NEHA's position on emerging infectious diseases.
Background and General Discussion
Emerging infectious diseases, which are defined as infections that have newly appeared in a population or have existed but are rapidly increasing in incidence or geographic range, are currently the leading cause of death worldwide (1-3). Complacency about infectious diseases in the United States has been misplaced. According to Margaret Hamburg, Commissioner of the New York City Department of Health, considering domestic and international diseases as separate entities is an outmoded concept since many conditions that contribute to disease emergence or reemergence in the developing world are also present in the United States (4). For example, in 1993, contamination of the municipal water supply in Milwaukee, Wisconsin, resulted in an outbreak of cryptosporidiosis that affected an estimated 400,000 people; approximately 4,400 persons required hospitalization (5). It should be noted that similar problems with water purification systems have been found in other U.S. cities (6). One of the six main re-emerging diseases, as identified by the World Health Organization, tuberculosis, has reemerged in the United States after decades of decline (7,8).
The purpose of this position paper is to review current information on the status of emerging infectious diseases with particular emphasis on the implications for environmental and public health. This document should serve as a basis for initiating proactive discussions on the topic among environmental and public health practitioners and colleagues in related fields with policy makers at all levels - local, state, national, and world-wide. In addition, it is intended to be used for the purpose of educating both the public and policy makers about the serious issue of emerging pathogens.
According to Morse (3,9), most emerging infectious diseases (Table 1) appear to be caused by pathogens already present in the environment that have been given a selective advantage by changing conditions. For example, there are many infections originating as zoonoses (10,11) suggesting that the "zoonotic pool" - introductions of infections from other species - is an important and potentially rich source of emerging diseases. Therefore, certain basic concepts in disease emergence, as put forth by Wilson (12,13), must be considered. These concepts are:
* emergence of infectious diseases is complex
* infectious diseases are dynamic
* most new infections are not caused by genuinely new pathogens
* agents involved in new and reemergent infections cross taxonomic lines to include viruses, bacteria, fungi, protozoa, and helminths
* the concept of the microbe as the cause of disease is inadequate and incomplete
* human activities are the most potent factors driving disease emergence
* social, economic, political, climatic, technologic, and environmental factors shape disease patterns and influence emergence
* understanding and responding to disease emergence require a global perspective, conceptually and geographically
* the current global situation favors disease emergence
Specific factors, such as ecological, environmental, or demographic factors, precipitating disease emergence can be identified in virtually all cases and are increasing in prevalence (1,14-17). Recently the World Health Organization listed several of these factors for new and re-emerging diseases, including:
* changes in lifestyle, including over-crowded cities where population growth has out-paced supplies of clean water and adequate housing
* dramatic increases in national and international travel, whereby an individual traveler may be infected in one country and spread the disease to others before falling ill
* deterioration of traditional public health activities such as surveillance and diagnostic laboratories needed to quickly recognize emerging problems
* complacency, despite numerous warnings in recent years
Interestingly, the National Academy of Science's Institute of Medicine has also identified erosion of the public health infrastructure among the factors contributing to new and reemerging infectious diseases (18). Classical environmental and public health measures have long served to minimize dissemination and human exposure to many pathogens spread by traditional routes such as water or preventable by vector control (1). It should be noted, however, that upon breakdown in preventive measures the pathogens, which, as previously noted, often remain in the environment, are sometimes able to take advantage of the opportunity to reemerge. Limited financial and human resources and competing priorities have resulted in a "crisis mentality" with emphasis on implementing so-called emergency control methods in response to epidemics rather than on developing programs to prevent epidemic transmission (19).
In 1995, the National Environmental Health Association (NEHA) released a position statement on health care reform which stated, "Highly publicized epidemics of waterborne and food-borne illness have occurred recently, with substantial morbidity and associated cost. Such epidemics were due in part to inadequate systems of early detection and insufficient environmental protection, which in turn were caused by the divestiture of public health programs to nonpublic health agencies and by years of financial neglect.... Regardless of federal reform, state and local governments should emphasize prevention first.... Public and environmental health programs are established by law to protect the health of the entire community [and] should be seen as the crucial population-based practice in which the scientific base for defining problems, developing interventions, and measuring results is epidemiology. Thus, then [other health services] become active after the failure of the public health system. Thus the stronger the public and environmental health system, the less need for [these other, more costly, services]" (20).
