Analysis of the pathogen spectrum of severe hand, foot and mouth disease and genetic characteristics of enterovirus A71 in Xianyang, 2018 / 中华实验和临床病毒学杂志

ABSTRACT

Objective@#To understand the pathogen spectrum of severe hand, foot and mouth disease (HFMD), and analyze the genetic characteristics of enterovirus A71(EV-A71) in Xianyang in 2018.@*Methods@#Totally 67 specimens of severe cases of HFMD were collected. Enteroviruses associated with HFMD were detected by real-time PCR and the genotypes of enteroviruses were identified by VP4 region of enteroviruses. The nucleotide and amino acid sequences of VP1 region of EV-A71 were analyzed.@*Results@#A total of 30 samples were positive for enterovirus among samples from 67 severe cases with HFMD, including 9 cases of EV-A71, 11 cases of coxsackievirus A6 (CV-A6), 5 cases of coxsackievirus A16 (CV-A16), 2 cases of coxsackievirus A10 (CV-A10) and 2 cases of coxsackievirus A4 (CV-A4). The nucleotide and amino acid homologies of EV-A71 among 4 strains reached 96.7%-99.9% and 99.3%-100% respectively. The 4 strains of EV-A71 belonged to C4a subtypes by phylogenetic analysis. The six amino acid composite model was KADSTV in 4 strains of EV-A71. The EF region and GH region in antigenic determinants of 4 strains of EV-A71 kept consistent with representative reference strains, however, the EV-A71 SZK222 and SZK497 strains developed mutation at site 93 (I93V) of BC loop region.@*Conclusions@#EV-A71 and CV-A6 are major agents of severe HFMD in Xianyang in 2018. The genotype of EV-A71 belonged to C4a subtype and the VP1 gene did not show more mutations.