McHenry County Department of Health - Environmental Health
Translate this page:

Mosquitoes and West Nile Virus

Press Enter to show all options, press Tab go to next option
  West Nile Virus: mosquito
A Culex pipiens mosquito is the most common mosquito found around the world. This species carries the West Nile virus in Illinois.
In Illinois, West Nile Virus was first identified in 2001.  West Nile Virus in Illinois is primarily associated with the Culex species of mosquito which lay their eggs in warm, stagnant water with high organic content. Eggs are laid on or just above the water surface, where they usually hatch within 2 to 3 days.
The role of the McHenry County Department of Health involves public education and surveillance. The surveillance activities include:
  • Tracking human cases of West Nile Virus in McHenry County
  • Collection/submittal of dead birds for analysis
  • Collection and analysis of Culex mosquitoes for West Nile Virus.
  • Remediation of sites that promote mosquito breeding (i.e. dumps, discarded tires, abandoned pools). 


This web site contains information regarding West Nile Virus, West Nile Virus surveillance activities in McHenry County, educational materials, and information on how to protect yourself and your property from West Nile Virus (WNV).


 Mosquito Life Cycle
 FAQs about WNV
 McHenry County WNV Data
 Protect Yourself and Your Home from WNV
 WNV Educational Materials


Free viewers are required for some of the attached documents.
They can be downloaded by clicking on the icons below.

Acrobat Reader Download Acrobat Reader Flash Player Download Flash Player Windows Media Player Download Windows Media Player Microsoft Silverlight Download Microsoft Silverlight Word Viewer Download Word Viewer Excel Viewer Download Excel Viewer PowerPoint Viewer Download PowerPoint Viewer