Tissue responses in experimental schistosomiasis japonica in the pig: a histopathologic study of different stages of single low- or high-dose infections.

Abstract

Abstract. The tissue responses of pigs exposed to either 100 or 2,000 Schistosoma japonicum cercariae were examined at 4, 11, 17, and 24 weeks postinfection (PI) to explore the pig as an animal model for pathologic aspects of human schistosomiasis japonica. Egg granulomas were present in the liver, intestine, and occasionally in the lungs from 11 weeks PI. There were also many free eggs and early exudative reactions to eggs in the intestine. At 11 weeks PI, pigs in the higher dose group showed marked periportal and septal fibrosis with minimal parenchymal destruction. Thereafter, lesions regressed spontaneously as the pigs underwent a self-cure. The lower dose group showed only mild lesions throughout the study. The degree of hepatic fibrosis was correlated with the density of eggs and granulomas in liver tissue. The results indicate that the pig would be particularly useful for studies of the development and resolution of schistosomal hepatic fibrosis, and also for investigations of the mechanisms behind the self-cure phenomenon.

A complex of the blood fluke genus Psettarium (Digenea: Aporocotylidae) infecting tetraodontiform fishes of east Queensland waters

“…Eggs in the mesenteric tissues and vessels formed cysts similar to those reported by Bray et al [7] for P. nolani. These cysts were formed in association with multiple eggs and, on one occasion, degenerate worms, appearing consistent with venal thickening and phlebitic reaction, as described by Wood & Bacha [14] and Hurst et al [42] for schistosomatid infections.…”

Effect of anluohuaxian tablet combined with γ-IFN on schistosomal liver fibrosis

“…Blockage caused by accumulation of schistosomal egg in portal area, the microcirculation disturbance as well as the relative immune responses afterwards were the important pathological basis in the development of hepatic fibrosis. Our research also showed that there was also certain correlation between the size of schistosomal egg granuloma and liver fibrosis, which was consistent with some resent researches [14,15] . After treated with anluohuaxian tablet combined with γ-IFN, the collagen area and the size of egg nodules were reduced.…”

“…Our study demonstrated that hepatic pigments were distributed mainly in the connective tissue of catchment area, hepatic sinus, HSC, and Kuffer cells or around egg nodules, which could be seen in HE-staining and DAB staining. There was certain correlation between accumulation amount of pigments and the degree of liver fibrosis, which was consistent with the study by some researchers [14,15] . The formation of schistosomal egg granuloma was considered to be mediated by T cells.…”

Malnutrition and hepatic fibrosis in murine schistosomiasis

“…Concerning Symmers' fibrosis (clay pipestem fibrosis), different experimental hosts have been tried (Cheever et al 2003), such as monkeys (Lichtemberg & Sadun 1968, Sadun et al 1970, Lichtemberg et al 1971, Damian et al 1976, Farah et al 2000, rabbits , pigs (Hurst et al 2000), and mice (Warren & DeWitt 1958, Andrade & Warren 1964, Cheever 1965, Warren 1968, Andrade 1987a, Andrade & Cheever 1993. In this last animal model, during mild (one to two pairs of worms) and prolonged (16 weeks or more) infections with Schistosoma mansoni, a picture mimicking "clay pipestem" fibrosis seen in humans with advanced schistosomiasis has been reproduced in outbred and in some strains of well-nourished inbred mice (Andrade & Cheever 1993), but not in undernourished outbred specimens (Coutinho et al 1997).…”