Chronic hepatitis in experimental schistosomiasis.

Histological features of chronic active and chronic persistent hepatitis were observed in mice, rabbits and non-human primates infected with either Schistosoma mansoni and Schistosoma japonicum. In early infection hepatitis appeared as a reactive change due to liver damage caused by the deposition of schistosome eggs, but portal and septal cellular infiltrations tended to remain long after parasite aggression had diminished or disappeared, either spontaneously with time or after chemotherapy. In rabbits, and to a lesser degree in monkeys, a picture of chronic active hepatitis was present, with evolution to cirrhosis in the former. The experimental findings indicate that schistosomiasis has the potential to induce chronic hepatitis and suggest that the current assumption that chronic hepatitis seen in humans with schistosomiasis is always due to concomitant viral infection should be reviewed.