There is no evidence of the infection being spread from person to person. People of any age may get Legionnaires' disease, but there are some people who are at higher risk. Legionnaires' disease most often affects middle-aged and older persons. People who smoke cigarettes or have chronic lung disease are particularly at risk. Symptoms of Legionnaires' disease include fever, chills, and a cough that may be dry or produce sputum.
Some patients have muscle aches, headache, tiredness, and loss of appetite.
A chest x-ray may show pneumonia. Legionnaires' disease is diagnosed by special tests. These can include finding the Legionella bacteria in sputum, finding Legionella antigens in urine samples, and looking at antibody levels in blood samples. Legionnaires' disease is treated with antibiotics. Usually erythromycin or rifampin is used.