April 2007 | Back to Table of Contents
Commentary
One Medicine—Today's Imperative
Veterinarians, physicians, and public health workers urgently need to work together to solve today's health dilemmas.
By William Hueston, D.V.M., Ph.D., Jeffrey Klausner, D.V.M., M.S., and Stephan Singleton, D.V.M.
The average American thinks of veterinarians as the gentle doctors who care for their beloved or bedeviled pets. Few people realize that veterinarians also are concerned about human health. And fewer recognize the increasing need for physicians and veterinarians to work together in a “one medicine” approach.
The idea of one medicine isn’t new. In the mid 1800s, German pathologist Rudolph Virchow argued that veterinarians and physicians must work together to effectively address infectious disease. While studying Trichinella in the 1850s, he coined the term “zoonosis” to describe diseases common to humans and animals.1 Recent reviews suggest that more than 60% of all infectious agents known to cause disease in humans are zoonotic; these shared agents include viruses, bacteria, fungi, external and internal parasites, and prions.2 The phrase “one medicine” was coined in the 1960s by American epidemiologist Calvin Schwabe, who was inspired by his work with Dinka pastoralist healers in Sudan who cared for both animals and humans.3 Whereas medical training has veered strongly toward specialization, one medicine represents “the general science of all human and animal health and disease.”4
The role of the veterinarian in one medicine is receiving renewed attention because of current events including the emergence of important new infectious diseases and the increased awareness of vulnerabilities in our food system. Julie Gerberding, M.D., director of the Centers for Disease Control and Prevention (CDC), has pointed out on numerous occasions that 75% of the emerging infectious disease threats to humans during the last decade also affect animals.5 In June 2003, CDC officials found themselves tracking 3 emerging zoonoses: monkeypox, SARS, and West Nile Virus. Gerberding proclaimed this to be “the new normal,” referring not only to the re-emergence of infectious diseases as a major public health threat but also to the recognition that many, if not most, of the new and re-emerging infectious diseases arise from animals.
Veterinarians in Diverse Roles
Not all public health veterinarians work with zoonoses and food safety. Their background in comparative medicine and population health prepares them well for a variety of positions, many of which are far removed from animals. Here are a few examples of veterinarians who are working in public health roles.
State
Joni Sheftel, D.V.M., M.P.H., state public health veterinarian, is responsible not only for rabies surveillance but also for surveillance of vector-borne diseases such as tularemia and plague plus foodborne illnesses.
Nikki Neeser, D.V.M., M.P.H., directs meat, poultry, egg, and dairy inspection for the Minnesota Department of Agriculture. She is responsible for all the state-inspected food-processing facilities.
Jane Tangwell, D.V.M., M.P.H. candidate, coordinates emergency exercises for the Minnesota Department of Health, preparing first responders and health care workers for everything from natural disasters to industrial accidents to catastrophic infectious disease outbreaks such as pandemic flu.
National
Lonnie King, D.V.M., M.S., M.P.A., director of the National Center for Zoonotic, Vector-Borne, and Enteric Diseases, Centers for Disease Control and Prevention (CDC), is one of more than 80 veterinarians working at the CDC. King leads the center responsible for prevention and control of disease, disability, and death from zoonotic, vector-borne, food-borne, water-borne, mycotic, and related infections.
Brigadier Gen. Theresa Casey, D.V.M., M.P.H., assistant surgeon general for the Air Force Modernization Directorate and Air Force Medical Service chief information officer. Along with other veterinarians, she is responsible for protecting the safety of food for the troops, occupational safety, and support of military biomedical research programs.
Margaret Bowman, D.V.M., M.P.H. candidate, is corporate food safety manager for Keystone Foods, a food processor with plants in Europe, Asia, and the United States. She and other veterinarians are responsible for quality assurance and research for major food, feed, pharmaceutical, medical device, and vaccine companies.
Suzanne Zane, D.V.M., a veterinarian and maternal health epidemiologist at the CDC, conducts national surveillance for deaths related to pregnancy, plans the national research agenda on maternal morbidity, and conducts research on unintended pregnancies.
Chand Khanna, D.V.M., Ph.D., heads the comparative oncology program at the National Cancer Institute. He is leading a research group that is using canine cancer models to advance knowledge of both human and animal cancers.
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Not only are pathogens constantly evolving (witness the highly pathogenic H5N1 avian influenza virus first identified in Hong Kong and now found in many parts of the world), but zoonoses account for the majority of the potential bioterrorism agents. Interestingly, practicing veterinarians encounter anthrax, tularemia, and other agents of concern during their practice. No wonder that a Princeton University physician posited a pressing need for closer collaboration among veterinarians, physicians, and public health experts to address these emerging infectious disease threats.6
The one medicine concept is not limited to infectious diseases. Comparative medicine, which looks at organ systems or disease processes across multiple species, has revolutionized the study of cancer and many metabolic diseases. For example, the successful treatment of Tetralogy of Fallot or “blue baby syndrome” was only possible after surgeries on Anna, a mixed-breed dog, who now is the unofficial mascot for comparative medicine at Johns Hopkins University.7 As our understanding of the genome expands, comparative medicine has taken on a new dimension with the development of highly inbred laboratory animals (primarily rats and mice). Researchers studying gene-deleted (“null”) animals or those with multiple copies of a specific gene are able to pinpoint the role of specific chromosomal components, benefiting from the fact that many segments of the animal genome are highly conserved, ie, identical in both humans and other animals.
