where R 0 is as defined in equation (9) When R C v1 infected individuals will have more chances of recovery than of transmitting the disease further hence the epidemic will die out. When R C w1, there exists an endemic equilibrium point as shown in Supporting Information S2 given by p . This implies that the endemic stationary point is attained via damped oscillations. The stability of this point would depend on the sign of the real part, a. If a.0, then the steady state is an unstable spiral, otherwise, it is a stable spiral. If ½j(mzf)z(mzr) 2 4jm(mzfzr) w1, then we have real roots, and stability of this equilibrium state will depend on the signs of these roots. If both are positive, the steady state is an unstable node; if both are negative, it is a stable node. If one of them is positive and the other negative, the steady state is a saddle point. Figure 2a shows the evolution of the malaria infected, M, the exposed, E, and the infected, I with time, while Figure 2b is a phase space portrait in the SI plane. From equation (14) it can be seen that the value for R C is determined by the proportions of susceptibles and malaria infectives in the population. Rearranging and assuming that SzM~1 this equation gives a criteria for an epidemic of