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Epidemiology and pathogenesis of Legionella infection

Victor L Yu, MD
Janet E Stout, PhD
Nieves Sopena Galindo, MD
Section Editor
Stephen B Calderwood, MD
Deputy Editor
Sheila Bond, MD


Since the organism was first identified in 1976 during an outbreak at an American Legion Convention in Philadelphia, Legionella has been recognized as a relatively common cause of both community-acquired [1,2] and hospital-acquired pneumonia [3,4]. Legionellosis refers to the two clinical syndromes caused by bacteria of the genus Legionella:

Legionnaires' disease is the more common syndrome of pneumonia caused by Legionella species.

Pontiac fever is an acute, febrile, self-limited illness, which has been linked to Legionella species [5].

The incidence of Legionnaires' disease depends upon the degree of water reservoir contamination, the intensity of patient exposure to that water, and the susceptibility of the host. Successful diagnosis requires specialized laboratory tests, which are not always available.

The microbiology, epidemiology, and pathogenesis of Legionella infection will be reviewed here. Clinical manifestations, diagnosis, and treatment of this entity are discussed separately. (See "Clinical manifestations and diagnosis of Legionella infection" and "Treatment and prevention of Legionella infection".)

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Literature review current through: Nov 2017. | This topic last updated: Apr 07, 2016.
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