Legionnaires' disease is similar to other types of pneumonia. To help identify the presence of legionella bacteria quickly, your doctor may use a test that checks your urine for legionella antigens — foreign substances that trigger an immune system response. You may also have one or more of the following:

  • Blood 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
  • A CT scan of your brain or a spinal tap (lumbar puncture) if you have neurological symptoms such as confusion or trouble concentrating


Legionnaires' disease is treated with antibiotics. The sooner therapy is started, the less likely the chance of serious complications or death. 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 or a primary care provider. However, in some cases, you may be referred to a doctor who specializes in treating lung disease (pulmonologist) or infectious diseases, or you may be advised to go to an emergency department.

What you can do

  • Write down key information about your illness, including all the symptoms you're experiencing. Record your temperature.
  • Tell your doctor if you've recently been away from home and where you stayed. If anyone you regularly associate with has an illness similar to yours, mention that to your doctor as well.
  • Write down personal information, including recent hospitalizations.
  • Make a list of all medications, vitamins and supplements you're taking.
  • Bring a family member or friend along, if possible. Someone who goes with you may help you remember the information your doctor provides.
  • Write down questions to ask your doctor.

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?
  • What are the alternatives to the approach you're suggesting?
  • 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 any other questions you have.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, including:

  • When did you begin experiencing symptoms?
  • 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.

Jan. 11, 2018
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  2. Legionella (Legionnaires' disease and Pontiac fever). Centers for Disease Control and Prevention. http://www.cdc.gov/legionella/index.html. Accessed March 22, 2016.
  3. Longo DL, et al., eds. Legionella infections. In: Harrison's Principles of Internal Medicine. 19th ed. New York, N.Y.: McGraw-Hill Education; 2015. http://accessmedicine.com. Accessed March 23, 2016.
  4. Yu VL, et al. Clinical manifestations and diagnosis of legionella infection. http://www.uptodate.com/home. Accessed March 23, 2016.
  5. Papadakis MA, et al., eds. Bacterial and chlamydial infections. In: Current Medical Diagnosis & Treatment 2016. 55th ed. New York, N.Y.: The McGraw-Hill Companies; 2016. http://www.accessmedicine.com. Accessed March 23, 2016.
  6. Yu VL, et al. Treatment and prevention of legionella infection. http://www.uptodate.com/home. Accessed March 23, 2016.