VOA慢速英语2011--Anthrax Has Been Widely Feared Since the 2001 Anthrax Attacks in the United

SCIENCE IN THE NEWS - Anthrax Has Been Widely Feared Since the 2001 Anthrax Attacks in the United

 

BARBARA KLEIN: This is SCIENCE IN THE NEWS, in VOA Special English. I’m Barbara Klein.

CHRISTOPHER CRUISE: And I’m Christopher Cruise. Today we tell about the deadly disease anthrax.

(MUSIC)

BARBARA KLEIN: Ten years have passed since letters containing anthrax bacteria passed through the mail in the United States. The anthrax particles looked like harmless white powder. But the bacteria killed five people.

No one knew who mailed the letters. News organizations and congressional offices were the main targets. And, the anthrax particles also found their way to the home of a ninety-four-year-old woman.

Years later, federal investigators¹ named a scientist, Bruce Edwards Ivins, as the only suspect in the murders. He was an anthrax expert who worked at the biological defense² center in Maryland, where the bacteria was kept. The government was preparing to charge him when he killed himself in two thousand eight.

Biohazard investigators outside the Dirksen Senate office building in Washington in October of 2001

CHRISTOPHER CRUISE: Recently, an investigation³ requested by Congress suggested that Bruce Ivins may have been falsely suspected. Other investigators and news organizations also have studied the case and questioned the evidence against Mr. Ivins.

Government lawyers say there is no reason for debate. The lawyers say they know they found the right person. But questions about the case have caused concern among some people. They believe that if Bruce Ivins was innocent, the person who sent the letters containing anthrax might still be free.

BARBARA KLEIN: Anthrax also is the subject of another current debate. An expert advisory⁴ committee has proposed testing a vaccine⁵ against anthrax on children. Currently, medical workers are giving the vaccine to some adults. But it has not been tested on children. The goal of the possible testing would be to learn if children could be protected from the disease in the event of a terrorist attack.

A photograph of the letter containing anthrax that was sent to Senate Majority Leader Tom Daschle

The National Biodefense Science Board proposed the testing to the United States Department of Health and Human Services. The Board noted⁶ the ethical⁷ questions involved. But it said it would suggest approval of the tests if those questions could be settled.

Some health-activist groups and others immediately protested the possible tests. The Obama Administration has said the issue will remain under study.

CHRISTOPHER CRUISE: The anthrax vaccine has been available for years on a limited basis. It is given mainly to members of the armed forces. More than two million armed forces members have had the vaccine. It is generally considered safe. But there have been protests about unexpected side effects. People who work with animals also can be vaccinated⁸ against anthrax.

Anthrax cannot be passed from one person to another. However, anthrax affects cattle and other creatures that eat plants. It also can affect people who deal with infected animals or animal products.

A microscopic9 view of stained anthrax bacteria

Anthrax is found naturally in the environment. It is caused by the bacterium¹⁰ Bacillus anthracis (pron., an THRA sis). The bacteria have spores¹² or protective coverings. Spores are like seeds. They can live for hundreds of years in the soil. They can survive through severe heat, dry weather, and other extreme conditions.

(MUSIC)

BARBARA KLEIN: Anthrax can be found anywhere in the world. It is most common in developing countries. Animals can get the bacteria while eating plants. That can loosen anthrax spores in the soil. The animal eats or breathes in the spores and may become infected. But a vaccine can protect animals.

In people, the disease can appear in three forms: cutaneous anthrax, intestinal¹³ anthrax and inhalation anthrax.

Cutaneous anthrax is the most common kind of infection. People can become infected this way if the bacteria enter through a cut in the skin. The disease is most often found among people who work with infected animals or animal products. Cutaneous anthrax causes a painful, black area on the skin. However, it rarely causes death.

CHRISTOPHER CRUISE: Intestinal anthrax results from eating infected meat. It can cause high body temperature, stomach pain and expulsion of food from the stomach. It often can be cured.

