Mosquito Season

The Cascade County Weed & Mosquito Division has detected its first West Nile Virus (WNV) positive mosquito sample this year. A WNV positive sample of adult Culex tarsalis mosquitos was collected approximately 6 miles North of Great Falls on July 12th, 2018. The sample was confirmed to be West Nile Virus positive by the lab at the Montana Department of Public Health and Human Services (DPHHS) in Helena on July 16th, 2018.

There has been no known infection in humans detected in Cascade County so far this year, but since a WNV positive mosquito sample has been detected, residents are greatly encouraged to take steps to protect themselves.

The severity and symptoms of WNV can vary widely. Approximately 80% of persons infected experience no symptoms, but up to 20% of persons can develop a mild illness, called West Nile fever. Fever generally resolves itself without treatment, but dangerous brain infections such as encephalitis or meningitis can develop in 1 out of 150 people. Symptoms of these diseases might include headache, rash, high fever, stiff neck, mental confusion, muscle weakness, tremors, convulsions, coma, and paralysis. Individuals who develop any of these symptoms should see their healthcare provider immediately.

The single best defense against WNV is bite prevention. To protect yourself, use the 5 Ds:

  • DEET-Apply repellent containing an EPA-registered active ingredient, such as DEET, and follow the directions on the package.
  • DUSK and DAWN-This is when mosquitoes are most active. Try to avoid outdoor activities during these times.
  • DRAIN STANDING WATER-Standing water is the perfect breeding ground for mosquitoes. Drain such areas around your home (gutters, pools, tires, buckets, water bowls, etc.).
  • DRESS APPROPRIATELY-Wear long-sleeved shirts, long pants, and socks.

In June County Commissioners approved increasing the Mosquito Control Fund by $45,000 for additional chemical needed to treat mosquitoes in our area after heavy rains and flooding. Although there will be more mosquito treatment this year Superintendent for the Weed & Mosquito Division, Joshua Blystone, says residents will most likely still see an increase of mosquitoes this season.

West Nile Virus Fact Sheet