Isolation and Molecular Characterization of Emerging Getah Virus Genotype III Variant Strains from Swine in...

As a member of the Alphavirus genus, Getah virus (GETV) has become an emerging pathogen posing severe threats to animal health and public health security. In recent years, GETV has caused increasing outbreaks in swine herds, leading to substantial economic losses in the pig industry in China. Here, we report continuous GETV outbreaks on pig farms across southeastern China between September 2024 and December 2025. A total of 185 clinical samples were examined, among which 27 were positive (14.6%). Subsequently, five GETV strains were successfully isolated and subjected to whole-genome sequencing. Phylogenetic analysis revealed that all the 5 isolated strains belonged to genotype III(GIII), with two strains (GETV-AHX2024 and GETV-JS2024) forming a distinct GIII variant clade. Notably, multiple specific amino acid mutations were identified in the nsp3, C, E2, 6K, and E1 proteins and 3'UTR of these GIII variant strains. Pathogenicity in mice revealed that mice infected with the GIII variant strain GETV-JS2024 exhibited a longer viral shedding period compared with other strains. These findings highlight the emergence of GETV GIII variant strains in southeastern China and suggest their altered pathogenic performance in mice. These results supplied critical data for molecular surveillance and subsequent pathogenic analysis of GETV in China.