Avian infectious bronchitis virus (IBV) is a coronavirus which infects chickens, causing the associated disease, infectious bronchitis (IB).
Infectious bronchitis virus is prevalent in all countries with an intensive poultry industry, with the incidence of infection approaching 100% in most locations. It is a highly infectious avian pathogen which affects the respiratory tract, gut, kidney and reproductive systems of chickens.
There is also evidence that IBV can infect other avian species. IBV affects the performance of both meat producing and egg producing chickens and is responsible for substantial economic loss within the poultry industry.
When inhaled, virus will attach to glycoprotein receptors containing sialic acid on ciliated epithelial cells of the respiratory epithelium. Infected chicks are the major source of virus in the environment, however contaminated equipment and material are a potential source for indirect transmission over large distances.
Clinical signs will develop in contact chicks within 36 h and in nearby sheds within one to two days. Coughing and rattling are common, most severe in young, such as broilers, and rapidly spreading in chickens confined or at proximity. Morbidity is 100% in non-vaccinated flocks. Mortality varies according to the virus strain (up to 60% in non-vaccinated flocks).