Evolutonary Mechanisms of RNA Virus Host Switching

7.项目总结 广泛的长期目标：这里所述的研究目标，以及在未来的研究中 将在这些发现的基础上，寻求揭示机制中的一般科学原理 这推动了人畜共患核糖核酸病毒的“溢出”和适应。 重要意义：在所有人类传染性疾病中，超过一半是由RNA病毒引起的 起源于人畜共患病。野生动物研究，以形成对RNA病毒的完整了解- 宿主相互作用，特别是直接测试生态压力对病毒影响的那些 在接触期间传播和在溢出期间病毒的第一个适应步骤可以提供 重要的见解。具体地说，研究汉坦病毒的出现和适应可以 为以下方面提供关键数据：(1)预测RNA病毒出现和缓解的模型；(2) 确定用于治疗干预的病毒和宿主目标；以及(3)基本了解 调节病毒-宿主相互作用和病毒基因变异的选择压力。 具体目标：我们建议使用南美汉坦病毒进行现场和实验室研究 一个测试特定选择压力以揭示RNA进化机制的模型系统 病毒在水库(HR)和溢出宿主(HS)宿主系统中的适应。提出的三个目标 将：(1)确定宿主水库和共生地区啮齿动物物种中的病毒出现 外在(环境)压力；(2)揭示外在(环境)与 生态)对野生啮齿动物种群原有宿主内遗传变异的压力；以及， (3)确定病毒在体外适应新寄主物种时的适合度、毒力和基因型别。 研究设计和方法：目标1的拟议现场选址位于巴拉圭东部， 两个汉坦病毒共同传播，以及汉坦病毒血清阳性率水平升高 与土地利用的人为变化有关。我们建议评估以下方面的影响：(1) 增加食物资源和(2)减少对病毒流行的掠夺(目标1)和 原生林区和受干扰林区啮齿动物寄主间遗传变异(目标2)。在《目标3》中， 我们关注这些病毒的适合性和毒性，以及导致 适应。使用基于原代内皮细胞培养的方法，我们将定义 当一种新的寄主物种HS与病毒相互作用时，产生固有的(宿主)选择压力 当它复制时，会适应新的主机。

7. Project Summary Broad, long-term objectives: The research objectives stated herein, and in future studies that would build upon these findings, seek to reveal general scientific principles in the mechanisms that drive "spillover" and adaption of zoonotic RNA viruses. Significance: RNA viruses contribute to more than half of all human infectious diseases that have originated as zoonoses. Wildlife studies to form a complete understanding of RNA viral- host interactions, especially those that directly test the impact of ecological pressures on viral spread during contact and the first adaptive steps of the virus during spillover can provide important insights. Specifically, the study of the emergence and adaption of hantaviruses can provide critical data for: (1) models for prediction of RNA viral emergence and mitigation; (2) identification of viral and host targets for therapeutic intervention; and (3) a basic understanding of the selective pressures that modulate viral-host interactions and viral genetic variation. Specific aims: We propose field and laboratory studies using South American hantaviruses as a model system to test specific selective pressures to reveal evolutionary mechanisms of RNA virus adaption in reservoir (HR) and spillover host (HS) host systems. The three Aims proposed will: (1) define viral emergence within host reservoirs and sympatric rodent species during extrinsic (environmental) pressure; (2) reveal the relationship of extrinsic (environment & ecological) pressures on preexisting intrahost genetic variation in wild rodent populations; and, (3) define viral fitness, virulence, and genotype during adaptation to new host species in vitro. Research design and methods: The proposed field site for Aim 1 lies in eastern Paraguay, where two hantaviruses co-circulate, and where elevated seroprevalence levels of hantaviruses are associated with anthropogenic alteration of land use. We propose to assess effects of: (1) increased food resources and (2) reduced predation on virus prevalence (Aim 1) and intra- and interhost genetic variation in rodents within native and disturbed forest areas (Aim 2). In Aim 3, we focus on the fitness and virulence of these viruses and the genetic changes that lead to adaptation. Using primary endothelial cell culture-based approaches, we will define the impact of intrinsic (host) selective pressures occurring when a new host species, HS, interacts with virus as it replicates, adapts to a new host host.