Pathogenicity of Pekin duck- and goose-origin parvoviruses in Pekin ducklings

Goose parvovirus (GPV) usually affects goslings and Muscovy ducks but not Pekin ducks. Earlier works showed that a variant GPV can cause short beak and dwarfism syndrome (SBDS) in Pekin ducks. Here, we investigated the pathogenicity of a variant GPV of Pekin duck-origin (JS1) and a classical GPV of goose-origin (H) in Pekin ducklings. Following intramuscular infection at two days of age, both JS1 and H strains influenced weight gain and development of beaks and bones of wings and legs, and caused microscopic lesions of internal organs of ducks. However, the clinical signs typical of SBDS could only be replicated with the JS1 isolate. The findings suggest that both variant and classical GPVs are pathogenic for Pekin ducklings, while the former is more virulent than the latter. Using a quantitative real-time PCR assay, high levels of viral load were detected from bloods, internal organs, leg muscles, and ileac contents in JS1- and H-infected ducks from 6 h to 35 days postinfection (DPI). Using a GPV VP3-based ELISA, antibodies in sera of JS1- and H-infected ducks were detectable at 1 DPI and then persistently rose during the subsequent five weeks. These results suggest that both variant and classical GPVs can infect Pekin ducklings. The present work contributes to the understanding of pathogenicity of GPV to Pekin ducks and may provide clues to pathogenesis of GPV-related SBDS.