Designing a new primer based on the E gene for more accurate molecular detection of avian infectious bronchitis virus

Ziafati Kafi, Zahra; Ghorani, Mohammad Reza; Ghalyanchilangeroudi, Arash; Sarmadi, Soroush

doi:10.22092/ari.2026.370509.3815

Designing a new primer based on the E gene for more accurate molecular detection of avian infectious bronchitis virus

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 Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran

10.22092/ari.2026.370509.3815

Abstract

Background:
Infectious bronchitis (IB) is a highly contagious disease of chickens caused by the infectious bronchitis virus (IBV), affecting the respiratory and urogenital systems and leading to significant economic losses due to decreased egg quality and increased susceptibility to secondary infections. Early and reliable molecular diagnosis of IBV is essential for effective disease control. Although conserved genomic regions such as the N gene and untranslated regions (UTRs) are commonly targeted in diagnostic assays, alternative conserved targets may improve detection performance.
Materials and Methods:
In this study, a novel primer targeting a conserved region of the E gene of the IBV genome was designed to amplify a 147-bp fragment. Its performance was compared with a previously reported N-gene-based primer. Equal concentrations of viral RNA from four IBV strains (Ma5, Variant 2, QX, and 793/B) were extracted and subjected to RT-PCR using both E- and N-gene primers. Three RNA concentrations (undiluted, 1:10, and 1:100 dilutions) were evaluated to assess detection sensitivity.
Results:
RT-PCR results showed that the E-gene primer successfully detected QX and Ma5 strains at all three concentrations (undiluted, 1:10, and 1:100). The 793/B strain was detected at undiluted and 1:10 dilutions, while Variant 2 was weakly detected only in the undiluted sample. In contrast, the N-gene primer weakly detected only the 793/B strain at undiluted and 1:10 dilutions and failed to detect the other strains at any concentration.
Conclusion:
The newly designed E-gene primer demonstrated superior detection performance compared to the previously used N-gene primer. Targeting conserved regions of the IBV genome, such as the E gene, may enhance the sensitivity and reliability of molecular diagnostic assays. Further optimization and validation studies are recommended to improve IBV detection strategies.

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