Dr. Jeff Powis, Infectious Diseases Specialist and Medical Director at Michael Garron Hospital
Dr. Jeff Powis, Infectious Diseases Physician and Medical Director, Infection Prevention and Control, Michael Garron Hospital

Ask the Expert: Dr. Jeff Powis 5 Ways to Prevent West Nile Virus

It might begin as a tingling sensation on your skin on a hot summer night – but before long, this is replaced by itchy bumps, swollen skin and excessive scratching.

The mosquito strikes again.

This year, a relatively mild winter and an especially wet spring and summer has cultivated the perfect breeding ground and weather conditions for mosquitoes – and with it, the perfect storm for West Nile virus in Toronto and southern Ontario to thrive.

West Nile cases typically begin to surface in late August, early September as it takes a while for mosquitoes to become infected. Most people get West Nile after being bitten by an infected mosquito – and mosquitoes become diseased when they feed on infected birds. These mosquitoes can then spread the virus to humans and other animals.

Five ways to protect yourself against West Nile virus

Whether you’re spending the long weekend in the city or travelling north to the cottage, it’s important to take the proper precautions to protect yourself and family from West Nile Virus.

MGH News interviewed Dr. Jeff Powis, Infectious Diseases Specialist and Medical Director, Infection Prevention and Control & Antimicrobial Stewardship at Michael Garron Hospital on the topic. Here’s what he had to say:

  1. Avoid being outdoors during mosquito peak hours: “Mosquitoes transmitting West Nile like to bite in the morning and at dawn and dusk. I would try and avoid these times, or if you’re going to be outside longer, use extra precautions.”
  2. Wear protective clothing: “As we head into September, the evenings are cool enough that you can get away with wearing longer sleeves, pants and socks.”
  3. Use insect repellent containing DEET“This is the most effective mosquito repellent based on infectious diseases literature. Studies have shown that DEET sees the most reduction in bites.
  4. Remove standing water: “Mosquitoes like to have babies in standing water so be sure to reduce standing water sites around your home, for example flower pots, furniture covers or draining puddles of water under the deck.”
  5. Be active! “I always tell my son not to stand still. It’s better for your health to be active than to avoid going outdoors. If you stand still or sit down you're more likely to be bitten!”

Individuals infected with West Nile typically show symptoms between two and 15 days after being bitten. Symptoms may include headache, fever, aches and pains – and on rarer occasions, individuals might experience a rash or eye inflammation. If you experience this combination of symptoms, visit your family doctor or a primary care physician in the community, who will conduct a blood test.

The vast majority of mosquitoes do not carry West Nile,” says Dr. Powis, also an Associate Professor at the University of Toronto.

“Be careful during peak times and follow preventative precautions to enjoying the remaining weeks of summer.”

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