Comparison of Pathogenicity of Porcine Deltacoronavirus Cz2020 from Cell Culture and Intestinal Contents in 27-Day-Old Piglets

Porcine deltacoronavirus (PDCoV) is an emenging swine enteropathogenic coronavirus that can cause high mortality rate. Little is known regarding the pathogenicity of PDCoV against 27-years-old piglets. In this study, piglets were experimentally infected with PDCoV from cell culture, the challenged piglets do not have obvious symptoms from 1 to 7 days post-challenge (DPC), while viral shedding was detected in rectal swab at 1 DPC. Tissues of small intestines displayed slight macroscopic and microscopic lesions with no viral antigen detection. On the other hand, 27-years-old piglets were infected with PDCoV from intestinal contents, the piglets developed mild to severe diarrhea, shedding increasing from 2 to 7 DPC, and developed macroscopic and microscopic lesions in small intestines with clear viral antigen confirmed by immunohistochemistry staining. Diarrhea caused by PDCoV from intestinal contents in 27-day-old piglets is less reported. Thus, our results might provide new insights into the pathogenesis of PDCoV.