EcoHealth 7, 237–241, 2010 DOI: 10.1007/s10393-010-0326-x Original Contribution 2010 The Author(s). This article is published with open access at Springerlink.com Pathocenosis: A Holistic Approach to Disease Ecology Jean-Paul Gonzalez,1,2,3 Micheline Guiserix,4 Frank Sauvage,4 Jean-Se´bastien Guitton,5 Pierre Vidal,6 Narge`s Bahi-Jaber,7 Hechmi Louzir,7 and Dominique Pontier4 1International Centre for Scientiﬁc Researches, Franceville (CIRMF), BP 2105 Libreville, Gabon 2French Ministry of Foreign and European Affairs, Paris, France 3Department of Health and Societies, Institut de Recherche pour le De´velopement, Marseille, France 4UMR-CNRS 5558, Universit´e de Lyon, Universit´e Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France 5Ofﬁce National de la Chasse et de la Faune Sauvage, Direction des E´tudes et de la Recherche, 39 Bd Albert Einstein, CS 42355, 44323 Nantes Cedex 3, France 6Department of Anthropology, Paris X University and French Ministry of Foreign Affairs, 11340 Roquefeuil, France 7Laboratoire d’Immunopathologie, Vaccinologie et G´en´etique Mole´culaire, Institut Pasteur de Tunis, 13 Place Pasteur, 1002 Tunis-Belv´ed`ere, Tunisia Abstract: The History of medicine describes the emergence and recognition of infectious diseases, and human attempts to stem them. It also throws light on the role of changing environmental conditions on disease emergence/re-emergence, establishment and, sometimes, disappearance. However, the dynamics of infectious diseases is also inﬂuenced by the relationships between the community of interacting infectious agents present at a given time in a given territory, a concept that Mirko Grmek, an historian of medicine, conceptualized with the word ‘‘pathocenosis’’. The spatial and temporal evolution of diseases, when observed at the appropriate scales, illustrates how a change in the pathocenosis, whether of ‘‘natural’’ or anthropic origin, can lead to the emergence and spread of diseases. Keywords: pathocenosis, emergence, infectious diseases INTRODUCTION The history of medicine gives the epidemiology of infec- tious diseases a unique perspective in time and space, highlighting possible relationships between different dis- eases occurring in particular economic and social contexts. In 1933, Charles Nicolle proposed a dynamic concept of the ‘‘birth, life and death of infectious diseases’’ to highlight the continuity and dynamics of what we could call the pathogenic domain of a given host population, i.e., the disease combinations observed at a given time (Nicolle, Published online: July 1, 2010 Correspondence to: Jean-Paul Gonzalez, e-mail: jean-paul.gonzalez@ird.fr 1933). This approach focuses on the processes of disease development and succession at the scale of the host pop- ulation. Charles Nicolle (1919 in Blanc and Baltazard, 1944) also proposed the pioneering concept of ‘‘asymp- tomatic infection,’’ crucial for understanding the sudden appearance (i.e., emergence) of certain diseases through clinical signs in particular circumstances. In 1969, Mirko Grmek proposed considering diseases of a given host population as a whole, including their historical and geographic dimensions. By analogy with ‘‘biocenosis,’’ which is the ecological concept of all living organisms that coexist and interact within a deﬁned territory, Grmek deﬁned pathocenosis as follows: ‘‘By pathocenosis, I mean the qualitatively and quantitatively deﬁned group of