White John R, Williams David T, Wang Jianning, Chen Honglei, Melville Lorna F, Davis Steven S, Weir Richard P, Certoma Andrea, Di Rubbo Antonio, Harvey Gemma, Lunt Ross A, Eagles Debbie
CSIRO Australian Animal Health Laboratory, Geelong, Victoria, Australia.
Department of Primary Industry and Resources, Berrimah Veterinary Laboratories, Northern Territory Government, Berrimah, Northern Territory, Australia.
Vet Med Sci. 2019 May;5(2):129-145. doi: 10.1002/vms3.156. Epub 2019 Feb 12.
Bluetongue virus (BTV), transmitted by midges (Culicoides sp), is distributed worldwide and causes disease in ruminants. In particular, BT can be a debilitating disease in sheep causing serious trade and socio-economic consequences at both local and global levels. Across Australia, a sentinel cattle herd surveillance program monitors the BTV activity. Prior to 2014, BTV-1, -2, -3, -7, -9, -15, -16, -20, -21 and -23 had been isolated in Australia, but no bluetongue disease has occurred in a commercial Australian flock. We routinely use a combination of serology, virus isolation, RT-PCR and next generation and conventional nucleotide sequencing technologies to detect and phylogenetically characterize incursions of novel BTV strains into Australia. Screening of Northern Territory virus isolates in 2015 revealed BTV-5, a serotype new to Australia. We derived the complete genome of this isolate and determined its phylogenetic relationship with exotic BTV-5 isolates. Gene segments 2, 6, 7 and 10 exhibited a close relationship with the South African prototype isolate RSArrrr/5. This was the first Australian isolation of a Western topotype of segment 10. Serological surveillance data highlighted the antigenic cross-reactivity between BTV-5 and BTV-9. Phylogenetic investigation of segments 2 and 6 of these serotypes confirmed their unconventional relationships within the BTV serogroup. Our results further highlighted a need for a revision of the current serologically based system for BTV strain differentiation and importantly, implied a potential for genome segments of pathogenic Western BTV strains to rapidly enter Southeast Asia. This emphasized a need for continued high-level surveillance of vectors and viruses at strategic locations in the north of Australia The expansion of routine characterization and classification of BTV to a whole genome approach is recommended, to better monitor the presence and level of establishment of novel Western topotype segments within the Australian episystem.
蓝舌病病毒（BTV）通过蠓（库蠓属）传播，在全球范围内分布，并在反刍动物中引发疾病。特别是，蓝舌病在绵羊中可能是一种使人衰弱的疾病，在地方和全球层面都会造成严重的贸易和社会经济后果。在澳大利亚各地，一个哨兵牛群监测项目对蓝舌病病毒的活动进行监测。2014年之前，澳大利亚已分离出BTV-1、-2、-3、-7、-9、-15、-16、-20、-21和-23，但澳大利亚的商业羊群中尚未发生蓝舌病。我们常规使用血清学、病毒分离、逆转录聚合酶链反应（RT-PCR）以及新一代和传统核苷酸测序技术的组合，来检测新型BTV毒株侵入澳大利亚的情况，并对其进行系统发育特征分析。2015年对北领地病毒分离株的筛查发现了BTV-5，这是一种在澳大利亚新出现的血清型。我们获得了该分离株的完整基因组，并确定了它与外来BTV-5分离株的系统发育关系。基因片段2、6、7和10与南非原型分离株RSArrrr/5表现出密切关系。这是澳大利亚首次分离到第10节段的西部拓扑型。血清学监测数据突出了BTV-5和BTV-9之间的抗原交叉反应性。对这些血清型的第2和6节段进行的系统发育研究证实了它们在蓝舌病病毒血清群中的非常规关系。我们的结果进一步凸显了对当前基于血清学的BTV毒株鉴别系统进行修订的必要性，重要的是，这意味着致病性西部BTV毒株的基因组片段有可能迅速进入东南亚。这强调了在澳大利亚北部的战略地点持续对媒介和病毒进行高水平监测的必要性。建议将蓝舌病病毒的常规特征分析和分类扩展到全基因组方法，以更好地监测澳大利亚流行系统中新型西部拓扑型片段的存在和建立水平。
