Mosquitoes in Mississauga have tested positive for the West Nile virus, marking the first confirmed cases in Peel Region this year.

The virus appeared in two batches of mosquitoes collected this week by Peel Region's Environmental Health department. One batch was collected near Hurontario Street and Burnhamthorpe Road East and the other batch was collected near Dixie Road and Dundas Street East.

"There are positive mosquitoes found every year in Peel, every year since 2001," according to Paul Callanan, Peel Region's director of Environmental Health, adding that this is the time of year when the first positive results start.

There are 31 mosquito traps across Peel Region, and they are sampled on a weekly basis, Callanan told CBC News.

The positive test results add to the five other batches that have tested positive for the virus across Ontario. There have been three in Windsor-Essex, one in Haliburton-Kawartha-Pine Ridge district, and one in Hasting and Prince Edward Counties.

There have been no confirmed human cases of West Nile Virus yet this season, Callanan said, and the risk to humans remains low.

"A lot of people who are exposed to West Nile Virus don't see any symptoms at all," Callanan said. "A fairly low proportion of people have non-specific symptoms and once they're exposed they develop a natural immunity."

Non-specific symptoms include fever, a headache or bodyaches, Callanan said. A rash or swollen lymph nodes may also develop.

Only a small percentage of people who contract the virus will develop the full-blown syndrome, which has far more serious health consequences.

There were only a handful of human cases diagnosed in Peel Region last year, he said.

Still, residents should protect themselves from exposure to mosquitoes by wearing light-coloured, long-sleeved clothing, pants and a hat, using insect repellent and draining standing pools of water — including in pails, wheelbarrows and birdbaths.

Residents should also stay indoors as much as possible at dusk and dawn, when mosquito activity is at its highest.