A sixth California horse has tested positive for equine herpesvirus-1 (EHV-1), animal health officials in that state announced Nov. 7.

On Nov. 3, the California Department of Food and Agriculture (CDFA) reported that two Saddlebred horses in Los Angeles County had tested positive for non-neuropathogenic EHV-1. The next day, the CDFA issued an update indicating that three more horses at the index facility  had tested positive.

On Nov. 7, the CDFA said an additional horse had been confirmed positive.

“At the Los Angeles Equestrian Center, a febrile horse displaying mild neurologic signs has been confirmed positive for the non-neuropathogenic strain of equine herpesvirus-1,” the agency said. “One of the six horses was euthanized on Nov. 3 due to the severity of clinical signs. All other confirmed positive horses remain in isolation and under quarantine. All exposed horses remain under quarantine and temperatures are being taken twice daily.

“Four of the six confirmed positive horses participated in a horse show in Las Vegas, Nevada, on Oct. 24-29,” the CDFA added. “At this time, no additional EHV-1 cases have been confirmed in horses that exhibited at the Las Vegas horse show. CDFA has confirmed that the host facility has taken biosecurity measures of thorough cleaning and disinfection of the show facility.”

Veterinarians from the CDFA Animal Health Branch continue to monitor the quarantine and