Molecular Characterization of Infectious Bronchitis Virus in Chicken

Abstract

INFECTIOUS BRONCHITIS (IB) is a highly contagious ………disease of serious economic importance in the poultry industry worldwide. Diagnosis of Infectious Bronchitis Virus (IBV) infections in Egypt during 2013 - 2016 among poultry flocks. A total of 41 chicken flocks were examined (40 broiler flock and one breeder flock). Results revealed that 21 chicken flocks were found positive IBV by N gene conventional RT-PCR and real time RT-PCR. The samples were isolated and propagated in commercial embryonated chicken eggs (ECE) with result revealed that only one sample that showed curling and dwarfing of the embryo after the second passage while 10 samples were HA positive that suggest mixed infection of IBV with other viruses such as Newcastle Virus or Avian Influenza Virus. Furthermore, the allantoic fluids of the positive samples were subjected to specific S1 PCR to differentiate strains of IBV. The absence of positive reaction of S1gene conventional RT-PCR may confirm the involvements of other respiratory pathogens in chickens as Newcastle disease, avian influenza and mycoplasmosis that masked IBV infections. In conclusion, our results confirmed the detection of IBV in chicken flocks in Egypt which responsible for the respiratory problems in poultry farms and diagnosis with Real-time PCR because it is more rapid, sensitive, and reproducible, and the risk of carryover contamination is minimized compared to conventional PCR.