West Nile Virus detected in mosquito pool near Simms

GREAT FALLS, Mont. - A mosquito pool southeast of Simms has tested positive for West Nile Virus (WNV), the first in Cascade County.

There have been no known human infections of WNV in the county in 2026, the Cascade City-County Health Department reported.

The area where the sample was collected has been treated and is being monitored. 

People are asked to defend themselves against WNV using the 5 “D’s:”

• 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.

Severity and symptoms of WNV can be different, and around 80% of infected people have no symptoms, while up to 20% can develop West Nile fever. 

Fever symptoms can appear 3 to 14 days after exposure and may include a headache, rach, high fever, stiff neck, mental confusion, muscle weakness, tremors, convulsions, coma and paralysis.

CCHD says the fever usually resolves itself with treatment, but dangerous brain infections can develop in 1 in 150 people. Anyone with symptoms is asked to see their healthcare  provider immediately.