Effect of time delays in an HIV virotherapy model with nonlinear incidence.

In this paper, we propose a mathematical model for HIV infection with delays in cell infection and virus production. The model examines a viral therapy for controlling infections through recombining HIV with a genetically modified virus. For this model, we derive two biologically insightful quantities (reproduction numbers) [Formula: see text] and [Formula: see text], and their threshold properties are discussed. When [Formula: see text], the infection-free equilibrium E0 is globally asymptotically stable. If [Formula: see text] and [Formula: see text], the single-infection equilibrium Es is globally asymptotically stable. When [Formula: see text], there occurs the double-infection equilibrium Ed, and there exists a constant Rb such that Ed is asymptotically stable if [Formula: see text]. Some simulations are performed to support and complement the theoretical results.