A second Positive Pool of Mosquitoes for West Nile Virus Found in Waterloo Region

August 01, 2025

One pool (trap site) of mosquitoes has tested positive this week for West Nile Virus in the City of Cambridge. This brings the total number of positive pools to date in the Region to two so far this year. Although the positive pool of mosquitoes was found in one location in the Region, this is an indicator that West Nile Virus is present throughout the Region. Therefore, it is important for people to take precautions against West Nile Virus throughout the Region. West Nile Virus also has been detected at various locations across Ontario this season with one human case reported to date. There have been no human cases to date in Waterloo Region.

“This is our second positive pool of mosquitoes so far this year and a number of positive pools can be expected over the course of a season. This reinforces that West Nile Virus is here, throughout the Region, and that residents across the Region should take precautions to reduce their risk,” says Dr. Hsiu-Li Wang, Associate Medical Officer of Health.

Public Health urges residents to take the following precautions:

Make personal protection a priority

  • Wear light-colored, tightly woven long-sleeved shirts, pants and a hat.
  • Minimize time spent outdoors during dusk and dawn.
  • Apply a repellant containing DEET. Follow manufacturer’s instructions and never use a concentration higher than needed for the time you plan to spend outdoors. Eucalyptus plant compounds and soybean oil are other alternatives.
  • The use of DEET on a child under the age of six months is not recommended.
  • Make sure that door and window screens fit tightly and have no holes that would allow mosquitoes to enter.

Eliminate mosquito breeding grounds

Eliminate standing water on your property to reduce places where mosquitoes can breed including water in bird baths, eaves troughs, and flower pot saucers.

  • Don’t allow outdoor objects to collect water.
  • Cover rain barrels with a fine mesh screen.
  • Change water in birdbaths and livestock watering tanks at least once a week.
  • Don’t allow water to collect in roadside ditches or in low lying areas on your property.
  • Clean up brush and debris that could act as mosquito breeding areas.

For more information about West Nile Virus, call 519-883-2008 ext 5147 or visit: http://chd.region.waterloo.on.ca/en/healthylivinghealthprotection/westnilevirus.asp

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Media contact:

Candace Harrington
Coordinator of Marketing and Communications
519-883-2244 or CaHarrington@regionofwaterloo.ca