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West Nile Virus Has Been Found In Mosquito Pools Across Ontario & Here's How To Stay Safe

Don't forget your insect repellent!

Toronto Staff Writer
Mosquito. Right: Pond in Toronto.

Mosquito. Right: Pond in Toronto.

Several mosquito pools across Ontario have recently tested positive for West Nile virus (WNV) this summer.

Toronto Public Health reports that five pools have tested positive in Etobicoke, North York and west Toronto for the first time this year. However, the risk of being infected with WNV is still low in Toronto, according to a news release on August 8.

Hamilton, Durham Region and Halton Region have also recently reported infected mosquito pools within the last few weeks.

As of August 5, Halton Region reports that a group of mosquitoes captured last week in Oakville have tested positive for the virus.

Durham Region has found two positive pools — one in Oshawa and the other in Clarington — from testing between June 9 to August 4, according to their website.

Meanwhile, Hamilton's risk for WNV moved from low to moderate after a group of mosquitoes tested positive in the week of July 29, according to a news release.


West Nile virus is an infection that people can contract through mosquito bites. It can cause sickness and severe illness in older adults and immunocompromised people, according to TPH.

If you happen to get infected with the virus, symptoms — which can include "fever, headache, nausea, vomiting, body aches, skin rash and swollen lymph glands" — usually develop in 2 to 14 days following the bite.

However, according to the City of Hamilton, "Approximately four-out-of-five people infected with West Nile Virus will have no symptoms."

Meanwhile, the other 20% or so of those infected develop West Nile fever, and only around 1% develop severe illness.

So, while you may feel concerned about recent WNV findings, there is no need to panic.

How to stay safe

To avoid being bitten by mosquitoes, TPH recommends residents wear light-coloured clothing, long-sleeved shirts and long pants when outdoors and apply insect repellent containing DEET or icaridin — especially at the "peak mosquito-biting hours" around dusk and dawn.

Standing water (i.e., any water that collects or pools, including in or on "pool covers, buckets, planters, toys and waste containers") is a breeding ground for mosquitoes, so if you have any on your property, you may want to get rid of it just to be safe.

Another precautionary step is to ensure windows and doors have tightly fitted screens so mosquitoes can't get in.

This article's cover image was used for illustrative purposes only.

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