Scholtissek C
Institut für Virologie, Justus Liebig Universität, Giessen, Germany.
Eur J Epidemiol. 1994 Aug;10(4):455-8. doi: 10.1007/BF01719674.
There are three ways how influenza A viruses can escape the immune response in the human population: (1) By antigenic drift. This means by mutation and selection of variants under the selection pressure of the immune system. These variants have amino acid replacements mainly in the epitopes of the hemagglutinin. (2) By antigenic shift. This means replacement of at least the hemagglutinin gene of the prevailing human strain by the allelic gene of an avian influenza virus by reassortment. (3) As a rare event, direct or indirect introduction of an avian influenza virus in toto into the human population. A prior introduction of an avian virus into pigs and an adaptation to the new host might be a presupposition for its final passage to humans. In this sense the nowadays situation is reminiscent to that of about 100 years ago, when an avian virus was presumably first introduced into pigs, and from there into humans. Immediately or some time thereafter the disastrous Spanish Flu in 1918/19 had killed at least 20,000,000 people in one winter. Pandemic strains can be created by all three means, however the most common way is by reassortment. In order to recognize a pandemic strain as soon as possible a worldwide surveillance system and collaborating laboratories equipped with corresponding modern technologies are required.
（1）通过抗原漂移。这意味着在免疫系统的选择压力下通过变异和变体选择。这些变体主要在血凝素的表位中有氨基酸替换。（2）通过抗原转变。这意味着通过重配，流行的人类毒株的至少血凝素基因被禽流感病毒的等位基因所取代。（3）作为一种罕见事件，禽流感病毒整体直接或间接引入人群。事先将禽流感病毒引入猪并使其适应新宿主可能是其最终传播给人类的一个前提条件。从这个意义上说，如今的情况让人想起大约100年前的情况，当时一种禽流感病毒大概首先被引入猪，然后从那里传播给人类。紧接着或此后不久，1918/19年灾难性的西班牙流感在一个冬天就造成至少2000万人死亡。大流行毒株可以通过所有这三种方式产生，然而最常见的方式是通过重配。为了尽快识别大流行毒株，需要一个全球监测系统以及配备相应现代技术的合作实验室。
