Infectious bronchitis virus
Infectious bronchitis virus (IBV) is a highly infectious, single-stranded, enveloped, RNA virus belonging to the Coronavirus family. IBV causes infectious bronchitis (IB) in chickens, targeting the respiratory and urogenital tract. Infection initially takes place via the respiratory tract, where it replicates and produces lesions in the epithelial cells. Depending on the virus strain, it may also cause damage to the kidney, gonads (oviduct, testes), and alimentary tract (esophagus, proventriculus, duodenum, jejunum, bursa of Fabricius, cecal tonsils, rectum, and cloaca).
Control: At present, for the commercial poultry industry, live attenuated vaccines are widely used for the prevention and control of IB. However, due to extensive genetic diversity of IBV strains, the vaccines are becoming increasingly inefficient, with poor cross-protection effects among different serotypes of vaccines.
Transmission: IBV is transmitted to chickens through inhalation or direct contact with infected chickens, contaminated equipment, environment, human handlers or fomites.
Survival in the environment: Outdoors, IBV can survive up to 12 days in the spring and 56 days in the winter.
Incubation period: IBV has a short incubation period and the virus spreads rapidly in the flock. Susceptible birds develop signs within 24-48 hours.
Treatment: Although IBV is highly transmissible, most birds will recover with supportive treatment.
Vaccine: Infectious bronchitis is often combined with Newcastle in a single vaccine. It can be given at the hatchery or at 10–35 days of age. It is a modified live-virus vaccine, typically containing bronchitis virus of the Massachusetts serotype. Vaccines are only effective if they contain the right serotype of virus for a given area. Do not vaccinate during an outbreak.
Disinfectants: IBV is easily killed by common household disinfectants as long as it is not in organic matter.
- Saif, Y. M Diseases of poultry. John Wiley & Sons (2009)