- from news release -

Freeport, IL – The Stephenson County Health Department (SCHD) reports today that a dead crow collected in rural Cedarville has been confirmed positive for West Nile Virus.

To date this season, SCHD has tested 17 birds and 95 mosquito batches from all over the county; none of the mosquito batches has tested positive for the West Nile Virus. This summer from throughout the state the Illinois Department of Public Health (IDPH) has reported 5 WNV-positive birds, 45 positive mosquito batches, and no human cases. Stephenson County reported one human case of West Nile Virus in 2008.

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.

Only about two people in 10 who are bitten by an infected mosquito will experience any illness. Illness from West Nile Virus is usually mild, and includes fever, headache, and body aches, but serious illnesses, such as encephalitis and meningitis, and even death are possible.

The number of West Nile Virus-positive humans, mosquitoes, and birds has been lower this year than in previous years. Likely causes for the reduced 2009 WNV activity are below-normal temperatures throughout the summer and flushing of catch basins and other Culex mosquito production sites by frequent heavy rains. Additionally, many local agencies have increased their larviciding programs since the 2002 WNV outbreak.

The risk to humans decreases in cooler temperatures because:

1) mosquitoes will stop flying when air temps are below 50o F (when mosquitoes aren't flying, they aren't biting), and

2) in cooler weather, people are outdoors less and they wear more clothes (less skin to bite).

However, the risk of WNV will not be gone until we get a hard freeze that kills annual vegetation. Incidentally, Culex mosquitoes go into winter "hibernation" around the end of September, and the females survive the winter in hidden areas such as crawl spaces, caves, and tunnels.

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:

1. Avoid being outdoors when mosquitoes are most active, especially between dusk and dawn. Use prevention methods whenever mosquitoes are present.

2. 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.

3. 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.

4. Eliminate all sources of standing water that can support mosquito breeding, including stagnant 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.

Additional information about West Nile Virus can be found on the IDPH web site at http://www.idph.state.il.us/envhealth/wnv.htm.

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