 3.2. Study design The study design is based on the recent WHO guidelines on how to assess drug efficacy against STH. Briefly, following obtaining informed consent, school children in the target age range group will be recruited and asked to provide a recent stool sample an interval of less than 4 hours that will be processed to determine the fecal egg counts FEC for each STH present. For the initial sampling the aim is to enroll at least 650 children. This is based on a sample size of at least 50 infected subjects for each STH in each treatment arm cfr WHO guidelines, an apparent prevalence of 20 for the least prevalent STH species and a drop out of 20. 