title: Land use and soil type determine the presence of the pathogen Burkholderia pseudomallei in tropical rivers.
abstract: 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.
authors.affiliation: Géosciences Environnement Toulouse (GET), UMR 5563, (IRD, CNRS, UPS), Université de Toulouse, UPS (OMP), CNRS, Toulouse, France. olivier.ribolzi@ird.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Ribolzi
authors.affiliation: iEES-Paris (IRD-UPMC-CNRS-INRA-UDD-UPEC), Sorbonne Universités, UPMC Univ Paris 06, Institut de Recherche pour le Développement (IRD), case 23, 4 place Jussieu, Paris cedex, 75252, France.
authors.forename: Emma
authors.initials: E
authors.lastname: Rochelle-Newall
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic.|Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
authors.forename: Sabine
authors.initials: S
authors.lastname: Dittrich
authors.affiliation: Géosciences Environnement Toulouse (GET), UMR 5563, (IRD, CNRS, UPS), Université de Toulouse, UPS (OMP), CNRS, Toulouse, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Auda
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic.|Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Newton
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic.
authors.forename: Sayaphet
authors.initials: S
authors.lastname: Rattanavong
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic.|Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Knappik
authors.affiliation: Institute of Ecology and Environmental Science-Paris, Institut de Recherche pour le Développement (IRD), Vientiane, Lao People's Democratic Republic.
authors.forename: Bounsamai
authors.initials: B
authors.lastname: Soulileuth
authors.affiliation: Department of Agricultural Land Management (DALaM), P.O. Box 4199, Ban Nogviengkham, Xaythany District, Vientiane, Lao People's Democratic Republic.
authors.forename: Oloth
authors.initials: O
authors.lastname: Sengtaheuanghoung
authors.affiliation: Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic.|Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
authors.forename: David A B
authors.initials: DA
authors.lastname: Dance
authors.affiliation: Institute of Ecology and Environmental Science-Paris, Institut de Recherche pour le Développement (IRD), Vientiane, Lao People's Democratic Republic.
authors.forename: Alain
authors.initials: A
authors.lastname: Pierret
mesh_terms: D016957:Burkholderia pseudomallei / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D060888:Real-Time Polymerase Chain Reaction; D045483:Rivers / Q000382:microbiology*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D014329:Tropical Climate
chemical_list: D012987:Soil
keywords: Acrisols; Ferralsols; Geographical information system (GIS); Melioidosis; Partial least squares discriminant analysis (PLSDA); South East Asia; Turbidity of river water; Watershed