Genetic characterization of EV71 isolates associated with hand, foot and mouth disease in the mainland of China / 中华临床感染病杂志

ABSTRACT

Objective:To analyse the genetic characteristics of VP1 region and genotypes of enterovirus 71 (EV71) associated with hand, foot and mouth disease (HFMD) in the mainland of China.Methods:The VP1 gene sequences of 3 102 isolates of EV71 from the mainland of China(excluding repetitive sequences)and 30 known EV71 genotypes as reference strains between 1996 and 2018 were obtained from GenBank. Phylogenetic tree, amino acid homology, genetic variation and genotype analyses of the EV71-VP1 protein were performed with MEGA 6.0 software.Results:The amino acid identity was 88.33%-100.00% among the 3 102 EV71 strains, if included reference strains it was 87.34%-100.00%. The amino acid identity was 93.47%-100.00%, compared with vaccine strain H07, and 93.04%-100.00% compared with vaccine strains FY7VP5 or FY-23K-B. Since 2000, the prevalent strains of EV71 were mainly of the C4 genotype; while during 2005 to 2018 the C4a subgenotype was predominant, followed by the C4b, other subgenotypes appeared sporadically. Some amino acid variations in VP1 of EV71 occurred with high frequencies, including A293S (16.75%), S283T (15.73%), A289T (12.44%), E98K (7.22%), H22Q (6.66%), N31D (4.50%) and V249I (4.40%).Conclusion:The C4 genotype of EV71 in China’s mainland matches the vaccine and should effectively control EV71 infection. Genetic characteristics of the EV71-VP1 region should be continuously monitored, which is critical for epidemic control and vaccine design to prevent EV71-HFMD in children.