Changes in the activity of the reticulo-endothelial system of rats during an infection with T. lewisi.

Data presented show that during the course of a Trypanosoma lewisi infection in rats there was both an activation of the phagocytic cells of the liver and spleen and an increase in their numbers. There was a marked lymphoid hyperplasia in the white pulp of the spleen with an increase in the number and size of the lymphoid follicles. Degenerative changes occurred in the liver parenchymal cells during the infection, and at certain stages large numgers of mononuclear cells were observed in the vascular sinusoids and other vessels of the liver.