Characterization of natural co-infection with goose astrovirus genotypes I and II in gout affected goslings

ABSTRACT

In recent years, goose astrovirus (GoAstV) has emerged as the primary pathogen responsible for gout in goslings aged 1–20 days. This study presents a case of natural co-infection with GoAstV genotypes I and II in goslings afflicted with gout at 12 days of age. A post-mortem examination revealed the presence of urate deposits in the internal organs and within the coxofemoral joints. Histopathological analysis revealed congestion, haemorrhage, parenchymal cell necrosis, lymphocytic infiltration in the liver and kidney, and urate tophi in the kidneys, liver, spleen, and lungs. Reverse transcription polymerase chain reaction (RT–PCR) and sequencing were performed to identify GoAstV-I and II open reading frame (ORF) 2 genes in the liver and kidney tissues, respectively. Immunofluorescence staining confirmed the co-expression of GoAstV-I and II antigens in the kidney. A homogenate from pooled liver and kidney tissues was inoculated onto Leghorn male hepatoma cells and passaged five times. The RT–PCR and immunofluorescence assay verified the successful isolation of GoAstV-II, whereas GoAstV-I could not be isolated. Sequence analysis demonstrated that both GoAstV-I (7255 nt) and GoAstV-II (7116 nt) exhibited typical structural arrangements and a series of conserved regions in astroviruses. Phylogenetic analysis revealed that the amino acid sequence of the full-length ORF2 between GoAstV-I and GoAstV-II had 42.5% homology, indicating that these viruses should be classified as different GoAstV genotypes. These findings contribute to our understanding of GoAstV characterization and provide a basis for the development of strategies to control these viruses.

RESEARCH HIGHLIGHTS

• Urate tophi were found in the kidneys, liver, spleen and lungs.

• IFA confirmed the co-expression of GoAstV-I and II antigens in the same kidney.

KEYWORDS:

• Goslings
• gout
• co-infection
• goose astrovirus
• histopathology
• virus isolation
• sequence analysis

Acknowledgements

The authors express their gratitude to Prof. Ye Jianqiang (College of Veterinary Medicine, Yangzhou University, China) for kindly providing anti-GoAsTV-II ORF2 monoclonal antibody.

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

HL and QZ designed the experiments, analysed the data, and wrote the manuscript. YC, CW, HW and HX performed the experiments. HL and KQ performed the histopathological analysis. All authors reviewed the draft of this manuscript.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon request. The nucleotide sequences obtained in this study were submitted to GenBank and obtained GenBank accession numbers.