Complete genome characterization, phylogenetic analysis, and capsid P2 variation of a goose astrovirus genotype 2 isolate from Guizhou, China.

Goose astrovirus genotype 2 (GAstV-2) is associated with gout and renal disease in goslings, but its occurrence in Guizhou Province remains poorly documented. We isolated a GAstV-2 strain, designated GZJP2024, from goslings with visceral gout on a farm in Jinping County, Guizhou Province, China. PCR detected GAstV-2 but not goose parvovirus, goose reovirus, Tembusu virus, fowl adenovirus, or goose astrovirus genotype 1. Serial passage in goose embryos produced mortality and hemorrhagic lesions during the third passage. Whole-genome sequencing yielded a 7,251-nt genome containing three overlapping open reading frames (ORF1a, ORF1b, and ORF2). Sequence identity and phylogenetic analyses assigned GZJP2024 to the GAstV-2 lineage. ORF1b was the most conserved coding region, whereas ORF2 was more variable. Comparison with consensus sequences from representative GAstV-2 strains identified five amino acid substitutions in ORF1a and ten in ORF2. Four ORF2 substitutions (E456D, L540Q, S608T, and A614T) occurred in the capsid P2 domain and overlapped or neighbored predicted B-cell epitope-rich regions. Template-based mapping placed E456D, S608T, and A614T on exposed regions of a spike-like capsid structure. These findings document a GAstV-2 isolate from a gout-affected goose farm in Guizhou and provide sequence data for future regional surveillance.