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VOA慢速英语2014--Increase Seen in Common Form of Malaria 增加对常见疟疾的认识

时间:2014-02-01 14:39:00

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Increase Seen in Common Form of Malaria1 增加对常见疟疾的认识

From VOA Learning English, this is Science in the News.  I’m Mario Ritter.

And I’m Christopher Cruise.  Today we tell about a warning from tropical disease experts.  They are seeing an increase in infections from one kind of malaria parasite2.  We also tell about plans for human testing of a gene3 therapy for heart disease.  Then we report on efforts in Liberia to control sales of medicines.  And we tell how Australian scientists are working to help save koalas from disease. 

Between 300 million and 500 million cases of malaria are reported worldwide each year.  Plasmodium falciparum, a deadly parasite, is responsible for most of the cases.  But experts say a lesser4 known form of the disease could become a more serious threat.  They are seeing an increase in infections from the vivax malaria parasite. 

An estimated 2.5 billion people live in areas where Plasmodium vivax is common.  It is one of five kinds of malaria carried by mosquitoes.  The vivax parasite infected 20 million people in 2010.  Its signs are less severe than the more common falciparum malaria, which kills about 660,000 people each year.

Peter Zimmerman is a malaria expert with Case-Western Reserve University in Ohio.  He says people who become infected with vivax usually feel like they are suffering from a really bad case of influenza5.

“It’s highly associated with pretty severe anemia6 and all the sort, you know, of ‘I don’t feel good’ symptoms that, that go along with it: headache, nausea7, being tired, you know, having no energy.”

Yet, he says, malaria can be deadly in someone who is half-starved or suffering from more than one infection.  The organism can also hide in the liver and return many times, causing the disease to reappear.

Until now, experts believed 95 percent of the at-risk population in some areas was protected from vivax infection.  This is because they lack a certain kind of protein in their red blood cells called a “Duffy” protein.  Without it, vivax parasites8 cannot enter the blood cells. 

But Peter Zimmerman and other researchers have found that in Madagascar, people without the Duffy protein may be carrying the vivax parasite.

“What we are seeing in Madagascar is, in communities where you have high percentages of Duffy-positive people and high percentages of Duffy-negative people, it looks like the Duffy-negatives become equally susceptible9 to Vivax.”

He says it appears the parasite may be changing so it can overcome natural resistance and infect blood cells that lack the Duffy protein.  If so, that could mean that vivax is becoming a bigger threat.  But he notes research shows that Duffy negative people are still at a lower risk for vivax malaria.  Peter Zimmerman presented his results at a meeting of the American Society of Tropical Medicine and Hygiene10 in Washington.

Two reports on changes in the infectiousness of Plasmodium vivax were published in the journal PLoS Neglected Tropical Diseases

 

New Discovery May Help Fight Heart Disease

Researchers are ready to begin human testing of a new gene therapy to treat a major cause of heart disease.  The therapy shrinks enlarged hearts.  It helps to improve blood flow and the way the heart operates. 

Heart failure is a leading cause of sickness and death around the world.  The heart becomes weaker and gets bigger as it works harder to pump enough blood to the rest of the body.  A heart attack, untreated high blood pressure or blocked arteries11 can lead to heart failure.  Once the condition develops, the victim usually dies within five years. 

People who suffer heart failure lack a fully12 operational gene called SUMO-1.  It helps control calcium13 that goes in and out of cells in the ventricles, which pump blood to the body. 

Roger Hajjar is a cardiologist with Mount Sinai School of Medicine in New York.  He led experiments on pigs with heart failure.  He found that just a single injection of the gene SUMO-1 improved the operation of the animals’ hearts. 

“Regardless of the cause that induced the heart to, to be big, we were able to reverse that.”

His research team discovered another gene, called SERCA2.  This gene also controls the movement of calcium in heart cells.  Their human tests of replacement14 gene therapy with SERCA2 are showing similar results to the SUMO-1 experiments in animals. 

Doctor Hajjar believes that injecting both genes15 at the same time into cardiac failure patients might help even more. 

“Since we’ve had the experience with SERCA2, we know pretty much the path towards clinical trials from, from discovery to, to the bedside.  And, we feel that within a couple of years, we should be able to take this, this program forward, for, in terms of gene therapy in patients.”

The treatment involving SUMO-1 and SERCA2 uses a harmless cold virus to carry the genes into the heart.

