Reconstructed bifurcation diagrams of CD4 cells and HIV-1 viral load dynamics under the effect of antiretroviral drugs

Abstract

Nonlinear methods such as chaos theory and bifurcation diagrams are useful for analyzing complex biological and medical systems. In this work, the bifurcation diagrams of CD4 cells and viral load dynamics under antiretroviral therapy have been reconstructed from the measured time series using a nonlinear dynamic model. The bifurcation parameter of the system was identified and the bifurcation diagrams were constructed. Results demonstrate that the CD4 and HIV-1 viral load under the influence of antiretroviral drugs (zidovudine, lamivudine and ritonavir) exhibits bifurcation behavior in short parameter ranges. Further, it was observed that the antiretroviral therapy may fail at certain values of the bifurcation parameter (μ = 7.769, 7.883 and 7.91), since there is a possibility of decrease in CD4 cell population at these values of the parameter. © 2013 Springer-Verlag Wien.