Ongoing risk of exposure to West Nile Virus (WNV) has prompted Manitoba Health to order additional adult mosquito spraying in the region.
The City of Morden is the latest community to be included, plus an approximate three-kilometrer radius extension into the R.M. of Stanley. Meanwhile, another round of spraying has been ordered for the Town of Carman, and a three kilometer radius into the R.M. of Dufferin, for Saturday night (August 8th), weather permitting.
According to a news release issued Thursday afternoon, High temperatures across southern Manitoba have shortened the time required for West Nile virus to develop within infected Culex tarsalis mosquitoes and be transmitted to humans.
Data shows increasing trap counts
Surveillance data from last week showed high numbers of adult Culex tarsalis mosquitoes and evidence of infection with West Nile virus. Mosquito counts in Morden exceeded the threshold for the province to begin adult mosquito control. For the week of July 19th to 25th, Southern Health-Santé Sud had the highest culex tarsalis trap catch of any health region in the province. As of July 31st, there had been 37 positive WNV pooled adult mosquito samples collected in Southern-Santé Sud.
To date, there have been no human cases of West Nile virus confirmed in Manitoba in 2026. There was one case last year, but it was related to travel outside of Canada.
Confirmed dates for spraying in and around Morden are still to be announced.
According to a news release issued Thursday by the Province, approved by Health Canada for use in 2017, DeltaGard 20EW® is classified as a reduced-risk pesticide. When applied using ultra-low volume methods and as per label directions DeltaGard 20EW does not present an unacceptable risk to human or environmental health.