Molecular Characterization and Pathogenicity of the Novel Recombinant Muscovy Duck Parvovirus Isolated from Geese

SIMPLE SUMMARY: Waterfowl parvoviruses are important pathogens that cause severe disease in young waterfowl. Waterfowl parvoviruses can be divided into goose parvovirus (GPV)- and Muscovy duck parvovirus (MDPV)-related groups. New variant strains can be generated from genomic recombination between different waterfowl parvoviruses and result in new epidemics. Recently, a novel recombinant MDPV (rMDPV) derived from recombination between GPVs and MDPV was reported. This virus caused high morbidity and mortality rates in ducklings and was circulating in waterfowl in mainland China. In this study, a novel rMDPV was isolated in Taiwan from a goose flock that experienced a high mortality. The complete genome of this goose-origin rMDPV was sequenced. Phylogenetic and recombination analyses were performed to elucidate its molecular characteristics. The virulence of this rMDPV was evaluated using experimental infection goose embryos and goslings. This study was the first report showing the pathogenicity of rMDPV in geese. ABSTRACT: Goose parvovirus (GPV) and Muscovy duck parvovirus (MDPV) are the main agents associated with waterfowl parvovirus infections that caused great economic losses in the waterfowl industry. In 2020, a recombinant waterfowl parvovirus, 20-0910G, was isolated in a goose flock in Taiwan that experienced high morbidity and mortality. The whole genome of 20-0910G was sequenced to investigate the genomic characteristics of this isolate. Recombination analysis revealed that, like Chinese rMDPVs, 20-0910G had a classical MDPV genomic backbone and underwent two recombination events with classical GPVs at the P9 promoter and partial VP3 gene regions. Phylogenetic analysis of the genomic sequence found that this goose-origin parvovirus was highly similar to the circulating recombinant MDPVs (rMDPVs) isolated from duck flocks in China. The results of experimental challenge tests showed that 20-0910G caused 100% mortality in goose embryos and in 1-day-old goslings by 11 and 12 days post-inoculation, respectively. Taken together, the results indicated that this goose-origin rMDPV was closely related to the duck-origin rMDPVs and was highly pathogenic to young geese.