Molecular characterization of infectious bronchitis viruses isolated from broiler chicken farms in Iran, 2014-2015

Abstract

Infectious bronchitis (IB) is a viral avian disease with economic importance in the world, including Iran. S1 gene sequencing has been used for molecular epidemiological studies and genotypic characterization of infectious bronchitis virus (IBV). A total of 118 IBV isolates were obtained from tissue samples from chickens with clinically suspected IB from Iranian broiler farms (eight provinces, 200 samples). The isolates were confirmed by real-time polymerase chain reaction (PCR) and characterized by sequencing the spike glycoprotein gene. The isolates formed six distinct phylogenetic groups (IS/1494/06 [Var2] like, 4/91-like, IS/720-like, QX-like, IR-1 and Mass-like) that were related to variants isolated in the region. The most frequently detected viruses were of the Var2-like (IS/1494/06-like) genotype, with an overall prevalence of 34 %. Twenty-one percent of the isolates formed a cluster together with the 4/91 IBV type, 10 % were of the QX genotype, and 8 % were of the IS/720 genotype. In addition, 4 % and 3 % of the isolates belonged to the Massachusetts and IR-1 genotype, respectively. For the first time, we have isolated and characterized IBV variants from broiler farms in different provinces of Iran. This study demonstrates a constant evolution of IBV in Iran, demonstrating the need for continuous monitoring and development of new vaccines based on indigenous viruses.

Phylogenetic analysis and full-length characterization of S1 gene of IS-1494 (Variant 2) like infectious bronchitis virus isolates, Iran, 2015

“…Later other viruses, which were highly related to Variant 2 (IS/378/97, IS/ 572/98, IS/585/98, IS/589/98), recovered from the respiratory or renal disease in Israel (Callison et al, 2001). The isolation of IS/1494/06 IBV, one of the Israeli Var2 isolates (Callison et al, 2001), and information on its S1 gene sequence in GenBank (EU350551) was first reported by Meir & Maharat in Israel (unpublished data, Direct submission;2006) (Najafi et al, 2015). This isolate was known as a nephropathogenic IBV strain.…”

“…Numerous genotypes have been detected, some of which have quickly disappeared while others have caused major worldwide disease with economic relevance. Genotyping of IBV strains isolated in Iran showed seven distinct phylogenetic groups (Mass, 793/B like, IS/1494 like, IS/720-like, QX-like, IR-1, and IR-2) based on analysis of mainly HVRs of the S1 gene (Najafi et al, 2014(Najafi et al, -2015Hosseini et al, 2015). In spite of the use of different vaccines (Mass & 793/B type) in poultry farms in Iran, outbreaks have been occurred with high mortality.…”

Genotyping of Infectious Bronchitis Viruses in the East of Iran, 2015

“…Later, several Iranian researchers identified the 793/B serotype, which turned out to be one of the most predominant types of IBV circulating in the country (6). Genotyping of IBV strains isolated in Iran were classified into seven distinct phylogenetic groups (Mass, /B like, IS/1494 like, IS/720-like, QX-like, IR-1, and IR-2) based on analysis of mainly HVRs of the S1 glycoprotein gene (7,8). The aim this study was determination prevalence rate of IBV in the respiratory complex in the East of Iran and genotyping of positive samples.…”

Pathogenicity characteristics of an Iranian variant-2 (IS-1494) like infectious bronchitis virus in experimentally infected SPF chickens

“…In an epidemiology study of IBV between the years 2010-2014, seven distinct genotypes of Mass, 793/B, IS720, variant-2, QX, IR-I, and IR-II were identified (Hosseini et al, 2015). In years 2014-2015 genotypes variant-2, 4/91, IS/720, QX, IR-1 and Mass were isolated from broiler farms (Najafi et al, 2015). It was suggested in an experimental histological study that 793/B may be a nephropathogenic virus (Mahdavi et al, 2007;Boroomand et al, 2012).…”

“…New IBV genotypes including IS720, variant-2, QX, IR-I, and IR-II were detected in a molecular surveillance performed during 2010-2014 (Hosseini et al, 2015). Najafi et al (2015) isolated and characterized variant-2, QX, IS720, IR-I, 793/B, and Mass genotypes from tissue samples collected from Iranian broiler farms between the years 2014-2015. There is no information about the pathogenic aspects of these new variants.…”