All patients from the study area presenting for care at the hospital with diarrhea will be included in routine hospital surveillance.The diarrheal disease surveillance for the project will be conducted at icddr,b hospitals at Mohakhali and Mirpur and other health facilities for patients coming from the Mirpur study area (wards 7-13 , 15 and 41). Clinical staff at each of the two hospitals and other facilities will evaluate each patient at the hospital triage area and provide treatment as per the routine procedure.