West Nile virus (WNV) is a mosquito-borne virus that first emerged in 1999 and has quickly spread across the country. WNV is not known to be transmitted person-to-person or animal-to-person, but rather by infected mosquitoes when they bite humans or animals.
There are several mosquito species found in Illinois. WNV is predominately transmitted by the Culex mosquito. The Culex mosquito feeds between dusk and dawn and becomes active in late spring/early summer. Adult Culex mosquitoes do not fly far from where they develop as larvae.
There are other species of mosquito that may be active in times other than between dusk and dawn and some of these species are prevalent in the spring, before WNV activity is present. These mosquitoes can be a nuisance and some have been known to carry disease. If you notice mosquitoes between dawn and dusk or before WNV activity is present, the above precautions should be followed. Mosquitoes that are active between dawn and dusk or during the spring do not typically transmit WNV.
The Champaign-Urbana Public Health District (C-UPHD) and the Champaign County Public Health Department (CCPHD) survey mosquito pools and dead birds to detect and monitor the presence of WNV in Champaign County. During the months of May through October, mosquitoes are trapped at various sites and are tested to determine if WNV is present and to what extent. Surveillance also includes collecting and submitting dead birds for testing. Birds that are eligible for testing include crows, blue jays, robins, and other perching birds. The birds must be freshly deceased with no apparent cause of death. From May through October, residents who live in Champaign County who observe an eligible bird should contact the health department immediately to determine if a bird is acceptable for testing. If WNV is detected in mosquito or bird populations, the C-UPHD and the CCPHD work with local units of government and the media to inform and educate the public.
The C-UPHD contracts with the City of Champaign, the City of Urbana, and the Village of Savoy to provide a mosquito abatement program. Larvicides, which disrupt the life cycle of mosquitoes, are applied to all municipal catch basins that hold standing water. These products are specifically designed to prevent adult mosquito emergence and will not adversely affect humans or mammals.
To learn more about WNV and other mosquito-borne diseases, and about prevention methods, or to file a complaint about a mosquito production site, contact us at (217) 373-7900 or (217) 363-3269.