There are many different strains of flu virus.

有许多不同类型的流感病毒。

《柯林斯英汉双解大词典》

Harry is a flu virus and he's a dangerous little guy.

哈里是流感病毒，是个危险的小家伙。

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Anyone, once tested positive for H7N9 flu virus, will receive free medical treatment from our government.

任何人一旦被检测出感染H7N9禽流感病毒，都将得到政府资助的免费治疗。

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As of Tuesday, seventy-three countries had reported more than twenty-six thousand cases of the new H1N1 flu virus.

VOA: special.2009.06.10

The most common seasonal flu virus found in the United States this year is type A(H1N1).

VOA: special.2009.03.04

But experts say it has become the leading flu virus in all countries.

VOA: special.2009.11.24

Traditionally, vaccines were manufactured from the complete organism, such as an inactivated flu virus.

FORBES: Breakthrough Technologies For 2008

Or you may be exposed to a flu virus that is not included in the vaccine.

CNN: Flu shot myths addressed

The organism Ignacio Cirac and Oriol Romero-Isart have in mind is the flu virus.

ECONOMIST: An old thought experiment may soon be realised