title: Understanding Heterogeneity in the Impact of National Neglected Tropical Disease Control Programmes: Evidence from School-Based Deworming in Kenya.
abstract: BACKGROUND
  The implementation of soil-transmitted helminth (STH) treatment programmes occurs in varied environmental, social and economic contexts. Programme impact will be influenced by factors that affect the reduction in the prevalence and intensity of infections following treatment, as well as the subsequent rate of reinfection. To better understand the heterogeneity of programme impact and its underlying reasons, we investigated the influence of contextual factors on reduction in STH infection as part of the national school based deworming (SBD) programme in Kenya.
  
  
  METHODS
  Data on the prevalence and intensity of infection were collected within the monitoring and evaluation component of the SBD programme at baseline and after delivery of two annual treatment rounds in 153 schools in western Kenya. Using a framework that considers STH epidemiology and transmission dynamics, capacity to deliver treatment, operational feasibility and financial capacity, data were assembled at both school and district (county) levels. Geographic heterogeneity of programme impact was assessed by descriptive and spatial analyses. Factors associated with absolute reductions of Ascaris lumbricoides and hookworm infection prevalence and intensity were identified using mixed effects linear regression modelling adjusting for baseline infection levels.
  
  
  RESULTS
  The reduction in prevalence and intensity of A. lumbricoides and hookworms varied significantly by county and within counties by school. Multivariable analysis of factors associated with programme impact showed that absolute A. lumbricoides reductions varied by environmental conditions and access to improved sanitation at schools or within the community. Larger reduction in prevalence and intensity of hookworms were found in schools located within areas with higher community level access to improved sanitation and within counties with higher economic and health service delivery indicator scores.
  
  
  CONCLUSIONS
  The study identifies factors associated with the impact of school-based deworming and in particular highlights how access to water, sanitation and hygiene and environmental conditions influence the impact of deworming programmes.
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors.forename: Birgit
authors.initials: B
authors.lastname: Nikolay
authors.affiliation: Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya.
authors.forename: Charles S
authors.initials: CS
authors.lastname: Mwandawiro
authors.affiliation: Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya.
authors.forename: Jimmy H
authors.initials: JH
authors.lastname: Kihara
authors.affiliation: Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya.
authors.forename: Collins
authors.initials: C
authors.lastname: Okoyo
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors.forename: Jorge
authors.initials: J
authors.lastname: Cano
authors.affiliation: Neglected Tropical Diseases Unit, Division of Communicable Disease Prevention and Control, Ministry of Health, Nairobi, Kenya.
authors.forename: Mariam T
authors.initials: MT
authors.lastname: Mwanje
authors.affiliation: Neglected Tropical Diseases Unit, Division of Communicable Disease Prevention and Control, Ministry of Health, Nairobi, Kenya.
authors.forename: Hadley
authors.initials: H
authors.lastname: Sultani
authors.affiliation: Neglected Tropical Diseases Unit, Division of Communicable Disease Prevention and Control, Ministry of Health, Nairobi, Kenya.
authors.forename: Dorcas
authors.initials: D
authors.lastname: Alusala
authors.affiliation: London Centre for Neglected Tropical Disease Research, London, United Kingdom; Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom.
authors.forename: Hugo C
authors.initials: HC
authors.lastname: Turner
authors.affiliation: Evidence Action, Nairobi, Kenya.
authors.forename: Caroline
authors.initials: C
authors.lastname: Teti
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Josh
authors.initials: J
authors.lastname: Garn
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Freeman
authors.affiliation: Department of Medical Statistics, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Allen
authors.affiliation: London Centre for Neglected Tropical Disease Research, London, United Kingdom; Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom.
authors.forename: Roy M
authors.initials: RM
authors.lastname: Anderson
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Pullan
authors.affiliation: Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya.
authors.forename: Sammy M
authors.initials: SM
authors.lastname: Njenga
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Brooker
mesh_terms: D000724:Ancylostomiasis / Q000453:epidemiology / Q000628:therapy / Q000635:transmission; D000818:Animals; D000969:Antinematodal Agents / Q000008:administration & dosage*; D001196:Ascariasis / Q000453:epidemiology / Q000628:therapy / Q000635:transmission; D003695:Delivery of Health Care; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D058069:Neglected Diseases / Q000453:epidemiology / Q000628:therapy*; D009349:Nematode Infections / Q000453:epidemiology* / Q000628:therapy*; D015995:Prevalence; D015397:Program Evaluation; D011634:Public Health; D012572:School Health Services / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors; D014257:Trichuriasis / Q000453:epidemiology / Q000628:therapy; D014867:Water / Q000469:parasitology
chemical_list: D000969:Antinematodal Agents; D014867:Water