Comprehensive Insights into Infectious Bronchitis Virus in Poultry: Evolution, Immunopathogenesis, and Advances in Modern Vaccine Strategies

Infectious bronchitis virus (IBV) remains a major global threat to poultry production due to its high transmissibility, genetic diversity, and continuous emergence of new variants. This review summarizes the historical development, epidemiology, and molecular characteristics of IBV, with emphasis on its rapid evolution driven by mutation and recombination. The virus exhibits broad tissue tropism affecting respiratory, renal, and reproductive systems, resulting in significant economic losses. Host immune responses, including humoral and cellular immunity, play crucial roles in controlling infection, yet viral immune evasion mechanisms limit long-term protection. Classical vaccines face challenges due to antigenic drift and short-lived immunity. Therefore, modern vaccine strategies such as recombinant vector vaccines, DNA and mRNA platforms, nanoparticle-based systems, and yeast-based delivery approaches have been explored. These novel technologies aim to enhance cross-protection, durability, and mucosal immunity. Continuous surveillance and innovative vaccine development remain essential for effective control of IBV in poultry industries worldwide.