Absence of Emerging GVIII IBV Genotypes IB۸۰ and D۲۸۶۰ in Iranian Poultry: Molecular Surveillance From ۲۰۲۲–۲۰۲۵

Introduction: Infectious bronchitis virus (IBV), a highly contagious pathogen within the Gammacoronavirus genus, significantly impacts global poultry health and productivity through respiratory disease, reduced weight gain, and impaired egg production. The emergence of genotype VIII (GVIII) strains, particularly IB۸۰ and D۲۸۶۰, in Europe and parts of Asia has raised international concern due to their potential for immune evasion and distinct antigenicity. This study aimed to assess the presence of these GVIII variants in Iranian broiler and broiler breeder flocks through molecular surveillance conducted between ۲۰۲۲ and ۲۰۲۵.Materials & Methods: A total of ۲۰۰ tracheal and pulmonary tissue samples were collected from chickens exhibiting clinical respiratory signs across multiple provinces in Iran—۱۴۰ from broilers and ۶۰ from breeders. RNA was extracted and subjected to reverse transcription– polymerase chain reaction (RT-PCR) using strain-specific primers targeting the spike gene of IB۸۰ and D۲۸۶۰.Results: No positive amplifications were observed in any of the samples, indicating that these GVIII strains were either absent or present below the detection threshold of the assay (~۱۰۰ RNA copies/μL). Positive and negative controls validated the assay performance.Conclusion: These findings suggest a continued dominance of established IBV lineages in Iran, including Variant ۲ (IS/۱۴۹۴-like), ۷۹۳/B, and QX genotypes, with no evidence of GVIII incursion in the sampled populations. The apparent absence of IB۸۰ and D۲۸۶۰ may reflect geographical constraints, host-specific tropism, or competitive exclusion by dominant genotypes. However, continued surveillance, especially in layer flocks and border regions, remains essential for the early detection of emerging IBV threats. This study contributes vital baseline data to regional and global IBV monitoring efforts.

کلیدواژه ها:

Breeders ، broilers ، D۲۸۶۰ ، IB۸۰ ، IBV genotype VIII ، Infectious bronchitis virus (IBV) ، Iran ، molecular surveillance