People get legionellosis when they inhale water mist containing the bacteria.
Pontiac fever requires no treatment.
Legionnaires' disease is treatable with antibiotics. Outbreaks can usually be controlled by identifying and cleaning contaminated water sources. Legionellosis is a lung infection that can be mild or severe enough to cause death. In its mild form, it is called Pontiac fever. The more severe form of infection, a type of pneumonia, is called Legionnaires' disease.