UC Berkeley

Enteric pathogens are a leading cause of diarrheal illness in low-and middle-income countries and are transmitted through the fecal-oral route. Exposure routes can be blocked through adequate drinking water treatment, sanitation facilities and hygiene practices (WaSH). While these pathways are well understood conceptually, few studies have explored household transmission and the impacts of WaSH interventions with empirical measurements of enteric pathogens. In this dissertation, indicators and pathogens were measured in household reservoirs (stored drinking water, soil, and mothers and child hands) in rural Bangladesh to quantify the impact of a sanitation intervention on household level fecal contamination. Additionally, the reliability of indicator Escherichia coli to suggest risk of enteric pathogen infection was evaluated in this context. Fecal indicator organisms were also used to assess the importance of animal fecal sources in these households. Lastly, the association between bacterial communities in household reservoirs was quantified using 16S rRNA gene sequencing. Through this work I showed that the sanitation intervention in place had limited impact on household fecal contamination. In later chapters, indicator E. coli is shown to be a useful tool to indicate risk in this context as higher concentrations of indicator E. coli were associated with higher prevalence of pathogenic E. coli genes. I also determined that animals were potential sources of Giardia and pathogenic E. coli genes on mother hands. In Chapter 4, shared bacteria between mother and child hands, hands and soil, and mother hands and stored water suggest the potential for transmission of pathogens.