EAGER: Disentangling how community composition differentially acts on multiple determinants of transmission in a directly-transmitted zoonotic pathogen

生物多样性正在以惊人的速度消失，与此同时，传染病越来越多地从野生动物蔓延到人类。因此，迫切需要了解生物多样性如何影响野生动物的传染病。在一些生态系统中，更多样化的群落降低了疾病风险，这被称为“稀释”效应，因为生物多样性稀释了感染。然而，在其他系统中，更多样化的社区增加了疾病风险，称为“放大”效应。何时期望稀释或放大是疾病生态学家争论的话题。本项目旨在利用鹿小鼠体内的辛诺布雷汉坦病毒（SNV）作为模型，协调生物多样性对疾病风险的竞争效应，该模型同时显示了在同一系统中稀释和扩增的两个方面。研究人员将通过研究潜在的机制来研究生物多样性如何产生竞争效应，特别是鹿鼠和群落中其他物种之间的竞争如何影响疾病动态。这项研究将有助于统一稀释与放大理论。它还将促进汉坦病毒肺综合征（HPS）的预防工作，从而造福社会。自1993年发现汉坦病毒肺综合征以来，已有700多人感染（250多人死亡）。HPS不成比例地影响了美洲原住民，他们将参与部落土地的研究。这个项目将测试鹿鼠和其他小型哺乳动物竞争者之间的竞争会影响宿主密度、宿主之间的接触率以及在它们之间接触的情况下从受感染宿主向未受感染宿主传播的可能性的假设。根据以往的观察性研究，SNV表现出整体稀释效应，即随着小哺乳动物多样性的增加，鹿鼠密度的减少，但也表现出部分放大效应，即传播率的增加（给定宿主密度的接触率与给定接触的传播概率的乘积）。在这里，研究人员将测试鹿鼠和其他小型哺乳动物之间的竞争是否驱动了这两种观察到的模式。目标1将使用长期种群数据的贝叶斯分析来确定鹿鼠密度的下降是由于竞争还是多样性、栖息地类型或环境条件的其他方面。目标2将通过实验确定竞争的增加是否会导致压力和免疫力下降和/或行为和接触率的变化（这会影响传播率）。在封闭环境中控制鹿鼠和竞争对手的密度，并进行接触、应激和免疫测量。此外，将监测未受操纵的自然种群的动态，以扩大实验研究的解释。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Biodiversity is disappearing at an alarming rate, and at the same time, infectious diseases increasingly spill over from wildlife to humans. Therefore, it is urgent to understand how biodiversity affects infectious diseases in wildlife. In some ecosystems, a more diverse community decreases disease risk, termed the 'dilution' effect because biodiversity dilutes out infection. However, in other systems, a more diverse community increases disease risk, termed the 'amplification' effect. When to expect dilution or amplification is a topic of debate among disease ecologists. This project aims to reconcile the competing effects of biodiversity on disease risk using Sin Nombre hantavirus (SNV) in deer mice as a model, which displays aspects of both dilution and amplification in the same system at the same time. Researchers will examine how biodiversity can have competing effects by examining the underlying mechanisms, especially how competition between deer mice and other species in the community affects disease dynamics. This research will help unify the theories of dilution vs. amplification. It will also benefit society by advancing prevention efforts for hantavirus pulmonary syndrome (HPS), which has infected more than 700 people (and killed more than 250) since its discovery in 1993. HPS has disproportionately affected Native Americans, who will be involved in this research on tribal lands. This project will test the hypothesis that competition between deer mice and other small mammal competitors affects host density, contact rates among hosts, and the probability of transmission from an infected to an uninfected host given contact between them. Based on previous observational studies, SNV displays an overall dilution effect through a decrease in deer mouse density with increased small mammal diversity, but also a component amplification effect through an increase in the transmission rate (a product of the contact rate for a given host density and the probability of transmission given contact). Here, researchers will test whether competition between deer mice and other small mammals drives both of these observed patterns. Aim 1 will determine if the decrease in deer mouse density is a result of competition or some other aspect of diversity, habitat type, or environmental conditions, using Bayesian analysis of long-term population data. Aim 2 will determine experimentally if an increase in competition leads to stress and depressed immunity and/or changes in behavior and contact rates (which affect the transmission rate). Deer mouse and competitor density will be manipulated in enclosures and contacts, stress, and immunity measured. Additionally, dynamics in an unmanipulated natural population will be monitored to expand interpretation of the experimental study.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.