Health officials worldwide are struggling to understand the latest outbreaks of diseases once thought to be on the wane and to mobilize resources to do battle with these ancient killers, called infectious and parasitic diseases.
Among this class of diseases are such familiar diseases as malaria, tuberculosis, and cholera as well as more exotic ones such as dengue hemorrhagic fever, Ebola, and Chagas' disease.
"These diseases are a major cause of death and disability in low-income countries and are re-emerging as a serious health problem in developing countries," said Dr. Bruce Carnes, one of the authors of a new 52-page Population Bulletin from the Population Reference Bureau, "Infectious Diseases: New and Ancient Threats to World Health."
One such disease, smallpox, was eradicated in the 1970s. That achievement led many health experts to believe that other infectious and parasitic diseases would one day be completely eradicated, the report notes, adding that developments since then have shattered that belief.
In recent years, newspaper accounts of terrifying outbreaks of Ebola, dengue hemorrhagic fever, Hantaan viruses, cholera, and other exotic diseases have captivated the public and generated best-selling books like "The Hot Zone" and the hit movie "Outbreak."
"Unfortunately," Carnes said, "the threat posed by these diseases is not fiction. They have been responsible for more deaths throughout history than any other cause, including old age. And they still are."
Carnes, a biologist, heads research into aging and demography at Argonne National Laboratory's Center for Mechanistic Biology and Biotechnology near Chicago. Other authors of the Population Reference Bureau report are biodemographer S. Jay Olshansky of the University of Chicago, sociologist Richard G. Rogers of the University of Colorado, and epidemiologist Len Smith of the Australian National University.
The team of scientists points out in the report that infectious and parasitic diseases are not disappearing. The HIV/AIDS epidemic alerted health officials to the fact that these diseases had been on the rise for the past quarter-century. Old diseases are appearing with increasing frequency, new forms of old diseases that resist treatment are appearing in increasing numbers, and new diseases rarely or never before experienced by humans are surfacing.
More than 28 new disease-causing microbes have been identified since 1973, the report notes. These include a new strain of cholera that has killed thousands of people in Africa and Asia and new forms of tuberculosis and meningitis that are resistant to most known antibiotics. Outbreaks of such deadly diseases as diphtheria, Hantaan virus, bubonic plague, tuberculosis, malaria, cholera, meningitis, and Ebola have been reported recently.
The death toll is high. More than 17 million people died from these diseases in 1995, accounting for more than one-fourth of all deaths. About 97 percent of deaths from these diseases occur in low-income countries. The vast majority of these deaths, the authors said, could have been avoided.
They added that the mortality and health problems these diseases cause retard social and economic development in low-income countries, perpetuating the poverty, poor health, and squalid living conditions that contribute to the spread of these diseases.
The developed nations are no longer safe from these diseases, the report says. The diseases can travel in a matter of hours to any part of the globe, thanks to modern air travel. In addition, the United States records 600,000 cases of pneumonia each year, resulting in 25,000 to 50,000 deaths, and between 10,000 and 40,000 deaths due to influenza. The new states of the former Soviet Union experienced an epidemic of diphtheria in 1990, with more than 40,000 cases reported in 1994.
A host of natural and human actions influence the introduction and spread of these diseases, the authors contend. Among them are certain agricultural developments and practices, urbanization, migration and travel, and natural disasters. The authors note that otherwise beneficial developments such as medical advances also can provide new ways for infectious agents to jump from person to person. They add that overuse and misuse of antibiotics have led to resistant strains of bacteria.
Carnes and his fellow authors believe that public health experts and policymakers can collaborate to respond to the increase in infectious parasitic disease cases. They call for:
Strengthening infection control precautions. Ensuring appropriate laboratory-based surveillance of diseases resistant to available drugs. Developing more rapid diagnostic tests. Instituting surveillance of the use of antibiotics or other antimicrobial agents. Improving physician prescribing practices. Encouraging pharmaceutical companies to develop new antimicrobial agents. Developing new or improved vaccines and effective means to distribute them throughout the world. Educating the public about appropriate antimicrobial agent use and the dangers of inappropriate use. Copies of "Infectious Diseases: New and Ancient Threats to World Health" may be purchased for $8.50 (price includes postage) from the Population Reference Bureau by calling 1-800-877-9881 or 202-483-1100.
Founded in 1929, the Population Reference Bureau is a private, nonprofit organization dedicated to the dissemination of timely and objective information on population trends.
With more than 200 major research programs, Argonne National Laboratory is operated by the University of Chicago as part of the U.S. Department of Energy national laboratory system.
Materials provided by Argonne National Laboratory. Note: Content may be edited for style and length.
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