Behind the hellish Ebola epidemic ravaging West Africa lies an agent that fittingly embodies the mad contradictions of a nightmare. It is alive yet dead, simple yet complex, mindless yet prophetic, seemingly able to anticipate our every move.在埃博拉疫情肆虐西非的背后有一个刚好能反映一场噩梦对立之处的载体。它死掉但早已杀了，非常简单而又简单，盲目而又不具先知性，或许需要意识到我们的每一个行径。For scientists who study the evolution and behavior of viruses, the Ebola pathogen is performing true to its vast, ancient and staggeringly diverse kind. By all evidence, researchers say, viruses have been parasitizing living cells since the first cells arose on earth nearly four billion years ago.对于研究病毒演进及不道德的科学家来说，埃博拉病原体的本质与数量可观、历史悠久、形态各异的各种病毒并无有所不同。

研究人员称之为，所有的证据都表明，自约40亿年前地球上经常出现第一批细胞开始，病毒就仍然宿主在活细胞当中。Some researchers go so far as to suggest that viruses predate their hosts. That they essentially invented cells as a reliable and renewable resource they could then exploit for the sake of making new viral particles.一些研究人员甚至回应，病毒迟至宿主经常出现。它们基本上建构了细胞，并将其当作可信的、可沿袭的资源，日后可以用来产生新病毒。

It was the primordial viral collective, said Luis P. Villarreal, director of the Center for Virus Research at the University of California, Irvine, that originated the capacity for life to be self-sustaining.加州大学欧文分校(University of California, Irvine)病毒研究中心(Center for Virus Research)主任路易斯·维拉里尔(Luis P. Villarreal)说道，“生命的自我保持能力源自”完整的病毒“团体”。Viruses are not just these threatening or annoying parasitic agents, he added. Theyre the creative front of biology, where things get figured out, and they always have been.“病毒某种程度是危险性的、令人讨厌的宿主体，”他还说道。“它们还正处于生物学的创意前沿，为问题的解决问题做到着贡献，它们也仍然都是这样的。”Researchers are deeply impressed by the depth and breadth of the viral universe, or virome. Viruses have managed to infiltrate the cells of every life form known to science. They infect animals, plants, bacteria, slime mold, even larger viruses. They replicate in their host cells so prodigiously and stream out into their surroundings so continuously that if you collected all the viral flotsam afloat in the worlds oceans, the combined tonnage would outweigh that of all the blue whales.病毒世界的深度与广度给研究人员留给了深刻印象的印象。

病毒已顺利入侵科学界未知的每一种生命形式的细胞中。它们不会病毒感染动物、植物、细菌、粘液菌，甚至是较小的病毒。它们在宿主细胞中大量拷贝，大大涌进周围环境。

如果将全球海洋里飘浮的所有病毒性物质搜集一起，总重会多达所有蓝鲸的重量。Not that viruses want to float freely. As so-called obligate parasites entirely dependent on host cells to replicate their tiny genomes and fabricate their protein packages newborn viruses, or virions, must find their way to fresh hosts or they will quickly fall apart, especially when exposed to sun, air or salt.病毒并非想四处流落。由于所谓的专性寄生物几乎倚赖宿主细胞拷贝它们大于的基因组及制备蛋白，因此新的产生的病毒或病毒粒子必需寻找新的宿主，否则它们就不会很快瓦解，尤其是曝露在太阳、空气或盐中的时候。

Drying out is a death knell for viral particles, said Lynn W. Enquist, a virologist at Princeton.普林斯顿大学(Princeton University)病毒学家林恩·W·恩奎斯特(Lynn W. Enquist)说道，“对于病毒粒子来说，潮湿的环境意味著丧生。”How long shed virions can persist if kept moist and unbuffeted — for example, in soil or in body excretions like blood or vomit — is not always clear but may be up to a week or two. That is why the sheets and clothing of Ebola patients must be treated as hazardous waste and surfaces hosed down with bleach.目前并不是十分确切，如果维持干燥且受压制，例如在土壤或血液、呕吐物等人体排泄的物质中，分离出来的病毒粒子需要保持多长时间，但有可能最少是一两周。

