Genome-Wide Evolutionary Dynamics of Avian Infectious Bronchitis Virus in South Korea, 1984-2022

Why It Matters

Whole‑genome insights expose hidden IBV diversity and transmission pathways, prompting more effective control strategies for a virus that threatens global poultry profitability.

Key Takeaways

• Whole-genome analysis reveals new K‑IId variant C3 in 2021‑2022.
• 73.7% recombination events occur in ORF1a/1b non‑structural regions.
• Six cross‑border transmission waves detected between South Korea and China.
• S1‑based classification misses major genomic diversity of IBV.
• Findings support genome‑wide surveillance for improved vaccine design.

Pulse Analysis

Infectious bronchitis virus remains a persistent threat to poultry producers worldwide, costing billions in lost productivity despite routine vaccination. Conventional monitoring relies heavily on the S1 spike gene, a narrow lens that can overlook the virus’s broader genetic shifts. By sequencing entire IBV genomes, researchers can capture the full spectrum of mutations, recombination, and lineage emergence, offering a more accurate picture of viral dynamics and informing risk assessments for the industry.

The South Korean study examined 198 isolates collected over nearly four decades, producing 230 complete genomes for deep analysis. This effort uncovered a previously unknown K‑IId lineage, designated C3, which circulated during 2021‑2022, highlighting how novel variants can arise unnoticed under S1‑centric surveillance. Moreover, 38 recombination events were mapped, with a striking 73.7% localized to the ORF1a and ORF1b non‑structural regions—areas traditionally ignored but now shown to host hypervariable loci that drive IBV evolution.

Beyond the molecular findings, the research traced six discrete transmission waves between South Korea and China, underscoring the virus’s capacity for rapid, cross‑border spread. These insights reinforce the call for coordinated, genome‑wide surveillance networks and suggest that next‑generation vaccines should target conserved elements beyond the S1 protein. For poultry stakeholders, adopting such comprehensive monitoring could reduce outbreak frequency, safeguard supply chains, and ultimately protect the sector’s bottom line.