Isolation,Identification,and Genetic Evolutionary Analysis of a Goose Parvovirus Strain

PENG shan; WANG chao; ZHU Wanjun; ZHANG Jipei; CHEN Jidang

doi:10.19978/j.cnki.xmsy.2025.04.15

Abstract：Goose parvovirus(GPV)is the causative agent of Gosling plague,a highly lethal infectious disease in goslings under 20 days of age,while juvenile geese often exhibit subclinical infections that are frequently overlooked.In November 2024,an acute outbreak occurred in a flock of juvenile geese(56 days old)at a goose farm in Jieyang,Guangdong Province.To identify the cause of the disease,standard necropsy procedures were conducted on the submitted dead geese,and hepatic,splenic,and intestinal tissue samples were aseptically collected.Pathogen nucleic acids of common viral infectious diseases in geese were detected using PCR/RT-PCR assays.The GPV-positive tissue samples homogenized and inoculated into goose embryos.Subsequently,PCR-positive allantois fluid samples were subjected to full-genome cloning and sequencing,followed by phylogenetic and molecular evolutionary analysis based on the obtained sequence data.The results indicated that the submitted tissue samples tested positive for goose parvovirus(GPV)nucleic acid by PCR,while showing negative results for goose circovirus(GoCV),goose astrovirus(GoAstV),Newcastle disease virus(NDV),and Tembusu virus(TMUV).After inoculation of the GPV-positive tissue homogenate into goose embryos,embryo death with severe hemorrhage was observed,and subsequent PCR testing confirmed GPV positivity in the allantois fluid.Genome sequencing revealed that the viral strain possesses a complete genome of 5 028 bp,consisting of inverted terminal repeat(ITR)regions along with non-structural(NS)and capsid(VP)genes.The strain was designated as GPV/GD/3121/2024.Similarity analysis showed that this isolated strain had the highest similarity to the DY16 strain in both the NS1 gene(99.4%)and VP1(95.9%).The GPV/GD/3121/2024 strain exhibits a high whole-genome sequence similarity of 97.5%with recent GPV strains isolated in China,including the DY16,RC16,and HB-2019 strains.Phylogenetic analysis based on the complete genome,non-structural protein NS1,and structural protein VP1 sequences consistently demonstrated that the isolate clustered within a major clade sharing close genetic relationships with European vaccine strain VG32/1)domestic vaccine strains(GDaGPV,SYG61v),and Taiwanese vaccine strain 82-0321V.Additionally,compared to classical GPV strains,GPV/GD/3121/2024 harbored three unique nucleotide mutations in the VP1 gene(A2496T,G2515C,and A2772G),resulting in amino acid substitutions V38L,S178T,and Y491H in the VP1 structural protein.This study confirmed that the lethal outbreak in juvenile geese was caused by GPV infection.The causative strain was successfully isolated and characterized through comprehensive genetic and evolutionary analyses.Furthermore,we summarized the current epidemiological status of GPV in China.These findings provide valuable reference data for understanding the biological characteristics of GPV and formulating scientific control strategies.