Ultrastructural changes in Babesia argentina infected erythrocytes in kidney capillaries

In a previous report it has shown that B. argentina infected erythrocytes in both kidney and venous blood appeared to be normal, unlike infected erythrocytes in brain capillaries which had a stellate appearance. The majority of infected erythrocytes in the brain were hemolyzed and closely packed together, sticking to one another and to the capillary endothelium. Parasitized red cells in kidney capillaries were not closely packed together, and generally did not appear to be sticking either to one another, or to the capillary endothelium. The capillary endothelium appeared undamaged. Infected red cells had a homogeneous, osmiophilic cytoplasm, but their margin was grossly distorted, being twisted into bizarre shapes. The margin of the infected erythrocyte was also characterized by small strands radiating from it, similar to those seen in infected red cells in brain capillaries. Uninfected red cells had a normal biconcave appearance. Two and sometimes four parasites appeared to be present in infected red cells. These parasites always appeared normal. It is suggested that different strains of B. argentina induce different effects on the red cells. The reason is not known, but proteolytic enzymes might cause weakening of the stroma and distortion of erythrocytes. These enzymes, if present, could be found in different amounts in different strains