What is legionellosis?
Legionellosis is an infection caused by bacteria called Legionella. There are two forms of the disease: Legionnaires’ disease, which can be severe and include pneumonia, and Pontiac fever, a mild respiratory illness.
Legionnaires' disease was named in 1976 when an outbreak of pneumonia occurred among persons attending a convention of the American Legion in Philadelphia.
Who is at risk for the disease?
People of any age may get Legionnaire’s disease, but it most often affects middle-aged and older persons, especially those who smoke cigarettes or have chronic lung problems. Persons with suppressed immune systems due to illnesses such as cancer, diabetes or AIDS, or drug therapy are also at increased risk for legionellosis.
How is it spread?
You can get legionellosis through the air by breathing in mists from a water source containing the bacteria. The bacteria can be found in many places in the environment, such as plumbing systems and hot water tanks, air-conditioning cooling towers, whirlpool spas, and in contaminated soil at digging sites. Legionellosis is not spread from person to person and is not associated with car or household window air conditioners.
What are the symptoms?
The first symptoms of Legionnaires’ disease are muscle aches, headache, loss of appetite, tiredness, and cough. These symptoms are often followed by chills, diarrhea, and high fever. Chest X rays may indicate progressive pneumonia. It is difficult to distinguish the disease from other types of pneumonia by symptoms alone. Other tests are needed to diagnose the disease.
The symptoms of Pontiac fever are fever and muscle aches, with no pneumonia.
When do symptoms start?
The time between exposure to the bacteria and the beginning of symptoms of Legionnaires’ is 5 or 6 days, but the onset can range from 2 to 10 days. For Pontiac fever, it is shorter – usually a few hours to 2 days.
What is the treatment for legionellosis?
A doctor can prescribe medicines to treat legionellosis.
How can you keep from getting it?
Because Legionella bacteria can be found in many places in the environment, there is very little one can do on an individual basis to prevent exposure. However, some preventive measures can be taken by industry to reduce the risks. These measures include the periodic draining and cleaning of cooling towers, and the use of chemicals to prevent the growth of slime-forming organisms in air conditioning cooling towers and evaporative condensers.