Carl R. Darnall Army Medical Center - Health Library

Legionnaires Disease

(Legionnaires Pneumonia)

Definition

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.

Causes ^

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 is not spread from one person to another.

Risk Factors ^

Factors that may increase the chances of Legionnaires disease:

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

Symptoms ^

Symptoms may include:

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

Diagnosis ^

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

Treatment ^

This disease is usually treated with antibiotics.

Prevention ^

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

RESOURCES:

Centers for Disease Control and Prevention
https://www.cdc.gov

National Institute of Environmental Health Sciences
https://www.niehs.nih.gov

CANADIAN RESOURCES:

Nova Scotia Health Authority
http://www.nshealth.ca

Public Health Agency of Canada
https://www.canada.ca

REFERENCES:

Arcavi L, Benowitz NL. Cigarette smoking and infection. Arch Intern Med. 2004;164(20):2206-2216.

Community-acquired pneumonia in adults. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T115170/Community-acquired-pneumonia-in-adults. Updated December 18, 2017. Accessed February 16, 2018.

Legionella infections. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T904756/Legionella-infections. Updated May 20, 2016. Accessed February 16, 2018.

Legionella infections. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/infectious-diseases/gram-negative-bacilli/legionella-infections. Updated May 2016. Accessed February 16, 2018.

Legionella (Legionnaires' disease and Pontiac fever). Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/legionella/about/index.html. Updated May 31, 2016. Accessed February 16, 2018.

Last reviewed February 2018 by EBSCO Medical Review Board David L. Horn, MD, FACP  Last Updated: 5/2/2014