Wardell Rebecca, Clements Archie C A, Lal Aparna, Summers David, Llewellyn Stacey, Campbell Suzy J, McCarthy James, Gray Darren J, V Nery Susana
Department of Global Health, Research School of Population Health, College of Medicine, Biology and the Environment, The Australian National University, Canberra, ACT, Australia.
National Centre for Epidemiology and Population Health, Research School of Population Health, College of Medicine, Biology and the Environment, The Australian National University, Canberra, ACT, Australia.
PLoS Negl Trop Dis. 2017 May 10;11(5):e0005565. doi: 10.1371/journal.pntd.0005565. eCollection 2017 May.
In Timor-Leste there have been intermittent and ineffective soil-transmitted helminth (STH) deworming programs since 2004. In a resource-constrained setting, having information on the geographic distribution of STH can aid in prioritising high risk communities for intervention. This study aimed to quantify the environmental risk factors for STH infection and to produce a risk map of STH in Manufahi district, Timor-Leste.
METHODOLOGY/PRINCIPAL FINDINGS: Georeferenced cross-sectional data and stool samples were obtained from 2,194 participants in 606 households in 24 villages in the Manufahi District as part of cross sectional surveys done in the context of the "WASH for Worms" randomised controlled trial. Infection status was determined for Ascaris lumbricoides and Necator americanus using real-time quantitative polymerase chain reaction. Baseline infection data were linked to environmental data obtained for each household. Univariable and multivariable multilevel mixed-effects logistic regression analysis with random effects at the village and household level were conducted, with all models adjusted for age and sex. For A. lumbricoides, being a school-aged child increased the odds of infection, whilst higher temperatures in the coolest quarter of the year, alkaline soils, clay loam/loam soils and woody savannas around households were associated with decreased infection odds. For N. americanus, greater precipitation in the driest month, higher average enhanced vegetation index, age and sandy loam soils increased infection odds, whereas being female and living at higher elevations decreased the odds of infection. Predictive risk maps generated for Manufahi based upon these final models highlight the high predicted risk of N. americanus infection across the district and the more focal nature of A. lumbricoides infection. The predicted risk of any STH infection is high across the entire district.
CONCLUSIONS/SIGNIFICANCE: The widespread predicted risk of any STH infection in 6 to 18 year olds provides strong evidence to support strategies for control across the entire geographical area. As few studies include soil texture and pH in their analysis, this study adds to a growing body of evidence suggesting these factors influence STH infection distribution. This study also further supports that A. lumbricoides prefers acidic soils, highlighting a potential relatively unexplored avenue for control.
ClinicalTrials.gov ACTRN12614000680662.
自2004年以来，东帝汶开展了断断续续且效果不佳的土壤传播蠕虫（STH）驱虫项目。在资源有限的情况下，掌握STH的地理分布信息有助于确定高风险社区进行干预的优先次序。本研究旨在量化STH感染的环境风险因素，并绘制东帝汶马努法希地区的STH风险地图。
方法/主要发现：作为“蠕虫与水、环境卫生和个人卫生”随机对照试验背景下进行的横断面调查的一部分，从马努法希地区24个村庄的606户家庭的2194名参与者那里获取了地理参考横断面数据和粪便样本。使用实时定量聚合酶链反应确定蛔虫和美洲板口线虫的感染状况。基线感染数据与为每个家庭获取的环境数据相关联。进行了单变量和多变量多层次混合效应逻辑回归分析，在村庄和家庭层面设置随机效应，所有模型均根据年龄和性别进行了调整。对于蛔虫，学龄儿童感染几率增加，而一年中最凉爽季度温度较高、土壤呈碱性、粘壤土/壤土以及家庭周围的木本稀树草原与感染几率降低相关。对于美洲板口线虫，最干燥月份降水量增加、平均增强植被指数较高、年龄增长以及砂壤土会增加感染几率，而女性以及居住在海拔较高地区则会降低感染几率。根据这些最终模型为马努法希生成的预测风险地图突出显示了整个地区美洲板口线虫感染的高预测风险以及蛔虫感染更具局部性的特点。整个地区任何STH感染的预测风险都很高。
结论/意义：6至18岁人群中任何STH感染的广泛预测风险为支持在整个地理区域实施控制策略提供了有力证据。由于很少有研究在分析中纳入土壤质地和pH值，本研究增加了越来越多的证据，表明这些因素会影响STH感染分布。本研究还进一步支持蛔虫更喜欢酸性土壤，突出了一个潜在的相对未被探索的控制途径。
ClinicalTrials.gov ACTRN12614000680662
