Association of the therapeutic activity of praziquantel with the reversal of Symmers' fibrosis induced by Schistosoma mansoni.

The impact of antischistosomal chemotherapy on the most important complication of intestinal schistosomiasis, Symmers' periportal fibrosis, has not been determined. Since abdominal ultrasonography has proven to be an effective tool in assessing the extent of Symmers' fibrosis in patients, we monitored the effect of chemotherapy, which involved the annual administration of praziquantel, on 48 Sudanese villagers having varying degrees of Symmers' fibrosis. Results indicate no significant differences in the fibrotic status of the 48 patients between 1986 and 1987, but test statistics (both the Wilcoxon signed rank test and Friedman's block/treatment test), indicated a significant decrease between the fibrotic status of the patients in 1986 and their fibrotic status in 1988 and 1989. Thus, after three years of therapy, 12 of the 48 patients no longer had detectable Symmers' fibrosis, while another 16 patients experienced a reduction in the amount of fibrosis in their livers. When coupled with our previous study, which demonstrated that annual treatment of children with praziquantel prevents the appearance of Symmers' fibrosis, it now appears that praziquantel may reverse this schistosomal-induced pathology.