Differentiation of infectious bursal disease virus strains by restriction analysis of RT-PCR-amplified VP2 gene sequences

The techniques of reverse transcription-polymerase chain reaction (RT-PCR) and restriction analysis were used to differentiate highly virulent Indian field isolates of infectious bursal disease virus (IBDV) from vaccine strai ns. Primers were designed to amplify the variable region of VP2 gene coding for major virus neutralizing epitopes. The 552 bp PCR products generated f rom four vaccine strains and five field isolates were digested with restric tion enzymes DraI, H12aI, MvaI, StuI, StyI, and TaqI, which could different iate field isolates from vaccine strains. Based on restriction enzyme profi les derived from published sequences, Indian field isolates seem to be clos ely related to highly virulent Japanese, European, and Chinese strains of t he virus.