According to the Mayo Clinic, Legionnaires' disease is a severe form of pneumonia. The disease does not come from person-to-person contact, rather the bacteria usually is inhaled. The Mayo Clinic website states that older adults, smokers and people with weakened immune systems are most at risk.
The disease usually develops after 14 days and symptoms include headache, muscle pain, chills and a fever that could be 104 degrees. Other symptoms include cough that could include blood, chest pain, fatigue, loss of appetite and gastrointestinal symptoms.
Both men are currently listed in stable condition, NBC Chicago reports.
Patch will have more information as it becomes available.