Infectious bursal disease virus (IBDV) is the aetiological agent of a highly contagious chicken immunodeficiency disorder known as Gumboro disease, which cause severe economic loses to the poultry worldwide. The emergence of very virulent IBDV strains (vvIBDV) during the late 80s resulted in drastic changes to the epidemiology of IBDV with a dramatic increase in the mortality of the animals affected. Molecular studies determined that the emergence of the vvIBDV was a consequence of a genomic reorganization of IBDV known as reassortant event by which the virus combined two emergent genetic background vvIBDV for segment A and vvIBDV for segment B. In the current study, a retrospective analysis was conducted, and samples collected during acute outbreaks of Gumboro disease in Poland during 1992–2015 were submitted to sequencing and further molecular and phylogenetic analyses. The results obtained not only revealed a high genetic diversity for Polish IBDV strains but a new population of IBDV was identified. These novel reassortant strains with a unique genetic background contain the segment A from very virulent strains and segment B from an unidentified source, phylogenetically segregated and classified as ‘transitional lineage’. The results obtained also showed the presence of this new lineage in Finland, evidencing the expansion of this new genomic reorganized viral strain in Europe representing an additional threat to the global situation of IBDV.

中文翻译：

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在欧洲，引起传染性法氏囊病病毒的新型致病性重配株的出现和扩展。

传染性法氏囊病病毒（IBDV）是一种高度传染的鸡免疫缺陷性疾病（称为Gumboro病）的病原学物质，该疾病在全球范围内给家禽造成了严重的经济损失。在80年代后期出现了极强力的IBDV毒株（vvIBDV），导致IBDV流行病学发生了巨大变化，受影响动物的死亡率急剧增加。分子研究确定vvIBDV的出现是IBDV基因组重组的结果，这种重组被称为重配事件，通过该事件病毒将两个新兴的遗传背景vvIBDV用于A区和vvIBDV用于B区。在本研究中，进行了回顾性分析。进行 在1992年至2015年间，波兰发生了Gumboro病的急性暴发期间收集的样本，并进行了测序以及进一步的分子和系统发育分析。获得的结果不仅表明波兰IBDV菌株具有很高的遗传多样性，而且还发现了新的IBDV种群。这些具有独特遗传背景的新颖重配株包含来自极强毒株的A区和来自未知来源的B区，在系统发育上被分离并归类为“过渡谱系”。获得的结果还表明该新谱系在芬兰的存在，证明了这种新的基因组重组病毒株在欧洲的扩张，这对IBDV的全球形势构成了另外的威胁。获得的结果不仅表明波兰IBDV菌株具有很高的遗传多样性，而且还发现了新的IBDV种群。这些具有独特遗传背景的新颖重配株包含来自极强毒株的A区和来自未知来源的B区，在系统发育上被分离并归类为“过渡谱系”。获得的结果还表明该新谱系在芬兰的存在，证明了这种新的基因组重组病毒株在欧洲的扩张，这对IBDV的全球形势构成了另外的威胁。获得的结果不仅表明波兰IBDV菌株具有很高的遗传多样性，而且还发现了新的IBDV种群。这些具有独特遗传背景的新颖重配株包含来自极强毒株的A区和来自未知来源的B区，在系统发育上被分离并归类为“过渡谱系”。获得的结果还表明该新谱系在芬兰的存在，证明了这种新的基因组重组病毒株在欧洲的扩张，这对IBDV的全球形势构成了另外的威胁。系统发育上分离并归类为“过渡谱系”。获得的结果还表明该新谱系在芬兰的存在，证明了这种新的基因组重组病毒株在欧洲的扩张，这对IBDV的全球形势构成了另外的威胁。系统发育上分离并归类为“过渡谱系”。获得的结果还表明该新谱系在芬兰的存在，证明了这种新的基因组重组病毒株在欧洲的扩张，这对IBDV的全球形势构成了另外的威胁。