Environmental sampling of Leptospira species to link to human leptospirosis cases

描述(申请人提供)：钩端螺旋体病是一种常见的人畜共患病，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，有超过10%的病例死亡。尽管疾病无处不在，疾病的发病率也很高，但关于环境循环和向人类传播的情况仍有许多未知之处。致病性钩端螺旋体细菌从哺乳动物宿主的尿液排放到环境中时会污染环境。人类经常因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，已记录了与水接触的钩端螺旋体病病例，几乎没有疑似钩端螺旋体污染，这表明需要确定影响钩端螺旋体持续和传播的其他潜在重要因素。家畜、宠物和牙周炎大鼠以及天气模式被认为在环境循环中发挥重要作用，并与人类钩端螺旋体病相关，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，可以减少钩端螺旋体病的病例数量。这项研究将在厄瓜多尔波托维耶霍市附近进行，那里钩端螺旋体病病例很常见，将涉及环境、动物和临床样本的收集和分析。这一提议的中心假设是，对人类传播来说，特定来源比其他来源更重要。检验这一假设将涉及到解决两个具体目标。第一个是随着时间的推移跟踪致病性钩端螺旋体的环境负荷，并寻找生物和非生物的相关性。由于钩端螺旋体病是通过水传播的， 样本将从波托维耶霍附近的两条大河中采集。将获得采样点和样本的物理性质，并将通过实时PCR分析来量化致病性钩端螺旋体的载量。每个样本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分型与临床基因分型联系起来。将收集临床样本，对其进行基因分型，并与从牲畜、老鼠和河流样本中收集的样本进行基因分型比较。这些样本来源是钩端螺旋体病感染的最重要已知来源，因此提供了将环境和动物基因与人类疾病联系起来的独特机会。

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.