Differential Susceptibility to Porcine Deltacoronavirus: Ducks Show Greater Vulnerability Than Geese.

Porcine deltacoronavirus (PDCoV), an enteropathogenic coronavirus belonging to the genus, is globally distributed and represents a significant viral enteric disease in pigs. It primarily causes severe diarrhea in pigs, especially in newborn piglets, with high fatality rates, resulting in substantial losses to the pig farming industry. Notably, PDCoV is also recognized as a zoonotic virus. PDCoV is a coronavirus that can infect both birds and mammals, including humans, thereby potentiating its zoonotic prevalence. However, the PDCoV circulation among birds and mammals remains poorly understood. Considering the close relationship and large farming numbers of domestic waterfowl, they may play crucial roles in PDCoV interspecies transmission, albeit their susceptibility remains unknown. In this study, we investigated the susceptibility of specific pathogen free (SPF) Shaoxing ducks and clean (CL) animal Chinese white geese to PDCoV. These results indicated that Shaoxing ducks and Chinese white geese are susceptible to PDCoV infection, viral RNA can be detected in intestines, parenchymal organs, and feces, though the clinical signs of diarrhea in ducks are significantly more severe than in geese. Histopathological analysis revealed obvious lesions in the intestines of infected Shaoxing ducks, while no lesions were observed in Chinese white geese. Moreover, the infected ducks exhibited diarrhea, and PDCoV seroconversion occurred 14 days postinoculation (dpi). Thus, our study broadens the spectrum of PDCoV hosts and provides valuable information for further investigation of PDCoV interspecies transmission. Waterfowl, especially ducks, may play an important role in the inter-species transmission of the PDCoV.