Molecular characterization of infectious bronchitis viruses isolated from broiler and layer chicken farms in Egypt during 2012

Abstract

One of the major problems of avian infectious bronchitis virus (IBV) is the frequent emergence of new variants. In the present study 205 tracheal swabs and organs were collected from broilers and layers chicken farms during January to August 2012 from 19 governorates all over Egypt. The chickens demonstrated respiratory signs and mortality. Out of the examined samples, 130 of which (about 64%) of suspected farms were positive for IBV with real time RT-PCR. 13 IBV-positive samples were selected for further isolation and characterization. Isolation in specific pathogen free (SPF) embryos was carried out after studies three blind successive passages and the hypervariable region of spike protein1 (SP1) was amplified by RT-PCR and sequenced to study the genetic diversity between the isolated viruses. Phylogenetic analysis of the obtained sequences of 13 isolates compared with other IBV strains from the Middle East and worldwide reveled that 11 out of the 13 isolates had close relationship the Israeli variants (IS/885 and IS/1494/06) with nucleotide homology reached up to 89.9% and 82.3%, respectively. Only two isolates had close relationship with CR/88121 and 4/91 viruses with identities of 95% and 96%, respectively. This study indicates existence of two variant groups of IBV circulating in Egypt during 2012. Group I was Abbreviations: IBV, infectious bronchitis virus; SP, spike; HVR, hypervariable region; RT-PCR, real-time reverse transcription-polymerase chain reaction. * Corresponding author. Tel.: +20 01007274973/2 28711575; fax: +20 2 33370957.

New real time and conventional RT-PCRs for updated molecular diagnosis of infectious bronchitis virus infection (IBV) in chickens in Egypt associated with frequent co-infections with avian influenza and Newcastle Disease viruses

“…The current situation of IB infections in Egypt seems to be the result of a continuing evolution starting with infections caused by Egyptian variant I since 2001, Egyptian variant II since 2011, and Mass-like strains since 2006 (Abdel-Moneim et al, 2012;Selim et al, 2013). Tracheal ciliostasis is one of the early and characteristic pathogenetic sequelae of IBV infection (Cook et al, 1976).…”

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

“…In May 2012, the virus designated IBV/chicken/Egypt/VRLCU154/2012, isolated from tracheal swabs from a vaccinated broiler flock and it was in close relationship with the IBV isolate IS/1494/06 (Hussein et al, 2014). Another study of IBVs isolated from broiler and layer chicken farms in Egypt revealed that 11 out of 13 isolates had a close relationship with Israeli variants (IS/885 and IS/1494/06), with nucleotide homology reaching up to 89.9% and 82.3%, respectively (Selim et al, 2013). In Libya, 12 IBV strains obtained from broiler flocks with respiratory disease and high mortality were differentiated by sequencing of the S1 gene.…”

First characterization of a Middle-East GI-23 lineage (Var2-like) of infectious bronchitis virus in Europe

“…Molecular monitoring of IBV strains circulating in Iran revealed that most detected strains belonged to IS/720 and Var2 (both GI-23), which were responsible for 18.4% and 17.2% of clinical cases of IB, respectively (Hosseini et al, 2015). In Egypt, this IBV lineage has been circulating since 2010 and by 2012 has dominated among other strains (Hussein et al, 2014;Selim et al, 2013;Zanaty et al, 2016). In 2011 and 2012 the GI-23 strains has been identified in Turkey and Libya, respectively (Awad et al, 2014;Kahya et al, 2013;Yilmaz et al, 2016).…”

“…Later on, the presence of IBV GI-23 was found in Saudi Arabia, Kuwait, Bahrain, Armenia, and since 2015 also in Russia, Lithuania and Ukraine (personal information from Ashash U., Israel). The IBV GI-23 lineage was detected in unvaccinated and vaccinated broilers, layers and broiler breeders and caused respiratory system disease, kidney damage and drop in egg production (Hussein et al, 2014;Kahya et al, 2013;Selim et al, 2013). Intensive international trade, uncontrolled movement of people and animals as well as of wild birds across the borders of the Middle Eastern countries were suspected as the cause of the spread of the GI-23 lineage (Domanska-Blicharz et al, 2014;Hussein et al, 2014;Kahya et al, 2013).…”