Peel Public Health confirms first West Nile virus positive mosquitoes for 2025

BRAMPTON, Ont. - July 22, 2025. The season's first West Nile virus positive mosquitoes have been identified in Peel region. The mosquitoes were collected from a trap in Mississauga near the intersection of Airport Road and Derry Road East.

West Nile virus is a mosquito-borne disease passed to humans from the bite of an infected mosquito. In rare cases, the virus can cause serious illness—such as swelling of the brain (encephalitis) or spinal cord (meningitis). Older adults, people with weakened immune systems, and those with certain chronic health conditions are at higher risk for serious complications. Peel Public Health has not confirmed any human cases of West Nile virus to date this year.

Peel Public Health reminds residents there are simple things you can do to protect against mosquito bites:

• Apply a Health Canada-approved insect repellent containing an ingredient effective against mosquitoes, such as DEET or icaridin, to exposed skin and clothing. Always follow the manufacturer’s instructions. For additional information on choosing an insect repellent, please refer to: https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html

NOTE: Infants younger than 6 months old should not use an insect repellent containing DEET or icaridin. Instead, use a mosquito net when babies are outdoors in a crib or stroller.

• Wear light-coloured, tightly woven, loose-fitting clothing, such as long pants, a long-sleeved shirt, shoes, and socks, to protect exposed skin.
• Avoid wooded areas with high mosquito populations and take extra precautions during dusk and dawn, when mosquitoes are most active.
• Ensure all windows and door screens fit securely and are free of tears and holes.

Peel Public Health monitors West Nile virus activity through 33 mosquito traps across Mississauga, Brampton and Caledon. Mosquitoes from the traps are collected and tested weekly from mid-June to September. Peel Public Health also helps minimize mosquito populations by treating regional catch basins and other stagnant water sites with a larvicide to help reduce breeding.

Peel residents can also help prevent mosquito bites by removing or draining items on their property that hold stagnant water. Water that is stagnant for more than 7 days is an ideal breeding site for mosquitoes. Report stagnant water sites to Peel Public Health at 905-799-7700 (or toll-free at 1-888-919-7800) or online. Residents can visit https://peelregion.ca/health/protecting/bugs/ for information about West Nile Virus or to register to receive email notifications about mosquito activity in Peel Region.