Infectious Bronchitis Virus Genotype GI-23: Emergence, Evolution and Widespread -

Avian Infectious Bronchitis (IBV) is a contagious viral disease that causes severe losses in the poultry industry all over the world. Since the 1950s, IBV circulates in the Middle East and North Africa without tangible effects of the taken control measures on its spread or evolution. Furthermore, the IBV isolation of new variants never stops. Although several genetic studies on the IBV were conducted, however, many IBV strains from the region have been either misclassified or even unclassified due to the variable criteria in these studies. The genotype-23 (GI-23) emerges and prevails in the Middle East and continuously evolved either by inter- and/or intra-genotypic recombination in poultry and wild bird species. Subsequently, the GI-23 emerged and started to spread through Europe and Asia. Many protection studies conducted against the circulating strains are not standardized according to the known regulatory requirements. In this review, we provide an overview of the evolution, genetic diversity of IBV genotypes especially the GI-23 genotype. The high prevalence of IBV GI-23 strains necessitates the adoption of vaccination schemes using GI-23 based vaccines