Avian Infectious Bronchitis (IB)

 Avian Infectious Bronchitis (IB)
is a contagious disease of birds due to a Coronavirus and causing important economic loss in chicken operations.
■ Distribution:::
IB is distributed worldwide.
■ Susceptible species:::
Chicken
Distribution
IB is distributed worldwide
■ Clinical signs :::
The incubation period is short (1-2 days) and signs usually include:
●● In young animals:
● Gasping, coughing and nasal discharge,
● Wet eyes
● Swollen sinuses,
● Reduction of food consumption and weight gain.
●● In adult:
● Gasping and coughing,
● Drop in production
● Production of misshapen soft-shelled eggs with inferior internal quality is often seen and can be permanent.
The mortality may be as high as 25% in young chicks, nephrogenic strains may cause 60% mortality. Adults usually recover after a few weeks.
■ Diagnosis:::
Lab Diagnosis
● Identification of virus can be done by
● immunofluorescence
● electron microscopy,
● polymerase chain reaction techniques,
● haemagglutination inhibition tests
● enzyme-linked immunosorbent assays (ELISA).
Serological tests are available and include ●virus neutralisation,
● agar gel immunodiffusion,
● haemagglutination inhibition
● ELISA.
■ Post-mortem findings:::
● Accumulation of mucus in the trachea,
Obstruction of nasal passages and sinuses and the air sacs
● Tracheal mucous plugs in dead broilers.
● Reduction of length and weight of reproductive tract
● Nephrogenic strains cause pale and swell kidneys, with large amounts of uric acid crystals.
■ Transmission:::
It can be transmitted by
● aerosols,
●contaminated feed and water,
● contact with animals or material.
Morbidity often reaches 100%.
■ Treatment:::
No specific treatment but supportive treatment is done to prevent secondary infections
■ Control / vaccines :::
● Killed and attenuated lived vaccines are commercially available, it seems that live vaccines protect against a wider range of strains, although they can cause a mild respiratory infection.
● Once introduced IB is difficult to eradicate and require strict isolation of infected premises and slaughtering of flocks.