Detection of very virulent infectious bursal disease virus from a field outbreak in Central India.

In order to detect infectious bursal disease virus (IBDV), bursal tissue was collected from 10 IBD-suspected birds from a 30-day-old, IBDV-vaccinated commercial broiler chicken flock of 2000 birds exhibiting clinical signs suggestive of infectious bursal disease (IBD). The presence of IBDV was confirmed by partial amplification of the VP2 gene by reverse transcription and polymerase chain reaction. Isolates were identified as very virulent strains of IBDV (vvIBDV) by nucleotide sequence analysis. The comparison of the VP2 nucleotide sequences among the isolates revealed the presence of single-nucleotide polymorphisms in the VP2 gene of IBDV in the same flock. The comparative analysis indicated that these viruses were genetically close to the vvIBDVs previously detected in India. Our analysis provided information about the existence of vvIBDV in Central India.