PLoS Medicine (Nov 2016)

Exposure Patterns Driving Ebola Transmission in West Africa: A Retrospective Observational Study.

  • International Ebola Response Team,
  • Junerlyn Agua-Agum,
  • Archchun Ariyarajah,
  • Bruce Aylward,
  • Luke Bawo,
  • Pepe Bilivogui,
  • Isobel M Blake,
  • Richard J Brennan,
  • Amy Cawthorne,
  • Eilish Cleary,
  • Peter Clement,
  • Roland Conteh,
  • Anne Cori,
  • Foday Dafae,
  • Benjamin Dahl,
  • Jean-Marie Dangou,
  • Boubacar Diallo,
  • Christl A Donnelly,
  • Ilaria Dorigatti,
  • Christopher Dye,
  • Tim Eckmanns,
  • Mosoka Fallah,
  • Neil M Ferguson,
  • Lena Fiebig,
  • Christophe Fraser,
  • Tini Garske,
  • Lice Gonzalez,
  • Esther Hamblion,
  • Nuha Hamid,
  • Sara Hersey,
  • Wes Hinsley,
  • Amara Jambei,
  • Thibaut Jombart,
  • David Kargbo,
  • Sakoba Keita,
  • Michael Kinzer,
  • Fred Kuti George,
  • Beatrice Godefroy,
  • Giovanna Gutierrez,
  • Niluka Kannangarage,
  • Harriet L Mills,
  • Thomas Moller,
  • Sascha Meijers,
  • Yasmine Mohamed,
  • Oliver Morgan,
  • Gemma Nedjati-Gilani,
  • Emily Newton,
  • Pierre Nouvellet,
  • Tolbert Nyenswah,
  • William Perea,
  • Devin Perkins,
  • Steven Riley,
  • Guenael Rodier,
  • Marc Rondy,
  • Maria Sagrado,
  • Camelia Savulescu,
  • Ilana J Schafer,
  • Dirk Schumacher,
  • Thomas Seyler,
  • Anita Shah,
  • Maria D Van Kerkhove,
  • C Samford Wesseh,
  • Zabulon Yoti

DOI
https://doi.org/10.1371/journal.pmed.1002170
Journal volume & issue
Vol. 13, no. 11
p. e1002170

Abstract

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BackgroundThe ongoing West African Ebola epidemic began in December 2013 in Guinea, probably from a single zoonotic introduction. As a result of ineffective initial control efforts, an Ebola outbreak of unprecedented scale emerged. As of 4 May 2015, it had resulted in more than 19,000 probable and confirmed Ebola cases, mainly in Guinea (3,529), Liberia (5,343), and Sierra Leone (10,746). Here, we present analyses of data collected during the outbreak identifying drivers of transmission and highlighting areas where control could be improved.Methods and findingsOver 19,000 confirmed and probable Ebola cases were reported in West Africa by 4 May 2015. Individuals with confirmed or probable Ebola ("cases") were asked if they had exposure to other potential Ebola cases ("potential source contacts") in a funeral or non-funeral context prior to becoming ill. We performed retrospective analyses of a case line-list, collated from national databases of case investigation forms that have been reported to WHO. These analyses were initially performed to assist WHO's response during the epidemic, and have been updated for publication. We analysed data from 3,529 cases in Guinea, 5,343 in Liberia, and 10,746 in Sierra Leone; exposures were reported by 33% of cases. The proportion of cases reporting a funeral exposure decreased over time. We found a positive correlation (r = 0.35, p ConclusionsAchieving elimination of Ebola is challenging, partly because of super-spreading. Safe funeral practices and fast hospitalisation contributed to the containment of this Ebola epidemic. Continued real-time data capture, reporting, and analysis are vital to track transmission patterns, inform resource deployment, and thus hasten and maintain elimination of the virus from the human population.