Water Sanitation Health

Legionella and the prevention of legionellosis

This book provides a comprehensive overview of the sources, ecology and laboratory identification of Legionella. It provides guidance on assessment and management of risks associated with potentially hazardous environments, such as cooling towers, pools and spa baths. The document also identifies necessary measures to prevent, or adequately control, the risk of exposure to Legionella bacteria for each particular environment.

Outbreaks of legionellosis generally cause a high level of morbidity and mortality in the people exposed; therefore, the suspicion of an outbreak warrants immediate action. This publication reviews policies and practice for outbreak management and the institutional roles and responsibilities of an outbreak control team.

Legionellosis is a collection of infections that emerged in the second half of the 20th century, and that are caused by Legionella pneumophila and related Legionella bacteria. The severity of legionellosis varies from mild febrile illness (Pontiac fever) to a potentially fatal form of pneumonia (Legionnaires’ disease) that can affect anyone, but principally affects those who are susceptible due to age, illness, immunosuppression or other risk factors, such as smoking.

Water is the major natural reservoir for legionellae, and the bacteria are found worldwide in many different natural and artificial aquatic environments, such as cooling towers; water systems in hotels, homes, ships and factories; respiratory therapy equipment; fountains; misting devices; and spa pools.