The patients range from 40 to 80 years old and reside on the Northwest and South sides. The patients’ symptoms began in late July or early August, according to the Chicago Department of Public Health.

Chicago public health officials on Tuesday confirmed the city's first three human cases of West Nile virus in 2025.

Lake County intensifies mosquito control efforts to combat West Nile virus, following increased numbers of infected mosquitoes in the area, and local health officials advise residents on protective measures.

Chicago reported three human cases of West Nile virus in the last month as city officials warn the risk of contracting the virus is "high," with more mosquitoes testing positive than usual.