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(单词翻译:双击或拖选)
SCIENCE IN THE NEWS - A Drug to Protect Against Bird Flu Succeeds in First Tests
By Rochelle Gollust,Jerilyn Watson
Broadcast: Tuesday, August 16, 2005
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VOICE ONE:
This is SCIENCE IN THE NEWS in VOA Special English. I'm Barbara Klein.
VOICE TWO:
And I'm Bob Doughty1. In our program this week, we will talk about the successful effort to produce an exact copy of a dog. Also, scientists say the world's oceans have fewer kinds of fish than they did fifty years ago. We will tell you about the findings.
VOICE ONE:
But first, we will report on human tests of a new protective medicine, or vaccine2.
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VOICE ONE:
American government scientists say they have successfully tested a vaccine that protects people against avian influenza4, or bird flu.
The scientists say they believe the vaccine can protect against the bird flu virus that is spreading in Asia and Russia. This virus is known as h-five-n-one.
Anthony Fauci of the National Institutes of Health announced the test results. He is director of the National Institute of Allergy5 and Infectious Diseases.
Doctor Fauci said the new vaccine could be used in an emergency. But he noted6 that additional tests and government approval are needed before the vaccine could be offered to the public. He also said one important issue is if the medical industry can make enough vaccine to meet the possible demand.
VOICE TWO:
The new vaccine is meant to protect people against infection, not to treat those who are sick. The vaccine cannot cause bird flu because it is made from killed viruses.
Doctor Fauci said the first tests showed the medicine produced strong protection among the small group of healthy adults who received it. He said more tests would be done on other people, older adults, and children during the next several months. Doctor Fauci said he believed the planned tests would confirm the success of the first tests. More tests would also answer remaining questions such as how much of the vaccine is needed for protection.
VOICE ONE:
American government scientists and others developed the vaccine. It was tested at three medical centers in the United States. The vaccine is produced by Sanofi-Pasteur, a French company that is part of the European drug manufacturer Sanofi-Aventis.
Health officials have been working quickly to develop a vaccine against bird flu. They are concerned that the bird flu virus in Asia and Russia might change and combine with a human influenza virus to create a new virus. They say this new virus could spread quickly around the world.
VOICE TWO:
Millions of birds in Asia have died from the h-five-n-one virus or were killed to prevent its spread. The virus has infected more than one hundred people. More than fifty of them have died. The infected people live in Cambodia, Indonesia, Thailand and Vietnam.
American health officials said the existence of a vaccine alone would not prevent the possible worldwide spread of the disease. The officials said countries need to quickly organize ways to give vaccine injections when they are provided. They said this would take cooperation, money and more scientific work.
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VOICE ONE:
A new report says the world's oceans have fewer kinds of fish than they did fifty years ago. The report said some kinds, or species, of fish have decreased by as much as fifty percent. It blames too much fishing, destruction of areas where fish live and climate change for the decrease.
Two scientists from Dalhousie University in Nova Scotia, Canada, wrote the report. Three other scientists took part in the study. They are from the Leibniz Institute for Marine7 Science in Germany. The publication Science reported their findings.
VOICE TWO:
The scientists used information from Japanese long-line fisheries going back to the nineteen fifties. They compared the information with information gathered by scientific observers from Australia and the United States.
The study is the first worldwide mapping of species of large fish that eat other fish. The study found the total catch for tuna and billfish has increased as much as ten times during the past fifty years.
The scientists found that tuna and billfish are disappearing in many areas. They say the problem is especially bad in waters near northwest Australia. In addition, other fish are accidentally caught when large fish are caught. This has caused the number of species to fall.
VOICE ONE:
The report said changes in temperature can also affect the number of fish species. It found that the kinds of fish expanded when the weather conditions known as El Nino caused warmer surface waters in the Pacific Ocean. But the number of species decreased when temperatures dropped.
The study identified five important areas in the world that have many different kinds of fish. They include areas off the east coast of Florida and south of Hawaii in the United States.
Other areas are near Australia's Great Barrier Reef, near Sri Lanka and in the southern Pacific Ocean, mainly north of Easter Island. The scientists said it is important to protect these areas now.
