Mosquitoes in Hamilton test positive for West Nile virus for the 1st time this year

CBC

26-07-2025

While most who contract the virus have no symptoms, one per cent experience brain swelling
Mosquitoes in Hamilton have tested positive for West Nile virus for the first time this year, leading the city to increase the risk of contracting the virus from "low" to "moderate."
The city trapped a batch of mosquitoes this week that tested positive, it said in a news release issued Friday.
"Residents are reminded to protect themselves against mosquito bites and to remove standing water from private property to prevent mosquito breeding," it says, noting it recommends removing any standing water at least once weekly.
For their part, city workers apply larvicide in municipal street catch-basins, also known as storm drains, as part of an ongoing effort to prevent illness, and have completed two such rounds of treatment this year, said the release.
The city said most people infected with West Nile virus are asymptomatic, but about 20 per cent – including older adults or people with weakened immune systems – can experience West Nile fever.
About one per cent of those who contract the virus experience inflammation of the brain or the lining of the brain, the city said. Symptoms typically appear two days to two weeks after being infected.
The city also recommends wearing mosquito repellant containing DEET or Icaridin, avoiding areas with lots of mosquitoes and wearing long sleeves and pants in places where the insects are present.