Real-Time Rt-Pcr Based On Genome Segment B For The Detection Of Infectious Bursal Disease Virus

Infectious bursal disease (IBD, Gumboro disease) is one of the most important viral diseases in poultry with high economic impact world wide. The causative agent is the infectious bursal disease virus (IBDV). At the end of the 80's very virulent (vv) IBDV strains emerged in Europe. These strains are able to break through protection provided by maternally derived antibodies as well as by vaccination. At present, the identification of these strains is complicated as they do not replicate in common tissue culture and cannot be differentiated from vaccine strains by serological methods. In this communication a real-time RT-PCR protocol using SYBR-green(R) is described for the rapid and reliable detection of serotype I IBDV strains. Restriction enzyme analysis of the products obtained allows the identification of vvIBDV strains. This method was validated with serotype I IBDV reference strains with differences in virulence and was then used for the identification and typing of 4 field strains isolated in Iran. Three of these isolates were classified as vvIBDV strains, whereas I isolate belongs to the group of classical virulent IBDV strains. Here the existence of vvIBDV strains in Iran is described for the first time.