A Cook County jail detainee has been diagnosed with Legionnaires’ disease, prompting health concerns for other inmates and workers at the correctional facility.

The infected inmate was recovering at Stroger Hospital Wednesday, according to the Cook County sheriff’s office, and the tier where he was being held has since been evacuated. A notice was sent to corrections officers in the division to contact their personal doctors.

Legionnaires is bacterial infection that is a severe form of pneumonia. The detainee had “pneumonia-like symptoms” on July 6 when he was transferred to the hospital and tested positive for the disease, according to the sheriff's department.

Infection is most likely to manifest in the elderly, those with weak immune systems, and smokers, health officials say.

The disease cannot be contracted from person-to-person, but rather through inhaling mist from hot tubs, pools, and air conditioning systems in large buildings.

It was unsettling for some Cook County jail visitors.

"What actions have they taken?” said Rolando Ramirez, who was at the facility Wednesday morning visiting a friend in the jail. “Hopefully a company is there that knows about the cleaning procedures."

The sheriff’s office maintains the detainee is an isolated case, and that other inmates were moved from the man’s tier only out of “an abundance of caution.”

Cook County Jail houses approximately 9,000 detainees daily at the facility.