Genus: Avibirnavirus

Genus: Avibirnavirus

Distinguishing features

Viruses in the genus infect only birds. 


See discussion under family description.

Genome organization and replication

See discussion under family description.


Infectious bursal disease virus (IBDV) causes an immunosuppressive disease in chickens by destruction of B lymphocytes in the bursa of Fabricius. Apoptosis has also been observed in this and other lymphoid organs. VP5 inhibits apoptosis at the early stage of viral infection in chicken embryonic fibroblast cells, whereas VP2 induces apoptosis in transfected mammalian cells. The latter finding correlates with evidence of apoptosis and B cell death in chickens infected with IBDV. The rapid depletion of B cells in the bursa of Fabricius leads to immunosuppression and increased susceptibility to other infections and diseases. The virus is highly contagious and is of major importance to the poultry industry worldwide. Two serotypes (1 and 2) of IBDV have been identified by cross-neutralization assays. Serotype 1 strains are pathogenic in chickens, whereas serotype 2 strains are nonpathogenic.

Species demarcation criteria

Not applicable. 

Member species

Exemplar isolate of the species
SpeciesVirus nameIsolateAccession numberRefSeq numberAvailable sequenceVirus Abbrev.
Infectious bursal disease virusinfectious bursal disease virusP2SegA: X84034; SegB: X84035Complete genomeIBDV
Infectious bursal disease virusinfectious bursal disease virusUK661SegA: X92760; SegB: X92761Complete genomeIBDV

Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.