Mad Cow Disease
74 疯牛病及其最新的检验方法
DATE=7-24-01
TITLE=SCIENCE IN THE NEWS #2134 - Mad Cow Disease 1
BYLINE=Nancy Steinbach, George Grow
VOICE ONE:
This is Sarah Long.
VOICE TWO:
And this is Steve Ember with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science.
Today, we tell about a disease in cows that can spread to other animals and to people. We also tell about recent scientific progress in developing a test for the disease.
(THEME)
VOICE ONE:
The cattle disease is (1)bovine spongiforn encephalopathy. It causes holes to develop in the brain. Cattle act strangely before they die. So it is known as Mad Cow Disease.
B-S-E first (2)appeared in Britain in Nineteen-Eighty-Five, and has spread across much of Europe. All animals known to have the disease since that time have been found in Europe or (3)imports from Europe.
Scientists believe that eating (4)infected beef from a cow suffering B-S-E causes a (5)similar disease in people. This deadly disease is called Creutzfeldt-Jakob Disease, or C-J-D. It cannot be cured. C-J-D is (6)rare. It usually (7)affects people sixty-five years old or older. More than one-hundred people in Europe have died or are dying 2 from it. Most of the (8)victims live in Britain.
VOICE TWO:
Animal health experts recently met in Paris, France, to (9)discuss mad cow disease.
They said more than thirty countries have (10)banned the import of meat, bone meal and live cattle from western Europe. They said countries can be considered at (11)risk for B-S-E if they imported such products from Western Europe during the past twenty years. They said parts of Eastern Europe, Asia and the Middle East are at increased risk.
The officials also (12)urged countries to (13)approve (14)measures to control the killing 3 of animals for food. They say this would reduce the chance of infected meat being sold as food for people. They also said the human food supply should not include the animal parts thought most likely to carry the disease, such as the head and the (15)spinal cord 4.
The European Union now (16)requires that all animals over thirty months old be tested for mad cow disease when they are killed. The idea is that older animals are likely to have more (17)severe infections that are the greatest danger to people.
VOICE ONE:
American officials have taken steps to (18)prevent Mad Cow Disease from entering the United States. The government (19)restricts imports of cows and other animals from countries where B-S-E exists. Imports of some feed products from such areas also are restricted 5. Feed (20)containing animal remains 6 is (21)suspected of causing the disease. American officials say more than two-hundred-fifty experts know how to recognize foreign animal diseases 7, (22)including B-S-E. (23)Information about the disease has been (24)provided to (25)federal 8 and state (26)agencies, laboratories 9 and some colleges.
American officials say they are inspecting animals for signs of B-S-E. Federal (27)inspectors are examining all cows raised for meat. They examine the animals for (28)disorders of the central nervous system. Any animal showing signs of such a disorder 10 is destroyed. The meat is not (29)permitted for use as human food. The brains of these animals are sent to the Agriculture Department for (30)additional tests.
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VOICE TWO:
The only sure way to tell if an animal has B-S-E is to test a brain sample after it has been killed. Now, (31)Israeli scientists say they have discovered the (32)substance (33)responsible for mad cow disease in the (34)liquid waste of animals and people.
Scientists believe B-S-E is caused by a kind of infectious 11 (35)particle known as a prion (PREE-on). Prions are (36)proteins. They do not contain any (37)genetic 12 material so they cannot make copies of themselves. This makes them different from all other known infectious agents such as (38)bacteria, (39)viruses, fungi 13 and (40)parasites.
Prions are found naturally in brain cells of people and animals. They do no harm. Sometimes, however, one changes shape. Other proteins known as (41)enzymes 14 can destroy normal proteins. But they cannot destroy changed prions.
VOICE ONE:
A few years ago, scientist Stanley Prusiner showed how these changed prions act on (42)surrounding normal prions to change them too. More and more prions change, until the changed ones are spread throughout the brain. This kills brain (43)tissue and causes human (44)spongiform brain diseases, including Creutzfeldt-Jakob disease.
Doctor Prusiner also showed that prion disease could move from one kind of animal to another. For example, he showed that people could develop C-J-D by eating meat from cows infected with B-S-E. Doctor Prusiner won the Nobel Prize for Medicine in Nineteen-Ninety-Seven for his work.
VOICE TWO:
Ruth Gabizon was one of the researchers who worked with Doctor Prusiner. She continued her own research on human spongiform brain disease at the Hadassah University Hospital in (45)Jerusalem, Israel. She was studying the part prions play in causing genetic Creutzfeldt-Jakob disease. This kind of C-J-D affects Jews whose families were from (46)Libya.
The researchers on her team were looking for (47)evidence of changed prions in liquid waste or (48)urine. They studied the urine of small laboratory 15 animals called (49)hamsters, cattle and people. They tested the urine from animals and people infected with known prion diseases and from those who were healthy.
