Sequence analysis of the VP2 gene hypervariable region of infectious bursal disease viruses from India

Attempts have been made to characterize infectious bursal disease virus (IB DV) isolates collected from different parts of India during 1993 to 1999. P hylogenetic analysis was performed on a sequence generated by cycle sequenc ing comprising the variable region of the VP2 gene of 14 isolates. Indian I BDV isolates had divergence of 0.2 to 4.3% at nucleotide and 0 to 2.2% at a mino acid levels among themselves. Nine nucleotide changes were found in In dian IBDV field isolates, resulting in the four specific amino acid changes at 222P-A, 256V-I, 294L-I and 299N-S, reported regularly in very virulent isolates. One of the Indian IBDV isolates, UP1/99, had change D to N at pos ition 212 in the first hydrophilic region. The serine-rich heptapeptide seq uence 'SWSASGS' was conserved in all the isolates. Phylogenetically, all In dian field isolates were found to be closely related to very virulent IBDV isolates from Europe, Japan, China and Israel.