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1918 Flu's Genetic1 Code May Help Fight Bird Flu
1918年的流感病毒基因源代码可能帮助人类抗击禽流感
It was the 20th century's greatest plague. Estimates of the 1918-1919 flu death toll2 range from 20 million to 50 million, more than died in the war that had just preceded it.
The head of the U.S. government's disease tracking agency, Julie Gerberding of the Centers for Disease Control, says hardest hit were the young and productive between 20 and 40 years old.
Julie Gerberding: The 1918 influenza3 virus that caused such global disease spread very rapidly, particularly among healthy people, was very, very virulent4, and certainly circled the globe in record time.
U.S. government and private scientists have now finished a 10-year project to determine the virus' genetic makeup5. They recreated a live virus in a high-security laboratory at the Centers for Disease Control (CDC) by combining fragments from the organism's eight genes6.
Researcher Jeffrey Taubenberger of the Armed Forces Pathology Institute says the genetic scraps7 were gathered from well preserved lung tissue samples taken from victims during autopsies8 87 years ago or, in one case, from a victim exhumed10 from Alaskan permafrost.
Jeffrey Taubenberger: Because influenza viruses were not known to exist in 1918, there were no isolates11 made of this strain of the virus, and so there was actually no way for medical scientists to directly study this influenza virus.
The scientists tested the virus by inserting it into mice, chicken embryos13, and human lung cells. They found that by substituting genes from other flu viruses, they could make it less lethal14.
The research, published in the weekly journals Science and Nature, shows that the 1918 flu virus is more closely related to bird flus than human flus. It has several of the same genetic mutations found in the bird flu strain now spreading in Asia, mutations believed to help the virus replicate16 more efficiently17.
Mr. Taubenberger says this reveals that bird flu viruses can cause serious human infection without first combining with a strain already adapted to people. Some experts have said that effective human transmission might require combination with a human flu.
Jeffrey Taubenberger: We now think that the 1918 virus was an entirely18 avian-like virus that adapted to humans, it is a different situation than the last two pandemics we had, the Asian flu in 1957 and the Hong Kong flu in 1968, which are mixtures in which a human-adapted influenza virus acquired two or three new genes from an avian influenza source. So it suggests that pandemics can form in more than one way, and this is a very important point.
He says it also suggests that the current Asian bird flu, known by its scientific designation H5N1, could evolve into a human killer19 with just a few more mutations that allow it to jump more efficiently among people.
Jeffrey Taubenberger: It suggests to us the possibility that these H5 viruses are actually being exposed to some human adaptive pressures and that they might be acquiring some of these same changes. In a sense, they might be going down a similar path that ultimately led to 1918.
Mr. Taubenberger says if researchers can identify virus components20 that are important in the process of adapting to humans, they could make a list of molecules22 to look for in emerging bird flus that threaten people.
Dr. Gerberding of the Centers for Disease Control says the work will allow new medical therapies to target those molecules.
Julie Gerberding: It is revealing to us some of the secrets that will help us predict and prepare for the next pandemic.
Dr. Gerberding says it is comforting to know that the 1918 virus, now that it has been reconstructed, is susceptible23 to a new vaccine24 U.S. researchers have developed against bird flu. This means it should work against the bird flu, too, if production can be expanded should a pandemic occur.
David McAlary, VOA news, Washington.
注释:
plague [plei^] n. 瘟疫,灾祸
virulent [5virulEnt] adj. 急性的,致死的(病毒、疾病)
genetic [dVi5netik] adj. 起源的
autopsy25 [5C:tEpsi] n. (为查明死因而做的)尸体解剖,验尸
permafrost [5pE:mEfrRst] n. 冰冻层
lethal [5li:WEl] adj. 致命的
mutation15 [mju(:)5teiFEn] n. 变化,突变
replicate [5replikit] v. 复制
designation [7dezi^5neiFEn] n. 名称
therapy [5WerEpi] n. 疗法,治疗
1 genetic | |
adj.遗传的,遗传学的 | |
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2 toll | |
n.过路(桥)费;损失,伤亡人数;v.敲(钟) | |
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3 influenza | |
n.流行性感冒,流感 | |
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4 virulent | |
adj.有毒的,有恶意的,充满敌意的 | |
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5 makeup | |
n.组织;性格;化装品 | |
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6 genes | |
n.基因( gene的名词复数 ) | |
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7 scraps | |
油渣 | |
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8 autopsies | |
n.尸体解剖( autopsy的名词复数 );验尸;现场验证;实地观察 | |
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9 exhume | |
v.掘出,挖掘 | |
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10 exhumed | |
v.挖出,发掘出( exhume的过去式和过去分词 ) | |
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11 isolates | |
v.使隔离( isolate的第三人称单数 );将…剔出(以便看清和单独处理);使(某物质、细胞等)分离;使离析 | |
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12 embryo | |
n.胚胎,萌芽的事物 | |
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13 embryos | |
n.晶胚;胚,胚胎( embryo的名词复数 ) | |
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14 lethal | |
adj.致死的;毁灭性的 | |
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15 mutation | |
n.变化,变异,转变 | |
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16 replicate | |
v.折叠,复制,模写;n.同样的样品;adj.转折的 | |
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17 efficiently | |
adv.高效率地,有能力地 | |
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18 entirely | |
ad.全部地,完整地;完全地,彻底地 | |
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19 killer | |
n.杀人者,杀人犯,杀手,屠杀者 | |
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20 components | |
(机器、设备等的)构成要素,零件,成分; 成分( component的名词复数 ); [物理化学]组分; [数学]分量; (混合物的)组成部分 | |
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21 molecule | |
n.分子,克分子 | |
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22 molecules | |
分子( molecule的名词复数 ) | |
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23 susceptible | |
adj.过敏的,敏感的;易动感情的,易受感动的 | |
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24 vaccine | |
n.牛痘苗,疫苗;adj.牛痘的,疫苗的 | |
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25 autopsy | |
n.尸体解剖;尸检 | |
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