Legionnaires' disease is a serious type of pneumonia caused by Legionella bacteria. People can get Legionnaires' disease by breathing in mist or accidentally swallowing water into the lungs that contain these bacteria. Legionella bacteria are found naturally in freshwater environments, but become a human health concern when they grow and spread in large building water systems. The number of cases of Legionnaires' disease reported in both the US and Montana has increased over the past two decades.
Common Sources of Infection
People who have Legionnaires' disease have commonly been exposed to the bacteria by one of the following sources:
- shower heads and sink faucets
- cooling towers (structures that contain water and a fan as part of a centralized air cooling system)
- hot tubs
- decorative fountains and water features
- hot water tanks and heaters
- large plumbing systems
Signs and Symptoms
Common signs and symptoms of Legionnaires' disease include:
- shortness of breath
- muscle aches
Symptoms typically begin 2 to 10 days after exposure to the bacteria, but it can be up to two weeks in some cases.
The best way to prevent illness occurring from Legionella is to make sure building owners and managers develop, implement, and maintain a water management program. CDC has developed a toolkit focused on large water systems to help people understand what type of buildings need a Legionella water management program, and how to develop it.
CDC Water Management Program Toolkit
The main principles of effective water management include:
- maintaining water temperatures outside the ideal range for Legionella growth (the bacteria survive at temperatures between 68 and 140 degrees Fahrenheit)
- preventing water stagnation
- ensuring adequate disinfection
- maintaining devices to prevent scale, corrosion, and biofilm growth, all of which provide a habitat and nutrients for Legionella
For more information on Legionnaires' disease and how to prevent it, visit the CDC Legionella webpage
Additional occupational resources can be found on the OSHA webpage