[History of influenza virus research].

I divided the history of influenza virus research into four groups according to the development of analysis methods. Since isolation of human influenza virus in 1933, many works have been done. However, under the limitation of analysis method, progress in knowledge about influenza virus was very slow and many questions remained until the molecular biological methods were developed. After 1975, by using molecular biological methods, influenza virus research progressed rapidly. Especially, by the application of PCR method, followed by capillary autosequencer, the research of influenza virus genome developed rapidly. Now, we can handle the influenza virus by manipulation of cloned cDNAs by reverse genetics.