Editor’s Note: This article is part of TheHorse.com’s ongoing coverage of topics presented at the 9th International Conference on Equine Infectious Diseases, held Oct. 21-26 in Lexington, Ky.

Although equine coronavirus is a commonly identified in foals–found in 27% of healthy and 29% of sick animals, according to one study– its significance as a gastrointestinal pathogen is still unclear. However, accumulating evidence indicates that coronavirus is associated with recent enteric disease outbreaks in adult horses.

Ron Vin, DVM, Dipl. ACVIM, an equine practitioner at Myhre Equine Clinic in Rochester, N.H., and a consultant for IDEXX Laboratories, and Nicola Pusterla, , DVM, PhD, Dipl. ACVIM, a professor in the University of California, Davis, School of Veterinary Medicine Department of Medicine and Epidemiology, both presented lectures on the topic at the 9th International Conference on Equine Infectious Diseases, held Oct. 21-26 in Lexington, Ky.

Veterinarians have long suspected the relationship between coronavirus and enteric disease (intestinal issues, characterized by diarrhea and fever, among other clinical signs) in foals. However Vin relayed that a recent major outbreak in adult horses was reported in Japan in 2011. There, 132 horses, aged 2 to 4 years, residing at a draft horse racetrack that housed about 600 animals, developed fever and diarrhea that persisted for two to four days. The clinical signs were self-limiting (most cleared up in a few days), and the outbreak lasted only a few months, Vin said