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West Nile Virus

Weekly Vector Index#

Recommendations to spray for adult mosquitoes are made by the Larimer County Health Department, and are based on data from at least a 5-trap area that has a vector index of 0.75 or higher. The City operates a network of 53 traps providing weekly data on the level of WNV in targeted areas.

WNV vector index levels updated weekly, June 15 through September 20.

Last updated: September 20, 2022. Next scheduled update: Summer 2023

VECTOR INDEX (map of quadrants):

Highest Vector Index value for 5-trap (minimum) Floating Zone: 0.41

Floating Zone description: NE quadrant, I-25 between East Vine and Mountain Vista, to College Ave. 

Map of Mosquito Traps

  • NW Quadrant: 0.00   
  • NE Quadrant:  0.37 
  • SE Quadrant:  0.06   
  • SW Quadrant: 0.00


Most recent three weeks' trap data:

Interactive Mosquito Surveillance & Control Map#

Mosquito surveillance and control sample map

Our mosquito control contractor, Vector Disease Control International, has interactive mosquito surveillance and control maps you can review.

View Map