Using HPCs from umbilical cords and commercial LABS, the researchers demonstrated in test-tube experiments that the virus not only infected the cells but also could remain latent.

研究人员使用脐带中和盈利性实验室里的定向造血干细胞，通过在试管中进行试验演示出，病毒不但可以感染细胞而且还能保持潜伏状态。

youdao

A person needs only to breathe in a small number of these germs to become infected (although only a small proportion of people will become infected with TB disease).

人只要吸入少量这些病菌，即受到感染(虽然只有少数人感染结核病)。

youdao

However, the weight gain was not permanent in every case, lasting only long enough for the infected person to build up resistance to the virus.

然而，这种原因的体重的增加都不是永久的，它只会持续到感染者有能力足以抵抗该病毒为止。

youdao

The experts said you could get infected only if you sit within two rows of someone who is sick.

VOA: special.2009.07.14

This study shows that not only is it better for the person who is infected, but it helps that person from transmitting to the person that's their sexual partner, heterosexual partner."

VOA: special.2011.05.18

The outbreak of severe acute respiratory syndrome, or SARS, in Asia in 2003 only infected around 8, 000 people and killed about a tenth of these.

ECONOMIST: The spreading bird-flu menace reaches Europe | The

Users' machines will only be infected if they open and run the attachment bearing the worm.

BBC: The Bagle virus has tricked lots of people

It came back negative, which can happen with people infected only recently.

WSJ: TB's Global Resurgence Amplifies U.S. Risk