In vivo microscopy of schistosomiasis. II. Migration of Schistosoma mansoni in the lungs, liver, and intestine
Bloch, E.H.
American Journal of Tropical Medicine and Hygiene 29(1): 62-70
1980
ISSN/ISBN: 0002-9637 PMID: 7352629 Document Number: 158381
In vivo microscopy was used to examine the migration of schistosomules and eggs of Schistosoma mansoni in mice. Migration of schistosomules in the organs was restricted to the vascular system. The youngest schistosomules migrated passively but the migration of those with pigment in their caeca was active. In the liver such schistosomules were found only in the branches of the portal system. During feeding the worms faced the direction of blood flow. In the liver they interfered with the blood flow in these vessels and in adjacent sinusoids causing dilation and sarculation of the sinusoids and inflammatory changes and ultimately stasis, which led to necrosis of the liver cells and invasion by macrophages. In the wall of the intestine, ova were always found in vessels of diameter greater than 60 mu m. When single ova were present in small vessels the vessel sacculated at this site and the egg passed through the vessel wall. Clusters of ova blocked the blood flow causing necrosis of the vessel wall and liberation of the ova into the parenchyma. The eggs were at first parallel to the wall of the intestine, and they were found in all layers of the intestine except the villi.