Reduced evolutionary rate in reemerged Ebola virus transmission chains

Blackley DJ, Michael R. Wiley, Jason T. Ladner, Mosoka Fallah, Terrence Lo, Merle L. Gilbert, Christopher Gregory, Jonathan D?ambrozio, Stewart Coulter, Suzanne Mate, Zephaniah Balogun, Jeffrey Kugelman, William Nwachukwu, Karla Prieto, Adolphus Yeiah, Fred Amegashie, Brian Kearney, Meagan Wisniewski, John Saindon, Gary Schroth, Lawrence Fakoli, Joseph W. Diclaro II, Jens H. Kuhn, Lisa E. Hensley, Peter B. Jahrling, Ute Ströher, Stuart T. Nichol, Moses Massaquoi, Francis Kateh, Peter Clement, Alex Gasasira, Fatorma Bolay, Stephan S. Monroe, Rambaut A, Mariano Sanchez-Lockhart, A. Scott Laney, Tolbert Nyenswah, Athalia Christie & Palacios G

(2016) Science Advances 2, e1600378.

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.

Andrew Rambaut, 2007