Dynamics of a diffusive and delayed HIV infection model with impaired immunity and latent cell-to-cell transmission

Viral concentrations in plasma can be suppressed by antiviral drugs, yet reactivation of latently infected cells is the main obstacle to total human immunodeficiency virus (HIV) elimination. In this paper, to characterize the within-host dynamics of HIV with impaired immunity, we formulated and analyzed a general HIV infection model involving diffusion and three delays. Uninfected CD4 ${}^{+}$T cells were at risk of infection when they came into contact with three viral transmission routes, namely virus-to-cell infection, latent cell-to-cell transmission, and cell-to-cell transmission, all characterized by general incidence functions. Viral infection reproduction number was calculated, and the global properties were demonstrated. Numerical simulations were carried out to illustrate the corresponding theoretical results.