Evidence of West Nile Virus (WNV) in northern Illinois has surfaced early this year and should serve as a reminder to residents that now is a good time to inspect their homes and yards for sources of standing water. Mosquitoes gathered recently in traps in Cook and DuPage counties have tested positive for the disease, the first reported in the state this year.

The mosquitoes typically seen in late spring and early summer are not the kind that spreads WNV. Those mosquitoes are called “nuisance” or floodwater mosquitoes. West Nile Virus is most commonly associated with the Culex mosquito. Hot, dry weather and stagnant water are the main ingredients prized by the Culex.
“Our neighbors have already seen evidence of West Nile this year, likely to due to the warm weather conditions,” said Health Department Executive Director Paul Kuehnert. “We usually begin to see our first human cases in July or August. With this early arrival, it more important than ever to check your homes and yards now for any places that could collect water and serve as a breeding ground for the Culex.”
The Health Department does monitor for WNV activity in your area. You can visit our Web site at http://kanehealth.com/wnv_surveillance.htm to view a map of the trap locations throughout the county. The Health Department is also collecting dead birds to be sent to the state lab for testing. Please call (630) 444-3040 to report the presence of freshly-dead birds (such as crows or blue jays) for WNV testing. The birds must not show any signs of decay or trauma.
There has been no WNV activity so far this year in Kane County. 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. In 2007 there were 13, four in 2006, 17 in 2005, two in 2004, none in 2003 and nine in 2002.
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 persons 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 and meningitis, and death are possible. Persons 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 includes DEET, picaridin or oil of lemon eucalyptus 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.
• 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 Web site at www.kanehealth.com/west_nile.htm, the Illinois Department of Public Health’s Web site at www.idph.state.il.us/envhealth/wnv.htm. People also can call the IDPH West Nile Virus Hotline at (866) 369-9710 Monday through Friday from 8 a.m. to 5 p.m.