Avian infectious bronchitis: A review

Avian infectious bronchitis (IB) is a highly contagious and acute disease of chickens caused by avian infectious bronchitis virus (IBV) belonging to family Coronaviridae. The virus causes respiratory disease, reduced production performances, nephrosis and irreparable damage to oviduct leading to production of abnormal eggs. Immunization programmes now seem to be ineffective due to the extreme genetic variations of IBV. Hence, an accurate and rapid serotype determination is an important factor in controlling IBV. Effective diagnostic tools are also needed to differentially diagnose IB infections in field and to identify different serotypes and variants. Ideal management for preventing IB in birds includes timely immunization with live or inactivated vaccines containing circulating strains and strict isolation of the infected birds. Good management and hygienic practices in poultry units can control the spread of IB among flocks to a great extent. The concept of DNA immunization with spike protein gene has revolutionized the concept of IB immunoprophylaxis as it has been found to elicit sufficient immune response. Molecular biology based detection and control strategies have to be developed along with the upgradation of conventional techniques to tackle the growing threat posed by this pathogen so that the disease can be effectively controlled in the years to come.