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Population Genetic Structure of Ixodes scapularis and disease transmission

肩胛硬蜱的种群遗传结构与疾病传播

基本信息

批准号：
9087143
负责人：
Ivan Castro-Arellano
金额：
$ 16.92万
依托单位：
TEXAS A&M AGRILIFE RESEARCH
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-06-15 至 2018-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9087143
关键词：
Affect Animal Diseases Animals Area Arthropod Vectors Arthropods Bite Black-legged Tick Borrelia burgdorferi Case Study Centers for Disease Control and Prevention (U.S.)Collection Communities Competence Complex Contracts Data Disease Ecology Environment Genetic Genetic Drift Genetic Variation Geographic Distribution Geographic Locations Geography Goals Habitats Health Human Incidence Individual Infection Insecta Ixodes Judgment Lyme Disease Mammals Measurement Midwestern United States Mites Modeling Modification Molecular Other Genetics Parasites Pattern Plants Population Population Genetics Population Study Practice Management Prevalence Preventive Preventive measure Regional Disease Research Research Project Grants Resolution Risk Risk Assessment Role Structure Testing Texas Tick-Borne Diseases Ticks Time United States Variant Vector-transmitted infectious disease anthropogenesis base disease transmission disorder risk expectation experience feeding improved insight pathogen population genetic structure pressure reproductive spatial temporal variation trait transmission process vector

项目摘要

DESCRIPTION (provided by applicant): The long-term goal of this research project is to improve our understanding of Lyme disease (LD) transmission through the study of the population genetics of the arthropod vector in the Southern US. This integrated ecological approach will provide significant information on the competence of I. scapularis as a B. burgdorferi vector when feeding from different vertebrate host-species. By capitalizing on the ecological variation among geo-climatically distinct regions in Texas, this study will provide both an ecological and genetic framework to characterize the transmission of LD to humans in the South-Central United States. LD is the most prevalent arthropod-borne disease in the US with 33,097 cases reported to the CDC during 2011. Almost all LD studies completed to date are focused in the Northeast and Midwest regions of the US where this disease is more prevalent, with no major studies done in Southern US. There is a critical need to determine the ecological factors promoting the differential incidence of LD even though the agent, vector and mammalian hosts are present in both geographic regions. In addition, there is limited information on the genetic diversity of I. scapularis and on the role this genetic diversity has in explaining the ris of contracting LD. We will use recent insights into the host use ecology and genetics of other tick species as a baseline to explore if the same phenomenon occurs in I. scapularis. Host availability, diversity and abundance vary across both spatial and temporal scales. Therefore, individuals of a given vector species may be subjected to distinct selective pressures in different geographic portions of its distribution. This may result in vector populations being structured by geography, host species or a combination of both. At its most basic level, understanding patterns of spatial variation in host use by polyphagous vectors of animal diseases, requires the collection of host use data at both fine and course resolutions. Consequently, we will approach this issue by proposing two specific aims. Specific Aim 1: Quantify local host use patterns and B. burgdorferi infection in Ixodes scapularis in two contrasting environments in Texas (Pinewoods and Post Oak Savannah) within the geographic distribution of I. scapularis. We will also test for differences of vertebrate host communities, tick prevalence and B. burgdorferi infection between anthropogenically degraded and sylvan habitats at the selected Texas eco- regions. (Dr. Esteve-Gassent, Dr. Castro-Arellano). Specific Aim 2: We will test for genetic population structure and host associated genetic differentiation of I. scapularis across the different eco-regions outlined above (Dr. Medina). At the completion of these studies, it is our expectation that we will have identified the local host use patterns of I. scapularis, as well as te host associated genetic differences. We also expect to have delineated the distribution of B. burgdorferi in the studied vertebrate hosts and evaluated their competence as reservoirs for this pathogen in the state of Texas.

描述(申请人提供)：这项研究项目的长期目标是通过研究美国南部节肢动物媒介的种群遗传学来提高我们对莱姆病(LD)传播的了解。这种综合的生态学方法将提供重要的信息，即当从不同的脊椎动物寄主物种取食时，肩胛虫作为伯氏假单胞菌媒介的能力。通过利用德克萨斯州不同地理气候地区之间的生态差异，这项研究将提供一个生态和遗传框架，用来描述LD在美国中南部向人类传播的特征。LD是美国最常见的节肢动物传播疾病，2011年向疾控中心报告了33,097例。到目前为止，几乎所有完成的LD研究都集中在这种疾病更普遍的美国东北部和中西部地区，而在美国南部没有进行重大研究。尽管病原体、病媒和哺乳动物宿主都存在于这两个地理区域，但迫切需要确定促进LD不同发病率的生态因素。此外，关于我肩周炎的遗传多样性以及这种遗传多样性在解释感染LD的RIS中所起的作用的信息有限。我们将利用最近对寄主利用生态学和其他扁虱物种的遗传学的洞察力作为基线，来探索同样的现象是否发生在我肩部。寄主可获得性、多样性和丰度在空间和时间尺度上都有所不同。因此，给定媒介物种的个体可能在不同的环境中受到不同的选择压力。其分布的地理部分。这可能会导致媒介种群由地理、宿主物种或两者的组合构成。在最基本的层面上，要了解动物疾病多食性病媒宿主利用的空间变化模式，需要收集精细和过程分辨率的宿主利用数据。因此，我们将通过提出两个具体目标来处理这个问题。具体目标1：在德克萨斯州的两个不同的环境(松树和橡树后萨凡纳)中，量化本地寄主使用模式和伯氏巴氏杆菌在肩部硬蜱中的感染情况。我们还将在选定的德克萨斯州生态区测试人类退化和森林生境之间脊椎动物宿主群落、壁虱流行率和伯氏杆菌感染的差异。(Esteve-Gassent博士、Castro-Arellano博士)。具体目标2：我们将在上面概述的不同生态区测试肩袖轮虫的遗传种群结构和与宿主相关的遗传分化(Medina博士)。在这些研究完成后，我们期望我们能够识别出肩峰斑潜蝇在当地的寄主利用模式，以及与寄主相关的遗传差异。我们还期望描绘出伯氏杆菌在所研究的脊椎动物宿主中的分布，并评估它们作为德克萨斯州这种病原体的宿主的能力。