Schistosomiasis mansoni and viral B hepatitis in woodchucks

Background/Aims: An interaction between human schistosomiasis and viral hep atitis B has often been suggested, but never established. The experimental investigation has been hampered by the lack of a suitable model. Only woodc hucks are susceptible to both Schistosoma mansomi and a B-like hepatitis vi rus (WHV) infections. This study explores the relevance of this unique mode l regarding hepatitis/schistosomiasis interactions. Methods: Woodchucks (Marmota monax and Marmota marmota) were infected with: (a) S. mansoni; (b), WHV; or (c), both S. mansoni and WHV. Results: Following the experimental parasitic infection of woodchucks, with or without WHV, schistosomiasis presented a peculiar and severe course in early infection, involving mostly the intestines. Subsequently, the intesti nal and hepatic lesions underwent considerable modulation and the periovula r granulomas decreased in size and number, while the parasitic infection te nded to self-cure within the 9 months following infection. Nine woodchucks inoculated with the hepatitis virus alone presented with several degrees of acute and chronic hepatitis, with one of them dying of hepatocarcinoma 1 y ear after inoculation. Four woodchucks with concomitant viral and schistoso me infections presented with a simple additive pattern of lesions, without any evidence of modification or aggravation of either one of the two infect ions. Similarly, no significant impact of schistosomiasis on WHV serum mark ers could be seen. Conclusions: Schistosomiasis and viral hepatitis in woodchucks run parallel courses, with neither apparent special histological features derived from the association of the two conditions, nor modulation of WHV replication, S chistosomiasis itself, however, was observed to run a peculiar course in th e woodchuck. The present data are important for consideration in further ex periments exploring the interplay between schistosomiasis and viral hepatit is induced liver damage in this unique experimental host. (C) 2001 European Association for the Study of the Liver. Published by Else vier Science B.V. All rights reserved.