Land use and soil type determine the presence of the pathogen Burkholderia pseudomallei in tropical rivers

Olivier Ribolzi (1) , Emma Rochelle-Newall (2) , Sabine Dittrich (3, 4) , Yves Auda (1) , Paul N. Newton (3, 4) , Sayaphet Rattanavong (4) , Michael Knappik (3, 4) , Bounsamai Soulileuth (5) , Oloth Sengtaheuanghoung (6) , David A. B. Dance (3, 4) , Alain Pierret (7)

1 GET - Géosciences Environnement Toulouse
2 iEES Paris - Institut d'écologie et des sciences de l'environnement de Paris
3 University of Oxford
4 Mahosot Hospital
5 Institut de Recherche pour le Développement
6 DALam - Département of Agricultural Land Management
7 Inst Ecol & Environm Sci Paris, Inst Rech Dev, Viangchan, Laos

Burkholderia pseudomallei is the bacterium that causes melioidosis in humans. While B. pseudomallei is known to be endemic in South East Asia (SEA), the occurrence of the disease in other parts of the tropics points towards a potentially large global distribution. We investigated the environmental factors that influence the presence (and absence) of B. pseudomallei in a tropical watershed in SEA. Our main objective was to determine whether there is a link between the presence of the organism in the hydrographic network and the upstream soil and land-use type. The presence of B. pseudomallei was determined using a specific quantitative real-time PCR assay following enrichment culture. Land use, soil, geomorphology, and environmental data were then analyzed using partial least squares discriminant analysis (PLSDA) to compare the B. pseudomallei positive and negative sites. Soil type in the surrounding catchment and turbidity had a strong positive influence on the presence (acrisols and luvisols) or absence (ferralsols) of B. pseudomallei. Given the strong apparent links between soil characteristics, water turbidity, and the presence/absence of B. pseudomallei, actions to raise public awareness about factors increasing the risk of exposure should be undertaken in order to reduce the incidence of melioidosis in regions of endemicity.

Mots clés: Melioidosis; Ferralsols; Turbidity of river water; South East Asia; Partial least squares discriminant analysis (PLSDA); Geographical information system (GIS); Watershed

Mots clés: Acrisols

Domaines: Sciences du Vivant [q-bio]

Olivier Ribolzi, Emma Rochelle-Newall, Sabine Dittrich, Yves Auda, Paul N. Newton, et al.. Land use and soil type determine the presence of the pathogen Burkholderia pseudomallei in tropical rivers. Environmental Science and Pollution Research, 2016, 23 (8), pp.7828-7839. ⟨10.1007/s11356-015-5943-z⟩. ⟨hal-02634290⟩