title: Phylogenetic analysis of the polyprotein coding region of an infectious South African bursal disease virus (IBDV) strain.
abstract: Infectious bursal disease virus (IBDV) causes Gumboro disease, which is highly contagious and immunosuppressive in young chickens. A virulent form of IBDV reached South Africa in 1989 and to date there has been little molecular information available for this strain. In this study, the polyprotein coding region of the South African strain SA-KZN95 was sequenced and analysed along with 52 representative sequences of other serotype I and II strains. We explored the relative impact of recombination on phylogenetic reconstruction using a multidimensional scaling approach. Phylogenetic analyses consistently placed the South African isolate within the very virulent IBDV clade. Selection analyses were also conducted to identify evolutionarily relevant amino acid residues. Previously, 19 residues in the polyprotein were shown to be potentially diagnostic for the different IBDV pathotypes. This study identified an additional two unique residues in the polyprotein which may be used as genetic signatures in future viral identifications. Better strain identification would aid in the development and application of vaccines.
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa.
authors.forename: Phillia R
authors.initials: PR
authors.lastname: Vukea
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa.
authors.forename: Sandi
authors.initials: S
authors.lastname: Willows-Munro
authors.affiliation: Vetdiagnostix, Veterinary Pathology Services, Pietermaritzburg, KwaZulu-Natal, South Africa.
authors.forename: Roger F
authors.initials: RF
authors.lastname: Horner
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa. Electronic address: Coetzer@ukzn.ac.za.
authors.forename: Theresa H T
authors.initials: TH
authors.lastname: Coetzer
mesh_terms: D000596:Amino Acids; D000818:Animals; D018175:Birnaviridae Infections / Q000662:veterinary / Q000821:virology*; D002645:Chickens; D019143:Evolution, Molecular; D014644:Genetic Variation; D007243:Infectious bursal disease virus / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D020815:Polyproteins / Q000235:genetics*; D011201:Poultry Diseases / Q000821:virology*; D011995:Recombination, Genetic; D012703:Serotyping; D013019:South Africa; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D000596:Amino Acids; D020815:Polyproteins; D014764:Viral Proteins
keywords: Infectious bursal disease virus (IBDV); Phylogenetic analysis; Polyprotein; Recombination analysis; South African isolate; vvIBDV