Soil epidemiology: a new tool for environmental surveillance of soil-transmitted helminth infections in endemic settings.

项目总结 土壤传播蠕虫(STH)感染(肠道蠕虫)影响15亿人 全球范围内。最近来自试验和建模研究的证据表明，社区范围内的群众 有足够覆盖率和依从性的驱虫药物给药(CMDA) 可以消除STH传输。然而，在持续环境传播的环境中 网络卫生覆盖率低，STH卵子的持久环境蓄水池 导致较高的再感染率，并阻碍消除工作的进展。 STH控制程序使用基于人类粪便的方法来评估STH的流行率和 地方病流行环境中的强度。然而，个人粪便采样是昂贵的和后勤的 这很困难，特别是在人类感染率低的情况下。如果从以下地点收集和分析土壤 人类活动频繁的社区中的地点(如家庭入口、集水点、 学校)被确定为与人类粪便诊断一样敏感或更敏感，这 该方法可能代表了一种侵入性更小、成本效益更高的MDA监测工具 计划监测和评估。 这项研究将利用多国群组随机对照试验提供 贝宁和印度一年两次的为期三年的CMDA(DeWorm 3)。审判将收集和分析 通过定量聚合酶链式反应，在最后一轮CMDA24个月后(总共8万份)采集人类粪便样本， 这将产生研究地区高度准确的人类STH感染流行率估计。 通过在印度和贝宁的广泛实验室研究和现场测试，我们的团队已经 建立一种灵敏、特异的检测STH环境DNA的分子方法 (埃德娜)在大量的土壤中。我们将在同一时间点在试验范围内嵌套土壤样本 作为人类粪便收集和一年后的具体目标：1)量化 一年两次的CMDA干预对土壤STH水库的影响；2)确定土壤STH EDNA 水平可以预测社区水平的人类STH感染流行；以及3)制定最佳的 土壤采样策略，并将成本与基于人类粪便的监测进行比较。 已将土壤STH EDNA评估与人类感染流行数据配对 DeWorm3试验收集的数据是一个独特且对时间敏感的机会，可以验证和 测试环境性传播疾病监测的效用。我们的发现还将有助于 了解MDA计划与改善的卫生设施相结合的条件 需要采取干预措施，持续降低性传播感染流行率。

PROJECT SUMMARY Soil-transmitted helminth (STH) infections (intestinal worms) affect 1.5 billion individuals globally. Recent evidence from trials and modeling studies suggests that community-wide mass drug administration (cMDA) of deworming medication with sufficient coverage and adherence can eliminate STH transmission. However, in settings with ongoing environmental transmission and low coverage of networked sanitation, persistent environmental reservoirs of STH eggs result in high reinfection rates, and hinder progress towards elimination. STH control programs use human stool-based methods to assess STH prevalence and intensity in endemic settings. However, individual stool sampling is expensive and logistically difficult, particularly when human infection prevalence is low. If collecting and analyzing soil from locations in communities with high human activity (e.g. home entrances, water collection points, schools) were established to be equally or more sensitive than human stool diagnostics, this approach may represent a less invasive and more cost-effective surveillance tool for MDA program monitoring and evaluation. This study will leverage a multi-country cluster-randomized controlled trial delivering three-years of biannual cMDA in Benin and India (DeWorm3). The trial will collect and analyze by qPCR, human stool samples 24 months (n=80,000 in total) after the final round of cMDA, which will yield highly accurate human STH infection prevalence estimates in the study areas. Through extensive laboratory studies and field testing in India and Benin, our team has developed a sensitive and specific molecular method for detecting STH environmental DNA (eDNA) in large volumes of soil. We will nest soil sampling within the trial at the same time point as human stool collection and one year later with the specific aims to: 1) Quantify the effect of a biannual cMDA intervention on the soil STH reservoir; 2) Determine whether soil STH eDNA levels can predict community-level human STH infection prevalence; and 3) Develop the optimal soil sampling strategy and compare costs to human stool-based surveillance. Pairing soil STH eDNA assessments with human infection prevalence data already being collected by the DeWorm3 trial is a unique and time sensitive opportunity to validate and test the utility of environmental STH surveillance. Our findings will also contribute to understanding the conditions under which MDA program integration with improved sanitation interventions is needed for achieving sustained reductions in STH infection prevalence.