Genetic analysis of the VP1 gene of enterovirus 71 in Ningbo

Objective To investigate the genetic characteristics of the VP1 gene of enterovirus 71(EV71) in Ningbo. Methods The clinical samples were collected from the patients with hand, foot and mouth disease, and EV71 was isolated and identified. The VP1 gene of EV71 isolates was amplified by reverse transcription-polymerase chain reaction and sequenced. The adaptive evolution of the VP1 gene of EV71isolates was analyzed, and the VP1 gene sequences of EV71 isolates were compared with each genotype representative strains. Meanwhile, the titers of isolates were determined. Results Out of twenty-three isolates, six EV71 strains were identified during 2008-2009. The VP1 gene evolution analysis showed that isolates in Ningbo were clustered with subgenotype C4 representative strain. The VP1 gene of six isolates shared the highest homology with subgenotype C4 both at nucleotide level(92.3%-93.1% ) and at amino acid level (98.9%-99.3%). The titers of six EV71 isolates ranged from 101.16 to 103.33 TCID50/ml. Conclusion EV71isolates in Ningbo belong to subgenotype C4. Key words: Enterovirus;  Genotype;  Sequence aligment