A Study to Characterize the Clinical Presentation and Course of Cryptosporidium in Pediatric Participants

Inclusion criteria: * Age 6 months to 59 months with diarrhea according to the World Health Organization (WHO) criteria (≥3 loose stools daily for at least 2 days) * QuikChek™ and Stool microscopy positive for Cryptosporidium at screening * Acute (\<7 days), prolonged (lasting 7-13 days), persistent (lasting 14-28 days) or chronic (lasting \>28 days) diarrheal illness (≥3 loose stools daily, as defined by WHO) at screening * Normal nutritional status, mildly-to-moderately acutely malnourished, or severely acutely malnourished according to WHO definitions (number of participants with severe acute malnutrition will be capped) at screening * Parent or primary caregiver is willing to provide informed consent and to comply with study procedures, including provision of whole stool samples at the scheduled time points and willing to be followed up to 21 days Exclusion criteria: * Bloody diarrhea, defined as diarrhea with visible blood in stool as observed by the study team member performing the screening or reported by parent/primary caregiver * Other morbidity requiring emergency medical care in an intensive care setting at the time of screening * Coincident non-enteric infection including upper or lower respiratory infection at screening * Any participant whose parent or primary caregiver is unwilling or unable to cooperate with study procedures, in the investigator's opinion * If the parent/primary caregiver managing care of the patient has travel plans out of the study area t…