Disease alerts - Eastern Equine Encephalitis in Ontario, August 26, 2025 - Eastern Equine Encephalitis in Ontario, August 26, 2025 - Eastern Equine Encephalitis in Ontario, August 26, 2025

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Regulatory Category- Federal:

Immediately Notifiable

Regulatory Category- Province or Territory:

Immediately Notifiable

Animal Type:

Equine

Susceptible Animal Types:

Equine

Animal Class:

Terrestrial

Disease Agent:

Eastern equine encephalomyelitis

Disease Agent Type:

Virus

Organization:

Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA)

Region:

Ontario

Event Size:

1 individual

Problem(s):

Nervous systems signs

Topics:

Endemic;
Vector/Vector-borne

Start Date

Aug/26/2025

End Date

Aug/26/2025

Website

Equine Disease Communication Center

Eastern Equine Encephalitis in Ontario, August 26, 2025

Ontario Ministry of Agriculture, Food and Agribusiness (OMAFA)

Eastern Equine Encephalitis (EEE) has been confirmed in the City of Ottawa, Ontario. On August 12, 2025, a 14 year old Belgian mare went off feed, and the next day developed acute neurologic signs (ataxia progressing to recumbency and nystagmus) and fever. The horse was euthanized. Serum EEE IgM ELISA was positive. The horse was undervaccinated. This is the fourth confirmed equine EEE case in Ontario this year. 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.