Evolution of Liver Fibrosis During Long-term Experimental Schistosoma japonicum Infection in Pigs

Sammanfattning: Schistosomiasis japonica, caused by the zoonotic trematode Schistosoma japonicum, is a highly debilitating parasitic disease endemic in China, the Philippines and Indonesia. The disease is a serious threat to public health and a major cause of liver fibrosis in humans. The tissue damage caused by the host tissue reaction to schistosome eggs trapped in the portal system of the liver leads to portal fibrosis and hypertension. The fibrosis is characterised by excessive deposition of extra-cellular matrix (ECM), especially collagen types 1 and 3 in various proportions, in portal areas. The pig is a natural host for S. japonicum and has several anatomical, physiological and immunological similarities with man, which has led to the exploration of the pig as a large animal model of human schistosomiasis japonica. In pigs, pronounced portal and septal fibrosis develops at the early stage of infection, when egg excretion is high and then gradually regresses over time as the pigs undergo self-cure. This makes the pig a useful animal model for studies of the pathogenesis of the development and resolution of liver fibrosis, including any qualitative changes in the ECM that may occur during the infection period.