Swine influenza (swine flu) is an acute viral infection of the respiratory tract in pigs caused by type A influenza virus.

猪流感是一种发生在猪身上的高度传染性急性呼吸道疾病，由A型流感病毒引起。

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First, let me clarify the difference between seasonal flu, avian flu, and human pandemic influenza.

首先，让我澄清季节性流感、禽流感与人类大流行性流感之间的区别。

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In the United States, cases of suspected influenza are at higher numbers than usual this early in the flu season.

VOA: special.2009.11.24

You've got the flu, you've got influenza in your upper respiratory tract, your cells are making more influenza.

你就此得了流感,你得了上呼吸道流感,你的细胞正在制造更多流感病毒

耶鲁公开课 - 生物医学工程探索课程节选

Viruses, you know about viruses; variola, we're going to talk about next week which causes smallpox, influenza, which causes the flu and HIV of course which cause AIDS are some examples.

病毒 你们都知道病毒,像天花病毒,我们下周会讲的引起天花的病毒,还有引起流感的流感病毒,引起艾滋病的人类免疫缺陷病毒等等

耶鲁公开课 - 生物医学工程探索课程节选

I'm glad you are thinking about ways to protect yourself from the flu (influenza) since the flu season can continue as late as May of each year, and immunization can prevent or lessen the severity of a case of the flu.

CNN: Is there an eggless flu shot?

He cited matters related to regional financial security and public health security such as the avian flu and influenza pandemics as examples of areas where more dynamism was needed.

CNN: Highlights from the world's press

The Google Cities flu tracker ranks influenza activity in each metropolis as low, moderate, high, or intense.

FORBES: The Worst U.S. Cities For The Flu Right Now