The emergence, evolution and spread of infectious bronchitis virus genotype GI-23

Abstract

Avian infectious bronchitis is a contagious viral disease, caused by avian infectious bronchitis virus (IBV), that leads to severe losses in the poultry industry all over the world. Since the 1950s, IBV has circulated in the Middle East and North Africa, and no tangible evidence has shown any effects of measures taken to control its spread or evolution. Furthermore, new IBV variants are continually discovered. Although several genetic studies on IBV have been conducted, many IBV strains from this region have either been misclassified or remain unclassified. The genotype 23 (GI-23) variant emerged and has prevailed in the Middle East by continuously evolving through inter-and/or intra-genotypic recombination. The GI-23 genotype is currently enzootic throughout Europe and Asia. Although many studies of protection against the circulating strains have been conducted, they have not been standardized according to regulatory requirements. In this review, we provide an overview of the evolution and genetic diversity of IBV genotypes and a genetic classification of IBV strains, with a focus on the GI-23 genotype. The high prevalence of IBV GI-23 strains necessitates the adoption of vaccination schemes using GI-23-based vaccines.

Phylodynamic and Recombination Analyses of Avian Infectious Bronchitis GI-23 Reveal a Widespread Recombinant Cluster and New Among-Countries Linkages

“…IBV has been demonstrated to be a virus with a remarkable evolutionary potential, which has led to the emergence of several genotypes and lineages, some of those featured by outstanding epidemiological success. Among these lineages, the GI-23 was initially discovered in Middle East countries and has been more recently identified out of this area and reported in the Far East, Africa, and Europe [ 17 , 18 , 29 , 30 , 31 , 32 ].…”

“…of Animal Medicine, Production and Health (Padua University, Padua, Italy). IBV diagnosis and preliminary characterization were performed based on the amplification and sequencing of the S1 hypervariable region 3 (HVR3) using the primer pair XCE1-2 [ 18 ]. Strains classified as GI-23 were confirmed and further characterized using in-house designed primer pairs allowing the amplification and sequencing of the whole S1 region in two overlapping PCRs (i.e., PCR1: S1_F 5′-GGAACGGTAAGGTGTTAGTT-3′ and S1Inner_R 5′-TTAGGCGAGGCATTACTTACTTAC-3′; PCR2: S1Inner_F 5′-GTGTGATAATTCACCAAGAGG-3′ and S1_R 5′-CATTCAGTAAAGGTGCCACAA-3′).…”

“…The GI-23 is currently one of the most important and widespread lineages. Firstly detected in the Middle East [ 16 , 17 ] two decades ago, it then spread to other geographical regions, including Turkey (2010), Armenia (2012), Azerbaijan (2012), Lithuania (2012), Nigeria (2013), Kazakhstan (2015), Afghanistan (2016), Romania (2016), Poland (2016), Russia (2016), China (2018), and Germany (2019) as reviewed in Houta et al [ 18 ].…”

Diversity of gammacoronaviruses and deltacoronaviruses in wild birds and poultry in Russia

“…These three genotypes belong to AvCov/AvCov9203 group of subgenus Igacovirus. Coronaviruses of the Massachusetts lineage (first reported in USA) and the 793/B (Europe origin) genotypes are not only found worldwide, but they are the most well-characterised and important IBV genotypes due to their agricultural significance 21,30 . Genotype 793/B emerged in the UK and France in the 1990s, and became prevalent in Europe and many other parts of the world 31 .…”

Detection and genetic characterization of novel infectious bronchitis viruses from recent outbreaks in broiler and layer chicken flocks in southern China, 2021

“…IBV can be transmitted through the respiratory and fecal-oral routes and cause damage to the respiratory, reproductive, and urinary systems. Therefore, the poultry exhibits symptoms such as difficulty breathing, sneezing, rales in the trachea, lethargy, nephritis, fallopian tube disease, reduced egg production, and even death ( Houta et al, 2021 ). Although chicken flocks of all ages are susceptible hosts, the symptoms of infection in chickens at different ages are not always the same ( Cavanagh, 2007 ).…”