Background: A novel avian infectious bronchitis virus (IBV), Egypt/Qal/014p was isolated from 14-day-old broiler chickens with proventriculitis in Qaluobia province of Egypt in 2014.
Objective: The isolate was identified by a real time RT-PCR targeting the nucleocapsid (N) gene with further genetic and antigenic characterization
Methods: Beside a real time RT-PCR; sequence analysis of partial S1 gene, cross-neutralization and
the challenge experiment for H120 vaccinated broiler chickens were also performed.
Results: Egypt/Qal/014p had close relation with that of the Massachusetts prototypes. Comparisons
nucleotide and amino acid sequence of partial S1 gene showed that the recent isolate had 98.2% and
95.2% nucleotide similarities and 96.8% and 91.4% amino acid similarities with the commonly used
IBV vaccine Massachusetts strains H120 and M41 respectively. Egypt/Qal/014p had a unique amino
acid substitution at residues 39 (Serine), 40 (Tyrosine), 41 (Lysine), 64 (Glutamate) and 69 (Valine) of
the S1 proteins from H120 and M41.The cross-neutralization test revealed antigenic relatedness of
Egypt/Qal/014p with Massachusetts serotypes. The commercial H120 vaccine conferred partial
protection against proventriculitis induced by Egypt/Qal/014p.
Conclusion: IBV strains exhibiting proventriculitis were found co-circulating in broiler chickens in
Egypt and optimum control of IBV in Egypt require preparation of vaccine from indigenous isolates
beside periodic evaluation of cross-protective capabilities of such vaccine |
