What is Legionella?

Legionella is a bacteria found in freshwater, such as lakes or streams. It can spread to humans when it grows in human-made water systems such as hot tubs, water heaters, plumbing systems, cooling towers, and decorative fountains. It usually grows in warmer water.

How does Legionella spread?

Legionella spreads by a person breathing in infected water droplets. It can also spread when a person drinks water “down the wrong pipe”, meaning it goes through the trachea and into the lungs rather than through the digestive tract.

Who is at an increased risk for Legionellosis?

Most healthy people will not get sick from Legionella. Those at risk for getting sick include:

  • People over 50 years old
  • Current or former smokers
  • People with chronic lung diseases
  • People with weak immune systems
  • People who take drugs that weaken the immune system

What are the symptoms of Legionellosis?

Legionellosis causes Legionaires’ disease, which is similar to other types of pneumonia. Symptoms usually begin between 2 days and 2 weeks after exposure. Symptoms include:

  • Cough
  • Shortness of breath
  • Fever
  • Muscle aches
  • Headaches

Occasionally symptoms may include:

  • Diarrhea
  • Nausea
  • Confusion

Legionella may also develop Pontiac Fever, which is a more mild form of Legionellosis. People with Pontiac Fever do not have pneumonia.

How is Legionellosis diagnosed?

  • Chest x-ray
  • Urine test
  • Sputum sample
  • Blood test

How is Legionellosis treated?

Legionaires’ disease is treated with antibiotics. 90% of people will recover fully, but 1 in 10 patients will die of complications.

Pontiac fever eventually goes away on its own.

How can Legionellosis be prevented?

The best way to prevent Legionellosis is to maintain water systems in order to stop the growth of Legionella bacteria.

For more information on Legionellosis, visit http://www.cdc.gov/legionella/index.html.