title: Spatial distribution of schistosomiasis and treatment needs in sub-Saharan Africa: a systematic review and geostatistical analysis.
abstract: BACKGROUND
  Schistosomiasis affects more than 200 million individuals, mostly in sub-Saharan Africa, but empirical estimates of the disease burden in this region are unavailable. We used geostatistical modelling to produce high-resolution risk estimates of infection with Schistosoma spp and of the number of doses of praziquantel treatment needed to prevent morbidity at different administrative levels in 44 countries.
  
  
  METHODS
  We did a systematic review to identify surveys including schistosomiasis prevalence data in sub-Saharan Africa via PubMed, ISI Web of Science, and African Journals Online, from inception to May 2, 2014, with no restriction of language, survey date, or study design. We used Bayesian geostatistical meta-analysis and rigorous variable selection to predict infection risk over a grid of 1 155 818 pixels at 5 × 5 km, on the basis of environmental and socioeconomic predictors and to calculate the number of doses of praziquantel needed for prevention of morbidity.
  
  
  RESULTS
  The literature search identified Schistosoma haematobium and Schistosoma mansoni surveys done in, respectively, 9318 and 9140 unique locations. Infection risk decreased from 2000 onwards, yet estimates suggest that 163 million (95% Bayesian credible interval [CrI] 155 million to 172 million; 18·5%, 17·6-19·5) of the sub-Saharan African population was infected in 2012. Mozambique had the highest prevalence of schistosomiasis in school-aged children (52·8%, 95% CrI 48·7-57·8). Low-risk countries (prevalence among school-aged children lower than 10%) included Burundi, Equatorial Guinea, Eritrea, and Rwanda. The numbers of doses of praziquantel needed per year were estimated to be 123 million (95% CrI 121 million to 125 million) for school-aged children and 247 million (239 million to 256 million) for the entire population.
  
  
  CONCLUSIONS
  Our results will inform policy makers about the number of treatments needed at different levels and will guide the spatial targeting of schistosomiasis control interventions.
  
  
  BACKGROUND
  European Research Council, China Scholarship Council, UBS Optimus Foundation, and Swiss National Science Foundation.
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Ying-Si
authors.initials: YS
authors.lastname: Lai
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Patricia
authors.initials: P
authors.lastname: Biedermann
authors.affiliation: Department of Biological Sciences, Federal University of Agriculture, Abeokuta, Nigeria.
authors.forename: Uwem F
authors.initials: UF
authors.lastname: Ekpo
authors.affiliation: Réseau International Schistosomose, Environnement, Amenagement et Lutte, Niamey, Niger.
authors.forename: Amadou
authors.initials: A
authors.lastname: Garba
authors.affiliation: National Center of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Els
authors.initials: E
authors.lastname: Mathieu
authors.affiliation: National Institute of Health Research, Harare, Zimbabwe.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Midzi
authors.affiliation: Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
authors.forename: Pauline
authors.initials: P
authors.lastname: Mwinzi
authors.affiliation: Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire; 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, and University of Basel, Basel, Switzerland.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Raso
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.
authors.forename: Rufin K
authors.initials: RK
authors.lastname: Assaré
authors.affiliation: Institut National de Recherche en Santé Publique, Bamako, Mali.
authors.forename: Moussa
authors.initials: M
authors.lastname: Sacko
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Nadine
authors.initials: N
authors.lastname: Schur
authors.affiliation: Direction de la Lutte Contre la Maladie, Ministère de la Santé, Dakar, Senegal.
authors.forename: Idrissa
authors.initials: I
authors.lastname: Talla
authors.affiliation: Laboratory of Parasitology and Ecology, University of Yaoundé, and Center for Schistosomiasis and Parasitology, Yaoundé, Cameroon.
authors.forename: Louis-Albert Tchuem
authors.initials: LA
authors.lastname: Tchuenté
authors.affiliation: Programme National de Lutte Contre la Schistosomiase, Ministère de la Santé, Ouagadougou, Burkina Faso.
authors.forename: Seydou
authors.initials: S
authors.lastname: Touré
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Mirko S
authors.initials: MS
authors.lastname: Winkler
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland. Electronic address: penelope.vounatsou@unibas.ch.
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
mesh_terms: D000293:Adolescent; D017954:Africa South of the Sahara / Q000453:epidemiology; D000818:Animals; D001499:Bayes Theorem; D002648:Child; D002675:Child, Preschool; D006301:Health Services Needs and Demand; D006801:Humans; D009017:Morbidity; D009073:Mozambique; D011223:Praziquantel / Q000627:therapeutic use; D015995:Prevalence; D012548:Schistosoma haematobium / Q000187:drug effects; D012550:Schistosoma mansoni / Q000187:drug effects; D012552:Schistosomiasis / Q000188:drug therapy / Q000453:epidemiology*
chemical_list: D011223:Praziquantel