Evolutionary dynamics of lineage 2 West Nile virus in Europe, 2004-2018: Phylogeny, selection pressure and phylogeography

Publication date: Available online 12 September 2019Source: Molecular Phylogenetics and EvolutionAuthor(s): Serafeim C. Chaintoutis, Anna Papa, Danai Pervanidou, Chrysostomos I. DovasAbstractWest Nile virus (WNV) is an arbovirus causing neuroinvasive disease to humans and equines. Since 2004, lineage 2 WNV strains have been identified in Europe and have been implicated in severe outbreaks, with that of 2018 exceeding the total number from the previous seven years. The aim of this study was to explore the evolutionary process that shapes the genetic diversity of lineage 2 WNV strains (belonging to the Central European/Hungarian subclade) and reconstruct the origin and transmission routes in Europe, and especially in the Balkans. For this purpose, a high number of whole genome sequences (WGSs) were analyzed, along with newly characterized sequences, including strains from the 2018 WNV transmission season in Greece. Maximum likelihood and Bayesian inference methods were used to perform the phylogenetic and phylodynamic analyses and phylogeographic reconstruction. The majority of the Central European/Hungarian lineage 2 strains are grouped in 2 phylogenetic subgroups (Central/South-West European and Balkan) with bush-like topology. Purifying selection shapes their evolution, however, strong evidence of positive selection was revealed in seven non-structural protein codons of NS1, NS4B, and NS5. Thirty-two amino-acid substitutions were fixed in different phylogenetic subgroups, in...
Source: Molecular Phylogenetics and Evolution - Category: Molecular Biology Source Type: research