你会得流感吗

　　设想一下，以后可能有一个简单的测试，能让你在嗓子疼、流鼻涕和发烧之前就知道自己感染的到底是流行性感冒还是普通感冒。
　　Imagine that a simple test could tell whether you were going to come down with the flu or a cold even before you get hit by a sore throat, runny nose or fever.

　　杜克大学(Duke University)及多个研究中心的科学家们一直在深入研究病毒是怎样在分子层面将人感染的，以求开发出这样一个预测系统。早期研究结果颇为鼓舞人心，研究人员已经识别了几个可以被病毒激活的基因，但它们仅仅出现于随后出现了流感或感冒症状的病人身上。那些同样暴露于病毒环境但并未因此染病的受测者则没有表现这种基因活性。
　　Scientists at Duke University here and at other research centers have been working to develop such a predictive test by delving deep into the mechanics of how viruses affect people at the molecular level. In early encouraging results, the researchers have identified a handful of genes that are activated by viruses, but only in those people who subsequently came down with flu or cold. Study participants who didn't end up getting sick, even though they were exposed to viruses, didn't exhibit such genetic activity.

　　现在科学家正努力简化这一流程。虽然面前的困难艰巨，但他们的目标是开发出一种个头如黑莓(BlackBerry)般大小的手持检测仪，这样就可以快速检测出谁即将得病。疾病预防控制中心(Centers for Disease Control and Prevention)提供的数据显示，在一个普通的流感季节，几乎每个人都置身于病毒环境，但是只有不超过五分之一的人会最终染病。
　　Now the scientists are trying to simplify the process. Although there are major hurdles ahead, the aim is to develop a portable device, about the size of a BlackBerry, that can quickly determine if someone is on the way to being sick. In a normal flu season, nearly everyone is exposed to influenza viruses, but no more than 20% of the population contracts the illness, according to the Centers for Disease Control and Prevention.

　　现在的测试只能在人们生病后确认他们所感染的病毒或细菌的类型。此类旨在明确病原体的化验往往不能及时在病情诊断中发挥作用。其结果是，医生开出的药可能不对症。以肺炎为例，它即可能是因为病毒感染也可能因为细菌感染而引起，结果大多数病人都不加区分地接受了抗生素治疗。
　　Current tests can detect only what type of virus or bacteria people are infected with after they get sick. Such tests, which seek to detect the actual pathogen, are often too slow to provide diagnoses in a timely manner. As a result, doctors may end up prescribing drugs that aren't needed. Pneumonia, for instance, can be caused by either a virus or bacteria, but most patients get antibiotics in any case.

　　为了尽早确诊，科学家们需要知道症状出现前身体的状况。神经学家凌(Ling)上校说，我们假定身体在发烧、寒战之前就已经在分子层面出现改变，因此我们需要识别那些能预示人即将生病的化学分子出现的改变。
　　To detect illness earlier, scientists need to find out what goes on in the body before symptoms occur. 'We make the assumption that the body will change on the molecular level in advance of fever [and] chills,' says Col. Ling, who is also a neurologist. 'So we needed to identify those chemical molecular changes that say you are going to be sick,' he says.

　　杜克大学染色体医学中心主任金斯博格(Geoffrey Ginsburg)说他的团队从2006年起就开始联手弗吉尼亚大学(University of Virginia)、密歇根大学(University of Michigan)以及美国国家基因组资源中心(National Center for Genomic Resources)的科学家们研究这一课题。去年，这些研究人员对57名志愿者进行了三项研究。这些志愿者分别通过鼻腔感染了感冒病毒、流感病毒和呼吸道合胞病毒(Respiratory Syncytial Virus)，后者主要感染幼儿，症状类似感冒，程度轻重均有。
　　Geoffrey Ginsburg, director of Duke's Center for Genomic Medicine, says his team, along with scientists at the University of Virginia, University of Michigan and the National Center for Genomic Resources, began work on the project in 2006. Last year, the researchers conducted three studies with a total of 57 volunteers. The participants were infected through the nose with either a cold virus, an influenza virus or a respiratory syncytial virus, which causes an illness, especially in young children, that often resembles a moderate to severe cold.

　　研究人员在试验开始前就采集了受测者的血样、鼻涕、尿液和呼气样本，并在随后数次取样，以获基线数据。研究者从志愿者血液中提取了核糖核酸(RNA)，以评估人体内部逾两万个基因中是否有一些因病毒入侵而发生了改变。
　　Researchers took blood, nasal fluid, urine and exhaled-breath samples of the participants before the studies began and at several later points, to get base-line data. RNA, which is genetic material involved with making proteins in the body, was extracted from participants' blood to assess whether any of the more than 20,000 genes in the human body underwent any changes in response to the viral exposure.

