流行性感冒(简称流感)是由一种病毒引起的急性传染病。当病人传染上这种病快要发作和刚刚发作的时期,病人的口水和鼻涕里含有很多这种病毒。当病人咳嗽、打喷嚏或是谈话时,喷出的唾沫星子可能将病直接传染给与他近距离接触的人,或是通过碗筷、茶杯、手巾等东西,间接传染给别人。目前已经知道,引起流感的病毒有甲、乙、丙三种类型,达三种类型病毒所引起的病的症状没有什么区别;但是它们在免疫方面却 Influenza (flu) is an acute infectious disease caused by a virus. When the patient is infected with the disease is about to attack and just attack period, the patient’s saliva and the nose contains many of these viruses. When a patient coughs, sneezes, or talks, the spitting spit may be transmitted directly to someone in close contact with him or indirectly through someone else, such as a tableware, teacup, or towel. It is now known that there are three types of viruses that cause influenza, namely, A, B and C, and that there is no difference between the symptoms of the diseases caused by the three types of viruses; however, in terms of immunity,