West Nile Virus (WNV) has been confirmed in the District of Parry Sound, Ontario. On August 21, 2025, a 22 year old mixed breed mare developed neurologic signs (muscle fasciculations, hyperesthesia, ataxia). The horse is recovering. The horse was not vaccinated against WNV, but was vaccinated against other core diseases (rabies, Eastern and Western Equine Encephalitis, and tetanus).
This is the fifth 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.