Detection and Characterization of Goose Astrovirus Infections in Hatcheries and Commercial Goose Flocks

Goose astrovirus (GoAstV) has frequently been isolated in China since it was first identified as the etiological agent of visceral gout in goslings in 2017. However, the actual prevalence of GoAstV infection and its economic impact on commercial goose production remain poorly characterized. Here, virus detection and serological testing were conducted to determine the extent of GoAstV infection in commercial goose flocks. We detected GoAstV RNA in 2% (6/300) of dead-in-shell embryos and day-old hatched goslings by RT-PCR, indicating vertical transmission under natural conditions. Using a virus neutralization test, GoAstV antibodies were detected in 41.7%-61.1% of serum samples from four commercial goose flocks, indicating that infections were common. To determine the virus types circulating in the commercial flocks, we isolated 15 GoAstVs from goose tissue samples from farms located in five provinces during 2018-2022. Genomic sequence analysis showed that all sequences were corresponded to GoAstV group 2 (GoAstV-2) but were assigned into three capsid subgroups based on sequence variations in the capsid protein. Representative isolates of capsid subgroups were also antigenically evaluated using cross-neutralization tests in LMH cell cultures. The antigenic relatedness values (R) calculated using the Horsfall formula were between 62% and 86%, indicating that no significant antigenic differences exist between the isolates. Our findings indicate that GoAstV-2 viruses are an important cause of fatal gout in goose flocks, as well as hatchery contamination in China.