Genetic Characterization of Enteroviruses Associated with Hand, Foot, and Mouth Disease in Yunnan Province, China, 2023

This study investigated the etiology of hand, foot and mouth disease (HFMD) in Yunnan Province, China, in 2023 by sequencing the complete VP1 region of enteroviruses. A total of 185 enteroviruses were identified from 429 stool samples collected from nine prefectures/cities in Yunnan Province in 2023. These findings revealed that CVA16 was the most prevalent serotype, followed by CVA4, CVA6, CVA10 and EV-A71. Phylogenetic analysis revealed that among the 76 CVA16 strains, 73 strains were subgenotype B1a, and 3 strains were B1b. Among the 32 CVA4 strains, 31 strains were subgenotype C2, and only 1 strain was C5. All 25 CVA6 strains belong to subgenotype D3a, all 22 CVA10 strains are genotype C, and all 11 EV-A71 strains are of the C4a subgenotype. HFMD genotypes and sub-genotypes are crucial for public surveillance and outbreak response, and can inform vaccine development.