Demographic history of the global circulation of segment B for vvIBDV and non-vvIBDV lineages using Bayesian skyline plot.

<p>The y axes of the skyline plots represent relative genetic diversity (Neτ) expressed as Log (Neτ). The x axis represents the number of years prior to the date of the most recent isolate in each lineage. The thick colored line is the mean estimate (red for vvIBDV lineage and blue for non-vvIBDV lineage), and the 95% HPD are indicated by the shaded area. Grey dashed lines frame the abrupt increase in Neτ for vvIBDV lineage, coinciding with the expansion of vvIBDV strains to Western Europe (Belgium) in 1987, Africa (Egypt) around 1990, East Asia (China and Japan) around 1993 and the Caribbean Region (Cuba) around 1991–1993 (see [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125853#pone.0125853.ref016" target="_blank">16</a>] for details).