Molecular epidemiological characteristics of coxsackievirus A6 in Jinhua, China, 2019–2023

We aimed to perform a retrospective analysis of the molecular epidemiological characteristics and genetic features of hand, foot and mouth disease (HFMD) associated with coxsackievirus A6 (CVA6) infections in Jinhua city from 2019 to 2023. Throat swab specimens were collected and tested. Two hundred CVA6-positive samples with viral loads>1 × [Formula: see text] copies/µL were randomly selected for VP1 sequence amplification and sequencing. Sequence analysis using sequencing analysis software. All methods were performed in accordance with the relevant guidelines and regulations. The number of HFMD cases fluctuated from 2019 to 2023.Children aged < 5 years accounted for the majority and boys were more frequently affected than girls. Genetic evolution analysis revealed that all 200 CVA6 strains belonged to subtype D3a and were on the D3a branch. Nucleotide homology and amino acid homology are somewhat different compared with representative strains in China and abroad. The full length of the CVA6 VP1 sequence was 915 bp, encoding 305 amino acids. Among the 200 prevalent strains in this study, 19 mutation sites were identified. Multiple transmission chains of CVA6 co-circulated in Jinhua City, exhibiting an enhanced virulence trend. There are multiple antigenic epitope amino acid variants in the VP1 gene.