A simple model of the build-up of resistance to mixtures of anti-malarial drugs

Abstract

In an organism with a life-cycle modelled on that of Plasmodium two separate resistance genes are assumed, each protecting against one of two unrelated drugs. The model was used to compare the rates of build-up of resistance in a population where the two drugs are used either as a mixture or in sequence. The model suggests that the use of a mixture would be advantageous if: (i) both resistances are initially rare; (ii) there is recombination between the genes; (iii) a large proportion of the parasite population is unexposed to the drugs.