First Mosquitoes Test Positive for
West Nile Virus in Illinois
SPRINGFIELD, Ill. – Dr. Damon T. Arnold, state public health director, today announced mosquito samples collected in Gallatin County have been confirmed as the first positive West Nile virus test results in Illinois this year.
The Egyptian Health Department collected the positive mosquito sample on June 3 in Shawneetown. This is the first positive mosquito batch found in the state so far this year. Birds have tested positive for West Nile virus this year in Carroll, St. Clair, Greene, Rock Island, Jo Daviess, Stephenson and Tazewell counties.
“We expect to see West Nile virus every year in Illinois and these first positive West Nile virus samples should remind us that we need to protect ourselves against mosquito bites,” said Dr. Arnold. “I urge everyone to get rid of any stagnant water around their homes to reduce the number of mosquitoes, and to make sure you wear insect repellent to protect yourself.”
In 2009, the first positive mosquito samples were reported June 1 in Cook County. Last year, 36 of the state’s 102 counties were found to have a West Nile positive bird, mosquito, horse or human case. A total of five human cases of West Nile disease were reported in Illinois last year, the first reported on August 31. In hotter summers, such as 2005 and 2006, more human cases have been reported:
- 2008 – 20
- 2007 – 101
- 2006 – 215
- 2005 – 252
- 2004 – 60
- 2003 - 54
Surveillance for West Nile virus in Illinois began on May 1 and includes laboratory tests on mosquitoes, dead crows, blue jays, robins and other perching birds as well as the testing of sick horses and humans with West Nile-like disease symptoms. Citizens who observe a sick or dying crow, blue jay, robin or other perching bird should contact their local health department, which will determine if the bird will be picked up for testing.
West Nile virus is transmitted through the bite of a mosquito that has been infected with 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, 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.
- 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.
Public health officials believe that a hot summer could increase mosquito activity and the risk of disease from West Nile virus.
Additional information about West Nile virus can be found on the Illinois Department of Public Health’s Web site at www.idph.state.il.us/envhealth/wnv.htm.