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What is Legionellosis?

Infection with Legionella (also called legionellosis) can vary in severity from a mild febrile illness, Pontiac Fever, to a serious and sometimes fatal form of pneumonia - Legionnaires' disease. Both illnesses are caused by the bacteria Legionella, which is naturally found in freshwater sources such as lakes and streams. However, Legionella bacteria can grow and spread in human-made water systems, such as hot tubs, cooling towers (which use water to cool air as part of centralized air conditioning systems for buildings or industrial processes), hot water tanks, decorative fountains, and large buildings with complex water systems. Small water droplets or mist from these sources can contain Legionella bacteria, which people can inhale, causing an infection in the lungs. To date, there has been no reported direct person-to-person transmission of Legionella. The best way to prevent legionellosis is to reduce exposure to water sources where Legionella grows. Click the image below to enlarge it.

Legionella Transmission

Alabama's Health: Legionnaires' Disease

For more information on legionella and Legionnaires' Disease, read our blog post at Alabama's Health.

Page last updated: April 24, 2024