The newly emerging duck-origin goose parvovirus in China exhibits a wide range of pathogenicity to main domesticated waterfowl.

Short beak and dwarfism syndrome virus (SBDSV) is a newly emerging distinct duck-origin goose parvovirus that belongs to the genus Dependovirus. Our previous studies have found that SBDSV was highly pathogenic to Cherry Valley ducklings and mule ducklings. However, little is known about its pathogenicity to other waterfowls. In the present study, the pathogenicity of SBDSV was evaluated in domesticated waterfowl including Muscovy ducklings, Sheldrake ducklings and domestic goslings. All experimentally infected birds exhibited remarkable growth retardation, anorexia and diarrhea similar to naturally infected birds. Interestingly, atrophic beaks and protruded tongues were not observed in all infection groups. At necropsies, no diagnostic pathological lesions were observed. Viral antigens existed in most organ tissues such as heart, liver, spleen, kidney, pancreas and intestine. All ducks in Muscovy duckling and Sheldrake duckling infected groups and 70% goslings in infected groups were seropositive for goose parvovirus (GPV) antibodies at 21dpi with the average titers as 28.4, 26.9, 24.0, respectively. Muscovy ducklings were more prominent in viral load and weight loss with a higher GPV antibodies titer than Sheldrake ducklings and goslings. Taken together, SBDSV exhibits a wide range of pathogenicity to main domesticated waterfowl with variable symptoms and cause considerable economic losses in China.

Isolation and characterization of a distinct duck-origin goose parvovirus causing an outbreak of duckling short beak and dwarfism syndrome in China.

Many mule duck and Cherry Valley duck flocks in different duck-producing regions of China have shown signs of an apparently new disease designated "short beak and dwarfism syndrome" (SBDS) since 2015. The disease is characterized by dyspraxia, weight loss, a protruding tongue, and high morbidity and low mortality rates. In order to characterize the etiological agent, a virus designated SBDSV M15 was isolated from allantoic fluid of dead embryos following serial passage in duck embryos. This virus causes a cytopathic effect in duck embryo fibroblast (DEF) cells. Using monoclonal antibody diagnostic assays, the SBDSV M15 isolate was positive for the antigen of goose parvovirus but not Muscovy duck parvovirus. A 348-bp (2604-2951) VP1gene fragment was amplified, and its sequence indicated that the virus was most closely related to a Hungarian GPV strain that was also isolated from mule ducks with SBDS disease. A similar disease was reproduced by inoculating birds with SBDSV M15. Together, these data indicate that SBDSV M15 is a GPV-related parvovirus causing SBDS disease and that it is divergent from classical GPV isolates.