More mosquitoes test positive for West Nile Virus

By on July 20, 2012

KANE COUNTY—Three more batches (or pools) of mosquitoes collected recently have tested positive for West Nile Virus. The mosquito batches were collected in Kane County Health Department traps in Aurora, Montgomery and Carpentersville, Ill. This brings the total to five positive batches this year; the second from Carpentersville. These positive mosquito batches usually are the first indicators of West Nile activity.

With this year’s hot, dry weather, these results come as no surprise. First evidence of West Nile typically begins in July or August. And although it has been extraordinarily dry, the few intermittent showers experienced in the area are enough to leave small pools of stagnant water where the Culex mosquito, the species associated with the disease, can breed. Now is a good time to inspect your yard for areas that can collect water and remove it.

The Health Department monitors for WNV activity in your area. You can visit to view a map of the trap locations throughout the county. Also as part of its West Nile program, the Health Department is collecting dead birds to be sent to the state lab for testing. Call (630) 444-3040 to report the presence of freshly-dead birds (such as crows or blue jays) to determine if WNV testing is recommended. The birds must not show any signs of decay or trauma.

In 2011, Kane reported one human case and five cases in 2010. In 2009, an unusually mild summer with cool temperatures, there were no human cases of West Nile Virus reported in Kane County. There were three cases of the virus reported in 2008, 13 in 2007, four in 2006, 17 in 2005, two in 2004, none in 2003 and nine in 2002. You can view more detailed monitoring results from previous years by visiting

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-14 days after the bite of an infected mosquito. Only about two people out of 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, meningitis and death, are possible. People older than 50 years of age have the highest risk of severe disease.

The best way to prevent West Nile disease or any other mosquito-borne illness is to reduce the number of mosquitoes around your home and to take personal precautions to avoid mosquito bites. Precautions include:

Avoid being outdoors when mosquitoes are most active, especially between dusk and dawn. Use prevention methods whenever mosquitoes are present.

When outdoors, wear shoes and socks, long pants and a long-sleeved shirt, and apply insect repellent that, according to label instructions, includes DEET, picaridin or oil of lemon eucalyptus. 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.

Change water in birdbaths weekly. Properly maintain wading pools and stock ornamental ponds with fish. Cover rain barrels with 16-mesh wire screen. 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.

Additional information about West Nile virus can be found on the Kane County Health Department’s website, nile.htm, or the Illinois Department of Public Health’s Web site, envhealth/wnv.htm. People also can call the IDPH West Nile Virus Hotline at 1-866-369-9710, Monday through Friday from 8 a.m. to 5 p.m.