BACKGROUND: In rural India, child stunting remains a pressing concern that is being targeted by national flagship programmes. Poor child hygiene and exposure to enteric pathogens are important drivers of child stunting. Enteric pathogens can be transmitted from contaminated faeces to infants via water, food, hands, objects, soil, and flies.
OBJECTIVES: In this study, we compared the infants’ risk of enteric infection from exposure to different faecal transmission pathways, so that hygiene interventions can prioritise efforts towards the most dominant risks for infants.
METHODS: We collected data from 42 households with at least one infant aged 0 to 2 years from the study villages in rural Rajasthan, India. Water samples from drinking and bathing water sources, soil samples from household floors where infants were seen playing, and swabs from infants’ and caregivers’ hands were analysed for faecal indicator bacteria (E. coli). Household observations and data from the literature on exposure assessments were used to determine the infant’s frequency and level of exposure to these different faecal transmission pathways. Published ratios between E. coli and enteric pathogens were used to assess the risk of enteric infection from each different faecal transmission pathway analysed.
RESULTS: The transmission pathways analysed included: Mouthing of own infants’ hands, mouthing caregivers’ hands, direct ingestion of soil from the household floor, drinking household stored water, and involuntary ingestion of surface water during bathing events at local streams. Over 98% of all the samples tested were positive for faecal contamination. All of the surface water samples and household floor soil samples were highly contaminated with faecal bacteria (>2 Log10 CFU/100 mL and/g, respectively), and 93% of the drinking water samples were positive for E. coli (Geomean, SD 2.10±0.76 Log10 CFU/100 mL). Over 90% of the infants’ and caregivers’ hand swabs were contaminated. The direct ingestion of soil was the transmission pathway that posed that highest daily risk of enteric infection to infants, followed by mouthing of own soiled hands. Ingestion of soil posed a 1.4-fold higher infection risk than drinking water. The involuntary ingestion of water while bathing at local streams and mouthing of caregivers’ hands posed smaller infection risks, but still considerable after accumulating over time. After one year, the estimated risk of Campylobacter and enteropathogenic E. coli infection was 100% for all the analysed infection pathways.
CONCLUSIONS: Water, sanitation and hygiene programmes have typically overlooked soil as a faecal exposure pathway, but results from this study highlight the need to prioritise reducing infants’ exposure to faecally contaminated soil while crawling around the household floors and mouthing their own hands, as those pathways posed the highest infection risks. However, it is apparent that discrete hygiene interventions targeting individual pathways will not be enough to reduce the enteric infection burden, as all the transmission pathways analysed posed a high risk of infection over time. This study reinforces the need for transformative changes to address the overall widespread high levels of faecal contamination in the infants’ living environment to reduce child stunting and achieve the Sustainable Development Goals.
