Lessons Learnt on Infectious Bronchitis Virus Lineage GI-23

• Published in: Avian pathology pp. 1 - 13
• Main Authors: Finger, Avner, Ashash, Udi, Goldenberg, Dana, Raviv, Ziv
• Format: Journal Article
• Language: English
• Published: England 16.09.2024
• Subjects: Variant 2-like strains; Variant 2; Infectious Bronchitis; Lineage GI-23; Infectious Bronchitis Virus
• ISSN: 0307-9457; 1465-3338; 1465-3338
• DOI: 10.1080/03079457.2024.2398030

(IBV) is the first Coronavirus discovered in the world in the early 1930s and despite decades of extensive immunoprophylaxis efforts, it remains a major health concern to poultry producers worldwide. Rapid evolution due to large poultry population sizes coupled with high mutation and recombination events and the reliance of the antiviral immune response on specific antibodies against the epitopes of the S1 glycoprotein, render the control of IBV extremely challenging. The numerous and rapidly evolving genetic and antigenic IBV types are currently classified based on the whole S1 gene sequence, into 36 lineages clustered in 8 genotypes. Most lineages (29) are grouped in Genotype I (GI). "Variant 2" ( ) is the prototype strain of lineage GI-23 and since this lineage emergence during the mid-1990s in the Middle East, it has evolved into numerous genetically related strains and disseminated to 5 continents. The hallmarks of IBV Variant 2-like strain infections are high virulence and remarkable nephrotropism and nephropathogenicity, however the molecular mechanisms of these traits remain to be elucidated. Limited protection from previously utilized vaccine strains and accumulated losses to poultry producers have urged the development and implementation of homologous Variant 2-like vaccine strains. The latest Avian Coronavirus biology with specific emphasis on the cumulative knowledge about IBV "Variant 2" and related strains' emergence, characteristics and control are reviewed.