OBJECTIVETo study the variation and evolution rules and analyze the genetic characterization of echovirus 30 during an outbreak of aseptic meningitis.

METHODSFor all the echovirus 30 isolates during the outbreaks in Zhangqiu city in 2003, complete VP1 genes were determined. Phylogenetic tree reconstruction and pairwise sequence were determined to compare the homological relationship and evolution rules between Zhangqiu strains and the other reported echovirus 30 in GenBank.

RESULTSPairwise sequence comparisoms in VP1 region indicated that there were 98.9%-99.5% identity of nucleotide acid among Zhangqiu strains, and having the highest homology with Taian strains (98.5%-99.0%) isolated in Shandong province. At the same time, when comparing with Zhejiang and Jiangsu strains, the nucleotide homology showed 98.2%-98.9%, relatively low identity with Taiwan strains (87.4%-87.6%) and French strains (89.1%-89.7%) but only 82.4%-82.8% identity when comparing with echovirus 30 prototype strain Bastianni. Data from phylogenetic tree analyses indicated that all the echovirus 30 correlated with aseptic meningitis in China recently came from the same evolution linkage and formed a monophyletic cluster.

CONCLUSIONIn 2003, there was an circulation of echovirus 30 in Shandong province which causing an endemic of aseptic meningitis in local areas. Data from phylogenetic tree analyses indicated that the antigenic characteristics of echovirus 30 in mainland China might be different from strains early isolated in other continents and formed a new genotype.