The California Department of Food and Agriculture (CDFA) confirmed a case of neurologic equine herpesvirus (EHV-1, also known as equine herpesvirus myeloencephalopathy or EHM) at a boarding facility in San Mateo County.

The 19-year-old Thoroughbred mare had onset of clinical signs on May 28 that included fever, limb edema, ataxia and recumbency. She was confirmed with EHV-1 on June 2. The vaccinated mare was euthanized. She had no recent travel or show history.She had no recent travel or show history and was vaccinated for EHV-1. She was euthanized on June 2 due to severity of clinical signs.

300 horses at the mare’s home premises in San Mateo County have been quarantined, and CDFA will continue to closely monitor the situation.

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

For more information on neurologic equine herpesvirus check out this EDCC Fact Sheet.