Submitted to: Proceedings of Southern Conference on Avian Diseases
Publication Type: Abstract Only
Publication Acceptance Date: 11/27/2001
Publication Date: 1/15/2002
Citation: Interpretive Summary:
Technical Abstract: Newcastle disease virus (NDV) isolates recovered from wild (anhinga) and exotic birds (pheasant and dove) were passaged four times in chickens prior to this pathogenesis study. Groups of ten four-week-old SPF White Leghorn chickens, inoculated by eye drop with each of the passaged isolates, were observed for clinical disease and were sampled at 2, 5, 10, and 14 days post-inoculation (dpi) or at the occurrence of mortality. Tissues were examined by histopathology, by immunohistochemistry (IHC) for presence of NDV nucleoprotein, and by in situ hybridization (ISH) for mRNA using a digoxigenin-labeled riboprobe to the NDV matrix gene. Birds inoculated with the pheasant and dove isolates had severe disease, characterized by marked depression, and died at 4 and 5 dpi, respectively. Although birds inoculated with the Anhinga isolate did not show clinical signs, mild to severe lymphoplasmacytic encephalitis was detected histologicaly at 2, 5, 10 (more prominent), and 14 dpi. Severe diffuse lymphocellular necrosis of the lymphoid organs and aggregates was the main histologic finding in birds inoculated with the Pheasant and Dove isolates. Viral nucleoprotein and viral mRNA were detected by IHC and ISH, respectively, among all the affected organs. The results demonstrate that moderate to highly virulent NDV isolates from wild and exotic birds represent a serious threat for commercial poultry flocks.