Global dynamics of a malaria model with partial immunity and two discrete time delays

Asymptotic properties of a malaria model with partial immunity and two discrete time delays are investigated. The time delays represent latent period and partial immunity period in the human population. The results obtained show that the global dynamics are completely determined by the values of the reproductive number. Using a suitable Lyapunov function the endemic equilibrium is shown to be globally asymptotically stable under certain conditions. Moreover, we show that when the partially immune humans are assumed to be noninfectious, the disease is uniformly persistent if the corresponding reproductive number is greater than unity.