Effect of Concurrent Trypanosoma brucei Infection on Haemonchosis in Red Sokoto (Maradi) Goats

Abstract

The effect of concurrent Trypanosoma bruceiinfection on caprine haemonchosis was investigated in Red Sokoto (Maradi) goats infected with either Haemonchus contortus alone or concurrently with Trypanosoma brucei. The goats infected with H. contortus alone manifested clinical disease that was mild and without mortality. On the other hand, concurrent infection with T.brucei resulted in severe clinical disease characterized by pyrexia, pallor of visible mucous membranes, anorexia, loss of body weight, diarrhoea and death of all the animals 18 - 24 days post infection. The concurrent infection with T. brucei also resulted in shorter prepatent period (16 ± 0.5 days) and the establishment of a greater number (137 ± 24) of adult Haemonchus worms per animal than in those infected with only H. contortus alone with prepatent period of 18 ± 0 days and 98 ± 26 adult worms per animal. Reduction in the packed cell volume, increased erythrocyte sedimentation rate, persistent monocytosis and leucopenia characterised by lymphopenia and neutropenia were associated with the concurrent infection while Haemonchus infection alone resulted in persistent eosinophilia. The results of the study show that a concurrent trypanosome infection may potentiate the
clinical severity of an otherwise sub-clinical infection with H. contortus in Red Sokoto goats through reduced prepatent period, increased worm burden and faecal egg output coupled with significantly greater anaemia and loss of body weight. It is suggested that in the tsetse or trypanosomosis endemic areas like southern Nigeria, grazing animals likely to harbour sub-clinical H. contortus infections may need to be prophylactically treated against concurrent trypanosome infection in order to maintain optimal productivity.

Keywords: Concurrent infection, haemonchosis, trypanosomosis, goats

Sahel Journal of Veterinary Sciences Vol. 5 (1) 2006 pp. 45-54