Genetic characterization of Echovirus 6 isolated from meningitis and encephalitis cases in Hebei province, China

Abstract

Objective To analyze the evolution and the genetic characteristics of echovirus 6 (ECHO6) isolated from encephalitis/ meningitis cases in Hebei province. Methods Cerebrospinal fluid (CSF) samples were collected from encephalitis/ meningitis patients at Children’s Hospital of Hebei province during 2013 to 2015. One hundred and fifty-seven CSF specimens, which were positive of human enterovirus confirmed by real-time PCR, were submitted to viral isolation. Viral RNA was extracted from the positive isolates, and the complete VP1 gene was amplified by PT-PCR and identified using BLAST research. Homology comparison and phylogenetic analysis of VP1 gene sequence were performed. Total of 175 reference sequences of ECHO6 viruses from nine provinces of China and other countries were downloaded from the GenBank database. Results Nineteen strains were identified as ECHO6 and these isolates belonged to genotype C and D9c. Homology analysis showed that the nucleotide identity was 79.3%-100% and amino acid identity was 95.8%-100% among 19 isolates. Compared with the prototype strain (D’Amori), the nucleotide identity and amino acid identity were 76.2%-78.3% and 92.3%-95.1% respectively. Conclusions Genotype C and D9c were the predominant genotypes of ECHO6 causing encephalitis/ meningitis in children in Hebei province during 2013-2015. Key words: Children; Encephalitis/meningitis; Echovirus 6; Genetic characteristics