Mosquitoes test positive in Durham Region for West Nile virus

Whitby, Ontario - Durham Region Health Department has received notification that a batch of adult mosquitoes collected in Ajax have tested positive for West Nile virus (WNV). This is the first mosquito batch in Durham Region to test positive for WNV this season.

The positive batch of mosquitoes was collected from one of the Health Department’s mosquito trap sites located in Ajax. Every week between June and September, the Health Department sets mosquito traps across the region and submits mosquitoes for laboratory testing. 

WNV is a mosquito-borne disease that is spread to humans via the bite of an infected mosquito. Mosquitoes become infected by feeding on the blood of a bird that carries the virus. The disease is not passed from person to person, nor from bird to person. Most people who contract the virus will experience mild illness including fever, headache, body ache, nausea, vomiting, and rash on the chest, stomach or back. More serious symptoms can include muscle weakness, stiff neck, confusion, tremors, numbness, and sudden sensitivity to light. Symptoms usually develop between two and 15 days after being bitten by an infected mosquito.

Although the risk of becoming infected is low, the Health Department recommends that residents take the following precautions to minimize the risk of mosquito bites and the possibility of being infected with WNV:

• Wear shoes, socks and light-coloured clothing—including long sleeve tops and full-length pants when outside—especially at dusk or dawn when mosquitoes are most active.
• Use insect repellent containing DEET or icaridin (picardin) on exposed skin, following Health Canada’s safety tips on using personal insect repellents.
• Remove standing water from your property where mosquitoes can breed.
• Ensure window and door screens are in good repair to prevent mosquitoes from entering your home.

The Health Department helps minimize mosquito populations by treating catch basins within Durham Region and other stagnant water sites with a larvicide to help reduce breeding.

For more information on WNV, please call Durham Health Connection Line at 905-668-2020 or 1-800-841-2729, or visit durham.ca/WestNile.

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