Liberian Officials Concerned by Fake Medicines 

Liberia is taking steps against the sellers of fake -- copied -- or out-of-date medicines.  But the government efforts have met resistance from some Liberians, especially in rural communities.  They say they only have enough money to pay for old or fake medicines.  The traffic and sale of such drugs is widespread in West Africa.  But this industry has created serious risks to public health.

It is not hard to find traveling drug salesmen in Liberia.  They are known locally as “black bag doctors.”  

John Harris was walking along a road just a few kilometers outside the capital, Monrovia.  That is where a VOA reporter met him.

John Harris wore a backpack and carried a bucket.  Both were full of unmarked plastic bags of pills.  He said they were painkillers16 and anti-malaria drugs. 

John Harris said this is not the kind of life he expected when he finished medical school.

“How does the government expect us to survive when there is no job?  So I do this, moving from villages and towns, and sell these drugs to the people.  At least we are helping17 government.  Some of the places we go, there are no health facilities.  So I think we are a help.” 

But it is a crime to sell medicines in the streets without official permission.  Inspectors18 from Liberia's Pharmaceutical19 Board have been searching for drug salesmen like John Harris.

Chief Pharmacist Reverend Tijli Tarty Tyee says the medicines and treatments from black bag sellers are not effective.  He says they are either old, damaged by sun or moisture, or just fake.  He says such medicines cannot cure sicknesses.

“… people taking the medicines, there is a potential of having what we call microbial resistance to the medicines.  And when we have resistance to our important medication, then we are in a very serious, serious situation.”

Tijli Tarty Tyee says he understands that people need medicines -- and the costs have to be kept low.  “They want to have a shortcut20 in getting medicines, but that shortcut is dangerous to them,” he says.

In addition to the resistance of local communities, the sellers themselves have also resisted.  The Liberian official says inspectors have been injured on the job. 

The United Nations’ Office on Drugs and Crime says fake medicines in West Africa are both imported and manufactured locally.  And government supervision21 of the medicines is limited. 

Flour has been identified as the antibiotic22 amoxicillin.  Manufacturers try to increase profits by reducing the amount of an active ingredient.  Or real medicines can make their way into a street seller’s backpack after they are too old to help cure disease or control pain. 

Experts say the true depth of the problem is nearly impossible to measure in West Africa.  The UN’s Office on Drugs and Crime says even doctors and pharmacists cannot be totally sure what they are administering to patients is real. 

Finally, Australian scientists are climbing trees to study healthy koalas in a colony.  Researchers at the University of Queensland are going to great heights to document the lives and behaviors of the animals.  The goal is to help save other koalas threatened by disease.

A koala is sometimes called a “bear” because it looks similar to that animal.  But the koala is different, and native to Australia.

Although the animals are called “bears,” they are really marsupials, related to kangaroos and opossums.  They survive by eating leaves from eucalyptus23 trees. 

The researchers say koalas in parts of the country are suffering from chlamydia.  The disease causes blindness and inability for the females to reproduce.  Experts believe genetics could be partly to blame for the sickness. 

Healthy animals in northeastern Australia are captured and tested to help the research team learn why they do NOT have the disease.  Researchers are especially interested in joeys, the baby koalas.  After the female koala gives birth, she carries her joey in her pouch24 for six months. 

In addition to chlamydia, other threats to koalas include water pollution, loss of homeland and road accidents.

The study of koalas will continue for years across 63,000 hectares in Australia. 

This Science in the News written by Milagros Ardin and Jerilyn Watson.  Our producer was June Simms.  I’m Christopher Cruise.


