Animal health officials in Maryland reported April 20 that a Howard County horse has tested positive for equine herpesvirus-1 (EHV-1).

The Maryland Department of Agriculture said the affected horse tested positive for non-neuropathic EHV-1 and was euthanized by a private veterinarian. Diagnosis was confirmed on April 18 by the Maryland Department of Agriculture Frederick Animal Health Laboratory.

The farm is presently under a 30-day investigational hold and strict biosecurity measures are in place while Department of Agriculture inspectors perform additional epidemiologic and infectious disease testing. Stables near the one where the sick horse resided are being notified of the situation and owners are cautioned to monitor horses at their premises carefully.

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 (the neurologic form). In many horses, fever is the only sign of EHV-1 infection, which can go undetected