EHM confirmed in Bowman County horse

BISMARCK – Equine herpesvirus myeloencephalopathy (EHM) has been confirmed in a well-known Bowman County barrel-racing horse. The horse became notably ill on Thursday, April 19. The disease rapidly progressed, resulting in euthanization that same day. Confirmatory lab results were received Friday evening.

Horses that were exposed to the positive horse within 72 hours prior to the onset of clinical illness have been quarantined. Owners of other horses that may have had contact with the affected horse prior to that period are being advised to consult with their local veterinarian, monitor their horses and restrict travel.

EHM is caused by equine herpesvirus-1 (EHV-1) and occasionally equine herpesvirus-4 (EHV-4). EHV-1 is not uncommon and can cause respiratory disease, abortion, neonatal death and rarely the neurologic form of the disease, EHM. Vaccines are available for the respiratory and reproductive forms of EHV-1. They do not reliably prevent the neurologic form (EHM), but may offer some level of protection. Vaccinating horses after exposure is not recommended.

“With summer coming, many horses will be moving to events around the region,” said State Veterinarian Dr. Susan Keller. “Care should be taken when co-mingling horses to minimize the chances of contracting the disease.”

EHV-1 can be spread through the air, contaminated equipment, clothing and hands. Biosecurity measures that can reduce the risk of spreading the disease include avoiding shared food or water containers and preventing nose-to-nose contact.

Out-of-state horses and other equines entering North Dakota for any length of time must be accompanied by a certificate of veterinary inspection.

“Certificates of veterinary inspection reduce the risk of introduction of clinical disease and help us better monitor the movement of equines into North Dakota,” said Dr. Keller. “We use that information to report disease risks and findings to veterinarians and horse owners in North Dakota.”

Although highly infectious and contagious among horses, EHV-1 poses no threat to human health.