Follow the 5 D’s to prevent West Nile Virus in Montana


First West Nile Virus Positive Mosquito Pool Detected in Cascade County

The Cascade County Weed & Mosquito Division has detected three West Nile Virus (WNV) positive mosquito pools in 2017. A WNV positive sample was collected in the Gerber area, in the Vaughn area, and near Benton Lake National Wildlife Refuge.

Joshua Blystone, Superintendent for the Division reassures residents, “The Cascade County Weed & Mosquito Division will continue to collect and test mosquito samples from its surveillance traps through September to ensure we are taking all possible steps to help protect residents from WNV.”  No known infection in humans has been detected in Cascade County so far this year, but residents are still 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.  West Nile 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.


For more information, visit the CCHD website at or the DPHHS website at