After obtaining informed consent from children's caregiver, the medical history of the participating individuals will be assessed with a standardized questionnaire, in addition to a clinical examination carried out by the study physician on the treatment day. Enrollment will be based on two stool samples which will be collected, if possible, on two consecutive days or otherwise within a maximum of 5 days apart. All stool samples will be examined with duplicated Kato-Katz thick smears by experienced laboratory technicians.