Hernández Martín, Tomás Gonzalo, Marandino Ana, Iraola Gregorio, Maya Leticia, Mattion Nora, Hernández Diego, Villegas Pedro, Banda Alejandro, Panzera Yanina, Pérez Ruben
a Sección Genética Evolutiva, Departamento de Biología Animal , Instituto de Biología, Facultad de Ciencias, Universidad de la República , Montevideo , Uruguay.
Avian Pathol. 2015;44(3):212-21. doi: 10.1080/03079457.2015.1025696. Epub 2015 Apr 2.
Infectious bursal disease virus (IBDV) is one of the most concerning health problems for world poultry production. IBDVs comprise four well-defined evolutionary lineages known as classic (c), classic attenuated (ca), variant (va) and very virulent (vv) strains. Here, we characterized IBDVs from South America by the genetic analysis of both segments of the viral genome. Viruses belonging to c, ca and vv strains were unambiguously classified by the presence of molecular markers and phylogenetic analysis of the hypervariable region of the vp2 gene. Notably, the majority of the characterized viruses (9 out of 15) could not be accurately assigned to any of the previously described strains and were then denoted as distinct (d) IBDVs. These dIBDVs constitute an independent evolutionary lineage that also comprises field IBDVs from America, Europe and Asia. The hypervariable VP2 sequence of dIBDVs has a unique and conserved molecular signature (272T, 289P, 290I and 296F) that is a diagnostic character for classification. A discriminant analysis of principal components (DAPC) also identified the dIBDVs as a cluster of genetically related viruses separated from the typical strains. DAPC and genetic distance estimation indicated that the dIBDVs are one of the most genetically divergent IBDV lineages. The vp1 gene of the dIBDVs has non-vvIBDV markers and unique nucleotide and amino acid features that support their divergence in both genomic segments. The present study suggests that the dIBDVs comprise a neglected, highly divergent lineage that has been circulating in world poultry production since the early time of IBDV emergence.
传染性法氏囊病病毒（IBDV）是全球家禽生产中最令人担忧的健康问题之一。IBDV包括四个明确的进化谱系，即经典（c）、经典弱毒（ca）、变异（va）和超强毒（vv）毒株。在此，我们通过对病毒基因组两个片段的遗传分析对来自南美洲的IBDV进行了特征描述。通过分子标记的存在以及vp2基因高变区的系统发育分析，明确区分了属于c、ca和vv毒株的病毒。值得注意的是，大多数已鉴定的病毒（15株中的9株）无法准确归类到任何先前描述的毒株中，因此被标记为独特（d）IBDV。这些dIBDV构成了一个独立的进化谱系，其中还包括来自美洲、欧洲和亚洲的田间IBDV。dIBDV的高变VP2序列具有独特且保守的分子特征（272T、289P、290I和296F），这是用于分类的诊断特征。主成分判别分析（DAPC）也将dIBDV鉴定为与典型毒株分离的一组遗传相关病毒。DAPC和遗传距离估计表明，dIBDV是遗传差异最大的IBDV谱系之一。dIBDV的vp1基因具有非vvIBDV标记以及独特的核苷酸和氨基酸特征，这支持了它们在两个基因组片段中的差异。本研究表明，dIBDV构成了一个被忽视的、高度分化的谱系，自IBDV出现早期以来一直在全球家禽生产中传播。
