Waterborne Infectious Diseases in Health-Care Facilities – Legionellosis


Legionellosis is a collective term describing infection produced by Legionella spp., whereas Legionnaires disease is a multi-system illness with pneumonia. The clinical and epidemiologic aspects of these diseases (Table 1) are discussed extensively in another guideline. Although Legionnaires disease is a respiratory infection, infection-control measures intended to prevent healthcare-associated cases center on the quality of water—the principal reservoir for Legionella spp. Table 1. Clinical and epidemiologic characteristics of legionellosis/Legionnaires disease

Legionella spp. are commonly found in various natural and man-made aquatic environments and can enter health-care facility water systems in low or undetectable numbers. Cooling towers, evaporative condensers, heated potable water distribution systems, and locally-produced distilled water can provide environments for multiplication of legionellae. In several hospital outbreaks, patients have been infected through exposure to contaminated aerosols generated by cooling towers, showers, faucets, respiratory therapy equipment, and room-air humidifiers. Factors that enhance colonization and amplification of legionellae in man-made water environments include
a. temperatures of 77°F–107.6°F [25°C–42°C],
b. stagnation,
c. scale and sediment, and
d. presence of certain free-living aquatic amoebae that can support intracellular growth of legionellae.
The bacteria multiply within single-cell protozoa in the environment and within alveolar macrophages in humans.

Tuesday, April 26. 2022


Centers for Disease Control and Prevention (CDC)- Guidelines for Environmental Infection Control in Health-Care Facilities

Please Check out file at the following link

Modes of Transmission of Waterborne Diseases

Principles of Cleaning and Disinfecting Environmental Surfaces

Heating, Ventilation, and Air Conditioning Systems in Health-Care Facilities

Modes of Transmission of Airborne Diseases

Environmental Infection Control in Health-Care Facilities