Hotter Temperatures May Increase Risk of West Nile Virus
Written by Comms Team, July 20, 2022
Residents urged to take precautions with hot weather in the forecast
With warmer weather upon us, we can expect an increase in the local mosquito population. Late July to early August is when the region will face its hottest weather of the year, averaging around 24-27oC, with risks of extreme temperatures of over 30oC. According to Public Health Ontario, warmer weather leads to more mosquitoes that can acquire West Nile Virus, increasing the chance of human exposure to the virus. Now that we have come to the hottest time of year, we should all be extra diligent in protecting ourselves.
“Research shows that when temperatures are warmer throughout the year, there is a higher frequency of mosquito pools that are positive for West Nile Virus,” said Joshua Laite, Student, Vector Borne Disease Program. “When venturing into an area with a lot of mosquitoes, keep your skin covered up as much as possible to prevent bites.”
Peterborough Public Health staff trap mosquitoes throughout the city and county from early June to late September. Since the start of trapping this year, staff have collected more than 6,000 mosquitoes for testing. To-date, no mosquito pools have tested positive for West Nile Virus. Public Health Ontario reports that in 2021 there were 105 positive mosquito pools and 23 confirmed or probable human cases of West Nile virus in Ontario. Locally, 5 human cases of West Nile virus have been reported since 2012, with the most recent case being reported in 2020. Neighbouring regions including Haliburton, Kawartha, Pine Ridge District Health Unit and Hastings Prince Edward Public Health have also reported cases in 2019 and 2020.
How do you protect yourself?
Clean up:
- Always empty standing water on your property to remove the habitat where mosquitoes lay their eggs. This includes flower pots, wheel barrows, pool covers, old tires, garbage/recycling cans and other places that might inadvertently create a puddle or body of still water.
- Fill in low depressions in your lawn to prevent puddles.
- Change water in bird baths at least once a week.
- Clean out dense bushes and shrubs where mosquitoes can rest.
- Turn over compost piles on a regular basis.
- Ensure that window and door screens fit tightly and do not have holes.
Cover up:
- Stay indoors at dusk and dawn because mosquitoes are most active during these times.
- Use a bug repellent containing DEET, following the manufacturer’s instructions.
- Cover up with light coloured, long clothing. This includes long-sleeved shirts, long pants, and socks. Also, wear footwear that covers exposed skin.
What are the symptoms of West Nile virus?
Approximately 80% of those infected with West Nile virus are asymptomatic (i.e. do not show any symptoms). Of the 20% that do, most experience mild illness with symptoms such as:
- Fever
- Headache
- Body aches
- Fatigue
- Skin rash
- Occasionally, vomiting and nausea
However, about 1% of those infected with West Nile virus may experience severe illness involving the central nervous system. In its most serious state, West Nile virus infection can cause an inflammation in the brain, otherwise known as encephalitis.
For more information on mosquitoes and West Nile virus please contact the Vector Borne Disease Program at Peterborough Public Health at 705-743-1000, ext. 152 or visit our website at www.peterboroughpublichealth.ca/your-health/insects-rodents-other-pests/west-nile-virus/
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For further information, please contact:
Sarah Gill
A/ Communications Manager
705-743-1000 ext. 352