Molecular detection and identification of goose astrovirus in GuangDong Province, China

In recent years, Goose Astrovirus (GAstV) has become a major pathogen in China, afflicting geese with significant clinical manifestations like gout and urate deposits in organs. Notably, similar symptoms have emerged in ducks. From 2023 to 2024, 126 liver samples were collected from ducks in Guangdong Province, where farms reported emaciation, paralysis, and deaths. Metagenomic analysis pinpointed GAstV as the primary pathogen, with a 43.65 % confirmed positive rate via qPCR. A new strain, GD2406, was identified, showing 97.5 %-98.8 % similarity to 30 GAstV-2 strains in GenBank. GD2406 displayed 98.3 % and 97.7 % identity with the duck strains HNNY0620 and SDTA, and 98.3 % and 98.4 % identity with highly virulent GAstV strains HNKF-1 and HNSQ-6. Phylogenetic analysis indicated a genetic closeness between GD2406 and the goose strain HB01. There were 13 amino acid mutations, mainly within ORF2, and a single mutation differing from HNKF-1 and HNSQ-6, hinting at significant pathogenic potential for both ducks and geese. This study is the first to report GAstV causing severe symptoms and mortality in Muscovy ducks in Guangdong Province, suggesting ducks could be key hosts and underscoring the risk of cross-species transmission.