Counting virtually every American who died from 1980 to 1992, federal researchers have found that deaths from infectious diseases, formerly on the decline, rose 58 percent over that period, jumping from the fifth- to the third-leading killer.
Although the AIDS epidemic accounts for most of that rise, researchers also documented a “surprising” increase in hard-to-explain respiratory infections among the elderly and blood infections among the young and middle-aged. Even when they excluded AIDS from the analysis, the researchers said the infectious disease death rate had risen 22 percent by 1992, the most recent year for which national records are complete.
“A lot of people expected infectious disease deaths to go away as a public health problem, but this study clearly shows that they’ve gone up,” said the study’s lead author, Dr. Robert W. Pinner of the Centers for Disease Control and Prevention.
The study appears in today’s Journal of the American Medical Association, which contains more than a dozen articles on new or re-emerging infectious diseases. The issue kicks off what the editors call the “first ever” globally coordinated medical publishing venture. This month, 36 journals in 21 countries, from China to Iceland, are calling attention to the apparently growing threats to life and well-being posed by microbes in their respective countries.
Among other findings presented in the AMA journal:
Blood infections with drug-resistant strains of the strep bacteria that cause pneumonia are on the rise, according to a study in Franklin County, Ohio. From 1991 to 1994, the researchers documented that the incidence of invasive strep bacteria more than tripled, from 4 percent to 14 percent.
Underuse of the pneumonia vaccine is imperiling thousands of Americans, researchers say. Although the vaccine is recommended for everyone over 65, for instance, no more than 30 percent of people in that age group receive it, according to the National Center for Health Statistics.
If global warming occurs, malaria, dengue fever, and other tropical or subtropical insect-borne microbial diseases could spread northward, perhaps triggering U.S. epidemics, Johns Hopkins University researchers speculate. “Global climate change can alter the distribution of infectious diseases,” they say, “placing new and potentially large human populations at risk.”
Human immunodeficiency virus, which causes AIDS, is likely to continue mutating, perhaps developing strains that elude conventional screening tests. To address that “major public health concern,” CDC researchers are calling for a new worldwide network of labs to measure subtle changes in HIV’s genetic makeup and invent new tests that screen for unusual strains.
Pinner and his co-workers found that largely because of AIDS, the biggest jump in infectious disease deaths - a more than sixfold increase from 1980 to 1992 - occurred among males 25 to 44. They had five times the death rate of females the same age.
Among the elderly, deaths from underlying infection rose 25 percent over the study period, the researchers say. Some of that increase reflected the growing numbers of old people, Pinner explained, but it also appears that old people are more susceptible to respiratory infections, perhaps because pneumonia bugs have become more virulent and more hardy.
One of the most worrisome trends, he said, was that fatal blood infections rose 83 percent in those 12 years, to 7.7 per 100,000 deaths in 1992. “I don’t think we have good explanations for the increase in the blood-stream infections death rate,” Pinner said.
But not all the new data suggest that the microbes are winning every confrontation. The researchers found no increase in deaths by infection in the 5-to-24-year-old group, and the death rate actually dropped for newborns and toddlers.
And while infectious diseases are now the nation’s third leading cause of death, behind heart disease and cancer, the toll amounted to only 8 percent of the more than 2 million deaths in 1992. The actual consequences of infectious diseases are greater than that figure suggests because many deaths attributed to other causes, such as liver failure, may have been abetted by infection.