Clinicopathological and Microscopic Features of Trypanosoma brucei and Trypanosoma evansi Induced Infections in Sheep II

Abstract

The present study elucidates further on clinical, gross, and microscopic pathologies induced by single or mixed infections with Trypanosoma evansi and Trypanosoma brucei in sheep. Briefly, the experimental animals were divided into four groups of three animals each. Animals in each group were either infected with T. brucei, T. evansi, mixed (T. brucei and T. evansi), or noninfected. Animals were observed for clinical, gross, and microscopic pathologies for 98 days (14 weeks). The clinical pathologies observed included loss of body condition, pale ocular mucus membrane, rough hair coat, scrotal oedema, scrotal degeneration, emaciation, and death. At necropsy, macroscopic or gross lesions included very pale and anaemic carcass composition, congested and pneumonic lungs with severe haemorrhages, serous atrophy of intestinal and body fats, lymphadenopathy, splenomegaly, and hepatomegaly. Microscopic lesions observed in the testes, spleen, liver, lungs, lymphoid, heart, and brain tissues of infected sheep were varied and included swollen kidney with renal tubular degeneration, the proliferation of lymphocytes at the germinal centers of the spleen, degeneration of the bronchioles, severe testicular degeneration with a reduction in the number of spermatogenic cell layers, degenerated Leydig and Sertoli cells with loss of sperm reserves in the seminiferous lumen, congested liver with sinusoidal spaces and the proliferation of monocytes and lymphocytes. The results indicate that trypanosomosis due to experimental T. brucei, T. evansi, or mixed infections may be an important cause of various grades of tissue and organ pathologies in sheep in trypanosome-endemic areas.