因此，埃博拉患者的床单和衣服必需被当成危险废物处置，表面都要用漂白剂冲洗。Viruses are masters at making their way from host to host and cell to cell, using every possible channel. Whenever biologists discover a new way that body cells communicate with one another, sure enough, theres a virus already tapping into exactly that circuit in its search for new meat.病毒擅于通过一切有可能的途径，从一个宿主转入另一个宿主，从一个细胞转入另一个细胞。每当生物学家找到身体细胞互相交换信息的新方式后，果然就早已有病毒在利用这个地下通道，找寻新的目标。

Reporting recently in Proceedings of the National Academy of Sciences, Karla Kirkegaard, a professor of microbiology and genetics at Stanford University School of Medicine, and her colleagues described a kind of unconventional secretion pathway based on so-called autophagy, or self-eating, in which cells digest small parts of themselves and release the pieces into their surroundings as signaling molecules targeted at other cells — telling them, for example, that its time for a new round of tissue growth.最近，斯坦福大学医学院(Stanford University School of Medicine)微生物学及基因学教授卡拉·柯克加德(Karla Kirkegaard)和同事在《国家科学院院刊》(Proceedings of the National Academy of Sciences)发表文章叙述了一种基于所谓的自噬的“非传统黏液”途径，即细胞消化一部分自身细胞质，然后将它们获释到周围的环境中，当作针对其他细胞的信号分子，比如，告诉他它们，现在是展开新一轮的组织生长的时候了。The researchers determined that the poliovirus can exploit the autophagy conduit to cunning effect. Whereas it was long believed that new polio particles could exit their natal cell only by bursting it open and then seeking new cells to infect, the researchers found that the virions could piggyback to freedom along the autophagy pathway.研究人员推断，小儿麻痹症病毒需要十分精妙地利用这条自噬途径来达成协议目的。从前，人们仍然以为，新的小儿麻痹症病毒粒子瓦解产生这些病毒的细胞的唯一方式就是冲破细胞，找寻并病毒感染新的细胞，而研究人员找到病毒粒子需要在自噬的过程中搭便车，从而取得权利。

In that way, the virus could expand its infectious empire without destroying perfectly good viral factories en route. The researchers suspect that other so-called naked or nonenveloped viruses (like the cold virus and the enteroviruses that have lately plagued children in this country and Asia) could likewise spread through unconventional secretion pathways.如此一来，病毒可以在不毁坏极致的病毒工厂的情况下不断扩大传染范围。研究人员推断，其他所谓的裸病毒或无包膜病毒（比如最近后遗症美国及亚洲儿童的发烧病毒和肠道病毒）某种程度需要通过非传统黏液途径传播。

For their part, viruses like Ebola have figured out how to slip in and out of cells without kicking up a fuss by cloaking themselves in a layer of greasy lipids stolen from the host cell membrane, rather as you might foist a pill down a pets throat by smearing it in butter.埃博拉等病毒早已告诉如何在从宿主细胞的细胞膜中窃取的一层脂质的伏击下悄悄转入、瓦解细胞，就像你用沾上黄油的药片去进食宠物一样。According to Eric O. Freed, the head of the virus-cell interaction section at the National Cancer Institute, several recent technological breakthroughs have revolutionized the study of viruses.美国国家癌症研究所(National Cancer Institute)病毒与细胞对话部门的主管埃里克·O·弗里德(Eric O. Freed)回应，最近几项技术突破使病毒研究再次发生了极大变革。Advances in electron microscopy and super-resolved fluorescence microscopy — the subject of this years Nobel Prize in Chemistry — allow scientists to track the movement of viral particles in and between cells, and to explore the fine atomic structure of a virus embraced by an antibody, or a virus clasped onto the protein lock of a cell.电子显微镜和超强高分辨率荧光显微镜的发展使得科学家需要跟踪病毒粒子在细胞内及细胞间的活动，理解被抗体围困的病毒或细胞蛋白融合位上的病毒的细致原子结构。

