In 1967 the surgeon general of the United States delivered a
speech to Congress: "It is time to close the book on infectious diseases,"
he said. "The war against pestilence is over."
In 1998 Surgeon General David Satcher had a different message.
The Miami Herald reported his speech with this headline: "Infectious
Diseases a Rising Peril; Death Rates in U.S. Up 58% Since 1980."
The middle of the last century was a time of great confidence in
science and medicine. With the introduction of antibiotics in the 1940s,
and a lengthening list of vaccines that prevented the most frightening
diseases, Americans felt that it was only a matter of time before diseases
caused by microorganisms (i.e., infectious diseases) would be
completely manageable. The nation’s attention turned to the so-called
chronic diseases, such as heart disease, cancer, and stroke.
So what happened to change the optimism of the 1960s to the
warning expressed in the speech from 1998? Dr. Satcher explained it
this way: "Organisms changed and people changed." First, we are
becoming more susceptible to infectious disease precisely because
of advances in medicine. People are living longer. Sicker people are
staying alive much longer than in the past. Older and sicker people
have heightened susceptibility to what we might call garden-variety
microbes. Second, the population has become more mobile. Travelers
can crisscross the globe in a matter of hours, taking their microbes
with them and introducing them into new "naive" populations.
Third, there are growing numbers of microbes that truly are new (or at
least, new to us). The conditions they cause are called emerging diseases.
Changes in agricultural practices and encroachment of humans
on wild habitats are just two probable causes of emerging diseases.
Fourth, microorganisms have demonstrated their formidable
capacity to respond and adapt to our attempts to control them, most
spectacularly by becoming resistant to the effects of our miracle
drugs.
And there's one more thing: Evidence is mounting that many conditions
formerly thought to be caused by genetics or life-style, such as
heart disease and cancer, can often be at least partially caused by microorganisms.
Microbes never stop surprising us—in their ability to harm but
also to help us. The best way to keep up is to learn as much as you can
about them. This book is a good place to start.
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