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Measles cases are on the rise globally and here in Illinois the number is increasing as well. Vaccines are 97% effective in preventing this highly contagious disease.  To learn more about this infection and get information on vaccination, go to  Learn how to identify measles and the safe and effective vaccine that can prevent this potentially life-threatening infection for adults and children. 

WNV Surveillance

2023 West Nile Virus Surveillance Data

Data are updated by 5:00pm every Monday.

Case counts reflect cases completed by local health departments at the time of reporting.  Case counts may temporarily decrease if new information needs to be added, but will be included again when information is complete and the case is closed.  Case counts may differ from CDC due to the timing of the reports.

Illinois Birds, Mosquitoes, Horses and other Animals

Cumulative totals of West Nile virus infection in birds, mosquitoes and horses by county, municipality and date collected.

Bird, Mosquito, Horse and other Animal Statistics by County
Illinois Birds, Mosquitoes, Horses and other Animals Map

Surveillance Data by Year