Abstract:
Objective The prevalence of waterfowl circoviruses (WFCVs) including goose circovirus (GoCV) and duck circovirus (DuCV) at geese farms was surveyed, and molecular characteristics of the GoCV and DuCV genomes in the first case of natural co-infection on geese studied.
Method From the flocks at geese farms in 6 provinces, 153 tissue specimens were collected during 2023–2024. GoCV and DuCV were detected by using a tri-primer PCR method. Genome sequences of the viruses in samples of the first natural co-infection case were determined.
Result Fifty-three WFCVs were identified from the collected specimens at a positive rate of 34.6%. Of which, 47 were positive for GoCV, 5 for DuCV, and one from Anhui Province (coded AH2367) with both GoCV and DuCV. The whole genome sequence of Go-AH2367 was 1821 nt in length with a homology of 82.9%–99.0% with GoCV and 67.0%–70.9% with DuCV, while that of Du-AH2367 was 1992 nt long with a homology of 84.4%–99.7% with DuCV and 66.1%–68.8% with GoCV. The two major functional proteins of the Go-AH2367 and Du-AH2367(Rep and Cap) were consisted of highly conserved critical motifs with a few sporadic site variations but free of gene recombination, site deletion or insertion on the amino acid sequences. The phylogenetic tree of Go-AH2367 was clustered into an evolutionary branch of the Genotype 1 GoCV isolates, while that of Du-AH2367 of the Genotype 1 DuCV isolates in the same evolutionary branch.
Conclusion The WFCV infections in geese occurred in China were severe. They were mostly the GoCV type with only one confirmed cross-species case that could cause a diverse epidemic. The genomes of Go-AH2367 and Du-AH2367 found in the co-infected goose were genetically stable with no apparent variations by deletion or recombination.
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