Late July to early August is when the region will face its hottest weather of the year, averaging around 24-27 degrees Celsius, with risks of extreme temperatures of over 30 degrees Celsius.
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.
“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.”
PPH 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, five 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.
Approximately 80 per cent of those infected with West Nile virus are asymptomatic. Of the 20 per cent that do show symptoms, most experience mild illness with symptoms such as:
• Fever
• Headache
• Body aches
• Fatigue
• Skin rash
• Occasionally, vomiting and nausea
However, about 1 per cent 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.
To prevent:
• Always empty standing water on 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.
