A Field Guide to Germs by Wayne Biddle

Author:Wayne Biddle [Biddle, Wayne]
Language: eng
Format: epub
ISBN: 978-0-345-80463-1
Publisher: Knopf Doubleday Publishing Group
Published: 2012-09-11T16:00:00+00:00

• Legionella •

Some diseases are said to have hastened the decline of empires, but only one is famous for putting a hotel out of business. In July 1976, an American Legion convention in Philadelphia’s venerable Bellevue-Stratford Hotel set the stage for the discovery of a new genus of pathogenic bacteria. Later named Legionella, the bugs had found lodging inside 221 people who had come for the revelries or simply frequented the hotel. Thirty-four died subsequently from acute pneumonia. Understandably, the Bellevue-Stratford lost its charm and folded within a year.

Of course, Legionella was new only in the sense that humans had not been scientifically aware of it before. After five months of desperate detective work led to its identification, researchers took out old blood samples from previous mystery cases and verified that the same organism had caused similar outbreaks in a Washington, D.C., hospital in 1965 and a Pontiac, Michigan, health department office in 1968 (thereby proving, among other things, that germs are not afraid of medical facilities). They even thawed out a guinea pig from 1947 that had been injected with blood from a patient who died from something untraceable at the time and found Legionella. “Legionnaire’s disease” has probably been behind thousands of deaths from pneumonia every year in the United States for a long time, especially since air conditioning became part of urban life and perhaps since the unwashed masses accepted indoor plumbing. Between 8,000 and 18,000 Americans get it annually, with a fatality rate ranging between 5 and 30 percent.

The culprit in Philadelphia was specifically L. pneumophila, one of some forty-three Legionella species now known to exist around the world, at least nineteen of which cause pneumonia in humans. L. pneumophila and its brethren like to live in environments akin to puddle scum—wet, dark, and kind of rotty. At the decidedly un-rotty Bellevue-Stratford, air-conditioner cooling towers on the roof provided a conducive summertime abode, from which the germs circulated throughout the edifice in a fine infectious mist. But Legionella bacteria have also been found in showerheads and faucet pipes. L. pneumophila can survive in room temperature tap water for more than a year. Streams, ponds, and plain old mud may harbor them. Hot tubs, humidifiers, vegetable stand misters, decorative fountains—the list of possible habitats is unsettling. Chlorination may not remove the threat if the concentration of organisms is high.

Once a person becomes infected by inhaling enough bacteria, two courses of disease (properly known as legionellosis) may occur, depending on such factors as the victim’s age, use of cigarettes or alcohol, and other conditions that are still unclear. Legionnaire’s disease, the more serious, strikes 5 percent or fewer of people exposed to Legionella, takes two to fourteen days to develop, and kills up to 40 percent of its victims. The comparatively mild Pontiac fever shows many of the same symptoms (high fever, chills, headache, cough) but does not include pneumonia, hits 90 percent of those exposed, comes on in just one to two days, and may be debilitating for a week or so but is not fatal.

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