AQUATIDE

In July 1976, more than 4000 World War II Legionnaires, along with their families and friends, have assembled in Philadelphia to participate in the 58th American Legion's convention of which 600 are staying at the Bellevue Stratford Hotel where the convention is hosted.

One day after the opening of the convention, some of the participants are taken ill, all have similar symptoms: Fever, coughing and breathing difficulties - all of which are dismissed as the celebration carries on at full swing.

On Tuesday 27th July, four days after the convention started, things begin to turn sour, man dies at hospital, that of an Air Force veteran who attended the Philadelphia convention.

For no explicable reason, the American Legionnaires start dying, one by one, of a mysterious illness...

48 hours after initial outbreak the first tissue specimens analysed by CDC (Centres for Disease Control) ruled out; Typhoid, Lassa and Marburg Virus, Pertussis and the Plague. After 5 days, the CDC had eliminated; Herpes, Mumps, Measles and Influenza. Blood tests also confirmed it was NOT Super Gonorrhoea. Swine Flu & Parrot Fever tests were also negative.

The crisis was going from bad to worse, the infection rate was still rising, death rate still rising. The CDC could still not identify the killer. Questionnaires' were sent out to all who had become ill. Most puzzling was that some Legionnaires’ developed the disease, some not. Looking at the data revealed the highest number of infected people were those registered at the Bellevue Stratford Hotel. Even though some were not registered at the hotel, or ever been inside, they had walked along the street of the hotel. The CDC Found that the longer people had spent along the sidewalk the more chance they had of becoming sick.

The death toll was still mounting, now 27 people dead! Over 200 hospitalised! The CDC still had no idea what was causing it, or how it was being spread though they were convinced the outbreak had something to do with the Bellevue Stratford hotel.

On the 28th December 1976 Joseph McDade, research microbiologist at the CDC, viewed guinea pig slides, like he had done so many times before, and noticed something he had not seen before, a cluster of the bacteria that were engulfed by a white cell. This was a major breakthrough, the bacterium had been found.

147 days after the initial outbreak which killed 34 people, hospitalised 221 others, the legionnaires’ disease bacterium was discovered, a suitable antibiotic was also produced. On the 19th November 1978 the disease was officially called LEGIONELLA PNEUMOPHILA.

Questions did still remain......

Where did it come from?
How was it spread?

Researchers quickly discovered its properties.

Naturally occurring bacterium often found in water sources such as rivers and lakes.
They knew it liked warm water, travelled through the air as mist.
Water temperatures in the range of 20C to 45C seem to favour growth.
The organism does not appear to multiply below 20C and cannot survive above 60C.
May remain dormant in cool water and only multiply when water temperatures reach a suitable level.
Legionella bacteria requires a supply of nutrients to multiply, sources may include organisms already present in water such as algae and amoebae.
The presence of sediment, rust and sludge also play an important role in harbouring and providing favourable conditions in which Legionella may grow.
Bio-film on the water surface can protect Legionella from temperatures that would normally kill the organism.
Disease contracted by inhaling the Legionella bacteria, usually in aerosols.

No evidence to suggest it can be contracted through human contact.