Epidemiology of hand, foot and mouth disease and genomic surveillance of coxsackievirus A10 circulating in Zhejiang Province, China during 2017 to 2022

BACKGROUND: Coxsackievirus A10 (CA10) is one of the etiological agents associated with hand, foot and mouth disease (HFMD). OBJECTIVES: We aimed to perform a retrospective analysis of the molecular epidemiological characteristics and genetic features of HFMD associated with CA10 infections in Zhejiang Province from 2017 to 2022. STUDY DESIGN: Epidemiologic features were summarized. Throat swab specimens were collected and tested. The VP1 regions were sequenced for genotyping. CA10 positive samples were isolated. Whole genomes of CA10 isolations were sequenced. Nucleotide and amino acid changes were characterized. Phylogenetic trees were constructed. RESULTS: The number of HFMD cases fluctuated from 2017 to 2022. Children aged below 3 years accounted for the majority (66.29%) and boys were more frequently affected than girls. Cases peaked in June. The positivity rate of HEV was 62.69%. A total of 90 strains of CA10 were isolated and 53 genomes were obtained. All CA10 in this study could be assigned to two genogroups, C (C2) and F (F1 and F3). CONCLUSION: The clinical manifestations of HFMD associated with HEV are complex and diverse. CA10 infection may be emerging as a new and major cause of HFMD because an upward trend was observed in the proportion of CA10 cases after the use of EV71 vaccines. Different genogroups of CA10 had different geographic distribution patterns. Surveillance should be strengthened and further comprehensive studies should be continued to provide a scientific basis for HFMD prevention and control.