Disease Alerts

Number Confirmed: 1;
Age: 7; Gender: Mare; Breed: Holsteiner; Clinical Signs: fever, mild neurological signs; Confirmation Date: 6/6/2022; Horse Status: Affected And Alive; Vaccination Status: Vaccinated;
Notes: A 7-year-old Holsteiner mare in San Mateo County displaying fever followed by mild neurological signs was confirmed positive for Equine Herpesvirus Myeloencephalopathy (EHM) secondary to EHV-1 (non-neuropathogenic strain) on June 6th. She was referred to a veterinary hospital at onset of neurological signs, and isolated and quarantined. She attended an equine event in Sacramento County the weekend prior, asymptomatic throughout the show, and departing on Saturday May 28th with 5 other horses from her home barn. Event management has notified all show attendees to observe best biosecurity practices and isolate any horses returning from the event for 14 days following departure from the show grounds. CDFA was onsite at the index mare’s home premises, and 9 potentially exposed horses were also quarantined and enhanced biosecurity measures implemented. There is no known epidemiological link between this case and the previously confirmed active EHM incident in San Mateo County. CDFA will actively monitor the situation. For more information go to EHM factsheet.