Environmental sampling of Leptospira species to link to human leptospirosis cases

描述（由申请方提供）：钩端螺旋体病是一种常见的人畜共患疾病，在热带和发展中国家最为流行。全世界每年报告的约350，000例病例中，死亡率超过10%。尽管这种疾病无处不在，发病率很高，但关于环境循环和传播给人类的情况仍然未知。当病原性钩端螺旋体细菌通过哺乳动物宿主的尿液脱落到环境中时，会污染环境。人类常因饮用受污染的水或直接接触受感染的尿液而感染钩端螺旋体病。然而，钩端螺旋体病的情况下，已记录与水接触，几乎没有怀疑钩端螺旋体污染，这表明其他潜在的重要因素影响钩端螺旋体的持久性和传播需要加以确定。牲畜、宠物和围产期老鼠以及天气模式被认为在环境循环中起着重要作用，并与人类钩端螺旋体病有关，但缺乏直接的流行病学联系。这项工作的长期目标是减少 通过更好地了解环境中的钩端螺旋体与人类钩端螺旋体病之间的联系，减少钩端螺旋体病病例的数量。本研究将在钩端螺旋体病病例常见的厄瓜多尔波托维耶霍市周围进行，将涉及环境、动物和临床样本的收集和分析。这一建议的核心假设是，特定来源比其他来源对人类传播更重要。检验这一假设将涉及两个具体目标。第一个是跟踪环境负荷的致病性钩端螺旋体随着时间的推移，并寻找生物和非生物相关。由于细螺旋体病是由水传播的， 将从波托维耶霍附近的两条大河中采集样本。通过真实的实时PCR分析，获得采样点和样本的物理性质，并对致病性钩端螺旋体的载量进行定量。每个样品中的微生物群落将通过使用高通量下一代测序技术的16S rRNA基因调查来表征。第二个具体目标是将环境基因型与临床基因型联系起来。将采集临床样本，进行基因分型，并与从牲畜、大鼠和河流样本中采集的样本的基因型进行比较。这些样本来源代表了最重要的已知钩端螺旋体病感染来源，因此提供了一个独特的机会，将环境和动物基因型与人类疾病联系起来。

DESCRIPTION (provided by applicant): Leptospirosis is a common zoonotic disease most prevalent in the tropics and developing world. Death occurs in over 10% of the ~350,000 cases reported worldwide annually. Despite this ubiquity and incidence of disease, much remains unknown about environmental cycling and transmission to humans. Pathogenic Leptospira bacteria contaminate the environment when shed by urine from mammalian hosts into the environment. Humans often contract leptospirosis from contaminated water or from direct exposure to infected urine. However, cases of leptospirosis have been documented from contact with water with little suspected leptospire contamination, suggesting that other potentially important factors affecting Leptospira persistence and transmission need to be identified. Livestock, pets and peridomestic rats as well as weather patterns are thought to play significant roles in environmental cycling and have been correlated to leptospirosis in humans, but direct epidemiological links are missing. The long-term objective of this work is to reduce the number of leptospirosis cases by better understanding links between Leptospira in the environment and leptospirosis in humans. This study will be conducted around Portoviejo City, Ecuador, where leptospirosis cases are common and will involve collection and analyses of environmental, animal and clinical samples. The central hypothesis of this proposal is that specific sources are more important than others for human transmission. Testing this hypothesis will involve addressing two specific aims. The first is to track environmental loads of pathogenic Leptospira over time and search for biotic and abiotic correlates. As leptospirosis is water borne, samples will be collected from the two large rivers near Portoviejo. Physical properties of sampling sites and samples will be obtained and the load of pathogenic Leptospira will be quantified through real- time PCR analysis. Microbial communities in each sample will be characterized by 16S rRNA gene surveys using high-throughput next-generation sequencing technology. The second specific aim will be to link environmental genotypes to clinical genotypes. Clinical samples will be collected, genotyped and compared to genotypes from samples collected from livestock, rats and river samples. These sample sources represent the most significant known sources of leptospirosis infections and thus provide a unique opportunity to link environmental and animal genotypes to human disease.