The first Culex tarsalis mosquitoes infected with West Nile Virus this year have shown up in Manitoba.

The samples were found in traps Oakbank, just northeast of Winnipeg, during the week of July 20, according to a press release from the province.

At this time, no human cases of West Nile Virus have been identified in Manitoba, the province said, noting the bulk of mosquitoes collected in the traps continue to be nuisance mosquitoes, which do not transmit WNV.

However, the potential for human exposure to infected Culex tarsalis mosquitoes is present throughout southern Manitoba, where the number of Culex tarsalis — the only type of mosquito that contracts and transmits the potentially lethal virus — has been detected.

And the risk of exposure to WNV is expected to continue in the coming weeks, particularly if warm and dry conditions persist, as these are ideal for Culex tarsalis development and activity, the province said.

People can reduce the risk of mosquito bites and exposure to West Nile Virus by:

  • Reducing the amount of time spent outdoors during peak mosquito hours: between dusk and dawn.
  • Using appropriate mosquito repellent.
  • Wearing light-coloured, loose-fitting clothing.
  • Maintaining door and window screens so they fit tightly and are free of holes.

People can reduce the number of mosquitoes around their homes by eliminating standing water.

  • Clean eavestroughs and regularly empty bird baths, old tires and other items that collect water.
  • Ensure rain barrels are covered with mosquito screening or are tightly sealed around the downspout.
  • Improve landscaping to prevent standing water around the home.

More information about West Nile Virus, including weekly average trap counts of Culex tarsalis mosquitoes, fact sheets, posters and information for municipalities and health-care providers, is available on the government website. A link is at left of this page.