West Nile virus found in Illinois mosquitoes

May 13 2004

Dr. Whitaker said the Illinois Department of Public Health was notified by DuPage County of the findings as part of the county's routine surveillance for West Nile virus. The dead crow was found Monday (May 10) in Downers Grove and the mosquito pools were collected May 6 in Wayne and Monday (May 10) in Darien.

"Illinois has seen West Nile virus activity the past three years and it is not a surprise to see a positive test result reported in the spring," Dr. Whitak er said. "These reports simply underscore the fact that the state and local health departments have in place a very aggressive surveillance effort for West Nile and other mosquito-borne diseases."

In 2003, the first positive bird for West Nile virus was reported May 21 in Henderson County. In all, last year 75 of the state's 102 counties were found to have a West Nile positive bird, mosquito, horse or human case. A total of 54 human cases of West Nile disease, including one fatality, were reported last year in Illinois.

In 2002, the state led the nation with 884 human cases, including 66 deaths, and West Nile activity was reported in 100 of 102 counties.

Surveillance for West Nile virus began May 1 and includes collecting dead crows and blue jays. Citizens who observe a sick or dying crow or blue jays should contact their local health department, which will determine if the bird is to be picked up for testing.

Gov. Rod R. Blagojevich announced Tuesday that the state has awarded grants to local health departments totaling $2.3 million for the detection and control of West Nile virus and other mosquito-borne diseases.

WNV 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.

Dr. Whitaker said West Nile infections can be mild and include fever, headache and body aches, or can be severe and marked by headache, high fever, neck stiffness, stupor, convulsions, muscle weakness, paralysis and, rarely, death. Serious West Nile virus illness is most often present in individuals 50 years of age or older.

Dr. Whitaker said individuals can reduce their risk of West Nile disease and other mosquito-borne diseases by taking these precautions:

• 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 according to label instructions.
• Consult a physician before using repellents on young children. Make sure doors and windows have tight-fitting screens. Repair or replace screens that have tears or other openings.
• 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.

Additional information about West Nile virus can be found on the Department's Web site: www.idph.state.il.us/envhealth/wnv.htm.