OBJECTIVETo investigate the pathogen spectrum constitution of HEV related to acute meningitis/encephalitis syndrome (AMES) and to analyze the genetic characterization of the echovirus 30 (Echo30) isolates.

METHODSCerebrospinal fluid, stool, and/or throat swab specimens from 101 AMES cases were collected for virus isolation with RD and HEp-2 cell lines in Linyi city from April to December, 2010. After typing by neutralization test, the entire VP1 gene of the isolates were amplified by RT-PCR and sequenced. Homologous comparison was carried out and phylogenetic analysis were performed.

RESULTSHEVs were isolated from 47 specimens of 34 patients (4 from cerebrospinal fluid, 18 from throut swab and 25 from stool), with 11 Echo30 isolates identified by microneutralization assay and molecular typing method. In alignment of VP1 sequences with global Echo30 isolates, relative high nucleotide homologies (91.2% - 95.4%) with Taian, Zhangqiu and Jiangsu isolates and high divergences (17.9% -19.6%) with prototype strain were observed. Nucleotide divergences among Linyi isolates were 0 - 10.2%, and 3 lineages were revealed via phylogenetic analysis, reflecting 3 transmission chains of Echo30 co-circulated in Linyi city, 2010.

CONCLUSIONEcho30 was the predominant serotype of AMES cases in Linyi city, 2010. These isolates possessed considerable divergence with Echo30 from other countries.