title: The global distribution and transmission limits of lymphatic filariasis: past and present.
abstract: BACKGROUND
  Lymphatic filariasis (LF) is one of the neglected tropical diseases targeted for global elimination by 2020 and to guide elimination efforts countries have, in recent years, conducted extensive mapping surveys. Documenting the past and present distribution of LF and its environmental limits is important for a number of reasons. Here, we present an initiative to develop a global atlas of LF and present a new global map of the limits of LF transmission.
  
  
  METHODS
  We undertook a systematic search and assembly of prevalence data worldwide and used a suite of environmental and climatic data and boosted regression trees (BRT) modelling to map the transmission limits of LF.
  
  
  RESULTS
  Data were identified for 66 of the 72 countries currently endemic and for a further 17 countries where LF is no longer endemic. Our map highlights a restricted and highly heterogeneous distribution in sub-Saharan Africa, with transmission more widespread in West Africa compared to east, central and southern Africa where pockets of transmission occur. Contemporary transmission occurs across much of south and South-east Asia and the Pacific. Interestingly, the risk map reflects environmental conditions suitable for LF transmission across Central and South America, including the southern States of America, although active transmission is only known in a few isolated foci. In countries that have eliminated LF, our predictions of environmental suitability are consistent with historical distribution.
  
  
  CONCLUSIONS
  The global distribution of LF is highly heterogeneous and geographically targeted and sustained control will be required to achieve elimination. This first global map can help evaluate the progress of interventions and guide surveillance activities.
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom. jcano.ortega@lshtm.ac.uk.
authors.forename: Jorge
authors.initials: J
authors.lastname: Cano
authors.affiliation: NTD Support Center, Task Force for Global Health, Emory University, Atlanta, United States of America. mrebollo@taskforce.org.|Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom. mrebollo@taskforce.org.
authors.forename: Maria P
authors.initials: MP
authors.lastname: Rebollo
authors.affiliation: Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK. nick.golding@linacre.ox.ac.uk.
authors.forename: Nick
authors.initials: N
authors.lastname: Golding
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom. Rachel.Pullan@lshtm.ac.uk.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Pullan
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom. tomcrellen@gmail.com.
authors.forename: Thomas
authors.initials: T
authors.lastname: Crellen
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom. anna.soler.colome@gmail.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Soler
authors.affiliation: Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom. L.Kelly-Hope@liverpool.ac.uk.
authors.forename: Louise A
authors.initials: LA
authors.lastname: Kelly-Hope
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom. s.w.lindsay@durham.ac.uk.
authors.forename: Steve W
authors.initials: SW
authors.lastname: Lindsay
authors.affiliation: Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK. simon.i.hay@gmail.com.
authors.forename: Simon I
authors.initials: SI
authors.lastname: Hay
authors.affiliation: Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom. Moses.Bockarie@liverpool.ac.uk.
authors.forename: Moses J
authors.initials: MJ
authors.lastname: Bockarie
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom. Simon.Brooker@lshtm.ac.uk.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Brooker
mesh_terms: D004605:Elephantiasis, Filarial / Q000453:epidemiology*; D019353:Endemic Diseases; D014943:Global Health; D006801:Humans; D012307:Risk Factors; D013997:Time Factors