An Open Label Dose Finding Safety and Efficacy in Children and Infants Infected With Schistosomiasis (S.Mansoni)

Inclusion Criteria: * Male and female children aged 2 to 6 years (Part 1) and 3 to 24 months (Part 2) * S. mansoni positive diagnosis defined as positive egg counts in stool (greater than \[\>\]1 egg/1 occasion) according to World Health Organization (WHO) classification : light (1-99 eggs per gram of faeces), moderate (100-399 eggs per gram of faeces) and heavy (greater than or equal to \[\>=\]400 eggs per gram of faeces) infections * Minimum weight of 8.0 kg in 2- to 6-year-old children and of 4.0 kg in 3- to 24-month infants • Parents/legal representative ability to communicate well with the Investigator, to understand the protocol requirements and restrictions, and willing their children to comply with the requirements of the entire trial, i.e. * To be examined by a study physician at screening and 14-21 days after treatment * To provide stool and urine samples at screening, 24 hours and 8 days after treatment, as well as 14-21 days after treatment * To provide finger prick blood samples for Pharmacokinetics (PK) studies and blood samples for safety assessments Exclusion Criteria: * Treatment in the 4 weeks prior to study screening with Praziquantel (PZQ) , other anti-helminthic, antimalarial or anti-retroviral compounds or any other medication that might affect the PK of PZQ such as certain antiepileptics (e.g., carbamazepine or phenytoin), glucocorticosteroids (e.g., dexamethasone), chloroquine, rifampicin or cimetidine * For children being breast fed, treatment of the mothers/wet nurses with PZQ in the 3 days prior to administration of Investigational medicinal product * Previous history of adverse reactions associated with PZQ treatment * Marked increases of the liver transaminases (alanine aminotransferase and/or aspartate aminotransferase) above 3x Upper Limit of Normal (ULN) * History of acute or severe chronic disease including hepato-splenic schistosomiasis * Fever defined as temperature above 38.0 degree centigrade * Debilitating illnesses such as tuberculosis, malnutrition, etc. as well as a medical history of seizures * Mixed S. haematobium and S. mansoni infections * Findings in the clinical examination of schistosome-infected children participating in the study as performed by the study clinician on the treatment day, that in the opinion of the Investigator constitutes a risk or a contraindication for the participation of the subject in the study or that could interfere with the study objectives, conduct or evaluation * Unlikelihood to comply with the protocol requirements, instructions and trial-related restrictions, e.g., uncooperative attitude, inability to return for follow-up visits, and improbability of completing the trial