Margaret Kosek of Johns Hopkins University in the U.S. and co-investigators will generate a new biomarker panel to assess disease activity in environmental enteropathy, which causes stunted growth and malnutrition. They will analyze markers related to immune system activation and growth factors in samples derived from the children enrolled in the MAL-ED (malnutrition and enteric diseases) study in Peru, and compare them with growth profiles and diarrheal disease burden as a proxy for disease activity.