THE COUPLED WITHIN-AND BETWEEN-HOST DYNAMICS IN THE EVOLUTION OF HIV/AIDS IN CHINA

In this work, we develop and analyze mathematical models for thecoupled within-host and between-host dynamics caricaturing the evolutionof HIV/AIDS. The host population is divided into susceptible, the infectedwithout receiving treatment and the infected receiving ART treatment in accordancewith China’s Four-Free-One-Care Policy. The within-host model is a typicalODE model adopted from literatures. The between-host model incorporatesage-since-infection described by a system of integrodifferential equations. Thetwo models are coupled via the viral load and number of CD4+ T cells ofwithin the hosts. For the between-host model with an arbitrarily selectedHIV infected individual, we focus on the analyses of the basic reproductionnumber R0 and the stabilities of equilibria. Through simulations we also findthat the within-host dynamics does influence the between-host dynamics, andthe nesting of within-host and between-host play a very important role in theHIV/AIDS evolution.