A brief announcement was issued by the California Department of Food and Agriculture on Friday, July 5:

“A four year old Quarter Horse mare in Contra Costa County displaying severe neurologic signs has been confirmed positive for the neuropathogenic strain of Equine Herpesvirus -1 ( EHV-1). Due to the severity of clinical signs in this case of Equine Herpes Myeloencephalopathy (EHM), the mare was euthanized.

“Initial epidemiologic investigation indicates no exposed horses as the mare was the sole horse on a pasture with cattle. CDFA continues with the epidemiologic investigation and to monitor the situation.”

(end of statement)

For reference, Contra Costa County is west of San Francisco. No exact location has been given for the premises where the horse was located. This case is the fourth outbreak of the neurological form of EHV in California this year, but the other three cases were located in the southern part of the state.

CDFA has no recommendations for the cancellation of any equine events.