Figure 1: Model of disease evolution on networks.
From: Evolution and emergence of infectious diseases in theoretical and real-world networks
Individuals are represented by nodes in a network (shapes) and connections between individuals through which the disease can spread are represented by edges (grey lines). (a) In a population of initially susceptible individuals (green circles), a single individual becomes infected (red hexagons). (b) The infection spreads throughout the population, and eventually reaches a dynamic equilibrium (becomes ‘endemic’), where the number of new infections is balanced by the number of recoveries. (c) The pathogen in a single individual gains a beneficial mutation, creating a new pathogen strain (blue octagon). We are interested in the probability that this new strain fixes in the population, reaching endemic equilibrium and causing the resident strain to go extinct.
