H2N2 is a subtype of the species Influenza A virus (sometimes called bird flu virus). H2N2 has mutated into various strains including the Asian Flu strain (now extinct in the wild), H3N2, and various strains found in birds.
It is suspected of causing a human pandemic in 1889. [http://www.pilva.com/en/edoctor/article8.asp
Asian Flu was of the H2N2 strain (a notation that refers to the configuration of the hemagglutinin and neuraminidase proteins in the virus) of type A influenza, and a flu vaccine was developed in 1957 to contain its outbreak.
The Asian Flu strain later evolved via antigenic shift into H3N2 which caused a milder pandemic from 1968 to 1969.
Both the H2N2 and H3N2 pandemic strains contained Avian flu virus RNA segments. "While the pandemic human influenza viruses of 1957 (H2N2) and 1968 (H3N2) clearly arose through reassortment between human and avian viruses, the influenza virus causing the 'Spanish flu' in 1918 appears to be entirely derived from an avian source (Belshe 2005)." Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner from excellent free on-line Book called Influenza Report 2006 which is a medical textbook that provides a comprehensive overview of epidemic and pandemic influenza.''
"CDC officials reported on April 21 that 99% of the samples had already been destroyed. News reports on April 25 said the last samples outside the United States had been destroyed at the American University of Beirut in Lebanon, after they were found at the Beirut airport. Earlier reports said H2N2 samples were sent to 3,747 labs under CAP auspices and to about another 2,700 labs certified by other organizations. All but about 75 labs that received the CAP samples were in the United States." *
"In the United States, there is no government regulation over the 1957 flu strain. In fact, federal officials at the CDC do not even know how many U.S. laboratories keep this deadly strain in their viral libraries." *
Asiatische Grippe | Gripe asiática | Influenza asiatica | H2N2 | Gripe asiática | Asiaten | 亚洲流感