Reclassification and Recombination Analysis of Porcine Epidemic Diarrhea Virus Strains in South Korea Based on Spike Gene Analysis

Porcine epidemic diarrhea (PED) is a severe and highly contagious enteric disease of pigs caused by porcine epidemic diarrhea virus (PEDV). The spike (S) protein of PEDV is the main driving force for viral entry into host cells, influencing the pathogenicity and virulence of the virus subgroup. Currently, the S gene of PEDV exhibits a wide array of variations, with numerous mutations reported. Consequently, recent studies on the phylogenetic classification of PEDV have categorized these variants into clusters or lineages. In this study, 161 PEDV subgroups, including 58 Korean isolates and 103 global PEDV reference subgroups, were classified into two groups, G1 and G2, with nine subgroups (G1a, G1b, G1c, G1d, G2a, G2b, G2c, G2d, and G2e) based on the complete S gene. Phylogenetic analysis revealed that the subgroups isolated in Korea between 2021 and 2022, which were previously reported as G2b subgroups, were G2e subgroups, derived as potential recombinants from the G2a and G1d subgroups. These results indicate that PEDV subgroups isolated from Korea may require reclassification based on recently reported subgroups.