普通感冒是由鼻病毒、冠状病毒等多种病原体引起的急性呼吸道传染病；流行性感冒的罪魁祸首则是流感病毒。对于患者而言,流感的危险之处在于它严重的并发症和高死亡率；对于大众,危险则在于它强烈的传染性,它可以通过飞沫迅速传播甚至引起爆发。有时一个地区发生了流感,几个小时后,流感病毒就会随着飞机、火车、汽车被携带到另一个地区。 The common cold is caused by rhinovirus, coronavirus and other pathogens of acute respiratory diseases; the culprit of influenza is the influenza virus. For patients, the danger of the flu is its serious complications and high mortality; for the general public, the danger is that it is highly contagious, it can spread rapidly through the droplets and even cause an outbreak. Sometimes flu occurs in one area and in a few hours the flu virus can be carried along with planes, trains and cars to another area.