Haematological and Blood biochemical changes in the pathophysiology of trypanoma congolese infection indigenous Zambian goats

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Witola, William Harold
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Trypanosomosis is an economically important parasitic disease of almost all domesticated animals in Zambia. However, very little work has been done to estabUsh the pathophysiology of the disease in animals in Zambia. The changes in haematological and blood biochemical parameters of infected animals are important in disease prognosis, treatment rationale and in determining the organs which have undergone pathological changes. Goats are important hvestock in tsetse-infested areas of Zambia probably due to their " exhibitance of partial trypanotolerance.The course of experimental Trypanosoma congolense (IL3000) infection in indigenous Zambian goats was followed during which the parasitaemia, clinical parameters, haematological parameters and serum proteins profiles were determined and erythrophagocytosis was investigated as a mechanism of anaemia. Parasitaemia was determined using the bufiy coat method, while the packed cell volume (PCV) was measured by the haematocrit method. The red blood cell (RBC) coimts, white blood cell (WBC) counts and haemoglobin (Hb) were determined using an electronic cell counter. The RBC indices were derived from the measured PCV, RBC counts and Hb. Erythrophagocytosis was investigated using radioisotope assays and microscopic methods. Serum total protein and albumin were determined by chemical methods (Biuret and Bromocresol green dye), the serum globiiUns concentration calculated by subtraction of globulin concentration from the serum total protein concentration and the A:G ratio determined.The strain of Trypanosoma congolense used was pathogenic, it produced disease in the goats characterised by rapid progressive anaemia, early phase leucopenia, high parasitaemia and classical clinical signs of trypanosomosis. Statistically significant (P < 0.05) mean reductions in values of PCV, haemoglobin and RBC counts were observed between the infected and the control goats starting from as early as 17 days post-infection and lasting up to 56 days post¬infection. Erythrocyte indices were stable throughout the infection period resisting in normocytic-normochromic anaemia. Significant (P < 0.05) evidence of erythrophagocytosis was observed using both radioisotopic and microscopic techniques. The mean serum total protein and globuUn levels increased significantly (P < 0.05) within 3 weeks of infection and remained elevated until the end of the experiment. It was evident the mean albumin levels did not show any significant (P > 0.05) variations while the A:G ratio significantly (P < 0.05) dropped in the fifth week and remained consistently low.This study showed that T. congolense infection in indigenous Zambian goats causes anaemia and that erythrophagocytosis is one of the mechanisms of this anaemia. Moreover, marked changes in serum protein profiles develop which are associated with the pathophysiology of the disease.
Tripanosomiasis -Zambia , Goats -Zambia