September 19, 2001

SPRINGFIELD, IL – The Illinois Department of Public Health today reported three more dead crows collected in the Chicago area have preliminarily tested positive for the West Nile virus, bringing to 54 the number of birds that have either been confirmed or are possible positives since the virus was first detected in the state two weeks ago.

No human cases of West Nile disease have been reported.

The three dead crows were identified as preliminarily positive by the Illinois Department of Agriculture lab in Galesburg. Samples from the birds have been shipped to the U.S. Geological Survey lab in Madison, Wis., for confirmatory testing that is expected to take several weeks.

The dead crows were found Sept. 11 and 12 in the following locations (collection dates are in parentheses): Midlothian, Cook County (Sept. 12); Posen, Cook County (Sept. 11); and Skokie, Cook County (Sept. 11).

In addition to the dead birds, three pools of mosquitoes collected by the Northwest Mosquito Abatement District in northwest Cook County have been preliminarily identified with West Nile virus. Samples of the mosquitoes will be sent to the U.S. Centers for Disease Control and Prevention (CDC) laboratory in Colorado for confirmation.

West Nile virus is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird.

West Nile virus is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird.

While most people infected with West Nile virus have no symptoms of illness, some may become ill, usually three to 15 days after the bite of an infected mosquito. When people do become ill, symptoms may be mild, such as a fever or headache. In some individuals, however, particularly the elderly and those with weakened immune systems, West Nile virus can cause serious disease that includes inflammation of the brain (encephalitis), muscle weakness, high fever, convulsions, paralysis, coma or death.

The following steps should be taken to reduce the risk of being bitten by mosquitoes:

• Stay indoors at dawn, dusk and in the early evening when mosquitoes are most active.
• Whenever outdoors during high-risk times, wear shoes and socks, long pants and a long-sleeved shirt.
• Use mosquito repellent containing 25 percent to 35 percent DEET when it is necessary to be outdoors, applied sparingly to exposed skin or clothing, as indicated on the repellent label. Consult a physician before using repellents on young children.
• Check residential screens, including porches and patios, for tears and other openings.
• Eliminate stagnant water in bird baths, ponds, flower pots, wading pools, old tires and other receptacles in which mosquitoes might breed.

(Editor's note: A complete recap of the positive birds and mosquitoes identified so far in Illinois is on the Department's Web site at www.idph.state.il.us. Go to the West Nile virus page and select "surveillance.").