Outbreaks | Equine Disease Communication Center

Updates on current disease outbreaks are listed here as they occur and will include the date listed, disease name, location and current status. Specific premises will not be named but the general location by town, county and state will be listed. When locations, events or horses are at risk they will be listed. Updates will be posted as they are received.

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West Nile Virus

Regional Municipality of Waterloo, ON

Outbreak Identifier: 7041

Alert ID: 4562

September 08, 2025

Confirmed Case(s) - No Quarantine

Source: OMAFA

Number Confirmed: 1;
Number Exposed: Unknown;
Facility Type: Farm;

Horse 1:
Age: 6; Gender: Mare; Breed: Mixed breed; Onset of Clinical Signs: 8/30/2025; Clinical Signs: This mare presented to a referral hospital with anorexia, fever, diarrhea and neurologic signs (ataxia, sensitive to tough, cranial nerve signs). She responded to treatment and has returned home. Serum was positive on WNV IgM ELISA.; Horse Status: Recovering; Vaccination Status: Unvaccinated;

Comments: This is the fourth 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;

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