Effects of Single and Combined Water, Sanitation and Handwashing Interventions on Fecal Contamination in the Domestic Environment: A Cluster-Randomized Controlled Trial in Rural Bangladesh

Abstract

Water, sanitation, and hygiene interventions have varying effectiveness in reducing fecal contamination in the domestic environment; delivering them in combination could yield synergies. We conducted environmental assessments within a randomized controlled trial in Bangladesh that implemented single and combined water treatment, sanitation, handwashing (WSH) and nutrition interventions (WASH Benefits, NCT01590095). After one and two years of intervention, we quantified fecal indicator bacteria in samples of drinking water (from source or storage), child hands, children’s food and sentinel objects. In households receiving single water treatment interventions, Escherichia coli prevalence in stored drinking water was reduced by 50% and concentration by 1-log. E. coli prevalence in food was reduced by 30% and concentration by 0.5-log in households receiving single water treatment and handwashing interventions. Combined WSH did not reduce fecal contamination more effectively than its components. Interventions did not reduce E. coli in groundwater, on child hands and on objects. These findings suggest that WSH improvements reduced contamination along the direct transmission pathways of stored water and food but not along indirect upstream pathways. Our findings support implementing water treatment and handwashing to reduce fecal exposure through water and food but provide no evidence that combining interventions further reduces exposure.

Effects of improved water, sanitation, and hygiene and improved complementary feeding on environmental enteric dysfunction in children in rural Zimbabwe: A cluster-randomized controlled trial

“…By contrast, WASH Benefits Bangladesh [43] reported that children in all intervention groups had lower intestinal permeability (lactulose and mannitol) and inflammation (neopterin) at age 3 months compared to the control group. Diarrhoea prevalence, E.coli contamination of water, and Giardia duodenalis prevalence were also reduced in this trial [77,78], which is consistent with the hypothesis that EED is caused by environmental exposure to enteric pathogens. However, by age 28 months markers of intestinal permeability (A1AT and lactulose excretion) and inflammation (myeloperoxidase) were increased in the WASH and nutrition arms, making the impact of the trial interventions difficult to ascertain.…”

“…This study also reported significant improvements in access to piped water. There was no impact on soiltransmitted helminth infections, and other indicators of enteric pathogen exposure were not reported [78]. The impact of nutritional interventions have also been inconsistent [19,22,26,27,30,80].…”

The WASH Benefits and SHINE trials: interpretation of WASH intervention effects on linear growth and diarrhoea

“…In the WASH Benefits Bangladesh trial, the combined WASH and water chlorination interventions reduced the prevalence of Escherichia coli in stored drinking water and in food, but about 50% of the stored drinking water and 40% of the food still had detectable E coli, and none of the WASH interventions reduced E coli on the caregivers' or children's hands, ambient water, courtyard soil, or sentinel toys. 46,47 The combined WASH and handwashing interventions significantly reduced Giardia infection by 25%; however, 26-30% of children who received those WASH interventions were still infected with Giardia. 35 The combined WASH and water chlorination interventions reduced hookworm infection by 29-33%, but about 6% of children who received those WASH interventions were still infected with hookworm.…”

Microbial Indicators of Fecal Pollution: Recent Progress and Challenges in Assessing Water Quality

“…Routine monitoring of surface waters is widely conducted in order to assess regulatory compliance, characterize water quality trends, and provide timely warnings to protect public health [ 184 – 189 ]. Specific investigations, often supplemented with historical monitoring data, may be conducted to inform management strategies and remediation efforts and to evaluate the impacts of infrastructure, policy, and practices [ 59 , 118 •, 179 , 190 – 193 ]. Forensic applications are increasingly pursued to assign responsibility for fecal pollution, largely enabled by wider adoption of MST approaches and molecular detection methods [ 13 , 69 , 70 , 106 , 117 •, 120 , 123 ].…”