Equine herpes myeloencephalopathy has been confirmed in the Regional Municipality of Halton, Ontario. On September 2, 2025, a 23 year old mare developed
acute neurologic signs (recumbency). The horse is affected and alive, and receiving supporting treatment. One additional horse was exposed. The farm owner has implemented voluntary animal movement restrictions and biosecurity measures. To see past and present equine herpesvirus cases in Ontario go to:
https://www.oahn.ca/resources/ontario-equine-disease-alerts/ and enter the disease surveillance portal.