Molecular Epidemiology of Coxsackievirus A10 Associated With Hand, Foot and Mouth Disease From 2021 to 2024 in Shenzhen, China

The study aimed to investigate epidemiological profile and molecular characteristics of coxsackievirus A10 (CVA10) associated with hand, foot and mouth disease (HFMD) in Shenzhen, China and comparatively analyze genomes of CVA10 strains related to differential clinical phenotypes. A total of 3170 clinical specimens collected between 2021 and 2024 were examined for CVA10 using real-time RT-PCR. Complete VP1 sequences and near-complete genome sequences of CVA10 were determined by RT-PCR methods and sequencing. Sequences were analyzed using a series of bioinformatics programs. Two (33.33%) out of 6 severe cases were infected with CVA10. The detection rate of CVA10 associated with mild HFMD ranged from 1.21% to 6.11% in 2021-2024, with an overall detection rate of 3.73%. There was no significant difference in the infection rate of CVA10 between males and females or different age groups. The CVA10 infections mainly occurred in Spring (March to May) and Summer (June to August) in Shenzhen. Of the 74 VP1 sequences determined, 71 (95.95%) of them were detected in the sub-genotype C2, 3 (4.05%) were assigned to the genotype D. Genomic sequence analysis indicated that the genotype D of CVA10 of this study derived from genetic recombination between CVA10 and CVA16 in 3A-3D coding region (nucleotide position: 5075-6896). Different variable sites were observed in the two CVA10 strains associated with different severe complications when compared to CVA10 strains associated with mild diseases. In conclusion, CVA10 associated with HFMD circulated at a low level in Shenzhen in 2021-2024, with C2 as the predominant genotype. Recombinant genotype D of CVA10 was introduced first to Shenzhen in 2024. The study emphasizes the importance of continuous molecular surveillance of CVA10.