Genetic Characterization of Infectious Bursal Disease Viruses Associated with Gumboro Outbreaks in Commercial Broilers from Asyut Province, Egypt

Abstract

Ten infectious bursal disease virus (IBDV) field strains were isolated from 15 broiler flocks located in various parts of Asyut, Egypt. Seven strains were subjected to comparative sequencing and phylogenetic analyses to help provide optimal control program for protection against IBDV infection. Sequence analysis of a 530 bp hypervariable region in the VP2 gene revealed that the rate of identity and homology was around 95.6~99.1%. Sequence characterization revealed the 7 strains identified as vvIBDV with the four amino acids residues typical of vvIBDV (242I, 256I, 294I, 299S). The BURSA-VAC vaccine was the nearest vaccine in sequence similarity to the local examined IBDV strains followed by CEVACIBDL then Bursine plus and Nobilis Gumboro indicating its probable success in the face of incoming outbreaks when using these vaccines. Phylogenetic analysis revealed that the presence of three clusters for the examined strains and are grouped with reference very virulent IBDVs of European and Asian origin (Japanese and Hong Kong) strains suggesting the different ancestors of our isolates. The antigenic index showed a number of changes on the major and minor hydrophilic antigenic peaks of the virus surface structures indicating a new genetic evolution of the surface structure epitopes that may lead to vaccination failure and reemergence of the disease.

Characterization of vaccine and field IBDV strains in Ukraine for proper vaccine selection for disease prevention

“…Figure 3 demonstrated that 8 of the examined strains (Ukraine 1517, Ukraine 55, Ukraine 691_35_4, Ukraine 691_35_5, Ukrai ne 760_45_4, Ukraine 2065, Ukraine 934, Ukraine 964) showed the characteristic of vvIBDV amino acid substitutions at residues 222A, 242I (except Ukraine 760_45_4), 256I, 294I, and 299S (except Ukraine 691_35_5). 8 strains had the serine-rich heptapeptide SWSASGS which was found next to the second hydrophilic region 326-332 that confirmed the highly virulence nature among the analyzed strains [14]. In five strains [Ukraine 1517, Ukraine 55, Ukraine 691_35_4, Ukraine 691_35_5, Ukraine 760_45_4] D to N mutation in 212 aa position was found, which was not described before.…”

“…The analyzed region included 142 amino acid residues, from position 206 to 347. It was found that none of the local examined isolates was of vaccine or attenuated origin due to absence of 253-His tidi ne and 284-Threonine mutations that are typically found in attenuated vaccine strains [14,15]. Figure 3 demonstrated that 8 of the examined strains (Ukraine 1517, Ukraine 55, Ukraine 691_35_4, Ukraine 691_35_5, Ukrai ne 760_45_4, Ukraine 2065, Ukraine 934, Ukraine 964) showed the characteristic of vvIBDV amino acid substitutions at residues 222A, 242I (except Ukraine 760_45_4), 256I, 294I, and 299S (except Ukraine 691_35_5).…”

Molecular Characterization of Infectious Bursal Disease Virus From Commercial Poultry in Pakistan

“…Leucine (L) to Serine (S) amino acid change is noted in the same sample [31]. Remaining amino acid alterations were mostly conservative in nature [54][55][56][57]. The changes in the hydrophilic regions of the VP2 protein were important as they are indicative of continuous changes going on in viral genome [58][59][60][61][62].…”

Diagnosis of Clinical Cases of Infectious Bursal Disease Using a Modified Rapid Taq Man-MGB Real-Time RT-PCR Assay

“…Modified Rapid Taq Man-MGB Real-Time RT-PCR Assay 231 and producing IBDV typical lesions [7]. IBDV is a non-enveloped icosahedral virus with a diameter of 60 nm and its genome consists of two segments of double stranded RNA (segments A and B) [2].…”