Weekly West Nile Virus Update


August 7, 2020

Adult mosquito surveillance conducted during the week of July 26-August 1, 2020 detected Culex tarsalis activity in all of the twenty-one (21) sentinel communities. No WNV infected mosquito pools were detected. A total of zero (0) WNV positive mosquito pools have been collected this season. Surveillance has not detected any additional positive WNV surveillance indicators (e.g. human cases, birds or horses) anywhere in the province. There are currently no orders for adult mosquito control related to West Nile virus.

Mosquito activity for Culex tarsalis has peaked for the season. While mosquito activity is starting to wane, it is important to remember that warm temperatures, in particular in the evening are conducive to Culex tarsalis activity

Soil moisture levels and standing water vary considerably throughout the central and southern portions of the province. Culex tarsalis tends to be more common when conditions are hot and dry as they use small water pools, such as cattle watering troughs, bird baths, and other containers to lay their eggs. Nuisance mosquitoes, which do not carry West Nile can be persistent biters of people and pets and are more common in wet conditions where large puddles and water-filled ditches provide ample habitat for egg laying and larval development.

While the risk of West Nile virus is low, Manitobans should still consider taking appropriate precautions to reduce their risk of mosquito bites and WNV exposure.

Protective measures include:

  • 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.

For WNV health concerns, contact your doctor or call:

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