West Nile Virus (WNV) is a mosquito-borne virus that can cause swelling and inflammation of the brain and spinal cord in horses, birds and humans. Only specific species of mosquitoes spread WNV. In Alberta, the species of mosquito of concern is Culex tarsalis, which becomes infected when feeding on infected wild birds. Only domestic geese, horses, mules and donkeys appear to be severely affected by WNV, and may develop clinical disease. Preventive measures should be discussed with your local veterinarian.

West Nile Virus is a provincially notifiable disease for horses, donkeys and mules.

West Nile Virus fact sheet

  • Fact sheet about West Nile Virus, including specifics relating to spread and testing in horses, and past confirmed cases in Alberta and Canada.