How Legionnaires Disease Got Its Name– Nothing Groovy About It!

Culture | December 5, 2018

November 24, 1976 - Members of the Pennsylvania American Legion confer among themselves while waiting to testify before a special congressional inquiry into the cause of the Mysterious Legionnaires Disease. (Getty Images)

Legionnaires Disease was officially diagnosed and named after a fateful American Legion Convention in Philadelphia, Pennsylvania in 1976. There were 4,500 American Legionnaires that descended on the City of Brotherly Love for their annual convention. Each year the organization convenes its convention in a different U.S. city. As you probably know, the American Legion is an organization that began in 1919 for veterans of the United States armed forces. Men and women come together in brotherhood and sisterhood out of pride for their service. The convention itself is the main draw but sightseeing and spending time with old friends catching up is a close second.

1976 was also the year of the Bicentennial, America’s 200th birthday.

The Liberty Bell (mapsofworld.com)

The three-day convention began on July 21, 1976. In addition to the Legionnaires, the city was also full of tourists. Philadelphia is home to the famous Liberty Bell and was a huge attraction for the Bicentennial. The city’s hotels and streets were packed to capacity and the number of people in the city was staggering.

Shortly after the big convention, the Legionnaires returned to their respective homes where many of them became ill.

The first reported deaths following the convention occurred exactly 8 days after it ended. Within 3 weeks, 11 more deaths had been reported. The main thing all of these veterans had in common, besides their service in the armed forces, was that they had all attended the Legionnaires Convention in Philadelphia that year.  

Publications on Legionnaires Disease (ibtimes.com)

Prior to officially being known as Legionnaires Disease, this sudden illness that paralyzed the city of Philadelphia was referred to as “the mystery disease.” The Center for Disease Control (CDC) was stumped!

Although this illness mimicked Pneumonia, it was soon discovered that it was something else altogether different. Patients were experiencing lung issues and were getting fevers as high as 107 degrees. By the time the CDC had begun its investigation, 20% of the convention participants had been affected and that number was quickly rising. Many theories as to the cause of the illness were plausible but nothing definitive had been discovered.

CDC investigators had many theories as to the cause of the illness that was feared to be an epidemic.

1976 Philadelphia, PA Sanitation Workers’ Strike (cainimages.com)

Garbage accumulated at the Legionnaire’s Convention due to the sanitation workers’ strike in Philadelphia in 1976.

There was a lot going on in Philadelphia during the convention. The city was packed with tourists and visitors. Coincidentally, during this same time period, the city’s sanitation workers were on strike. The garbage was not being collected and was piling up. With the sheer number of people in the city at the time adding to the growing mass of garbage, many suspected that the uncollected waste and a growing rat problem because of it was possibly the culprit making people sick.

During this time, there was a major foreign policy dispute taking place, as was often the case in the groovy era, and protesters lined the streets in opposition. The protesters had a captive audience with all the commotion in the city and took advantage of it. They garnered a lot of attention for those few days. Along with the protests, anonymous terrorist threats were being called in to law enforcement. This left people wondering if there had been some sort of conspiracy to poison the crowds visiting Philadelphia.

CDC Investigates Legionnaires Disease (en.wikapedia.com)

Authorities thought they may never find the cause of the mystery disease.

Other theories were that Parrot Fever, Venereal Disease or Super Gonorrhea were to blame. Symptoms mimicked all of these illnesses. Food poisoning was also suspected. It wasn’t long before these were also ruled out. The CDC was scrambling to find the cause of this infamous mystery illness.

Before long, many of the Legionnaires that were falling ill were discovered to have stayed at the historic Bellevue Stratford Hotel during the convention. The CDC wasted no time sending out questionnaires to everyone, who was still living, that stayed at the hotel. They were desperate to find some common thread to narrow the search for the cause of the illness. The problem, however, was that everyone that had traveled to the convention was now at home and scattered throughout Pennsylvania, if not other states.

The CDC began compiling information from many sources to help in the investigation.

Interestingly, when the questionnaires began coming in, the CDC discovered that there were incidences of roommates at the hotel where one got sick and the other didn’t. This posed an even more perplexing situation and caused more questions than answers. In addition to that discovery, it was noted that none of the workers at the hotel had come down with the mystery illness.  

1976 Legionnaire’s Funeral (newstalk.com)

Fear of the unknown had people acting in an abundance of caution and many were afraid to attend the funerals of the Legionnaires.

Veterans who lost their lives as a result of Legionnaires Disease had funerals that were not well attended. Since the cause of what seemed to be a possible epidemic was still unknown, many were afraid to go pay their respects for fear of contracting the disease themselves.

Autopsies performed on the deceased were beginning to show some commonalities.

Medical Examiners were finding nickel in the Legionnaires at the time of the autopsy. This was later found to be nickel that had flaked off the scalpels used to perform the procedures. After this discovery, plastic scalpels were used eliminating nickel as a possible source.

To further the investigation, the CDC collected rodent droppings and trash samples and tested the water and air in the hotel. Still, nothing was found. Even more puzzling, people who never stayed at the hotel had fallen ill. People who were in the general area of the hotel, as well as a bus driver who drove a drum corps to Philadelphia for the festivities, died of the disease.

Eventually, all the pieces of the Legionnaires Disease puzzle fell into place.

Legionella Pneumophila Bacterium (watertechonline.com)

Investigators finally got a big break and discovered that the Bellevue Stratford was, in fact, the source of the disease. The hotel’s heating and air conditioning system’s condensation unit wasn’t draining properly and the water runoff had become stagnant and moldy. The bacteria that was found in the stagnant water was new to investigators and later named Legionella Pneumophila. When the system’s fans kicked on, it spewed the bacteria out of the unit causing it to become air born. 

Legionella Bacteria in Cooling Tower (metroforensics.blogspot.com)

Legionnaires Disease was caused by an air born bacteria.

There are a few reasons that so many people were exposed but not all were affected. One reason is that many of the convention participants were Korean War veterans. These men were getting up in age and had compromised immune systems and other health problems. Other’s who were the same age were found to have a certain antibody that fought this strain of bacteria. Additionally, many of the people that worked in the hotel didn’t get sick due to the fact that they were mostly years younger and healthier than the veterans. Although they had been exposed, their bodies successfully fought off the disease.

The CDC has stated that Legionnaires Disease will go down in history as the largest, most frustrating and complicated medical investigations.

In the end, Legionnaires Disease, once known as the mystery disease, left 34 people dead and another 221 people very ill. It was named for the many Legionnaires who fell ill and/or lost their lives because of it. Legionnaires Disease was shown to respond to using a simple antibiotic called Erythromycin. Sadly, that discovery came too late for many.

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Rebeka Knott


Rebeka grew up in the 1960’s & 1970’s and has always subscribed to the theory that a positive attitude will take you far! She is a wife and mother of 3 with a fun-loving spirit, believing that family and relationships are invaluable.