How Whiteside County Health Department tests for West Nile virus
Mosquito traps are generally set up first in the communities with the largest population then moved to new communities when positive pools occur. Mosquito surveillance involves trapping mosquitoes, counting them, identifying the species involved and testing the appropriate species for viruses.

These surveillance methods are used to better identify areas where mosquito control efforts are needed. Detection and control of mosquito breeding sites depends upon integrated efforts among state and county agencies as well as private citizens.

Whiteside County Health Department collects and tests mosquito pools annually beginning in July and through late September.