The most severe form of the disease is inhalation anthrax. This happens when a person breathes the spores into the lungs. Inhalation anthrax is most often found among people who work with animal hair and wool in areas where the disease affects animals.

Inhalation anthrax is deadly if a person breathes in thousands of extremely small spores. Large spores may get caught in the nose or throat, where they are less dangerous. But the small spores can travel to the lungs.

BARBARA KLEIN: The body’s natural defenses against disease attack some spores. But they carry others to the lymph nodes in the chest. Once there, the spores change into a deadly form. The bacteria grow and spread to the rest of the body.

This may take a day, a week or up to two months. As infection spreads to the rest of the body, the bacteria produce poisons that enter the blood. These poisons can cause a build-up of fluids in the lung, tissue destruction and death.

CHRISTOPHER CRUISE: Doctors treat infected people with antibiotic¹⁴ medicines. Antibiotics¹⁵ have proven effective in fighting the disease in most cases. They can treat the disease if it is discovered early. The antibiotics ciprofloxacin penicillin¹⁶ and doxycycline are all effective treatments.

An anthrax infection is especially dangerous because people do not know they have been infected until symptoms appear. Signs of the disease usually appear within a few days. Chest X-rays can help doctors tell if a person has inhaled¹⁷ anthrax.

Early symptoms are similar to the disease influenza¹⁸. They may include high body temperature, muscle pain and a cough. These are usually followed by severe breathing problems and death if the disease is not treated.

BARBARA KLEIN: Anthrax spores are hard to kill. Antibiotics halt the development of the disease by fighting the bacteria as they grow from the spores. However, antibiotics do not fight the poisons that the bacteria produce.

To work best, the antibiotics need to be active in the blood for as long as spores might be present in the lungs or in other places in the body. Health officials say people should take antibiotics for an extended period to treat or protect against anthrax infection.

(MUSIC)

CHRISTOPHER CRUISE: Anthrax is considered a major threat because of its ability to be used as a biological weapon. Biological weapons are living microorganisms. Biological and chemical agents are most effective when they are spread into the air. These agents are often placed in bombs or artillery¹⁹ shells that are designed to explode into the air and spread poisons over an enemy.

Many biological and chemical agents have no color, smell or taste. So an attack could take place without the victims knowing it.

Experts say anthrax is one of the easiest biological agents to manufacture. It can be grown in a laboratory. It spreads easily through the air over a large area. It can be made into a form that is easily inhaled. It is easily stored and is dangerous for a long period of time. It also costs very little to make.

BARBARA KLEIN: Anthrax has been used in laboratory experiments for more than one-hundred years. Many scientists have used anthrax for traditional research purposes. The bacteria also have been genetically²⁰ changed for biological weapons research. The United States and countries of the former Soviet²¹ Union have experimented with anthrax in their biological weapons programs.

Anthrax spores in nature stick together in particles too large to be breathed in. Experts say that the individual anthrax spore¹¹ is extremely small, about one micron wide. For example, two-thousand spores lined up would measure only two millimeters. Particles that are five microns or bigger are usually trapped in the upper part of the respiratory system.

To be an effective weapon, anthrax spores are reproduced to be smaller than five microns. Experts say making such anthrax spores requires special laboratory equipment and a great deal of skill. And to many people, that is a very good thing.

(MUSIC)

CHRISTOPHER CRUISE: This SCIENCE IN THE NEWS program was written by Cynthia Kirk and Jerilyn Watson. I’m Christopher Cruise.

BARBARA KLEIN: And I’m Barbara Klein. You can find transcripts²², MP3s and podcasts of our programs at voanews.cn. And you can find us on Twitter and YouTube at VOA Learning English. Join us again next week for more news about science in Special English on the Voice of America.

