Equine herpesvirus-1 is responsible for the clinical disease known as Equine Herpesvirus Myeloencephalopathy (EHM).
In 2023 the Office of the Chief Provincial Veterinarian (OCPV) was notified of four cases of EHM in Alberta and in 2024, there was one notification. The OCPV has recently been made aware of one case in 2025.
The OCPV has also been made aware that several cases are being detected in the U.S. As of November 21, fifteen cases had been reported in the U.S. Some events or shows are being cancelled to minimize risk of horses becoming exposed and to help reduce the spread while others are planning to proceed. Those planning to attend should reach out to organizers to check on event status, risk and biosecurity measures in place.
Resources for veterinarians and horse owners:
- Government of Alberta: Equine herpesvirus-1
- Canadian Food Inspection Agency: Equine herpes myeloencephalopathy (EHM) fact sheet
- Texas Animal Health Commission: Equine herpes myeloencephalopathy fact sheet