Fig. 4.
We calculated E[ρ], the expected prevalence of mixed infection, in a study with nmix = 75 individuals detected with mixed infection among n = 500 patients. In (a) for fixed values of the average number of minority type cells in sputum, Emin = 25, and of the sensitivity threshold f = 0.01 we can see a numerical evidence that E[ρ] depends on the difference of the growth rates λY – λX and not on the two growth rates independently; this is confirmed by the deterministic approximation, Eq. (17). In panel (b) how E[ρ] varies taking into account the difference λY – λX on the x-axis and the parameter Emin on the y-axis is shown. From panel (b) we note that there is a large area (bottom-right) in the parameter space where E[ρ] is close to 1, estimate very far from the detected 0.15. Although E[ρ] decrease rapidly from 0.9 to 0.6, most part of the parameter space features an expected prevalence of mixed infection larger than 0.3.