Figure 10

The trivial equilibrium \(\bar{E}_{4,0}\) is represented by the circle “”, the unstable endemic equilibrium \(\bar{E}_{4,1}\) is denoted by the rhombus “” and the stable endemic equilibrium \(\bar{E}_{4,2}\) is represented by the star “”. Simulations have been done with parameter values \(\lambda = 10\), \(\mu = 0.1\), \(\beta = 0.5\), \(\gamma = 0.1\), \(h = 60\), \(p = 3\), and \(L = 100\). Part (a) is produced with \(m = 0.8 m^{\star }\), while part (b) is produced with \(m = 1.5 m^{\star }\), where \(m^{\star } = 0.1335\)