Figure 4.

Snapshots of the spatial grid for the stochastic model with the small-world network, for two different values of τ ((a) τ=0.25 and (b) τ=1). The red, blue and black sites correspond to infected, recovered and susceptible individuals, respectively. For initial conditions including a few foci of infection in a completely susceptible population, clusters develop quickly, after a short initial spread that appears exponential. For (a) the lower transmission rates, the clusters interfere most with the further propagation of the disease as most infected individuals are in close contact with recovered and other infected individuals. This difference is apparent by comparing the clusters of infection for the two transmission parameters.