[Study on the etiological and molecular characteristics of aseptic meningitis epidemic in Zhejiang Province in 2002-2004].

In order to confirm the cause of the outbreak of aseptic meningitis in Zhejiang Province in 2002-2004, trace the pathogen and analyze the molecular characteristics, 271 cerebrospinal fluid (CSF) and faeces specimens were collected from suspected patients. The virus strains from the specimens were isolated with RD and Hep-2 cell lines. The VP1 and VP4/VP2 genes of the isolated viruses were sequenced, and their phylogenetic and homology trees were also constructed. Of the total 271 samples, 78 Echovirus type 30 (E30) strains were isolated. All of the complete VP1 genes in 31 sequenced virus isolates of E30 were composed of 876 nt without any insertion or deletion, encoding 292 amino acids (aa). The identity of nucleotide and amino acid in VP1 gene were 84.7%-86.3% and 92.1%-94.2% between the 31 Zhejiang strains and the prototype strain Bastianni of E30, and 87.1%-99.4% and 96.2%-100% among the 31 Zhejiang strains, respectively. The Zhejiang strains of E30 in the phylogenetic tree of the VP1 gene were attributed into two branches of the G and H genotype, respectively. In G genotype, the Shangdong and Jiangsu E30 strains in 2003 among domestic strains and Ukraine E30 strain in 1999 among overseas strains had maximum similarity with the Zhejiang strains, while H genotype had maximum similarity with the Korea E30 strains in 2008. The phylogenetic tree of the VP4/VP2 genes was similar to that of VP1 gene. The results indicated that the outbreak of aseptic meningitis in Zhejiang Provinec in 2002-2004 was caused by the G and H genotypes of E30 strains existing simultaneously. The H genotype was a new variant strain, which was first isolated in Zhejiang Province in 2002.