Legionella and the environment

Legionella can cause two distinct diseases. The first one is Legionnaires’ disease, which is characterized by a pneumonia with a significant mortality rate. The second disease is Pontiac fever, a nonpneumonic, self‐limiting, febrile disease with a high attack rate. This review analyzes the growth, identification, survival, and pathogenicity of Legionella isolated from environmental sources including soil, mud, showers, nebulizers, potable water, water from streams, lakes, water storage tanks, evaporative condensers, cooling towers, and humidifers. The importance of algal metabolites and Flavobacterium for the growth requirements of Legionella in aquatic habitats and plumbing systems is critically evaluated. The final section of the review describes the efficacy of various methods for decontamination of environmental sources of Legionella.