Mohamed Mahmoud H A, El-Sabagh Ibrahim M, Al-Habeeb Malik A, Al-Hammady Yousef M
Department of Clinical Studies, College of Veterinary Medicine, King Faisal University, Al-Hufof, 31982, Saudi Arabia; Department of Avian and Rabbit Medicine, Faculty of Veterinary Medicine, Zagazig University, 44519, Zagazig, Egypt.
Central Biotechnology Laboratory, College of Veterinary Medicine, King Faisal University, Al-Hufof, 31982, Saudi Arabia; Department of Virology, Faculty of Veterinary Medicine, Cairo University, 12211, Giza, Egypt.
Vet World. 2016 Jun;9(6):572-8. doi: 10.14202/vetworld.2016.572-578. Epub 2016 Jun 10.
The aim of this study was to demonstrate the genomic features of Meq gene of Marek's disease virus (MDV) recently circulating in Saudi Arabia (SA).
Two poultry flocks suffering from mortalities and visceral tumors were presented to the Veterinary Teaching Hospital, King Faisal University, SA. Subjected to different diagnostic procedures: Case history, clinical signs, and necropsy as well as polymerase chain reaction followed by Meq gene sequence analysis.
Case history, clinical signs, and necropsy were suggestive of MDV infection. The Meq gene was successfully detected in liver and spleen of infected chickens. A 1062 bp band including the native Meq ORF in addition to a 939 bp of S-Meq (short isoform of Meq) were amplified from Saudi 01-13 and Saudi 02-13, respectively. The nucleotide and deduced amino acids sequences of the amplified Meq genes of both Saudi isolates showed distinct polymorphism when compared with the standard USA virulent isolates Md5 and GA. The sequence analysis of the S-Meq gene showed a 123 bp deletion representing 41 amino acids between two proline-rich areas without any frameshift. The Meq gene encoded four repeats of proline-rich repeats (PRRs sequences), whereas the S-Meq contains only two PRRs. Interestingly, the phylogenetic analysis revealed that both of SA MDV isolates are closely related to the MDV strains from Poland.
The two MDV isolates contain several nucleotide polymorphisms resulting in distinct amino acid substitutions. It is suggested that migratory and wild birds, as well as world trading of poultry and its by-products, have a great contribution in the transmission of MDVs overseas.
本研究旨在揭示近期在沙特阿拉伯（SA）流行的马立克氏病病毒（MDV）Meq基因的基因组特征。
将两个出现死亡和内脏肿瘤的家禽群送至沙特阿拉伯费萨尔国王大学兽医学院教学医院。进行了不同的诊断程序：病史、临床症状、尸检以及聚合酶链反应，随后进行Meq基因序列分析。
病史、临床症状和尸检结果提示为MDV感染。在感染鸡的肝脏和脾脏中成功检测到Meq基因。分别从沙特01 - 13和沙特02 - 13中扩增出一条1062 bp的条带，其中包括天然Meq开放阅读框（ORF），以及一条939 bp的S - Meq（Meq的短异构体）条带。与标准美国强毒株Md5和GA相比，两个沙特分离株扩增的Meq基因的核苷酸和推导氨基酸序列显示出明显的多态性。S - Meq基因的序列分析显示，在两个富含脯氨酸的区域之间有一个123 bp的缺失，代表41个氨基酸，且无移码现象。Meq基因编码四个富含脯氨酸重复序列（PRRs序列），而S - Meq仅包含两个PRRs。有趣的是，系统发育分析表明，两个沙特MDV分离株均与来自波兰的MDV毒株密切相关。
这两个MDV分离株包含多个核苷酸多态性，导致明显的氨基酸替换。提示候鸟、野生鸟类以及家禽及其副产品的国际贸易在MDV的海外传播中起很大作用。
