Abstract
BackgroundEnterovirus 71 (EV71) is the most commonly implicated causative agent of severe outbreaks of paediatric hand, foot, and mouth disease (HFMD).VP1 protein, a capsid protein of EV71, is responsible for the genotype of the virus and is essential for vaccine development and effectiveness. However, the genotypes of EV71 isolates in China are still not completely clear.MethodsThe VP1 gene sequences of 3712 EV71 virus strains from China, excluding repetitive sequences and 30 known EV71 genotypes as reference strains, between 1986 and 2019 were obtained from GenBank. Phylogenetic tree, amino acid homology, genetic variation and genotype analyses of the EV71VP1 protein were performed with MEGA 6.0 software.ResultsThe amino acid identity was found to be 88.33%–100% among the 3712 EV71 strains, 93.47%–100% compared with vaccine strain H07, and 93.04%–100% compared with vaccine strains FY7VP5 or FY-23 K-B. Since 2000, the prevalent strains of EV71 were mainly of the C4 genotype. Among these, the C4a subgenotype was predominant, followed by the C4b subgenotype; other subgenotypes appeared sporadically between 2005 and 2018 in mainland China. The B4 genotype was the main genotype in Taiwan, and the epidemic strains were constantly changing. Some amino acid variations in VP1 of EV71 occurred with high frequencies, including A289T (20.99%), H22Q (16.49%), A293S (15.95%), S283T (15.11%), V249I (7.76%), N31D (7.25%), and E98K (6.65%).ConclusionThe C4 genotype of EV71 in China matches the vaccine and should effectively control EV71. However, the efficacy of the vaccine is partially affected by the continuous change in epidemic strains in Taiwan. These results suggest that the genetic characteristics of the EV71-VP1 region should be continuously monitored, which is critical for epidemic control and vaccine design to prevent EV71 infection in children.
Highlights
Enterovirus 71 (EV71) is a common pathogen of hand, foot, and mouth disease (HFMD) in children, and it is the most important risk factor for severe cases and deaths [1,2,3,4].Some children with HFMD can have severe neurological effects, such as aseptic meningitis, encephalitis and acute delayed paralysis, develop seriousEV71 was first discovered in 1969; the virus was distributed mainly in the Americas, Europe and other countries in a sporadic form, with outbreaks in some European countries in the 1970s and 1980s [9, 10]
Phylogeny and homology analysis of the EV71 VP1 region A phylogenetic tree of the VP1 amino acid sequence was constructed with 3712 EV71 isolates from China and 30 reference strains (Fig. 3)
Genotypic distribution of EV71 strains in different years in China Among the 3712 strains, the first 6 strains isolated from China in 1986were all of the B3 genotype, after which different genotypes/subgenotypes were detected in China
Summary
Enterovirus 71 (EV71) is a common pathogen of hand, foot, and mouth disease (HFMD) in children, and it is the most important risk factor for severe cases and deaths [1,2,3,4].Some children with HFMD can have severe neurological effects, such as aseptic meningitis, encephalitis and acute delayed paralysis, develop seriousEV71 was first discovered in 1969; the virus was distributed mainly in the Americas, Europe and other countries in a sporadic form, with outbreaks in some European countries in the 1970s and 1980s [9, 10]. Enterovirus 71 (EV71) is a common pathogen of hand, foot, and mouth disease (HFMD) in children, and it is the most important risk factor for severe cases and deaths [1,2,3,4].Some children with HFMD can have severe neurological effects, such as aseptic meningitis, encephalitis and acute delayed paralysis, develop serious. Sun et al Gut Pathog (2020) 12:38 caused by EV71 infection have been widely prevalent in China since 2007 [13]. Phase III clinical trials of vaccines from three companies in China have been completed, and the genotypes of their vaccine strains are all C4a subgenotypes [26]. Enterovirus 71 (EV71) is the most commonly implicated causative agent of severe outbreaks of paediatric hand, foot, and mouth disease (HFMD).VP1 protein, a capsid protein of EV71, is responsible for the genotype of the virus and is essential for vaccine development and effectiveness. The genotypes of EV71 isolates in China are still not completely clear
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