June 1, 2009
First Mosquitoes Test Positive for West Nile Virus in Northern Illinois
SPRINGFIELD, Ill. – Dr. Damon T. Arnold, state public health director, today announced mosquito samples collected in Cook County have been confirmed as the first positive West Nile virus test results in Illinois this year.
A positive mosquito sample was collected on May 11 in Evanston and on May 11 in Wilmette.
“We expect to see West Nile virus every year in Illinois and these 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 2008, the first positive mosquito samples were reported May 23 in DuPage and Tazewell counties. Last year 28 of the state’s 102 counties were found to have a West Nile positive bird, mosquito, horse or human case. A total of 20 human cases of West Nile disease, including one death, were reported last year in Illinois.
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 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. The first human case in Illinois is not usually reported until July or later.
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.
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:
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.
of Public Health
535 West Jefferson Street
Springfield, Illinois 62761
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