Isolation and Molecular Characterization of
Infectious Bronchitis Virus (IBV) Variants Circulating in Commercial
Poultry in Pakistan
Saba Rafique1, 2*, Naila Siddique1,
Muhammad Athar Abbas1, Aamer Ali Shah2, Adeela
Sharif1 and Khalid Naeem1
1National
Reference Lab for Poultry Diseases, Animal Sciences Institute,
National Agricultural Research Centre, Islamabad-45500; 2Department
of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan *Corresponding author: sabarafique@ymail.com
Abstract
Avian infectious bronchitis is a contagious viral
disease of chicken. It is present everywhere in the world where poultry is
reared. This study was designed to detect, isolate and sequence the circulating
Infectious bronchitis viruses (IBVs) in poultry in Pakistan. Out of 905 clinical
specimens tested, 358 were found positive for IBV, having serotype distribution
of Mass (43%), 4/91 (51%), and different variants of IBV (5%), respectively. One
of the variants recovered from broiler-breeder (BB) flock and designated as
Pak-973, was further propagated and characterized on molecular basis. Virus
neutralization test did not neutralize it with the reference antisera IBV
serotypes M41, 4/91, D274, D1466 and IT-02, identifying it as a distinct
serotype. Furthermore, Haemagglutination Inhibition test (HI) has proven useful
in differentiating various serotype of IBV. In addition to this, partial Spike 1
(S1) gene was amplified by reverse transcriptase-PCR (RT-PCR) and subjected to
sequencing for determining its genetic diversity. Sequenced data was submitted
in the GenBank and the IBV isolate named as KX013102_NARC/973_Pakistan_2015. The
phylogenetic analysis of Pak-973 showed a maximum homology of 93% with the
Indian IBV variant KF360983_23/B/2008_India. However, an overall nucleotide
homology with some other Indian isolates is between 82-93%. This study revealed
the presence of IBV variant isolates in the field in Pakistan during 2015.
To Cite This Article:
Rafique S, Siddique N, Abbas MA, Shah AA, Sharif
A and Naeem K, 2018. Isolation and molecular characterization of infectious
bronchitis virus (IBV) variants circulating in commercial poultry in Pakistan.
Pak Vet J, 38(4): 365-370. http://dx.doi.org/10.29261/pakvetj/2018.071