African animal trypanosomiasis (AAT), transmitted by the tsetse fly, is a climate sensitive animal disease that is a major obstacle to sustainable development of livestock husbandry and agriculture in sub-Saharan Africa. To address this problem, the African Union set up in 2000, the Pan-African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) to implement extensive campaigns of tsetse eradication across the continent and overcome this disease. In order to optimize these campaigns, we propose in this thesis two contributions.
The first is an understanding of the risk of AAT and the second is an improvement of ex-ante economic analysis of these projects. Therefore, we first developed a spatial risk analysis of trypanosomosis risk induced by climate and environment in order to guide the eradication campaign in the Niayes area in Senegal.
This model, compared to existing models, enabled complete tsetse eradication while using fewer resources such as traps and labor. Moreover, this risk analysis was refined in Burkina-Faso and Ghana to take into account seasonal climate variability. Finally, these risks models developed in this thesis were used in a bioeconomic model that combined also climate change projections and the results of a participatory workshop with herders in the Niayes area. This economic analysis showed that taking into account or not climate change projections has a great influence on the potential benefits of tsetse eradication. In the Niayes campaign, the model showed that the potential benefits were overestimated although the project is still profitable.
This analysis also highlighted another important result, in tsetse-free area cleared by the project, farmers innovated and replaced their herds of trypanotolerant cattle by more productive but trypanosusceptible herds, while reducing herd sizes.
Therefore, we can conclude that in the context of the eradication campaign in Niayes, reducing the risk of AAT could help to mitigate climate change by limiting the gases from cattle farming and could also allow the livestock system to adapt to anticipated global changes such as fodder shortage.