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Cell-to-cell infection cannot be ignored in the development of HIV in the host. The mathematical difficulty in (Wang et al. in J. Biol. Dyn. 11:455–483, 2016) is mainly due to the assumption of the equality of two parameters, in which they are the proportions of infection that lead to latency caused by virus-to-cell infection and cell-to-cell transmission, respectively. To overcome the restricted condition, we propose a more general HIV development model with virus-to-cell and cell-to-cell infection patterns with logistic growth and saturation incidence. By constructing a proper Lyapunov function we obtain the global stability of the disease-free equilibrium without this restricted condition, thereby the main result in (Wang et al. in J. Biol. Dyn. 11:455–483, 2016) removing the restricted condition is proved by using our method even if two parameters are not equal. We also investigate the existence of Hopf bifurcation of diseased equilibrium in four cases. [ABSTRACT FROM AUTHOR]

This work focuses on an HIV infection model with intracellular delay and immune response delay, in which the former delay refers to the time it takes for healthy cells to become infectious after infection, and the latter delay refers to the time when immune cells are activated and induced by infected cells. By investigating the properties of the associated characteristic equation, we derive sufficient criteria for the asymptotic stability of the equilibria and the existence of Hopf bifurcation to the delayed model. Based on normal form theory and center manifold theorem, the stability and the direction of the Hopf bifurcating periodic solutions are studied. The results reveal that the intracellular delay cannot affect the stability of the immunity-present equilibrium, but the immune response delay can destabilize the stable immunity-present equilibrium through the Hopf bifurcation. Numerical simulations are provided to support the theoretical results.

In this paper, we investigate an age-structured HIV infection model with logistic growth for target cell. We rewrite the model as an abstract non-densely defined Cauchy problem and obtain the condition which guarantees the existence of the unique positive steady state. By linearizing the model at steady state and analysing the associated characteristic transcendental equations, we study the local asymptotic stability of the steady state. Furthermore, by using Hopf bifurcation theorem in Liu et al., we show that Hopf bifurcation occurs at the positive steady state when bifurcating parameter crosses some critical values. Finally, we perform some numerical simulations to illustrate our results.

In this paper, we investigate an age-structured HIV infection model with logistic growth for target cell. We rewrite the model as an abstract non-densely defined Cauchy problem and obtain the condition which guarantees the existence of the unique positive steady state. By linearizing the model at steady state and analysing the associated characteristic transcendental equations, we study the local asymptotic stability of the steady state. Furthermore, by using Hopf bifurcation theorem in Liu et al., we show that Hopf bifurcation occurs at the positive steady state when bifurcating parameter crosses some critical values. Finally, we perform some numerical simulations to illustrate our results. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the dynamical properties for a model of delayed differential equations which describes a virus–immune interaction in vivo. The model has two time delays describing time needed for infection of cell and CTLs generation. The model admits three possible equilibria: infection-free equilibrium, CTL-absent infection equilibrium and CTL-present infection equilibrium. The effect of time delay on stability of the equilibria for the CTL immune response model has been studied. [ABSTRACT FROM AUTHOR]

We make a mathematical analysis of an age structured HIV infection model with both virus-to-cell and cell-to-cell transmissions to understand the dynamical behavior of HIV infection in vivo. In the model, we consider the proliferation of uninfected CD 4 + T cells by a logistic function and the infected CD 4 + T cells are assumed to have an infection-age structure. Our main results concern the Hopf bifurcation of the model by using the theory of integrated semigroup and the Hopf bifurcation theory for semilinear equations with nondense domain. Bifurcation analysis indicates that there exist some parameter values such that this HIV infection model has a nontrivial periodic solution which bifurcates from the positive equilibrium. The numerical simulations are also carried out. [ABSTRACT FROM AUTHOR]