Legionellosis (Legionnairesā disease, Pontiac fever)
Legionellosis is a disease caused by Legionella bacteria that can cause mild respiratory illness or pneumonia. Most cases occur as single isolated events. Outbreaks are relatively rare. There are two distinct forms of the disease: āLegionnaires' diseaseā and āPontiac fever.ā Legionnairesā disease is named after a large outbreak at an American Legion convention in Philadelphia in 1976.
Transmisson
Legionnaires' disease is spread via:
- Environment to person when they breathe in a mist or small droplets of water in the air that contains the bacteria. The bacteria grow best in warm water, and are known to have been found in:
- Showerheads and sink faucets
- Cooling towers (structures that contain water and a fan as part of centralized air-cooling systems for buildings or industrial processes)
- Hot tubs
- Decorative fountains and water features
- Hot water tanks and heaters
- Large, complex plumbing systems
Personātoāperson spread does not occur. (Only one case of possible person-to-person transmission has ever been reported.) Outbreaks may occur following the exposure of many individuals to a common source of the bacteria in the environment, including places like hotels, hospitals, and other large buildings, when the water supply becomes contaminated. Most healthy individuals do not develop symptoms after exposure to Legionella, and symptomatic infection is rare in people younger than 20.
Risk Factors, the disease most often affects:
- older individuals (ā„50)
- males
- current or former smokers
- immunocompromised individuals
- underlying illnesses such as chronic lung disease, cancer, diabetes, or kidney failure.
It is unknown at this time if past infection gives people immunity.
Symptoms
Symptoms of legionellosis are:
- Muscle aches
- Headache
- Tiredness
- Loss of appetite
- Dry cough
- High fever (102Ā°F to 105Ā°F)
- Chills
- Diarrhea
Chest X-rays often show pneumonia in Legionnaires' disease, which may lead to death, especially in those with weakened immune systems. Pontiac fever is a milder illness with symptoms like Legionnairesā disease but does not progress to pneumonia or death. Symptoms of Pontiac fever go away in two to five days without treatment.
The period between exposure and onset of illness for Legionnaires' disease is two to 10 days but is often five to six days and can be up to 19 days; for Pontiac fever, it is one to two days but can be as short as four hours.
Diagnosis
Legionellosis is usually diagnosed by a health care provider using a variety of laboratory tests including culture and antigen testing.
Treatment
Antibiotics given by a health care provider can be used to treat the disease.
Prevention
The key to preventing Legionnairesā disease is to reduce the risk of Legionella growth and spread. Building owners and managers can use a water management program to reduce the risk of Legionella growing and spreading. General guidelines for legionellosis prevention include cleaning and/or chlorinating areas known to be reservoirs in reported outbreaks, such as decorative water fountains, air conditioning cooling towers, humidifiers, whirlpool spas, and respiratory therapy devices.
For more information about the treatment of legionellosis, contact your health care provider or visit https://www.cdc.gov/legionella/php/laboratories/?CDC_AAref_Val=https://www.cdc.gov/legionella/clinicians/di agnostic-testing.html.
Exclusion Guidance
People should not be excluded from child care, school, work, or other activities unless the general exclusions apply.
- All others can attend work and other functions as long as they are well enough to do so and can practice good hand washing and respiratory etiquette.