International Journal of Enhanced Research in Medicines & Dental Care, ISSN: 2349-1590 Vol. 1 Issue 8, October-2014, pp: (7-11), Available online at: www.erpublications.com Page | 7 Cytological Indices of Peripheral Blood and Bone Marrow Smears in Albino Rats infected with Trypanosoma Brucei Brucei Bolaji David AKINBO 1 , Adedeji David ATERE 2 , Oladele Olatubosun ELUWOLE 3 1,3 Haematology Unit, Department of Medical Laboratory Science, Achievers University, Owo, Nigeria 2 Chemical pathology Unit, Department of Medical Laboratory Science, Achievers University, Owo, Nigeria Abstract: Trypanosomiasis is a debilitating disease in man and animals which has adversely affected economic and social well-being of sub-Saharan Africans. Haematological parameters were determined in fifty (50) male albino rats, in which thirty five (35) were infected with Typanosoma brucei brucei and the effects of this condition was assessed on peripheral blood and bone marrow cells using cytochemical stains. Data obtained were statistically compared and P˂0.05 was considered significant. Rats in infected group had significantly lower HCT, RBC, HGB and MCV levels and significantly higher WBC, MCHC, lymphocytes and mixed cells levels compared with controls. Cytochemical reactions of bone marrow cells revealed that all granulocytes, except myelocytes and basophils, were peroxidase positive. It could be concluded in this study that the infected rat subjects suffered severe haemolytic anaemia and leucocytosis observed in the infected group attributed to the immune response to trypanosome infection. Keywords: Hematological Indices, Trypanosoma brucei brucei, bone marrow, Albino rats. Introduction Trypanosomiasis is a complex and debilitating disease in man and animals which has adversely affected economic and social well-being of sub-Saharan Africans (1, 2). The Human African Trapanosomiasis (HAT) is caused by two subspecies of the protozoan parasite and it is a parasitic disease transmitted by tsetse fly (Glossina Genus) (1, 3). Trypanosomiasis which is also known as sleeping sickness and nagana in man and animals respectively is caused by African trypanosomes (4, 5, 6). The trypanosome species affecting man and his domestic animals have been subdivided into two groups, the haematinic group (Trypanosoma congolense, T. vivax) which remains in the plasma and the tissue invading group (T. brucei, T. evansi, T. gambiense, T. rhodesiense and T. equiperdum) found in extra and intra vascular spaces (7, 4, 3). The invading effects of these parasites in the blood produce numerous changes in the cellular and biochemical constituents of blood (8, 9). Trypanosoma brucei infection precipitate increased red blood cell destruction which results in anaemia as well as tissue damage like other trypanosome infections (10, 11). These changes together with the need by the host to destroy the parasite are presumably responsible for the symptoms of African sleeping sickness. Haemolymphatic phase in humans, the first stage of the disease, is characterised by clinical features like fever, headaches, joint pains, lethargy and itching. The neurological phase, the second stage, begins when the parasite crosses the blood-brain barrier and invades the central nervous system resulting in clinical features like confusion, sensory disturbances and poor coordination. This is a very crucial stage of this phase because the sleep cycle would be disturbed and this gives the disease its name. (1, 3). In years back, several other studies have been carried out on the haematology of trypanosomiassis and intermittent episodes of pancytopaenia and sometimes, isolated anaemia, neutropaenia and thrombocytopaenia had been reported in Trypanosome-infected animals (12, 13, 3). But there is paucity of information of the effect of trypanosomes on the haemopoietic activity of the bone marrow and the characteristics of the more primitive cells. The ability of the erythropoietic system to continue to produce normal cells from the stem cell precursors in the presence of infection is quite remarkable (14, 3). Anaemia had been reported to be a critical feature in the pathogenesis of African trypanosomosis (14). Considering a rapid decline in haemamogram and pallor in mucous membranes in the infected hosts, a defect in the bone