Submitted to: American College of Veterinary Pathologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/10/2001
Publication Date: 9/10/2001
Interpretive Summary: Interpretive Summary not required.
Technical Abstract: Three Newcastle disease virus (NDV) isolates recovered from wild (anhinga) and exotic birds (pheasant and dove) were passaged four times in domestic chickens for this 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 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 histologically at 5, 10 (more prominent), and 14 dpi. Severe diffuse lymphocellular necrosis of th lymphoid organs and tissues was the main histologic finding in birds inoculated with the pheasant (at 4 dpi) and dove (at 4 and 5 dpi) isolates. Viral nucleoprotein and viral mRNA were detected by IHC and ISH, respectively, among all the affected organs. The results of this study demonstrate that moderate to highly virulent NDV isolates from wild and exotic birds represent a serious threat for commercial poultry flocks.