Characteristics of very virulent infectious bursal disease viruses isolated from Chinese broiler chickens (2012-2013)

- VP2 genes of nine vvIBDVs were phylogenetically analyzed in this study.
- Nine isolates were highly similar to each other and other reference vvIBDVs.
- Our results confirm the circulation of vvIBDVs in Chinese broiler chicken farms.
- Our results confirm the nucleotide substitution rate in VP2 is relatively slow.