Environmental enteric dysfunction (EED) affects 50-90% of children in low-income countries and is likely an important factor in child stunting as it impedes efficient nutrient uptake in the small intestine. EED is suspected to be the result of persistent exposure to enteric pathogens, although it has not been correlated with any specific pathogen. My work will identify if the reduction of exposure to enteropathogens in a child’s household environment through low-cost water, sanitation and hygiene (WASH) interventions can prevent and/or ameliorate EED. I will explore the impact of pathogen load on the gastrointestinal ecosystem, including microbial and host factors (e.g. intestinal inflammation), and elucidate changes in flux through key microbial metabolic pathways associated with higher pathogen load. I will further explore how long-term nutritional supplementation from age 6-24 months can positively shape the ecosystem by providing a source of microbial derived dietary metabolites that are beneficial in reducing intestinal inflammation.