Molecular evidence of very virulent infectious bursal disease viruses in chickens in Ethiopia.
Infectious bursal disease virus (IBDV) is an important immunosuppressive pathogen of chickens worldwide. The introduction and evolution of IBDV in most African countries, especially in Ethiopia, remains unclear. We have investigated IBDV isolates obtained from commercial broilers, indigenous chickens, and pullets. The hypervariable region of the virus protein (VP) 2 and the 5' two-thirds of VP1 of 11 IBDV isolates were characterized by RT-PCR and further sequencing. All isolates were identified as very virulent (vv) IBDV based on the predicted amino acid (aa) sequences of the VP2 protein. Interestingly, the sequence analysis of the 5' two-thirds of VP1 indicated that the Ethiopian IBDV strains have aa residues typical for vvIBDV and for attenuated IBDV strains. Among all IBDV strains included in this study for phylogenetic comparison of VP2 nucleotide sequences, Ethiopian strains form a cluster within the vvIBDV lineage. We have also shown that Ethiopian IBDV strains have mutations in the VP1 region. Their roles in IBDV virulence may require further in vivo studies. As depicted in this study, the nucleotide and aa sequence analysis of VP1 in addition to VP2 is necessary to obtain a clear picture of the molecular evolution of IBDV.
Clinic for Poultry, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany.
Tamiru
T
Negash
Esayas
E
Gelaye
Henning
H
Petersen
Beatrice
B
Grummer
Silke
S
Rautenschlein
D000818:Animals; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D002645:Chickens; D005002:Ethiopia / Q000453:epidemiology; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D007243:Infectious bursal disease virus / Q000235:genetics / Q000472:pathogenicity*; D017720:Molecular Epidemiology; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D015678:Viral Structural Proteins / Q000235:genetics / Q000378:metabolism; D014774:Virulence
C107669:VP1 protein, infectious bursal disease virus; C082513:VP2 protein, infectious bursal disease virus; D015678:Viral Structural Proteins