As the flu virus attacks your respiratory system, a number of symptoms can start to reveal themselves.

当流感病毒攻击你的呼吸系统时，很多病症就是随之显现。

This virus attacks the weakest and most vulnerable and has thus disproportionately affected certain portions of the population.

这种病毒攻击最脆弱的群体，因此对特定人群造成了不成比例的影响。

When a virus attacks your body, your body works hard to get rid of it.

当病毒攻击您的身体时，您的身体会努力摆脱它。

Once infected,   the virus attacks the immune system; eventually, so much of the immune system  will be destroyed that the body cannot defend itself from illness.

一旦被感染，病毒就会攻击免疫系统；最终，如此多的免疫系统将被破坏，以至于身体无法保护自己免受疾病侵害。