As excitement builds during the first days of the equestrian portion of the Pan Am Games, Ontario agriculture officials have announced a case of equine herpes myeloencephalopathy (EHM). EHM is a neurological disease caused by the equine herpes virus (EHV-1).
The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) states the horse, located in the Ottawa region, is receiving veterinary care at a referral center. The horse is reportedly not near the Pan Am equestrian venue. OMAFRA officials have notified the veterinarians of animals that came in contact with the horse.
Infected horses may not show clinical signs, but still have the ability to shed the virus. The temperature of suspect animals should be monitored twice daily for 14 -21 days and any abnormalities discussed with a veterinarian.
Symptoms that should alert horse owners to the possibility of EHM may include loss of balance, hind-limb weakness, recumbency, difficulty urinating, decreased tail tone and depression. It is important that a veterinarian assess suspect cases of EHM, since it can be difficult to distinguish from other neurological diseases.
EHV-1 is easily spread by nose-to-nose or close contact with an infectious horse, by sharing contaminated equipment (bits, buckets, towels etc.) or by the clothing, hands or equipment of people who recently had contact with an infectious horse. Routine biosecurity measures should be in place to prevent a disease outbreak. Special attention should be given to cleaning and disinfecting trailers.
Current EHV-1 vaccines may reduce viral shedding, but are not protective against the neurological form of the disease.