Absence of Emerging GVIII IBV Genotypes IB80 and D2860 in Iranian poultry: Molecular Surveillance from 2022–2025

Articles in Press

Document Type : Original Articles

Authors

1 Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

2 Department of Avian Diseases, Faculty of Veterinary Medicine, Karaj Branch, Islamic Azad University, Karaj, Alborz

3 agriculture and veterinary group, faculty of encyclopedia, IHCS, Tehran, Iran

10.22092/ari.2025.370309.3776

Abstract

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 IB80 and D2860, 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 2022 and 2025. A total of 200 tracheal and pulmonary tissue samples were collected from chickens exhibiting clinical respiratory signs across multiple provinces in Iran—140 from broilers and 60 from breeders. RNA was extracted and subjected to RT-PCR using strain-specific primers targeting the spike gene of IB80 and D2860. 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 (~100 RNA copies/μL). Positive and negative controls validated assay performance. These findings suggest a continued dominance of established IBV lineages in Iran, including Variant 2 (IS/1494-like), 793/B, and QX genotypes, with no evidence of GVIII incursion in the sampled populations. The apparent absence of IB80 and D2860 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 early detection of emerging IBV threats. This study contributes vital baseline data to regional and global IBV monitoring efforts.

Keywords

Archives of Razi Institute

Articles in Press, Accepted Manuscript
Available Online from 19 October 2025

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