The California Department of Food and Agriculture (CDFA) reported March 19 that a stallion from southern California has tested positive for equine herpesvirus-1 (EHV-1).

"A Warmblood stallion in San Diego County displaying mild neurologic signs has been confirmed positive for the non-neuropathogenic strain of EHV-1," a statement posted on the organization’s website read. "This strain of virus is responsible for the more common respiratory EHV-1 cases. A small percentage of non-neuropathogenic EHV-1 infected horses can display neurologic signs and are classified as equine herpes myeloencephalopathy (EHM) cases which are a reportable condition in California.

"The positive horse has been quarantined and is under veterinary care," the statement continued. "CDFA is working to contact exposed horse owners and recommends isolation, twice daily temperature monitoring, and implementation of proper biosecurity."

Earlier this month in a different region of the state, a 3-year-old Thoroughbred filly was euthanized at Santa Anita Park, in Arcadia, Calif., after developing a fever and subsequent neurologic signs. Necropsy results showed histologic lesions compatible with neurotrophic EHV-1, the CDFA reported. The CDFA said March 19 that "all horses on the premises are being monitored and, as of this time, no other horses have developed a fever or other symptoms compatible with EHV-1. CDFA will continue to monitor the situation