SPRINGFIELD, IL – The Illinois Department of Public Health today reported that two dead crows found July 18 in LeRoy in McLean County have tested positive for West Nile virus.

A total of 117 birds and five mosquito pools in 32 Illinois counties have tested positive this year for West Nile virus since surveillance for the mosquito-transmitted virus began May 1. No human cases of West Nile encephalitis have been reported in Illinois.

A complete listing of the positive birds and mosquito pools identified so far in Illinois, by county, is available on the Department's Web site at www.idph.state.il.us. Go to the West Nile virus page and select "2002" under surveillance.

The Culex or house mosquito, which can carry West Nile virus or St. Louis encephalitis, breeds in warm, stagnant water and begins to increase in numbers early in the summer. Recent temperatures have been ideal for the rapid development and activity of the Culex mosquito and, as a result, a jump in the number of positive birds.

Hospitals and infectious disease physicians have been notified of the increase in detection of birds with West Nile virus and reminded to order tests for arbovirus infections for patients with appropriate symptoms.

Dr. John R. Lumpkin, state public health director, said identification of positive birds is a reminder that the virus is present throughout the state and the following precautions should be taken to reduce the risk of any mosquito-borne disease:

• Whenever outdoors between dusk and dawn, wear shoes and socks, long pants and a long-sleeved shirt. Loose-fitting, light colored clothing is best.
• 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 for and repair any tears in residential screens, including porches and patios.
• Eliminate stagnant water in bird baths, ponds, flower pots, wading pools, old tires and any other receptacles in which mosquitoes might breed.

In 2002, West Nile virus activity has been detected in at least 28 states, including Illinois, and Washington, D.C., in the United States and three Canadian provinces. There have been at least 13 human cases of West Nile encephalitis confirmed this year – 11 in Louisiana, one in Texas and one in Mississippi.

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.

West Nile virus was first confirmed in Illinois in September 2001 when two dead crows from the Chicago metropolitan area tested positive for the virus. A total of 138 birds from seven Illinois counties (Cook, Crawford, DuPage, Kane, Lake, McHenry and Will) tested positive for the virus last year. In addition, two horses – one from Cook County and one from Kane – tested positive for the virus in 2001.

2002 West Nile virus surveillance information can be found on the Department's Web site at www.idph.state.il.us/envhealth/wnvsurveillance_data_02.htm.