Qualitative analysis of an SIR epidemic model with stage structure

An SIR epidemic model with stage structure consisting immature and mature stages is investigated. The global stability of epidemic equilibrium and disease-free equilibrium is proved. Meanwhile, we obtained that global dynamics is completely determined by the basic reproduction number σσ. If σ<1σ<1, the disease-free equilibrium is globally stable and the disease dies out. If σ>1σ>1, a unique endemic equilibrium is globally stable in the interior of a feasible region and the disease persists at endemic equilibrium.