On March 5, 2018, Arizona Department of Agriculture (AZDA) Director Mark Killian ordered the quarantine of a cutting horse training facility in northern Maricopa County after a nasal swab on a gelding tested positive for equine herpesvirus-1 (EHV-1) “wild strain.”

On Friday, March 2, 2018, Peter Mundschenk, DVM, the Arizona state veterinarian, received notification confirming the diagnosis of equine herpes myeloencephalopathy (EHM) in a Quarter Horse gelding with a positive nasal swab of EHV-1. This horse had been at South Point Arena in Las Vegas earlier in the month for a cutting horse event and also attended the Arizona Cutting Horse Association (ACHA) show in Queen Creek the weekend prior to developing neurologic signs.

The ACHA is also reaching out to all contestants to advise them to observe all horses that attended the events for signs of illness and to contact their veterinarians for testing, as they might have been exposed. The event center at Queen Creek is in the process of doing a second disinfection of the facility.

Equine herpesvirus-1 is highly contagious among horses but poses no threat to humans. The symptoms in horses might include a fever, nasal discharge, leg edema (fluid swelling), wobbly gait, hind-end weakness, dribbling of urine, and diminished tail tone. The virus spreads easily by airborne transmission, horse-to-horse contact, and contact with nasal secretions on equipment, tack, feed, and other surfaces. Caretakers can spread the virus to horses if their hands, clothing, shoes, or vehicles are contaminated