Objective To understand pathogen spectra of hand foot and mouth disease (HFMD) and herpangina in Xuzhou, Jiangsu province, and analyze the VP1 gene characteristics of coxsackievirus A6 (Cox A6), coxsackievirus A4 (Cox A4), and coxsackievirus A10 (Cox A10).
Methods Real-time polymerase chain reaction (PCR) and nested PCR amplifications were used to detect the enterovirus serotypes in HFMD and herpangina case samples. Human rhabdomyosarcoma cells were used to isolate the virus strains from positive samples. The gene sequence analysis of the VP1 region were implemented. The phylogenetic tree was constructed according to the entire gene sequence on VP1 region, and the homology analysis was performed.
Results In 2021, the top four predominant serotypes of coxsackievirus causing HFMD were Cox A6, Cox A16, Cox A10 and Cox A4, and the top four predominant serotypes of coxsackievirus causing herpangina were Cox A4, Cox A10, Cox A2 and Cox A6 in Xuzhou. The phylogenetic tree constructed based on the VP1 region gene shows that Cox A6, Cox A10, and Cox A4 strains belonged to subtype D3a, C2, and C2, respectively, which had close relationship with reference strains isolated in China in recent years. There was no significant difference in the VP1 region genes between virus strains of two viruses.
Conclusion The pathogen spectra of HFMD and herpangina were not completely consistent in Xuzhou. Cox A10 and Cox A4, co-circulating with Cox A6 and Cox A16, were serotypes causing HFMD and herpangina. Continuous surveillance for HFMD and herpangina pathogen spectra and genetic variations should be carried out to prevent outbreaks of HFMD and herpangina.