Isolation, complete genome characterization and phylogenetic analysis of getah virus from a diseased pig herd in Hunan Province, China.

Getah virus (GETV) is a mosquito-borne alphavirus (family Togaviridae) that poses a significant threat to the swine industry by causing reproductive disorders in sows and neurological symptoms in piglets. In this study, a GETV strain, designated HN-2025, was isolated from a commercial pig farm in Hunan Province, China, during a clinical outbreak. The isolate induced typical cytopathic effects (CPE) in BHK-21 cells, including cell rounding, shrinkage, and detachment. The complete genome of HN-2025 was determined to be 11,689 nucleotides (nt) in length and exhibited the canonical genomic organization of GETV: 5' untranslated region (UTR), nonstructural proteins (nsP1-nsP4), structural proteins (C, E3, E2, 6 K, E1), and 3' UTR. Sequence homology analysis revealed that HN-2025 shared the highest nucleotide identity (98.6%-99.2%) with contemporary GIII genotype GETV strains circulating in Chinese pig herds. Phylogenetic analysis based on the complete genome and E2 gene sequences confirmed that HN-2025 clustered within the GIII genotype and was closely related to porcine GETV strains previously identified in central and southern China. These findings expand the molecular epidemiological understanding of GETV in Hunan Province and provide a valuable viral isolate for future studies on pathogenesis, diagnostics, and vaccine development.