mosquito about to bite 

Mosquito Control

Due to the increased rainfall and flooding, residents should continue to practice the 4Ds to protect themselves from the risk of West Nile virus (WNV). Low levels of WNV activity in Colorado commonly continue through September and into October.

West Nile Virus

Mosquitoes can be bothersome pests, but they can also carry diseases like West Nile virus. Learn what you can do to protect yourself and your family and find out what Boulder County is doing as well.

What You Can Do

What Boulder County is Doing

West Nile Virus

Vector Index Log

The vector index tell us the relative risk of West Nile virus transmission. The vector index is based on the:

  • Total number of Culex Pipien and Culex Tarsalis – the species that carry West Nile virus
  • Number of infected mosquitoes across an area

We calculate the vector index by determining the average number of infected mosquitoes collected per trap in an area. Emergency spraying may be recommended when the vector index is at 0.75 or higher.

Zone 1 Zone 2 Zone 3
Season Week Vector Index Vector Index Vector Index
May 19 - 25 0.00 0.00 0.00
May 26 - June 1 0.00 0.00 0.00
June 2 - 8 0.00 0.00 0.00
June 9 – 15 0.00 0.00 0.00
June 16 – 22 0.00 --- 0.00
June 23 – 29 0.11 --- 0.00
June 30 – July 6 0.15 0.49 0.08
July 7 – July 13 0.19 1.32 0.27
July 14 – July 20 0.18 1.18 0.00
July 21 – July 27 0.17 0.32 1.07
July 28 - August 3 0.47 0.20 0.00
August 4-10 0.00 3.22 0.00
August 11-17 0.43 2.01 0.18
August 18-24 0.00 0.44 0.00
August 25-30 Pending 0.44 0.00
September 1-7 --- 0.72 ---

NOTE: "---" indicates a single pool was submitted for that zone that tested positive, therefore we were unable to calculate an infection rate or vector index for that zone.

Sentinel Map

sentinel map for mosquito monitoring

 Related Links

Animal-Borne Diseases

Contacts

Vector Control Program

303-441-1564
Submit a question

www.BoulderCountyVector.org

Boulder

3450 Broadway
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