Infectious bronchitis (IB) in broilers is an acute, highly contagious viral disease caused by the infectious bronchitis virus (IBV), an avian coronavirus that affects the respiratory tract, kidneys, and sometimes the intestinal and reproductive systems. It is one of the most economically important respiratory diseases in global broiler production due to its rapid spread, high morbidity, and impact on performance. In breeders and layers it may cause acute respiratory disease, drop in egg production and egg deformations.