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Conservation Medicing:
An Emerging Field

Mark Pokras*
Gary Tabor*
Mary Pearl†
David Sherman*
Paul Epstein‡
*Tufts University School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536
†Wildlife Preservation Trust International, 520 Locust Street, Suite 704, Philadelphia, PA 19102
‡Center for Health and the Global Environment, Harvard Medical School, 260 Longwood Avenue, Boston, MA 02115

The loss of biodiversity—the entire wealth of plant and animal species—is perhaps the most important problem that faces our fragile planet. Unwittingly and unremittingly, our species is in the process of bringing about an unprecedented biological disaster. In the wake of our growth and development lie hundreds of thousands of extinct species that are gone forever. The process of extinction continues, and today even larger numbers of species are threatened. Such losses undermine the ecological fabric that sustains the web of life, including human life. Ironically, this massive wave of species extinctions is foreclosing the discovery of new medicines and remedies from natural sources. Society has seemed illequipped to deal with these health crises, because we lack professionals who have the interdisciplinary skills to link the health issues of ecosystems, animals, and humans.

The health and well-being of people and other animals are threatened by the effects of humans on ecosystems, including the large-scale alteration and destruction of habitat, the decline and extinction of species, the alteration of ecological processes, the invasion of nonnative (alien) species, the continued economic emphasis on short-term bottom-line thinking, and the spread of contaminants and hazardous substances through all levels of the food chain. Animal health and human health are inextricably connected through the ecological realities that govern life on our planet.

The health of individuals, species, and populations and the more encompassing notion of environmental health represent a continuum of the way in which health concerns currently are defined. At all levels, the complexity of health

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issues is being revealed. The landscape of understanding includes a greater awareness of the synergism of cumulative effects and multiple stresses. As the scientific ability to study environmental perturbations and ecosystem dynamics improves, new patterns of disease transmission and alarming health effects are emerging.

What is Conservation Medicine?

The term conservation medicine was first introduced by Koch (1996) to mean the study of the broad ecological contexts of health. It tries to relate concerns about the health of all living organisms to the integrity of ecosystems. The overlap of veterinary medicine, human medicine, and conservation biology forms the knowledge base for this field.

The field of veterinary medicine long has been recognized for its comparative approach. Until recently, it primarily addressed the health and productivity of animals owned by people. But veterinarians increasingly are concerned with turning their skills to the health of wild animals and their habitats. Physicians also are recognizing that conservation of biodiversity is important, to protect species that provide a buffer against the emergence of pests and pathogens and that serve as potential medical models of and environmental sentinels for human health. Conservation biologists are working with veterinarians and physicians to expand beyond conventional paradigms of health and examine human and animal health through an ecological lens. By bringing the three disciplines together, new areas of research, education, policy, and training can be engaged. In short, solutions to future concerns about environmental health will be related to the development of effective interdisciplinary tools and modes of problem-solving.

Conserving the integrity of the biosphere is the applied goal of conservation medicine. It attempts to provide a cognitive framework for examining health functions within ecosystems. As health problems related to environmental degradation multiply and magnify in importance, health professionals increasingly will be relied on to comment on environmental strategies and to advise communities taking part in processes of environmental decision-making. In their publicly perceived roles as educators, all conservationists need to understand and articulate the linkage between human and animal health and intact ecosystems. Ultimately, as concerned citizens of the world, we must work together to define the appropriate balance between the needs of people, domestic animals, and wildlife in the face of finite amounts of energy, land, and other resources.

Some Current Challenges:
Interfaces Between Medicine and Conservation

Emerging and Re-Emerging Diseases

The influence of parasites and disease on human health and demographics rarely is questioned. Such recent books as The Coming Plagues (Garrett 1994) and such classics as Rats, Lice, and History (Zinsser 1963) have reflected our all-too-

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human interest in health threats that directly affect us and those close to us. Historically, conservationists and wildlife professionals have ignored or downplayed the effects of these same pressures on wildlife populations and natural systems until species became endangered.

However, as Garrett (1994) points out so eloquently, ecological perturbations are fast bringing down the barriers that once limited human-to-animal disease transmission. New variants of the cholera-causing organism, Vibrio cholerae, have been found moving in intercontinental patterns within marine algal blooms that are associated with red-tide phenomena and the periodic occurrence of El Niño—southern oscillation events (Epstein 1993). Strains of Hantavirus that have fatality rates of nearly 55% in humans have emerged in regions that exhibit disturbances of habitat and climate (Epstein 1995). Outbreaks of Pfiesteria piscida, a toxic dinoflagellate, in the Chesapeake Bay of Maryland recently have created headlines. Blooms of Pfiesteria associated with large-scale fish kills and disease in both people and animals have been linked to nutrient-rich agricultural runoff (Anonymous 1997; Barker 1997; Steidinger and others 1996).

In those instances, alarm has arisen because of concern for human health. The effects of the pathogens on populations of domestic or wild animals and natural ecosystems are poorly understood, but there are many examples in which health effects of human activities on animal populations are understood more clearly (Dobson and May 1982; Thorne and Williams 1988). For instance, the introduction of tuberculosis from humans to populations of orangutans and other endangered primates has serious implications for the long-term existence of these species in the wild (Jones 1982). Predators and diseases, plus disease vectors and reservoirs that people have introduced either purposefully or accidentally, have led to the extinction of many endemic Hawaiian bird species, and they threaten many more (van Riper and other 1986).

