Preventing legionnaires' disease: environmental health expertise is key.

Author:Kunz, Jasen

About 5,000 cases of Legionnaires' disease and at least 20 outbreaks are now reported to the Centers for Disease Control and Prevention (CDC) each year (Adams et al., 2015). People can get Legionnaires' disease or Pontiac fever (collectively known as legionellosis) by inhaling aerosolized water droplets containing Legionella bacteria (Fields, Benson, & Besser, 2002). Legionnaires' disease, the more serious type of legionellosis, can cause severe pneumonia (lung infection) and is deadly for about 1 in 10 people who get it (Dooling et al., 2015). Pontiac fever causes a milder, influenza-like illness. Legionnaires' disease was named after an outbreak of pneumonia in 1976 among people attending an American Legion convention in Philadelphia.

Legionella is rarely, if ever, transmitted from person-to-person (Correia et al., 2016); it is found naturally in the environment, usually in warm water. Exposure to freshwater generally does not lead to disease. In human-made water systems, however, Legionella can amplify and spread to susceptible hosts via aerosolization from contaminated water. As such, keeping Legionella out of building water supplies and cooling towers, as well as pools, hot tubs, and fountains, is key to preventing infection and outbreaks (Garrison et al., 2016). Prevention is critical as Legionella was the cause of 66% of all potable water-associated outbreaks reported to CDC during 2011-2012 (Beer et al., 2015).

Environmental Health Expertise Is Key

To prevent Legionnaires' disease we must understand the environmental factors that allow Legionella bacteria to survive and reach a susceptible host. Due to the relationship of Legionella to the environment, environmental health practitioners are ideally situated to provide expertise essential to both responding to Legionnaires' disease outbreaks and preventing future ones. Working with epidemiologists and public health laboratorians, environmental health practitioners need to be proficient in applying environmental interventions (e.g., recommending potable water flushing procedures to address Legionella-contaminated water in an unoccupied building wing) in outbreak settings to stop outbreaks and prevent future ones. Environmental health response in Legionnaires' disease outbreaks contributes to improved prevention practices. Additionally, they can help translate lessons learned from outbreak response into evidence-based prevention guidance for building owners and managers.

In June 2016...

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