Glossina fusca group tsetse as vectors of cattle trypanosomiasis in Gabon and Zaire

Abstract

1. The significance of Glossina fusca group tsetse flies as vectors of cattle trypanosomiasis was examined using biconical traps to survey tsetse populations at one site in Gabon and two sites in Zaire. 2. Mean trypanosome infection rates in G.tabaniformis Westwood over the study period ranged from a minimum of 8.9% at one site to a maximum of 17.7% at another. The mean infection rate in G.nashi Potts was 6.0%. 3. Up to 49% of bloodmeals of G.tabaniformis were from cattle. Trypanosome prevalence in cattle where G.tabaniformis appeared to be the main vector was 9.5% and 5.4% at the Mushie and OGAPROV ranches, respectively. 4. A highly significant positive correlation was found between tsetse challenge and trypanosome prevalence in N'Dama cattle across sites. Tsetse challenge was defined as the product of tsetse relative densities, trypanosome infection rates in the flies and the proportion of feeds taken by them from cattle. Thus, G.tabaniformis can be an important vector of pathogenic Trypanosoma species in cattle.

The dynamics of trypanosome infections in natural populations of tsetse (Diptera: Glossinidae) studied using wing-fray and ovarian ageing techniques

“…Glossina fuscipes ssp. had low trypanosome infection rates at all sites, confirming studies that have shown that this species is a poor vector of trypanosomes to domestic livestock (Harley & Wilson, 1968;Leak et al, 1991).…”

“…The high proportion of T. vivax-type infections observed in G. tabaniformis is interesting as this species has generally been found to feed predominantly on Suidae which are refractory to T. vivax infections (Jordan, 1965). In the work reported here, G. tabaniformis was found to take only 13% of its feeds from Suidae at the OGAPROV ranch and 8% at Mushie (Leak et al, 1991).…”

An analysis of survey measurements of tsetse challenge to trypanotolerant cattle in relation to aspects of analytical models of trypanosomiasis

“…The analyses of monthly and yearly changes in tsetse abundance, trypanosome infection rates in tsetse and trypanosome prevalence in cattle indicate that the general level of tsetse/trypanosomiasis challenge to trypanotolerant cattle can be closely related to the mean annual level of trypanosome prevalence in village-managed herds. This finding was in line with the results of similar investigations carried out at seven African Trypanotolerance Livestock Network study sites (Leak et al 1988(Leak et al , 1990. The majority of data collected in The Gambia related to challenge on a single breed of trypanotolerant cattle from a single species of tsetse, whereas the A T L N results covered several species of tsetse and various breeds of cattle.…”

Trypanosomiasis challenge estimation using the diminazene aceturate (Berenil) index in Zebu in Gabon

“…The average annual precipitation and temperature are of 2000 mm and 28 °C, respectively, with great yearly variations. The area was known for being a tsetse habitat in the 1990s with the presence of Glossina tabaniformis , Glossina palpalis and Glossina nashi at a low density (Leak et al 1991 ).…”