Current status of tsetse fly and animal trypanosomosis on the Jos Plateau, Nigeria

Blood samples were collected from 1035 systematically selected zebu (White Fulani) cattle resident in two Local Government Areas (LGAs) of the Jos Plateau, and analysed for infections with trypanosomes. Their grazing grounds were also sampled for tsetse flies using unbaited blue Challier (biconical) traps. Mean prevalence of trypanosome infection was 6.4% (95% confidence interval (CI) ± 0.02) and 9.1% (CI ± 0.02) in Barkin-Ladi and Bassa LGAs, respectively. Higher infection rate was recorded during the rains (9.3%; CI ± 0.02) than in the dry season months (1.5%; CI ± 0.02). In both localities prevalence in cows (8.9%; CI ± 0.04) consistently doubled that in bulls (4.0%; CI ± 0.01). Also, infection rates increased with age until the 7th year. Trypanosoma vivax was both the predominant species and the only one diagnosed among yearlings. Only riverine tsetse species were encountered (apparently at low density) as infected vectors.