Legionnaires' Disease
Legionnaires' disease is a serious type of pneumonia caused by Legionella bacteria, typically contracted by breathing in mist from contaminated man-made water systems.
What is Legionnaires' Disease?
Legionnaires' disease is a serious type of pneumonia caused by Legionella bacteria. The disease was named after a group of people at an American Legion convention became ill with this type of pneumonia.
Legionella is found naturally in freshwater, such as lakes and rivers, and in soil. People usually only get sick when the bacteria grow and spread in man-made water systems, such as hot tubs, fountains, and the plumbing systems of large buildings like hotels or nursing homes. Legionella can also cause Pontiac fever, a milder, flu-like illness that does not infect the lungs.
Causes & Transmission
You can get the infection by breathing in mist or small drops of water that contain the bacteria. This mist may come from hot tubs, showers, or large building air conditioning units. You usually cannot get infected by drinking water containing the bacteria unless you aspirate it (accidentally breathe the water into your lungs). The bacteria do not spread from person to person.
Risk Factors
Most healthy people who come in contact with the bacteria do not become sick. You are more likely to develop an infection if you:
- Are over the age of 50
- Are a current or former smoker
- Have a chronic (long-lasting) disease such as diabetes or kidney failure
- Have a chronic lung disease such as COPD or emphysema
- Have a weakened immune system due to a disease such as HIV or cancer, or are taking medicines that suppress your immune system
- Live in a long-term care facility
- Have recently stayed in a hospital or had surgery requiring anesthesia
Symptoms
Symptoms usually show up 2 to 14 days after exposure. While most symptoms are similar to other types of pneumonia, Legionnaires' disease may also cause gastrointestinal symptoms and mental changes. Symptoms include:
- Cough
- High fever
- Chills
- Headache
- Chest pain
- Shortness of breath
- Fatigue
- Nausea and vomiting
- Diarrhea
- Confusion
Complications
Legionnaires' disease can cause life-threatening complications such as respiratory failure, kidney failure, and sepsis. About 1 out of every 10 people who get sick with the disease will die from complications.
Diagnosis & Treatment
To diagnose the disease, a health care provider will likely order a chest x-ray to check for pneumonia. If present, lab tests such as a urine or sputum test can check for Legionella bacteria. A blood test may also be used to check for exposure.
Treatment involves antibiotics, and most patients require hospital care. Getting treatment early increases the chances of recovery.
Prevention
You can lower your risk by:
- Cleaning all water-related devices regularly, including portable humidifiers, water heaters, air conditioners, and nasal rinses.
- Flushing faucets and showerheads that have not been used for a week or more by letting hot and cold water run for at least two minutes before use.
- Avoiding exposure to water sources like decorative fountains or hot tubs if you are unsure of their maintenance.
- Using windshield cleaner in your car's wiper fluid tank instead of water.
- Asking about the maintenance of water systems in buildings you visit.