Infectious bursal disease virus (IBDV) infects both domestic and wild birds, and targets the immune system tissues. This results in immunosuppression, leaving infected chickens open to other infections such as E. coli, Salmonella and Mycoplasma. IBDV belongs to the family Birnaviridae, genus Avibirnavirus; two serotypes exist but only serotype 1 is pathogenic. The virus is non-enveloped and has a capsid that contains a double stranded RNA genome that is split into two segments.
IBDV causes infectious bursal disease (also known as Gumboro disease) in poultry. It's genome is split into two segments which can then rearrange (reassort). The very virulent strains of IBDV (vvIBDV) have mutations that allow the virus to replicate faster and cause more severe disease.
- Depression and ruffling of feathers
- Lack of appetite
- Unsteady gate
- Reluctance to rise
- Diarrhoea (sometimes bloody)
- Increased rate of infection with secondary diseases
IBDV can be spread via direct contact or by contaminated feed, water and faeces. The virus is very hardy and can persist in poultry house environments for several months or longer even if infected chickens are removed.
The virus is endemic in many parts of the world.
Impact for Society – what are we doing?
IBDV infection can lead to significant morbidity and mortality, and birds that recover may have impaired immune responses, increasing their susceptibility to other infections and reducing their ability to mount effective immune responses in vaccination programmes.
Current research projects are looking at the host factors involved in the viruses life cycle, determining the viral factors that affect IBDV virulence and their function, and evaluation of novel vaccines against IBDV.