Study on virulence related sites based on human enterovirus A71 genome

Objective To explore the virulence related risk factors based on the enterovirus A71 (EV-A71) genome. Methods The pairwise distance of each section of gene between mild and fatal cases was analyzed. The ⅴ domain of 5′UTR from mild and fatal cases in this study were constructed. Amino acid sequences of EV-A71 were analyzed to find the potential virulence regions which were statistically different between fatal and mild cases. Results The two EV-A71 genome sequences in this study belonged to C4a genotype with the genomic homology of 96.2%-97.5%. The nucleotides in the ⅴ domains of the 5 ′UTR of EV-A71 from mild and fatal cases were the same. Each gene of EV-A71 from 31 mild cases and 30 fatal cases shared high homology. A total of four potential virulence sites (2 A: R68 M、2C: K41R、3 A: T/V47 A and 3C: I158 V) which were significantly different between mild cases and fatal cases were obtained. Conclusions The four sites in the unstructured protein coding region might be related with the virulence of EV-A71. Key words: Enterovirus A71; Genome; Virulence