Hamada Rania, Metwally Samy, Polat Meripet, Borjigin Liushiqi, Ali Alsagher O, Abdel-Hady A A A, Mohamed Adel E A, Wada Satoshi, Aida Yoko
Photonics Control Technology Team, RIKEN Center for Advanced Photonics, Saitama, Japan.
Department of Animal Medicine, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt.
Front Vet Sci. 2020 Sep 10;7:608. doi: 10.3389/fvets.2020.00608. eCollection 2020.
Bovine leukemia virus (BLV) causes enzootic bovine leukosis (EBL), the most common neoplastic disease in cattle worldwide. The first EBL outbreak in Egypt was reported in 1997. To date, there are few studies regarding BLV diagnosis using only serological detection and no studies investigating the distribution of BLV provirus, which is the retroviral genome integrated into the host genome, in Egypt. The genetic characteristics of Egyptian BLV strains are also unknown. Therefore, we aimed to detect BLV provirus and determine BLV genetic variability among dairy cattle in Egypt. We collected 270 blood samples of dairy cattle from 24 farms located in five provinces in Egypt. Out of the 270 samples, 58 (21.5%) were positive for BLV provirus. Phylogenetic analysis based on 18 420-bp selected sequences out of 50 isolates of the BLV -gp51 gene demonstrated that Egyptian BLV isolates were clustered into genotype-1 and-4, among 11 genotypes detected worldwide. Furthermore, phylogenetic analysis and alignment of the 501-bp sequence of the gp51 gene revealed that at least six genetically different strains are present in Egypt. Genotype-1 isolates comprised four different strains (G1-a, G1-b, G1-c, and G1-d) and genotype-4 isolates included two different strains (G4-x and G4-y). Moreover, in one farm with 100% infection rate, we identified three isolates of G1-a strain, 35 isolates of G4-x strain, and two isolates of G4-y strain. Overall, this study provides the new report on molecular prevalence of BLV in Egypt and records the coexistence of BLV genotype-1 and-4 in Egyptian cattle.
牛白血病病毒（BLV）可引发地方流行性牛白血病（EBL），这是全球牛群中最常见的肿瘤性疾病。埃及于1997年首次报告了EBL疫情。迄今为止，仅有少数关于仅使用血清学检测进行BLV诊断的研究，而在埃及尚无关于调查整合到宿主基因组中的逆转录病毒基因组——BLV前病毒分布情况的研究。埃及BLV毒株的遗传特征也尚不明确。因此，我们旨在检测埃及奶牛中的BLV前病毒并确定其遗传变异性。我们从埃及五个省份的24个农场采集了270份奶牛血样。在这270份样本中，58份（21.5%）BLV前病毒呈阳性。基于从50株BLV -gp51基因分离株中选取的18条420 bp序列进行的系统发育分析表明，在全球检测到的11种基因型中，埃及BLV分离株被聚类为基因型1和4。此外，对gp51基因501 bp序列的系统发育分析和比对显示，埃及至少存在六种遗传上不同的毒株。基因型1分离株包含四种不同的毒株（G1-a、G1-b、G1-c和G1-d），基因型4分离株包括两种不同的毒株（G4-x和G4-y）。此外，在一个感染率达100%的农场中，我们鉴定出3株G1-a毒株、35株G4-x毒株和2株G4-y毒株。总体而言，本研究提供了埃及BLV分子流行情况的新报告，并记录了BLV基因型1和4在埃及牛群中共存的情况。
