West Nile virus activity continues to increase in Montana, with five human cases now reported across three counties.West Nile virus reported in 3 counties: West Nile virus activity increases across MontanaMontanas first human ca se of 2026 was reported in Cascade County in August. According to the latest information from the Montana Department of Health and Human Services, two cases have now been reported in Cascade County, two in Richland County and one in Sheridan County.Two of the five cases are classified as neuroinvasive, while the remaining three are classified as non-neuroinvasive. No deaths have been reported.The latest state surveillance map also shows 23 mosquito pools have tested positive for West Nile virus across eight counties. Four of those cases have also been reported in horses.DPHHS says mosquito surveillance serves as an early warning system because the virus is often detected in mosquito pools before seasonal cases are identified in people or horses. West Nile virus is transmitted to people through the bite of an infected mosquito. According to the Montana DPHHS website, about four out of five people infected with the virus may not develop symptoms. Symptoms can include fever, rash, body aches and headaches.Approximately one in 150 infected cases develop neuroinvasive West Nile virus, which can lead to meningitis, encephalitis, long-term disability or death. Anyone who believes they may have West Nile virus should contact a health care provider.Health officials recommend following the 4 Ds to reduce the risk of mosquito bites: Dress: Wear long sleeves, long pants, socks and shoes when mosquitoes are active. Drain: Remove or regularly replace standing water around homes. DEET: Use an insect repellent containing DEET or another EPA-registered ingredient. Dawn and dusk: Limit time outdoors during these periods, when mosquitoes that spread West Nile virus are most likely to bite.The states surveillance map is updated weekly or as new information is collected. Additionally, current case reports are preliminary and could change as additional investigations are completed.For a broader look at West Nile virus activity, the Centers for Disease Control and Prevention tracks cases nationwide. ...read more read less