Towards more realistic host-parasite models

寄生吸虫与其无脊椎动物和脊椎动物宿主之间的相互作用是复杂的。这些相互作用的系统的模型也同样复杂，以便捕捉系统的生物学相关特征。这一领域中许多问题的进展面临困难，部分原因是模型中涉及的参数数量很大，而且现有数据有限。研究人员结合寄生虫学家的理论和经验，以及数学家的建模和理论专业知识来开发和研究这些模型。该项目的工作包括三个方面：第一，提出了宿主-寄生虫相互作用的新模型，由于生物学考虑和新获得的数据，提出了更复杂的模型；第二，对每个模型的一些数学性质进行了研究，并评估了它们的生物学和生态学影响，如寄生虫种群控制或潜在的物种灭绝；第三，通过模型结果与现场数据的比较对模型进行了验证。该项目的目标是为研究与宿主-寄生虫相互作用相关的问题开发一个理论框架。我们使用了一种特殊的宿主-寄生虫系统，人-血吸虫-蜗牛(大型寄生虫病)，以突出我们方法的普遍性。具体目标是建立数学模型，以了解宿主-寄生虫相互作用的各种成分在疾病传播动力学中的作用，确定模型中哪些生物细节是关键成分，构建和分析其中参数与现场数据容易相关的适当模型，并为现场工作人员和公共卫生政策制定者提供有用的信息。该项目通过为研究自然系统提供有用的模型，通过分析它们对影响动力学的参数的敏感性，以及通过允许将系统的复杂性组织成等级，显著地促进了我们对包括中间宿主的宿主-寄生虫系统动力学的了解和理解。同样重要的是，有可能帮助解决通过化疗控制血吸虫病的一些理论问题。

Feng, Milner, Minchella The interactions between parasitic trematodes and theirinvertebrate and vertebrate hosts are complex. Models of theseinteracting systems are similarly complex in order to capturebiologically relevant features of the systems. Advances for manyquestions in this area face difficulties in part because of thelarge number of parameters involved in the models and because ofthe limited data available. The investigators combine thetheoretical and empirical experience of a parasitologist and themodeling and theoretical expertise of mathematicians to developand investigate these models. The work of this project isthreefold: first, new models are proposed for host-parasiteinteractions, with more complex models motivated by biologicalconsiderations and newly available data; second, a study of somemathematical properties of each model is carried out and theirbiological and ecological implications assessed, such as parasitepopulation control or potential species extinction; third,validation of the models through comparison of model results withfield data follows. The goal of the project is to develop a theoreticalframework for the study of questions associated withhost-parasite interactions. A particular host-parasite system isused, human-schistosome-snail (macroparasitic disease), tohighlight the generality of our approach. Specific objectives areto develop mathematical models to understand the role of variouscomponents of host-parasite interactions in the diseasetransmission dynamics, to determine which biological details arecritical components in the model, to construct and analyzeappropriate models in which the parameters are readily related tofield data, and to provide useful information for field workersand policy makers in public health. The project significantlyadvances our knowledge and understanding of the dynamics ofhost-parasite systems that include intermediate hosts, byproviding usable models to study natural systems, by analyzingtheir sensitivity to the parameters affecting the dynamics, andby allowing structuring of the complexities of the systems intohierarchies. Just as important is the possibility to help addresssome of the theoretical issues in the control of schistosomiasisvia chemotherapy.