Studies on Comparative Hematological and Biochemical Changes in Yankasa Sheep Experimentally Infected with Trypanosoma vivax and Trypanosoma congolense Field Isolates of Nigerian Origin

Abstract

Background: African Animal Trypanosomosis is one of the key hindrances to full livestock development in most parts of sub-Saharan Africa, despite years of efforts to eradicate the disease. It is an important parasitic disease of human and animals. Control of the disease relies majorly on chemotherapy of one of the three trypanocidal drugs. The severity of haematological indices depends on parasite species, host involved and nutrition. Hence, there is need to assess the pathogenicity and compare their effects on some of our local breeds of livestock. Methodology: Field isolates Trypanosoma vivax and Trypanosoma congolense of Nigerian origin were used. Thirty sheep were acquired and preconditioned for two weeks in arthropod- proofed pens before the commencement of the experiment. The sheep were divided into five groups (A- T. vivax infected-treated, B- T. vivax infected-untreated, C- No infection, no treatment, E- T. congolense infected-treated and F- T. congolense infected-untreated. Packed Cell Volume, serum protein, WBC, DLC were monitored weekly for 8 weeks. Results: There was gradual decreased in PCV of all the infected animals which was an indication of anaemia but more severe in T. vivax groups. Also decreased in plasma protein that was more pronounced and prolonged in T. vivax than the T. congolense groups, this was similar with WBC. Neutrophils had initial increased in all the groups before dropping and low value of monocyte at the early period of infections which later disappeared. There was no basophil seen in all the T.vivax groups but few were observed in T. congolense groups.   Conclusion: Anaemia is a general feature of most parasitic infections especially in trypanosomosis. Trypanosoma vivax used in this study is more pathogenic than the T. congolense, hence may have more negative effects in sheep production in author’s environment.