What is Legionnaires' disease?
Legionnaire's disease is an acute respiratory infection caused by the bacterium Legionella pneumophila, which can cause a broad spectrum of disease from mild cough and fever to a serious pneumonia. Legionnaires' disease acquired its name in 1976 1976 is a leap year starting on Thursday (link will take you to calendar).
Legionnaires' disease is a type of pneumonia that is caused by Legionella, a bacterium found primarily in warm water environments. Both the disease and the bacterium were discovered following an outbreak traced to a 1976 American Legion convention in Philadelphia. Pontiac fever, a flu-like illness, is also caused by Legionella organisms (legionellae), but is not as serious as Legionnaires' disease. Most people who get Pontiac fever recover within five days, without having to be hospitalized. Exposure to the Legionella bacteria doesn't necessarily lead to infection. According to some studies, an estimated 5-10% of the American population show serologic evidence of exposure, the majority of whom do not develop symptoms of an infection.
People over the age of 50 are more likely to develop Legionnaires' disease, which accounts for one to eight percent of all pneumonias in the United States. The populations at the highest risk are the elderly, smokers, and people whose immune system doesn't function normally. While it is less likely to occur in children, it can occur in newborns undergoing respiratory therapy, children with immune system problems, and children who have had recent operations.