The Illinois Department of Public Health has confirmed through laboratory tests the second human West Nile virus case in Illinois for 2007.
The Cook County woman is in her 50s and became ill in the latter part of June.
?So far this year there are only three counties reporting West Nile virus positives in Illinois, compared with 21 counties this time last year. However, this is the second human West Nile virus case of 2007,? said Dr. Eric E. Whitaker, Illinois Department of Public Health Director. ?Even though we have not seen widespread mosquito activity, you still need to protect yourself against mosquito bites.?
Positive mosquito samples reported this year include DuPage County on May 8, Tazewell County on May 17 and Cook County on May 24. The first human case for 2007 was reported in DuPage County on June 15.
In 2006, the first positive mosquito sample was reported May 24th in DuPage County and the first human case was reported August 1 in St. Clair County. Last year 77 of the state?s 102 counties were found to have a West Nile positive bird, mosquito, horse or human case. A total of 215 human cases of West Nile disease, including 10 deaths, were reported last year in Illinois.
Surveillance for West Nile virus in Illinois began May 1st 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 is to 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 14 days after the bite of an infected mosquito.
Only about two persons out of 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.