Molecular and Histopathological Detection of Newcastle Disease, Avian Influenza (H9N2), and Infectious Bronchitis viruses in backyard chickens around Ahvaz City

Boroomand, Zahra; Ghanei, Ali; Rezaie, Anahita; Farokhian, Setayesh

doi:10.22092/ari.2026.371622.3975

Molecular and Histopathological Detection of Newcastle Disease, Avian Influenza (H9N2), and Infectious Bronchitis viruses in backyard chickens around Ahvaz City

Articles in Press

Document Type : Original Articles

Authors

¹ Department of Livestock, Poultry, and Aquatic Animal Health, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran

² Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz

10.22092/ari.2026.371622.3975

Abstract

Introduction: Avian influenza virus subtype H9N2, Newcastle disease virus, and infectious bronchitis virus are among the major respiratory pathogens affecting chickens. Backyard chickens can serve as reservoirs for these diseases in industrial poultry. The present study aims to evaluate the molecular and histopathological detection of H9N2, ND, and IB viruses in backyard chickens around Ahvaz city.
Material and Methods: 54 backyard chickens were purchased; after clinical examination, the birds were euthanized and necropsied. Following necropsy, specimens of the trachea, lung, kidney, cecum, and cecal tonsils were obtained for molecular detection and histopathological evaluation. These birds showed thinness and ruffled feathers.
Results: The results showed that in the molecular test, 51% of the birds were positive for H9N2, 50% for ND virus, and 64% for IB virus. 77% of the birds were infected with one of the three viruses in the molecular analysis. Also, simultaneous infections with H9N2 and ND viruses were observed in 9%, H9 and IB viruses in 9%, ND and IB viruses in 4%, and all three viruses in 27% of birds. In the microscopic examination of tissue sections, meningoencephalitis and PVC, interstitial lymphocytic nephritis, necrosis of the epithelial cells of urinary tubes, glomerulonephritis, lymphocytic tracheitis, interstitial lymphocytic pneumonia, bronchopneumonia, hyperplasia of lymphoid tissue around the bronchi, and enteritis were observed.
Discussion: The results indicate widespread presence of respiratory viruses in backyard chicken. Considering that these birds had not received any vaccines according to their history, the molecularly positive samples indicate exposure to the viruses.
Conclusion: It is concluded that backyard chickens serve as an essential reservoir of viruses and can contribute to their transmission to industrial poultry.

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