Laboratory confirmation of a horse infected with Equine Herpesvirus (EHV1) Myeloencephalopathy in Sheridan County was received by Wyoming Livestock Board (WLSB) staff veterinarians on Wednesday, March 14. The horse has been quarantined to its premise in Sheridan County with 12 other horses.
EHV1 is the very common Rhinopneumonitis virus which typically causes mild respiratory symptoms in infected horses. In rare cases, the virus may cause neurologic symptoms.
The affected horse began showing neurologic signs on Sunday, March 11 while competing at a barrel racing event at the Cam-plex facility in Gillette. Owners of any horses attending that event should consult with their veterinarians and take precautions regarding exposure risk. At a minimum, these precautions should include close monitoring of the horses and checking their temperatures at least twice daily. If any of the horses show neurologic signs or fever, the owner needs to contact his/her veterinarian and the Wyoming Livestock Board.
The source of the infection in the quarantined horse is unknown; however, this horse did compete at two other earlier events, including one at the Central Wyoming Fairgrounds in Casper on Thursday, March 1, and one at Laramie County Community College, Friday, March 2 – Sunday, March 4. “Horses at those events may have been exposed,” explained Wyoming assistant state field veterinarian Dr. Thach Winslow, “but keep in mind that the incubation period [time from exposure to exhibiting signs] for the disease is less than 14 days, in which case clinical signs should have already been apparent if horses were exposed at either of those events.”
More information on Equine Herpes Virus can be obtained by contacting the Wyoming Livestock Board Field Office at 307-857-4140.
