Detection of infectious bursal disease virus (IBDV) genome in free-living pigeon and guinea fowl in Africa suggests involvement of wild birds in the epidemiology of IBDV

Infectious bursal disease (IBD) virus (IBDV) serotype 1 is the causative agent of IBD, a highly contagious immunosuppressive disease of young chickens. In this study, we examined IBDV infection in apparently healthy 21 guinea fowls and 20 pigeons obtained in Tanzania and Zambia by virus neutralization test (VNT) and reverse transcription polymerase chain reaction (RT-PCR) for the VP2 hypervariable region (VP2-HVR) of IBDV. Two guinea fowls (9.5%) in Tanzania were RT-PCR and VNT positive for IBDV, and 1 pigeon (5%) in Tanzania was RT-PCR positive and VNT negative. Phylogenetic analysis based on the nucleotide sequences of the PCR products indicated that segment A of IBDV detected from one guinea fowl and a pigeon belonged to the very virulent genotype of European/Asian type, while the other IBDV detected from a guinea fowl belonged to the classical genotype. To our knowledge, this is the first report of detection of the IBDV genome in free-living pigeons and guinea fowls. The detection of IBDV from apparently healthy guinea fowls and pigeons elucidates the role of wild birds in the epidemiology of IBDV.