1. Legionnaires’ disease got its name from a 1976 outbreak at an American Legion convention in Philadelphia. After returning home from the convention, a number of Legionnaires began experiencing mysterious symptoms like fevers that reached 107 degrees, as well as pneumonia (a lung infection). By the following month, 6 of the 14 infected men had died, reports the Times, yet laboratory tests couldn’t determine a cause for the illnesses.The outbreak quickly made front page news amid fears of an epidemic. Six months after the initial cases were identified, doctors discovered that the illness was caused by a bacterium, which they named Legionella pneumophila. Legionella grows in warm water, and the outbreak at the convention was spread by the hotel’s air-conditioning system.


2. Two different illnesses are caused by Legionella bacteria.

They are Legionnaires' disease and Pontiac fever, according to the Centers for Disease Control and Prevention (CDC). Someone with Legionnaires’ disease has pneumonia, while a person with Pontiac fever has a non-pneumonia influenza-like illness that is milder. Pontiac fever and Legionnaires’ disease share similar symptoms: cough, shortness of breath, high fever, muscle aches, and headaches. But unlike Legionnaires’ disease, Pontiac fever goes away without treatment.

3. Legionnaires’ disease is hard to diagnose because it shares signs and symptoms with other conditions.

Symptoms of the disease usually begin 2 to 14 days after a person is exposed to the bacteria.

Lung infection is common with Legionella because the bacteria thrive in the warm, moist environment of the lungs.

4. Legionnaires’ disease is treatable.

While most cases are successfully treated with antibiotics, patients often still require hospitalization. It can be fatal, and some people are more likely to become seriously ill after contracting the disease. This includes people over 50, smokers, people with a chronic lung disease such as COPD, and people with a weakened immune system.

5. Legionnaires’ disease is a common cause of severe pneumonia that requires hospitalization.

Eight thousand to 18,000 Americans are hospitalized due to Legionnaires’ disease each year, but only about 3,000 cases are reported to the CDC.

6. Legionnaires’ disease has some complications.

Respiratory failure, septic shock, and acute kidney failure are all complications associated with the disease. Early treatment with antibiotics is the best line of defense against complications.

7. Legionella bacteria are usually found in water.

The bacteria occur naturally in the environment, says the CDC, and grow best in warm water.

Specific areas where you might encounter the bacteria include: cooling towers, hot tubs and whirlpool spas, hot water tanks, decorative fountains or pools, and large plumbing systems.

8. The disease doesn’t spread from person to person.

Instead, Legionnaires’ disease is contracted by breathing in mist, steam, or vapor that has been contaminated with the bacteria.

9. Recent travel and smoking can raise your risk of contracting Legionnaires’ disease.

More than 20 percent of cases of Legionnaires’ disease may be associated with recent travel. Legionnaires’ disease outbreaks have been linked to hot tubs and whirlpools on cruise ships, swimming pools, and water systems in hotels, hospitals, and nursing homes. The Mayo Clinic reports that smoking may actually increase your risk of developing Legionnaires’ if you’re exposed to the bacteria.

10. Legionnaires’ disease is preventable.

The most effective way to prevent the infection is to make sure that water systems like cooling towers, spas, and pools are properly maintained and up to current health and safety codes. You can purchase pool test strips to verify that your water is properly maintained.