Legionnaires Disease: What is it?

Legionnaire’s Disease is a serious type of pneumonia that typically is caused by inhaling water vapor or mist containing the Legionella bacteria. Once it enters the body, the bacteria can rapidly multiply and infect the lungs.

Although less common, Legionnaires disease can also occur via pulmonary aspiration — when water or other liquid contaminated with the bacteria is accidentally ingested into the lungs.

Legionnaires Disease Symptoms:

Legionnaires Disease Rising In The US.Symptoms of Legionnaires disease manifest in various forms of pulmonary distress, including coughing, shortness of breath, fever, muscle aches, and headaches. This form of pneumonia can also result in nausea, diarrhea, and confusion.

The disease can develop into a life-threatening infection if left untreated, especially for people older than 50; current or former smokers; people with a pre-existing lung disease; people with a weakened immune system or anyone who takes drugs that weaken immunity; people with cancer; and people with other underlying diseases, such as diabetes, kidney disease, or liver disease.

According to the U.S. Centers for Disease Control and Prevention (CDC), one in 10 people who contract Legionnaires disease will die. The death rate can be much higher when an outbreak occurs in a nursing home, hospital, or other building with a population of people in frail or poor health.

Symptoms usually develop within 10 days of exposure, but it can take up to two weeks for signs of the illness to become apparent.

Legionnaires disease is not contagious, and it can only be spread from person to person in extremely rare circumstances. No special precautions are needed in treating and interacting with infected persons.

For those who survive Legionnaires disease, full recovery can be a long and sometimes dispiriting process. A follow-up study of 122 patients who survived a giant outbreak of the disease in the Netherlands found that 75% of the patients suffered from a persistence of fatigue for months after the outbreak. Researchers also found that 66% of the patients continued to suffer neurologic symptoms and 63% suffered neuromuscular symptoms for months afterward. The study provided one of the best-documented glimpses of how the disease can continue to impact the quality of life for those who survive.

1976 Philadelphia Legionnaires Disease Outbreak

Legionnaires disease gets its name from an outbreak that occurred at the annual three-day American Legion convention at the Bellevue-Stratford Hotel in Philadelphia in July 1976. The outbreak was the first time the disease was identified.

The first death of an attendee of that conference occurred on July 27, three days after the event ended. In the days that followed, several more conference attendees, mostly male veterans, died from the mysterious disease. Two weeks after the end of the American Legion conference, 182 illnesses were reported. Of those, 29 people who attended the event (16%) died. The outbreak is regarded as one of the worst U.S. medical tragedies of the 20th century.

Where Does Legionnaires Come From?

The Legionella bacteria is found naturally in lakes, ponds, streams, and other freshwater environments, but it becomes a health risk when it multiplies to form high concentrations inside human-made water systems.

In January 1977, health officials investigating the 1976 outbreak of Legionnaires disease in Philadelphia found Legionella bacteria to be breeding inside the cooling tower of the Bellevue-Stratford Hotel’s air conditioning system. From there, the bacteria was circulated throughout the hotel in water vapor form through the air conditioning vents.

It is now known that the cooling towers for centralized air conditioning systems are a common source of Legionnaires disease outbreaks. The bacteria can also thrive in hot water tanks and heaters, large industrial plumbing systems, improperly cleaned or maintained hot tubs, spas, and pools, decorative fountains and water features, water hoses, showerheads, and faucets.

The 1977 discovery of the Philadelphia outbreak source prompted health regulators around the world to introduce new regulations and safety standards for climate control systems.

Legionnaires Disease Trends

The number of cases reported to the CDC has steadily risen in the U.S. since 2000. According to the agency, about 7,500 cases of the disease are reported by state health departments every year. However, the number of actual cases is certainly much larger, the CDC says, because it is an underdiagnosed and underreported disease. According to the nonprofit organization Legionella.org, the number of Legionnaires disease cases each year in the U.S. is as high as 18,000.

Because the bacteria thrive in warm-water environments, most outbreaks occur in the summer and early fall, but they can happen at any time of the year. Major outbreaks of the disease occur all over the world. In fact, the largest known outbreaks of Legionnaires disease to date occurred in Murcia, Spain, in 2001, with more than 800 cases, and Bovenkarspel, Netherlands, in 1999, with more than 300.

Recent Legionnaires Outbreaks

Atlanta Sheraton Linked to Legionnaires Disease

Image of hot tub at Sheraton Atlanta Hotel Downtown , – Yelp ( K.W.)

A Legionnaires outbreak at the Sheraton Atlanta Hotel Downtown in June and July is 2019 the largest known outbreak of the disease in Georgia history. Georgia health officials are investigating more than 63 probable cases and have confirmed 12.

One of those sickened, 49-year-old Cameo Garrett, died from a Legionnaires infection in August 2019 after attending a Top Ladies of Distinction Conference at the hotel in June.

Flint Michigan Water Crisis

Fifteen top health officials in Michigan face criminal charges after their alleged mishandling of the Flint, Michigan, water supply led to at least 90 people being stricken with Legionnaires disease. Twelve of those died from their illness.
Serious problems with Flint’s water supply emerged after state and local officials switched from the Detroit water system and started drawing water from the Flint River in 2014 without properly treating the water first.

Because it wasn’t treated, the water contained high levels of various contaminants, including Legionella bacteria and lead.

New York City Legionnaires Outbreaks

Twelve people were diagnosed with the disease in the Bronx, New York, in December 2014 after inhaling the bacteria from a contaminated cooling towers at a housing development. The following July and August 2015, another unrelated outbreak in the Bronx sickened at least 120 people, including 12 fatally.

Investigators found the people were sickened from a cooling tower on top of a hotel. At the end of September, another 13 people were sickened in yet another Bronx Legionnaires disease outbreak, including one fatally. In all three cases, health officials found that industrial cooling towers hosted the bacteria.

Disneyland Legionnaires Outbreak

In the fall of 2017, 22 cases of Legionnaires disease were associated with an outbreak at Disneyland in Anaheim, California. Investigators believe the outbreak stemmed from a cooling tower that sprayed mist to cool visitors during excessively hot days. Droplets of the contaminated water likely spread to park visitors and even a few people outside the park.

Illinois Veterans’ Home Outbreak

An outbreak of Legionnaires disease sickened more than 50 people and killed 12 at the Illinois Veterans’ Home in Quincy, Illinois. Health officials linked that outbreak to a contaminated water supply at the 200-acre campus.

These are just some of the dozens of outbreaks that occur each year in the U.S. According to the CDC, 20-24 outbreaks of Legionnaires disease occur annually in the U.S.


On average, the mortality rate for Legionnaires disease is about 10%, but that number can be higher or lower depending on the circumstances. The fatality rate has ranged from 5% to 30% during various outbreaks. When outbreaks or individual infections occur in hospitals, the disease has a fatality rate approaching 30%.

If you become sickened with pneumonia-like symptoms, it is imperative that you be evaluated by a doctor. Be sure to mention if you may have been exposed to the Legionella bacteria, have used a hot tub, spent any nights away from home, or stayed in a hospital in the last two weeks.

Experienced Legionnaires Disease Attorneys

Beasley Allen has represented clients who suffered from a Legionnaires outbreak at an Alabama hotel and recently filed lawsuits for Atlanta Sheraton guests. If you have cases involving death or injuries as a result of developing Legionnaires disease, we would like to work with you.


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