VOA慢速英语20060718b

SCIENCE IN THE NEWS - Hepatitis: Five Diseases That All Have the Same Target -- the LiverBy Mario Ritter and Nancy Steinbach

Broadcast: Tuesday, July 18, 2006

VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty¹.

VOICE TWO:


A nurse with two patients at a hospital in eastern Ukraine in 2003 after an outbreak of hepatitis A

And I'm Barbara Klein. This week -- all about five diseases caused by five different viruses. These diseases all attack the liver. Doctors have one name for them: hepatitis.

(MUSIC)

VOICE ONE:

The liver is in the upper right part of the stomach area. This dark red organ is big -- it weighs more than one kilogram. And it has a big job. The liver helps to clean the blood and fight infection. It also helps break down food and store energy until the body needs it.

Hepatitis destroys liver cells. But some kinds of hepatitis are much more serious than others.

The five kinds that scientists have identified over the years are called by the letters A through E. Which kind a person has can only be identified by tests for antibodies in the blood.

Antibodies are special proteins that the defense² system produces in reaction to a threat. Identify the antibody and you identify the threat.

VOICE TWO:

Hepatitis A is usually spread through human waste in water or food. It is in the same group of viruses as those that cause polio.

The hepatitis A virus causes high body temperature, tiredness and pain. It causes problems with the stomach and intestines³, making it difficult to eat or digest food. Also, the skin of a person with hepatitis may become yellow. This is a sign that the liver is not operating normally.

To help prevent the spread of hepatitis A, people should wash their hands after they use the bathroom or change a baby's diaper. People should also wash their hands before they eat or prepare food.

VOICE ONE:

Hepatitis A can spread quickly to hundreds or thousands of people. But this virus is deadly in less than one percent of cases. In fact, many people never even get sick. Those who do generally recover within two months.

The Centers for Disease Control Web site -- cdc.gov -- says the usual treatment is bed rest and a balanced diet. Also, a person should avoid alcohol for at least six months.

People who have had hepatitis A cannot get it again. And there is a vaccine⁴ that can prevent hepatitis A.

(MUSIC)

VOICE TWO:


A 6-month-old Vietnamese girl gets her third and final injection of hepatitis B vaccine in Hanoi

The World Health Organization calls Hepatitis B one of the major diseases of mankind. It says two thousand million people, or one-third of all people, are infected with the hepatitis B virus. The highest rates are in developing countries.

This virus is in the same group as the herpes and smallpox⁵ viruses. There have been hepatitis B vaccines⁶ since the early nineteen eighties.

Hepatitis B spreads when blood from an infected person enters the body of another person.

An infected mother can infect her baby. The virus can also spread through sex, and if people share injection devices. Blood products from an infected person can spread hepatitis B. And people can get infected if they share personal-care items that might have blood on them, like shaving razors or toothbrushes.

VOICE ONE:

Worldwide, most hepatitis B infections happen in children. Young children are the ones most likely to develop a lifelong infection. The W.H.O. estimates that more than three hundred fifty million people are chronically⁸ infected with the virus.

The risk of a lifelong infection is small for those infected after age four. But about ninety percent of those infected with hepatitis B during their first year develop chronic⁷ infections.

They are at high risk of death from liver disease and liver cancer. When scientists developed a hepatitis B vaccine, it was considered the first medicine to protect people against cancer.

(MUSIC)

VOICE TWO:

Hepatitis C is even more dangerous. Like hepatitis B, it spreads when blood from an infected person enters someone who is not infected. It belongs to the same group of viruses as yellow fever and West Nile virus.

Most people infected with hepatitis C develop chronic infections, often without any signs. They are at high risk for liver disease and liver cancer.

The World Health Organization says about one hundred eighty million people are infected with hepatitis C. And each year as many as four million more become infected. The W.H.O. says the highest rates are in Africa, Latin America and Asia.

VOICE ONE:

Scientists have been working to develop a vaccine against hepatitis C. The virus was first observed in nineteen seventy-four. But it was not officially recognized as a new kind of hepatitis until nineteen eighty-nine.

Research suggests that each year as many as twelve thousand people in the United States die of hepatitis C. A study by the National Institutes of Health found high rates of the virus in some groups, including prisoners and homeless people.

