F. Damico et al., ARE STABLE FLIES (DIPTERA, STOMOXYINAE) VECTORS OF TRYPANOSOMA-VIVAX IN THE CENTRAL-AFRICAN-REPUBLIC, Veterinary research, 27(2), 1996, pp. 161-170
The epidemiology of Trypanosoma vivax infections was studied at a rive
rside site in the Ouro-Djafoun livestock area situated in the Central
African Republic during the period between July 1991 and July 1992. Th
is paper examines the possibility that stable flies (Diptera: Stomoxyi
nae) were also vectors of this trypanosome species in a non-cyclic way
. Previous studies have revealed that the usual cyclic transmission by
the tsetse fly Glossina fuscipes fuscipes was probably not the only t
ransmission route. At the study site, at least five species or subspec
ies of stable flies were encountered: Stomoxys nigra nigra (approximat
ely 60% of the sample), S taeniata, S sitiens, S omega omega and Haema
tobia spp. The hypothesis that stable flies could be good vectors of T
vivax this country is supported by three main observations: i) stable
flies were very abundant at the cattle resting site; ii) an estimatio
n of the 'contact index' between the cattle and stable flies demonstra
ted close interactions between cattle and stable flies at this site, p
articularly during the rainy season, and iii) there was a good correla
tion (P < 0.05) between the apparent stable fly densities at the resti
ng site and the frequency of T vivax in the cattle. The relevance of t
his phenomenon in terms of epidemiology and combatting T vivax-caused
nagana is discussed.