Department of Mathematics, Southern Illinois University, Carbondale, IL 62901, USA.
J Theor Biol. 2012 Jul 7;304:197-210. doi: 10.1016/j.jtbi.2012.03.040. Epub 2012 Apr 8.
Motivated by relatively recent empirical studies on Schistosoma mansoni, we use a mathematical model to investigate the impacts of drug treatment of the definitive human host and coinfection of the intermediate snail host by multiple parasite strains on the evolution of parasites' drug resistance. Through the examination of evolutionarily stable strategies (ESS) of parasites, our study suggests that higher levels of drug treatment rates (which usually tend to promote monomorphism as the evolutionary equilibrium) favor parasite strains that have a higher level of drug resistance. Our study also shows that whether coinfection of intermediate hosts affects the levels of drug resistance at ESS points and their stability depends on the assumptions on the cost of parasites paid for drug resistance, coinfection functions and parasites' reproduction within coinfected hosts. This calls for more empirical studies on the parasite.
受近期有关曼氏血吸虫的实证研究的启发，我们使用一个数学模型来研究对终宿主进行药物治疗以及中间宿主的多重寄生虫株共感染对寄生虫抗药性演变的影响。通过检查寄生虫的进化稳定策略（ESS），我们的研究表明，较高的药物治疗率（通常倾向于促进单态性作为进化平衡）有利于具有更高抗药性的寄生虫株。我们的研究还表明，中间宿主的共感染是否会影响 ESS 点的抗药性水平及其稳定性取决于对抗药性、共感染功能和共感染宿主内寄生虫繁殖所付出的寄生虫代价的假设。这需要对寄生虫进行更多的实证研究。
