Eastern Equine Encephalitis (EEE) has been confirmed in Wellington County, Ontario. On August 2, 2025, an 8 year old Shetland Pony mare developed a fever and was lethargic. By August 3, 2025, the mare had developed acute neurologic signs (head-pressing, ataxia) and was referred to an equine hospital where she was reported to have a signs of cranial nerve involvement (horizontal nystagmus, head tilt, neck to the right and absent menace response). The horse was euthanized. The horse was not vaccinated against EEE. This is the second confirmed EEE case in Ontario this year and the second for Wellington County. To see past and present EEE cases in Ontario go to:
https://www.oahn.ca/resources/ontario-equine-disease-alerts/ and enter the disease surveillance portal.