Variations saisonnières et facteurs de risques des trypanosomoses animales dans un contexte de chimiorésistance dans la zone de Sikasso au Mali

Three longitudinal surveys were carried out on cattle between August 2003 and April 2004 around Sikasso in Mali. The goal was to make a seasonal epidemiological assessment of the animal trypanosomoses in a chemoresistance context. From a parasitological viewpoint, heterogeneity exists in the evolution of the disease. High parasitological prevalences were recorded during the rainy season (August) at Diassadiè (34%) and at Wahibéra (28.89%). These two villages were the only to present a significant seasonal variation (p<0.05) of the observed prevalence values. The infections were mostly caused by Trypanosoma congolense (64.81 - 67.12%), followed by Trypanosoma vivax (28.77 - 35.19%) and rarely by Trypanosoma brucei (1.37%). The hematocrit average value was the highest in the rainy season (26.49% + 0.43) with a significant seasonal variation. Entomologically, two species of tsetse flies were identified during all seasons with apparent fly densities per trap (DAP) of 3.45 to 5.29 for Glossina palpalis gambiensis and 0.98 to 2.80 for Glossina tachinoides. A significant correlation (a =0.05) between the density of Glossina palpalis gambiensis and the rate of infection on the cattle was observed during the rainy season. Diminazene aceturate treatment failures (resistance) were suspected in several sites.