Disease alerts - West Nile Virus in Ontario, August 15, 2025 - West Nile Virus in Ontario, August 15, 2025 - West Nile Virus in Ontario, August 15, 2025

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Regulatory Category- Federal:

Immediately Notifiable

Regulatory Category- Province or Territory:

Immediately Notifiable

Animal Type:

Equine

Susceptible Animal Types:

Avian (Non-domestic);
Equine;
Human

Animal Class:

Terrestrial

Disease Agent:

West nile virus

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/15/2025

End Date

Aug/15/2025

Website

Equine Disease Communication Center

West Nile Virus in Ontario, August 15, 2025

Ontario Ministry of Agriculture, Food and Agribusiness (OMAFA)

West Nile Virus has been confirmed in Regional Municipality of Waterloo, Ontario. On August 9, 2025, a yearling Standardbred filly developed acute neurologic signs (ataxia, blindness, recumbency) and was euthanized. She tested positive for West Nile Virus by PCR. The horse was not vaccinated against West Nile Virus. This is the first confirmed case of equine West Nile Virus in Ontario this year. To see past and present West Nile Virus cases in Ontario go to: https://www.oahn.ca/resources/ontario-equine-disease-alerts/ and enter the disease surveillance portal.