Understanding the mechanisms of transmission of human leptospirosis in slums settlements in Salvador, Brazil

了解巴西萨尔瓦多贫民窟中人类钩端螺旋体病的传播机制

• 批准号: 2665161
• 金额: --
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2665161
• 关键词: Understanding; mechanisms; transmission; human; leptospirosis

Global health needLeptospirosis, a spirochetal zoonosis, has emerged as an important health problem as slum settlements have expanded rapidly worldwide and created conditions for rat-borne transmission. In Brazil, 12,000 individuals are annually infected with leptospirosis, with a death rate of about 12%. In the city of Salvador, Brazil, where transmission mostly occurs in peridomestic environments, the government-led expansion of closed sewer networks has resulted in a significant decrease of infection rates for leptospirosis. However, due to political neglect and the uncontrolled expansions of slums, construction of conventional governmentally led closed sewer systems (GOV-INT) is increasingly problematic. To address this issue, innovative and more economical methods that require of community residents involvement (COM-INT) have emerged as suitable alternatives to improve sanitation in slum settlements. However, assessing the real impact of sanitation intervention, such as GOV-INT and COM-INT, is problematic because of methodological issues due to confounding factors and difficulties with randomization of the population to obtain large enough large sample sizes.Current knowledge gapsTo the best of our knowledge, no study has been carried out to assess the potentially positive effects of COM-INT on the reduction of leptospirosis risk. Based on preliminary descriptive statistics from an ongoing study in Salvador, to which this project directly contributes, it has been conjectured that GOV-INT and COM-IN are equally effective in the reduction of Leptospirosis infections. In this context, the use of spatio-temporal statistical methods are crucial in order to infer the actual impact of COM-INT by taking account of both measured and unmeasured risk factors of Leptospirosis infection. Study aims1. Determine the mechanisms by which COM-INT and GOV-INT reduce direct human contact with sewage and environmental pathogen load in urban slums.2. Determine the contribution of COM-INT and GOV-INT on a decline in severe disease incidence in a large urban center.Study design/methodologyAs part of a Wellcome-Trust project, this study will be split into the following two parts (each referring to the above aims in turn)1. The main cause of Leptospira infection is exposure to contaminated sewage and run-off. Hence, to pursue the first study aim, statistical methods that combine information from environmental reservoirs and resident's movement will be fitted to data from an ongoing study in the community of Marechal Rodon in Salvador, Brazil. This study site consists of 9 areas, 3 with GOV-INT, 3 with COM-INT and 3 with no intervention. A total of 2,582 soils samples will be collected and tested for Leptospira DNA, before and after the interventions. These data will be integrated with human mobility data collected on 150 individuals using multifunctional sensor nodes to quantity the exposure to contamination sources2. A secondary spatio-temporal geostatistical analysis will be conducted to assess the effectiveness of COM-INT and GOV-INT, using data collected since 1996 from a hospital-based surveillance for leptospirosis that covers the population of Salvador since. To account for confounding effects, information on socio-economic and environmental factors will also be incorporated into the spatio-temporal model.

全球卫生需要钩端螺旋体病是一种人畜共患螺旋体病，随着贫民窟在全世界迅速扩大，并为鼠媒传播创造了条件，钩端螺旋体病已成为一个重要的卫生问题。在巴西，每年有12，000人感染钩端螺旋体病，死亡率约为12%。在巴西的萨尔瓦多市，传播主要发生在居住区周围环境中，政府主导的封闭下水道网络的扩建导致钩端螺旋体病感染率显著下降。然而，由于政治上的忽视和贫民窟的不受控制的扩张，传统的政府主导的封闭式下水道系统（GOV-INT）的建设越来越成问题。为了解决这个问题，需要社区居民参与的创新和更经济的方法（COM-INT）已经成为改善贫民窟居住区卫生设施的合适替代方案。然而，评估卫生干预措施的真实的影响，如GOV-INT和COM-INT，是有问题的，因为方法问题，由于混杂因素和困难与随机化的人口，以获得足够大的大样本sizes.Current知识gapsTo我们所知，没有研究已经进行了评估潜在的积极影响COM-INT对减少钩端螺旋体病的风险。根据在萨尔瓦多进行的一项研究的初步描述性统计数据（该项目直接参与了该研究），证实GOV-INT和COM-IN在减少钩端螺旋体感染方面同样有效。在这种情况下，时空统计方法的使用是至关重要的，以推断COM-INT的实际影响，同时考虑到测量和未测量的钩端螺旋体感染的风险因素。学习目标1.确定COM-INT和GOV-INT减少城市贫民窟中人类与污水和环境病原体负荷的直接接触的机制。研究设计/方法作为Wellcome-Trust项目的一部分，本研究将分为以下两个部分（每个部分依次涉及上述目标）1.钩端螺旋体感染的主要原因是接触受污染的污水和径流。因此，追求的第一个研究目标，统计方法，结合联合收割机的信息，从环境水库和居民的运动将适合从一个正在进行的研究在社区的Marechal Rodon在萨尔瓦多，巴西的数据。本研究中心包括9个区域，3个区域采用GOV-INT，3个区域采用COM-INT，3个区域无干预。在干预前后，将收集总共2 582个土壤样本，并进行钩端螺旋体DNA检测。这些数据将与使用多功能传感器节点收集的150个人的人类移动数据相结合，以量化污染源的暴露量2。将进行二次时空地统计分析，以评估COM-INT和GOV-INT的有效性，使用自1996年以来从医院钩端螺旋体病监测（涵盖萨尔瓦多人口）收集的数据。为了考虑混杂效应，还将把社会经济和环境因素的信息纳入时空模型。