Pathological Study of SPF Chickens Experimentally Infected with a Chinese IBDV Strain BC6/85

摘要

The purpose of this study was to establish a model of avian viral disease for antiviral drug discovery and development. A Chinese IBDV strain BC6/85 was inoculated into 5-week-old specific-pathogen-free (SPF) male White Leghorn chicken and the clinicopathologic features of disease were compared with those reported before. Birds were monitored clinically and euthanized sequentially with collection of tissues. Tissues were examined by histopathology to observe microscopic lesions, by immunohistochemistry to detect viral protein, by electron microscope to observe ultrastructural changes of the plical epithelium of the bursa of Fabricius and by flow cytometry to detect apoptosis in bursal lymphocytes. Comparing of mean body weight gains and bursal weight indices between control group and virus inoculated groups, significant decreases are displayed. It was observed that the young chickens infected developed the typical histopathological changes of disease. The bursa of Fabricius revealed lesions characteristic of infectious bursal disease and virus particles identical to IBDV were found in the necrotic cells of the follicles. The mucosal surface of the bursal plica was erosion, ulceration and became smooth in the infected chicken groups. And the apoptotic cells were increased after 2 days of the virus inoculation. Morphologically, we clearly demonstrated that replication of IBDV in the bursa during the acute phase of infection and provided new information on the pathogenesis of IBDV.