Virchow Revisited : Emerging Zoonoses

T he German physician Rudolf Virchow (1821–1905) was studying Trichinella in 1855 when he coined the term “zoonosis.” His work on this disease helped to convince him of the importance of linking human and veterinary medicine, something he emphasized throughout his career. Although Virchow is more widely heralded for his cell theory of disease, perhaps his concept of one medicine will become his important legacy. Today, our renewed emphasis on disease emergence is blurring the interface between animal and human health, with diseases blending like figures in an Escher drawing. Emerging diseases, a field of biomedicine that began with the discovery of AIDS, continues to expand. Most emerging diseases in humans are zoonotic in origin. AIDS, for example, apparently transferred to humans from primates—specifically, chimpanzees and sooty mangabeys. Virchow could hardly have envisioned how his concept of one medicine would become so central to public health by the third millenium. In the century and a half since Virchow first used the term zoonosis, we have made incredible progress in the biological sciences, including sequencing the human genome and those of many important microbial pathogens. Ironically, while developing an ever-more-sophisticated understanding of the host, its many responses to infectious agents, and their virulence factors, we also are facing a dramatic increase in the number of new diseases affecting that host, with the majority of those diseases originating in animals. Several Factors Boost Likelihood of Infectious Diseases Emerging