Infectious Bursal Disease, IBD, Gumboro

Infectious bursal disease (IBD) or Gumboro disease is a highly contagious disease of young chickens caused by infectious bursal disease virus characterized by immunosuppression and mortality.

Young birds at around 2 to 8 weeks of age that have highly active bursa of Fabricius are more susceptible to the disease.

Birds over 8 weeks are resistant to challenges and will not show clinical signs unless infected by highly virulent strains.

Infection is through oral-fecal route (when the bird ingests contaminated faeces).

Acute disease and death is due to the destructive effect of the virus on the host tissues.

Kidney failure is a common cause of death in affected bird.

If the bird survives, it remains immunocompromised which means it is more susceptible to other diseases.

Clinical signs:

1.    Disease may appear suddenly and spread typically reaches 100%.

2.   Mortality commences on the third day of infection, reaches a peak by day 4, then drops rapidly, and the surviving chickens recover to a state of apparent health after 5 to 7 days.

3.    In the acute form birds are prostrated, debilitated and dehydrated.

4.    They produce a watery diarrhoea and may have swollen vent stained with faeces.

5.    Most of the flock is recumbent and have ruffled feathers.

6.  Mortality rates vary with virulence of the strain involved, the challenge dose, previous immunity, presence of concurrent disease, as well as the flock's ability to mount an effective immune response (from vaccination).

Treatment and Control:

1.  Breeder flocks may be immunised against IBD so that they would transfer protective antibodies to their progenies, such as broiler and pullet chicks.

2. Low-attenuated vaccine strains may cause damage to the bursa of Fabricius and immunosuppression in susceptible chicks.

3.    Biosecurity with adequate restriction to farm visitation and distancing from other flocks.

4.  Post outbreak hygiene measures may not be effective as the virus can survive for long periods in both housing and water.

5.   The virus is sensitive to sodium hydroxide (it is totally inactivated when pH exceeds 12), but it is not affected at pH of 2.

6. The iodinated and chlorinated derivatives, as well as the aldehydes (formaldehyde, glutaraldehyde) are also active.

Prior to cleaning, all insects and pests (e.g. rats and mice) must be eliminated as soon as the farm premises are empty.

Old bedding and dung must be eliminated and composted.

All farm equipment must be disassembled and stored in cleaning rooms located outside the farm buildings.

The buildings, surroundings and farm equipment must be dry-cleaned first, in order to eliminate dust, and then washed using hot water with a detergent.

A second disinfection of the full premises must be performed before the introduction of the chicks.

Feeders must be emptied completely and cleaned.

Under no circumstances may feed remains from previous flocks be reused.

Disinfection is to be undertaken only after all the buildings have been cleaned.

All disinfectants are more active at a temperature above 20°C; however, chlorinated and iodinated disinfectants cannot be heated above 43°C.