Author/Authors :
Najafi، Hamideh نويسنده Faculty of Veterinary Medicine,Department of Microbiology and Immunology,University of Tehran,Tehran,Iran , , Ghalyanchi Langeroudi، Arash نويسنده Faculty of Veterinary Medicine,Department of Microbiology and Immunology,University of Tehran,Tehran,Iran , , Hashemzadeh، Masoud نويسنده Department of Research and Production of Poultry Viral Vaccine,Razi Vaccine and Serum Research Institute,Karaj,Iran , , Karimi، Vahid نويسنده Faculty of Veterinary Medicine,Department of Poultry Diseases,University of Tehran,Tehran,Iran , , Madadgar، Omid نويسنده Faculty of Veterinary Medicine,Department of Microbiology and Immunology,University of Tehran,Tehran,Iran , , Khaltabadi Farahani، Reza نويسنده Iranian veterinary Organization,Tehran,Iran , , Ghafouri، Ali نويسنده Iranian veterinary Organization,Tehran,Iran , , Maghsoudloo، Hossein نويسنده Iranian veterinary Organization,Tehran,Iran , , Seifouri، Parvaneh نويسنده Iranian veterinary Organization,Tehran,Iran , , Madhi، Ali نويسنده Faculty of Veterinary Medicine,Department of Microbiology and Immunology,University of Tehran,Tehran,Iran ,
Abstract :
Avian infectious bronchitis (IB) is a major cause of economic losses in poultry industry. The IB virus primarily affects respiratory tract, but various strains differ in their tropism for other target organs such as kidney and alimentary tract. The objective of this study was to estimate the pathogenicity of Iranian IBV variant (IR-1), which is limited exclusively to Iran. Specific pathogen free chicks were inoculated intranasally. Sera, fecal swabs and different tissue samples were collected on different days post infection (DPI). Clinical signs, gross pathology and histological changes were recorded. The viral load was quantified in the RNA extractions from different tissue samples using real-time PCR. Anti-IBV antibodies were detected in serum samples. The IgG antibody were found on 21 and 28 DPI. Severe histological lesions were observed in the trachea and lung while the lesions in kidney were appeared to be milder. Viral RNA was detected in all tested tissues from 1 DPI to the last day of the experiment. The highest viral load was measured in the trachea and feces on 1st and 5th DPI, respectively. It can be concluded the IR-1 had broad tropism for respiratory tract, digestive system, and renal tissue, reflecting its epitheliotropic nature, but it caused the most severe lesions in the respiratory tract. This was the first pathogenicity study of Iranian IR-1 IBV. Further knowledge of IBV pathogenesis provides the groundwork to inform more effective prevention practices.
