Abstract：
Fifty-seven Gallid alphaherpesvirus 2 (GaHV-2) isolates, collected during a 30-year period (1990-2019) from commercial poultry flocks affected by Marek\'s disease (MD), were molecularly characterised. The GaHV-2 meq gene was amplified and sequenced to evaluate the virus virulence, based on the number of PPPPs within the proline-rich repeats (PRRs) of its transactivation domain. The present illustration of virus virulence evaluation on a large scale of field virus isolates by molecular analysis exemplifies the practical benefit and usefulness of the molecular marker in commercial GaVH-2 isolates. The alternative assay of GaVH-2 virulence pathotyping is the classical Gold Standard ADOL method, which is difficult and impossible to employ on a large scale using the Specific Pathogen Free (SPF) chicks of the ADOL strains kept in isolators for two months. The phylogenetic analysis performed in the present study showed that the meq gene amino acid sequences of the 57 Israeli strains divide into 16 phylogenetic branches. The virulence evaluation was performed in comparison with 36 GaHV-2 prototype strains, previously characterised by the in vivo Gold Standard ADOL assay. The results obtained revealed that the GaHV-2 strains circulating in Israel have evolved into a higher virulence potential during the years, as the four-proline stretches number in the meq gene decreased over the investigated period, typically of very virulent virus prototypes. The present study supports the meq gene molecular markers for the assessment of field GaVH-2 strains virulence.
摘要：
57个Gallidα疱疹病毒2型（GaHV-2）分离株，在30年期间（1990-2019年）从受马立克氏病（MD）影响的商业家禽群中收集，被分子表征。对GaHV-2meq基因进行扩增和测序以评估病毒的毒力，基于其反式激活域的富含脯氨酸的重复序列(PRR)内的PPPPs的数量。通过分子分析对大规模田间病毒分离株进行病毒毒力评估的当前说明举例说明了分子标记在商业GaVH-2分离株中的实际益处和有用性。GaVH-2毒力分型的替代方法是经典的黄金标准ADOL方法，使用在隔离物中保存两个月的ADOL菌株的无特定病原体（SPF）雏鸡难以且不可能大规模使用。本研究中进行的系统发育分析表明，57个以色列菌株的meq基因氨基酸序列分为16个系统发育分支。与36株GaHV-2原型菌株相比，进行了毒力评估。先前通过体内黄金标准ADOL测定法表征。获得的结果表明，多年来，在以色列传播的GaHV-2菌株已经演变成更高的毒力潜力，随着meq基因中的四脯氨酸延伸数在研究期间减少，通常是非常致命的病毒原型。本研究支持meq基因分子标记用于评估田间GaVH-2菌株的毒力。
