In many horses, the only sign of EHV-1 infection is fever, which can go undetected. | Photo: Kevin Thompson/The Horse

The Equine Disease Communication Center (EDCC) reported May 23 that a horse from York County, Maine, has been diagnosed with equine herpesvirus myeloencephalopathy (EHM), the neurologic form of equine herpesvirus-1 (EHV-1).

“One Standardbred horse showed an onset of clinical signs on May 10, including acute neurologic signs rapidly progressing to recumbency,” the EDCC said. “The case was confirmed with testing sent to the National Veterinary Services Laboratory, and a quarantine was initiated on May 15. The index case was euthanized and 12 horses remain in quarantine on the facility.”

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