Threats to the health of the world's citizens from re-emerging and enduring infectious diseases and the certainty that new, harmful microbes will emerge underscore the importance of continued support of basic biomedical research, says John La Montagne, Ph.D., of the National Institute of Allergy and Infectious Diseases (NIAID).
Malicious microbes, the illnesses they cause and NIAID's research programs to combat them are among the topics that Dr. La Montagne plans to discuss Feb. 21, at the annual meeting of the American Association for the Advancement of Science in Atlanta, Ga. Dr. La Montagne directs the Division of Microbiology and Infectious Diseases at NIAID, part of the National Institutes of Health, which is the federal focal point for biomedical research.
Modern science has succeeded in controlling many infectious diseases through the development of highly effective drugs and vaccines that have prevented, for example, most once-common childhood infections," says Dr. La Montagne. "This success led to the perception that infectious diseases were no longer major problems.
However, during the last 15 years several events--among them, the global emergence of HIV/AIDS and multiple drug-resistant pathogens--shattered this illusion and firmly established that infectious diseases are not static, but dynamic problems that will continue to pose public health threats and constantly challenge the scientific community," he continues. "Their human and economic tolls are an important impetus for us to improve the detection, treatment and prevention of these illnesses, and this requires a continued commitment to research."
The institute's programs include support for laboratory and applied research on the environmental influences, microbial adaptations and organism interactions that influence emerging microbes. NIAID also provides funds for the development and testing of control strategies, including vaccine development. Together with the Centers for Disease Control and Prevention (CDC), the institute supports detection of and quick scientific responses to outbreaks of diseases.
New and re-emerging microbes are those that are recently identified, causing more disease in humans or threatening to spread to new areas in the near future. While HIV, recognized just 15 years ago, is the most dramatic example of a new pathogen, other viruses, bacteria, fungi and illnesses have emerged to menace humans, such as Legionnaire's disease, Lyme disease, toxic shock syndrome and drug-resistant strains of common bacteria, including those that cause tuberculosis. Among the newest microbes is a new cholera bacteria strain, O139, that emerged in Southeast Asia in 1992 and affected more than 500,000 people. In the United States, the emergence of hantavirus has caused 98 cases of hantavirus pulmonary syndrome in 21 states since June 1993.
New microbes develop or old pathogens re-emerge for many reasons, Dr. La Montagne explains. "Microbes have the capacity to reinvent themselves. Compared to people, viruses and bacteria have very little genetic material and one mutation can change a microbe's ability to infect, spread or cause disease," he says. "Also, microbes can transform themselves rapidly because they exist in large numbers and quickly reproduce."
Additionally, climate changes, new housing patterns and regional and international trade contribute to disease development. For example, new communities built in reforested areas of the northeastern United States have increased the contact between people and the ticks that carry the Lyme disease bacteria.
Public health failures or changes can foster disease, as well, Dr. La Montagne notes. The inadequate quality control of handling and preparing raw foods have led to life-threatening illnesses caused by a virulent strain of the bacterium E. coli in several states. In Milwaukee, Wis., 400,000 people became ill in 1993, from water contaminated with Cryptosporidium.
Further problems stem from the extensive and inappropriate use of antibiotics, including broad-spectrum drugs that kill many species of bacteria at once. These health care patterns, along with the lack of adherence to the full therapeutic regimen, have led to the development of drug-resistant bacteria, several of which may soon be untreatable with current drugs, Dr. La Montagne notes.