Modeling the impact of voluntary testing and treatment on tuberculosis transmission dynamics
International Journal of Biomathematics
Department of Applied Mathematics, Modeling Biomedical Systems Research Group, National University of Science and Technology, P. O. Box 939 Ascot, Bulawayo, Zimbabwe; Department of Mathematics, University of Zimbabwe, P. O. Box MP 167, Harare, Zimbabwe
A deterministic model for evaluating the impact of voluntary testing and treatment on the transmission dynamics of tuberculosis is formulated and analyzed. The epidemiological threshold, known as the reproduction number is derived and qualitatively used to investigate the existence and stability of the associated equilibrium of the model system. The disease-free equilibrium is shown to be locally-asymptotically stable when the reproductive number is less than unity, and unstable if this threshold parameter exceeds unity. It is shown, using the Centre Manifold theory, that the model undergoes the phenomenon of backward bifurcation where the stable disease-free equilibrium co-exists with a stable endemic equilibrium when the associated reproduction number is less than unity. The analysis of the reproduction number suggests that voluntary tuberculosis testing and treatment may lead to effective control of tuberculosis. Furthermore, numerical simulations support the fact that an increase voluntary tuberculosis testing and treatment have a positive impact in controlling the spread of tuberculosis in the community. © 2012 World Scientific Publishing Company.