On the 24th of July, 1976, a convention held by the American Legion at the Bellevue-Stratford
Hotel in Philadelphia came to an end. Three days later, all over the state, veterans who
had attended the convention started dying. All of them experienced the same symptoms.
Many of them, ultimately, had the same fate. It would take months of patient and painstaking
investigation before doctors would finally be able to identify the cause of this deadly
epidemic. The American Legion was founded in 1919, and
has grown steadily since. The organisation, which consists of and is managed by veterans
of the US armed forces, lobbies on behalf of veterans and provides support and community
for them. It holds an annual convention, as well as many smaller regional gatherings,
and has done so for many years. The 1976 Pennsylvania convention was like
many that had come before it. Around 2,000 veterans from all over the state converged
on the Bellevue-Stratford Hotel in Philadelphia – an iconic hotel and convention centre
that had been used as a venue by the American Legion many times before. It was an opportunity
to meet and catch up with old friends, to discuss the business of the Legion, to hear
speeches and presentations on its activities, and to drink and dine in the company of other
legionnaires. When the convention came to an end on the
24th of July, many veterans returned home feeling happy but tired. Some of them were
unusually tired. Over the next few days many attendees started to feel feverish, and suffered
from chills, aches and pains, and persistent coughs.
The first legionnaire to die with this strange set of symptoms was 61-year-old retired Air
Force Captain Ray Brennan – a man who also worked as a bookkeeper for the Legion. His
death was initially attributed to a heart attack, with doctors only becoming suspicious
when it was followed by several more similar deaths… all of them veterans who had been
at the convention. As time went on, more and more veterans fell
ill. Over the course of just a single month, 149 legionnaires became ill, and 25 passed
away. While some deaths were initially wrongly attributed to heart attacks, it soon emerged
that the actual cause of death in each case was a respiratory infection – one which
resembled a severe form of pneumonia. Doctors all over the state, alarmed by the
sudden outbreak of a mystery disease among their patients, alerted the Center for Disease
Control and the Pennsylvania Health Department, who pooled their resources to try and find
out what was going on. For several months, however, the exact cause of the disease remained
unknown. The hotel quickly became a focus for the investigation.
It was the one common factor – everyone who had been taken ill had been at the hotel.
Even several people who hadn’t been attending the convention had been affected, including
a handful of pedestrians who had merely walked past the property. Several staff were also
affected, including the building’s air conditioning engineer. All signs pointed to the Bellevue-Stratford…
and so the investigation was focussed there. At this time the task force assembled by the
CDC simply didn’t know what they were looking for. Was this mystery disease caused by a
toxin somewhere in the building, or was it an illness that had been passed from person
to person during the convention? They were dealing with something completely unknown,
and so were forced to follow up every possible lead, no matter how unlikely.
Some speculated that the cause of the illness could be cadmium poisoning, spread through
the metal pitchers which were used to serve drinks at the convention. These pitchers were
seized and tested, and this possibility was eliminated. Others suggested that a resident
of the hotel might have smuggled in a secret pet – parakeets were known to carry a disease
that caused the pneumonia-like symptoms that the veterans were experiencing. The hotel
was searched from top to bottom. No parakeets were found.
Throughout the building the carpets were tested, the walls swabbed. Every possible vector for
disease was considered. Had the microphone used by speakers been contaminated? Had it
been spread via the buttons inside elevators? Through a piece of equipment in the kitchens?
Through the hotel’s laundry service, or via an infected member of staff? Was it one
of the Legionnaires who had brought the mysterious disease into the hotel from somewhere else
in the state? The possibilities were endless. With so many leads to chase up, the investigation
went on for months. And to make matters worse, there was relentless media coverage of its
progress. The nation had been on high alert for an epidemic in the weeks and months leading
up to the convention, with experts worried that a new strain of swine flu would soon
be causing havoc across the country. In this atmosphere of fear and tension, it’s no
wonder than everyone was keen to discover the cause behind the mystery illness. In the
absence of any progress towards a definitive answer, though, many began speculating. It
was proposed that the disease was the result of everything from a terrorist attack, to
an alien invasion, to a series of chronically malfunctioning photocopiers.
Of course, none of these wild ideas turned out to be correct.
Months passed, and despite much speculation in the papers, the CDC task force was none
the wiser. By this stage the investigation had dragged on so long that CDC disease specialist
Dr Joseph McDade was openly lambasted at a Christmas party by one of his superiors for
not having made any progress in the search for a cause.
Stung by this public criticism, Dr McDade returned to his lab as soon as possible and
set to work injecting lung tissue samples from stricken veterans into guinea pigs. After
a few weeks of intensive work, he noticed something: a new and unknown bacteria present
in the livers of these guinea pigs. It would require a great deal more testing before he
realised that he had finally laid eyes on the cause of the epidemic. This bacteria,
previously undiscovered, would eventually come to be known as Legionella pneumophila.
Once it had been discovered, naming the bacteria and the disease it caused was an easy job.
With no idea what was causing so much death and illness amongst members of the American
Legion, investigators had already started referring to it as “Legionnaire’s Disease”.
The name stuck. With the cause of the disease now positively
identified, the CDC were able to further their investigations. They traced the bacteria to
the cooling tower of the hotel’s air conditioning system, where the disease was breeding freely
in standing water which had collected there. This was how it had been spread during the
convention. Over a few hot days in July the air con system had sprayed a deadly load of
bacteria into many areas in and around the hotel.
The discovery of legionella solved the mystery not just of what had happened at the 1976
American Legion convention, but also what had been behind several other smaller mystery
illness outbreaks which had taken place in previous years. Investigators were able to
look back through recent history and note several incidents of mass illness attributable
to the bacteria, including at least one other at the Bellevue-Stratford hotel.
To combat this newly recognised danger, new regulations were introduced governing the
maintenance of air conditioning systems – with these standards quickly spreading worldwide.
At the same time doctors set to work researching treatments for the newly-identified disease.
Now, many years later, Legionnaire’s Disease is still a danger that we face. Several outbreaks
happen each year in the US alone, spreading via air conditioning units, swimming pools,
spas or other places where large bodies of water are found. Fortunately, we have a much
better understanding of the bacteria than we did in 1976, along with an arsenal of means
for controlling it. Systems which are susceptible to legionella are now routinely monitored,
and include elements for treating water to destroy the bacteria.
Additionally, when an outbreak does occur, diagnosis is generally swift, and the infection
can in many cases be treated with a course of antibiotics. Through painstaking research
and learning, we have turned what was once a terrifying mystery disease into something
much less deadly. Now it is merely something that, while it does still have an impact,
can be kept in check with diligent care and close attention. Never again will this disease
cause the kind of fear and speculation that it did back in 1976.