　　最后有28名研究志愿者生病，研究人员发现大约有30个基因对病毒感染做出了反应。这些基因变化在病人接触病毒后大约40小时就可以被检测出来，此时距病人出现症状还有超过24小时时间。另外29人没有任何症状，他们身上的对应基因也没有出现改变。
　　Among the 28 study participants who ended up getting sick, researchers found a set of about 30 genes that were turned on in response to having been infected with a virus. The changes in the genes became noticeable about 40 hours after people were exposed to the viruses, and more than a day before they showed signs of being sick. In the 29 people who never developed symptoms, there were no changes to the group of genes.

　　金斯博格说，研究人员把这30个基因称为急性呼吸道病毒信号，它们大多属于人体的免疫系统。金斯博格说，这些基因的功能就是在病原体侵袭时变得活跃起来，以抵御病毒和其他类型的感染。虽然在研究中上述三类病毒激活这些响应基因，但科学家仍在仔细梳理这些数据，看看它们能否区别出这些病原体。这些研究结果发表于9月份的医学杂志《细胞宿主与微生物》(Cell Host & Microbe)上。
　　Dr. Ginsburg says the 30 genes, which researchers call the acute respiratory viral signature, are for the most part involved with the body's immune system. He says these genes are designed to become active when exposed to a pathogen in order to fight a virus or other type of infection. Although all three virus types used in the study activated the genes, scientists are continuing to comb through the data to determine if there is a way to distinguish one pathogen from another. The findings were reported in the journal Cell Host & Microbe in September.

　　金斯博格说，我们希望每种病毒都有自己可以识别的基因指纹。如果这样，科学家们就可以为流感开发出一套专用检测系统；流感病毒引起的病症要比普通感冒严重。
　　'We hope each virus has its own genetic fingerprint,' Dr. Ginsburg says. If so, scientists could seek to develop a test specifically for the flu, which causes more severe illness than the viruses responsible for the common cold.

　　Darpa为这一项目的初期研究投资了约500万美元。9月份，五角大楼研究部门另为杜克大学拨款1,950万美元，用于开发基于上述基因发现的诊断测试。
　　Darpa invested about $5 million in the project's initial studies. In September, the Pentagon research arm granted Duke another $19.5 million to develop a diagnostic test based on the genetic findings.

　　但是这里面仍有很大的障碍。现有的检测基因改变的方法往往需要数天或数周。但是凌上校说，为了能使得这项测试为军方所用，测试时间需缩短至2个小时左右。
　　But there are big hurdles. Current methods to detect gene changes usually take days or even weeks. But Col. Ling says that for the test to be useful to military medical personnel, it would need to be done in about two hours.

　　开发适用仪器的工作尚处初级阶段。杜克大学普莱特工程学院(Pratt School of Engineering)负责研究的高级副院长爱普尔•布朗(April Brown)主导了上述三项研究中的一项，以期设计出检测速度快、手提式的病毒检测仪。布朗和她的团队正在制作若干生物传感器的原型机，专门监测上述30个对病毒有反应的基因是否出现任何变化。
　　The work to develop a usable device is in the preliminary stages. April Brown, the senior associate dean for research at Duke's Pratt School of Engineering, is heading one of three research efforts at the engineering school to design a viral test that is both portable and quick. She and her team are building prototypes of biosensors that are designed to measure any changes among the 30 genes found to be involved with viral illness.

　　金斯博格预计，开发病毒预测的努力也会加速新型抗病毒药物的研发，因为研究人员对上呼吸道感染响应基因有了更深入的了解。这一调查还有助于确定现有药品的最佳治疗方案。目前只有两类得到普遍应用的抗流感药：罗氏公司(Roche Holding)的达菲(Tamiflu)和葛兰素史克(Glaxosmithkline)的瑞乐沙(Relenza)。
　　Dr. Ginsburg expects efforts to develop a new predictive viral test will also speed the development of new antiviral drugs as researchers learn more about the genes that become involved as people get sick with an upper respiratory virus. The research also could help determine the best course of treatment with drugs already on the market. Only two drugs are widely used to treat influenza today -- Roche Holding AG's Tamiflu and GlaxoSmithKline PLC's Relenza.