Department of Microbiology, Faculty of Veterinary Medicine, Firat University, 23110, Elazig, Turkey.
Department of Pathology, Faculty of Veterinary Medicine, Firat University, Elazig, Turkey.
BMC Vet Res. 2022 Jan 12;18(1):30. doi: 10.1186/s12917-021-03130-2.
Marek's disease (MD) is a lymphoproliferative disease caused by Gallid alphaherpesvirus 2 (GaHV-2, MDV-1), which primarily affects chickens. However, the virus is also able to induce tumors and polyneuritis in turkeys, albeit less frequently than in chickens.
This is the first study in Turkey reporting the molecular characterization of a MDV-1 strain detected in a flock of backyard turkeys exhibiting visceral lymphoma. Here, MEQ, vIL-8, pp38 and 132-bp tandem repeat regions, which are frequently preferred in the pathotyping of MDV-1, were examined. It was determined that the MEQ gene of MDV-1/TR-21/turkey strain obtained in the present study encoded 339 amino acids (1020 nt) and had four proline-rich repeat regions (PPPP). Based on the nucleotide sequence of the MEQ gene of the MDV-1/TR-21/turkey strain, a phylogenetic tree was created using the MEGA-X software with the Maximum Likelihood Method (in 1000 replicates). Our strain was highly identical (> 99.8) to the Italian/Ck/625/16, Polish (Polen5) and some Turkish (Layer-GaHV-2-02-TR-2017, Tr/MDV-1/19) MDV-1 strains. Also, nt and aa sequences of the MEQ gene of our strain were 99.1 and 99.41% identical to another Turkish strain (MDV/Tur/2019) originated from chickens. Sequence analysis of pp38 and vIL-8 genes also supported the above finding. The identity ratios of nucleotide and amino acid sequences of vIL-8 and pp38 genes of MDV-1/TR-21/turkey strain were 99.64-100% and 99.79-100%, respectively, when compared with those of the Polish strain. According to 132-bp tandem repeat PCR results, the MDV-1/TR-21/turkey strain had five copies.
These results suggested that the MDV-1/TR-21/turkey strain obtained from backyard turkeys can be either very virulent or very virulent plus pathotype, though experimental inoculation is required for precise pathotyping.
马立克氏病（MD）是一种由 Gallid alphaherpesvirus 2（GaHV-2，MDV-1）引起的淋巴组织增生性疾病，主要影响鸡。然而，该病毒也能够在火鸡中诱导肿瘤和多发性神经炎，尽管其发病率低于鸡。
这是土耳其首例报告在一群后院火鸡中发现 MDV-1 株的分子特征的研究，这些火鸡表现出内脏淋巴瘤。在这里，对 MEQ、vIL-8、pp38 和 132-bp 串联重复区进行了检测，这些区域通常是 MDV-1 病理分型的首选。研究表明，本研究中获得的 MDV-1/TR-21/火鸡株的 MEQ 基因编码 339 个氨基酸（1020nt），并具有四个富含脯氨酸的重复区（PPPP）。基于 MDV-1/TR-21/火鸡株 MEQ 基因的核苷酸序列，使用 MEGA-X 软件中的最大似然法（在 1000 次重复中）构建了一个系统发育树。我们的菌株与意大利/Ck/625/16、波兰（波兰 5 号）和一些土耳其（Layer-GaHV-2-02-TR-2017、Tr/MDV-1/19）MDV-1 株高度一致（>99.8%）。此外，我们菌株 MEQ 基因的 nt 和 aa 序列与另一个源自鸡的土耳其株（MDV/Tur/2019）分别有 99.1%和 99.41%的一致性。pp38 和 vIL-8 基因的序列分析也支持了上述发现。与波兰株相比，MDV-1/TR-21/火鸡株 vIL-8 和 pp38 基因的核苷酸和氨基酸序列的同一性比率分别为 99.64-100%和 99.79-100%。根据 132-bp 串联重复 PCR 结果，MDV-1/TR-21/火鸡株有五个拷贝。
从后院火鸡中获得的 MDV-1/TR-21/火鸡株可能是非常致瘤或非常致瘤加病理型，尽管需要进行实验接种才能进行准确的病理分型。
