Mosquitoes & West Nile Virus

West Nile virus (WNV) is spread through the bites of infected mosquitoes. It causes an infection called West Nile fever. To prevent the spread of WNV, Public Health:

  • Monitors the numbers, species and locations of mosquito populations in our communities
  • Investigates complaints about standing water on private properties
  • Applies environmentally friendly larvicide to standing water (e.g., storm water ponds, catch basins) to reduce the mosquito population

For more information on getting a catch basin on your property treated, see below.

Lessen your chance of getting bitten by mosquitoes

Eliminate the places mosquitoes breed

Get rid of standing water on your property - for example, by draining flowerpots and kids’ pools and by frequently replacing water in bird baths and other water features

For smaller bodies of standing water on private property, such as fish ponds or swimming pools that remain closed for the summer, you can apply a larvicide called AquaBac™200G to help reduce mosquito populations (get it from Home Hardware stores, item #5047-451)

Report standing water

Public Health investigates complaints about standing water, including ponds and unmaintained swimming pools on private property. Call 1-800-265-7293 ext. 4753 to speak to a public health inspector. If you live in Guelph, call the Property Standards Inspection Department at 519-837-5615 ext. 2526 instead.

Submitting dead birds for testing 

WDGPH no longer collects birds for West Nile virus surveillance, however certain dead birds may be submitted to the Canadian Wildlife Health Cooperative (CWHC) at the Ontario Veterinary College under certain circumstances, and depending on the physical condition of the bird.

  1. CWHC may accept birds of prey and water birds (hawks, owls, eagles, ospreys, herons, loons, etc.).
  2. CWHC may accept songbirds (e.g. robins, finches, chickadees, warblers).
  3. CWHC may accept Corvids (crows, ravens, blue jays).

CWHC assesses each submission request on a case by case basis, so please call ahead to discuss the situation. Casual drop-offs will likely not be accepted. For more information, call the CWHC at 1-866-673-4781 or 519-824-4120 ext. 54662.

How to get a municipally owned catch basin on your property treated

Catch basins are similar to storm sewers. They collect water after rainfalls and when snow melts. This standing water may become a breeding area for mosquitoes.

If you have a catch basin on your property and would like it treated, complete and submit our waiver form as soon as possible in the spring. If your catch basin was treated last summer, you will receive a letter and waiver form for re-treatment ahead of the next summer season.

The product used is called Altosid Briquets XR. For more information about the product, view the label (PDF, 2 pages, 1 MB) or material safety data sheet (PDF, 4 pages, 32 KB).

Typical backyard catch basins look like this:

Catch basin, round hump shaped with holes for water. 

Catch basin, square with long rectangular holes for water

This is not a catch basin:

Plastic round cover