Adamu J, Owoade A A, Abdu P A, Kazeem H M, Fatihu M Y
a Department of Veterinary Microbiology, Faculty of Veterinary Medicine , Ahmadu Bello University , Zaria , Nigeria.
Avian Pathol. 2013;42(5):420-33. doi: 10.1080/03079457.2013.822055. Epub 2013 Aug 6.
Outbreaks of infectious bursal disease in vaccinated chicken flocks are frequent in Nigeria. For the control of infectious bursal disease, live vaccines based on foreign infectious bursal disease virus (IBDV) strains are used. The present study investigated the phylogenetic relationship between field and vaccine IBDV strains from northwestern Nigeria. Thirty field IBDV strains and three commercial vaccines strains were characterized through sequencing the VP2 hypervariable region. In addition, the complete genome segment A coding region for two vaccines and two field strains was sequenced. The deduced amino acid sequences (position 212 to 331) of IBDV strains from Nigeria and other regions of the world were aligned and possible regional and virulence markers were identified associated with VP2 minor hydrophilic peaks. Reversion to virulence of a vaccine strain with a Q to L mutation at position 253 was observed. Phylogenetic analyses revealed a unique cluster of northwest Nigerian field IBDV strains alone or related to imported characterized classical and very virulent IBDV vaccines. The results suggest that when IBDV strains spread from their region of origin to a different region they mutate alongside indigenous field strains but may retain their identity on the VP2 region.
在尼日利亚，接种过疫苗的鸡群中传染性法氏囊病疫情频发。为控制传染性法氏囊病，使用了基于国外传染性法氏囊病病毒（IBDV）毒株的活疫苗。本研究调查了尼日利亚西北部地区的IBDV野毒株与疫苗株之间的系统发育关系。通过对VP2高变区进行测序，对30株IBDV野毒株和3株商业疫苗株进行了特征分析。此外，还对两种疫苗和两株野毒株的完整基因组A片段编码区进行了测序。对来自尼日利亚和世界其他地区的IBDV毒株推导的氨基酸序列（第212至331位）进行比对，并确定了与VP2小亲水区相关的可能的区域和毒力标记。观察到在第253位发生Q到L突变的疫苗株出现了毒力返强现象。系统发育分析显示，尼日利亚西北部地区的IBDV野毒株单独形成一个独特的簇，或与进口的已鉴定的经典和超强毒IBDV疫苗相关。结果表明，当IBDV毒株从其起源地区传播到不同地区时，它们会与本地野毒株一起发生突变，但在VP2区域可能会保留其特征。
