Occurrence: Worldwide.   Species affected: All.   Age affected: All, young are most susceptible.

Causes: Infectious bronchitis virus is a coronavirus, and is the most contagious viral respiratory disease in poultry.

Effects: Sneezing and watery eyes are seen early on, followed by depression, coughing and nasal discharge. Producing birds exhibit drop in egg production or weight gain. Eggs have poor shell quality and watery albumin. Layers also have ruffled feathers and wet droppings. Tracheal rales, gasping and urate diarrhoea are also seen.

Infectious bronchitis is an acute to chronic respiratory disease of all birds of all ages, although young birds are most susceptible. It is caused by a coronavirus.

Very contagious and spreads rapidly by aerosol. Contaminated faeces, litter and fomites spread the virus.

It is one of the most contagious viral respiratory diseases in poultry.

Sneezing and watery eyes are seen early on, followed by depression, coughing and nasal discharge.

Poor egg shell quality, watery albumen, ruffled feathers and wet droppings are seen in laying birds. A drop in egg production and weight gain, tracheal rales, gaping and urate diarrhoea are also seen.

Exudate in trachea, nasal trubinates, air sacs thickened or frothy and pneumonia can be seen. In young birds misshapen (nonpatent and hypoglandular) ova and oviduct, and yolk in abdominal cavity. Occasionally swollen pale kidneys with urates are found.

Virus neutralisation, HI or ELISA test for measuring antibody are helpful. Virus isolation in embryos or chicken kidney cell cultures is necessary for a definitive diagnosis. Curling, stunting and death of embryos can be seen in inoculated embryonating eggs. Respiratory signs and lesions with kidney lesions give a presumptive diagnosis.

Vaccinate birds with multiple serotypes (depending on region) for broad spectrum protection. Internationally, vaccines of the Massachussetts type are generally used (H20 or cloned type Ma5), preferably by spray or eye drop. Inactivated vaccine can be given for breeders or layers at 18-22 weeks of age by injection.

Sanitation, hygiene and biosecurity are also important.

Antibiotics for killing secondary bacterial invaders in feed or water are helpful if signs of secondary infections are observed.

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