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, Ahvaz, Iran.
10.32598/ARI.81.4.3975
Abstract
Introduction: Avian influenza virus subtype H9N2, Newcastle disease (ND) virus, and infectious bronchitis (IB) virus are among the major respiratory pathogens affecting chickens. Backyard chickens can serve as reservoirs for these diseases and pose a risk to industrial poultry. The present study aims to conduct a molecular and histopathological investigation of H9N2, ND, and IB viruses in backyard chickens around Ahvaz City.
Materials & Methods: Fifty-for backyard chickens were purchased; after clinical examination, the birds were euthanized and necropsied. Following necropsy, specimens of the brain, trachea, lungs, and kidneys were obtained for molecular detection and histopathological evaluation. These birds showed emaciation and ruffled feathers.
Results: Investigation results showed that 51% of the birds were positive for H9N2, 50% for ND virus, and 64% for IB virus. In the molecular analysis, 85% of the birds were infected with at least one of the three viruses. Also, simultaneous infections with H9N2 and ND viruses were observed in 9%, H9N2 and IB viruses in 9%, ND and IB viruses in 4%, and all three viruses in 27% of the birds. In the microscopic examination of tissue sections, meningoencephalitis and privascular cuffing (PVC), interstitial lymphocytic nephritis, necrosis of the epithelial cells of the renal tubes, glomerulonephritis, lymphocytic tracheitis, interstitial lymphocytic pneumonia, bronchopneumonia, hyperplasia of lymphoid tissue around the bronchi, and enteritis were observed.
Conclusion: The results indicated the widespread presence of respiratory viruses in backyard chickens. Considering that these birds had not received any vaccines according to their history, the molecularly positive samples indicate exposure to the viruses. It is concluded that backyard chickens serve as an important reservoir for these viruses and can contribute to their transmission to industrial poultry.
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