed a comprehensive and practical molecular O serogrouping (O genotyping) platform using a polymerase chain reaction (PCR) method, named E. coli O-genotyping PCR. Although, the validation assay using the PCR system showed that most of the tested strains were successfully classified into one of the O genotypes, it was impossible to classify 6.1% (35/575) of the strains, suggesting the presence of novel O genotypes. In this study, we conducted sequence analysis of O-AGCs from O-genotype untypeable Shiga toxin-producing E. coli (STEC) strains and identified six novel O genotypes; OgN1, OgN8, OgN9, OgN10, OgN12 and OgN31, with unique wzx and/or wzy O-antigen processing gene sequences. Additionally, to identify these novel O-genotypes, we designed specific PCR primers. A screen of O genotypes using O-genotype untypeable strains showed 13 STEC strains were classified into five novel O genotypes. The O genotyping at the molecular level of the O-AGC would aid in the characterization of E. coli isolates and will assist future studies in STEC epidemiology and phylogeny.
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Horizontal transmission and phylogenetic analysis of bovine leukemia virus in two districts of Miyazaki, Japan. 査読あり 国際誌
Mekata H, Sekiguchi S, Konnai S, Kirino Y, Horii Y, Norimine J.
Journal of Veterinary Medical Science 77 ( 9 ) 1115 - 1120 2015年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.1292/jvms.14-0624
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Expression of regulatory dendritic cell-related cytokines in cattle experimentally infected with Trypanosoma evansi. 査読あり 国際誌
Mekata H, Murata S, Mingala CN, Ohashi K, Konnai S.
Journal of Veterinary Medical Science 77 ( 8 ) 1017 - 1019 2015年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.1292/jvms.15-0066
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Evaluation of the natural perinatal transmission of bovine leukaemia virus 査読あり 国際誌
Mekata H, Sekiguchi S, Konnai S, Kirino Y, Honkawa K, Nonaka N, Horii Y, Norimine J.
Veterinary Record 176 ( 10 ) 254 2015年3月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.1136/vr.102464
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Identification of O Serotypes, Genotypes, and Virulotypes of Shiga Toxin–Producing Escherichia coli Isolates, Including Non-O157 from Beef Cattle in Japan. 査読あり 国際誌
Mekata H, Iguchi A, Kawano K, Kirino Y, Kobayashi I, Misawa N.
Journal of Food Protection 77 ( 8 ) 1269 - 1274 2014年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Imamura S., Mekata H., Kirino Y., Nakamizo M., Hirano F., Kawanishi M., Yamamoto T., Nagai H., Kijima M., Kobayashi I.
International Journal of Applied Research in Veterinary Medicine 11 ( 3 ) 189 - 193 2013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：International Journal of Applied Research in Veterinary Medicine
To analyze the factors associated with an appearance of adverse events in calves following Histophilus somni vaccination, we investigated changes in rectal temperature, tumor necrosis factor-alpha (TNF-α) levels, and clinical signs in vaccinated Japanese Black calves (n=19). The average rectal temperature 24 hr post-vaccination was significantly higher in male calves compared with pre-vaccination. In contrast, the rectal temperature of female calves remained constant during the observation period. Febrile male calves aged over 9 months had inappetence, while the appetite of calves aged less than 8 months was normal. These results suggest that sex and age are associated with adverse effects elicited by H. somni vaccination. The amount of TNF-α in the peripheral blood derived from male calves was significantly lower than that derived from steer and female calves. Sex and/or age-related effects were not identified in reported cases of adverse events. Acute shock was the most common presentation in reported cases, typically when the vaccine was administered with another multivalent vaccine. Therefore, H. somni vaccination is considered safe when administered according to the manufacturer's instructions.
