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The influence of drug treatment on the maintenance of schistosome genetic diversity. (English) Zbl 0986.92017
Summary: Drug treatment of patients with schistosomiasis may select for drug-resistant parasites. We formulate a deterministic model with multiple strains of schistosomes (helminth parasites with a two-host life cycles) in order to explore the role of drug treatment in the maintenance of a polymorphism of parasite strains that differ in their resistance levels. The basic reproductive numbers for all strains are computed, and are shown to determine the stabilities of equilibria of the model and consequently the distribution of parasite phenotypes with different levels of drug tolerance. Analysis of our model shows that the likelihood that resistant strains will increase in frequency depends on the interplay between their relative fitness, the cost of resistance, and the degree of selection pressure exerted by the drug treatments.

MSC:
92C50Medical applications of mathematical biology
34D05Asymptotic stability of ODE
92C60Medical epidemiology