Do Sanitation Improvements Reduce Fecal Contamination of Water, Hands, Food, Soil, and Flies? Evidence from a Cluster-Randomized Controlled Trial in Rural Bangladesh.

Ayşe Ercümen ,Sharmin Islam,Amy J Pickering,Debashis Sen,John M Colford,Laura H Kwong,Stephen P Luby,Pavani K Ram,Mahbubur Rahman,Sarker Masud Parvez,Thomas Clasen,Leanne Unicomb,Claire Chase,Andrew Mertens,Benjamin F Arnold,Alan Hubbard ,Mohammad Murshid Alam ,Jade Benjamin‐Chung ,Mijanur Rahman ,Craig Phillip Kullmann ,Raju Ahmed

doi:10.1021/acs.est.8b02988

Abstract

Sanitation improvements have had limited effectiveness in reducing the spread of fecal pathogens into the environment. We conducted environmental measurements within a randomized controlled trial in Bangladesh that implemented individual and combined water treatment, sanitation, handwashing (WSH) and nutrition interventions (WASH Benefits, NCT01590095). Following approximately 4 months of intervention, we enrolled households in the trial’s control, sanitation and combined WSH arms to assess whether sanitation improvements, alone and coupled with water treatment and handwashing, reduce fecal contamination in the domestic environment. We quantified fecal indicator bacteria in samples of drinking and ambient waters, child hands, food given to young children, courtyard soil and flies. In the WSH arm, Escherichia coli prevalence in stored drinking water was reduced by 62% (prevalence ratio = 0.38 (0.32, 0.44)) and E. coli concentration by 1-log (Δlog10 = −0.88 (−1.01, −0.75)). The interventions did not reduce E. coli along other sampled pathways. Ambient contamination remained high among intervention households. Potential reasons include noncommunity-level sanitation coverage, child open defecation, animal fecal sources, or naturalized E. coli in the environment. Future studies should explore potential threshold effects of different levels of community sanitation coverage on environmental contamination.

Highlights

Diarrheal disease, intestinal parasites, and subclinical enteric infections are transmitted through environmentally mediated pathways,[1,2] which can be interrupted by water, sanitation and hygiene interventions
Sanitation as a “primary barrier” isolates fecal matter from the environment to prevent the spread of fecal pathogens and reduce fly breeding sites
In the three study arms selected for the environmental assessment, field staff from the International Centre for Diarrhoeal Disease Research, Bangladesh trained for this study conducted household visits to assess indicators of household water, sanitation and hygiene practices through spot-check observations and a structured questionnaire. They collected samples of source and stored drinking water, ambient water from ponds adjacent to enrolled households and used for bathing and domestic chores, hand rinses from index children, food given to young children, courtyard soil and flies captured near the kitchen to quantify fecal indicator bacteria in the domestic environment (Figure 1)

Summary

Introduction

Intestinal parasites, and subclinical enteric infections are transmitted through environmentally mediated pathways,[1,2] which can be interrupted by water, sanitation and hygiene interventions. They collected samples of source and stored drinking water, ambient water from ponds adjacent to enrolled households and used for bathing and domestic chores, hand rinses from index children, food given to young children, courtyard soil and flies captured near the kitchen to quantify fecal indicator bacteria in the domestic environment (Figure 1).

Results

Conclusion