A computer virus model with graded cure rates

A dynamical model characterizing the spread of computer viruses over the Internet is established, in which two assumptions are imposed: (1) a computer possesses infectivity once it is infected, and (2) latent computers have a lower cure rate than seizing computers. The qualitative properties of this model are fully studied. First, the basic reproduction number, R-0, for this model is determined. Second, by introducing appropriate Lyapunov functions, it is proved that the virus-free equilibrium is globally asymptotically stable if R-0 <= 1, whereas the viral equilibrium is globally asymptotically stable if 1 < R-0 <= 4. Next, the sensitivity analysis of R-0 to three system parameters is conducted, and the dependence of R-0 on the remaining system parameters is investigated. On this basis, a set of policies is recommended for eradicating viruses spreading across the Internet effectively. (C) 2012 Elsevier Ltd. All rights reserved.