Genetic characteristics of echovirus type 25 strains causing viral encephalitis in Longyan city / 中华微生物学和免疫学杂志

ABSTRACT

Objective To analyze the genetic characteristics of echovirus type 25( Echo25) strains isolated from patients with viral encephalitis in Longyan city. Methods Cerebrospinal fluid(CSF) specimens were collected from hospitalized patients with viral encephalitis or central nervous system infection in Longyan,2012. Enteroviruses(EV)were isolated from the specimens and then identified. Four strains of Echo25 were screened out by using serum neutralization test. Coding sequence of the VP1 region of the 4 Echo25 strains were amplified by RT-PCR and then sequenced. A phylogenetic tree was constructed to ana-lyze the nucleotide sequence homology between those sequences and the sequences of reference Echo25 strains available in the GenBank database. Results The VP1 nucleotide sequences of Echo25 strains isola-ted in Longyan were 498 bp in length,encoding 166 amino acid residues. The homology analysis showed that the VP1 nucleotide sequences of 3 strains were identical,sharing 97% homology in nucleotide with the rest strain. The Echo25 strains isolated in Longyan were highly similar to KJ957190( Beijing,2010)and HM031189(Henan,2008)strains. Phylogenetic analysis revealed that the Echo25 strains isolated in Longyan belonged to genotype B1. Conclusion Echo25 was one of the pathogens causing viral encephalitis in Longyan in 2012 and different transmission chains of Echo25 had emerged. This study indicates that it is necessary to strengthen the surveillance for EV and understand the genetic variation of the Echo25 for provi-ding better supportive evidences for the prevention and control of related diseases.