Figure 2.

One-parameter bifurcation diagrams and example time-series for the two-disease age-structured model. Bifurcation diagrams for (a) measles–whooping cough, (b) measles–chickenpox and (c) measles–rubella interactions. The related parameters are listed in table 1. Panels (b), (d) and (f) plot the cycles corresponding to the three pairs of two-disease interactions, respectively (for seasonal amplitude b=0.2). Similar to figure 1, measles, whooping cough, chickenpox and rubella are identified by different degrees of darkness in a decreasing order. The convalescent period is about 7 days for measles and 14 days for the other three diseases. Disease-induced mortality for both diseases is zero.