It was Calvin Schwabe’s thorough rethinking of the concept of “one medicine” in 1976 that fully recognized the close systemic interaction of humans and animals for nutrition, livelihood and health. International organizations such as the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) have institutionalized “one medicine” partly as Veterinary Public Health (VPH), the contribution of veterinary medicine to public health. “One health” has seen unprecedented revival in the last decade with fostered awareness, scientific debate, research programmes, integrated disease surveillance and an open toolbox in the fields of disease surveillance, epidemiological studies and health care provision.
Ancient healers were often priests and cared for both humans and animals. They gained anatomical and pathological skills from slaughtering sacrificial animals and deciding on their purity for sacrifice. Veterinary medicine appears to have been a distinct discipline during the Zhou Dynasty in China (11–13th century). The Zhou Dynasty had one of the earliest organizations of an integrated public health system including medical doctors and veterinarians. A Chinese text by Xu Dachun (‘on the origin and development of medicine’) from the 18th century states that: “The foundations of veterinary medicine are as comprehensive and subtle as those of human medicine and it is not possible to place one above the other” (translated from German). Claude Bourgelat, the founder of the first veterinary school in Lyon in 1762, was heavily criticized when he recommended human clinical training for the veterinary curriculum. However, in the 19th century, with the advent of cellular pathology, scientists like Rudolf Virchow developed a strong interest in linking human and veterinary medicine as a form of comparative medicine based on the discovery of similar disease processes in humans and animals. For example, major animal diseases such as rinderpest, rather than human epidemics, were the stimulus for medical research in South Africa and tsetse fly (Glossina spp.) control was motivated primarily by cattle trypanosomiasis.
Integrated medical thinking was conveyed to North America by William Osler, a student of Virchow. He is credited for having coined the term “one medicine”, although no direct written evidence for this has been found. In the 20th century, both sciences specialized to such an extent that their association was hardly visible and less often practiced. It was Calvin Schwabe’s thorough rethinking of the concept of “one medicine” in 1976 that fully recognized the close systemic interaction of humans and animals for nutrition, livelihood and health. Today, the earliest forms of healing of humans and animals are still widely practiced in traditional pastoral societies. It is thus not surprising that the contemporary “one medicine” idea grew out of experiences in African communities. It was conceived and conceptually consolidated during Calvin Schwabe’s work with Dinka pastoralists. It basically means that there is no difference of paradigm between human and veterinary medicine, and is an extension of notions of comparative medicine that were prevalent in North American veterinary and medical schools in the 1970s and 1980s. Both sciences share, as a general medicine, a common body of knowledge in anatomy, physiology, pathology, and the origins of diseases in all species. For example, close genomic relationship of animals and humans exists in cancer genetics, and many cancer genes were discovered in animals prior to identifying similar pathologies in humans. Such cross-over work should, however, not lead to an “Other one medicine”, but should contribute to the convergence of an integrated approach to health of all species.
International organizations such as the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) have institutionalized “one medicine” partly as Veterinary Public Health (VPH), the contribution of veterinary medicine to public health. The concept of “ecosystem health” extends “one medicine” to the whole ecosystem, including wildlife. Sustainable development depends on the mutualism of health and well-being of humans, animals and the ecosystems in which they coexist. Conservationists have recognized and promoted what are known as the “Manhattan principles”, that the health and sustainable maintenance of wildlife in natural reserves are mutually interdependent with the health of communities and the livestock surrounding them. Finally, many of the causative agents with bioterrorism potential are zoonoses and hence require mutual animal and public health vigilance for rapid detection. The term “one medicine”, having a rather clinical connotation, reflects insufficiently the interactions between human and animal health that reach far beyond individual clinical issues and include ecology, public health and broader societal dimensions. “One medicine” evolves thus towards “one health” through practical implementation and careful validation of contemporary thinking on health and ecosystems and their relevance for global public and animal health development.
A strategic framework for reducing risks of infectious diseases at the animal-human-ecosystem interfaces was first released at the 6th International Ministerial Conference on Avian and Pandemic Influenza in Sharm el-Sheikh, in October 2008 and has further evolved under the trademark protected term “One World One HealthTM” during an expert consultation in Winnipeg, Canada in 2009. “One health” has seen unprecedented revival in the last decade with fostered awareness, scientific debate, research programmes, integrated disease surveillance and an open toolbox in the fields of disease surveillance, epidemiological studies and health care provision. Despite all efforts of cooperation between human and animal health, isolated silo thinking persists, particularly in the public health sector. For example, an official of the Canadian Food Safety Agency (CFIA) complained about the lack of cooperation with human health counterparts in testing involved people. How can the public health sector perceive advantages of using “one health”? Demonstrating evidence of an added value of “one health” compared to conventional separated sectoral approaches is the major task that lies ahead, and represents the unfinished agenda of “one health” in view of further systemic conceptual developments. Further evidence of public health benefits by interventions in animals, by joint health care provision, or by joint disease surveillance, should be generated to foster interactions between human and animal health at the academic level, in ministries and in international organizations in industrial and developing countries.