Dead crow tests positive for West Nile virus in southwestern Ontario
As of June 2, 2026, no human cases have been reported in the region, but health officials say a positive local bird suggests the mosquito-transmitted virus may be present.
A dead crow found in Guelph, Ont., has tested positive for West Nile virus (WNV), according to a Tuesday press release from Wellington-Dufferin-Guelph Public Health.
As of June 2, 2026, no human cases have been reported in the region, but health officials say a positive local bird suggests the mosquito-transmitted virus may be present.
Residents are urged to take precautions to reduce the risk of mosquito bites.
“Although the risk in our region is low, WNV is still present, and people should stay vigilant,” Dr. Matthew Tenenbaum, Associate Medical Officer of Health, Wellington-Dufferin-Guelph Public Health, says in the press release.
“We continue to monitor and control local mosquito populations, but it is important for everyone to take the basic steps that help prevent mosquito bites.”
What is West Nile virus?
WNV is an infection spread through the bite of an infected mosquito. It is present across Canada.
The risk is highest in summer and early fall, when mosquitoes are most active.
Symptoms of WNV can range from mild to severe, according to the Government of Canada. Up to 80 per cent of people who are infected present no symptoms.
Mild symptoms can include:
Fever.
Headache.
Body aches.
Mild rash.
Swollen lymph glands.
Symptoms typically appear 2 to 15 days post-infection.
Anyone infected with the virus is at risk of developing more severe health complications, although this occurs in less than one per cent of infected patients.
If you suspect you have a West Nile virus infection, contact a health care provider immediately.
West Nile Virus: By the numbers
In 2024, 177 human cases of WNV were reported across the country, plus an additional 13 cases that were contracted while travelling abroad, according to Health Canada. Of those cases, one person died.
Health Canada says 2024 was a higher-than-average year for WNV, with total annual case counts typically ranging from 50 to 100 infections.
Prevention
Toronto Public Health recommends the following prevention tips to protect against mosquito bites:
Wear light-coloured, long-sleeved shirts and pants when outdoors.
Apply insect repellent containing DEET or icaridin and follow the manufacturer's instructions.
Take extra care during dusk and dawn, when mosquitoes are most active.
Remove standing water from your property, where mosquitoes can breed.
Ensure your home has tight-fitting screens on windows and doors.