Acute Babesia bigemina infection: changes in coagulation and kallikrein parameters.

Plasma from splenectomized calves infected with B. bigemina were assayed for disturbances in the coagulation system. Changes were observed in the WBCT, PTT, PT, TT and RT as well as in fibrinogen, calcium and thrombocyte levels. These changes were most marked during days 6--7 when parasite numbers were greatest. Massive intramuscular haemolysis coincided with these changes. The plasma kallikrein level fell progressively from days 6--11 and the level of activated kallikrein rose slightly. Parasite doubling time was calculated at 8.13 h. The similarities and differences between this disease and B. argentina infections of cattle are discussed.