Steinbaum Lauren, Njenga Sammy M, Kihara Jimmy, Boehm Alexandria B, Davis Jennifer, Null Clair, Pickering Amy J
Civil and Environmental Engineering, Stanford University, Stanford, California, United States of America.
Eastern and Southern Africa Center of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
PLoS One. 2016 Jun 24;11(6):e0157780. doi: 10.1371/journal.pone.0157780. eCollection 2016.
Almost one-quarter of the world's population is infected with soil-transmitted helminths (STH). We conducted a study to determine the prevalence and location of STH-Ascaris, Trichuris, and hookworm spp.-egg contamination in soil within rural household plots in Kenya. Field staff collected soil samples from July to September 2014 from the house entrance and the latrine entrance of households in Kakamega County; additional spatial sampling was conducted at a subset of households (N = 22 samples from 3 households). We analyzed soil samples using a modified version of the US Environmental Protection Agency (EPA) method for enumerating Ascaris in biosolids. We found 26.8% of households had one or more species of STH eggs present in the soil in at least one household location (n = 18 out of 67 households), and Ascaris was the most commonly detected STH (19.4%, n = 13 out of 67 households). Prevalence of STH eggs in soil was equally likely at the house entrance (19.4%, N = 67) as at the latrine entrance (11.3%, N = 62) (p = 0.41). We also detected STH eggs at bathing and food preparation areas in the three houses revisited for additional spatial sampling, indicating STH exposure can occur at multiple sites within a household plot, not just near the latrine. The highest concentration of eggs in one house occurred in the child's play area. Our findings suggest interventions to limit child exposure to household soil could complement other STH control strategies.
世界上近四分之一的人口感染了土源性蠕虫（STH）。我们开展了一项研究，以确定肯尼亚农村家庭地块土壤中土源性蠕虫——蛔虫、鞭虫和钩虫属——虫卵污染的流行情况及位置。2014年7月至9月，现场工作人员从卡卡梅加县各家庭的房屋入口和厕所入口采集土壤样本；对部分家庭进行了额外的空间采样（从3户家庭采集了22份样本）。我们使用美国环境保护局（EPA）用于在生物固体中计数蛔虫的方法的改良版来分析土壤样本。我们发现，26.8%的家庭在至少一个家庭位置的土壤中存在一种或多种土源性蠕虫虫卵（67户家庭中有18户），蛔虫是最常检测到的土源性蠕虫（19.4%，67户家庭中有13户）。房屋入口处土壤中土源性蠕虫虫卵的流行率（19.4%，N = 67）与厕所入口处（11.3%，N = 62）相当（p = 0.41）。在重新进行额外空间采样的3户房屋的沐浴和食物制备区域，我们也检测到了土源性蠕虫虫卵，这表明土源性蠕虫暴露可能发生在家庭地块内的多个地点，而不仅仅是厕所附近。一所房屋中虫卵浓度最高的地方出现在儿童游乐区。我们的研究结果表明，限制儿童接触家庭土壤的干预措施可以补充其他土源性蠕虫控制策略。
