Characterization of the murine model of schistosomal hepatic periportal fibrosis ('pipestem' fibrosis).

During mild (one to two pairs of worms) and prolonged (23 weeks or more) mouse infections with Schistosoma mansoni, but not with S. japonicum, periovular granulomas and fibrosis were seen to be preferentially located along periportal tissues. This caused fibrotic expansion of the portal spaces on a background of normal-looking hepatic parenchyma, a picture mimicking 'clay pipestem fibrosis' seen in human patients with advanced schistosomiasis. The model was reproduced in outbred and in several strains of inbred mice, and their main characteristics were studied and compared to the human counterpart. A balanced consideration of the similarities and differences between the murine model and human pipestem fibrosis is needed for the adequate utilization of this simple, reproducible and inexpensive experimental model.