The (50)kidneys (51)contain (52)urea, a substance that (53)interferes with protein changing but does not destroy the proteins. The researchers suspected the prions might be changed by urea.
VOICE ONE:
To test this idea, they put the urine samples from the animals and people into a machine that (54)removes urea. This permitted the proteins to go back to their normal shapes. These proteins were then (55)treated with enzymes that destroy normal proteins but not prions.
All the proteins were destroyed in the urine from healthy animals and people. But one protein (56)survived in animals and people with prion diseases. The researchers said the (57)presence of such a protein in urine is the way to tell if prion disease is present. The Israeli scientists also infected some hamsters with prion disease. Tests of their urine showed the changed protein several weeks before signs of the disease first appeared. VOICE TWO:
A report of the Israeli research group's experiments will be (58)published in the Journal 16 of Biological Chemistry in September. However, the (59)publication has already placed the research on its Internet web site.
Scientists who have seen the research say the experiment was simple and the results should easily be (60)confirmed. Many laboratories all over the world are reportedly already trying to do this. If the results are confirmed, the new test could be used on groups of cattle. It could save uninfected cattle that are now killed after an infected animal is found.
(MUSIC BRIDGE)
VOICE ONE:
The Israeli scientists say their test will be able to tell which people and animals are infected with spongiform disease before signs appear.
Other scientists say this could help make the blood supply safer around the world. It has not yet been proved that people with C-J-D can spread the disease by giving blood to other people. Yet officials are worried about that (61)possibility. The American Red Cross will not accept blood from people who have lived in Britain for three months or in Europe for six months during the last twenty years.
The (62)proposed test may also help answer questions about sick deer and other wild animals in the western United States and Canada. The animals are (63)suffering a brain condition known as (64)chronic wasting disease. The disease has spread among wild deer and (65)elk 17. Researchers do not know how it is spread. But they say the new test could help discover the answer.
VOICE TWO:
The Israeli scientists recognize that they are attempting to create a test for a disease that cannot be cured. In people, the (66)period of time between infection and the first signs of the Creutzfeldt-Jakob disease may be as long as twenty or thirty years. Would people want to know if they are infected with the disease so many years before they would become sick? That is a question people may have to answer in the future. For now, scientists say the new test may help them learn more about the prions responsible for spongiform disease before and after a person or animal becomes sick.
(THEME)
VOICE ONE:
This SCIENCE IN THE NEWS program was written by George Grow and Nancy Steinbach. It was produced by Caty Weaver 18 with audio 19 assistance 20 by twine 21 carlens . This is Sarah Long.
VOICE TWO: And this is Steve Ember. Join us again next week for more news about science in Special English on the Voice of America.
(1)bovine [ 5bEuvain ] spongiforn encephalopathy [en9sefE`lCpEWI] n.牛海绵状脑病
(2)appear [ E5piE ]vi.出现
(3)import [ im5pC:t ]vt.进口
(4)infect [ in5fekt ]vt.[医]感染
(5)similar [ 5similE ]adj.相似的, 类似的
(6)rare [ rZE ]adj.罕见的
(7)affect [ E5fekt ]vt.影响
(8)victim [ 5viktim ]n.牺牲品
(9)discuss [ dis5kQs ]vt.讨论, 论述
(10)ban [ bB:n ] vt.禁止
(11)risk [ risk ] n.风险
(12)urge [ E:dV ]vt.催促
(13)approve [ E5pru:v ]vt.批准, 通过
(14)measure [ 5meVE ]n.标准
(15)spinal [ 5spainl ]adj.脊骨的, 脊髓的
(16)require [ ri5kwaiE ]vt.需要, 要求, 命令
(17)severe [ si5viE ]adj.严重的, 严峻的
(18)prevent [ pri5vent ]v.预防
(19)restrict [ ris5trikt ]vt.限制
(20)contain [ kEn5tein ]vt.包含
(21)suspect [ sEs5pekt ] v.怀疑
(22)include [ in5 klu:d ]vt.包括, 包含
