Contact DCHD

Health Department reports first DuPage mosquitoes with West Nile Virus

Fri July 8, 2011

DUPAGE COUNTY- The DuPage County Health Department announced on Friday that the first positive test for West Nile Virus (WNV) in 2011 was discovered in a mosquito trap located in Lemont, which is in the southern portion of DuPage County.  The mosquitoes that tested positive were collected on July 6 and tested July 7. 

The wet and cool spring that the county experienced this year delayed the development of the mosquitoes that spread the WNV.  The hotter temperatures we are now experiencing are more conducive to the spread of WNV, which explains the positive test discovered in Lemont.

DuPage County residents who want to track West Nile virus in their communities may visit This map of mosquito traps throughout the county will be updated as mosquitoes test positive for WNV.  

No human cases of West Nile virus have been reported in DuPage County in 2011.

The Health Department is collecting freshly-dead birds (such as crows or blue jays) for WNV testing. The birds must not show any signs of decay or trauma and we must be able to pick them up in time to be shipped to the state laboratory by the close of business on Thursdays. To report a dead bird, call (630) 682-7400.

West Nile virus is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird.  Most people with the virus have no clinical symptoms of illness, but some may become ill three to 15 days after the bite of an infected mosquito. 

Only about two people in 10 who are bitten by an infected mosquito will experience any illness. Illness from West Nile is usually mild and includes fever, headache and body aches, but serious illness, such as encephalitis and meningitis, and death are possible. Individuals over the age of 50 have the highest risk of severe disease.

The best way to prevent West Nile disease or any other mosquito-borne illness is to take the following precautions:

  • Avoid being outdoors when mosquitoes are most active, especially between dusk and dawn.
  • When outdoors, wear shoes and socks, long pants and a long-sleeved shirt, and apply insect repellent that includes DEET, picaridin, oil of lemon eucalyptus or IR 3535 according to label instructions.  Consult a physician before using repellents on infants.
  • Make sure doors and windows have tight-fitting screens.  Repair or replace screens that have tears or other openings.  Try to keep doors and windows shut, especially at night.
  • Eliminate all sources of standing water that can support mosquito breeding, including water in bird baths, ponds, flowerpots, wading pools, old tires and any other receptacles.
  • In communities where there are organized mosquito control programs, contact your municipal government to report areas of stagnant water in roadside ditches, flooded yards and similar locations that may produce mosquitoes.

The Health Department does not spray for mosquitoes; mosquito prevention is done by municipalities or mosquito abatement districts.

For more information on the DuPage County Health Department, follow us on Twitter @DuPageHD or become a fan on Facebook.

Please click here to print a copy of this press release:

Health Department reports first DuPage mosquitoes with West Nile Virus

# # #