Bonsall Michael B, Raymond Ben
Department of Zoology, Mathematical Ecology Research Group, University of Oxford, South Parks Road, Oxford OX13PS, UK.
J Theor Biol. 2008 Sep 21;254(2):339-49. doi: 10.1016/j.jtbi.2008.05.036. Epub 2008 Jun 1.
Mixed pathogenic infections are known to have profound effects on the ecological and evolutionary diversity of both hosts and parasites. Although a variety of mechanisms have been proposed by which hosts can withstand parasitic infections, the role of multiple infections and the trade-off in multiple defence strategies remain relatively unexplored. We develop a stage-structured host-pathogen model to explore the ecological and evolutionary dynamics of host resistance to different modes of infection. In particular, we investigate how the evolution of resistance is influenced through infection by a lethal pathogen and a non-lethal synergist (that only acts to enhance the infectivity of the pathogen). We extend our theoretical framework to explore how trade-offs in the ability to withstand infection by the lethal pathogen and the ability to tolerate the synergist affect the likelihood of coexistence and the evolution of polymorphic host strategies. We show how the underlying structure of the trade-off surface is crucial in the maintenance of resistance polymorphisms. Further, depending on the shape of the trade-off surface, we predict that different levels of host resistance will show individual responses to the presence of non-lethal synergists. Our results are discussed in the wider context of recent developments in understanding the evolution of resistance to pathogen infections and resistance management.
已知混合病原体感染会对宿主和寄生虫的生态及进化多样性产生深远影响。尽管已经提出了多种宿主抵御寄生虫感染的机制，但多重感染的作用以及多种防御策略之间的权衡仍有待深入研究。我们构建了一个阶段结构的宿主-病原体模型，以探索宿主对不同感染模式的抗性的生态和进化动态。具体而言，我们研究了致死性病原体和非致死性协同因子（仅作用于增强病原体的感染力）的感染如何影响抗性的进化。我们扩展了理论框架，以探讨在抵御致死性病原体的能力和耐受协同因子的能力之间的权衡如何影响共存的可能性以及多态宿主策略的进化。我们展示了权衡表面的潜在结构在维持抗性多态性方面的关键作用。此外，根据权衡表面的形状，我们预测不同水平的宿主抗性将对非致死性协同因子的存在表现出个体反应。我们将在理解病原体感染抗性进化和抗性管理的最新进展这一更广泛背景下讨论我们的结果。
