The Equine Disease Communication Center (EDCC) has reported that three horses in Erie County, New York, tested positive for equine herpesvirus-1 (EHV-1) last week.

“On May 6 three aged mares, all displaying neurologic symptoms, were confirmed positive for equine herpesvirus-1 on PCR,” the EDCC reported. “Neurologic symptoms along with a positive EHV-1 PCR meets (New York’s) case definition for equine herpes myeloencephalopathy (EHM). Both EHV-1 and EHM are reportable in New York.

“All three mares are from the same farm,” the statement continued. “One of those mares has been euthanized for humane reasons. The entire farm has been quarantined. Biosecurity measures and twice daily temperature monitoring are in place. New York State Department of Agriculture and Markets is continuing to monitor the situation and look for other potentially exposed animals.”

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 myeloencephalopathy. In many horses, fever is the only sign of EHV-1 infection, which can go undetected