Building on Common Scientific Training
Medical and veterinary curricula are remarkably similar during the first year or two. Anatomy, physiology, virology, and immunology are taught similarly. In fact, at some universities, the same faculty teach medical and veterinary students. The curricula diverge during the years of clinical training, as medical students focus exclusively on humans and veterinary students take more of a comparative medicine approach in order to prepare to address the needs of many different species. Interestingly, although medical and public health curricula are differentiated by a focus on the individual versus the population (community), veterinary education addresses both and touches on human public health issues that are linked to animals. Universities that bring together medical, veterinary, and public health students are seizing on a unique opportunity to instill the one medicine idea early in the careers of health professionals.
Although the phrase “one medicine” has not been universally recognized, numerous examples demonstrate the power of an interprofessional approach. Veterinarians’ work to eradicate brucellosis and tuberculosis in cattle combined with the widespread adoption of pasteurization of milk have effectively stopped human undulant fever and tuberculosis caused by Mycobacterium bovis in the developed world. Collaborations between physicians and veterinarians perfected techniques through experimental surgeries on animals that have led to external fixation of fractures and the surgically implanted prosthetic hip. Work by public health, food processing, and veterinary professionals has led to the on-farm prevention, sanitation, harvesting, and processing practices; the safeguards on imports; and the guidelines for cooking and cleaning that give the United States one of the most abundant, affordable, safe, and wholesome food supplies in the world.
Emerging Challenges of One Medicine
When the U.S. Surgeon General told Congress in 1969 that the battle with infectious diseases was almost over, he had no way of anticipating AIDS, SARS, avian influenza, and the myriad other emerging zoonoses we’ve seen in the last 38 years. Because of population growth around the world, the explosion in global travel, climate change, and public health infrastructure disparities, the risk and impact of infectious diseases may be increasing rather than decreasing. And our “war” metaphors no longer appear appropriate as the ecology of emerging infectious diseases becomes more and more complex. Instead of winning the war against infectious disease, our task now seems to be managing the dilemmas associated with these ever-changing threats to human health.
One medicine pulls together physicians, nurses, veterinarians, environmental health specialists, and public health workers along with engineers, epidemiologists, statisticians, and economists. The highly pathogenic H5N1 avian influenza and the threat of pandemic influenza are cases-in-point. The World Health Organization, Food and Agricultural Organization, and World Organization for Animal Health have formulated a unified strategy for tackling these issues: In the short run, the plan is to focus on the highly pathogenic H5N1 avian influenza at its source—in poultry in Southeast Asia, then to eradicate the strain, and, finally, to plan for pandemic influenza in humans.
Whether in implementing public health programs or biomedical research, physician-veterinarian-public health specialist collaborations are breaking new ground both in discovery and in application. As a result, demand for veterinarians to work in public health and biomedical research has never been greater. Veterinarians’ strengths in comparative medicine, infectious diseases, population health, and surveillance position them well for both public- and private-sector jobs that bring together aspects of animal health, human health, and the environment. MM
William Hueston is director of the University of Minnesota’s Center for Animal Health and Food Safety. Jeffrey Klausner is dean of the College of Veterinary Medicine at the University of Minnesota. Stephan Singleton is a veterinary public health resident at the University of Minnesota who is completing her master’s degree in public health.
References
1. Brown C. Virchow revisited: emerging zoonoses. Am Soc Microbiol. 2003;69:493-7.
2. Cleaveland S, Laurenson MK, Taylor LH. Diseases of humans and their domestic mammals: pathogen characteristics, host range, and the risk of emergence. Philos Trans R Soc Lond B Biol Sci. 2001;356(1411):991-9.
3. Swiss Tropical Institute. The One Medicine. Available at: http://www.sti.ch/research/environment/the-one-medicine.html. Accessed: March 8, 2007.
4. Zinsstag J, Schelling E, Wyss K, Mahamat MB. Potential of cooperation between human and animal health to strengthen health systems. Lancet. 2005;366(9503):2142-5.
5. APHA. Outbreaks of animal-related illnesses signal rising trend in infectious diseases. The Nation’s Health, August 2003. Available at: http://www.apha.org/publications/tnh/archives/2003/08-03/General/932.htm. Accessed: March 12, 2007.
6. Kahn LH. Confronting zoonoses, linking human and veterinary medicine. Emerg Infect Dis. 2006;12(4):556-61. Available at: http://www.cdc.gov/ncidod/eid/vol12no04/05-0956.htm. Accessed: February 17, 2007.
7. Johns Hopkins University. Anna’s story: an unofficial mascot for comparative medicine. Available at: http://www.hopkinsmedicine.org/mcp/Front_page/anna/index.html. Accessed: March 8, 2007