Legionnaires' disease is similar to other types of pneumonia. To help identify the presence of legionella bacteria quickly, your doctor might use a test that checks your urine for legionella antigens — foreign substances that trigger an immune system response. Other tests might include:

  • Blood and urine tests
  • Chest X-ray, which doesn't confirm Legionnaires' disease but can show the extent of infection in your lungs
  • Tests on a sample of your sputum or lung tissue


Legionnaires' disease is treated with antibiotics. The sooner therapy is started, the less likely the chance of developing serious complications. In many cases, treatment requires hospitalization. Pontiac fever goes away on its own without treatment and causes no lingering problems.

Preparing for your appointment

You're likely to start by seeing your family doctor. In some cases, you might be referred to a doctor who specializes in treating lung disease (pulmonologist) or infectious diseases, or you might be advised to go to an emergency department.

What you can do

Make a list of:

  • Key information about your illness, including your symptoms and when they began. Record your temperature.
  • Relevant personal information, including recent hospitalizations and whether you've recently traveled and where you stayed.
  • All medications, vitamins and other supplements you take, including doses.
  • Questions to ask your doctor.

Bring a family member or friend along, if possible, to help you remember the information your doctor provides.

Questions you might ask your doctor include:

  • What is likely causing my symptoms?
  • What are other possible causes?
  • What tests do I need?
  • What is the best course of action?
  • I have other health conditions. How will this illness affect them?
  • Is it possible to avoid hospitalization? If not, how many days will I be hospitalized?

Don't hesitate to ask other questions.

What to expect from your doctor

Your doctor is likely to ask you questions, including:

  • Have your symptoms been continuous?
  • Have your symptoms been worsening since their onset?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?

What you can do in the meantime

To avoid making your condition worse, follow these tips:

  • Don't smoke or be around smoke.
  • Don't drink alcohol.
  • Stay out of work or school, and rest as much as you can.
  • Drink plenty of fluids.

If you get sicker before you see a doctor, go to an emergency room.

May 24, 2021

  1. Murdoch D, et al. Microbiology, epidemiology, and pathogenesis of Legionella infection. https://www.uptodate.com/contents/search. Accessed Aug. 5, 2019.
  2. Legionella (Legionnaires' disease and Pontiac fever). Centers for Disease Control and Prevention. https://www.cdc.gov/legionella/about/index. Accessed Aug. 5, 2019.
  3. Jameson JL, et al., eds. Legionella infections. In: Harrison's Principles of Internal Medicine. 20th ed. The McGraw-Hill Companies; 2018. https://accessmedicine.mhmedical.com. Accessed Aug. 5, 2019.
  4. Murdoch D, et al. Treatment and prevention of legionella infection. https://www.uptodate.com/contents/search. Accessed Aug. 5, 2019.
  5. Legionellosis. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/legionellosis. Accessed Aug 9, 2019.

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