Avian Coronavirus: Case of Infectious Bronchitis Virus Pathogenesis, Diagnostic Approaches, and Phylogenetic Relationship Among Emerging Strains in Middle East and North Africa Regions

Infectious bronchitis (IB) virus (IBV) is a very dynamic and evolving virus, causing severe diseases in poultry with significant economic consequences to the poultry industry worldwide, affecting chickens of all ages and possessing a major threat to the poultry industry. IBV is well studied worldwide; nevertheless, in Middle East and North Africa (MENA) regions, epidemiological and scientific data are poor and not updated. In spite of regular vaccination with Massachusetts (Mass) strain has been available to control IB for many decades in MENA regions, which it is most commonly used, the protection is not occurred. However, the continuity of the spread of IBV has shown the emergence of multiple variant strains due to the frequent point of mutations and recombination events in the S1 gene hypervariable regions. All the reported IBV variants circulate in the form of several serotypes/genotypes that can be partially or poorly neutralized by current vaccines. This emergence remains a problem for the poultry industry and vaccine manufacturers. Therefore the objective of this present chapter, which is reported for the first time, aims to establish phylogenic relationship among emerging strains in MENA regions.