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重要组成部分，对自然种群有重要影响。宿主-寄生虫生态学的一个核心问题是宿主行为、生活史和环境的哪些特征能最好地解释传染病的多样性和进化。重要的理论进展提高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观察到的病原体多样性和特征变化背后的生态变量。该项目将研究三目哺乳动物的寄生虫多样性模式，以明确验证流行病学模型和岛屿生物地理学理论得出的预测。本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类型和多样性变化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)寄主的进化多样化是否与寄生虫物种丰富度模式相关？(4)了解寄生虫多样性对野生动物保护有重要意义吗？建立感染野生哺乳动物的病原体和寄生虫的大型数据库对于进行全面分析至关重要，也是本项目的主要目标。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得很好的群体——食肉动物和有蹄类动物。这些数据库捕获(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）寄生虫传播模式和宿主特异性程度的数据，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，所有的数据将在万维网上免费提供，以便其他科学家可以访问这种劳动的成果。了解寄生虫多样性和特征背后的因素对于管理脆弱的野生动物种群和减轻对人类健康的威胁至关重要。本研究通过研究微型和大型寄生虫的丰富多样性，包括寄生虫特征信息，以及通过评估涉及树拓扑、分支长度和宿主多样化率的系统发育信息，扩展了先前宿主-寄生虫比较工作的范围。分析比较方法将控制采样努力，同时测试多变量，并将评估宿主和寄生虫性状是否与系统发育相关。结合生态学、寄生虫学、流行病学和系统发育比较方法的综合方法对于建立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是至关重要的。为了推进这些目标，研究人员将组织三次由这些学科的专家组成的年度研讨会，以完善比较研究的预测，探索检查宿主-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绘制未来的方向。

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.