A newly confirmed case of Equine Herpesvirus Myeloencephalopathy (EHM) in Alberta has raised concerns among local horse owners. EHM is the neurological form of Equine Herpesvirus-1 (EHV-1), a contagious virus that can cause fever, respiratory signs, and in some cases, serious neurologic illness.
Recent Detection in Alberta
The Office of the Chief Provincial Veterinarian has confirmed one case of EHM in 2025. The affected horse had no travel history outside Alberta, developed sudden neurologic signs, and is now recovering under veterinary care.
Although the horse was fully vaccinated, vaccination only reduces risk and severity—it does not completely prevent EHM.
A Look at Alberta’s Recent History
EHM remains uncommon in Alberta, but cases do occur periodically:
- 2023: Four confirmed cases
- 2024: One confirmed case
- 2025: One case to date
Alberta tracks these detections to monitor trends, but no provincial movement restrictions are placed when cases occur.
Activity in the United States (U.S.)
Fifteen EHM cases have been reported in the U.S. this month. Some shows have cancelled or strengthened biosecurity protocols. Anyone travelling with horses is encouraged to check event status and precautions in advance.
How Alberta Monitors EHM
EHM is a provincially notifiable disease, meaning veterinarians must report confirmed cases. Alberta does not impose movement restrictions but monitors cases to track trends and alert the equine community when needed.
What Horse Owners Can Do Right Now
- Strengthen barn biosecurity: Isolate new or returning horses for 10–14 days, reduce nose-to-nose contact, and avoid letting visiting horses mix directly with resident animals.
- Manage equipment and movement: Do not share water buckets, tack, grooming tools, or feed tubs. If sharing is unavoidable, disinfect thoroughly between horses.
- Monitor temperatures and health: Take temperatures daily when returning from events. A fever is often the earliest sign of EHV-1.
- Limit travel during increased risk periods: Consider postponing non-essential trips to multi-horse events until case numbers stabilize.
- Maintain vaccinations: Vaccines help reduce severity and viral shedding, adding protection at the herd level.
- Have an isolation plan ready: Identify a stall or pen where a sick horse can be safely separated while awaiting veterinary assessment.
More Information
Visit the below resources for more information on risks, symptoms, and prevention: