The gnawing pain of a stomach ulcer affects about a tenth of Americans at some point in their lives. The culprit, researchers now know, is not stress but a corkscrew-shaped bacterium called Helicobacter pylori. When the bug infects the stomach lining, it provokes a persistent immune response that can lead to ulcers and stomach cancer. One thing that isn’t clear, though, is how the infection is transmitted. Researchers at MIT have recently raised the disturbing possibility that H. pylori may spread through water supplies--at least in one region of Colombia where infection is almost universal.
H. pylori is rife everywhere; one person in two harbors the bug, which probably makes it the world’s most common infection. In 1982, Australian gastroenterologist Barry Marshall was the first to suggest that H. pylori caused stomach disorders. To prove his point, Marshall drank a bug-filled solution and made himself sick to his stomach. At ...