UPDATE March 29, 2021: The quarantine on the property has been released since there were no additional cases for fourteen (14) days on the premise.

The California Department of Food and Agriculture (CDFA) confirmed that a 21-year-old Warmblood mare at a boarding facility in Sonoma County has been confirmed positive for neurologic equine herpesvirus (EHV-1, also known as equine herpesvirus myeloencephalopathy or EHM). 

The mare had onset of clinical signs on March 13 that included ataxia, urine dribbling and ataxia in all four limbs. She was confirmed positive on March 15. At the time of this report, the vaccinated mare was affected and alive. The mare is being treated in isolation at a veterinary hospital. 

A total of 40 horses on the home premises have been quarantined with enhanced biosecurity measures and twice daily temperature monitoring. 

There is no known risk of exposure out of this facility to any local events. The clinical horse has no recent travel history and no links to any other EHV-1 cases. 

CDFA will continue to actively monitor exposed horses.

Information for this report was provided by the Equine Disease Communication Center.