Background and Aims: Avian infectious bronchitis (IB) has prevalent in the most chicken farms during recent years, in spite of the IB vaccination program which has been widely performed in Iran. To better understand the molecular epidemiology of IBV in Iran, the full length sequences of S1 gene of Iranian QX IBVs were determined and phylogenetic analysis was done using some sequences of IBV.
Materials and Methods: To better understand the molecular epidemiology of IBV in Iran, the full length sequences of S1 gene of Iranian QX IBVs were determined and phylogenetic analysis was done using some sequences of IBV.
Results: Iranian QX IBVs were located in LX4 (Cluster 2). The nucleotides homologies were 99.52% - 100% between the isolates. Phylogenetic analysis revealed that all the IBV isolates were very similar and probably had a common origin. The hyperactive variable regions of S1 were determined.
Conclusions: The results from this study and other published results in the GenBank database showed that the isolates circulating in Iran in recent years were mainly LX4 (Cluster 2) genotype, which is the predominant genotype circulating in Iran in recent years (After first report of QX IBV in Iran, 2011). This finding provides important information on IBV evolution in Iran.