Mathematical study of in-host dynamics of Chlamydia trachomatis

The paper presents a deterministic model for the dynamics of Chlamydia trachomatis inside the body of an infected human host. The model is shown to have a globally asymptotically stable Chlamydia-free equilibrium (CFE) whenever a certain epidemiological threshold, known as the basic reproduction number, is less than unity. It has a unique Chlamydia-present equilibrium (CPE) whenever the threshold quantity exceeds unity. The unique CPE is globally asymptotically stable under certain conditions. The model is extended to incorporate the effect of humoral and cell-mediated immune responses. The extended model also has a globally asymptotically stable CFE whenever its associated reproduction threshold is less than unity, and the disease persists when the threshold exceeds unity. Numerical simulations of the extended model show that cell-mediated immune response is more effective than humoral immune response (and that humoral immune response only offers marginal impact in curtailing Chlamydia dynamics). Furthermore, based on the parameter values used in the numerical simulations, this study shows that a future Chlamydia vaccine that boosts cell-mediated immune response would be quite effective in reducing Chlamydia burden.