School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, USA.
College of Marine Science, University of South Florida, Saint Petersburg, FL, USA.
ISME J. 2020 Jul;14(7):1755-1767. doi: 10.1038/s41396-020-0642-2. Epub 2020 Apr 14.
Parasitic flatworms (Neodermata) infect all vertebrates and represent a significant health and economic burden worldwide due to the debilitating diseases they cause. This study sheds light for the first time into the virome of a tapeworm by describing six novel RNA virus candidate species associated with Schistocephalus solidus, including three negative-strand RNA viruses (order Jingchuvirales, Mononegavirales, and Bunyavirales) and three double-stranded RNA viruses. Using in vitro culture of S. solidus, controlled experimental infections and field sampling, we demonstrate that five of these viruses are vertically transmitted, and persist throughout the S. solidus complex life cycle. Moreover, we show that one of the viruses, named Schistocephalus solidus rhabdovirus (SsRV1), is excreted by the parasite and transmitted to parasitized hosts indicating that it may impact S. solidus-host interactions. In addition, SsRV1 has a basal phylogenetic position relative to vertebrate rhabdoviruses suggesting that parasitic flatworms could have contributed to virus emergence. Viruses similar to four of the S. solidus viruses identified here were found in geographically distant S. solidus populations through data mining. Further studies are necessary to determine if flatworm viruses can replicate in parasitized hosts, how they contribute to parasite infection dynamics and if these viruses could be targeted for treatment of parasitic disease.
寄生虫扁形动物（新皮头亚纲）感染所有脊椎动物，并因引起的使人虚弱的疾病而在全球范围内造成重大的健康和经济负担。本研究首次描述了与 S. solidus 相关的六种新型 RNA 病毒候选种，揭示了绦虫的病毒组，其中包括三种负链 RNA 病毒（Jingchuvirales、单负股病毒目和 Bunyavirales）和三种双链 RNA 病毒。通过 S. solidus 的体外培养、受控的实验感染和现场采样，我们证明其中五种病毒是垂直传播的，并在 S. solidus 复杂的生命周期中持续存在。此外，我们表明，其中一种病毒，命名为 S. solidus rhabdovirus (SsRV1)，由寄生虫排出并传播给受感染的宿主，表明它可能影响 S. solidus-宿主相互作用。此外，SsRV1 相对于脊椎动物弹状病毒具有基础的系统发育地位，这表明寄生虫扁形动物可能促成了病毒的出现。通过数据挖掘，在地理上遥远的 S. solidus 种群中发现了与这里鉴定的四种 S. solidus 病毒相似的病毒。需要进一步的研究来确定扁形动物病毒是否可以在寄生宿主中复制，它们如何影响寄生虫感染动态，以及这些病毒是否可以作为寄生虫病治疗的靶点。
