Legionnaires' Disease

What is Legionnaires' disease

Legionnaires' disease is a type of pneumonia caused by legionella bacteria. Legionella bacteria like to live in fresh water. They can make you sick if you breathe in mist or water vapor that contains the bacteria.

Legionnaires' disease usually spreads through:

  • Hot tubs that aren't properly drained and cleaned
  • Swimming pools
  • Air conditioning systems in large buildings
  • Showers and large plumbing systems
  • Decorative fountains

Legionnaires' disease is sometimes also called legionellosis.

Who is at risk for Legionnaires' disease?

Even if you're exposed to the bacteria that cause Legionnaires' disease, you may not get sick. You may get Legionnaires' disease if you:

  • Are older than 50
  • Have a weakened or suppressed immune system
  • Smoke or used to smoke
  • Have a chronic lung disease

Unlike some other types of pneumonia, you usually can't catch Legionnaires' disease from another person.

Diagnosing and testing for Legionnaires' disease

The symptoms of Legionnaires' disease are similar to other types of pneumonia. They can include:

  • Cough
  • Shortness of breath
  • Chest pain
  • High fever and chills
  • Headache
  • Body aches

To diagnose Legionnaires' disease, your doctor will listen to your lungs, perform a physical exam and do some blood tests to figure out which type of bacteria is causing your symptoms. You may also need a chest X-ray.

If you think you may have been exposed to Legionnaires' disease, talk to your doctor immediately to be treated with antibiotics. If you ignore the symptoms, it can become serious or even life threatening.

The legionella bacteria can also cause a milder disease called Pontiac fever, which is similar to the flu. Pontiac fever doesn't affect your lungs, and it often clears up on its own in a few days.



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