2007年VOA标准英语-Genetically Altered Mosquitoes May Offer Hope t

By Jessica Berman
Washington
19 March 2007

Transgenic mosquito

Scientists say they are a step closer to showing that it may be possible to genetically² alter mosquitoes to control malaria³, a disease that kills more than a million people in developing countries every year. VOA's Jessica Berman reports.

The spread of malaria is like a two-way street.

The disease is spread to humans through the bite of mosquitoes infected with malaria parasites⁵, the most dangerous of these being plasmodium falciparum. Uninfected mosquitoes become infected with the parasite⁴ by biting infected animals.

In sub-Saharan Africa and parts of Asia an estimated 300 million people are infected every year, more than one million of them are children, many of whom die.

Years of attempting to cure the disease with antibiotics⁶ and quinine drugs have caused the parasite to become resistant⁷ to treatment.

Scientists are trying to come up with novel strategies for conquering malaria. One idea that has been around for a number of years is the creation of genetically altered mosquitoes that could be released into the environment.

The so-called transgenic insects would be resistant to infection by falciparum. Through breeding, the altered insects would gradually replace the population of mosquitoes capable of becoming infected with the parasite

Marcelo Jacobs-Lorena of the Malaria Research Institute at Johns Hopkins University in Baltimore, Maryland, says investigators⁸ created genetically engineered mosquitoes that were more hardy⁹ than so-called wild-type mosquitoes that carry the parasite, and put the blood sucking insects to the test.

"What we have shown in this work that will be published is that the mosquito that carries the gene¹ has an advantage if it bites an infected individual," he said.

In an article published in the journal Proceedings¹⁰ of the National Academy of Sciences, Jacobs-Lorena and colleagues report having an equal number of genetically engineered mosquitoes and wild-type insects feast on a malaria-infected mouse. After nine generations, the percent of altered mosquitoes increased from 50 percent to 70 percent.

If and when scientists are able to breed transgenic mosquitoes in numbers that might make a difference in the spread of malaria, Jacobs-Lorena says researchers have to make sure such insects do not cause an unforeseen harm.

"We have to be absolutely sure that any genetically modified mosquito does not cause any harm in the environment or cause unpredictable harm to people that they bite," he said. "But I think we are on the way."

Despite the obstacles, Jacobs-Lorena is optimistic that genetically altered mosquitoes will one day take their place alongside other strategies to fight malaria.

1 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。

2 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

3 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。

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 antibiotics   

n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )

参考例句：

• the discovery of antibiotics in the 20th century 20世纪抗生素的发现
• The doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

7 resistant   

adj.(to)抵抗的，有抵抗力的

参考例句：

• Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
• They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。

8 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

9 hardy   

adj.勇敢的，果断的，吃苦的；耐寒的

参考例句：

• The kind of plant is a hardy annual.这种植物是耐寒的一年生植物。
• He is a hardy person.他是一个能吃苦耐劳的人。

10 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