The Manitoba government is issuing a ministerial order under the Environment Act to begin spraying for adult mosquitoes with DeltaGard 20EW because of high numbers of adult Culex tarsalis mosquitoes and evidence of a high rate of mosquito infection with West Nile virus (WNV) in the City of Winkler.

Subject to weather and site conditions, adult mosquito control will take place in the areas of, but not limited to, the City of Winkler plus an approximately three kilometres extended zone around the city. This extended zone includes the communities of Reinfeld, Chortitz and Schanzenfeld.

Adult mosquito control is expected to take place overnight between Friday, Aug. 8 and Saturday, Aug. 9, and overnight between Monday, Aug. 11 and Tuesday, Aug. 12. Fogging will proceed weather conditions permitting (will not occur if the temperature is expected to drop below 13 C, there is excessive wind or precipitation). The treatment times and area map will be available at gov.mb.ca.

Public health officials note that recent warm, humid conditions were ideal for Culex tarsalis mosquitoes that can spread the West Nile virus (WNV). The risk for potential human exposure to WNV at this time is high in the Southern Health-Santé Sud region and is considered very high in Winkler and surrounding area. This risk will likely continue during the historical high-risk period (mid-July to mid-August). At this time, no locally acquired human cases of West Nile virus have been confirmed in Manitoba.

Anyone participating in outdoor activities in and around the City of Winkler, and other areas in southern Manitoba, should take steps to reduce the risk of mosquito bites and potential exposure to the virus. 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.

Approved by Health Canada for use in 2017, DeltaGard 20EWis classified as a reduced-risk pesticide. When applied using ultra-low volume methods and as per label directions, DeltaGard 20EW is unlikely to affect human health.

However, individuals can minimize their exposure by taking the following precautions:

  • staying indoors during and immediately after spraying;
  • closing all doors and windows;
  • avoiding trucks while spraying is underway;
  • turning off fans and air conditioners or setting them at exhaust;
  • removing clothes and children’s toys from outdoor areas;
  • covering swimming pool surfaces;
  • washing any household items or toys left outside before using them; and
  • ensuring homegrown fruits and vegetables are washed before eating.

West Nile Virus is a mosquito-borne virus that can cause severe illness including encephalitis (swelling of the brain) and can sometimes result in long-term complications and death. It only takes a single bite from an infected mosquito to contract WNV. 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 gov.mb.ca.

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