title: Molecular characterization of infectious bursal disease viruses detected in vaccinated commercial broiler flocks in Lusaka, Zambia.
abstract: Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive viral disease of young chickens and remains one of the economically most important diseases threatening the poultry industry worldwide. In this study, 16 and 11 nucleotide sequences of the VP2 hypervariable region (VP2-HVR) and part of VP1, respectively, of IBD virus (IBDV) detected in vaccinated broiler chickens in Lusaka in 2012 were determined. Phylogenetic analysis revealed that these Zambian IBDVs separated into three genotypes of very virulent (VV) IBDVs. Although the majority of these viruses belonged to the African VV type (VV1), which consisted of viruses from West Africa, South Africa and Zambia, one virus belonged to the East African VV type (VV2). Interestingly, a Zambian IBDV belonging to the VV3 genotype (composed of viruses from several continents) clustered with attenuated vaccine strains. Although sequence analysis of VP2-HVR showed that all detected Zambian IBDVs had conserved putative virulence marker amino acids (i.e., 222A, 242I, 256I, 294I and 299S), one virus had two unique amino acid substitutions, N280S and E300A. This study demonstrates the diversity of Zambian IBDVs and documents for the first time the possible involvement of attenuated vaccine strains in the epidemiology of IBD in Zambia. Strict biosecurity of poultry farms, monitoring of live vaccine use in the field, surveillance and characterization of IBDV in poultry and development of a vaccine from local or regional IBDV field strains are recommended for improved IBD control in Zambia.
authors.affiliation: Department of Disease Control, School of Veterinary Medicine, The University of Zambia, PO Box 32379, Lusaka, Zambia.|Department of Veterinary Services and Livestock Development, Ministry of Agriculture and Livestock, PO Box 21, Siavonga, Zambia.
authors.forename: Kunda
authors.initials: K
authors.lastname: Ndashe
authors.affiliation: Department of Disease Control, School of Veterinary Medicine, The University of Zambia, PO Box 32379, Lusaka, Zambia. esikabala@yahoo.com.
authors.forename: Edgar
authors.identifier: http://orcid.org/0000-0001-9423-0816
authors.initials: E
authors.lastname: Simulundu
authors.affiliation: Department of Para Clinical Studies, School of Veterinary Medicine, The University of Zambia, PO Box 32379, Lusaka, Zambia.
authors.forename: Bernard M
authors.initials: BM
authors.lastname: Hang'ombe
authors.affiliation: Department of Para Clinical Studies, School of Veterinary Medicine, The University of Zambia, PO Box 32379, Lusaka, Zambia.
authors.forename: Ladslav
authors.initials: L
authors.lastname: Moonga
authors.affiliation: Department of Virology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Okayama, 700-8558, Japan.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Ogawa
authors.affiliation: Department of Disease Control, School of Veterinary Medicine, The University of Zambia, PO Box 32379, Lusaka, Zambia.|Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Kita-20, Nishi-10, Kita-ku, Sapporo, 001-0020, Japan.
authors.forename: Ayato
authors.initials: A
authors.lastname: Takada
authors.affiliation: Department of Disease Control, School of Veterinary Medicine, The University of Zambia, PO Box 32379, Lusaka, Zambia.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Mweene
mesh_terms: D000818:Animals; D018175:Birnaviridae Infections / Q000662:veterinary* / Q000821:virology; D002645:Chickens; D016000:Cluster Analysis; D005838:Genotype; D007243:Infectious bursal disease virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000821:virology*; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D015678:Viral Structural Proteins / Q000235:genetics; D015024:Zambia
chemical_list: D012367:RNA, Viral; D015678:Viral Structural Proteins