The Equine Disease Communication Center confirmed on March 11 that four horses have tested positive for equine herpesvirus at a barn in Brewster, New York. Two were diagnosed with equine herpesvirus myeloencephalopathy, the neurologic strain of the disease, and two tested positive for EHV-1.
The origin of the cases is still unknown, and the stable is under quarantine.
One of the positive EHM horses competed at Old Salem Farm in North Salem, New York. It arrived March 4, competed in the equitation on March 5, and returned home that evening. That horse began exhibiting symptoms on March 7, and the second EHM-positive horse showed symptoms on March 8. The two EHV-1 cases were tested due to their proximity to the index case.
The Old Salem Farm show facility is being disinfected, and show management is following EHV-1 biosecurity protocols.