Weekly West Nile Virus Update

 

The WNV Story Map may not always be updated at the same time as the WNV Surveillance Statistics website and the Weekly Update. Please check back later if the Story Map does not align with the Weekly Surveillance Statistics and Weekly Update.

August 14, 2026

Manitoba Health, Seniors and Long-Term Care is reporting the first three human West Nile virus cases of the season. These include:

  • One confirmed case from the Prairie Mountain region
  • Two probable cases from the Interlake-Eastern region

Over the past week, adult mosquito control activities were completed in multiple communities in accordance with previously issued ministerial health orders under the Environment Act, due to high numbers of adult Culex tarsalis mosquitoes and evidence of mosquito infection with West Nile virus (WNV) in the communities. Mosquito control was completed in Boissevain-Morton, Carman, Morden, Stonewall, West St. Paul, Winkler and portions of Winnipeg.

Further details may be found in the news bulletins:

The completed schedule of adult mosquito control is available at: Adult Mosquito Control Schedule | Health | Province of Manitoba.

Adult mosquito surveillance during the week of August 2 to 8, 2026 (week 31) detected C. tarsalis mosquitoes in all 21 trapping communities in Manitoba. The average number of C. tarsalis per trap decreased compared to the previous week for Interlake-Eastern, Prairie Mountain and Winnipeg health regions but increased in the Southern health region. The provincial average remained significantly higher than the historical average for week 31. More details are available at: Surveillance Data for West Nile virus in Manitoba | Health | Province of Manitoba.

89 West Nile virus (WNV)-positive C. tarsalis mosquito pools were detected in Week 31 including in Prairie Mountain Health (Brandon and Killarney), Interlake-Eastern Health (Oakbank, Selkirk and Stonewall), Southern Health/Santé Sud (Altona, Carman, Headingley, Morden, Morris, Portage la Prairie, Ste. Anne and Winkler) and Winnipeg Health regions (Winnipeg and West St. Paul). 14 WNV-positive wild birds (Portage la Prairie-1, East St. Paul-1, Winnipeg-12) were also reported this week; most of them were collected in late July. To date, 273 WNV-positive C. tarsalis pools, 22 WNV-positive birds and zero WNV-positive horses have been identified.

As of August 13, the risk of human exposure to WNV in Manitoba is high. Weather conditions over the next week will likely support ongoing Culex tarsalis activity. Mid-July to mid-August is historically the highest risk period for WNV.


Manitobans are strongly encouraged to reduce the risk of mosquito bites while enjoying outdoor activities 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 with long sleeves and pant legs, and
  • maintaining door and window screens so they fit tightly and are free of holes.

Manitobans can also reduce the number of mosquitoes around their home by eliminating standing water. To reduce standing water:

  • clean eaves troughs and regularly empty bird baths and other items that might collect water,
  • ensure rain barrels are covered with mosquito screening or are tightly sealed around the downspout,
  • clear yards of old tires or other items that collect water, and
  • improve landscaping to prevent standing water around the home.