Dipartimento di Matematica, Università di Trento Via Sommarive 14 38050 Povo, Italy.
Adv Exp Med Biol. 2010;673:32-50. doi: 10.1007/978-1-4419-6064-1_3.
Some models are presented for the dynamics of a host population with two parasite species. The models differ in two main aspects: whether they include direct competition among parasites and whether the analysis is based on some approximation and which one. If the analysis is not constrained by a priori assumptions about parasite distributions, it is found that species coexistence is very unlikely without some kind of direct competition among parasites; on the other hand, coexistence generally occurs when inter-specific competition is lower than intraspecific, similarly to standard theory for free-living species. If hosts differ in their predisposition to infection, but not in an identical way towards the two parasite species, then species coexistence becomes feasible even if inter-specific competition is as strong as intraspecific; in this case, coexistence becomes easier as the variance in predisposition increases. These models do not yield universal predictions for patterns of parasite distributions; an analysis of the mechanisms of interaction in each specific system is necessary for that.
有些模型被提出用于研究具有两种寄生虫物种的宿主种群的动态。这些模型在两个主要方面有所不同：它们是否包括寄生虫之间的直接竞争，以及分析所基于的近似方法是哪一种。如果分析不受寄生虫分布的先验假设的限制，那么如果没有某种寄生虫之间的直接竞争，物种共存就极不可能；另一方面，当种间竞争低于种内竞争时，通常会发生共存，这与自由生活物种的标准理论类似。如果宿主在感染易感性方面存在差异，但不是对两种寄生虫物种以相同的方式存在差异，那么即使种间竞争与种内竞争一样强烈，物种共存也变得可行；在这种情况下，随着易感性变异的增加，共存变得更容易。这些模型并不能对寄生虫分布模式做出普遍的预测；对于这种情况，有必要对每个特定系统中的相互作用机制进行分析。
