Province orders mosquito spraying for Winnipeg, West St. Paul to ward against West Nile virus

The Manitoba government is ordering the rural municipality of West St. Paul and the City of Winnipeg to fog for mosquitoes as the risk of West Nile virus increases.

Spraying will take place on Thursday evening, pending weather and site conditions

Culex tarsalis, the mosquito known to transmit West Nile virus to people, has yet to emerge in significant numbers. Entomologist Rob Anderson has observed early activity by Culex restuans, which transmits the virus among birds. (Source unknown)

The Manitoba government is ordering the rural municipality of West St. Paul and the City of Winnipeg to fog for mosquitoes 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.

Twenty positive mosquito pools were collected last week in Altona, Beausejour, Boissevain, Brandon, Carman, East St Paul, Morris, Selkirk, Stonewall, West St Paul, Winkler and Winnipeg., a weekly West Nile virus update report issued on Wednesday says

To date, 26 positive mosquito pools have been collected, with the other six reported last week.

The spraying, although subject to weather and site conditions, will take place on Thursday at 10 p.m. in the areas of, but not limited to, the RM of West St. Paul and the City of Winnipeg's insect management areas:

  • 43 - North Inkster Industrial, Oakpoint Highway, Omand's Creek Industrial, Tyndall Park.
  • 44 - Burrows - Keewatin, Inkster Industrial Park, Mynarski, Pacific Industrial, Shaughnessy Park, Weston, Weston Shops.
  • 48 - Inkster Gardens, Mandalay West, The Maples.
  • 49 - Garden City, Leila - McPhillips Triangle, Margaret Park, Templeton – Sinclair.
  • 51 - Amber Trails, Leila North, Riverbend, Rivergrove, Rosser - Old Kildonan, West Kildonan Industrial

Because of the ministerial order, buffer zones will no longer be in effect in Winnipeg, a city release says. 

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

The city is fogging in its insect management areas 43, 44, 48, 49 and 51, and buffer zones won't be in effect. (City of Winnipeg)

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

No human cases have been identified in Manitoba this season, but between 2012 and 2018, there were 112 cases of the virus in Manitoba.

Nearly 40 per cent of these cases were hospitalized and 11 required intensive care.

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 label directions, it is unlikely to affect human health, the release says.

Even so, the province 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.