The Infectious Bronchitis virus (IBV) is a variety of Coronavirus that targets not only the respiratory tract but also the urogenital tract of young chickens and broiler chickens. Prevention can involve a series of live and/or killed vaccines or a live vaccine every other month throughout the lay cycle. Progeny can be vaccinated at 2 weeks regardless of whether the parental antibody titers are at hatching. Even chicks that had high maternal antibody at 1-day of age will be susceptible.
Spread to other birds is rapid, and morbidity may be nearly 100%. The nature and severity of the disease are influenced by the age and immune status of the flock and virulence of the causal strain. The incubation period is relatively short and can spread through populations quickly. The IB virus is spread via airborne particles, through contaminated organic material, drinking water and equipment. Control is best achieved by improved biosafety and vaccination.
Young chickens may cough, sneeze, and have tracheal rales for days, and wet eyes and dyspnea may be seen. In broiler chickens, IBV infection is a major cause of reduced growth rate and condemnation of meat at processing. In layers, egg production may drop 5-50%, and eggs are often misshapen, thin-shelled, and contain watery albumen.