Legionnaires' Disease


Legionnaires' disease is a lung infection. It is a form of pneumonia . It got its name from an outbreak at the American Legionnaires Convention in 1976.


This disease is caused by specific bacteria. The bacteria are most often found in sources of standing water. It may be found in cooling towers, HVAC systems, and air conditioners.

Legionnaires' disease can be contracted by breathing water vapor from a standing water source that contains the bacteria.

The Lungs
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The infection does not move from one person to another.

Risk Factors

Factors that may increase your chance of Legionnaires' disease include:

  • Advanced age
  • Smoking
  • Chronic lung disease
  • Weakened immune system
  • Kidney failure
  • Diabetes
  • Taking cortisone or other immunosuppressive drugs
  • History of organ transplant


Symptoms may include:

  • Fatigue
  • Fever (often high)
  • Chills and muscle aches
  • Cough
  • Headache


Your doctor will ask about your symptoms and medical history. A physical exam will be done.

Your doctor may need pictures of your chest. This can be done with a chest x-ray .

Your doctor may need tests of your bodily fluids. This can be done with:

  • Urine tests
  • Sputum tests
  • Blood tests


This disease is usually treated with antibiotics.


Proper design, maintenance, and cleaning of high-risk areas can reduce the risk of spreading the disease. This includes any area with standing water.


Please note, not all procedures included in this resource library are available at Allegiance Health or performed by Allegiance Health physicians.

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