Collaborative Research: Understanding the Diversity of Parasites and Infectious Diseases in Three Mammalian Orders

病原体和寄生虫是生物多样性的主要组成部分，对自然种群有重要影响。寄主-寄生虫生态学的一个中心问题是，寄主行为、生活史和环境的哪些特征最能解释传染病的多样性和传播。重大的理论进展促进了我们对影响种群内传染病动态的因素的理解，但相对较少的研究分析了作为病原体多样性和特征变化基础的生态变量。该项目将检查三个哺乳动物目的寄生虫多样性模式，以明确测试从流行病学模型和陆地生物地理学理论中得出的预测。该项目将解决的主要问题包括：(1)决定野生哺乳动物种群中寄生虫种类和多样性变异的关键生态变量是什么？(2)寄生虫的传播方式和特异性程度如何取决于宿主生态？(3)宿主的进化多样性是否与寄生虫物种丰富度的模式相关？(4)寄生虫多样性的知识是否对野生动物保护有重要意义？建立一个关于感染野生哺乳动物的病原体和寄生虫的大型数据库是进行全面分析的关键，也是该项目的主要目标。研究人员最近建立了一个关于灵长类动物病原体和寄生虫的大型数据库，并将把这项工作扩展到另外两个研究良好的类群--食肉动物和有蹄类动物。这些数据库收集了(I)与疾病传播理论模型相关的生态、行为和生活史特征，(Ii)从野生种群中恢复的寄生虫和病原体的记录，(Iii)寄生虫传播方式和宿主专一性程度的数据，以及(Iv)宿主的系统发育信息。数据库的开发需要巨大的努力，在这项研究之后，所有数据都将在万维网上免费提供，以便其他科学家能够获得这项实验的成果。了解寄生虫多样性和特征背后的因素对于管理易受伤害的野生动物种群和减轻对人类健康的威胁至关重要。这项研究扩展了以前宿主-寄生虫比较工作的范围，通过检查丰富的微型和大型寄生虫多样性，包括关于寄生虫特征的信息，并通过评估涉及树木拓扑、分支长度和宿主多样化速率的系统发育信息。分析比较方法将控制抽样努力，同时测试多变量，并将评估寄主和寄生虫的特征是否与系统发育相关。一种将生态学、寄生虫学、流行病学和系统发育比较方法联系起来的综合方法对于开发一个广泛的概念框架来解释寄生虫多样性和与宿主特征相关的特征至关重要。为了推进这些目标，研究人员将组织三次由每个学科的专家组成的年度研讨会，以完善比较研究的预测，探索研究宿主-寄生虫组合中生态和进化相互作用的方法，并为理论和实证工作制定未来方向。

Pathogens and parasites are a major component of biological diversity, and haveimportant impacts on natural populations. A central question in host-parasite ecology concernswhat features of host behavior, life history, and environment best explain the diversity andevolution of infectious diseases. Significant theoretical progress has advanced our understandingof factors that influence infectious disease dynamics within populations, yet relatively fewstudies have analyzed ecological variables that underlie observed variation in pathogen diversityand characteristics. This project will examine patterns of parasite diversity across threemammalian orders to explicitly test predictions derived from both epidemiological models andisland biogeography theory. Major questions this project will address include (1) What are thekey ecological variables that determine variation in the types and diversity of parasites in wildmammal populations? (2) How do parasite transmission mode and the degree of specificitydepend on host ecology? (3) Does evolutionary diversification of hosts correlate with patterns ofparasite species richness? (4) Does knowledge of parasite diversity have important implicationsfor wildlife conservation?Establishing a large database on the pathogens and parasites infecting wild mammals iscritical to conducting comprehensive analyses and represents a major goal of this project. Theinvestigators have recently assembled a large database on the pathogens and parasites ofprimates and will extend this effort to two other well-studied groups - carnivores and ungulates.These databases capture (i) ecological, behavioral and life history traits relevant to theoreticalmodels of disease spread, (ii) records of parasites and pathogens recovered from wildpopulations, (iii) data on parasite transmission mode and degree of host specificity, and (iv)phylogenetic information on the hosts. Database development requires an immense effort andfollowing this study all data will be made freely available over the World Wide Web so thatother scientists can access the fruits of this labor.Understanding factors that underlie parasite diversity and characteristics is vital tomanaging vulnerable wildlife populations and mitigating threats to human health. This studyextends the scope of previous host-parasite comparative work by examining a rich diversity ofboth micro- and macroparasites, including information on parasite characteristics, and byassessing phylogenetic information involving tree topology, branch lengths and rates of hostdiversification. Analytical comparative methods will control for sampling effort, test multiplevariables simultaneously, and will assess whether host and parasite traits are correlated withphylogeny. A synthetic approach that links ecology, parasitology, epidemiology, andphylogenetic comparative methods is crucial for developing a broad conceptual framework toexplain parasite diversity and characteristics in relation to host features. To advance these goals,the investigators will organize three annual workshops composed of experts from each of thesedisciplines to refine predictions for comparative research, explore methods for examiningecological and evolutionary interactions in host-parasite assemblages, and chart future directionsfor both theoretical and empirical work.