title: Further evidence for very virulent infectious bursal disease virus in vaccinated chickens in Nigeria.
abstract: Reverse transcription polymerase chain reaction (RT-PCR) and partial sequencing of the VP2 hypervariable region was performed on clinical samples from two infectious bursal disease (IBD) outbreaks in Plateau state, Nigeria. IBD virus RNA was detected in all four bursa of Fabricius samples. Nucleotide sequencing and analysis of the four samples revealed high similarity to previous IBDV sequences from northern and southern Nigeria. The deduced amino acid sequences were compared to reference IBDV strains retrieved from the GenBank; virulence markers A222, I256, and I294 were conserved in both outbreak and reference sequences. Amino acid residue S254 was conserved in the outbreak viruses and previous viruses from northern Nigeria. Phylogenetic analysis revealed that all four viruses were very virulent IBDVs. These viruses clustered with vv2-1 variant viruses from Oyo and Ogun states and less closely with vv2-2 isolates from Tanzania. The nucleotide identity of the sequences in this study ranged from 99.6 to 100 % with each other. These findings are further evidence of IBD outbreaks in vaccinated chicken flocks in Nigeria.
authors.affiliation: Applied Biotechnology Division, National Veterinary Research Institute, P.M.B, 930001, Vom, Plateau State, Nigeria. jidecoy@yahoo.com.
authors.forename: Olajide Adewale
authors.initials: OA
authors.lastname: Owolodun
authors.affiliation: Applied Biotechnology Division, National Veterinary Research Institute, P.M.B, 930001, Vom, Plateau State, Nigeria.
authors.forename: Bitrus
authors.initials: B
authors.lastname: Yakubu
authors.affiliation: Applied Biotechnology Division, National Veterinary Research Institute, P.M.B, 930001, Vom, Plateau State, Nigeria.
authors.forename: Anvou Rachael
authors.initials: AR
authors.lastname: Jambol
authors.affiliation: Applied Biotechnology Division, National Veterinary Research Institute, P.M.B, 930001, Vom, Plateau State, Nigeria.
authors.forename: Benshak John
authors.initials: BJ
authors.lastname: Audu
authors.affiliation: Viral Research Division, National Veterinary Research Institute, P.M.B, 930001, Vom, Plateau State, Nigeria.
authors.forename: Bajehson Banenat
authors.initials: BB
authors.lastname: Dogonyaro
authors.affiliation: Applied Biotechnology Division, National Veterinary Research Institute, P.M.B, 930001, Vom, Plateau State, Nigeria.
authors.forename: Pam Dachung
authors.initials: PD
authors.lastname: Luka
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000662:veterinary*; D002645:Chickens; D004196:Disease Outbreaks / Q000662:veterinary*; D007243:Infectious bursal disease virus / Q000235:genetics / Q000302:isolation & purification*; D009549:Nigeria / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000453:epidemiology*; D014611:Vaccination / Q000662:veterinary; D015678:Viral Structural Proteins / Q000235:genetics; D014774:Virulence / Q000235:genetics
chemical_list: D015678:Viral Structural Proteins
keywords: Commercial chickens; Infectious bursal disease; Plateau state; Sequencing; Vaccinated; Very virulent