Entomological and parasitological current situation of African animal trypanosomosis in the Cascades Region, Burkina Faso

In Sub-Saharan countries infested with tsetse flies, African Animal Trypanosomosis is considered as the primary pathological constraint in bovine farming. This study aimed to assess the epidemiological risk of trypanosomosis in four departments of the Special Economic Zone in Burkina Faso, namely Loumana, Niankorodougou, Ouéléni and Niangoloko. The study carried out from December 2022 to February 2023 and combined parasitological and entomological investigations. For the parasitological survey, 704 cows were sampled, and examination using the Buffy-Coat method. For the entomological component, in each village, two tsetse prospection sites were selected and at each site, two biconical traps were set for 72 hours. The parasitological analysis revealed 49 positive cases, resulting in a prevalence of 6.68% (CI: 4.83 - 8.52%). Analysis by department showed the highest prevalence in Loumana (11.60%), which was significantly different from the other three departments (p < 0.03), (Niangoloko (2.58%), Ouéléni (3.23%) and Niankorodougou (6.25%). Two species of trypanosomes were responsible for the infections, Trypanosoma (T.) congolense and T. vivax, with T. congolense being the predominant species (6.68%). A total of 135 tsetse flies were captured, with an overall apparent density of 0.79 flies per trap per day. Glossina palpalis gambiense was the only species encountered. Mechanical vectors were also captured at a low density, with 0.32 flies per trap per day. This study indicates that while the landscape fragmentation is associated with a reduction in tsetse fly species diversity, the trypanosomiasis risk remains significant, as evidenced by the high prevalence in animals.