When reports of a pneumonia epidemic at an American Legion convention in Philadelphia first hit the news back in the 1970s, most people had never heard of what was to become known as Legionnaires' disease. But over the past decade, reported cases of Legionnaires' disease—a severe form of bacterial pneumonia—have almost tripled.

In 2012, two people died of the disease in Chicago after contracting Legionnaire's in a downtown hotel. In July 2015, an outbreak of Legionnaire's disease was reported in New York, NY. By the end of that month, 31 cases and 2 deaths had been reported in the south Bronx. The outbreak resulted in more than 100 cases and 12 deaths by mid-August 2015.

The U.S. Centers for Disease Control and Prevention (CDC) reported that recorded cases of Legionnaires' disease rose 217 percent during the years 2000 to 2009. In 2009, more than 3,500 cases were reported. The highest increases were seen in older adults, particularly in those 80 and older.

Yet these numbers don't tell the whole story. Experts suspect that cases are drastically under-reported. The CDC says that, in reality, between 8,000 and 18,000 Americans are hospitalized each year for Legionnaires' disease.

Legionnaires' disease may conjure up pictures of rampant illness on cruise ships or in hotels, but the truth is that you can just as easily get the disease from your own hot tub. The bacteria that causes the disease, Legionella, grows naturally in water, especially warm water in man-made environments. You can get Legionnaires' disease by inhaling steam, mist or vapor droplets of contaminated water, which can be found in whirlpool spas, decorative fountains and air-conditioning units and water systems in large buildings.

You can't, however, catch Legionnaires' disease from someone else. You're most susceptible to Legionnaires' disease if you are

  • 50 years or older
  • a smoker
  • suffering from a weakened immune system or chronic lung disease
  • using medicine that suppresses your immune system, such as chemotherapy drugs

Symptoms are similar to those of other types of pneumonia: muscle aches, high fever, chills, cough and headaches.

While you can't do anything about contaminated water and cooling systems in buildings and public pools and spas, you can prevent Legionnaires' disease by keeping your own hot tub or swimming pool meticulously clean and disinfected.

Treatment for Legionnaires' disease involves an antibiotics regimen. Antibiotics are normally effective, but 5 to 30 percent of cases can be fatal, especially among people who are hospitalized for the disease, who started antibiotics late or who have a coexisting illness. The sooner you're diagnosed, the better chance you'll have for a full recovery.

Source: Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50; Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 16 Jul 2013

Last Modified: 11 Aug 2015