Scanning electron micrograph of Legionella pneumophila bacteria
The cause: A bacterium, Legionella
How you get it: Usually from inhaling the bacteria, which tends to grow in moist environments such as around hot tubs, plumbing systems and in air-conditioning systems of large buildings. It rarely spreads by person-to-person contact.
The symptoms: High fever, cough, chills, headache muscle pain. The bacteria infect the lungs and can cause a severe form of pneumonia.
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The treatment: Antibiotics such as quinolones and macrolides
The prognosis: Can be fatal in up to 30% of cases, but prompt treatment with antibiotics usually cures the disease.
Did you know? The disease got its name after the bacteria sickened a group of American Legion members at a meeting in Philadelphia in 1976. Recent outbreaks include one originating from bacteria spread by a decorative fountain that bubbled water in a Wisconsin hospital lobby. Each year, anywhere from 8,000 to 18,000 people in the U.S. are hospitalized with the disease.