California: 9 veterinary cases confirmed in new EHV-1 outbreak

Orange County, Calif.

— A new outbreak of the neurological form of equine herpesvirus (EHV-1) has been confirmed by California veterinary authorities. A total of nine cases have been confirmed at a single location since Jan. 11.

The latest case was confirmed today, and officials with the California Department of Food and Agriculture (CDFA) Animal Health Branch reports an Orange County ranch remains under quarantine.

The first case identified the ranch appeared in a gelding displaying neurologic signs, according to CDFA. The gelding was later confirmed positive for the neuropathogenic strain of EHV-1, was isolated, quarantined and placed under veterinary care.

Potentially exposed horses on the premises are being monitored, and a full epidemiologic investigation has been initiated by veterinary officials with CDFA.

CDFA says the source of the outbreak has yet to be identified, but the initial investigation reveals no link to three outbreaks in 2011—one in May that sickened nearly 90 horses across 10 Western states and two other smaller outbreaks later in the year.