Clinicopathological Parameters and Sialyltransferase Activity in Trypanosoma Congolense-Infected Sheep

Abstract

Cleavage of erythrocyte surface sialic acid (SA) by the sialidase produced by trypanosomes is implicated in the pathogenesis of anaemia in African animal trypanosomiasis (AAT). Sialyltransferase (ST) mediates the attachment of SA to cell surface glycoproteins and glycolipids of desialylated erythrocytes. ST activities in Trypanosoma congolense-infected sheep and control groups were investigated and variations in their physio-biochemical properties were evaluated. Six (6) apparently healthy Nigerian Yankassa breed of sheep comprising of T. congolense-infected (n=3) and non-infected (n=3) groups were used for the experiment. Parasitaemia and packed cell volume (PCV) were determined daily over a 5-week period. Enzyme kinetics of partially purified ST from the thyroid gland were also evaluated. Anaemia (mean PCV= 18.83±0.71%) was observed in the T. congolense-infected sheep when compared with the non-infected control group (mean PCV 39.75±0.35%) and the observed differences were significant (p < 0.05) after five weeks post infection. Variations were also observed in the physio-biochemical properties (pH, temperature, activation energy) of the ST isolated from the T. congolense-infected and control sheep. This finding is believed to have been an induced response by the host to parasite’s activity and could be exploited further as a possible target in the control of AAT.