West Nile virus detected in Ottawa mosquitoes as summer season peaks
Ottawa Public Health confirms first positive mosquito pool of 2026. No human cases reported yet, but residents urged to protect themselves through fall.
Sources · local media reports
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Ottawa Public Health has confirmed the first positive mosquito pool for West Nile virus this year, marking the start of the season's transmission risk.
The detection came through routine mosquito trapping and testing that began in June. As of July 26, Ontario had reported two human cases statewide, but none in Ottawa so far. The virus remains a threat until the first hard frosts arrive in fall.
West Nile is spread primarily by the northern house mosquito. Most infected people show no symptoms, but roughly 20 percent experience flu-like illness—fever, headache, muscle aches, sometimes a rash—appearing two to fourteen days after a bite. Less than one percent develop serious illness affecting the brain or spinal cord, though risk increases with age and weakens immune systems.
Ottawa Public Health applies larvicide weekly in city storm sewer catch-basins and treats standing water on city property to suppress mosquito populations. Residents can reduce breeding sites by removing unnecessary standing water—bird baths, toys, flowerpot saucers, pool covers, tires, buckets—anything holding water for seven days or longer.
Protection starts with a Health Canada-approved repellent containing DEET or icaridin on exposed skin. Wear light-coloured, loose-fitting long pants, long sleeves, shoes and socks, especially between dusk and dawn when mosquitoes are most active. Make sure window and door screens fit properly and cover rain barrels with tight-fitting screen mesh.
Where in Ottawa were the positive mosquitoes found, and which neighborhoods should residents prioritize protection?
How many positive pools have been detected at this same time in previous years?
We'll update this story as answers emerge.
The facts
Has West Nile virus been found in Ottawa this year?
Ottawa Public Health confirmed the first positive mosquito pool for West Nile virus in 2026 through routine testing that began in June. No human cases have been reported in Ottawa as of July 26, 2026, though two cases were confirmed elsewhere in Ontario.
What are the symptoms of West Nile virus?
Most infected people have no symptoms. About 20 percent experience flu-like illness including fever, headache, and muscle aches, sometimes with a rash, appearing two to fourteen days after a bite. Less than one percent develop serious illness affecting the brain or spinal cord.
How can residents reduce mosquito breeding around their homes?
Remove standing water from bird baths, toys, flowerpot saucers, pool covers, tires, buckets, and anything else holding water for seven days or longer.
What should people wear to protect against mosquito bites?
Wear light-coloured, loose-fitting long pants, long sleeves, shoes, and socks, especially between dusk and dawn when mosquitoes are most active. Use a Health Canada-approved repellent containing DEET or icaridin on exposed skin.
