It is possible that different lineages are indeed maintained in a large area with occasional movement of viral lineages between continents, while within each area, e.g. east Asia, transmissions between borders may be still common [13].Evolutionary rate estimationOur estimated rates of change for synonymous sites of 2A and 3C were close to that of the poliovirus (3.96 ?? 10-2/site/year) [31], but h