Two-year impact of praziquantel treatment for Schistosoma japonicum infection in China: re-infection, subclinical disease and fibrosis marker measurements

We studied a community cohort of 193 individuals exposed to endemic Schisto soma japonicum infection in the Dongting Lake region of China to assess sub clinical morbidity and the 2-year benefit of curative therapy (praziquantel ) administered in 1996. Prevalence and intensity of S. japonicum infection before treatment were 28% and 192 eggs per gram faeces (epg), respectively. Two years after cure, 22% of the cohort were reinfected, but with a lighte r intensity (67 epg). Sixty-four subjects (37%) showed significant improvem ent in ultrasound parenchyma images after treatment and 51 subjects (54%) s howed significant improvement of periportal fibrosis. Left-lobe enlargement also reversed (P < 0.05) and splenomegaly reversed in 6 of 8 cases and dev eloped in only 1. Two years post-treatment a dilated portal vein became les s frequent, but the decline was not significant (16% vs 11%, P > 0.05). The serum levels of laminin and collagen IV associated with reinfection and in tensity and hyaluronic acid levels correlated with ultrasound findings (P < 0.01). Overall, treatment induced a marked decrease in subclinical hepatos plenic morbidity attributable to S. japonicum although low-intensity re-inf ection after treatment remained relatively frequent. Stratified analysis an d logistic models evaluated potential confounding factors for assessment of treatment effects on hepatic fibrosis. S. japonicum infection and moderate -heavy alcohol intake interacted: improvement in parenchymal morbidity was impeded among drinkers (P < 0.05). Chemotherapy focused on at-risk resident s controls prevalent subclinical hepatic fibrosis but re-infection indicate s the need for complementary control strategies.