BEYOND DIARRHEA: FECAL-ORAL PATHOGEN TRANSMISSION AND ENVIRONMENTAL ENTEROPATHY IN IQUITOS, PERU
Exum, Natalie Giannelli
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The importance of clean water and adequate sanitation is a widely recognized characteristic of healthy communities. Across the developing world, many communities are without this vital infrastructure, thereby vulnerable to enteric infections from pathogens that travel through the environment and may cause diarrhea. Looking beyond diarrhea, a more serious, long-lasting subclinical condition called environmental enteropathy (EE) may develop in the intestinal tract from enteropathogen exposure, which permanently alters the ability of the intestine to take up nutrients and the host to fight off infections. The first manuscript of this dissertation relates water and sanitation conditions in households to child EE biomarkers in stool, urine and serum. This study found that the water and sanitation conditions were associated with fecal markers for EE in a peri-urban community of Iquitos, Peru. The results provide preliminary evidence for the hypothesis that children under 24 months of age living in unsanitary conditions will have elevated levels of fecal EE markers for gut inflammation and gut permeability that lead to stunting. The second manuscript characterizes fecal contamination on household floors, an important transmission route for fecal pathogens that may greatly affect children under 24 months of age who spend a lot of time playing and eating off the floor. This study found that households with improved sanitation and cement floors in the kitchen area had reduced fecal contamination compared to those with unimproved sanitation and dirt floors. These findings suggest that the sanitation facilities of a home may impact the microbial load found on floors, contributing to the potential for household floors to serve as an indirect route of fecal pathogen transmission to children. The third and fourth manuscripts present saliva as a novel and minimally invasive specimen for use in community based studies to assess microbial pressure and pathogen-specific infections. The outcome measure of salivary secretory immunoglobulin A was found to be associated with the sanitation and household characteristics of children living in peri-urban Iquitos, Peru and demonstrated an important proof of concept for future water and sanitation interventions that this marker can differentiate between households within a community.