Dynamics of a chronic virus infection model with viral stimulation delay

Abstract

We incorporate a viral stimulation delay into a chronic virus infection model and investigate its dynamical behavior by theoretic analysis and numerical simulations. The obtained results show that the viral stimulation delay may result in new specific model phenomena, such as the dependence of the upper bound of the model solutions on the delay, transient oscillations, the eventual instability of the immune control equilibrium, and the appearance of cytokine storms. In addition to Hopf bifurcation, we provide numerical simulations showing the existence of homoclinic bifurcation and singular closed orbits.