Since the publication of the Millennium Ecosystem Assessment (2005) report, there has been an increased attention to the links between biodiversity, ecosystem services and human wellbeing. The EU and many other countries supported the recognition of the “One Health” approach in the decision; the African Group stressed the need to explain the links between biodiversity and epidemic diseases[. We will investigate how biodiversity conditions (dis)favour spill-over of infectious agents into human populations in African forests. This is crucial for predicting and controlling the risk of new outbreaks under changing biodiversity scenarios. In order to investigate this process, we propose 1° to link changes in biodiversity to changes in communities of reservoirs and the pathogens they carry and 2° to link differences in these reservoir communities to human health. The proposed research activities will focus on Monkeypox and Ebola viruses but a broader spectrum of pathogens will be included so that we can cover a range from pathogens that are relatively common in a variety of small mammals (MPXV) to pathogens that are rare and found in very few species only (EBV). The proposed study will be conducted in DR Congo and Côte d’Ivoire, in areas where these emerging diseases have been observed before and make optimal use of the large sample collections that have been collected earlier in these areas by the consortium partners.