Anaemia in Yankassa Rams Infected with Trypanosoma Congolense, T. Vivax and T. Brucei and their Erythrocytic Responses

Abstract

One of the most consistent features of trypanosomiasis in any parasite host. The main objective of this study was to therefore evaluate the bone marrow responses to anaemia, generated in Yankassa rams infected with three most common trypanosomes species (T. congolense, T. vivax and T. brucei), affecting Nigerian animals, both at acute and chronic phases.Three groups of Yankassa rams were infected with Trypanosoma congolense, T. vivax and T. brucei, respectively. Each infection group was subdivided into two. While a subgroup was not treated to allow the animals run an acute course, the other subgroup precipitated a chronic course with the application of subcurative doses of diaminazene aceturate. In acute infections, there was a rapid development of anaemia, with PCV dropping down to between 16 and 17%, high parasitaemia in all the subgroups of the three infections, and death, especially in untreated T. brucei subgroup within 5 to 6 weeks of infection. The rapidly developed anaemia in acutely infected animals showed no evidence of increased erythropoiesis in circulation as measured by the level of reticulocytosis in all the three trypanosomal infections. Chronic infections ran for 8-15, 14-20 and 13-20 weeks post treatment in T. congolense, T. vivax and T. brucei infections, respectively. With subsequent relapses after treatment, infected animals had more severe anaemia with the PCV as low as 12 to 13% before death. Increased reticulocytosis developed between 7th and 9th weeks of infections coinciding with periods of low parasitaemia which was earliest with T. brucei infection. This however did not cancel the anaemia developed. Consequently, the reticulocyte responses throughout the infection were suboptimal and could not restore the declining PCV to normal, but at best, just maintained the low levels.

Keywords: Erythrocytic response, rams, Trypanosoma congolense acute course, reticulocytosis

Nigerian Journal of Parasitology, Vol. 32 [1] March 2011, pp.109-116