Modelling faecal pathogen flows and health risks in urban Bangladesh: Implications for sanitation decision making
Modelling faecal pathogen flows and health risks in urban Bangladesh: Implications for sanitation decision making
复制标题
DOI：
10.1016/j.ijheh.2020.113669
复制
发表时间：
2021-02-09
影响因子：
6
通讯作者：
Willetts, Juliet
中科院分区：
文献类型：
--
作者：
Foster, Tim;Falletta, Jay;Willetts, Juliet
在低收入环境中，粪口感染是疾病负担的主要组成部分，卫生设施不足被视为一个促成因素。然而，证明卫生干预措施的健康影响？特别是在城市地区？事实证明，这是一个挑战，而且支持卫生决策以最大限度地提高健康收益的经验证据有限。本研究旨在开发，应用和验证系统建模方法，通过检查肠道病原体输入，运输和减少各种卫生系统，并估计相应的暴露和公共卫生影响，为城市环境中的卫生基础设施和服务决策提供信息。在孟加拉国达卡的一个低收入地区评估了八种卫生选择方案的健康影响，重点是五种目标病原体（志贺氏菌、霍乱弧菌、伤寒沙门氏菌、诺如病毒GII和贾第虫）。相对于研究地点（24%的化粪池，5%的蓄水池和71%的厕所直接排放到明沟）的卫生基础病例，估计化粪池的全面覆盖可减少残疾调整生命年（DADs）中的疾病负担48？72%，而完全覆盖的公共规模的厌氧折流板反应器，估计减少67？百分之八十一尽管有这些改进，但由于污水排放到明沟，这些系统仍然存在令人担忧的健康风险，特别是当系统管理不善时。其他卫生备选方案，包括使用人工湿地和小口径污水处理系统，表明进一步减少了当地的健康风险，尽管有些方案仍将病原体输出到邻近地区，只是将风险转移到下游社区。该研究揭示了在不同性能条件下不同卫生系统的对数减少值、洪水条件下的病原体流动以及典型的低收入城市环境中的病原体脱落和人类接触的敏感性，并需要进一步的证据。尽管输入参数存在可变性和不确定性，但系统建模可以是一种可行和可定制的方法，用于考虑不同环境下不同卫生选择的相对健康影响，并作为指导城市卫生决策的宝贵工具。
Faecal-oral infections are a major component of the disease burden in low-income contexts, with inadequate sanitation seen as a contributing factor. However, demonstrating health effects of sanitation interventions ? particularly in urban areas ? has proved challenging and there is limited empirical evidence to support sanitation decisions that maximise health gains. This study aimed to develop, apply and validate a systems modelling approach to inform sanitation infrastructure and service decision-making in urban environments by examining enteric pathogen inputs, transport and reduction by various sanitation systems, and estimating corresponding exposure and public health impacts. The health effects of eight sanitation options were assessed in a low-income area in Dhaka, Bangladesh, with a focus on five target pathogens (Shigella, Vibrio cholerae, Salmonella Typhi, norovirus GII and Giardia). Relative to the sanitation base case in the study site (24% septic tanks, 5% holding tanks and 71% toilets discharging directly to open drains), comprehensive coverage of septic tanks was estimated to reduce the disease burden in disability-adjusted life years (DALYs) by 48?72%, while complete coverage of communal scale anaerobic baffled reactors was estimated to reduce DALYs by 67?81%. Despite these improvements, a concerning health risk persists with these systems as a result of effluent discharge to open drains, particularly when the systems are poorly managed. Other sanitation options, including use of constructed wetlands and small bore sewerage, demonstrated further reductions in local health risk, though several still exported pathogens into neighbouring areas, simply transferring risk to downstream communities. The study revealed sensitivity to and a requirement for further evidence on log reduction values for different sanitation systems under varying performance conditions, pathogen flows under flooding conditions as well as pathogen shedding and human exposure in typical low-income urban settings. Notwithstanding variability and uncertainties in input parameters, systems modelling can be a feasible and customisable approach to consider the relative health impact of different sanitation options across various contexts, and stands as a valuable tool to guide urban sanitation decision-making.