Objective: Genetic evolution of VP1 of enterovirus type 71 in Shenzhen were analyzed.
Methods: All samples were tested by RT-PCR using EV71 specific primer. The VP1 of EV71 were amplified and sequenced. A phylogenetic tree was constructed by comparison of the sequences with subgenotype A, B and C using DNAStar, BioEdit and Mega 3.1 software.
Results: Among 35 strains, the homogeneity of the VP1 nucleotide sequence was between 92.1%-100%. The homogeneity of the VP1 nucleotide sequence with subgenotype A and B was between 81.4% -91.1%. The VP1 nucleotide sequence of 35 strains of Shenzhen shared between 93% -97.4% identity with cluster C4. The prevalence strains of EV71 were cluster C4b from 1998 to 2004, and gradually moved to C4a since 2003. All of EV71 were C4b from 2006 to 2008. Also, the homogeneity of the VP1 nucleotide sequence with Anhui FY23 EV71 strain were 94.5% -94.7%, 95.7% -95.8%, 96.2%, 95.4% -97.5%, 96.3% -99.2% from 2003 to 2008. It shows that the homogeneity was increased year by year. There was a mutation (A --> C) at No. 66 nucleotide of VP1 of EV71 that two strains were isolated in 2003 and 8 strains in 2008, that caused amino acid mutation (Q --> H) at No. 22 of VP1.
Conclusion: EV71 C4b was gradually moved to C4a from 1998 to 2008. There was a missense mutation at No. 66 nucleotide of VP1.