VOA慢速英语2019 科学家发现携带病毒蚊子的"克星"（在线收听）

Scientists Find a New Way To Kill Disease-Carrying Mosquitoes

Scientists say they have killed nearly all the disease-carrying mosquitoes on two islands in China using a new method.

科学家表示，他们用一种新方法杀死了中国两座岛屿上几乎所有携带疾病的蚊子。

That is the good news.

这是个好消息。

The bad news is that the method may cost a lot of money and not work as well in larger areas.

坏消息是，这种方法可能费用高昂，而且在更大的范围内效果并不理想。

In the experiment, researchers targeted Asian tiger mosquitoes. The insects have white stripes and can spread dengue fever, Zika and other diseases.

在实验中，研究人员以亚洲虎蚊为目标。这种昆虫有白色条纹，会传播登革热、寨卡病毒和其他疾病。

To limit the insects’ ability to reproduce, scientists first infected a group of mosquitoes with a kind of virus-fighting bacteria. Then they hit them with a small amount of radiation.

为了限制蚊子的繁殖能力，科学家们首先让一群蚊子感染了一种抗病毒细菌。接着，科学家用少量的辐射攻击它们。

The affected mosquitoes were then released onto two small islands near Guangzhou, China. The area suffers from dengue fever.

受影响的蚊子随后被释放到中国广州附近的两座小岛上。该地区有登革热。

The scientists reported that, following the insects’ release, the number of female mosquitoes responsible for spreading dengue fever dropped by 83 to 94 percent each year.

科学家们报告称，蚊子被释放到岛上后，传播登革热的雌性蚊子数量每年下降83%到94%。

That drop is similar to what happens after spraying insecticide or using mosquitoes whose genes have been changed.

这种下降趋势与喷洒杀虫剂或投放基因已经改变的蚊子的成果类似。

At times, the new method worked even better than that. Some weeks, researchers saw no signs of disease-carrying mosquitoes.

有时，新方法的效果甚至更好。数周后，研究人员没有发现携带疾病的蚊子的迹象。

Zhiyong Xi is with Michigan State University. He led the research team. Xi said that no other mosquito control method has had that kind of total success.

习志勇就职于密歇根州立大学。他领导了这一研究小组。习志勇表示，其他的蚊子控制法尚未取得如此彻底的成功。

But to achieve that success, researchers had to introduce lots of new mosquitoes onto the islands – up to 4 million each week, over 18 weeks.

但为了取得成功，研究人员不得不在岛上引进大量的新蚊子——每周多达400万只，持续时间为18周。

Scott O’Neill of the World Mosquito Program says the number of insects needed to control mosquitoes this way is likely too large for most areas.

世界蚊子计划的负责人斯科特·奥尼尔表示，用这一方法控蚊所需的蚊子数量对大多数地区来说可能太多了。

Biologist Brian Lovett also had concerns. He is with the University of Maryland, just outside Washington, D.C. Lovett said, “You have to keep doing it.”

生物学家布莱恩·洛维特（Brian Lovett）也对此表示担忧。他就职于华盛顿特区外的马里兰大学。洛维特说：“你必须得不间断地进行。”

If the process is not repeated, new mosquitoes come in or grow up to replace those that died. Repeating the process could be very costly, Lovett noted.

如果不重复（引进蚊子）过程，新的蚊子就会入侵或繁殖，取代那些死亡的蚊子。洛维特指出，而重复这一过程可能代价高昂。

Researchers from the experiment say the cost will go down as the technology improves. They estimate the cost will soon be about the same as pest sterilization methods, and less costly than some insecticides.

进行该实验的研究人员表示，随着技术的改进，成本将会下降。他们预计，成本很快就会和害虫消毒方法持平，而且比一些杀虫剂更便宜。

The team is working on a mosquito-control project in an area about four times larger than the islands they used two years ago. Their findings from that first experiment appeared this month in the journal Nature.

该小组正在一座比两年前实验的岛屿大四倍的地区进行蚊子控制项目。他们的第一个实验结果发表在本月的《自然》杂志上。

I’m Kelly Jean Kelly.

Words in This Story

insecticide - n. a chemical substance that is used to kill insects

pest - n. an animal or insect that causes problems for people especially by damaging crops

sterilization - n. way to make something unable to produce young