Dynamics of a viral infection model with delayed CTL response and immune circadian rhythm

This paper studies the global dynamics of a viral infection model that takes into account circadian rhythm and time delay in the CTL response. It is shown that the basic reproduction numbers, R0R0 and R1R1, determine the outcome of viral infection. Numerical simulations demonstrate that the changes in the amplitude of lytic component can generate a variety of dynamical patterns, ranging from simple daily oscillation to multi-day dynamics and eventually chaos, whereas time delay can alter the period of oscillation for the larger level of periodic forcing. These results can help to explain the viral oscillation behaviors, which were observed in chronic HBV and HCV infection patients.