Genotyping of Infectious bronchitis viruses isolated from broiler chicken farms in Iran during 2015-2016

BACKGROUND: Avian infectious bronchitis is considered as an important viral disease worldwide. Genotyping based on the S1 subunit of spike protein gene of the causative agent, avian infectious bronchitis virus, can be used to classify IBV isolates. Objective: This survey was carried out to characterize the infectious bronchitis virus (IBV) genotypes circulating in Iran and determine their prevalence rate. METHODS: In this survey, 100 samples of trachea were collected from broiler chickens suspected to IBV during 2015 to 2016. Nested polymerase chain reaction (Nested PCR) followed by S1 gene sequencing was applied to genotype the detected isolates. RESULTS: In this survey, forty five isolates were detected and classified in four distinct genotypes, variant 2 [IS/1494/06], 4/91, QX and Massachusetts, based on phylogenetic analysis. The prevalence rates of the variant 2 [IS/1494/06], 4/91, QX and Massachusetts were 66.67%, 24.45%, 4.44% and 4.44%, respectively. CONCLUSION: This survey demonstrates the epidemiology of IBV genotypes in Iran and provides an insight into the evolution of these strains. Moreover, it is clarified that IBV genotypes prevalence are constantly changing in a region.