Effects of repeated praziquantel treatment on schistosomiasis mekongi morbidity as detected by ultrasonography.

Schistosomiasis mekongi is endemic in the Mekong River basin; about 80,000 people are at risk of infection in Cambodia. We conducted ultrasonographic studies of patients with schistosomiasis mekongi in Kratie province, Cambodia, focusing especially on the relationship between the frequency of praziquantel treatment and findings of ultrasonographic imaging. The frequency of praziquantel treatment in the period from 1995 to 2002 was classified into four groups: 1-2, 3-4, 5-6, and 7-8 times. Ultrasonographic images were examined to determine the presence of thickening of the portal vein wall and formation of meandering collateral circulation of the splenic vein. We selected these parameters because they are unaffected by interobserver bias. The results showed that thickening of the portal vein wall may have potential to improve with frequent praziquantel treatment. On the other hand, established hard splenomegaly and meandering collateral circulation of the splenic vein, improved very little with praziquantel treatment.