Infectious bronchitis: 80 years of control efforts to combat a Coronavirus infection in poultry

Abstract

Infectious bronchitis (IB) is the most important Coronavirus infection in poultry. The IB virus (IBV) spreads rapidly in the affected flocks, and although airborne-spread is the principle route of transmission, contact also plays an important epidemiological role. This Gammacoronavirus infects susceptible chickens at all age groups. It affects not only the respiratory tract, but may also affect the urogenital and possibly to some extent the intestinal tract, depending on the strain characteristics. Besides strict biosecurity measures, vaccination is the most important strategy to control clinical disease. Vaccines, mainly live attenuated vaccines, have been used for almost 80 years. The high mutation and recombination rates and the frequent emergence of new virus variants in association with poor cross-protection, provide a continuous pressure to develop new vaccine candidates and strategies. Therefore, IB is a disease chickens will continue to be challenged with, and eradiation seems to be unrealistic at this point. The availability of advanced molecular techniques is currently opening up new opportunities to develop new generation vaccines and respond to newly emerging strains more quickly compared to traditional approaches. It is important that these new vaccine candidates stimulate the necessary immune mechanisms to provide protection at the main virus entrance site, the respiratory tract. Therefore, they should induce mucosal immunity including humoral as well as cell mediated reactions. The practicability for mass vaccination has to be ensured to be able to use these new vaccines in poultry production.

Keywords

• chicken
• respiratory disease
• false-layer
• vaccination
• mutations