Assessment of Escherichia coli contamination risk across different environmental media in rural Ethiopia.

Escherichia coli (E. coli) pathotypes, particularly enteropathogenic and enterotoxigenic strains, are among the leading causes of moderate-to-severe diarrhea in low- and middle-income countries (LMICs). These pathogens are commonly transmitted through environmental media such as contaminated water, soil, and hands, often due to poor sanitation and hygiene. In this first phase of an ongoing longitudinal study, we conducted a cross-sectional assessment of E. coli contamination across multiple environmental compartments in 41 rural households in Daro Lebu Woreda, West Hararghe Zone, Eastern Ethiopia. Environmental samples were collected from drinking water, indoor and outdoor soil, and hand rinses of children under two and their mothers or caregivers to quantify E. coli levels and explore associations between contamination and household-level risk factors. From the data we collected, the source and risk factors for E. coli contamination are not readily apparent. These findings underscore the complexity of fecal contamination pathways in rural settings and highlight the need for integrated, multi-pathway interventions. Improving household hygiene behaviors, ensuring safe water storage, and upgrading sanitation infrastructure could significantly reduce exposure to enteric pathogens. Further large-scale and longitudinal studies are essential to better understand contamination dynamics and inform transformative WASH (Water, Sanitation, and Hygiene) interventions.