People who received blood and blood products before nineteen ninety-two also have an increased risk.

(MUSIC)

VOICE TWO:

Hepatitis D is also spread through blood but only infects people who already have hepatitis B. The virus greatly increases the chance of severe liver damage. The W.H.O says ten million people around the world are infected with hepatitis D.

Doctors can treat some cases of hepatitis B, C and D. The drugs used are very costly⁹, however. But they are less costly than another treatment possibility: getting a new liver.

VOICE ONE:

The fifth virus is hepatitis E. Experts say it spreads the same way as hepatitis A -- through infectious¹⁰ waste. Outbreaks often result from polluted supplies of drinking water. Medical science recognized hepatitis E as a separate disease in nineteen eighty.

Hepatitis E is also found in animal waste. Studies have shown that the virus can infect many kinds of animals, including pigs, cows and monkeys.

The W.H.O. says epidemics¹¹ of hepatitis E have been reported in Central and Southeast Asia, North and West Africa and Mexico.

There are no vaccines or medicines for hepatitis E. Most people recover, usually in several weeks or months. But the disease can cause liver damage. And, in some cases, hepatitis E is deadly.

The virus is especially dangerous to pregnant¹² women. Twenty percent of women with hepatitis E in the last three months of pregnancy¹³ die.

(MUSIC)

VOICE TWO:

There are no cures for any kind of hepatitis. The only way to protect against infection is to avoid contact with the virus. And that may be difficult or impossible.

But experts say vaccines can greatly reduce the risk of hepatitis A and B. And there are other steps people can take to protect themselves. As we said, a person can get some kinds of hepatitis through sex or sharing needles.

VOICE ONE:

Supplies of blood products should be carefully tested for hepatitis. People in high-risk groups and those who have had hepatitis should not give blood. Exceptions may be made for people who had hepatitis A before age eleven.

Donated organs can also spread hepatitis.

Experts say the only way to control the spread of hepatitis is through preventive measures. Even something as simple as washing your hands.

(MUSIC)

VOICE TWO:

SCIENCE IN THE NEWS was written by Mario Ritter and Nancy Steinbach. Brianna Blake was our producer. If you have a question about science, send it by e-mail to [email protected]. Please understand that we cannot answer questions personally, but we might be able to answer your question on our show. I'm Barbara Klein.

VOICE ONE:

And I'm Bob Doughty. You can learn more about hepatitis, and download transcripts¹⁴ and audio of our programs, at www.unsv.com. Listen again next week for more news about science in Special English on the Voice of America.

1 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

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 intestines   

n.肠( intestine的名词复数 )

参考例句：

• Perhaps the most serious problems occur in the stomach and intestines. 最严重的问题或许出现在胃和肠里。 来自辞典例句
• The traps of carnivorous plants function a little like the stomachs and small intestines of animals. 食肉植物的捕蝇器起着动物的胃和小肠的作用。 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 smallpox   

n.天花

参考例句：

• In 1742 he suffered a fatal attack of smallpox.1742年，他染上了致命的天花。
• Were you vaccinated against smallpox as a child?你小时候打过天花疫苗吗？

6 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。

7 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

8 chronically   

ad.长期地

参考例句：

• Similarly, any pigment nevus that is chronically irritated should be excised. 同样，凡是经常受慢性刺激的各种色素痣切勿予以切除。
• People chronically exposed to chlorine develop some degree of tolerance. 人长期接触氯气可以产生某种程度的耐受性。

9 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

10 infectious   

adj.传染的，有传染性的，有感染力的

参考例句：

• 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！

11 epidemics   

n．流行病

参考例句：

• Reliance upon natural epidemics may be both time-consuming and misleading. 依靠天然的流行既浪费时间，又会引入歧途。
• The antibiotic epidemics usually start stop when the summer rainy season begins. 传染病通常会在夏天的雨季停止传播。

12 pregnant   

adj.怀孕的，怀胎的

参考例句：

• She is a pregnant woman.她是一名孕妇。
• She is pregnant with her first child.她怀了第一胎。

13 pregnancy   

n.怀孕，怀孕期

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
• Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。

14 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