NEW EPIDEMIOLOGIC FEATURES ON ANIMAL TRYPANOSOMIASIS BY MOLECULAR ANALYSIS IN THE PASTORAL ZONE OF SIDERADOUGOU, BURKINA-FASO

A multidisciplinary work was undertaken in the agropastoral zone of Si deradougou, Burkina Faso to try to elucidate the key factors determini ng the presence of tsetse flies. In this study the PCR was used to cha racterize trypanosomes infecting the vector (Glossina tachinoines and Glossina palpalis gambiensis) and the host, i.e. cattle. A 2-year surv ey involved dissecting 2211 tsetse of the two Glossina species. A tota l of 298 parasitologically infected tsetse were analysed by PCR. Trypa nosoma viz,nx was the most frequently identified trypanosome followed by the savannah type of T. congolense and, to a lesser extent, the riv erine forest type of T. congolense, and by T. brucei. No cases of T. s imiae were found. From the 107 identified infections in cattle, the ta xa were the same, but T. congolense savannah type was more frequent, w hereas T. vivax and T. congolense riverine forest types were found les s frequently. A correlation was found between midgut infection rates o f tsetse, nonidentified infections and reptile bloodmeals. These rates were higher in G.p. gambiensis, and in the western part of the study area. T. vivax infections were related to cattle bloodmeals, and were more frequent in G. tachinoides and in the eastern study area. The PCR results combined with bloodmeal analysis helped us to establish the r elationships between the vector and the host, to assess the trypanosom e challenge in the two parts of the area, to elucidate the differences between the two types of T. congolense, and to suspect that most midg ut infections were originating from reptilian trypanosomes.