Patency and Clinico-Haematological Pathologies Sequel to Trypanosoma brucei and Trypanosoma evansi Induced Infections in Yankasa Sheep I

Abstract

Trypanosomosis remains one of the most deadly protozoan diseases that pose a significant impact on livestock health in the tropics. Sixteen (16) rams aged between 24 to 30 months and weighed between 22-25kg were acclimatized under standard animal housing  conditions. Twelve (12) of the sheep deemed fit and healthy were randomly divided into four groups (I, II, III, and IV) of three sheep each. Each sheep in groups I and II was inoculated intravenously with 2 mL containing 2 X 10⁶ trypomastigote forms of Trypanosoma brucei and Trypanosoma evansi, respectively. While group III, each sheep received 2 mL containing 2 X 10⁶ mixed inoculums of T. brucei and T. evansi (50% each by volume of the infective inoculums). Sheep in group IV served as the non-infected control. Post-infection animals were monitored for 14 weeks for parasitaemia, clinical signs, and haematological pathologies. The patent infection became evident in groups I, II, and III between 5-21 days post-infection with average patency of 7, 20, and 8.5 days respectively. The infection was characterized by intermittent pyrexia with a significant decrease (p< 0.001) in mean weekly packed cell volume (PCV),  haemoglobin concentration (Hb), live weight gain, plasma protein, which significantly decreased (p< 0.001) in all the infected groups. Pearson’s correlation (r) indicates a strong positive correlation (r= 0.991) between parasitaemia and pyrexia, and principal component analysis (PCA) biplot increased the predictabilities of these two indices as the major precursors in the progression of the trypanosomes pathogenesis in sheep.

Keywords: Trypanosomosis; Patency; Clinico-haematological pathologies; Trypanosoma brucei; Trypanosoma evansi; Yankasa sheep