Fight the Bite! Preventing West Nile Virus
About West Nile Prevention Insect Repellent Pets & Livestock For Kids
 

Photo of mosquitoAbout West Nile Virus

West Nile virus first emerged in the United States in the New York metropolitan area in the fall of 1999. Since then, the virus, which can be transmitted to humans by the bite of an infected mosquito, has quickly spread across the country and, this year, reached California.

Mild cases of West Nile infections may cause a slight fever or headache. More severe infections are marked by a rapid onset of a high fever with head and body aches, disorientation, tremors, convulsions and, in the most severe cases, paralysis or death. Usually symptoms occur from three to 14 days after the bite of an infected mosquito. Persons at the highest risk for serious illness are those 50 years of age or older.

The best way to prevent West Nile encephalitis and other mosquito-borne illnesses is to reduce the number of mosquitoes around your home and neighborhood and to take personal precautions to avoid mosquito bites.

Incidences in Illinois

In Illinois, West Nile virus was first identified in September 2001 when laboratory tests confirmed its presence in two dead crows found in the Chicago metropolitan area. In 2002, birds, mosquitoes and horses in 100 of the state's 102 counties were reported positive for West Nile virus and the first human cases and deaths from West Nile virus illness in Illinois were reported in August 2002. By the end of the year, the state lead the nation with more than 800 human cases and 62 deaths. The Illinois Department of Public Health (IDPH) maintains a sophisticated disease surveillance system to monitor animals and insects that can potentially carry the virus: dead crows and blue jays, mosquitoes and horses. Mosquitoes can either carry the virus or get it by feeding on infected birds. The surveillance system also includes infectious disease physicians, hospital laboratory directors and infection control practitioners, local health departments and staff from IDPH's laboratory, environmental health and infectious diseases divisions who test for and report suspect or confirmed cases of various diseases that can be caused by mosquito-borne viruses.

Human Cases in Illinois

Map

Cases and Deaths by County

County Cases Deaths
Adams 1 0
Champaign 2 0
Clark 2 0
Clinton 6 0
Coles 1 0
Cook  -  (Suburban Cook 407, Chicago 227) 634 37
Crawford 3 0
Cumberland 3 0
DeKalb 2 0
DeWitt 1 0
DuPage 49 3
Edgar 2 1
Effingham 7 1
Ford 1 0
Fulton 8 3
Hancock 1 0
Henderson 2 0
Henry 1 0
Jackson 6 1
Jasper 2 0
Jefferson 1 1
Kane 9 1
Kankakee 1 0
Kendall 2 1
Knox 1 1
Lake 8 1
LaSalle 11 0
Logan 1 0
Macon 9 3
Macoupin 6 0
Madison 14 2
Marion 1 0
Mason 1 0
McLean 3 0
McHenry 1 0
Menard 1 0
Montgomery 4 0
Moultrie 1 1
Peoria 6 0
Rock Island 2 0
Saline 1 0
Sangamon 13 4
Shelby 3 0
St. Clair 14 0
Stark 1 0
Stephenson 1 0
Tazewell 1 0
Vermilion 3 0
White 1 1
Whiteside 1 0
Will 18 0
Williamson 2 0
Winnebago 1 0
TOTAL 877 62

Cases by Age and Sex

 Age Male Female Total % Per Age
 0-14 9 9 18 2.05
 15-29 29 25 54 6.15
 30-44 89 100 189 21.55
 45-59 102 127 229 26.11
 60-74 111 96 207 23.60
 75+ 89 88 177 20.18
 Unknown 3 0 3 0.34
 TOTAL 432 445 877  
 % Male or Female 49.00 51.00    

Source: Illinois Department of Public Health