Figure 4
Restrictions in commuting and their impact on disease spread. We consider a base network of size \(N=40\) and average migration rate \(\mu _{c}=0.12\), a scenario of uncontrolled disease spread (grey). We test the six mobility restriction strategies described in this section, which all result in successfully controlling the expansion of the disease by perturbing 10% of the commuting flows of the network to \(\mu _{c}^{*} = 0\). For each scenario, the top graph displays the strength of the commuting flow from patch i to patch j in its (i, j)-th cell. The brightness of the color represents the strength of the interaction, with white representing absence of interaction. Each line in the bottom graph shows the evolution of the infected population at each patch, colored according to its average incoming and outgoing commuting flow. The three targeted strategies (in shades of orange) consist of A: restricting all outgoing flows at 4 nodes, B: restricting all incoming flows at the same set of nodes as in A, C: restricting both incoming and outgoing flows at half of the nodes selected in the previous scenarios. The three random strategies (in shades of blue) consist of D: restricting randomly chosen unidirectional flows, E: restricting half as many randomly chosen flows in both directions, F: uniformly decreasing all the flows in the network. The bottom left graph shows the resulting epidemic threshold in terms of the number of perturbed nodes, as given by the analytical expressions provided by Eqs. (10)–(12) (continuous lines) and empirical computations from synthetic networks (dots).
