Manitoba orders fogging in several communities as West Nile

Manitoba orders fogging in several communities as West Nile-carrying mosquito count soars

Buffer zones not allowed in Winnipeg during this fogging program, city says

A high count of the mosquito that carries West Nile virus has prompted a province-mandated fogging program in several areas of Manitoba, including parts of Winnipeg and rural communities.

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, the province said in a news release.

Manitoba is currently in the highest-risk period for human exposure, which occurs between July 15 and Aug. 15 each year, the province said.

Weekly average trap counts of Culex tarsalis are available on the province's West Nile virus website. Surveillance data shows high numbers of adult Culex tarsalis mosquitoes and evidence of infection with West Nile virus, the release states.

The following areas have been targeted for fogging:

The fogging schedule for those communities is available on the Manitoba Health website.

For Winnipeg, the following insect management areas will be fogged between 9:30 p.m. to 6:30 a.m., starting on Friday, according to a news release from the city.

The areas to be fogged on any given night will be announced to the public at least eight hours in advance. Winnipeggers can register online for notifications and receive an automated phone or email alert.

The Manitoba government issued the fogging order under the Environment Act, which requires municipalities to fog when the risk of West Nile virus transmission via Culex tarsalis mosquitoes is high.

A single bite from an infected mosquito can transmit West Nile virus to humans. Infection can cause severe illness resulting in encephalitis (swelling of the brain), long-term complications and death, according to the province.

There has not yet been a human case of West Nile virus this year in the province.

Fogging will be carried out using DeltaGard 20EW, which is classified as a reduced-risk pesticide by Health Canada, the province says. When applied using "ultra-low volume methods" and according to label directions, it is "unlikely to affect human health," according to the provincial news release.

Buffer zones, which allow Winnipeg homeowners to exempt their residence from fogging, are not allowed when it comes to targeting the Culex tarsalis species, the city said in a news release. They only apply when the city fogs for regular nuisance mosquitoes.

Darren Bernhardt has been with CBC Manitoba since 2009 and specializes in offbeat and local history stories. He is the author of two bestselling books: The Lesser Known: A History of Oddities from the Heart of the Continent, and Prairie Oddities: Punkinhead, Peculiar Gravity and More Lesser Known Histories.