Horse Owners: EHV-1 Alert

One case of Equine Herpesvirus Myeloencephalopathy (EHM) has been confirmed by the Office of the Provincial Veterinarian in 2025. EHM is the neurological form of Equine Herpesvirus-1 (EHV-1) and is a contagious virus that can affect the brain and nerves. While this is not a new disease it MUST be reported and monitored under Alberta’s Animal Health Act.

Clinical signs of EHV-1 depend on the strain of the virus but can include:

  • fever
  • respiratory disease
  • abortion
  • death in young foals
  • neurological problems

While vaccination helps reduce the risk it does not completely prevent EHV-1. It is best to talk to your veterinarian about vaccinations and to stay informed about outbreaks. An effective Biosecurity Plan is essential to prevent infectious diseases like EHM.

If you suspect EHV-1 in your herd, call your veterinarian right away. All suspected or confirmed cases must be reported to the Office of the Chief Provincial Veterinarian within 24 hours.

Government of Canada EHM Fact Sheet

Government of Alberta EHV-1 Information