Skip to main content

West Nile Virus

Weekly Vector Index#

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 early September.

Last updated: September 13, 2021. Next scheduled update: Summer 2022

VECTOR INDEX (map of quadrants):

  • NW Quadrant: 0.03   
  • NE Quadrant:  0.00   
  • SE Quadrant:  0.18   
  • SW Quadrant: 0.05

Highest Vector Index value for 5-trap (minimum) Floating Zone: 0.0

Floating Zone description: NA

Map of Mosquito Traps

Map of this week's positive traps


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