(23)information [ 7infE5meiFEn ]n.信息
(24)provide [ prE5vaid ]v.供应, 供给
(25)federal [ 5fedErEl ]adj.联邦的
(26)agency [ 5eidVEnsi ]n.代理处
(27)inspector [ in5spektE ]n.检查员, 巡视员
(28)disorder [ dis5C:dE ]n.杂乱, 混乱, 无秩序状态
(29)permit [ pE(:)5mit ]v.许可, 允许, 准许
(30)additional [ E5diFEnl ]adj.另外的, 附加的, 额外的
(31)Israeli [ iz5reili ]adj.以色列共和国的n.以色列共和国民
(32)substance [ 5sQbstEns ]n.物质, 实质
(33)responsible [ ris5pCnsEbl ]adj.有责任的,负责的
(34)liquid [ 5likwid ]n.液体
(35)particle [ 5pB:tikl ]n.微粒
(36)protein [ 5prEuti:n ]n.[生化]蛋白质
(37)genetic [ dVi5netik ]adj.遗传的, 起源的
(38)bacteria [ bAk5tiEriE ]n.细菌
(39)virus [ 5vaiErEs ]n.[微]病毒
(40)parasite [ 5pArEsait ]n.寄生虫
(41)enzyme [5enzaIm]n.[生化]酶
(42)surrounding [ sE5raundiN ] adj.周围的
(43)tissue [ 5tisju: ]n. [生]组织
(44)spongiform [ 5spQNdVifC:m ]adj.海绵状(组织)的
(45)Jerusalem [ dVe5ru:sElEm ]n.耶路撒冷(巴勒斯坦著名古城)
(46)Libya [ 5libiE ]n.利比亚（北非国家）
(47)evidence [ 5evidEns ]n. [物]证据
(48)urine [ 5juErin ]n.尿
(49)hamster [5hAmstE(r)] n.东欧或亚洲产的大颊的鼠类
(50)kidneys [ 5kidniz ]肾形矿脉
(51)contain [ kEn5tein ]vt.包含
(52)urea [ 5juEriE ]n.[化]尿素
(53)interfere [ 7intE5fiE ]vi.干涉
(54)remove [ ri5mu:v ]vt.移开
(55)treat [ tri:t ] vt.对待
(56)survive [ sE5vaiv ]v.幸存
(57)presence [ 5prezns ]n.存在
(58)publish [ 5pQbliF ]v.出版, 刊印
(59)publication [ 7pQbli5keiFEn ]n.出版物
(60)confirm [ kEn5fE:m ]vt.确定
(61)possibility [ 7pCsi5biliti ]n.可能性
(62)propose [ prE5pEuz ]vt.建议
(63)suffer [ 5sQfE ]vt.遭受, 经历
(64)chronic [ 5krCnik ]adj.慢性的
(65)elk [ elk ]n.[动]麋鹿
(66)period [ 5piEriEd ]n.时期adj.过去某段时期的
- The doctors are trying to stamp out the disease.医生正在尽力消灭这种疾病。
- He fought against the disease for a long time.他同疾病做了长时间的斗争。
- He was put in charge of the group by the dying leader.他被临终的领导人任命为集团负责人。
- She was shown into a small room,where there was a dying man.她被领进了一间小屋子，那里有一个垂死的人。
- Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
- Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。
- I wear a safety cord all the time.我一直带着安全绳索。
- I pulled the cord,and I felt a strong jerk.拉住绳索，我强烈的恐惧。
- Speed is restricted to 30 mph in towns. 在城里车速不得超过每小时30英里。
- a restricted range of foods 有限的食物种类
- He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
- The remains of the meal were fed to the dog.残羹剩饭喂狗了。
- Smoking is a causative factor in several major diseases. 抽烟是引起几种严重疾病的病因。
- The illness frequently coexists with other chronic diseases. 这种病往往与其他慢性病同时存在。
- Switzerland is a federal republic.瑞士是一个联邦共和国。
- The schools are screaming for federal aid.那些学校强烈要求联邦政府的援助。
- For, eight years, Marie Curie worked in cold laboratories with poor equipment. 整整八年，居里夫人在设备简陋、冰冷的实验室里做着实验。 来自英汉非文学 - 科学史
- Some commercial laboratories use periodic nitrate tests as guides. 许多商业性的试验室已应用定期的硝态氮分析作为指导。 来自辞典例句
- When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
- It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。
- Influenza is an infectious disease.流感是一种传染病。
- What an infectious laugh she has!她的笑声多么具有感染力啊！
- It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
- Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
- Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
- The lawn was covered with fungi.草地上到处都是蘑菇。
- It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
- Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。
- She has donated money to establish a laboratory.她捐款成立了一个实验室。
- Our laboratory equipment isn't perfect,but we must make do.实验室设备是不够理想，但我们只好因陋就简。
- He kept a journal during his visit to Japan.他在访问日本期间坚持记日记。
- He got a job as editor of a trade journal.他找到了一份当商业杂志编辑的工作。
- I was close enough to the elk to hear its labored breathing.我离那头麋鹿非常近，能听见它吃力的呼吸声。
- The refuge contains the largest wintering population of elk in the world.这座庇护所有着世界上数量最大的冬季麋鹿群。
- She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
- The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。
- Often,the meeting is recorded on audio or video media for later reference.通常这种会议会以视频或者音频形式记录下来，供以后查阅。
- You don't even have to pay for audio programs.你大可不必为自己听这些节目付费。
- She called and called but no one came to her assistance.她叫了又叫，但没有人来帮。
- He will get the great possible assistance.他将获得尽可能大的帮助。