Fukumoto Natsuko, Bannai Hiroshi, Kawanishi Nanako, Shibata Makoto, Kishi Daiki, Kambayashi Yoshinori, Tsujimura Koji, Nemoto Manabu
Athena Integrative Veterinary Care for Ban'ei Race Horse.
Equine Research Institute, Japan Racing Association.
J Vet Med Sci. 2025 Aug 4. doi: 10.1292/jvms.25-0271.
Equine coronavirus (ECoV) causes fever, anorexia and sometimes enteric signs (e.g. diarrhea) in adult horses. Three ECoV outbreaks among draft horses at the same Japanese racecourse have been reported previously, in 2004, 2009 and 2012. We describe the epidemiological, clinical and genetic features of the fourth ECoV outbreak at the same racecourse in 2025. In January 2025, a sudden increase in the number of draft horses showing various combinations of fever, anorexia and enteric signs was observed at Obihiro Racecourse, in Hokkaido, Japan. Of about 800 horses, 176 showed clinical signs. Specifically, 83.5% (147/176) horses had fever, 98.9% (174/176) were anorexic, and 10.2% (18/176) had enteric signs. Real-time reverse transcription -polymerase chain reaction detected ECoV RNA in 23 of 26 horses. Seroconversion to ECoV was confirmed in 25 of 26 horses by neutralization assay. The results indicate that all 26 horses tested were infected with ECoV. Molecular analyses showed that the spike and nucleocapsid genes were highly conserved compared to other ECoVs. However, phylogenetic analysis showed that these genes of the 2025 virus did not form a group with the strains detected in the previous three outbreaks. These results indicate that ECoV was the cause of the sudden increase in the number of draft horses with fever, anorexia and enteric signs. Although the origin of the 2025 virus is unknown, this outbreak was likely caused by a virus different from the one that caused the previous outbreaks.
马冠状病毒（ECoV）可导致成年马发热、厌食，有时还会出现肠道症状（如腹泻）。此前曾报道2004年、2009年和2012年在日本同一赛马场的役用马中发生过三次ECoV疫情。我们描述了2025年在同一赛马场发生的第四次ECoV疫情的流行病学、临床和基因特征。2025年1月，在日本北海道带广赛马场观察到役用马中出现发热、厌食和肠道症状等多种组合的马匹数量突然增加。在约800匹马中，176匹出现临床症状。具体而言，83.5%（147/176）的马发热，98.9%（174/176）的马厌食，10.2%（18/176）的马有肠道症状。实时逆转录-聚合酶链反应在26匹马中的23匹检测到ECoV RNA。通过中和试验在26匹马中的25匹确认了对ECoV的血清转化。结果表明，所有26匹受试马均感染了ECoV。分子分析表明，与其他ECoV相比，刺突蛋白和核衣壳基因高度保守。然而，系统发育分析表明，2025年病毒的这些基因与前三次疫情中检测到的毒株未形成一个群组。这些结果表明，ECoV是导致役用马出现发热、厌食和肠道症状数量突然增加的原因。尽管2025年病毒的起源不明，但此次疫情可能是由一种与之前疫情所涉病毒不同的病毒引起的。
