Ultrasonographic assessment of the regression of bladder and renal lesions due to Schistosoma haematobium after treatment with praziquantel.

The effect of praziquantel on urinary tract lesions due to Schistosoma haematobium was assessed by ultrasound in an endemic village in Niger. Ten months after treatment with praziquantel, bladder and renal lesions among the 149 patients were assessed. The parasitological cure rate was 87%. Ultrasonography proved to be an excellent tool to assess pathological changes. It is reliable, quickly performed, well accepted by the community and permits the definition of a "regression-rate" of the pathological lesions. Ten months after treatment, the "regression-rate" of bladder lesions was 68% and of renal lesions was 73%. The presence of bladder lesions had a negative influence on the regression of renal lesions. Nearly all renal lesions, without bladder lesions, regressed within the ten months period of observation. This study permitted the identification of a group of persons whose bladder lesions did not regress and who were possibly more vulnerable to the development of bladder cancer, thus requiring long-term follow-up.