Dynamical behaviour of a delay differential equation of Hepatitis B virus

In this paper, we investigate a class of virus dynamics model with intracellular delay and nonlinear infection rate of saturated functional response. The basic reproduction number R0 for the viral infection is derived, and the global dynamics behavior are completely determined by R0. By constructing suitable Lyapunov functional and using LaSalle invariant principle for the delay differential equations, we find when R0 ≤ 1, the infection-free equilibrium is globally asymptotically stable, and when R0 > 1, the infection equilibrium is also globally asymptotically stable.