| pubmed-article:12387501 | pubmed:abstractText | Two infectious bursal disease virus (IBDV) isolates were obtained from commercial poultry farms with a history of severe outbreaks. A 474-bp product encompassing hypervariable region of IBDV VP2 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR). The nucleotide sequences of two isolates, VMB1 and VMB2, were determined and compared with those of twenty IBDV strains, including seven very virulent, four classical virulent, four classical attenuated, three antigenic variants and two avirulent serotype 2 strains. The two isolates showed a similarity of 96.5-98.4% with very virulent strains, 84.6-94.6% with classical virulent strains, 90.0-91.4% with classical attenuated strains, 83.0-91.9% with antigenic variants and 65.8-68.7% with avirulent strains. The deduced amino acid sequences of the two isolates showed amino acid substitutions of V256I, N279D, L294I and N299S, specific for very virulent strains. Phylogenetic analysis showed that the two isolates, along with a reported very virulent Indian strain, were closely related to European, Japanese and Chinese very virulent strains indicating their evolutionary origin. | lld:pubmed |
