Clinical evaluation of SPF chickens infected with 7 93/B serotype of Infectious Bronchitis virus

Avian infectious bronchitis virus (IBV) is one of the most important viral diseases in almost all countries with intensive poultry industry. This disease characterized primarily by respiratory signs, but some IBV serotypes may also cause other signs such as the involvement of intestine and kidney. The aim of this study was to characterize the Clinical signs and gross lesions of 793/B serotype of avian infectious bronchitis virus in experimentally infected SPF chickens. Forty two one-day-old SPF chicks were divided randomly into two groups (21chicks each group). At the age of 12 days old the chicks in group1 were inoculated intra-ocularly with 103EID50 of the 793/B isolate, and the group2 was as control. Chickens in each groups was evaluated from 1 to 14 days post inoculation. The results of this study indicated that the 793/B serotype of IBV cannot cause mortality, and only slight clinical signs such as gasping and depression were seen in infected chickens. Gross lesions indicated this serotype only induces slight lesions in trachea, but in kidney and bursa of fabricius the lesions were severe. These results demonstrated that 793/B serotype cannot cause mortality, sever clinical signs or gross lesions in infected chickens, but its effects on lymphoid tissues should be further studied.