Human and Animal Fecal Contamination of Community Water Sources, Stored Drinking Water and Hands in Rural India Measured with Validated Microbial Source Tracking Assays.

Alexander Schriewer,Pinaki Panigrahi,Stefan Wuertz,Mitsunori Odagiri,Marion W Jenkins,Pravas R Misra,Thomas Clasen

doi:10.4269/ajtmh.14-0824

Alexander Schriewer, Pinaki Panigrahi + Show 5 more

Open Access

https://doi.org/10.4269/ajtmh.14-0824

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Abstract

We examined pathways of exposure to fecal contamination of human and animal origin in 24 villages in Odisha, India. In a cross-sectional study during the monsoon season, fecal exposure via community water sources (N = 123) and in the home (N = 137) was assessed using human- and nonhuman-associated Bacteroidales microbial source tracking (MST) markers and fecal coliforms (FCs). Detection rates and marker concentrations were examined to pinpoint pathways of human fecal exposure in the public and domestic domains of disease transmission in study communities. Human fecal markers were detected much more frequently in the domestic domain (45% of households) than in public domain sources (8% of ponds; 4% of groundwater drinking sources). Animal fecal markers were widely detected in both domains (74% of ponds, 96% of households, 10% of groundwater drinking sources), indicating ubiquitous risks of exposure to animal feces and zoonotic pathogens. This study confirms an often suggested contamination link from hands to stored water in the home in developing countries separately for mothers' and children's hands and both human and animal fecal contamination. In contrast to MST markers, FCs provided a poor metric to assess risks of exposure to fecal contamination of human origin in this rural setting.

Highlights

Diarrhea is a leading cause of child mortality with significant adverse long-term implications for child development.[1]
Likewise, where zoonotic pathogens contribute to the endemic diarrhea disease burden through exposure to animal excreta,[4] conventional WASH interventions focused on exposure to human excreta alone may have limited health impacts
The detection of fecal bacteria was significantly higher in community ponds (87% for fecal coliforms (FCs), 100% for BacUni) than in improved groundwater drinking sources (49% FC, 56% BacUni) (χ2, P < 0.001 both)

Summary

Introduction

Diarrhea is a leading cause of child mortality with significant adverse long-term implications for child development.[1] Water supply, water quality, sanitation, and hygiene (WASH) are fundamental to reducing fecal-oral transmission of enteric pathogens causing much of the global child diarrhea disease burden.[2] WASH interventions can significantly lower diarrhea risk, the performance of individual components in specific settings is highly variable with no effects sometimes observed.[3] Apart from study methodological and compliance heterogeneity, inconsistent outcomes are plausible if dominant pathways of endemic transmission differ between study sites. Examining fecal contamination across multiple fecal-oral transmission pathways and identifying sources of fecal exposure, for example, whether human or animal, can help pinpoint which routes pose risks to human health.[5] Such understanding can improve selection and design of WASH intervention strategies in a given setting. Knowing whether human fecal exposure is occurring mainly in the public domain, or mainly in the domestic domain has implications for the loci of control over prevention, the geographic extent and number of potential source(s) of pathogens, appropriate roles

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