今年的诺贝尔化学奖就授予给了对超强高分辨率荧光显微镜发展作出贡献的科学家。Through ultrafast gene sequencing and targeted gene silencing techniques, researchers have identified genes critical to viral infection and drug resistance. Weve discovered viruses we didnt even know existed, Dr. Freed said. And that could prove important to detecting the emergence of a new lethal strain.研究人员早已通过较慢基因测序及靶基因绝望技术，确认了对病毒感染及抗药性至关重要的基因。

弗里德博士说道，“我们找到了之前不告诉的病毒。”事实可能会证明，这对新的可怕病毒的观测十分最重要。Viruses are also notable for what they lack. They have no ribosomes, the cellular components that fabricate the proteins that do all the work of keeping cells alive.病毒还有一个显著特点，它们缺乏一些东西。

它们没核糖体——制备蛋白的细胞器，而蛋白是保持细胞存活的物质。Instead, viruses carry instructions for co-opting the ribosomes of their host, and repurposing them to the job of churning out capsid and other viral proteins. Other host components are enlisted to help copy the instructions for building new viruses, in the form of DNA or RNA, and to install those concise nucleic texts in the newly constructed capsids.但病毒不会装载利用其宿主核糖体的指令，转变它们的用途，使它们制备大量衣壳及其他病毒蛋白。

宿主细胞的其他部分则被用作协助拷贝发展新病毒的指令——其形式展现出为DNA或RNA，并将这些非常简单的核素移往在新的制备的衣壳中。Viruses are almost miraculously devious, Dr. Freed said. Theyre just bundles of protein and nucleic acid, and theyre able to get into cells and run the show.“病毒极为阴险，”弗里德博士说道。“虽然它们只不过是一堆蛋白和核酸，它们却能入侵细胞，掌控细胞。

”On the one hand, theyre quite simple, Dr. Enquist said. On the other hand, they may be the most highly evolved form of genetic information on the planet.“一方面，它们非常简单，恩奎斯特博士说道。“另一方面，它们有可能是地球上演化程度最低的遗传信息形式。Viruses also work tirelessly to evade the immune system that seeks to destroy them. One of the deadliest features of the Ebola virus is its capacity to cripple the bodys first line of defense against a new pathogen, by blocking the release of interferon.病毒还坚持不懈地逃离着企图毁坏它们的免疫系统。

埃博拉病毒需要妨碍干扰素的获释，突破人体防卫新的病菌的第一道防线，这也是该病毒最可怕的特征之一。That gives the virus a big advantage to grow and spread, said Christopher F. Basler, a professor of microbiology at Mount Sinai School of Medicine.西奈山医学院(Mount Sinai School of Medicine)微生物学教授克里斯托弗·F·巴斯纳(Christopher F. Basler)说道，“这给了这种病毒极大的优势，有助它的快速增长和传播。”At the same time, said Aftab Ansari of Emory University School of Medicine, the virus disables the bodys coagulation system, leading to uncontrolled bleeding. By the time the body can rally its second line of defense, the adaptive immune system, it is often too late.埃默里大学医学院的(Emory University School of Medicine)的阿夫塔卜·安萨里(Aftab Ansari)回应，与此同时，病毒破坏了人体炎症系统，造成人体不能掌控地发炎。

等到人体筑成第二道防线——适应性免疫系统时，一般来说为时已晚。Yet the real lethality of Ebola, Dr. Ansari said, stems from a case of mistaken location, a zoonotic jump from wild animal to human being. The normal host for Ebola virus is the fruit bat, in which the virus replicates at a moderate pace without killing or noticeably sickening the bat.但安萨里博士回应，埃博拉病毒确实的杀伤力源自错放了方位，从野生动物横跨物种病毒感染了人类。埃博拉病毒的宿主一般来说是果蝠，病毒在不使果蝠丧生或显著患病的情况下急剧拷贝。

A perfect parasite is able to replicate and not kill its host, Dr. Ansari said. The Ebola virus is the perfect parasite for a bat.“极致的宿主生物需要拷贝，且不杀掉宿主，”安萨里说道。“埃博拉病毒是蝙蝠身上的极致寄生物。

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