From the February 2005 Scientific American Magazine
An Endangered Species in the Stomach ( Preview )
Is the decline of Helicobacter pylori, a bacterium living in the human stomach since time immemorial, good or bad for public health?
By Martin J. Blaser
Just as scientists were learning the importance of H. pylori, however, they discovered that the bacteria are losing their foothold in the human digestive tract. Whereas nearly all adults in the developing world still carry the organism, its prevalence is much lower in developed countries such as the U.S. Epidemiologists believe that H. pylori has been disappearing from developed nations for the past 100 years thanks to improved hygiene, which blocks the transmission of the bacteria, and to the widespread use of antibiotics. As H. pylori has retreated, the rates of peptic ulcers and stomach cancer have dropped. But at the same time, diseases of the esophagus–including acid reflux disease and a particularly deadly type of esophageal cancer–have increased dramatically, and a wide body of evidence indicates that the rise of these illnesses is also related to the disappearance of H. pylori.