At a crossroads between biology and medicine, epidemiology is the study of infectious and non infectious diseases in populations. In particular, epidemiology of infectious diseases relies on the articulation between the biology of the germ and the biology of the host population. Virus-host interactions are studied by epidemiologists at different levels and from different perspectives. The concept of emerging infectious disease, elaborated in the 1990s, emphasizes the need to investigate both the molecular and ecological aspects of virus-host interactions. Molecular approaches (...) in epidemiology focus on the genetic, subcellular and cellular aspects of the host-germ relationship at the individual and population levels, while ecological approaches insist on the spatial distribution of host and germ populations, their relationships with their environment, and their interactions with other species. This paper describes integration processes at work between ecological and molecular approaches in the epidemiology of two RNA viruses since the advent of the concept of emerging infectious disease. Based on these two case studies, it further explores the meaning of integration, and aims at identifying the specific goals, challenges, expectations and issues associated with integration in these contexts. (shrink)

In the beginning of the 1990s, the concept of “emerging infectious disease” was elaborated in the United States in order to trigger institutional as well as conceptual changes in the fight against infectious diseases at national and international scales. For this reason it has been described as an “active concept” by sociologists Lorna Weir and Eric Mykhalovskiy. The impact at the institutional level of the EID concept has been described in detail, but the concrete consequences of this concept at the (...) level of research, on the agenda of researchers, remain poorly explored by historians, philosophers and sociologists of biology and medicine. One of the major consequences of the EID concept at the research level relies on the re-conceptualization of infectious disease emergence as a complex and multifactorial phenomenon, taking place inside a “dynamic and complex global ecology”. Taking rabies epidemiology as a case study, I illustrate how epidemiologists deal with the “global ecology” of this neglected old viral disease that is present everywhere on Earth except in Antarctica and still claims more than 55,000 lives annually. I further investigate the extent to which the complexity of rabies ecology is or is not perceived as an argument against the feasibility of rabies elimination or even eradication. Finally, this paper shows that the EID concept, finding its roots in the tradition of disease ecology, significantly impacts rabies epidemiology and despite its complexity, rabies ecology is not always perceived as an insurmountable obstacle to rabies elimination or eradication. (shrink)