The affected horse, an undervaccinated yearling Thoroughbred colt in Sacramento County, began showing clinical signs on Nov. 3. | Photo: Wikimedia Commons

On Nov. 13, officials at the California Department of Food and Agriculture (CDFA) confirmed a horse in Sacramento County with West Nile virus (WNV). The affected horse, an undervaccinated yearling Thoroughbred colt, began showing clinical signs on Nov. 3. Signs consisted of ataxia (loss of control of bodily movements) and hind-limb neurologic signs. The colt is recovering.

According to CDFA, this is California’s 19th confirmed equine case of WNV in 2020. Other counties with confirmed cases include: Amador (2), Butte (1), Glenn (1), Kinds (1), Merced (1), Modoc (1), Nevada (1), Riverside (2), San Bernardino (1), San Joaquin (4), and Stanislaus (3).

Of the 19 confirmed cases, 13 were unvaccinated, four had unknown vaccination histories, and two were vaccinated. Fourteen are alive, one died, and four were euthanized