| Characterization and comparison of the pathogenicity of viscerotropic velogenic Newcastle disease virus isolates in Korea |
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Jae-Hong Kim1, Haan-Woo Sung2, Il-Hwan Kim1, Eun-Kyoung Lee3, Kang-Seuk Choi3, Daniel Jack King4 |
1Laboratory of Avian Diseases, Research Institute for Veterinary Science, College of Veterinary Medicine,Seoul National University
2College of Veterinary Medicine, Kangwon National University
3Animal, Plant and Fisheries Quarantine and Inspection Agency
4Southeast Poultry Research Laboratory, USDA-ARS |
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| Abstract |
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A total of 18 Newcastle disease virus (NDV) isolates that were recovered from 1949 through 1997 were characterized and pathotyped. All viruses were highly virulent as determined by intracerebral pathogenicity indices ${geq}1.81$ in day-old. These pathotypes are typical for viscerotropic velogenic NDV (VVNDV) pathotype viruses. Some differences were observed for the chicken red blood cell elution rate and thermostability of the hemagglutinin at $56^{circ}C$. Three antigenic groups were identified by a hemagglutination-inhibition assay using NDV monoclonal antibodies. And the predominant gross lesions were as follows: discharge from the nasal cavity, tracheal mucus, petechial hemorrhage in the heart fat, kidney urates and hemorrhage with or without necrosis in the gastrointestinal tract. Severe hemorrhagic or necrotic lesions were also noted in the lymphoid organs and were localized primarily in the spleen and cecal tonsil. However, differences in the occurrence and frequency of the gross lesions were observed between the virus strains. Among them, NDV strains that induced neurological symptoms belonged only to genotype VI. This strain had spread throughout Korea during the late 1980s to the 1990s, which suggests that specific VVNDVs genotypes might result in neurological symptoms. |
| Key Words:
avian paramyxovirus, Newcastle disease, pathogenicity, velogenic neurotropic, viscerotropic velogenic |
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