Hot, dry weather in Manitoba creating ideal conditions for mosquitoes carrying West Nile


The Manitoba government is warning residents that the hot weather and dry conditions the province is currently experiencing has created ideal conditions for Culex tarsalis, the mosquitoes that carry West Nile virus.

In a news bulletin released on Thursday, the province notes that a drought has dried up a number of sites where mosquitoes would typically lay their eggs, which has left the insects looking for water to lay their eggs and develop their larvae. This has caused the mosquitoes to find this resource in unusual locations, such as small rivers and creeks.

According to the province, the drought has also caused smaller rivers and creeks to stop flowing, which creates an ideal location for the Culex tarsalis to lay their eggs. Manitoba notes that typically smaller rivers and creeks would not be suitable for this type of activity.

As a result of these conditions, Manitoba will be providing larval control at these sites in order to reduce the number of Culex tarsalis adults, and consequently reduce the risk of West Nile virus.

The City of Winnipeg will also be providing larval control in certain locations, including but not limited to, the Seine River, Omand’s Creek and Sturgeon Creek. This will take place later this week subject to weather and site conditions.

Manitoba notes that the possibility of human exposure to West Nile virus is currently low, but it is likely to increase, particularly throughout July and August. Currently, no human cases of West Nile virus have been reported in Manitoba this year.

The province provides the following tips for Manitobans to reduce their risk of mosquito bites and exposure to West Nile virus:

Reduce the amount of time you spend outdoors during peak mosquito hours, which are between dusk and dawn;

  • Use a mosquito repellent;
  • Wear light-coloured, loose-fitting clothes with long sleeves and pant legs;
  • Use door and window screens; and
  • Clean and empty yard items that collect water.

Between 2012 and 2018, there were 112 cases of West Nile virus in Manitoba. According to the province, nearly 40 per cent of these cases were hospitalized and 11 needed intensive care.

More information on West Nile virus can be found online.