Experimental study on histopathologic changes and tissue tropism of 793/B serotype of Infectious bronchitis in broiler chickens
Subject Areas : Journal of Comparative Pathobiology
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Keywords: Histopathology, Dissemination, Infectious Bronchitis Virus, 793/B serotype,
Abstract :
Avian infectious bronchitis is an important pathogen in poultry industry, which commonly induces respiratory diseases, with tropism to other organs based on strains. The aim of this study was to investigate the tissue lesions and tropism of avian infectious bronchitis virus strain 793/B in experimentally infected broiler chickens. In this study, tissue lesions and dissemination of 793/B serotypes of IBV in different organs of broiler chickens was studied. Ninety-one-day-old chicks were divided randomly into two groups (45chicks per group). At the age of 10 days old the chicks in group1 were inoculated intraocularly with 103EID50 of the 793/B isolate, and group2 was kept as control. The samples from various tissues were collected at 2 till 16 days’ post-inoculation (PI) for virus detection and histopathology. The chicks of infected group exhibited depression at 2 to 8 days PI. The IBV virus was detected in the cloaca and kidney through the study, in trachea virus was detected on days 2 to 8 and in lung samples on 2-6 days PI. In trachea virus causes deciliation, epithelium hyperplasia, mononuclear and heterophils infiltration. Lung tissue was hyperemic, hemorrhagic, and edema and fibrinous exudate with mononuclear infiltrations was seen. In kidney tissue hyperemia and hemorrhage with necrosis of tubules was recorded. The results of this study indicated that the 793/B serotype of IBV cannot cause mortality, clinical signs or gross lesions in infected chickens.