Abstract

Water, sanitation and hygiene (WASH) interventions have been advocated as important complements to deworming programs to improve soil-transmitted helminth (STH) control. Evidence for the impact of WASH on STH is mixed, and based mainly on cross-sectional studies. In this study, we assessed associations between individual- and household-level WASH variables and STH infections, using data collected during the 2 year follow-up study period of the WASH for WORMS randomised controlled trial in Timor-Leste. Data were collected across four surveys, conducted at 6 monthly intervals in 23 communities. We analysed WASH and sociodemographic variables as risk factors for infection with Necator americanus, Ascaris spp., and undifferentiated STH infection, using generalised linear mixed models to account for clustering at community, household and participant levels. WASH risk factors were examined both concurrently and with a 6 month lag period that coincided with the most recent deworming. The analysis included 2333 participants. Factors associated with N. americanus infection included age group, male sex (adjusted odds ratio (aOR) 3.1, 95% confidence interval (CI) 2.4-4.2), working as a farmer (aOR 1.7, 95% CI 1.2-2.4), and completing secondary school or higher (aOR 0.29, 95% CI 0.16-0.53). Risk factors for Ascaris spp. infection included age group, living in a dwelling with more than six people (aOR 1.6, 95% CI 1.1-2.3), having a tube well or borehole as the household water source (aOR 3.7, 95% CI 1.3-10.8), and using a latrine shared between households 6 months previously (aOR 2.3, 95% CI 1.2-4.3). Handwashing before eating was protective against infection with any STH (aOR 0.79, 95% CI 0.65-0.95). In the context of regular deworming, few WASH-related factors were associated with STH infections. Future research examining the role of WASH in STH transmission is required, particularly in low transmission settings after cessation of deworming. Identifying improved indicators for measuring WASH-related behaviours is also a key priority.

Authors	V Nery, Susana; Clarke, Naomi E; Richardson, Alice; Traub, Rebecca; McCarthy, James S; Gray, Darren J; Vallely, Andrew J; Williams, Gail M; Andrews, Ross M; Campbell, Suzy J; C A Clements, Archie
Journal	INTERNATIONAL JOURNAL FOR PARASITOLOGY
Pages	389-396
Volume	49
Date	1/02/2019
Grant ID	1013713
Funding Body	National Health and Medical Research Council (NHMRC; Australia)
URL	http://www.ncbi.nlm.nih.gov/pubmed/?term=10.1016/j.ijpara.2018.12.006