Isolation, identification, and pathogenicity of a goose astrovirus 1 strain from goslings in Jiangsu province, China.

Goose astrovirus (GAstV) poses a large threat to the goose industry in China, with two genotypes: goose astrovirus genotype 1 (GAstV-1) and GAstV-2. GAstV-2 causes gout in goslings; however, understanding of GAstV-1 is limited. In this study, the GAstV-1 strain JY202323, was isolated from dead goslings, and its complete genome sequence was obtained using next-generation sequencing. Its whole genome was 7252 nucleotides in length, and its structure was similar to GAstV-1. Phylogenetic analysis revealed that GAstV-1 could be divided into two subgroups. Phylogenetic analysis of the complete genome and capsid protein sequences revealed that GAstV-1 could be divided into two subgroups. Infection of one-day-old goslings with JY202323 resulted in diarrhoea and weight loss with a mortality rate of approximately 13 %; however, typical gout symptoms were not observed, and no obvious tissue lesions were found upon autopsy. Immunohistochemical results showed that the GAstV-1 JY202323 strain could infect most tissues except the brain. Viral loads were high in the small intestine, duodenum, bursa of Fabricius, and lungs. Pathological analysis revealed significant lesions in the small intestine, lungs, bursa of Fabricius, and spleen; no lesions were observed in other tissues. Blood biochemical indicators were normal compared with the control group. GAstV-1 JY202323 mainly causes tissue damage in the small intestine and lungs as well as inflammatory responses in lymphoid tissues, which differ from GAstV-2. These findings provide new insights into GAstV-1 genetic diversity and pathogenicity, aiding in its prevention and control.