Characterization of Newcastle disease viruses isolated in Italy in 2000

Thirty-two Newcastle disease virus isolates from the 2000 Italian epidemic were characterized by monoclonal antibody binding pattern and nucleotide sequencing of approximately 400 base pairs of the fusion gene. In addition, the pathogenicity of six of these isolates was assessed by means of the intracerebral pathogenicity test (ICPI). The strains tested exhibited an ICPI ranging from 1.6 to 2.0. On the basis of the monoclonal antibody binding pattern, all isolates could be classified as belonging to group C1. Both monoclonal antibody and genomic analysis revealed a very high degree of homology, indicating a common source of infection. On the basis of the phylogenetic analysis, it appears that the Italian isolates are closely related to the recent isolates from the UK, Scandinavia and South East Europe, thus suggesting the circulation of this viral strain in Europe during the past 5 years.