Schistosoma mansoni ‐related morbidity on Ukerewe Island, Tanzania: clinical, ultrasonographical and biochemical parameters

One thousand six hundred and ninety‐five inhabitants of 3 rural villages on Ukerewe Island, Lake Victoria, Tanzania, were examined by clinical, parasitological, ultrasonographic and—in part—serological means to evaluate Schistosoma (S.) mansoni‐related morbidity on a community level. Villagers frequently complained of typical colitis symptoms (abdominal pain 80.1%, bloody stools 43.1%, diarrhoea 35.1%); haematemesis, on the other hand, was rare (and reports doubtful in most cases). 16.9% of the population had been given praziquantel previously. Overall S. mansoni prevalence was 86.3%, with a median egg output of 176 eggs per gram (e.p.g.) and a maximum output of 17 984 e.p.g. Children and adolescents were infected more severely than adults, men more severely than women. Pretreated individuals excreted significantly fewer ova (median 124 vs 192e.p.g., P<0.001).