The model has been encoded in COPASI 4.24 (Build 197) and the figure 3 of the publication has been reproduced using ggplot package in R.

The parameters for the intial concentration was provided by author upon contact T(0) = 10^6, I(0) = 10^6, VI(0) = 10^7 AND VNI(0) = 10^6 . Using these values the figures are reproducible.