West Nile Virus (WNV) has been confirmed at a farm in Durham, Ontario. On August 25, 2026, a 19 year old gelding developed acute neurologic signs including ataxia and falling down and was euthanized. Blood serum tested positive for WNV IgM. The horse was not vaccinated against WNV.
This is the third confirmed case of equine WNV in Ontario this year. To see past and present WNV cases in Ontario go to: https://www.oahn.ca/resources/ontario-equine-disease-alerts/ and enter the disease surveillance portal.