RT Journal Article
SR Electronic
T1 Evolutionary stasis of an RNA virus indicates arbovirus re-emergence triggered by accidental release
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2019.12.11.872705
DO 10.1101/2019.12.11.872705
A1 David J Pascall
A1 Kyriaki Nomikou
A1 Emmanuel Bréard
A1 Stephan Zientara
A1 Ana da Silva Filipe
A1 Bernd Hoffmann
A1 Maude Jacquot
A1 Joshua B. Singer
A1 Kris De Clercq
A1 Anette Bøtner
A1 Corinne Sailleau
A1 Cyrille Viarouge
A1 Carrie Batten
A1 Giantonella Puggioni
A1 Ciriaco Ligios
A1 Giovanni Savini
A1 Piet A. van Rijn
A1 Peter PC Mertens
A1 Roman Biek
A1 Massimo Palmarini
YR 2019
UL http://biorxiv.org/content/early/2019/12/13/2019.12.11.872705.abstract
AB The mechanisms underlying virus emergence are rarely well understood, making the appearance of outbreaks largely unpredictable. Bluetongue virus serotype 8 (BTV-8), an insect-borne virus of ruminants, emerged in livestock in Northern Europe in 2006, spreading to most European countries by 2009 and causing losses of billions of Euros. Though the outbreak was successfully controlled through vaccination by early 2010, puzzlingly a closely-related BTV-8 strain re-emerged in France in 2015, triggering a second outbreak that is still ongoing. The origin of this virus and the mechanisms underlying its re-emergence are unknown. Here, we performed phylogenetic analyses of 164 whole BTV-8 genomes sampled throughout the two outbreaks. We demonstrate consistent clock-like virus evolution during both epizootics but found negligible evolutionary change between them. We estimate that the ancestor of the second outbreak dates from the height of the first outbreak in 2008. This implies that the virus had not been replicating for multiple years prior to its re-emergence in 2015. Given the absence of any known natural mechanism that could explain BTV-8 persistence over this period without replication, we conclude that the second outbreak was most likely initiated by accidental exposure of livestock to frozen material contaminated with virus from approximately 2008. Our work highlights new targets for pathogen surveillance programmes in livestock and illustrates the power of genomic epidemiology to identify pathways of infectious disease emergence.