Study on the genetic characterization and molecular epidemiology of echovirus 11 strains isolated in Shandong province, China / 中华流行病学杂志

ABSTRACT

Objective To analyze the evolution and genetic characterization of echovirus 11 (Echo11 ) from the acute flaccid paralysis (AFP) cases in Shandong province. Methods Isolation of Enterovirus was performed from stool samples of AFP cases from 1994 to 2009. All positive strains were sero-typed by neutralization test. Entire VP1 coding region from 27 strains typed as Echo 11 was amplified by reverse transcription-polymerase chain reaction(RT-PCR), and subsequently phylogenetic analyse on VP1 sequences from these strains and others published in GenBank were conducted. Results From 1994 to 2009, altogether 915 non-polio enterovirus (NPEV) strains were isolated with 79(8.6% ) isolates serotyped as Echo11. There were 876 nucleotides (nt) in the complete VP1 genes, encoding 292 amino acids (aa). The nt identities were 76.4%-100.0% among those Echo11 Shandong strains with the aa identities as 91.4% -100.0%. The nt and aa identities were 77.7%-80.7% and 90.7%-94.8% between Shandong strains and prototype strains, respectively.Conclusion All Echo11 strains could be divided into four genotypes. Shandong strains that forming three (A1, A2 and C1) new sub-genotypes, with every sub-genotype had several brands.Sub-genotype A1 appeared to be the lately circulating one.