Bacteria can be found in shower heads and taps, hot tubs, cooling towers, hot water tanks, decorative fountains or plumbing systems in large buildings.
The CDC says that people breathe in small drops of water containing bacteria.
Symptoms include coughing, shortness of breath, high fever, muscle aches and headaches. Symptoms begin 2 to 10 days after exposure. Your doctor will check for pneumonia and may order a urine or phlegm test to check if Legionella has caused a lung infection.
Can I get it from someone else?
"In general, people don't transfer Legionnaires' disease to other people," says CDC. The Mayo Clinic says you can't get it from personal contact.
How many people die of Legionnaires?
According to the CDC, about 1 in 10 people with legionnaires' disease die. Legionnaires' disease is treated with antibiotics, and most patients get sick completely.
How many cases per year?
The agency informed the CDC about approximately 7,500 US cases of Legionnaires' disease in 2017, adding that this is probably an underestimation because the disease is undiagnosed. The percentage of people who suffer from legionnaires has increased by 550% since 2000.
The growing number of cases is associated with many factors, including the actual increase in the number of people suffering from this disease due to the greater number of people at risk, but also due to the increased number of reports.
How to prevent this?
There are no vaccines that could prevent Legionnaires' disease. Instead, according to the CDC, Legionnaires' disease can be prevented by making sure that "building owners and managers maintain water supply systems to reduce the risk of Legionella growth and spread."
Who is most at risk?
People 50 years or older, current or past smokers, and people with chronic lung disease or a weak immune system. "Avoiding smoking is the most important thing you can do to reduce the risk of infection," says Mayo Clinic.
Where does the name come from?
In 1976, an American Legion congress broke out in Philadelphia. The CDC reported that 29 people had died and 180 people had fallen ill because of staying in a conventional hotel.