Comparison of the simulation results from mean-field approximation (MA), pair approximation (PA) and Monte Carlo simulation (MCS), depending on mortality cost and growth rate; (a). <i>β</i>_S = 10, (b). <i>β</i>_S = 30, (c). <i>m</i>_I = 15.

<p>(i) equilibrium density of healthy individuals () (ii) equilibrium density of infected individuals (). The dots, solid line and dashed line indicate the results of MA, PA and MCS, respectively. These results show that when <i>m</i>_I is low, both approximation methods present similar trend to MCS, although these methods overestimate the equilibrium value. (iii) The variance among 100 trials in MCS. A high variance means the oscillatory solution is observed.