Weekly West Nile Virus Update

August 18, 2017

Adult mosquito surveillance conducted during the week of August 6, 2017 detected Culex tarsalis activity in most trapping communities spread across southern Manitoba. Five additional WNV positive mosquito pools were detected, bringing the season total to date to thirty-five (35). WNV positive surveillance indicators have been identified in all four health regions in southern Manitoba. There have been no human or horse cases detected anywhere in Manitoba to date.

Preliminary trapping data for the week of August 13, 2017 shows that Culex tarsalis numbers continue to decrease in all regions.

While Culex tarsalis activity has been low this year, virus circulation continues to be detected. As a result the risk of WNV exposure remains. As we continue through what has historically been the highest risk period for WNV exposure individuals are strongly encouraged to adopt personal protection measures (see below) to minimize their risk of WNV exposure. Note that as the days shorten Culex tarsalis will become active earlier in the evening these measures should be adopted earlier

Manitobans are encouraged to enjoy the warm weather activities and reduce the risk of mosquito bites and exposure to WNV 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.

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 weekly average trap counts of Culex tarsalis mosquitoes, fact sheets, posters and information for municipalities and health-care providers, is available on this website.

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


For WNV health concerns, contact your doctor or call:

Health Links - Info Santé
204-788-8200
(Winnipeg) or toll-free 1-888-315-9257