Figure 3.

The role of quarantine. (a) Disease progress curves in the two regions with treatment allocation shown in the inset, together with quarantine (best path with quarantine; blue line, region 1; red line, region 2). (b) Quarantine effort and corresponding value for γ: note the sudden change in quarantine policy (best path: quarantine effort; light pink line, Q; dark pink line, γ). (c) Phase portrait showing how a potentially explosive epidemic (cf. figure 1j and table 1) can be brought under control by optimizing quarantine together with preferential treatment of the region with the lower prevalence of infection (proportion infected). Default parameters as in figure 1, except that p=1, b=100, Q_max=5 and γ=γ₀h(Q), where γ₀=0.03 and .