Legionnaires' disease has killed three people who stayed at the JW Marriott in downtown Chicago.

A third person, 66-year-old Thomas Keane of Ireland, died after contracting Legionnaires' disease at the hotel. There have been 10 reported cases of the disease from people who stayed at the hotel.  The infected people stayed at the JW Marriott between July 16 and Aug. 15.

After conducting tests, officials from the Chicago Department of Public Health have determined that the disease likely came from the spa and a decorate fountain in the main lobby of the Marriott, located at 151 W. Adams St.  Samples from the fountain, the spa whirlpool and the locker rooms of the spa tested positive for the Legionella that was found within the infected patients.

Legionnaires' disease is a severe form of pneumonia that comes from Legionella bacteria which live in warm water. The bacteria can be breathed in from water particles in the air. Symptoms start to show two weeks after exposure and include a high fever, headache and chills. This then develops into pneumonia-like symptoms, such as a cough, chest pain or shortness of breath.

Hotel officials removed the fountain which was the primary cause of the infection. The spa whirlpool and locker rooms have been closed off to guests. There were no traces of Legionella found within the hotel rooms.

The hotel remains open and is working with a water safety consulting company and they're installing cleaner water systems. Dr. Kathleen Ritger, medical director over communicable disease at the CDPH tells IBTimes that the hotel is now safe, but warnings are being given to guests who stayed at the hotel earlier in the summer.

"We believe that there is no ongoing health threat at the hotel," she said. "Individuals who stayed at the hotel during this time period [July 6 to Aug. 15] who are experiencing flu-like symptoms are encouraged to get in touch with a healthcare provider because it is important that all potential cases are diagnosed and treated as soon as possible to shorten the recovery period and help prevent serious complications."

It is believed that 8,500 people stayed at the hotel during the time which the other infected guests stayed. The CDPH has set up a hotline and over 100 people have called to report symptoms and to ask questions.

Between 8,000 and 18,000 people are infected with Legionnaires' each year in the U.S., according to the federal Centers for Disease Control and Prevention. Most people exposed to Legionella do not become sick, but between five and 30 percent of cases are fatal.  

Quebec City in Canada is also dealing with a Legionnaires' disease outbreak. At least 169 people have been infected since July and 11 have died. City officials believe it stems from cooling towers around the city.