Sequence comparison of the VP2 variable region of infectious bursal disease virus isolates from Vietnam

The variable legion in the VP2 gene of twenty-three infectious bursal disea se virus (IBDV) isolates, collected in Vietnam in 1997 and 1998, was amplif ied as cDNA by using the reverse transcription-polymerase chain reaction an d sequenced. Analysis of amino acid substitutions and phylogenetic relation ships of the deduced amino acid sequences (residues 206-350) showed that th e nineteen Vietnamese vv IBDVs clustered with the European vv IBDVs, Japane se vv IBDVs and Chinese vv strains, and that the four Vietnamese virulent s trains were closely related to European virulent strain 52/70. These result s suggest that Vietnamese vv IBDVs, European vv IBDVs, Japanese vv IBDVs an d Chinese vv strains have the same origin.