Chronic Toxic Pollutants

In parallel with the growing awareness of emerging infectious diseases, concerns about the effects of chronic exposure to toxic chemicals have surfaced as well (Colburn and others 1996). Bioaccumulation of selenium from agricultural runoff in the western United States has caused large-scale fish mortality, deformity and death in fish-eating birds and mammals, and the closure of some protected federal wildlife refuges (Botkin and Keller 1997). Endocrine-disrupting chemicals are suspected of producing widespread effects on the reproductive systems of fish, reptiles and amphibians, birds, and mammals, including humans (Colborn and Clement 1992). The bioaccumulation of persistent and widespread toxic substances may have effects that range from congenital defects to promotion of cancer, reproductive diseases, and increased susceptibility to disease (for example, immunological dysfunctions) (Botkin and Keller 1997; Colborn and Clement 1992; Colborn and others 1996). Although the precise mechanistic relationships between the biological activities of these toxic substances and disease are not understood completely, the trend is disturbing and underscores the need to examine the persistence of chemicals within the environment in an entirely new light.

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Compromised Health of Ecosystems

At another level, the health of ecosystems is threatened by increased fragmentation of habitat, decreased ecological resilience, unbalanced proportions of predators and prey, introductions of alien species, changes in global climate, enhanced ultraviolet radiation, and the multitrophic-cascade effects related to disturbance and extinction (Carpenter and Kitchell 1993; Epstein 1993; Hollings 1996; Kreuss and Tscharntke 1994; Malcolm and Markham 1996). The integrity of ecosystems and the species they comprise is being undermined daily by incremental catastrophes.

Interdisciplinary Barriers.

Each discipline approaches problem-solving from its own perspective and with its own set of inherent biases. Both medical and conservation professionals need to adopt new attitudes if truly creative interdisciplinary problem-solving is to occur. When asked what physicians and veterinarians needed to learn to play a more constructive role in conservation, one wildlife biologist recently remarked, “They should learn to leave their white coats and attitudes at home!” (A. Major, USFWS, pers. comm.). Clearly, we need to get to know each other better. A mutual respect for the knowledge and abilities of other professionals is an important prerequisite to progress.

The Goals of Conservation Medicine

The goal of conservation medicine is the integration of the diagnostic and problem-solving tools of medical professionals with the ecological and management knowledge of conservation professionals to preserve biodiversity and maintain the health of interdependent species (including humans).

One outcome of this synergy might be the creation of an integrated appraisal process for examining ecological health concerns. Such an appraisal process would try to incorporate the concepts of sustainability, life-cycle analysis, and systems thinking (Anderson and Johnson 1997; Clark 1993). By emphasizing the use of contextual knowledge in decision-making and diagnosis, an integrated health assessment could serve as such a tool. How this tool is defined and used deserves a separate, more extensive discussion. We mention it here as a possible example of how the talents and skills of multiple disciplines within the sciences and social sciences can be organized practically.

Conservation medicine is in its infancy. We are only beginning to define the tasks that can achieve its overall goal. Those tasks include the following:

• training environmentally literate health professionals;

• breaking down disciplinary barriers to communication and cooperation;

• establishing the scientific underpinnings of the interrelationships between human, animal, and environmental health;

• encouraging broad participation in public education; specific targets include policy-makers, voters, and children;

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• being active in developing conservation and health policies that integrate human and animal concerns;

• encouraging broader definitions for concepts of health; and

• developing assistive technical applications, including

-noninvasive diagnostic and therapeutic tools;

-conservation-oriented reproductive biology, genetics, and medicine;

-techniques to minimize the spread of exotic species and diseases;

-development of epidemiological models that will integrate data on wildlife, human, and domestic animal health to improve understanding of the ecological dynamics of health and disease;

-techniques for capture, restraint, anesthesia, and analgesia; and

-techniques for determining age and marking and tracking individuals.

As natural communities shrink, wildlife populations decline and come under more stresses, and populations of humans and domestic animals grow, there are an increased number of health problems in all species and new opportunities for disease to cross taxonomic lines. Achievement of the tasks listed above will enable health professionals to develop the nontraditional skills and broad environmental concerns needed to work constructively as members of multidisciplinary conservation efforts.

Conclusion

If it is granted that biodiversity is at high risk, what is to be done? The solution will require cooperation among professions long separated by academic and practical tradition.
E.O. Wilson (1992)

Over time, the roles of veterinary and human medical practitioners have expanded with society's understanding of the relationships between species. The health community as a whole has a latent capacity to address environmental-health issues, but this will require new ways of thinking and new tools. We hope that through working with a diversity of environmental professionals, we can do for environmental health what medicine is trying to do for human and animal health: change the focus from the treatment of a pathological condition to the maintenance of health.

Conservation medicine can be characterized as a work in progress. It provides a framework for bringing the health-science professions into the realm of conserving biological diversity and ecosystems and for infusing conservation biology thinking into the health pedagogy. In the end, we hope to use this approach to help people understand that esoteric concepts like “conservation of biodiversity” are intimately connected to their own personal health and that of animals. We also hope that this paper will stimulate thinking and discussion and will lead to the further definition of how the medical perspective can bring added value to conservation efforts.

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