一.流行性感冒为何引起世界范围的大流行? 流行性感冒病毒是引起流行性感冒(简称流感)的主要病原体,它属RNA病毒的粘病毒属,流感病毒根据核蛋白的抗原不同,可分为甲、乙、丙三型,病毒的表面抗原包括凝血素和神经氨酸酶,极不稳定,常发生变异.流感的流行与病毒变异有关,以甲型病毒变异最为突出。现知甲型流感病毒由八个或八个以上RNA节段所组成,每一个节段为决定一种结构或功能蛋白质基因组,而这些节段可以自由组合,这就造成甲型流感病毒之所以容易发生突变的原因,也是甲型流感病毒亚型划分的主要依据.甲型流感病毒从1933年被分离出来后,至今已有数次大的变异和小的 Why influenza causes the worldwide pandemic? Influenza virus is the major cause of influenza (influenza), which belongs to the genus Mycoplasma RNA virus, influenza virus according to different nuclear antigen can be divided For the A, B, C three types of virus surface antigen, including hemagglutinin and neuraminidase, very unstable, often mutation. Influenza prevalence and virus variants related to the most prominent mutation of the A virus. Now that the influenza A virus consists of eight or more RNA segments, each segment is to determine a structure or function of the protein genome, and these segments can be freely combined, which led to the reason why the influenza A virus Prone to mutation, is also the main basis for the subtype of influenza virus type A. Since the influenza A virus was isolated in 1933, there have been several major changes and small