Abstract
This paper studies the global stability of pathogen dynamics model with pathogen-to-cell and cell-to-cell transmissions. We consider three types of time delays and two types of infected cells, latent and active. The model is given by a system of nonlinear delay differential equations which is discretized by utilizing nonstandard finite difference scheme. Positivity and boundedness properties of the solutions are proven. Global stability of the equilibria is established by constructing Lyapunov functions and applying LaSalle's invariance principle.