Epidemiology of Avian Infectious Bronchitis Virus Genotypes in Iran (2010–2014)

Abstract

Infectious bronchitis virus (IBV) in vaccinated chicken flocks continues to cause enormous economic losses to the poultry industry in Iran. A molecular surveillance of IBV genotypes involved in outbreaks of disease was performed. Specimens of trachea, kidney, and cecal tonsil were collected from 250 suspected flocks (more than 2500 samples) and identified between 2010 and 2014. Partial spike glycoprotein gene sequences revealed seven distinct genotypes, including Mass, 793/B, IS720, Variant 2, QX, IR-I, and IR-II, to be circulating in the chicken farms. The majority of flocks (67.6%) experienced infection with an IBV variant unrelated to the vaccine strains. These variants displayed homologies ranging from 54.1% to 78.5% and from 53% to 86% with H120 and 4/91, respectively. These findings reveal the existence of IBV variants genetically different from the vaccine strains currently in use and explain the outbreaks of disease observed in the field. The current work constitutes the first comprehensive survey of IBV in Iran and emphasizes the need for continuous monitoring and rethinking of current preventative measures.

Phylogenetic analysis and full-length characterization of S1 gene of IS-1494 (Variant 2) like infectious bronchitis virus isolates, Iran, 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. The presence of Variant 2 viruses (IS/1494/06 like) in Iranian commercial flocks have been demonstrated (Hosseini et al, 2015). The isolation of IS/1494/06, one of the Israeli Variant 2 isolates, and information on its S1 gene sequence in GenBank (Accession number: EU780077) has first been reported by Meier & Maher from Israel (Meir et al, 2004).…”

“…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 September 1996, an outbreak of disease, characterized mainly by swelling of the stomach, occurred in chicken flocks in Qingdao, China, designated QX IBV (Yu- (Hashemzadeh et al, 2013;Seyfi Abad Shapouri et al, 2004;Shoushtari et al, 2008). 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).…”

“…Until recently, Massachusetts (Mass) and 793/B were the only IBV genotypes identified in Iran. 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.…”