1 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

2 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

3 investigation   

n.调查，调查研究

参考例句：

• In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
• He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。

4 advisory   

adj.劝告的，忠告的，顾问的，提供咨询

参考例句：

• I have worked in an advisory capacity with many hospitals.我曾在多家医院做过顾问工作。
• He was appointed to the advisory committee last month.他上个月获任命为顾问委员会委员。

5 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

6 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

7 ethical   

adj.伦理的，道德的，合乎道德的

参考例句：

• It is necessary to get the youth to have a high ethical concept.必须使青年具有高度的道德观念。
• It was a debate which aroused fervent ethical arguments.那是一场引发强烈的伦理道德争论的辩论。

8 vaccinated   

[医]已接种的，种痘的，接种过疫菌的

参考例句：

• I was vaccinated against tetanus. 我接种了破伤风疫苗。
• Were you vaccinated against smallpox as a child? 你小时候打过天花疫苗吗？

9 microscopic   

adj.微小的，细微的，极小的，显微的

参考例句：

• It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
• A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。

10 bacterium   

n.(pl.)bacteria 细菌

参考例句：

• The bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
• A bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。

11 spore   

n.(无花植物借以繁殖的)孢子，芽胞

参考例句：

• A spore can quickly spread and form a mould.一个孢子能迅速蔓延并形成霉。
• The cation penetrates the spore.这种阳离子能透入孢子。

12 spores   

n.（细菌、苔藓、蕨类植物）孢子( spore的名词复数 )v.（细菌、苔藓、蕨类植物）孢子( spore的第三人称单数 )

参考例句：

• Ferns, mosses and fungi spread by means of spores. 蕨类植物、苔藓和真菌通过孢子传播蔓生。
• Spores form a lipid membrane during the process of reproducing. 孢于在生殖过程中形成类脂膜。 来自英汉非文学 - 生命科学 - 预防生物武器

13 intestinal   

adj.肠的；肠壁；肠道细菌

参考例句：

• A few other conditions are in high intestinal obstruction. 其它少数情况是高位肠梗阻。 来自辞典例句
• This complication has occasionally occurred following the use of intestinal antiseptics. 这种并发症偶而发生在使用肠道抗菌剂上。 来自辞典例句

14 antibiotic   

adj.抗菌的；n.抗生素

参考例句：

• The doctor said that I should take some antibiotic.医生说我应该服些用抗生素。
• Antibiotic can be used against infection.抗菌素可以用来防止感染。

15 antibiotics   

n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )

参考例句：

• the discovery of antibiotics in the 20th century 20世纪抗生素的发现
• The doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

16 penicillin   

n.青霉素，盘尼西林

参考例句：

• I should have asked him for a shot of penicillin.我应当让他给我打一针青霉素的。
• Penicillin was an extremely significant medical discovery.青霉素是极其重要的医学发现。

17 inhaled   

v.吸入( inhale的过去式和过去分词 )

参考例句：

• She closed her eyes and inhaled deeply. 她合上双眼，深深吸了一口气。
• Janet inhaled sharply when she saw him. 珍妮特看到他时猛地吸了口气。 来自《简明英汉词典》

18 influenza   

n.流行性感冒，流感

参考例句：

• They took steps to prevent the spread of influenza.他们采取措施
• Influenza is an infectious disease.流感是一种传染病。

19 artillery   

n.(军)火炮，大炮；炮兵(部队)

参考例句：

• This is a heavy artillery piece.这是一门重炮。
• The artillery has more firepower than the infantry.炮兵火力比步兵大。

20 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

21 Soviet   

adj.苏联的，苏维埃的；n.苏维埃

参考例句：

• Zhukov was a marshal of the former Soviet Union.朱可夫是前苏联的一位元帅。
• Germany began to attack the Soviet Union in 1941.德国在1941年开始进攻苏联。

22 transcripts   

n.抄本（ transcript的名词复数 ）；转写本；文字本；副本

参考例句：

• Like mRNA, both tRNA and rRNA are transcripts of chromosomal DNA. tRNA及rRNA同mRNA一样，都是染色体DNA的转录产物。 来自辞典例句
• You can't take the transfer students'exam without your transcripts. 没有成绩证明书，你就不能参加转学考试。 来自辞典例句