The pathogenesis of Trypanosoma congolense infection in calves. IV. The kinetics of blood coagulation.

Blood coagulation studies showed there was a pronounced thrombocytopenia and hypofibrinogenemia in Holstein calves infected with Trypanosoma congolense TREU 112. There was also ineffective thrombopoiesis characterized by an increased megakaryocytic mass, reduced uptake of 35S-methionine into peripheral blood platelets and a normal platelet lifespan. There was an increased uptake of isotopic label into fibrinogen and a shortened half life indicating a consumptive error with increased peripheral use of fibrinogen. No consistent abnormalities were found in ethanol gelation, partial thromboplastin time, clot retraction and lysis or plasminogen assay. Fibrin split products were rarely detected. These findings suggest that in the chronic form of bovine trypanosomiasis there is a partially compensated consumption coagulopathy.