The overall objective of the project is to contribute to an increased knowledge about the effect of praziquantel on schistosomiasis related morbidity and re-infection level among communities living along Lake Victoria in Mayuge district, Uganda with the overall aim of improving the strategies for morbidity control.

The study will be carried out in a high transmission area along Lake Victoria, in Mayuge district. It will be a randomised intervention study, comparing a single praziquantel treatment (40mg/kg) with two standard doses administered two weeks apart.

In Uganda, schistosomiasis affects approximately 10% of the population and transmission takes place along all large water bodies (rivers and lakes).

Morbidity control should aim at increasing the length of time before morbidity reappears and decrease the time during which morbidity regresses in a situation with continued transmission and re-infection. It is proposed to test this by comparing the standard treatment with a double treatment (2 x 40 mg/kg) two weeks apart.

The overall objective of the project is to contribute to an increased knowledge about the effect of praziquantel on schistosomiasis related morbidity and re-infection level among communities living along Lake Victoria in Mayuge district, Uganda with the overall aim of improving the strategies for morbidity control.

The study will be carried out in a high transmission area along Lake Victoria, in Mayuge district. It will be a randomised intervention study, comparing a single praziquantel treatment (40mg/kg) with two standard doses administered two weeks apart. Two groups of participants, with 270 people in each, will be randomly selected and randomly assigned to the two treatment regimens. Three consecutive stool samples will be from the cohort and blood samples for malaria will be examined. Clinical and ultrasonographic examinations will be performed. After all the examinations, the whole cohort will be treated with a single standard dose of praziquantel and albendazole. Two weeks later all members of one of the groups will receive another standard dose of praziquantel. Follow-up examinations will be performed 8 weeks, 6 months and two years later.

Inclusion Criteria:

• age > 7 years Residence in project village

Exclusion Criteria:

• persons treated with praziquantel within 2 weeks before recruitment