Isolation, identification, and pathogenicity analysis of newly emerging gosling astrovirus in South China

Abstract

Goose astroviruses (GoAstV) cause fatal gout and decrease product performance in the waterfowl industry across the world. Since no effective vaccines are available, studies on the epidemiology of the virus are necessary for vaccine development. In this study, we collected 94 gout samples from goose farms in the Guangdong Province of South China. Among them, 87 samples (92.6%) tested positive for GoAstV, out of which five GoAstV strains were isolated after four generations of blind transmission through healthy 13-day-old goose embryos. The whole genome of the isolates was sequenced and further analyzed by comparing the sequences with published sequences from China and other parts of the world. The results of the alignment analysis showed that nucleotide sequence similarities among the five GoAstV isolates were around 97.4–98.8%, 98.6–100%, 98.1–99.8%, and 96.7–100% for the whole genome, ORF1a, ORF1b, and ORF2, respectively. These results showed that the GoAstV isolates were highly similar to each other, although they were prevalent in five different regions of the Guangdong Province. The results of the phylogenetic analysis showed that the whole genome, along with the ORF1a, ORF1b, and ORF2 genes of the isolates, were clustered on a single branch, along with the recently published GoAstV-2, and were very distinct from the DNA sequences of the GoAstV-1 virus. In this study, we also reproduced the clinical symptoms of natural infection using the GoAstV-GD2101 isolates, confirming that the gout-causing pathogen in goslings was the goose astrovirus. These findings provided new insights into the pathogenicity and genetic evolution of GoAstV and laid the foundation for effectively controlling the disease.

Epidemiological Investigation of Goose Astrovirus in Hebei Province, China, 2019–2021

“…Previous studies have shown that the mortality rate of goose embryos inoculated with GAstV is as high as 100%. This infection not only severely hinders embryonic development, leading to a significant decline in hatchability, but also causes severe hemorrhage in goose embryos [24]. In this study, we successfully isolated eight GAstV strains from clinical samples and infected goose embryos and observed symptoms similar to those reported in previous research.…”

“…Previous studies have confirmed that the uric acid content in the serum of goslings infected with GAstV significantly increases, reaching a level of 3800 µmol/L on the 15th day post-infection [24]. Previous research revealed that the enzymatic activities and expression levels of xanthine oxidase (XOD) and adenosine deaminase (ADA) in the livers of goslings infected with GAstV are significantly elevated, showing a clear difference compared to those in the livers of uninfected control goslings.…”