Legionnaires’ disease is a bacterial infection that can cause fatal pneumonia. It is carried by amoeba that thrive in stagnant water, and is most common in older people and people who have chronic lung disease. Creative Commons

Health officials have connected the death of an elderly woman in northwest Alabama on Thursday to an outbreak of Legionnaires’ disease, a serious and life-threatening type of pneumonia. According to the Associated Press, there were 13 lab-confirmed cases of Legionnaires’ at a nursing home in Florence, a city 206 miles north of Montgomery.

The death of the 80-year-old woman, who was not named, marks the first death associated with the Legionnaires’ disease outbreak at the center. She died Thursday in a hospital in Tuscaloosa.

Authorities identified the outbreak of Legionnaires’ earlier this month. Health officials determined the center of the outbreak to be a northwest Alabama nursing home, the Associated Press reported Wednesday. The exact source of the disease is still under investigation.

Ten of the 13 people infected with Legionnaires’ disease were residents of the northwest Alabama nursing home belonging to Glenwood Healthcare. The three others, including the woman who died on Thursday, were visitors to the home.

Legionnaires’ disease was first coined in 1976 when 34 people were killed at a convention in Philadelphia of the American Legion, a veterans’ organization that includes members of the U.S. armed forces.

More than 2,000 people, mostly men, attended the convention. Two hundred were sickened by the outbreak. Health investigators traced the cause of the infections to a bacterium called Legionella, which circulated through the convention hotel’s air conditioning system.

In August of this year, Ohio experienced its largest outbreak of Legionnaires’ disease when five people were killed and 39 others became sick at a retirement community in Reynoldsburg. Victims of the outbreak at Wesley Ridge Retirement Community ranged in age from 63 to 99, according to the Associated Press.

Here are five things to know about Legionnaires’ disease and Legionella bacteria:

Legionnaires’ disease is a severe form of pneumonia and is caused by a bacterium called Legionella. It is a serious and life threatening disease that affects between 8,000 and 18,000 people in the U.S. every year, according to the U.S. Centers for Disease Control and Prevention, or CDC. People with Legionnaires’ disease will have pneumonia.

The bacteria responsible for the disease are found naturally in the environment and thrive in warm water.

Symptoms of Legionnaires’ disease include chills, high fever, coughing, muscle aches and headaches. Symptoms usually occur between two and 14 days after exposure. Because symptoms of Legionnaires’ disease are similar to those of pneumonia, the disease is often hard to diagnose at first.

Exposure to Legionnaires’ occurs when people inhale mist or water vapor contaminated with Legionella bacteria. Legionella bacteria grow best in warm water. Decorative fountains, hot tubs, cooling towers and hot water tanks are all places where the bacteria can thrive.

Legionnaires’ is not spread from person to person.

Most people exposed to Legionnaires’ disease don’t become sick. According to the CDC, just because someone in your workplace or residence was diagnosed with Legionnaires’ disease, doesn’t mean you’ve been exposed.

Those most at risk of contracting Legionnaires’ disease are people older than 50, smokers, those with a chronic lung disease and those with a weak immune system, according to Medline Plus.

Legionnaires’ is treated with antibiotics. Most treatments of Legionnaires’ are successful. Hospitalization is usually required, however. Possible complications include lung failure, and death occurs in 5 to 30 percent of cases.