What is Legionellosis?
Legionellosis is an infection caused by a bacterium, Legionella pneumophila. The disease has two forms: Legionnaire’s Disease (the more severe form) and a milder illness – Pontiac fever.
Legionella bacteria are found naturally in the environment, usually in water. Legionella thrives in warm water, such as that found in hot tubs, hot water tanks or parts of the air conditioning systems of large buildings.
What causes Legionellosis?
People can inhale the bacteria when they breathe in small droplets of water in air that has been contaminated. The bacteria are not spread from person-to-person.
What are the symptoms?
Symptoms are like many other forms of pneumonia, so it may be difficult to diagnose at first. Signs can include high fever, chills, and a cough. Some people may also suffer from muscle aches and headaches. The symptoms of Pontiac Fever are fever and muscle aches without pneumonia. Cases generally recover within 2 to 5 days.
When do symptoms begin?
Symptoms of Legionnaire’s disease may begin within two to ten days, usually five to six days, after exposure to the bacteria. Symptoms of Pontiac Fever may begin within five to 66 hours, usually within 24-48 hours, after exposure to the bacteria.
How do you test for it?
Several laboratory tests can be used to diagnose Legionellosis. The most common method is through urine testing.
Who is at risk?
People most at risk of getting sick are older people (usually 65 years of age and older) as well as people who smoke, or those who have a chronic lung disease such as emphysema. People with weak immune systems, such as individuals with cancer or kidney failure, are also at higher risk.
How is it treated?
Most cases can be treated with antibiotics. Healthy people usually recover from the infection. Older people with other health problems may require further medical attention.
Reference
Heymann, D. L., (2008). Control of Communicable Diseases Manual. (19th Ed.). Washington, DC: American Public Health Association.
