At least 10 percent of young adults, and perhaps 30 percent of teenagers, carry the deadly meningococcal bacterium, 至少有10%的年轻人和也许30%的少年携带着致命的脑膜炎球菌，

but it lives quite harmlessly in the throat. 但脑膜炎球菌完全无害地生活在咽喉里。

Just occasionally—in about one young person in a hundred thousand—it gets into the bloodstream and makes them very ill indeed. 在非常偶然的情况下——大约10万个年轻人中间的1个——脑膜炎球菌会进入血液，害得他们生大病。

In the worst cases, death can come in twelve hours. That's shockingly quick. 在最严重的情况下，人可以在12个小时内死亡。速度是极快的。

"You can have a person who's in perfect health at breakfast and dead by evening," says Marsh. “一个人吃早饭时还是好好的，到晚上就死了。”马什说。

We would have much more success with bacteria if we weren't so profligate with our best weapon against them: antibiotics. 要是我们不是那样滥用对付细菌的最佳武器：抗生素，我们本来会取得更大的胜利。

Remarkably, by one estimate some 70 percent of the antibiotics used in the developed world are given to farm animals, often routinely in stock feed, 值得注意的是，据一项估计，在发达世界使用的抗生素当中，有大约70%往往经常用于饲料中，

simply to promote growth or as a precaution against infection. 只是为了促进生长或作为对付感染的预防措施。

Such applications give bacteria every opportunity to evolve a resistance to them. 因此，细菌就有了一切机会来产生抗药性。

It is an opportunity that they have enthusiastically seized. 它们劲头十足地抓住这样的机会。

In 1952, penicillin was fully effective against all strains of staphylococcus bacteria, 1952年，青霉素用来对付各种葡萄球菌完全有效，

to such an extent that by the early 1960s the U.S. surgeon general, William Stewart, felt confident enough to declare: 以致美国卫生局局长威廉·斯图尔特在20世纪60年代初敢说：

"The time has come to close the book on infectious diseases. “现在是该结束传染病时代的时候了。

We have basically wiped out infection in the United States." 我们美国已经基本上消灭了传染病。”

Even as he spoke, however, some 90 percent of those strains were in the process of developing immunity to penicillin. 然而，即使在他说这番话的时候，大约有90%的这类病菌已经对青霉素产生抗药性。