What is Legionnaires' disease?

Outbreaks of Legionnaires’ disease often draw a lot of media attention, but the disease remains a mystery to the general public.

Legionnaires’  disease is caused by a bacteria  called Legionella pneumophila. The bacteria is found naturally in the environment, usually in warm water, such as in hot water tanks, large plumbing systems, parts of air conditioning systems of large buildings. People get Legionnaire’s disease when they breathe in air contaminated by droplets of water containing the bacteria.

“Many people worry that Legionnaires’ disease can be transmitted from person to person because outbreaks occur in people at the same location. Outbreaks happen when people become sick from the same exposure in the environment,” says Dr. Reena Lovinsky, Medical Director, Infection Prevention & Control with The Scarborough Hospital. “For example, if people staying at a hotel all breathe in the steam from a whirlpool spa that has not been properly cleaned and disinfected, a large number of people will get sick. The bacteria are spread in the air droplets from the whirlpool and not from person to person.”

Symptoms are similar to other types of pneumonia, which include high fever, chills, cough, muscle aches and headaches. Symptoms usually begin two to 10 days after being exposed to the bacteria. In rare instances, the illness can take up to 14 days after exposure to appear.

People who suspect they’ve been exposed or who are displaying symptoms should contact their doctor.   Some are at greater risk than others of contracting the disease:

•  65 years and older
• Smokers or people with chronic lung disease
• People  with weak immune systems such as diabetics and cancer or transplant patients

Most cases of Legionnaires’ disease can be successfully treated with antibiotics. Even with treatment, the disease can be fatal in five to 30 per cent of people with pre-existing severe medical problems.