URL of this page: https://www.nlm.nih.gov/medlineplus/legionnairesdisease.html

Legionnaires' Disease

Also called: Legionellosis 


Legionnaires' disease is a type of pneumonia caused by bacteria. You usually get it by breathing in mist from water that contains the bacteria. The mist may come from hot tubs, showers, or air-conditioning units for large buildings. The bacteria don't spread from person to person.

Symptoms of Legionnaires' disease include high fever, chills, a cough, and sometimes muscle aches and headaches. Other types of pneumonia have similar symptoms. You will probably need a chest x-ray to diagnose the pneumonia. Lab tests can detect the specific bacteria that cause Legionnaires' disease.

Most people exposed to the bacteria do not become sick. You are more likely to get sick if you

  • Are older than 50
  • Smoke
  • Have a chronic lung disease
  • Have a weak immune system


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