Diffusion des épidémies et complexités géographiques

Complexity theories focus on the interactions between entities in systems. Each entity of a complex system is organised in sub-levels and parallel levels interacting together in different ways. In geography, micro-level studies considering the spatial dynamic of epidemics as complex systems are quite rare. From a set of studies based on the analysis of the HIV/ AIDS epidemic in Mumbai (Bombay, India) and on the multi-agent based modelling of an epidemic, this paper explores several types of complexity : of levels, of the quantity of entities, and of the dynamics in non linear systems. First, we analyse the transition phases in a spatial diffusion process and the impact of circulation networks in the emergence of an epidemic. Second, we propose a new approach in the modelling of the spatial diffusion of an epidemic by combining both heterogeneity of space and patterns of mobility