Biologist Ewald Proposes a New Theory of Disease in Plague Time

December 15, 2000
Director of Media Relations

AMHERST, Mass.—Paul Ewald, Domenic J. Paino ’55 Professor in Global Environmental Studies (Biology) at Amherst College, has recently written Plague Time: How Stealth Infections Cause Cancers, Heart Disease, and Other Deadly Ailments ($25, 282 pp., Free Press). Ewald argues that heart disease, cancer and other chronic “modern plagues” are as much the result of viruses and bacteria as of genetics and lifestyle.

Newsweek recently described Paul Ewald as “a bold-minded evolutionist… who has created a whole new framework for thinking about infectious disease.” Ewald’s logic is straightforward: as humans have evolved, the chronic diseases that have troubled us for many generations should have disappeared. But chronic problems such as cancer and heart disease are thriving, not dying out. Ewald concludes that we are now suffering from “plagues of chronic infections” just as people have long suffered from plagues of acute ailments such as cholera and flu.

Plague Time surveys a great deal of contemporary bio-medical research, but perhaps the most representative story that Ewald tells is of peptic ulcers. For years doctors knew of anecdotal evidence that antibiotics helped to cure ulcers, and in the 1980s Australian scientists proved it. Nevertheless, the medical establishment continued to attribute ulcers to stress, genetics or diet, and was often unable to help sufferers. Today ulcers can be treated quickly and efficiently with antibiotics. Infectious causes for liver and cervical cancer, hepatitis B, Lyme disease and other maladies have also been proven recently.

“As we see the scope of infectious causation broadening,” Ewald writes, “not just medicine but society as a whole will change.” He notes the dramatic improvement in health caused by the original germ theory of disease since the 19th century, and predicts that this new theory, “which will reveal the scope of chronic infectious diseases, may have even more far-reaching effects.” Ewald proposes that “people will look at themselves and the human condition differently.” “Though the progressive march of medicine is a common theme in medical texts, the truth is that medical progress has had a bungling sort of advancement,” writes Ewald, and if medicine is to advance further, its practitioners will need more “evolutionary literacy” than they possess today. In contrast to the martial metaphors that have characterized the “war on cancer” and other efforts to “wipe out” disease, Ewald suggests that an evolving pathogen demands an evolving response. We can domesticate the pathogens, Ewald says, just as over generations we responded to the threat of wolves by domesticating dogs.

Plague Time also offers uncommon insights into many medical issues that make headlines: sexually transmitted disease, biological warfare and exotic outbreaks such as Ebola and West Nile virus.




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