As. Pac. J. Mol. Biol. & Biotech., Dec 2002 Vol. 10 (2) : 89-96

Molecular Characterization of Malaysian Isolate of Very Virulent Infectious Bursal Disease Virus

S. F. Phong, M. Hair-Bejo^*, A. R. Omar and I. Aini

Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.

Abstract.

The 1.35-kb fragment of P97/302 infectious bursal disease virus (IBDV) VP2 gene, encompassing the hypervariable region was successfully amplified by the reverse transcriptase/polymerase chain reaction (RT/PCR). This isolate was cloned and sequenced. The sequenced was analyzed and compared to other eight reference IBDV strains. This isolate has amino acid substitutions at the 222(A), 256(I), 294(I) and 299(S) as other reported reference vv (very virulent) strains of UK661, HK46 and OKYM. The amino acid residues at the two hydrophilic regions and the serine-rich heptapeptide region of the P97/302 are the same as vv strains of UK661, HK46 and OKYM. The P97/302 IBDV isolate can be digested with enzymes TaqI, StyI, SspI but not with SacI as previously reported in many others vv strain. Phylogenetic analysis based on the nucleotide sequence of hypervariable region showed that this isolate clustered with the vv strains of UK661, HK46 and OKYM and distinct from other groups of classical, attenuated and variant strains. It was concluded that this P97/302 IBDV isolate was serotype 1, vv IBDV strain.

Key words: Very Virulent Infectious Bursal Disease

^*Author for Correspondence.