The influence of treatment on the development and course of murine hepato-splenic schistosomiasis mansoni

Previous studies have shown that mice treated at 5 weeks following infection with Schistosoma mansoni developed no disease, whereas their untreated counterparts rapidly developed hepato-splenic schistosomiasis. These findings were confirmed in the present study and, in addition, it was found that mice treated at 7.5 weeks when there were many eggs in the liver, and at 10 weeks when hepato-splenic schistosomiasis was fully developed, rapidly reverted to normal in regard to portal pressure and liver and spleen size. Having eliminated the source of eggs by killing the worms, it was possible to study the devolution of the egg lesions that were already present. The inflammatory cells rapidly disappeared, followed thereafter by a relatively sudden resorption of fibrous tissue. Between 25 and 52 weeks following treatment there was an almost complete disappearance of all egg lesions. Mice surviving treatment lived indefinitely, whereas all untreated animals died within 25 weeks following infection.