Jin Xu

Date of Award


Degree Type


Degree Name

Master of Science


Applied Mathematics


Dr. Xingfu Zou


More than one sub-type of HIVs have been identified. This raises an issue of co-infections by multiple strains of HIVs. In this thesis, we propose two mathematical models, one ignoring intracellular delay and the other incorporating the delay, to describe the interactions of the populations of CD4+cells and two HIV stains. By nature, the two strains compete for CD4+ cells to invade for their own replications. By analyzing the two models, we find that the models demonstrate threshold dynamics: if the overall basic reproduction number Ro < 1, then the infection free equilibrium is globally asymptotically stable; when R0 > 1, then the competition exclusion principle generically holds in the sense that, except for the critical case R\ = R2 > 1 where /?, is the individual basic reproduction number for strain i, all biologically meaningful solutions will converge to the single infection equilibrium representing the winning of the strain that has greater individual basic reproduction number. Numerical simulations are also performed to illustrate the theoretical results. The results on the model with delay also show that the basic reproduction number will be over calculated if the cellular delay is ignored.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.