title: Spatial and temporal distribution of soil-transmitted helminth infection in sub-Saharan Africa: a systematic review and geostatistical meta-analysis.
abstract: BACKGROUND
  Interest is growing in predictive risk mapping for neglected tropical diseases (NTDs), particularly to scale up preventive chemotherapy, surveillance, and elimination efforts. Soil-transmitted helminths (hookworm, Ascaris lumbricoides, and Trichuris trichiura) are the most widespread NTDs, but broad geographical analyses are scarce. We aimed to predict the spatial and temporal distribution of soil-transmitted helminth infections, including the number of infected people and treatment needs, across sub-Saharan Africa.
  
  
  METHODS
  We systematically searched PubMed, Web of Knowledge, and African Journal Online from inception to Dec 31, 2013, without language restrictions, to identify georeferenced surveys. We extracted data from household surveys on sources of drinking water, sanitation, and women's level of education. Bayesian geostatistical models were used to align the data in space and estimate risk of with hookworm, A lumbricoides, and T trichiura over a grid of roughly 1 million pixels at a spatial resolution of 5 × 5 km. We calculated anthelmintic treatment needs on the basis of WHO guidelines (treatment of all school-aged children once per year where prevalence in this population is 20-50% or twice per year if prevalence is greater than 50%).
  
  
  RESULTS
  We identified 459 relevant survey reports that referenced 6040 unique locations. We estimate that the prevalence of hookworm, A lumbricoides, and T trichiura among school-aged children from 2000 onwards was 16·5%, 6·6%, and 4·4%. These estimates are between 52% and 74% lower than those in surveys done before 2000, and have become similar to values for the entire communities. We estimated that 126 million doses of anthelmintic treatments are required per year.
  
  
  CONCLUSIONS
  Patterns of soil-transmitted helminth infection in sub-Saharan Africa have changed and the prevalence of infection has declined substantially in this millennium, probably due to socioeconomic development and large-scale deworming programmes. The global control strategy should be reassessed, with emphasis given also to adults to progress towards local elimination.
  
  
  BACKGROUND
  Swiss National Science Foundation and European Research Council.
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Dimitrios-Alexios
authors.initials: DA
authors.lastname: Karagiannis-Voules
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; 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 Schistosomiases, Environnement, Aménagements et Lutte, Niamey, Niger.
authors.forename: Amadou
authors.initials: A
authors.lastname: Garba
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Erika
authors.initials: E
authors.lastname: Langer
authors.affiliation: Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Els
authors.initials: E
authors.lastname: Mathieu
authors.affiliation: Department of Medical Microbiology, College of Health Sciences, University of Zimbabwe, 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: Department of Parasitology, Leiden University Medical Centre, Leiden, Netherlands.
authors.forename: Anton M
authors.initials: AM
authors.lastname: Polderman
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Raso
authors.affiliation: Institut National de Recherche en Santé Publique, Bamako, Mali.
authors.forename: Moussa
authors.initials: M
authors.lastname: Sacko
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 I, Yaoundé, Cameroon; 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, Basel, Switzerland; 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, Basel, Switzerland; 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, Basel, Switzerland; University of Basel, Basel, Switzerland. Electronic address: penelope.vounatsou@unibas.ch.
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
mesh_terms: D017954:Africa South of the Sahara / Q000453:epidemiology; D000723:Ancylostomatoidea / Q000302:isolation & purification; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use; D017164:Ascaris lumbricoides / Q000302:isolation & purification; D006373:Helminthiasis / Q000188:drug therapy / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control; D058069:Neglected Diseases / Q000188:drug therapy / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control; D015995:Prevalence; D062211:Spatio-Temporal Analysis; D014258:Trichuris / Q000302:isolation & purification
chemical_list: D000871:Anthelmintics