Genetic Characterization of Infectious Bursal Disease Viruses Associated with Gumboro Outbreaks in Chicken Flocks from El-Sharkia Province, Egypt

Re-emergence of very virulent forms of IBDV has been the cause of significant economic losses in poultry industry in Egypt. In present study, 15 bursal samples were collected from flocks showing typical clinical signs and post mortem lesions of IBDV outbreaks. These bursal samples were tested using reverse transcriptase-polymerase chain reaction (RT-PCR) targeting VP2 gene of IBDV. Out of the tested samples 10 (66.67%) were positives. Sequence analysis of PCR products of 4 selected samples according to strength of the bands on gel electrophoresis was carried out. All of the sequenced samples were characterized as very virulent (vvIBDV). The deduced amino acid sequence revealed that the four samples (Sharkia1,2,3,4) have amino acid sequence identity between each other (99.3 -100%) and between Egyptian vvIBDV (Giza 2008, Giza 2000) strains (98.6 – 100%). Genotyping of the four Egyptian vvIBDVs indicated that they were closely related to previous isolated strains from Egypt. So we aimed to find the homology between these collected IBDV samples and other field and vaccinal strains sequences.