Abnormality of osmotic fragility and morphological disorder of bovine erythrocytes infected with Theileria sergenti.

Abstract

The osmotic fragility and the surface structure of erythrocytes obtained from 3 calves infected with Theileria sergenti and from 3 phlebotomized ones were compared. As the parasitemia progressed, the osmotic fragility of the erythrocytes significantly increased in the infected calves. Particularly the hemolysis ratio in the isotonic area (21.5-94.1%) obviously increased. On the other hand, the percentage of parasitized cells in the erythrocytes did not show so much high values (16.1-21.3%). Similar phenomenon was found in each different percentage of erythrocytes suspension which was separated from density gradient centrifugation. No significant difference in the serum osmotic pressure between the infected calves and the phlebotomized calves was found. By scanning microscopy, the erythrocytes of infected calves, which were collected at the crisis period of parasitemia, were almost completely deformed and showed echinocyte form. Moreover, the appearance ratio of echinocyte form in the erythrocytes population was superior to the percentage of parasitized erythrocytes. Similar membranous alterations were also observed in the erythrocytes of grazing cattle in the crisis period of the theileriosis. It was proven that abnormality of osmotic fragility and morphological disorders of erythrocytes occurred not only in parasitized erythrocytes but also in non-parasitized ones in T. sergenti parasitemia.