With the recent demise of many environmental and public health programs, the existing capacity of the public and environmental health infrastructure at the local, state, national, and international level to respond to these challenges is limited. Human resource, equipment, and facility needs must be identified and addressed. Training needs of environmental and public health professionals, as well as medical students, clinicians, epidemiologists, microbiologists, entomologists, mammalogists, behavioral scientists, and other researchers, must also be identified and addressed. Additional emphasis should be given to the critical importance of communicating guidelines for disease prevention; the need for educating the public and policy makers about the importance of these issues; the need for strengthening existing partnerships and developing new ones; and the need to carefully identify priorities. New technologies, such as the proposed use of the National Aeronautics and Space Administration's scientific and technologic capabilities for detecting, monitoring, and improving the control of insect-borne diseases (21), should be identified and explored to the fullest extent possible.
1. Morse, S.S. (1995), "Factors in the Emergence of Infectious Diseases," Emerging Infectious Diseases, 1:7-15.
2. Morse, S.S., and A. Schluederberg (1990), "Emerging Viruses: the Evolution of Viruses and Viral Diseases," J. Infect. Dis., 162:1-7.
3. Morse, S.S. (1993), "Examining the Origins of Emerging Viruses," Emerging viruses, ed. S.S. Morse, Oxford University Press, NY, pp. 10-28.
4. Hamburg, M. (June 1995), Remarks at the Conference on Emerging Infectious Diseases: Meeting the Challenge, NY.
5. MacKenzie, W.R., N.J. Hoxie, M.E. Proctor, et al. (1994), "A Massive Outbreak in Milwaukee of Cryptosporidium Infection Transmitted Through the Public Water Supply," N. Engl. J. Med, 331:161-7.
6. Centers for Disease Control and Prevention (December 1993). "Assessment of Inadequately Filtered Public Drinking Water - Washington, D.C.," MMWR, 43:661-3.
7. Centers for Disease Control and Prevention (1993), "Expanded Tuberculosis Surveillance and TuBerculosis Morbidity - United States, 1993," MMWR, 43:361-6.
8. Centers for Disease Control and Prevention (1994), "Multi-drug-resistant Tuberculosis in a Hospital - Jersey City, New Jersey, 1990-1992," MMWR, 43:417-9.
9. Morse, S.S. (1991), "Emerging Viruses: Defining the Rules for Vital Traffic," Perspect. Biol. Med., 34:387-409.
10. Fiennes, R.W. (1978), Zoonoses and the Origins and Ecology of Human Disease, Academic Press, London.
11. McNeill, W.H. (1976), Plagues and Peoples, Anchor Press/Doubleday, NY.
12. Wilson, M.E. (1995), "Travel and the Emergence of Injections Diseases," Emerging Infectious Diseases, 2:39-46.
13. Wilson, M.E. (1994), "Disease in Evolution: Introduction," Disease in Evolution: Global Changes and Emergence of Infectious Diseases, ed. M.E. Wilson, R. Levins, and A. Spielman, New York Academy of Sciences, NY, 740:1-12.
14. Mahon, B.E., D.D. Rohn, S.R. Pack, and R.V. Tauxe (1995), "Electronic Communication Facilitates Investigation of a Highly Dispersed Foodborne Outbreak: Salmonella on the Superhighway," Emerging Infectious Diseases, 1:94-5
15. Tauxe, R.V. (1991), "Salmonella: a Postmodern Pathogen," J. Food Protection, 54:563-8.
16. Hedberg, C.W., K.L. MacDonald, and M.T. Osterholm (1994), "Changing Epidemiology of Food-borne Disease: A Minnesota Perspective," Clin. Infect. Dis., 18:671-82.
17. Hedberg, C.W., W.C. Levine, K.E. White, R.H. Carlson, D.K. Winsor, D.N. Cameron, et al. (1992), "An International Food-borne Outbreak of Shigellosis Associated with a Commercial Airline," JAMA, 268:3208-12.
18. Institute of Medicine (1988), The Future of Public Health, National Academy Press, Washington, D.C.
19. Gubler, D.J., and G.G. Clark (1995), "Dengue/Dengue Hemorrhagic Fever: The Emergence of a Global Health Problem, Emerging Infectious Diseases, 1:55-7.
20. National Environmental Health Association (June 1995), Position on Health Care Reform, Denver, Co.
21. Braukus, M., and R. Khanna (1966), "NASA Sponsors Symposium on Remote Sensing and Control of Insect-transmitted Diseases, Emerging Infectious Diseases, 2:74.
22. Satcher, D. (1995), "Emerging Infections: Getting Ahead of the Curve," Emerging Infectious Diseases, 1:1-6.
[TABULAR DATA FOR TABLE 1 OMITTED]
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|Title Annotation:||National Environmental Health Assn.|
|Publication:||Journal of Environmental Health|
|Date:||Oct 1, 1996|
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