Genomic characterization, recombination analysis and pathogenicity of goose astrovirus 2 isolated from geese in Jiangxi Province, China.

Goose astrovirus genotype 2 (GoAstV-2) has emerged as an important pathogen of goslings in China since 2016, causing severe gout-like disease with renal damage and growth retardation. However, the genetic relationships, potential recombination events, and pathogenic properties of GoAstV-2 strains circulating in Jiangxi Province remain incompletely characterized. In this study, clinical samples were collected from diseased goslings at local goose farms in Jiangxi Province. Three GoAstV-2 strains, designated JX06, JX07, and JX08, were isolated from samples collected in May, July, and October 2025. Complete-genome sequencing and phylogenetic analysis placed all three isolates within the GoAstV-2 lineage and showed close relatedness to representative GoAstV-2 strains. Recombination analysis predicted JX08 as a recombinant strain with breakpoints at nucleotides 4882 and 6296, and identified JX06 and JX07 as its closest putative parental strains. Notably, the recombinant region was located within ORF2, which encodes the viral capsid protein. Subsequent in vitro and in vivo analyses showed that JX08 was capable of replication in LMH cells and caused GoAstV-2-associated disease manifestations in experimentally infected one-day-old goslings, including growth retardation, an increased kidney index, elevation of serum uric acid, gross and histopathological lesions, and detectable viral RNA copies in multiple tissues. In summary, these findings provide new genomic information on GoAstV-2 strains circulating in Jiangxi Province and experimental pathogenicity data for JX08, highlighting the importance of continued genomic surveillance in goose production systems.