Chicago health officials have confirmed three cases of Legionnaires’ disease connected with a downtown hotel.

The Department of Public Health says people who stayed at the JW Marriott Chicago Hotel located at 151 W. Adams St. from July 16 to August 15 may have been exposed to Legionella. That’s a bacteria that can cause a respiratory infection.

The city and the hotel are in the process of contacting 8,500 individuals that stayed or worked at the hotel during that time.

Dr. Kathy Ritger with the Department of Public Health says people could’ve gotten the disease from a contaminated water source.

“People acquire it by breathing in aerosolized water, so it can be a mist or a vapor. So when we do an investigation about breaks of Legionnaire’s Disease we want to look at what potential water sources in the environment where people were together,” she said.

Ritger says the disease isn’t spread from person to person.

She says most people exposed to the bacteria do not become ill, but patrons who experience respiratory problems should check with a doctor. 

The hotel has taken all precautions including draining the hotel pool, hot tub and fountain. Officials say Legionnaires’ disease is no longer a threat at the hotel.