Molecular Virology and Host-Pathogen Interaction Unit, Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, USA.
Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan.
J Virol. 2015 Jan;89(1):594-604. doi: 10.1128/JVI.02704-14. Epub 2014 Oct 22.
Until the recent emergence of two human-pathogenic tick-borne phleboviruses (TBPVs) (severe fever with thrombocytopenia syndrome virus [SFTSV] and Heartland virus), TBPVs have been neglected as causative agents of human disease. In particular, no studies have addressed the global distribution of TBPVs, and consequently, our understanding of the mechanism(s) underlying their evolution and emergence remains poor. In order to provide a useful tool for the ecological and epidemiological study of TBPVs, we have established a simple system that can detect all known TBPVs, based on conventional reverse transcription-PCR (RT-PCR) with degenerate primer sets targeting conserved regions of the viral L genome segment. Using this system, we have determined that several viruses that had been isolated from ticks decades ago but had not been taxonomically identified are novel TBPVs. Full-genome sequencing of these viruses revealed a novel fourth TBPV cluster distinct from the three known TBPV clusters (i.e., the SFTS, Bhanja, and Uukuniemi groups) and from the mosquito/sandfly-borne phleboviruses. Furthermore, by using tick samples collected in Zambia, we confirmed that our system had enough sensitivity to detect a new TBPV in a single tick homogenate. This virus, tentatively designated Shibuyunji virus after the region of tick collection, grouped into a novel fourth TBPV cluster. These results indicate that our system can be used as a first-line screening approach for TBPVs and that this kind of work will undoubtedly lead to the discovery of additional novel tick viruses and will expand our knowledge of the evolution and epidemiology of TBPVs.
Tick-borne phleboviruses (TBPVs) have been largely neglected until the recent emergence of two virulent viruses, severe fever with thrombocytopenia syndrome virus and Heartland virus. Little is known about the global distribution of TBPVs or how these viruses evolved and emerged. A major hurdle to study the distribution of TBPVs is the lack of tools to detect these genetically divergent phleboviruses. In order to address this issue, we have developed a simple, rapid, and cheap RT-PCR system that can detect all known TBPVs and which led to the identification of several novel phleboviruses from previously uncharacterized tick-associated virus isolates. Our system can detect virus in a single tick sample and novel TBPVs that are genetically distinct from any of the known TBPVs. These results indicate that our system will be a useful tool for the surveillance of TBPVs and will facilitate understanding of the ecology of TBPVs.
直到最近两种人类致病性蜱传黄病毒（TBPV）（严重发热伴血小板减少综合征病毒 [SFTSV] 和 Heartland 病毒）的出现，TBPV 一直被忽视为人类疾病的病原体。特别是，没有研究探讨 TBPV 的全球分布，因此，我们对其进化和出现的机制的理解仍然很差。为了为 TBPV 的生态和流行病学研究提供有用的工具，我们基于针对病毒 L 基因组片段保守区域的简并引物组建立了一种简单的系统，可以检测所有已知的 TBPV。使用该系统，我们确定了数十年前从蜱中分离出来但尚未进行分类鉴定的几种病毒是新型 TBPV。这些病毒的全基因组测序揭示了一个与已知的三个 TBPV 簇（即 SFTS、Bhanja 和 Uukuniemi 组）和蚊/沙蝇传播的黄病毒不同的新型第四 TBPV 簇。此外，通过使用在赞比亚采集的蜱样本，我们证实我们的系统具有足够的灵敏度，可以在单个蜱匀浆中检测到一种新型 TBPV。该病毒暂命名为 Shibuyunji 病毒，以蜱采集地命名，归入一个新的第四 TBPV 簇。这些结果表明，我们的系统可以用作 TBPV 的一线筛选方法，这种工作无疑将导致发现更多新型蜱病毒，并扩大我们对 TBPV 进化和流行病学的认识。
直到最近两种毒力很强的病毒（严重发热伴血小板减少综合征病毒和 Heartland 病毒）的出现，蜱传黄病毒（TBPV）才被广泛忽视。关于 TBPV 的全球分布或这些病毒如何进化和出现的知之甚少。研究 TBPV 分布的主要障碍是缺乏检测这些遗传上有差异的黄病毒的工具。为了解决这个问题，我们开发了一种简单、快速且廉价的 RT-PCR 系统，可以检测所有已知的 TBPV，该系统还鉴定了从以前未表征的与蜱相关的病毒分离株中分离出的几种新型黄病毒。我们的系统可以在单个蜱样本中检测到病毒，并可以检测到与任何已知 TBPV 在遗传上都不同的新型 TBPV。这些结果表明，我们的系统将是监测 TBPV 的有用工具，并将有助于了解 TBPV 的生态学。
