The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) has been notified of a case of Equine Herpes Myeloencephalopathy (EHM), caused by Equine Herpes Virus 1 (EHV-1), in the Ottawa region. The horse is currently receiving veterinary care at a referral center. OMAFRA has notified all veterinarians associated with animals that had contact with the suspect case in the preceding 10-14 days.
EHV-1 infection in horses can cause respiratory disease, abortion, neonatal foal death, and/or neurological disease. Disease associated with EHV-1 infection is not federally reportable but detection of the neuropathogenic strain is immediately notifiable by laboratories under the reporting regulation of the provincial Animal Health Act. Attending veterinarians suspicious of EHM should contact OMAFRA as soon as possible.
Because infected horses may show no clinical signs, but still shed the virus, the temperature of suspect animals should be monitored twice daily for 14 -21 days and any abnormalities discussed with a veterinarian. Neurological signs, if they develop, 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 this from other serious neurological diseases, such as rabies.