Chicago-area patients may have been exposed to TB

Patients at several Chicago-area hospitals may have been exposed to tuberculosis through a health care worker.

Northwestern Memorial Hospital said Friday that it's contacting 17 patients who may have been affected. The hospital said it's evaluating another 100 patients who may have been cared for by health care worker at its Prentice Women's Hospital from Nov. 3 to 21.

Northwestern said it believes the risk of exposure is extremely low. The Chicago Department of Public Health says the worker was contagious while working at Children's Memorial Hospital and Evanston Hospital.

The Illinois Department of Public Health and Centers for Disease Control and Prevention are also investigating.