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VOICE TWO:
Scientists in South Korea say they have successfully produced an exact genetic8 copy of a dog. The scientists said they used the same methods that produced a sheep named Dolly nine years ago. A number of other animals have been copied, or cloned. They include cows, pigs, rabbits, mice and even a cat.
A team led by Woo-Suk Hwang of Seoul National University created an Afghan hound called Snuppy. Snuppy is a genetic copy of an adult dog. Last year, the team cloned human embryos9 and produced stem cells. Snuppy is now more than three months old. The announcement of his birth was reported this month in the publication Nature.
VOICE ONE:
About fifteen people needed thirty months to complete the experiment. Earlier attempts to clone a dog failed because of the difficulty of collecting dog eggs that are fully3 developed, or mature. The South Korean team found a way to harvest mature dog eggs in a laboratory. The team used a special liquid to force the egg down a tube, or oviduct, from the female reproductive organs.
Next, members of the team removed the nucleus11 of the egg. Then the nucleus was replaced with the nucleus of the animal to be cloned. Those cells were taken from the ear of the adult Afghan hound.
One thousand ninety five cloned embryos resulted. The embryos were placed into one hundred twenty three female dogs. Only three of them became pregnant. One lost the puppy before it was born. The team used a medical operation called a Cesarean Section to remove the two other puppies. One became sick and died after only twenty-two days. The surviving animal, Snuppy, was taken from a yellow Labrador retriever. The dog raised the puppy as if she were his natural mother.
VOICE TWO:
Snuppy looks exactly like the dog that provided his genetic material. Professor Hwang says it is too early to know if the puppy will have a personality like the older dog. He said the experiment should help demonstrate how genes12 and environment affect creation of different kinds of dogs.
Professor Hwang also said the study is a step toward creating dogs that could be given human sicknesses and then studied. He said his team's experiment is not meant to produce dogs for owners whose animals have died.
In March, the United Nations declared a ban on all kinds of cloning. But governments in many nations have disobeyed the ban.
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VOICE ONE:
Finally, we told you about a giant panda born last month at the National Zoo in Washington, D.C. Today we have more news of that baby panda. It's a boy! Animal experts who have examined him said he is in good health and getting bigger.
We also have panda news from the San Diego Zoo in the American state of California. A giant panda was born there on August second. Its mother, Bai Yun, had her baby after three hours of labor10.
VOICE TWO:
The arrival of the baby brought the giant panda population in the San Diego Zoo to four. The zoo has more of these animals than any other area except their native China.
The sex of the panda born in San Diego was not immediately known. Animal experts who gathered to watch television pictures of the birth said they could not see the baby. But they could hear it make loud noises. The baby is reported to have made happy sounds when its mother began to feed it.
(MUSIC)
VOICE ONE:
This SCIENCE IN THE NEWS program was written by Shelley Gollust and Jerilyn Watson. Our producer was Cynthia Kirk. I'm Barbara Klein.
VOICE:
And I'm Bob Doughty. Join us again next week at this time for more news about science in Special English on the Voice of America.
收听单词发音 |
1
doughty
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| adj.勇猛的，坚强的 | |
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2
vaccine
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| n.牛痘苗，疫苗；adj.牛痘的，疫苗的 | |
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fully
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| adv.完全地，全部地，彻底地；充分地 | |
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influenza
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| n.流行性感冒，流感 | |
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allergy
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| n.(因食物、药物等而引起的)过敏症 | |
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noted
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| adj.著名的，知名的 | |
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marine
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| adj.海的；海生的；航海的；海事的；n.水兵 | |
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genetic
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| adj.遗传的，遗传学的 | |
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embryos
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| n.晶胚；胚，胚胎( embryo的名词复数 ) | |
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labor
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| n.劳动，努力，工作，劳工；分娩；vi.劳动，努力，苦干；vt.详细分析；麻烦 | |
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nucleus
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| n.核，核心，原子核 | |
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genes
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| n.基因( gene的名词复数 ) | |
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