A. Singh et al., Studies on some blood parameters of crossbred calves with experimental Theileria annulata infections, VET RES COM, 25(4), 2001, pp. 289-300
Subcutaneous inoculation of 1 ml of ground Theileria annulata tick tissue s
tabilate (0.75 tick equivalent) into crossbred calves (n = 6, average age 5
3 days) resulted in the development of acute theileriosis. The percentage p
arasitaemia was 71.7%+/-3.3% on day 20 after inoculation. Macroschizonts we
re observed in lymphocytes and monocytes. Phagocytosed schizonts were obser
ved in neutrophils, along with cytoplasmic vacuolation in monocytes and neu
trophils. There was progressive decrease (p <0.05) in the haemoglobin and p
acked cell volume, along with a marked reticulocytosis. Serum analysis reve
aled a decrease (p <0.05) in the concentrations of calcium, cholesterol and
triglycerides, while there was an increase (p <0.05) in the concentrations
of blood urea nitrogen as compared to day 0 values. The total serum protei
ns, albumin and serum immunoglobulin concentrations and the albumin-to-immu
noglobulin ratio showed marked decreases (p <0.05). Coagulopathies included
thrombocytopenia and an increased prothrombin time, along with a non-signi
ficant increase in the bleeding time and activated partial thromboplastin t
ime during the terminal stages of the disease. There was an increase in the
osmotic fragility of erythrocytes during the disease. Morphological altera
tions in the erythrocytes were observed with the developing parasitaemia.