2006年VOA标准英语-Scientists May Have Vaccine for Deadly Las

By Zulima Palacio
Washington, DC
03 February 2006
 
watch Lassa report

When it comes to dangerous jobs, we usually think of things like racing¹ cars, testing explosives or exploring space.  Actually, one of the most dangerous jobs is in a type of laboratory known as "biosafety level four".  That is where scientists research unknown and deadly viruses, including Lassa fever. It can be fatal, is endemic in West Africa, and is on the U.S. list of potential bioterrorism weapons.  Amy Katz narrates² the report.

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Researcher working in lab  
  

Researching and testing a virus that has no cure requires extreme precautions.  In San Antonio, Texas is one of the most secure laboratories in the U.S: a “safety level four” facility.   There are only a few of them and they are expensive and complex to operate. The most dangerous viruses associated with bio terrorism, such as Ebola, Anthrax, and Lassa fever, have been studied here.   Any animals used in tests must be euthanized and cremated³ to avoid accidental release of viruses. 

Dr. Jean Patterson is the Chair of the Department of Virology and Immunology here at the Southwest Foundation for Biomedical Research.

"Safety level four is a type of laboratory where you work with things for which there is no vaccine⁴, no treatment, is potentially lethal⁵ and can be transmitted in the lab."

"The procedure for dressing⁶ up and going in takes about 30 minutes,” says Dr. Ricardo Carrion⁷, a staff scientist at the Virology Department. “By the time you put your suit on, and check to make sure there are no holes in it, and enter, is a rather long period.  Once you get in there, it takes another 20-30 minutes to come out.  It takes about seven minutes to leave the laboratory but then you have to take a physical shower and get dressed.  So basically once you are in there you want to stay in there until you are done with your experiments."

Dr. Carrion explains that in order to avoid doing that constantly, they use surveillance cameras to watch what's going on in the lab.

"Instead of going in four times a day, we're able to look at the animals directly to see how they're doing."

These guinea pigs are being use to test a potential vaccine for Lassa fever, not a common illness in most places, but endemic in West Africa, where every year it affects between 300,000 and 500,000 people.  A rodent⁸ immune to the virus transmits it.  Lassa fever is often misdiagnosed and mistreated.  Most of the time the human immune system can deal with it.  But if it develops into hemorrhagic fever, it can be deadly.

"About 15 percent of those that get hemorrhagic fever end up dying, whereas with women, if they are infected and they are pregnant, it is about 60 percent," says Dr. Carrion.

So far, the test of the vaccines⁹ originally developed by the University of Maryland, but never before tested, is showing promising¹⁰ results. According to Dr. Carrion, animals are given the vaccine and then infected with the Lassa fever virus.

"We took this virus and we vaccinated¹¹ guinea pigs and 30 days after we vaccinated them we challenge them with a lethal dose of Lassa virus, actually 1,000 times what would take to require to make an animal sick. And we found that these animals, not only didn't get sick, but in their tissue level there was no damage. We look at enzyme¹² levels, that indicate liver damage, we didn't see any of those in the blood stream throughout the infection"

Once the studies with guinea pigs are finished, they will move on to monkeys.  If and when the vaccine proves to be safe and effective in monkeys, there will be human trials, says Dr. Patterson. 

"Assuming we can make it work in a primate¹³, non-human model and we can get a license¹⁴ from a large pharmaceutical¹⁵ company, I would say in five years, when it could start being put into humans," she said.

West Africa could be the first beneficiary of the vaccine.  But the U.S. government, which is financing the research, also wants to maintain a reserve in case of a bio-terror attack using the Lassa virus.  If everything goes well, scientists at the Southwest Foundation eventually plan to produce a dual¹⁶ vaccine for yellow fever and Lassa fever.

1 racing   

n.竞赛，赛马；adj.竞赛用的，赛马用的

参考例句：

• I was watching the racing on television last night.昨晚我在电视上看赛马。
• The two racing drivers fenced for a chance to gain the lead.两个赛车手伺机竞相领先。

2 narrates   

v.故事( narrate的第三人称单数 )

参考例句：

• It narrates the unconstitutional acts of James II. 它历数了詹姆斯二世的违法行为。 来自辞典例句
• Chapter three narrates the economy activity which Jew return the Occident. 第三章讲述了犹太人重返西欧后的经济活动。 来自互联网

3 cremated   

v.火葬，火化（尸体）( cremate的过去式和过去分词 )

参考例句：

• He wants to is cremated, not buried. 他要火葬，不要土葬。 来自《简明英汉词典》
• The bodies were cremated on the shore. 他们的尸体在海边火化了。 来自辞典例句

4 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。

5 lethal   

adj.致死的；毁灭性的

参考例句：

• A hammer can be a lethal weapon.铁锤可以是致命的武器。
• She took a lethal amount of poison and died.她服了致命剂量的毒药死了。

6 dressing   

n.(食物)调料；包扎伤口的用品，敷料

参考例句：

• Don't spend such a lot of time in dressing yourself.别花那么多时间来打扮自己。
• The children enjoy dressing up in mother's old clothes.孩子们喜欢穿上妈妈旧时的衣服玩。

7 carrion   

n.腐肉

参考例句：

• A crow of bloodthirsty ants is attracted by the carrion.一群嗜血的蚂蚁被腐肉所吸引。
• Vultures usually feed on carrion or roadkill.兀鹫通常以腐肉和公路上的死伤动物为食。

8 rodent   

n.啮齿动物；adj.啮齿目的

参考例句：

• When there is a full moon,this nocturnal rodent is careful to stay in its burrow.月圆之夜，这种夜间活动的啮齿类动物会小心地呆在地洞里不出来。
• This small rodent can scoop out a long,narrow tunnel in a very short time.这种小啮齿动物能在很短的时间里挖出一条又长又窄的地道来。

9 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

10 promising   

adj.有希望的，有前途的

参考例句：

• The results of the experiments are very promising.实验的结果充满了希望。
• We're trying to bring along one or two promising young swimmers.我们正设法培养出一两名有前途的年轻游泳选手。

11 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？

12 enzyme   

n.酵素，酶

参考例句：

• Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度，酶分子将会展开。
• An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。

13 primate   

n.灵长类（目）动物，首席主教；adj.首要的

参考例句：

• 14 percent of primate species are highly endangered.14%的灵长类物种处于高度濒危状态。
• The woolly spider monkey is the largest primate in the Americas.绒毛蛛猴是美洲最大的灵长类动物。

14 license   

n.执照，许可证，特许；v.许可，特许

参考例句：

• The foreign guest has a license on the person.这个外国客人随身携带执照。
• The driver was arrested for having false license plates on his car.司机由于使用假车牌而被捕。

15 pharmaceutical   

adj.药学的，药物的；药用的，药剂师的

参考例句：

• She has donated money to establish a pharmaceutical laboratory.她捐款成立了一个药剂实验室。
• We are engaged in a legal tussle with a large pharmaceutical company.我们正同一家大制药公司闹法律纠纷。

16 dual   

adj.双的；二重的，二元的

参考例句：

• The people's Republic of China does not recognize dual nationality for any Chinese national.中华人民共和国不承认中国公民具有双重国籍。
• He has dual role as composer and conductor.他兼作曲家及指挥的双重身分。