Distribution of duck-origin parvovirus over time in Cherry Valley ducks in vivo and histopathological investigation

In 2015, we successfully isolated a strain of duck-origin parvovirus from Cherry Valley ducks, which we named QH-L01. In this study, duck-origin parvovirus in Cherry Valley ducks was quantified and localized by quantitative real-time PCR (qPCR) and immunohistochemistry (IHC), and pathological damage to the tissues and organs was observed by hematoxylin-eosin staining (HE staining). qPCR showed that the viral load was higher in the spleen, brain, lung, cecum, ileum, and duodenum over time. The results from IHC experiments showed positive reactions in hepatocytes, epithelium of the lung atrium, myocardial cells, goblet cells of the intestine, and brain cells. Primary histological examination revealed pulmonary lobule depletion and dilation in the lung as well as necrosis and erosion of the villus tips in the duodenum, ileum and cecum. This study is the first demonstration that duck-origin parvovirus can be transmitted from the spleen to the brain and lung, resulting in proliferation and dissemination of the virus to the cecum, ileum, duodenum and other tissues through the blood. The lung, duodenum, ileum and cecum may thus represent the main target tissues and organs for duck-origin parvovirus.