Abstract:[Background] Since 2016, gout caused by goose astrovirus (GAstV) infection in goslings has spread extensively among goose farms throughout China. [Objective] To investigate the pathogenicity of two endemic GAstV strains isolated and identified, thereby providing foundational data for further research on GAstV. [Methods] Two tissue samples, tested positive for goose astrovirus type 1 (GAstV-1) and goose astrovirus type 2 (GAstV-2) via PCR, were selected for further analysis. Goose embryos were used for virus isolation. Following sequencing verification, the whole genome sequences of the two GAstV strains were amplified. The pathogenicity of the two isolated GAstV strains was evaluated by an animal regression test. The clinical symptoms, pathological manifestations during necropsy, and histopathological changes of goslings were observed after intramuscular injection of GAstV suspensions. [Results] In this study, one isolate each of GAstV-1 and GAstV-2 were successfully obtained and named GDYJ-21-01 (GenBank: OP776630) and GDZJ-21-01 (GenBank: OP776629), respectively. Whole genome sequence alignment results indicated that GDYJ-21-01 clustered within the GAstV-1 branch and shared 89.70% to 98.60% similarity with GAstV-1. GDZJ-21-01, on the other hand, was situated within the GAstV-2 branch and shared 97.10% to 99.30% similarity with GAstV-2. After GAstV infection, goslings showed signs of emaciation. Necropsy of deceased goslings revealed urate deposits in their organs. Histopathological examinations demonstrated small focal necrosis of myocardial fibers, congestion and dilation of hepatic sinusoids in the liver, splenic congestion, as well as disruption of the original structure of some renal tubules, renal tubule dilation, and mild hyperplasia of the interstitial connective tissue in the kidney tissue. [Conclusion] We successfully isolated the GAstV-1 strain GDYJ-21-01 and the GAstV-2 strain GDZJ-21-01. Both strains were proven capable of infecting goslings and inducing gout.
