Buruli ulcer is a neglected tropical disease caused by M. ulcerans, an environmental mycobacterium. This cutaneous infectious disease affects populations with poor access to sanitation, safe water and healthcare living in rural areas of West and Central Africa. Stagnant open bodies of surface water and slow-running streams are the risk factor identified in Africa, and there is no human-to-human transmission. This is reflected by spatially differentiated variations in incidence. The Ouémé/Plateau region in southeastern Benin is particularly affected by these health inequalities. To gain a deeper understanding of the variation in incidence, our team used mixed methods research: the definition and observation of sources of water as well as water bodies and streams used by the communities, field observations, case-control studies, spatial analysis, and the analysis of environmental samples. This work provides a set of new clues on the simultaneous role of social and environmental determinants responsible for the dynamics of the disease. 1: visiting daily activities places with respondents conduct them to mention places and behaviors at risk of exposure that they would not spontaneously evocate in a traditional interview guide 2: By shifting the focus from water points used for domestic activities (traditionally recognised as the main cause of many water-borne diseases) to the search for areas at risk of transmission, our cross-observations enabled us to draw up a typology of areas favourable to pathogens. Rather than looking for the absolute presence of M. ulcerans in the environment by taking samples, we can now work on bioindicators of exposure to assess health risks. 3: To reduce the risks of exposure, we now assume that solutions and adaptation scenarios must be based on the experiences of local communities, on their traditional organisation of space. To this end, our methodology is evolving in a ComMod (Companion modelling) approach.

Buruli ulcer is a neglected tropical disease caused by M. ulcerans, an environmental mycobacterium. This cutaneous infectious disease affects populations with poor access to sanitation, safe water and healthcare living in rural areas of West and Central Africa. Stagnant open bodies of surface water and slow-running streams are the risk factor identified in Africa, and there is no human-to-human transmission. This is reflected by spatially differentiated variations in incidence. The Ouémé/Plateau region in southeastern Benin is particularly affected by these health inequalities. To gain a deeper understanding of the variation in incidence, our team used mixed methods research: the definition and observation of sources of water as well as water bodies and streams used by the communities, field observations, case-control studies, spatial analysis, and the analysis of environmental samples. This work provides a set of new clues on the simultaneous role of social and environmental determinants responsible for the dynamics of the disease. 1: visiting daily activities places with respondents conduct them to mention places and behaviors at risk of exposure that they would not spontaneously evocate in a traditional interview guide 2: By shifting the focus from water points used for domestic activities (traditionally recognised as the main cause of many water-borne diseases) to the search for areas at risk of transmission, our cross-observations enabled us to draw up a typology of areas favourable to pathogens. Rather than looking for the absolute presence of M. ulcerans in the environment by taking samples, we can now work on bioindicators of exposure to assess health risks. 3: To reduce the risks of exposure, we now assume that solutions and adaptation scenarios must be based on the experiences of local communities, on their traditional organisation of space. To this end, our methodology is evolving in a ComMod (Companion modelling) approach.