News Releases

Media Bulletin - Manitoba

July 15, 2021


Manitoba Health and Seniors Care reports the hot temperatures and dry conditions experienced this summer have created ideal conditions for Culex tarsalis, mosquitoes that carry the West Nile virus (WNV).

However, the drought has dried up many sites where mosquitoes would normally lay their eggs. This has left mosquitoes searching for water to lay their eggs and for their larvae to develop. Some are now finding this scarce resource in unusual locations, such as smaller rivers and creeks.

While normally not suitable, the drought has caused some smaller rivers and creeks to stop flowing thus creating ideal spots for Culex tarsalis to lay their eggs. As a result, larval control will be conducted along these unusual larval development sites, to reduce the numbers of Culex tarsalis adults that emerge and reduce the risk of WNV.

Subject to weather and site conditions, the City of Winnipeg will conduct larval control in the areas of, but not limited to, the Seine River, Omand’s Creek and Sturgeon Creek later this week.

Although the risk for potential human exposure to WNV is low at present, it is likely to increase, particularly as the province proceeds through the historical high-risk period for human exposures in July and August.

At this time, no human cases of West Nile virus have been identified in Manitoba.

While Manitobans are encouraged to enjoy warm weather outdoor activities, it is strongly recommended they reduce their risk of mosquito bites and potential exposure to WNV. Key prevention measures include:
• reducing the amount of time spent outdoors during peak mosquito hours between dusk and dawn;
• using an appropriate mosquito repellent;
• wearing light-colored, loose-fitting clothing with long sleeves and pant legs;
• maintaining door and window screens; and
• cleaning and emptying yard items that collect water.

Protecting yourself against WNV helps protect the health-care system, which continues to see strain due to COVID-19. Between 2012 and 2018, there were 112 cases of WNV in Manitoba. Nearly 40 per cent of these cases were hospitalized and 11 required intensive care.

Information on the risk of West Nile virus will continue to be provided to the public throughout the summer. Manitobans can also check the WNV website regularly for up-to-date data and information.

More information about West Nile virus, including prevention, symptoms, weekly average trap counts of Culex tarsalis mosquitoes, fact sheets, posters and information for municipalities and health-care providers, is available at

Manitobans can also contact Health Links–Info Santé at 204-788-8200 or at 1-888-315-9257 (toll-free) for more information.

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