title: Bayesian risk profiling of soil-transmitted helminth infections and estimates of preventive chemotherapy for school-aged children in Côte d'Ivoire.
abstract: BACKGROUND
  Soil-transmitted helminthiasis affects more than a billion people in the world and accounts for a global burden of 5.1 million disability-adjusted life years. The objectives of this study were (i) to map and predict the risk of soil-transmitted helminth infections among school-aged children in Côte d'Ivoire; (ii) to estimate school-aged children population-adjusted risk; and (iii) to estimate annual needs for preventive chemotherapy.
  
  
  METHODS
  In late 2011/early 2012, a cross-sectional survey was carried out among school-aged children in 92 localities of Côte d'Ivoire. Children provided a single stool sample that was subjected to duplicate Kato-Katz thick smears for the diagnosis of soil-transmitted helminths. A Bayesian geostatistical variable selection approach was employed to identify environmental and socioeconomic risk factors for soil-transmitted helminth infections. Bayesian kriging was used to predict soil-transmitted helminth infections on a grid of 1 × 1 km spatial resolution. The number of school-aged children infected with soil-transmitted helminths and the amount of doses needed for preventive chemotherapy according to World Health Organization guidelines were estimated.
  
  
  RESULTS
  Parasitological data were available from 5246 children aged 5-16 years. Helminth infections with hookworm were predominant (17.2 %). Ascaris lumbricoides and Trichuris trichiura were rarely found; overall prevalences were 1.9 % and 1.2 %, respectively. Bayesian geostatistical variable selection identified rural setting for hookworm, soil acidity and soil moisture for A. lumbricoides, and rainfall coefficient of variation for T. trichiura as main predictors of infection. The estimated school-aged children population-adjusted risk of soil-transmitted helminth infection in Côte d'Ivoire is 15.5 % (95 % confidence interval: 14.2-17.0 %). We estimate that approximately 1.3 million doses of albendazole or mebendazole are required for school-based preventive chemotherapy, and we provide school-aged children-adjusted risk aggregated at health district level.
  
  
  CONCLUSIONS
  We provide the first soil-transmitted helminthiasis risk profile for entire Côte d'Ivoire, based on a robust Bayesian geostatistical framework. Our model-based estimates of treatment needs and risk maps on health district level may guide the national control program in spatial targeting of annual interventions.
authors.affiliation: Unité de Formation et de Recherches Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.|Département Mode de Vie, Maladies Tropicales et Emergentes, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.|Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Yapi
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Chammartin
authors.affiliation: Département Mode de Vie, Maladies Tropicales et Emergentes, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.|Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Eveline
authors.initials: E
authors.lastname: Hürlimann
authors.affiliation: Département Mode de Vie, Maladies Tropicales et Emergentes, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.|Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.|Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d'Ivoire.
authors.forename: Clarisse A
authors.initials: CA
authors.lastname: Houngbedji
authors.affiliation: Département Mode de Vie, Maladies Tropicales et Emergentes, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.|Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Prisca B
authors.initials: PB
authors.lastname: N'Dri
authors.affiliation: Unité de Formation et de Recherches Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.|Département Mode de Vie, Maladies Tropicales et Emergentes, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.
authors.forename: Kigbafori D
authors.initials: KD
authors.lastname: Silué
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Unité de Formation et de Recherches Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.|Département Mode de Vie, Maladies Tropicales et Emergentes, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.
authors.forename: Eliézer K
authors.initials: EK
authors.lastname: N'Goran
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. giovanna.raso@unibas.ch.|University of Basel, Basel, Switzerland. giovanna.raso@unibas.ch.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Raso
mesh_terms: D000368:Aged; D000723:Ancylostomatoidea / Q000302:isolation & purification; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D017164:Ascaris lumbricoides / Q000302:isolation & purification; D001499:Bayes Theorem; D018890:Chemoprevention / Q000379:methods*; D002648:Child; D007560:Cote d'Ivoire / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005243:Feces / Q000469:parasitology; D006373:Helminthiasis / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control*; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control*; D010274:Parasitology / Q000379:methods; D018570:Risk Assessment; D012574:Schools; D013334:Students; D019371:Topography, Medical; D014258:Trichuris / Q000302:isolation & purification
chemical_list: D000871:Anthelmintics
keywords: Bayesian modelling; Côte d’Ivoire; Hookworm; Risk profiling; School-aged children; Soil-transmitted helminthiasis