FDJS03 isolates causing an outbreak of aseptic meningitis in China that evolved from a distinct Echovirus 30 lineage imported from countries of the Commonwealth of Independent States.

We compared echovirus 30 strains (FDJS03) which caused an outbreak of aseptic meningitis in China in 2003 with other human enterovirus B strains. Sequencing of the complete genome of FDJS03_84, a representative strain from this outbreak, revealed a mosaic structure with a putative recombination spot within the 2B gene. It was most similar to a strain of the same serotype, E30-14125-00, in the 5' half of the genome but was almost equidistant to all strains analyzed in most of the 3' half of the genome. Phylogenetic relationships in the 5'-untranslated region and the VP1 gene indicated that the FDJS03 isolates were closely related to a distinct lineage of E30 which circulated in countries of the Commonwealth of Independent States during 1999 and 2000. It is most likely that the ancestor of FDJS03 isolates experienced multiple recombination events in the nonstructural protein coding region, which were partly observed in the phylogenetic analysis of the 3D region.