The pathology and pathogenesis of Trypanosoma vivax infection in the goat.

Acute and chronic forms of disease can be distinguished in Trypanosoma vivax infection in the goat. The main difference between the acute and chronic form seems to be the presence of microthrombi in the acute stage of infection; these consist of platelets, trypanosomes, monocytoid cells and some fibrin. This thrombus formation seems directly related to the high parasitaemia in acute trypanosomiasis and may result in ischaemia which could also explain the haemorrhages, the oedema of the lungs and other tissues, and the necrotic changes found in several organs. The anaemia, associated with erythrophagocytosis, haemosiderosis, extramedullary haemopoiesis and hyperactivity of the bone marrow, seemed to be of haemolytic origin. The factors leading to emaciation seemed to be degenerative atrophy of muscular tissue and loss of protein in the urine caused by a possible immune complex glomerulonephritis.