01:03 - Source: CNN
What is Legionnaires' disease? (2015)
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Legionnaires’ disease is a serious type of pneumonia caused by the Legionella bacterium, which is found in fresh water, according to the US Centers for Disease Control and Prevention.

The bacteria can be found in shower heads and faucets, hot tubs, cooling towers, hot water tanks, decorative fountains or plumbing systems in large buildings.

How does someone get it?

People breathe in small droplets of water that contain the bacteria, the CDC says.

How do I tell whether I have Legionnaires’?

Symptoms are a cough, shortness of breath, high fever, muscle aches and headaches. The symptoms begin two to 10 days after exposure. A doctor will check for pneumonia and might order a urine or a phlegm test to see whether the Legionella bacteria has caused the lung infection.

Can I get it from someone else?

“In general, people do not spread Legionnaires’ disease to other people,” the CDC says. The Mayo Clinic says you cannot get it from person-to-person contact.

How many people die from Legionnaires’?

About one in 10 people with Legionnaires’ disease dies, according to the CDC. Legionnaires’ disease is treated with antibiotics, and most people who get sick make a full recovery.

How many cases are there a year?

About 7,500 US cases of Legionnaires’ disease were reported to the CDC in 2017, the agency said, adding that it’s likely an underestimate because the illness is underdiagnosed. The reported rate of people who get Legionnaires’ disease has risen by 550% since 2000.

There are a variety of factors to the rising number of cases, including a true increase in people getting the disease because of more at-risk people but also because of increased reporting.

How do we prevent it?

There are no vaccines that can prevent Legionnaires’ disease. Instead, according to the CDC, Legionnaires’ disease can be prevented by making sure that “building owners and managers maintain building water systems in order to reduce the risk of Legionella growth and spread.”

Who is most at risk?

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    People 50 or older, current or former smokers and people with chronic lung disease or weak immune systems. “Avoiding smoking is the single most important thing you can do to lower your risk of infection,” the Mayo Clinic says.

    Where does the name come from?

    There was an outbreak at an American Legion convention in Philadelphia in 1976. The CDC said 29 people died and 180 people got sick from being at the conventional hotel.