VOA标准英语2010年-Grounded Mosquitoes Could Halt Spread

The dengue virus is spread through the bite of an infected female Aedes egypti mosquito. The disease causes flu-like symptoms, including high fever, muscle aches and sometimes death. Each year, the disease strikes between 50 and 100 million people living in tropical and subtropical regions.

There are no effective treatments for dengue, so public health experts focus on prevention to keep the disease under control.

That's what researchers at the University of California Irvine and the British biotech company, Oxitec, have done by creating a new breed of mosquito. "We put a gene¹ in, that in the next generation, females won't be able to fly," explains UC-Irvine biologist Anthony James. "So when a wild type female mates with a [genetically altered] male, all of her daughters are incapable² of flying."

Since the female mosquito is the one that spreads the disease, creating female mosquitoes that can't fly is key to controlling dengue. "It's only the females that feed on blood and transmit disease, so the males are not part of the transmission dynamics," James says. "So if you can reduce the number of females, ultimately the population crashes and you don't have dengue transmission anymore."

A safer alternative

James says using this new breed of mosquito could be a more benign³ and, perhaps, more effective alternative to spraying insecticides, a commonly-used strategy to control dengue. "Insecticides require people to be able to find where the mosquitoes are. It requires care in their use because insecticides have off-target effects." And, he adds, they are more costly⁴ since they require more personnel and materials.

This "no-fly" strategy is still in the testing stage. James and his colleagues are now planning what they call cage tests, where the genetically-modified mosquitoes are placed in huge outdoor cages and their effectiveness in stopping transmission of dengue is assessed.

Within a year, James hopes he can begin testing the strategy in places where dengue is prevalent.

The research is published in the "Proceedings⁵ of the National Academy of Sciences."

 

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 incapable   

adj.无能力的，不能做某事的

参考例句：

• He would be incapable of committing such a cruel deed.他不会做出这么残忍的事。
• Computers are incapable of creative thought.计算机不会创造性地思维。

3 benign   

adj.善良的，慈祥的；良性的，无危险的

参考例句：

• The benign weather brought North America a bumper crop.温和的气候给北美带来大丰收。
• Martha is a benign old lady.玛莎是个仁慈的老妇人。

4 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。

5 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