(ProQuest: ... denotes non-US-ASCII text omitted.)I believe that there is no dichotomy between the natural world and the human environment.-Juliet Clutton-Brock (1994:23)Shifting the Medical Anthropology LensAs Herzog and Burghard accurately observe, would be difficult to overestimate the significance of animals in the social and psychological life [as well as the biology] of our (1988:214). It would be equally difficult to overestimate the impact of our species on other animals, but also on plants and even quasi-living/quasi-species like viruses (e.g., the role of changes in human ecology, such as penetration of forested areas, in the zoonotic transformation of SIVcpz into HIV-1 or SIVsm into HIV-2). Impactful interactions between and other organisms-a relationship Shipman (2010, 2011) refers to as the animal connection-commonly are not time-limited but ongoing and substantially influenced the evolution of humans (Shipman 2010:519). Dogs, for example, have had a persistent presence in human communities for probably well over 15,000 years (Germonpre et al. 2009), with significant consequences for both species. This began with genetic and behavioral changes in wolves that produced dogs, followed by the subsequent appearance of diverse dog breeds and mixes, and extending to the multiple biological, cognitive, emotional, cultural, economic, etiological, prophylactic, therapeutic, and other impacts on of association with dogs. One outcome of enduring interaction is the emergence of a mutual causation process, in which species A (e.g., a new human behavior such as the adoption of backyard flower pots as household decorations in urban areas) facilitates responsive changes in species B (e.g., adoption by malaria-bearing mosquitoes of new breeding habitats that include use of backyard flower pots), which, in turn, evokes subsequent changes in species A (e.g., significant increases in the incidence of human malaria infection in urban settings and the adoption of new antibiotics to fight malaria), which impact and lead to new changes in species B (e.g,. genetic alterations that enable resistance to the new antibiotics), and so on (Kwa 2008). A classic case of this kind of co-evolution was presented by Livingston (1958), who proposed that human development of iron tools in Africa several thousand years ago allowed the clearing of tropical forests for horticulture, which, in turn, contributed to the appearance of sun-warmed pools of stagnant water that were adopted as breeding sites by anopheline mosquito vectors of the Plasmodium family of protozoa, infectious agents of malaria. The result was a significant jump in human malaria infection, human suffering, and the selection for and increase of the sickling trait in human plasma, which offered a degree of protection from malaria. Cormier (2010:257) posits a somewhat similar account of New World malaria involving the transfer of the disease from Old World human populations to neotropical New World monkey species during the colonial era, which, because of certain cultural practices, like the hunting of monkeys for food and the raising of captured baby monkeys as pets, set up close interactions... where diseases can be shared between monkeys and people. Humans responded with the development of new (or adapted) cultural practices-like the bathing of infected individuals in aromic plants-to treat malarial fevers.As these examples suggest, causal processes involve relationships that evolve and change together in such a way (with feedback and feed-forward) as to make the distinction between cause and effect meaningless (Guba 1985:88). What are the implications of this kind of process for medical anthropology, and have we fully engaged a relational model that views people and other organisms as mutually constitutive (de Vries 2011 ) in our approaches to ethnographic health research?In the introduction to a themed issue of the journal Cultural Anthropology entitled Emergence of Multispecies Ethnography, Kirksey and Helmreich observe:Creatures previously appearing on the margins of anthropology- as part of the landscape, as food for humans, as symbols-have been pressed into the foreground in recent ethnographies. …