DISSERTATION RESEARCH: Ecologically variable immunity and its consequences for parasite dynamics

预测疾病流行的研究人员的一个重要目标是了解引起疾病流行的寄生虫如何在宿主群体中传播。在对流行病进行预测时，人们会考虑易感宿主和受感染宿主如何以及何时相互接触，但他们通常不会考虑寄生虫进入宿主体内后会发生什么。然而，宿主和寄生虫之间的宿主内部战斗也可能对疾病传播很重要。这些宿主内部的战斗之所以发生，是因为宿主的身体一直在抵抗和防御寄生虫。在预测疾病动态时考虑这些动态是很重要的，因为并非所有宿主都具有同样的抵御寄生虫和疾病的能力。最终，免疫力较低的宿主更有可能让寄生虫传播。在这个项目中，研究人员将重点研究一种生活在湖泊中的无脊椎动物种群，它们每年都会经历大规模的寄生虫流行。该研究人员将通过将免疫变异如何影响宿主与宿主之间的接触信息结合起来，提高我们对疾病传播的理解。这个项目的结果将帮助科学家更好地理解当寄生虫感染人类、农场动物和野生动物种群时免疫防御的重要性。它还将能够培训一名研究生，并支持旨在鼓励代表性不足的少数民族、女性和低收入的本科生和小学学生参与科学的项目。我们对生态和免疫因素如何在自然种群中相互作用以决定个体感染概率和随后的总体疾病患病率的理解仍然有限。利用模型宿主-寄生虫系统（水蚤宿主和真菌寄生虫），本研究探讨了免疫功能的潜在机制，以及可变免疫对寄生虫传播的影响。具体而言，研究人员将研究环境压力因素（例如资源质量和可用性）如何影响天然水蚤种群的免疫功能的平均水平和变化。然后将对这些人群中高毒性寄生虫的建立和传播进行量化，同时跟踪每个人群的暴露水平和感染成功率。这项研究依赖于来自多个学科的工具，包括生态学、定量生物学、转录组学和免疫学。此外，该项目整合了疾病生态学和生态免疫学的理论，从基因组到个人，再到人口和社区，从各个层面检查疾病过程。

An important goal of researchers who predict disease epidemics is to know how the parasites that cause them move through a population of hosts. In making predictions about epidemics, people consider how and when susceptible and infected hosts come into contact with one another, but they generally do not consider what happens after the parasite gets inside its host. However, the within-host battles between host and parasite could also be important for disease spread. These within-host battles happen because a host's body is constantly resisting and defending against parasites. It is important to consider these dynamics in predicting disease dynamics because not all hosts are equally equipped to fend off parasites and diseases. Ultimately, hosts that have lower immunity are more likely to allow parasites to spread. In this project, the researcher will focus on populations of an invertebrate that lives in lakes in which they experience large parasite epidemics every year. The researcher will improve our understanding of disease spread by incorporating information about how variability in immunity affects it with host-to-host contact information. The results of this project will help scientists better understand the importance of immune defenses when parasites infect humans, farm animals, and wildlife populations. It will also enable the training of a graduate student, and support projects aimed at encouraging underrepresented minority, female and low-income undergraduate and grade school students to be involved in science.Our understanding of how ecological and immunological factors interact in natural populations to determine both an individual's probability of infection and the subsequent overall disease prevalence remains limited. Working with a model host-parasite system (Daphnia host and fungal parasite), this research examines the mechanisms underlying immune function, as well as the consequences of variable immunity for parasite transmission. Specifically, the researcher will examine how environmental stressors (e.g. resource quality and availability) shape natural Daphnia populations' mean levels of and variation in immune function. The establishment and spread of the highly virulent parasite within these populations will then be quantified, while tracking each population's levels of exposure and infection success through time. The research relies on tools from multiple disciplines, including ecology, quantitative biology, transcriptomics, and immunology. Moreover, the project integrates theories from disease ecology and ecological immunology to examine disease processes across scales: from the genome, to the individual, to the population and community.