(Legionnaires' disease, Pontiac fever, and extrapulmonary legionellosis)
Legionellosis includes three clinically distinct illnesses, Legionnaires’ disease, Pontiac fever, and extrapulmonary legionellosis, that are all caused by exposure to Legionella bacteria. Legionnaires’ disease most commonly presents as pneumonia. Pontiac fever is a milder, influenza-like illness, and extrapulmonary legionellosis happens when there is disease outside the lungs, (e.g., heart) and diagnostic testing reveals evidence of Legionella at that site.
Healthcare-Associated Legionnaires' Disease