That brings to eight the number of human cases of the mosquito-borne illness in the state.
Public health officials say the new cases include the state's first human case in Cook County. It involved a 24-year-old woman from northern Cook County who was hospitalized with West Nile encephalitis last month and has since been released.
The two other new cases are a 41-year-old man from Sangamon County and an 84-year-old man from Piatt County, both with West Nile fever.
The Piatt County man was hospitalized and later released, while the Sangamon County man never required hospitalization.
Illinois led the nation with 884 human cases of West Nile and 66 deaths.