For a small fraction of those who are infected, the consequences can be deadly. The microbe has been linked to stomach, or gastric, cancer, a leading killer worldwide. This is a cancer of white blood cells found near the stomach lining. In 1994, the World Health Organization classified the bacterium as a carcinogen. In the United States each year, some 7 million people suffer H. pylori -related disease, including ulcers, and thousands die, primarily from gastric cancer.
Antibiotics can cure ulcers, and even some cases of the lymphoma.
In 1995, the Digestive Health Initiative, organized by the American Gastroenterological Association and other organizations, launched a campaign to convince consumers and physicians that people having ulcer symptoms should be tested for H. pylori . Since then, according to the initiative, the proportion of physicians ready to treat H. pylori has risen dramatically. Just as gastroenterologists are beginning to smell success in their quest to eliminate the ulcer-causing microbe, however, an investigator who has studied H. pylori for many years is trying to convince researchers and physicians that the elimination of the microbe may not be such a good idea. Martin Blaser of Vanderbilt University in Nashville says that the bacterium's presumed long acquaintance with mankind may offer benefits. His preliminary evidence suggests that people who aren't infected with H. pylori are more likely to develop reflux a painful disease in which acid from the stomach backs through a leaky valve and inflames the esophagus.