Manitoba orders mosquito spraying for Ste. Anne, Portage la Prairie to fight West Nile virus

The Manitoba government is ordering fogging for mosquitoes in the town of Ste. Anne and the city of Portage la Prairie, as the risk of West Nile virus increases.

The municipalities must spray for mosquitoes using DeltaGard 20EW because of a high number of adult Culex tarsalis mosquitoes that carry the West Nile virus and evidence of infection, the province said in a news release on Wednesday.

The spraying, subject to weather and site conditions, will take place in the evening and at night, and is expected to begin as early as Thursday evening.

Last week, Manitoba Health detected 36 more West Nile virus-positive Culex tarsalis mosquito pools, in Altona, Boissevain, Brandon, Carman, Niverville, Portage la Prairie, Ste. Anne, Stonewall, West St. Paul and Winnipeg, a weekly West Nile virus update report issued on Wednesday says. 

So far this year, 62 positive mosquito pools have been collected, with the majority in the Winnipeg Health Region, the province said.

There have been no human cases of West Nile virus identified in Manitoba this season and there were none in 2020. Between 2012 and 2018, there were 112 cases in Manitoba. Nearly 40 per cent of those cases were hospitalized and 11 required intensive care, the province said in its news release.

The province ordered spraying in parts of Winnipeg and in the RM of West St. Paul last week.

The hot temperatures and dry conditions this summer have created ideal conditions for mosquitoes that carry West Nile virus, the province says.

The risk for potential human exposure is high, and the province says that will likely continue through a historical high-risk period in August.

Public health officials strongly recommend people reduce their risk of mosquito bites and potential exposure to the virus by:

• Reducing the amount of time spent outdoors during peak mosquito hours between dusk and dawn.
• Using mosquito repellent.
• Wearing light-coloured, loose-fitting clothing with long sleeves and pant legs.
• Maintaining door and window screens so they fit tightly and are free of holes. 
• Preventing standing water around your home.

The province says DeltaGard 20EW is considered a reduced-risk pesticide. When applied using ultra-low volume methods and as per directions, it is unlikely to affect human health, the release says.

You can reduce exposure by taking the following precautions:

• Staying indoors during and immediately after spraying.
• Closing all doors and windows.
• Avoiding spraying trucks while fogging 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.
• Ensuring fruits and vegetables are washed.

Anyone with concerns about West Nile virus should call their health-care provider or Health Links at 204-788-8200 in Winnipeg or toll-free at 1-888-315-9257.