Forty-eight horses at the affected horse’s Sonoma County premises are under quarantine after being exposed to the EHV-1-positive mare. | Photo: Wikimedia Commons

On April 8 officials at the California Department of Food and Agriculture (CDFA) confirmed a 10-year-old Warmblood mare in Sonoma County positive for equine herpesvirus-1 (EHV-1). The mare exhibited neurologic signs, which included ataxia (incoordination), dribbling urine, and nasal discharge but no fever, on April 6. She is reported as affected and alive, and 48 additional horses at her home premises are quarantined and being monitored twice daily for elevated temperatures. Enhanced biosecurity measures have also been enacted.

The CDFA stated that this case is not related to the EHV-1 quarantine enacted at an Alameda County premises on March 14.

EHV 101

Herpesvirus is highly contagious among horses and can cause a variety of ailments in equids, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and equine herpesvirus myeloencephalitis (EHM, the neurologic form)