Fig. 1. Pathological lesions and immunohistochemical analyses of CPV-2 infected pangolins (sub-adult females) suffering from severe diarrhea. Representative images of gross changes and histopathological lesions are shown. Panel A presents a gross observation of the internal organs, showing apparent congestion and hemorrhage. Panels B and C show histopathological lesions in the jejunum. Pronounced injury in the mucosa layer of small intestine is a prominent feature, notably the necrosis and shedding of the intestinal mucosal intraepithelial cells and glands. Panels D and E show the immunohistochemistry results for the jejunum and ileum, respectively. The black arrows indicate the significant pathological lesion or CPV antigen-positive area. Scale bars are shown in the lower right-hand corners.
Virus screening, isolation, and transmission electron microscopy observations
The findings of our PCR analyses revealed that samples obtained from the two pangolins were CPV-positive, whereas there was no evidence to indicate infection with CCoV, CDV, or DogCV. Moreover, typical parvovirus-associated CPV were detected after four passages in F81 cells, and typical parvovirus-like particles, approximately 20 nm in diameter, were observed in the cell supernatants (Fig. 2). Based on these observations, we believe CPV-2s to be the etiological agents causing pangolin diarrhea.