Schistosomosis are parasitic diseases caused by blood flukes of the Schistosoma genus. The pathology of schistosomosis is mostly brought about by ova trapped in the tissues. In the liver, granuloma around ova eventually trigger periportal fibrosis and portal hypertension. In S. mansoni infection, the infection intensity and the onset of liver fibrosis are under distinct genetic control. Liver fibrosis is the main cause of death in the 20 millions individuals suffering from chronic schistosomosis. However, liver fibrosis is reversible if antischistosomal drugs are administered before the onset of severe hepatic insufficiency.