Asymptotical stability of an seis epidemic model with latent age dependence and generally nonlinear contact rate

In this paper, an SEIS epidemic model with latent age and generally nonlinear contact rate is formulated. The existence and asymptotic stability of equilibrium are discussed, respectively. In the same time, a general condition is obtained by the similar method utilized in [12], under which the endemic equilibrium is exponentially asymptotically stable. At last, a special example is presented to verified this condition.