title: Bayesian geostatistical model-based estimates of soil-transmitted helminth infection in Nigeria, including annual deworming requirements.
abstract: BACKGROUND
  The acceleration of the control of soil-transmitted helminth (STH) infections in Nigeria, emphasizing preventive chemotherapy, has become imperative in light of the global fight against neglected tropical diseases. Predictive risk maps are an important tool to guide and support control activities.
  
  
  METHODS
  STH infection prevalence data were obtained from surveys carried out in 2011 using standard protocols. Data were geo-referenced and collated in a nationwide, geographic information system database. Bayesian geostatistical models with remotely sensed environmental covariates and variable selection procedures were utilized to predict the spatial distribution of STH infections in Nigeria.
  
  
  RESULTS
  We found that hookworm, Ascaris lumbricoides, and Trichuris trichiura infections are endemic in 482 (86.8%), 305 (55.0%), and 55 (9.9%) locations, respectively. Hookworm and A. lumbricoides infection co-exist in 16 states, while the three species are co-endemic in 12 states. Overall, STHs are endemic in 20 of the 36 states of Nigeria, including the Federal Capital Territory of Abuja. The observed prevalence at endemic locations ranged from 1.7% to 51.7% for hookworm, from 1.6% to 77.8% for A. lumbricoides, and from 1.0% to 25.5% for T. trichiura. Model-based predictions ranged from 0.7% to 51.0% for hookworm, from 0.1% to 82.6% for A. lumbricoides, and from 0.0% to 18.5% for T. trichiura. Our models suggest that day land surface temperature and dense vegetation are important predictors of the spatial distribution of STH infection in Nigeria. In 2011, a total of 5.7 million (13.8%) school-aged children were predicted to be infected with STHs in Nigeria. Mass treatment at the local government area level for annual or bi-annual treatment of the school-aged population in Nigeria in 2011, based on World Health Organization prevalence thresholds, were estimated at 10.2 million tablets.
  
  
  CONCLUSIONS
  The predictive risk maps and estimated deworming needs presented here will be helpful for escalating the control and spatial targeting of interventions against STH infections in Nigeria.
authors.affiliation: Department of Biological Sciences, Federal University of Agriculture, Abeokuta, Nigeria.
authors.forename: Akinola S
authors.initials: AS
authors.lastname: Oluwole
authors.affiliation: Department of Biological Sciences, Federal University of Agriculture, Abeokuta, Nigeria.
authors.forename: Uwem F
authors.initials: UF
authors.lastname: Ekpo
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 Biological Sciences, Federal University of Agriculture, Abeokuta, Nigeria; Department of Zoology, Federal University, Lafia, Nigeria.
authors.forename: Eniola M
authors.initials: EM
authors.lastname: Abe
authors.affiliation: Mission to Save the Helpless (MITOSATH), Jos, Nigeria.
authors.forename: Francisca O
authors.initials: FO
authors.lastname: Olamiju
authors.affiliation: Sightsavers, Nigeria Country Office, Kaduna, Nigeria.
authors.forename: Sunday
authors.initials: S
authors.lastname: Isiyaku
authors.affiliation: Department of Public Health, Federal Ministry of Health, Abuja, Nigeria.
authors.forename: Chukwu
authors.initials: C
authors.lastname: Okoronkwo
authors.affiliation: Department of Public Health, Federal Ministry of Health, Abuja, Nigeria.
authors.forename: Yisa
authors.initials: Y
authors.lastname: Saka
authors.affiliation: Department of Public Health, Federal Ministry of Health, Abuja, Nigeria.
authors.forename: Obiageli J
authors.initials: OJ
authors.lastname: Nebe
authors.affiliation: Department of Zoology, Federal University, Lafia, Nigeria.
authors.forename: Eka I
authors.initials: EI
authors.lastname: Braide
authors.affiliation: National Universities Commission, Abuja, Nigeria.
authors.forename: Chiedu F
authors.initials: CF
authors.lastname: Mafiana
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.
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
mesh_terms: D000723:Ancylostomatoidea / Q000302:isolation & purification; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use; D017164:Ascaris lumbricoides / Q000302:isolation & purification; D001499:Bayes Theorem; D002648:Child; D005260:Female; D040362:Geographic Information Systems; D005843:Geography; D006373:Helminthiasis / Q000188:drug therapy* / Q000453:epidemiology* / Q000635:transmission*; D006801:Humans; D008297:Male; D008954:Models, Biological; D009549:Nigeria / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012987:Soil / Q000469:parasitology*; D014258:Trichuris / Q000302:isolation & purification
chemical_list: D000871:Anthelmintics; D012987:Soil