HAEMATOLOGICAL CHANGES IN SHEEP (Ovis aries) INFECTED WITH HUMAN INFECTIVE Trypanosoma brucei rhodesiense

The haematological parameters of sheep (Ovis aries) an experimental model of Human African Trypanosomiasis (HAT) were determined. Ten sheep were used; eight animals were infected with 1× 104 Trypanosoma brucei rhodesiense while two animals were not infected and hence used as control. Clinical evaluation was done daily while weekly animals of both groups were bled from the jugular vein and blood samples examined for  Packed Cell Volume (PCV), Haemoglobin (Hb), Red Blood Cell count (RBC), platelet counts, total white blood cell counts and erythrocyte indexes of Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Haemoglobin Concentration (MCHC). Clinical evaluation of the disease in the sheep corresponded closely to that described in human patients. Infected sheep showed an increase in body temperature, MCH and MCHC. However the levels of PCV, Hb, MCV and RBC counts declined drastically on infection. All parameters however recovered to control after treatment. Analysis of data revealed significant changes in all these parameters and erythrocyte indexes in infected sheep when compared with controls. From the changes observed in this study, we can conclude that microcytic anaemia was the major feature in the initial stages of the disease and while macrocytic anaemia was observed in the later stages of disease in the infected sheep.