Source for influenza pandemics

摘要: There are three ways how influenza A viruses can escape the immune response in human population: (1) By antigenic drift. This means by mutation and selection of variants under pressure system. These have amino acid replacements mainly epitopes hemagglutinin. (2) shift. replacement at least hemagglutinin gene prevailing strain allelic an avian virus reassortment. (3) As a rare event, direct or indirect introduction toto into population. prior pigs adaptation to new host might be presupposition for its final passage humans. In this sense nowadays situation is reminiscent that about 100 years ago, when was presumably first introduced pigs, from there Immediately some time thereafter disastrous Spanish Flu 1918/19 had killed 20,000,000 people one winter. Pandemic strains created all means, however most common way order recognize pandemic as soon possible worldwide surveillance system collaborating laboratories equipped with corresponding modern technologies required.