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点击收听单词发音收听单词发音  

1 malaria B2xyb     
n.疟疾
参考例句:
  • He had frequent attacks of malaria.他常患疟疾。
  • Malaria is a kind of serious malady.疟疾是一种严重的疾病。
2 parasite U4lzN     
n.寄生虫;寄生菌;食客
参考例句:
  • The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
  • I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫,我要自己养活自己。
3 gene WgKxx     
n.遗传因子,基因
参考例句:
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
4 lesser UpxzJL     
adj.次要的,较小的;adv.较小地,较少地
参考例句:
  • Kept some of the lesser players out.不让那些次要的球员参加联赛。
  • She has also been affected,but to a lesser degree.她也受到波及,但程度较轻。
5 influenza J4NyD     
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。
6 anemia joGy3     
n.贫血,贫血症
参考例句:
  • The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。
  • I was put on iron tablets for my anemia.我曾因贫血吃补铁药片。
7 nausea C5Dzz     
n.作呕,恶心;极端的憎恶(或厌恶)
参考例句:
  • Early pregnancy is often accompanied by nausea.怀孕期常有恶心的现象。
  • He experienced nausea after eating octopus.吃了章鱼后他感到恶心。
8 parasites a8076647ef34cfbbf9d3cb418df78a08     
寄生物( parasite的名词复数 ); 靠他人为生的人; 诸虫
参考例句:
  • These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的,而与寄生虫无关。
  • Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。
9 susceptible 4rrw7     
adj.过敏的,敏感的;易动感情的,易受感动的
参考例句:
  • Children are more susceptible than adults.孩子比成人易受感动。
  • We are all susceptible to advertising.我们都易受广告的影响。
10 hygiene Kchzr     
n.健康法,卫生学 (a.hygienic)
参考例句:
  • Their course of study includes elementary hygiene and medical theory.他们的课程包括基础卫生学和医疗知识。
  • He's going to give us a lecture on public hygiene.他要给我们作关于公共卫生方面的报告。
11 arteries 821b60db0d5e4edc87fdf5fc263ba3f5     
n.动脉( artery的名词复数 );干线,要道
参考例句:
  • Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
  • This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》
12 fully Gfuzd     
adv.完全地,全部地,彻底地;充分地
参考例句:
  • The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气,然后全部呼出。
  • They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。
13 calcium sNdzY     
n.钙(化学符号Ca)
参考例句:
  • We need calcium to make bones.我们需要钙来壮骨。
  • Calcium is found most abundantly in milk.奶含钙最丰富。
14 replacement UVxxM     
n.取代,替换,交换;替代品,代用品
参考例句:
  • We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
  • They put all the students through the replacement examination.他们让所有的学生参加分班考试。
15 genes 01914f8eac35d7e14afa065217edd8c0     
n.基因( gene的名词复数 )
参考例句:
  • You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因,所以能够活得很长。 来自《简明英汉词典》
  • Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
16 painkillers 1a67b54ddb73ea8c08a4e55aa1847a55     
n.止痛药( painkiller的名词复数 )
参考例句:
  • The doctor gave him some painkillers to ease the pain. 医生给了他一些止疼片以减缓疼痛。 来自辞典例句
  • The primary painkillers - opiates, like OxyContin - are widely feared, misunderstood and underused. 人们对主要的镇痛药——如鸦片剂奥施康定——存在广泛的恐惧、误解,因此没有充分利用。 来自时文部分
17 helping 2rGzDc     
n.食物的一份&adj.帮助人的,辅助的
参考例句:
  • The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
  • By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。
18 inspectors e7f2779d4a90787cc7432cd5c8b51897     
n.检查员( inspector的名词复数 );(英国公共汽车或火车上的)查票员;(警察)巡官;检阅官
参考例句:
  • They got into the school in the guise of inspectors. 他们假装成视察员进了学校。 来自《简明英汉词典》
  • Inspectors checked that there was adequate ventilation. 检查员已检查过,通风良好。 来自《简明英汉词典》
19 pharmaceutical f30zR     
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。
20 shortcut Cyswg     
n.近路,捷径
参考例句:
  • He was always looking for a shortcut to fame and fortune.他总是在找成名发财的捷径。
  • If you take the shortcut,it will be two li closer.走抄道去要近2里路。
21 supervision hr6wv     
n.监督,管理
参考例句:
  • The work was done under my supervision.这项工作是在我的监督之下完成的。
  • The old man's will was executed under the personal supervision of the lawyer.老人的遗嘱是在律师的亲自监督下执行的。
22 antibiotic KNJzd     
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。
23 eucalyptus jnaxm     
n.桉树,桉属植物
参考例句:
  • Eucalyptus oil is good for easing muscular aches and pains.桉树油可以很好地缓解肌肉的疼痛。
  • The birds rustled in the eucalyptus trees.鸟在桉树弄出沙沙的响声。
24 pouch Oi1y1     
n.小袋,小包,囊状袋;vt.装...入袋中,用袋运输;vi.用袋送信件
参考例句:
  • He was going to make a tobacco pouch out of them. 他要用它们缝制一个烟草袋。
  • The old man is always carrying a tobacco pouch with him.这老汉总是随身带着烟袋。

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