Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Department of Environmental Sciences and Engineering, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
Environ Sci Technol. 2021 Feb 2;55(3):1941-1952. doi: 10.1021/acs.est.0c06972. Epub 2021 Jan 20.
Rigorous studies of water, sanitation, and hygiene interventions in low- and middle-income countries (LMICs) suggest that children are exposed to enteric pathogens via multiple interacting pathways, including soil ingestion. In 30 compounds (household clusters) in low-income urban Maputo, Mozambique, we cultured and quantified gene targets from soils (: , / (EIEC): , : ) using droplet digital PCR at three compound locations (latrine entrance, solid waste area, dishwashing area). We found that 88% of samples were positive for culturable (mean = 3.2 log CFUs per gram of dry soil), 100% for molecular (mean = 5.9 log gene copies per gram of dry soil), 44% for (mean = 2.5 log), and 41% for (mean = 2.1 log). Performing stochastic quantitative microbial risk assessment using soil ingestion parameters from an LMIC setting for children 12-23 months old, we estimated that the median annual infection risk by was 7100-fold (71% annual infection risk) and by /EIEC was 4000-fold (40% annual infection risk) greater than the EPA's standard for drinking water. Compounds in Maputo, and similar settings, require contact and source control strategies to reduce the ingestion of contaminated soil and achieve acceptable levels of risk.
在低收入和中等收入国家（LMICs）中，对水、环境卫生和个人卫生干预措施的严格研究表明，儿童通过多种相互作用的途径接触肠道病原体，包括吞食土壤。在莫桑比克低收入城市马普托的 30 个化合物（家庭集群）中，我们使用液滴数字 PCR 在三个化合物位置（厕所入口、固体废物区、洗碗区）培养并量化了土壤中的基因靶标（:, / (EIEC):, : ）。我们发现，88%的样本可培养出（平均每克干土 3.2log CFUs），100%的样本可检测到分子（平均每克干土 5.9log 基因拷贝），44%的样本可检测到（平均每克干土 2.5log），41%的样本可检测到（平均每克干土 2.1log）。使用来自 LMIC 环境中 12-23 个月大儿童的土壤摄取参数进行随机定量微生物风险评估，我们估计，由引起的年平均感染风险中位数为 7100 倍（71%的年感染风险），由 /EIEC 引起的年平均感染风险中位数为 4000 倍（40%的年感染风险）高于 EPA 对饮用水的标准。马普托和类似环境中的化合物需要采取接触和源头控制策略，以减少受污染土壤的摄入并达到可接受的风险水平。
