West Nile Virus
Author: Jessica Bushnell, Mosquito Board
West Nile Virus
Jessica Bushnell
Mosquito Board
West Nile Virus (WNV) is becoming a concern in central Montana. The first cases of the year were reported in Daniels and Sheridan Counties.
WNV typically enters Montana from the eastern border with North Dakota and gradually spreads westward as songbirds migrate throughout the state. The virus was first detected in Montana in 2002 and has been a recurring issue ever since, with significant outbreaks occurring approximately every few years. Currently, there are no West Nile cases in Broadwater County.
In Montana, mosquito control districts begin surveillance operations in June to monitor for the presence of WNV. Broadwater County conducts trapping in both the Townsend and Three Forks mosquito districts. These traps consist of a net, a fan, a battery, and a source of carbon dioxide. In Broadwater County, dry ice is used as the source of CO2. The collected mosquitoes are sorted by species at Carroll College. The two species capable of carrying WNV in Montana are Culex tarsalis and Culex pipiens. Mosquitoes are sorted into pools, which are then tested by the state for the presence of the virus.
When any pool tests positive, residents in the area are notified so they can increase their prevention measures. While horses can receive a booster vaccine against WNV, no vaccine is currently available for humans, making prevention the best strategy. To reduce exposure, it is advisable to avoid being outdoors during dawn and dusk, which are peak feeding times for mosquitoes. Wearing long sleeves and pants and using insect repellent containing DEET are also recommended.
The risk for WNV remains high until October, when temperatures begin to drop. However, Broadwater currently has no reported cases of West Nile Virus.
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PhotoCredit: See captions
Image 1 Caption: Broadwater County Logo (for online view)
Image 2 Caption: West Nile Activity Map
Credit: Montana Department of Health and Human Services
Image 3 Caption: Biogents Mosquito Trap
Image Provided: for education, not brand promotion
