Histopathology of Trypanosomiasis in Naturally Infected Cattle in Lafia, Nasarawa State, North Central Nigeria

Animal trypanosomiasis caused by Trypanosoma species transmitted by tsetse flies continues to threaten cattle production in tsetse-infested areas of Nigeria's North Central zone. This study characterised the gross and histopathological lesions of trypanosomiasis in naturally infected cattle in Lafia, Nasarawa State, between March and August 2023. Forty-two cattle with clinical signs of weight loss, anaemia, and progressive weakness confirmed positive by the buffy coat technique for Trypanosoma vivax or Trypanosoma congolense infection were selected. Blood samples were examined microscopically for parasites, and haematological parameters were determined. Tissue samples from the spleen, lymph nodes, liver, heart, brain, and kidney were collected at necropsy and processed for histopathological evaluation. Gross lesions included generalised lymphadenopathy, splenomegaly, anaemia-associated pallor, cardiac dilatation, and watery blood. Microscopically, reactive lymphoid hyperplasia was prominent in lymph nodes and spleen. Hepatic changes included periportal mononuclear infiltration and Kupffer cell hyperplasia. Myocardial lesions consisted of focal cardiomyocyte degeneration with lymphoplasmacytic myocarditis. Renal glomerulonephritis with mesangial hypercellularity was noted in 40.5 percent of cases. These lesions are consistent with current African trypanosomiasis pathology literature. The study recommends integrated tsetse control, expanded use of trypanotolerant breeds, and improved diagnostic capacity in Nasarawa State. Keywords: trypanosomiasis, cattle, histopathology, Nasarawa, tsetse