Reduced evolutionary rate in reemerged Ebola virus transmission chains

Sci Adv. 2016 Apr 29;2(4):e1600378. doi: 10.1126/sciadv.1600378. eCollection 2016 Apr.

Abstract

On 29 June 2015, Liberia's respite from Ebola virus disease (EVD) was interrupted for the second time by a renewed outbreak ("flare-up") of seven confirmed cases. We demonstrate that, similar to the March 2015 flare-up associated with sexual transmission, this new flare-up was a reemergence of a Liberian transmission chain originating from a persistently infected source rather than a reintroduction from a reservoir or a neighboring country with active transmission. Although distinct, Ebola virus (EBOV) genomes from both flare-ups exhibit significantly low genetic divergence, indicating a reduced rate of EBOV evolution during persistent infection. Using this rate of change as a signature, we identified two additional EVD clusters that possibly arose from persistently infected sources. These findings highlight the risk of EVD flare-ups even after an outbreak is declared over.

Keywords: Ebola virus; Ebola virus disease; Liberia; Western Africa; flare-up; persistent infection; reduced evolutionary rate; reemerged; transmission chain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Disease Outbreaks
  • Ebolavirus / genetics
  • Ebolavirus / pathogenicity*
  • Genome, Viral / genetics
  • Hemorrhagic Fever, Ebola / epidemiology*
  • Hemorrhagic Fever, Ebola / genetics
  • Hemorrhagic Fever, Ebola / transmission*
  • Hemorrhagic Fever, Ebola / virology
  • Humans
  • Liberia