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Bovine whole-blood culture as a tool for the measurement of endotoxin activities in Gram-negative bacterial vaccines. 査読あり 国際誌
Imamura S, Nakamizo M, Kawanishi M, Nakajima N, Yamamoto K, Uchiyama M, Hirano F, Nagai H, Kijima M, Ikebuchi R, Mekata H, Murata S, Konnai S, Ohashi K
Veterinary immunology and immunopathology 153 ( 1-2 ) 153 - 8 2013年5月
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Isolation, cloning, and pathologic analysis of Trypanosoma evansi field isolates. 査読あり 国際誌
Mekata H, Konnai S, Mingala CN, Abes NS, Gutierrez CA, Dargantes AP, Witola WH, Inoue N, Onuma M, Murata S, Ohashi K
Parasitology Research 112 ( 4 ) 1513 - 1521 2013年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Transcriptional profiling of inflammatory cytokine genes in African buffaloes (Syncerus caffer) infected with Theileria parva. 査読あり 国際誌
Okagawa T, Konnai S, Mekata H, Githaka N, Suzuki S, Kariuki E, Gakuya F, Kanduma E, Shirai T, Ikebuchi R, Ikenaka Y, Ishizuka M, Murata S, Ohashi K
Veterinary immunology and immunopathology 148 ( 3-4 ) 373 - 9 2012年8月
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Kinetics of regulatory dendritic cells in inflammatory responses during Trypanosoma evansi infection. 査読あり 国際誌
Mekata H, Konnai S, Mingala CN, Abes NS, Gutierrez CA, Dargantes AP, Witola WH, Inoue N, Onuma M, Murata S, Ohashi K
Parasite immunology 34 318 - 329 2012年6月
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Molecular detection of trypanosomes in cattle in South America and genetic diversity of Trypanosoma evansi based on expression-site-associated gene 6. 査読あり 国際誌
Mekata H, Konnai S, Witola WH, Inoue N, Onuma M, Ohashi K
Infection, genetics and evolution 9 ( 6 ) 1301 - 5 2009年12月
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Development and application of a quantitative real-time PCR for the diagnosis of Surra in water buffaloes. 査読あり 国際誌
Konnai S, Mekata H, Mingala CN, Abes NS, Gutierrez CA, Herrera JR, Dargantes AP, Witola WH, Cruz LC, Inoue N, Onuma M, Ohashi K
Infection, genetics and evolution 9 ( 4 ) 449 - 52 2009年7月
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Prevalence and source of trypanosome infections in field-captured vector flies (Glossina pallidipes) in southeastern Zambia. 査読あり 国際誌
Mekata H, Konnai S, Simuunza M, Chembensofu M, Kano R, Witola WH, Tembo ME, Chitambo H, Inoue N, Onuma M, Ohashi K
Journal of Veterinary Medical Science 70 ( 9 ) 923 - 8 2008年9月
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Konnai, S., Mekata, H., Odbileg, R., Simuunza, M., Chembensof, M., Witola, W.H., Tembo, M.E., Chitambo, H., Inoue, N., Onuma, M., Ohashi, K.
Vector borne and zoonotic diseases 8 ( 4 ) 565 - 73 2008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：4
The prevalence of trypanosome infections in tsetse flies in the Chiawa area of Lower Zambezi in Zambia, with endemic trypanosomosis, was determined by a polymerase chain reaction (PCR) method that allowed the detection of trypanosome DNA and determination of the type of animal host fed on by the tsetse fly Glossina pallidipes, using tsetse-derived DNA extracts as templates. Ninety G. pallidipes (82 females and 8 males; 18.3%) of the 492 flies captured by baited biconical traps tested positive for the presence of Trypanosoma brucei species genomic DNA. Of the 90 T. brucei-positive flies, 47 (52.2%) also tested positive for vertebrate mitochondrial DNA. Sequence analysis of the vertebrate mitochondrial DNA amplicons established that they originated from 8 different vertebrate species, namely, human (Homo sapiens), African elephant (Loxodonta cyclotis), African buffalo (Syncerus caffer), waterbuck (Kobus ellipsiprymnus), roan antelope (Hippotragus equinus), greater kudu (Tragelaphus strepsiceros), warthog (Phacochoerus africanus), and goat (Capra hircus). Furthermore, to investigate the prevalence of trypanosome infections in domestic goats in the same area where trypanosomes had been detected in tsetse files, a total of 86 goats were randomly selected from 6 different herds. Among the selected goats, 36 (41.9%) were found to be positive for T. brucei species. This combined detection method would be an ideal approach not only for mass screening for infection prevalence in tsetse populations, but also for the prediction of natural reservoirs in areas endemic for trypanosomosis.