Legionnaires' Disease

What is Legionnaires' disease?
Legionnaires' disease is caused by a type of bacteria called Legionella. The Legionella bacteria are found naturally in the environment, usually in water. The bacteria grow best in warm water, like the kind found in:
  • Hot tubs
  • Cooling towers
  • Hot water tanks
  • Large plumbing systems
  • Decorative fountains
How is it spread?
People get Legionnaires' disease when they breathe in a mist or vapor (small droplets of water in the air) containing the bacteria. One example might be from breathing in droplets sprayed from a hot tub that has not been properly cleaned and disinfected. The bacteria are not spread from one person to another person. Most people exposed to the bacteria do not become ill.

What are the symptoms?
Legionnaires' disease can have symptoms like many other forms of pneumonia, so it can be hard to diagnose at first. Signs of Legionnaires' disease can include:
  • Cough
  • Shortness of breath
  • High fever
  • Muscle aches
  • Headaches
These symptoms usually begin 2 to 14 days after being exposed to the bacteria.

How can I protect myself?
The key to preventing legionellosis is maintenance of the water systems in which Legionella grow, including drinking water systems, hot tubs, decorative fountains, and cooling towers. There are no vaccines that can prevent legionellosis. Persons at increased risk of infection may choose to avoid high-risk exposures, such as being in or near a hot tub.

Most healthy individuals do not become infected with Legionella bacteria after exposure. People at higher risk of getting sick are:

  • Older people (usually 50 years or older)
  • Current or former smokers
  • Those with a chronic lung disease (like COPD or emphysema)
  • Those with a weak immune system from diseases like cancer, diabetes, or kidney failure
  • People who take drugs that suppress (weaken) the immune system (like after a transplant operation or chemotherapy)
How is Legionnaires' disease treated?
Legionnaires' disease requires treatment with antibiotics (drugs that kill bacteria in the body), and most cases of Legionnaires' disease can be treated successfully with antibiotics. Healthy people usually get better after being sick with Legionnaires' disease, but hospitalization is often required.