媒体英语会带大家一起学习 BBC 撰稿人在报道世界大事时常用到的单词和短语。

科学家可能已找到对付臭虫（又称床虱）的办法。这类昆虫非常难控制，不过近期的科研结果有希望帮助科学家们研制出一系列新的、更有效的控制这一害虫的方法。请听来自 BBC Rebecca Morelle 的报道：

They feast on our blood while we sleep - leaving itchy, red welts as their calling card. Bedbugs are an insect that many would like to see the back of. But in North America, Europe and Australia, infestations are on the rise - and our insecticides are losing their bite.

Researchers at the University of Kentucky in the US have found 14 genes associated with resistance to these chemicals. They're causing a number of biological changes in the bedbugs. These include the development of a thicker skin that stops the poisons from penetrating and mutations within the insects' bodies that prevent the toxins from hitting the nervous system.

The genes linked to these changes are active in the insect's tough outer shell - creating a formidable first line of defence. These findings could help scientists to develop new insecticides that could either turn these genes off or bypass the pest's molecular shields.

But until these substances are developed, exterminators are having to resort to more primitive tactics.