OBSERVATIONS ON THE PREVALENCE OF TRYPANOSOMOSIS IN SMALL RUMINANTS, EQUINES AND CATTLE, IN RELATION TO TSETSE CHALLENGE, IN THE GAMBIA

The prevalence of trypanosome infections in Djallonke sheep and West A frican Dwarf goals at different sites in The Gambia showed a significa nt, positive correlation with contemporary assessments of tsetse chall enge. A similar correlation was observed in village N'Dama cattle whic h showed comparable prevalence values in the same areas. Trypanosome p revalences also tended to be higher in horses and donkeys in areas wit h high tsetse challenge compared with sites with relatively few flies. A ranking of the numbers of tsetse blood-meals from cattle, small rum inants and equines (1:0.06: > 0.03) corresponded with the estimated bi omass of these livestock groups (1:0.09:0.05), Observations on the gra zing ranges of livestock showed that, while cattle foraged widely into tsetse-infested habitat, sheep, goats and donkeys remained closer to the villages, This difference indicated that, under the management sys tem practised in The Gambia, small ruminants and equines were probably exposed to a lower level of tsetse attack than cattle.