Genetic Diversity of Recent Infectious Bursal Disease Viruses Isolated From Vaccinated Poultry Flocks in Malaysia

Vaccination is an essential component in controlling infectious bursal disease (IBD), however, there a lack of information on the genetic characteristics recent virus (IBDV) that was isolated from IBD vaccinated commercial flocks Malaysia. The present study investigated 11 IBDV isolates were poultry farms. detected using reverse transcription-polymerase chain reaction (RT-PCR) targeting hypervariable region (HVR) VP2. Based HVR sequences, five (IBS536/2017, IBS624/2017, UPM766/2018, UPM1056/2018, and UPM1432/2019) selected for whole-genome sequencing MiSeq platform. nucleotide amino acid (aa) sequences compared with previously characterized strains. Deduced aa VP2HVR revealed seven 94–99% identity to very virulent strains (genogroup 3), two 97–100% variant 2), 100% vaccine strain 1) IBDV. phylogenetic analysis also showed formed clusters respective genogroups. characteristic motifs 222T, 249K, 286I, 318D are typical observed UPM1219/2019 UPM1432/2019. In comparison, residues such as 222A, 249Q, 286T, 318G found vvIBDV, except UPM1056/2018 A222T substitution. addition, isolate has substitutions D213N, G254D, S315T, S317R, A321E not commonly reported vvIBDV Unlike other vvIBDVs this study, UPM766/2018 lacks MLSL VP5. tripeptides 145/146/147 (TDN) VP1 conserved while different motif, NED, Malaysian strain. tree clustered American Chinese viruses highly comparable novel variants, 99.9% identity. analyses, first identification being Further research required determine pathogenicity protective efficacy current vaccines used against virus.