Human-induced Pressures and Environmental Factors Drive the Distribution of Neglected Tropical Disease Buruli Ulcer

BACKGROUND:Understanding the spatial distribution of skin neglected tropical diseases (NTDs) is paramount for surveillance and control strategies, although little is known regarding their natural origin, ecology, and distribution. This study aims to determine how natural and anthropogenic factors affect local to global spatial distribution patterns of a major skin NTD, Buruli ulcer (BU), and its pathogen, Mycobacterium ulcerans (MU). METHODS:Generalized linear modelling of 110 variables grouped into five categories (i.e., physical, edaphic/climatic, animal diversity, plant diversity, and socio-demographic/geographic) were used to estimate continental-scale patterns of both MU and BU cases in Africa. Spatial models allowed the production of BU and MU maps for tropical and subtropical zones worldwide. RESULTS:Natural factors and their interactions consistently influence MU and BU distributions in Africa, with these distributions also responding to anthropogenic factors such as invasive plant species, agriculture and other activities. BU case distribution was driven by sunlight radiation, especially UV-B seasonality. Our extrapolation maps provide a quantitative understanding of the potential distribution of this pathogen and associated BU disease burden. DISCUSSION:Our findings highlight the utility of a disease ecology perspective using large-scale spatial data for understanding drivers of skin NTDs. Complex interactions between natural and anthropogenic factors indicate that developing preventive and control measures is challenging. Particular attention is needed on the role of invasive plant species in the spread of these pathogens, and the complex influence of sun exposure on skin NTDs.