VOA英语2010年-Malaria: New Partnership Aims to Stop Parasi

A new partnership¹ is being launched to develop a malaria² vaccine³ that would prevent parasites⁵ from entering the liver. Most of the symptoms of the disease develop after parasites have had time to replicate⁶ there.

A new partnership is being launched to develop a malaria vaccine that would prevent parasites from entering the liver. Most of the symptoms of the disease develop after parasites have had time to replicate there.

The World Health Organization estimates that in 2008, there were 247 million cases of malaria worldwide, with one million deaths. It says in Africa, a child dies every 45 seconds from the disease.

The best treatment now available is artemisinin-based combination therapy. But an effective vaccine would be much better. That's the goal of the partnership involving the international, non-profit organization PATH, Merck Pharmaceuticals⁷ and New York University.

Finding a weakness

Scientists think they've discovered the Achilles heel of the malaria parasite⁴. After a bite by an infected mosquito, the parasite travels through the bloodstream and arrives at the liver. That's where scientists believe the best line of defense⁸ can be made.

Dr. Ashley Birkett is PATH's Malaria Vaccine Initiative director of pre and early clinical development.

"The parasite has a natural affinity⁹ for liver cells. Liver cells are the cells that the parasite can actually make copies of itself in once it enters the human body. So, it's goal once it enters the human bloodstream after an infectious bite is to find liver cells. And then it enters those liver cells through a set of specific interactions that we don't fully¹⁰ understand. But there is a critical event in that entry process that we think we can target through a vaccine approach," he says.

He says if the parasite cannot enter the liver, it cannot replicate and cause disease. But targeting a parasite is more difficult than targeting viruses or bacteria.

"This is a parasite," he says, "It's a very complex organism that has over 5,000 different gene¹¹ products that it makes. It's a lot more complicated than a typical virus. I think also there have been limited resources that have been applied¹² to malaria vaccine development over the years. But we are having significant success now. And through a partnership with GlaxoSmithKline, PATH MVI is engaged in a very large phase-three clinical study, which is a last stage of clinical testing before a vaccine can actually be licensed¹³ and start saving lives."

Birkett says the vaccine has been evaluated in 16,000 young children in seven sub-Saharan African countries. It has an efficacy rate of 50 percent.

"So, given that we're looking in the order of 900,000 deaths from malaria in young children primarily per year in sub-Saharan Africa, a vaccine with 50 percent efficacy is actually a very significant achievement. But we want to do better," says Birkett.

The vaccine being tested depends on the body producing very large numbers of antibodies against the malaria parasite. That's makes it more difficult to have a higher efficacy rate. The hope of a new vaccine is to specifically target a different area of the parasite with fewer anti-bodies.

Malaria taking a toll¹⁴

Dr. Birkett says this would relieve African countries of some heavy burdens.

"We're looking at countries in sub-Saharan Africa, which already have significant burdens to deal with in terms of economic impact of these global infectious diseases. And malaria has a huge economic impact. So a vaccine that can be highly protective and prevent these clinical diseases and up to 900,000 deaths per year is going to have a significant health and economic benefit in these countries," he says.

Dr. Birkett says the cost of such a vaccine would be kept as low as possible. Clinical testing on the proposed vaccine is still three or four years away. Malaria immunization would be included as part of a child's routine vaccinations¹⁵.

1 partnership   

n.合作关系，伙伴关系

参考例句：

• The company has gone into partnership with Swiss Bank Corporation.这家公司已经和瑞士银行公司建立合作关系。
• Martin has taken him into general partnership in his company.马丁已让他成为公司的普通合伙人。

2 malaria   

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。

3 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。

4 parasite   

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。

5 parasites   

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。

6 replicate   

v.折叠，复制，模写；n.同样的样品；adj.转折的

参考例句：

• The DNA of chromatin must replicate before cell division.染色质DNA在细胞分裂之前必须复制。
• It is also easy to replicate,as the next subsection explains.就像下一个小节详细说明的那样，它还可以被轻易的复制。

7 pharmaceuticals   

n.医药品；药物( pharmaceutical的名词复数 )

参考例句：

• the development of new pharmaceuticals 新药的开发
• The companies are pouring trillions of yen into biotechnology research,especially for pharmaceuticals and new seeds. 这些公司将大量资金投入生物工艺学研究，尤其是药品和新种子方面。 来自《简明英汉词典》

8 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。

9 affinity   

n.亲和力，密切关系

参考例句：

• I felt a great affinity with the people of the Highlands.我被苏格兰高地人民深深地吸引。
• It's important that you share an affinity with your husband.和丈夫有共同的爱好是十分重要的。

10 fully   

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。

11 gene   

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。

12 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

13 licensed   

adj.得到许可的v.许可，颁发执照(license的过去式和过去分词)

参考例句：

• The new drug has not yet been licensed in the US. 这种新药尚未在美国获得许可。
• Is that gun licensed? 那支枪有持枪执照吗？

14 toll   

n.过路(桥)费；损失，伤亡人数；v.敲(钟)

参考例句：

• The hailstone took a heavy toll of the crops in our village last night.昨晚那场冰雹损坏了我们村的庄稼。
• The war took a heavy toll of human life.这次战争夺去了许多人的生命。

15 vaccinations   

n.种痘，接种( vaccination的名词复数 )；牛痘疤

参考例句：

• Vaccinations ensure one against diseases. 接种疫苗可以预防疾病。 来自《简明英汉词典》
• I read some publicity about vaccinations while waiting my turn at the doctor's. 在医生那儿候诊时，我读了一些关于接种疫苗的宣传。 来自《简明英汉词典》