Legionella is a type of bacteria that is the cause of two lung diseases, Legionnaires’ Disease and Pontiac Fever. Legionnaires’ Disease is a serious type of pneumonia (lung infection). Pontiac Fever is a less severe respiratory disease that causes flu-like symptoms. Rarely, Legionella can cause infections outside of the lungs, such as heart or wound infections.
Legionnaires’ disease symptoms are similar to other types of pneumonia. Antibiotics are used to treat Legionella infections. Most healthy people exposed to Legionella don’t get sick. However, certain factors such as smoking status, older age, and health issues or conditions put some people at increased risk for getting Legionnaires’ disease.
Legionella bacteria are naturally found in freshwater environments, like lakes and streams. However, the bacteria are more likely to cause illness when they get into building water systems and are poorly controlled. Once Legionella grows and multiplies in a building water system, it can spread to people in a few ways. People most commonly get sick by breathing in mist, or small droplets of water that contain the bacteria. People can also get sick by accidentally swallowing (aspirating) water into the lungs.
The source of Legionella bacteria in outbreaks are often from hot tubs that are not cleaned and disinfected properly, shower heads, cooling towers, plumbing systems, and mist machines. Outbreaks are commonly associated with buildings or structures that have complex water systems, such as hotels and resorts, long-term care facilities, hospitals, and cruise ships. The key to preventing Legionnaires’ disease is to reduce the risk of Legionella growth and spread. Water management programs help building owners control Legionella.