|This micrograph depicted details seen in a lung tissue specimen from a Knoxville patient with fatal pneumonia due to Legionnaires’ disease. The tissue was stained using hematoxylin-eosin (H&E) stain. Legionella pneumophila are Gram-negative bacteria. Using H&E stain, these organisms, if present in the specimen, would stain a pink or red color. Note how the alveolar spaces are so congested with a leukocytic infiltrate in response to the infection.|
How serious is it? What is the treatment?
Legionnaires' disease can be very serious and can cause death in up to 5% to 30% of cases. Most cases can be treated successfully with antibiotics, and healthy people usually recover from infection.
How do people get Legionnaires’ disease?
People get Legionnaires' disease when they breathe in a mist or vapor (small droplets of water in the air) that has been contaminated with the bacteria. One example might be from breathing in the steam from a whirlpool spa that has not been properly cleaned and disinfected.
The bacteria are NOT spread from one person to another person.
Outbreaks are when two or more people become ill in the same place at about the same time, such as patients in hospitals. Hospital buildings have complex water systems, and many people in hospitals already have illnesses that increase their risk for Legionella infection.
Other outbreaks have been linked to aerosol sources in the community, or with cruise ships and hotels, with the most likely sources being whirlpool spas, cooling towers (air-conditioning units from large buildings), and water used for drinking and bathing.