Animal Feces Contribute to Domestic Fecal Contamination: Evidence from <i>E. coli</i> Measured in Water, Hands, Food, Flies, and Soil in Bangladesh

TLDR

Fecal‑oral pathogens spread through complex environmental pathways, and isolating human feces has limited effect on contamination. The study aimed to quantify domestic fecal contamination in high‑coverage sanitation settings, assess animal contributions, and evaluate inter‑pathway effects. Researchers sampled water, hand rinses, food, soil, and flies from 608 households and quantified E. coli using IDEXX Quantitray MPN assays.

Abstract

Fecal-oral pathogens are transmitted through complex, environmentally mediated pathways. Sanitation interventions that isolate human feces from the environment may reduce transmission but have shown limited impact on environmental contamination. We conducted a study in rural Bangladesh to (1) quantify domestic fecal contamination in settings with high on-site sanitation coverage; (2) determine how domestic animals affect fecal contamination; and (3) assess how each environmental pathway affects others. We collected water, hand rinse, food, soil, and fly samples from 608 households. We analyzed samples with IDEXX Quantitray for the most probable number (MPN) of E. coli. We detected E. coli in source water (25%), stored water (77%), child hands (43%), food (58%), flies (50%), ponds (97%), and soil (95%). Soil had >120 000 mean MPN E. coli per gram. In compounds with vs without animals, E. coli was higher by 0.54 log