The Ayatollah also used extremely virulent language against the United States and Britain, calling them Iran's top enemies.

VOA: standard.2009.12.07

In the Sabin vaccine, or the oral polio vaccine, now you have a non-virulent virus.

在沙宾疫苗,即口服小儿麻痹症疫苗中,存在非致病性病毒

耶鲁公开课 - 生物医学工程探索课程节选

A Christian civilization was deeply at the root of this cluster of ideas we call Manifest Destiny, as was a virulent kind of nationalism that boomed after the War of 1812 and through the 1820s into the 1830s.

基督教文明是我们所称的命运天定,及其相关思想的核心,它是一种有害的民族主义,在1812年战争后兴起,并流行于十九世纪二十年代和三十年代

耶鲁公开课 - 美国内战与重建课程节选

It says Iranian President Mahmoud Ahmadinejad continues a "virulent anti-Semitic campaign,"

VOA: standard.2009.10.26

So, it's more effective because it's a live virus but it's a little bit more concerning because it's a live virus as well, in that you trust that it's attenuated but could it convert back to a virulent form or a form that caused a disease.

因此,口服疫苗更加有效,因为它是活性病毒,但又是因为这一点,人们也存有更多顾虑,当它处于减毒状态时你会信任它,但是它会不会转变回,强毒壮态或者致病状态呢

耶鲁公开课 - 生物医学工程探索课程节选

The virus did not mutate to a more virulent form.

VOA: standard.2010.01.18

Angus Nicoll of the European Center for Disease Prevention says that at this point no one knows whether the virus will become more or less virulent in the months ahead.

VOA: standard.2009.04.30

It's a virulent strain that occurs when a person with TB fails to complete the six to nine-month course of medication or catches TB from another person who is ill with a drug resistant-strain.

VOA: standard.2010.07.12

that you are not as good. So the message of the Buffalo Soldiers is that in that time when racism was at its most virulent, that there were people, there were men who said, 'No,you're wrong, I am just as good as you are.

VOA: standard.2009.11.25

"Since we know that these kinds of threats can emerge at any moment, even if it turns out that the H1N1 is relatively mild on the front end, it could come back in a more virulent form during the actual flu season,"

VOA: standard.2009.05.01