Risk factors
By Mayo Clinic staffNot everyone exposed to legionella bacteria becomes sick. You're more likely to develop the infection if you:
- Smoke. Smoking damages the lungs, making you more susceptible to all types of lung infections.
- Have a weakened immune system as a result of HIV/AIDS or certain medications, especially corticosteroids and drugs taken to prevent organ rejection after a transplant.
- Have a chronic lung disease such as emphysema or another serious condition such as diabetes, kidney disease or cancer.
- Are 65 years of age or older.
- Have a job maintaining the cooling towers in air conditioning systems.
Legionnaires' disease is a sporadic and local problem in hospitals and nursing homes, where germs may spread easily and people are vulnerable to infection.
- Pedro-Botet ML, et al. Epidemiology and pathogenesis of Legionella infection. http://www.uptodate.com/home/index.html. Accessed Oct. 13, 2010.
- Patient facts: Learn more about Legionnaires' disease. Centers for Disease Control and Prevention. http://www.cdc.gov/legionella/patient_facts.htm. Accessed Oct. 13, 2010.
- Edelstein PH, et al. Legionella. In: Mandell GL, et al. Mandell, Douglas, and Bennett's Principles and Practices of Infectious Diseases. 7th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2010. http://www.mdconsult.com/books/linkTo?type=bookPage&isbn=978-0-443-06839-3&eid=4-u1.0-B978-0-443-06839-3..00232-0. Oct. 14, 2010.
- Pedro-Botet ML, et al. Treatment and prevention of legionella infection. http://www.uptodate.com/home/index.html. Accessed Oct. 13, 2010.
- Top 10 things every clinician needs to know about legionellosis. Centers for Disease Control and Prevention. http://www.cdc.gov/legionella/top10.htm. Accessed Oct. 13, 2010.
- Pedro-Botet ML, et al. Clinical manifestations and diagnosis of legionella infection. http://www.uptodate.com/home/index.html. Accessed Oct. 13, 2010.
- Neil K, et al. Increasing incidence of legionellosis in the United States, 1990-2005: Changing epidemiologic trends. Clinical Infectious Diseases. 2008;47:591.
- Nhu Nguyen TM, et al. A community-wide outbreak of Legionnaires disease linked to industrial cooling towers — How far can contaminated aerosols spread? Journal of Infectious Diseases. 2006;193:102.
- Centers for Disease Control and Prevention, et al. Legionnaires' disease associated with potting soil — California, Oregon, and Washington, May-June 2000. MMWR. 2000;49:777. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4934a1.htm. Accessed Oct. 19, 2010.
- Legionellosis. World Health Organization. http://www.who.int/mediacentre/factsheets/fs285/en/index.html. Accessed Oct. 19, 2010.
- Sabria M, et al. Legionella infection. In: Fauci AS, et al. Harrison's Principles of Internal Medicine. 17th ed. New York, N.Y.: McGraw-Hill Medical; 2008. http://www.accessmedicine.com/content.aspx?aid=2871241. Accessed Oct. 13, 2010.
- Cunha BA. Legionnaires' disease: Clinical differentiation from typical and other atypical pneumonias. Infectious Disease Clinics of North America. 2010;24:73.


Find Mayo Clinic on