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'''H2N2''' is a subtype of the species [[Influenzavirus A| Influenza A virus]] (sometimes called [[Avian flu|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 also suspected of causing a human pandemic in 1889.<ref> [http://scholar.google.com/scholar?hl=en&lr=&q=cache:vN-LnqPYDrgJ:biomicro.sdstate.edu/WangX/Micr425/Pathogenesis/Influenza_A.pdf+author:%22Hilleman%22+intitle:%22Realities+and+enigmas+of+human+viral+influenza:+...%22 Sdstate.edu]</ref><ref> [http://www.pilva.com/en/edoctor/article8.asp Pilva.com]</ref>

==Asian flu==
The "Asian Flu" was a [[Pandemic Severity Index|category 2]] [[flu pandemic]] outbreak of [[avian influenza]] that originated in China in early 1956 lasting until 1958. It originated from mutation in wild ducks combining with a pre-existing human strain.<ref name="Greene"> Greene Jeffrey. Moline, Karen. [2006] (2006) The Bird Flu Pandemic. ISBN 0312360568.</ref> The virus was first identified in Guizhou.<ref> Goldsmith, Connie. [2007] (2007) Influenza: The Next Pandemic?  21st century publishing.  ISBN 0761394575</ref> It spread to Singapore in February 1957, reached Hong Kong by April, and US by June. Death toll in the US was approximately 69,800.<ref name="Greene"/> Estimates of worldwide infection rate varies widely depending on source, ranging from 1 million to 4 million.

Asian Flu was of the H2N2 strain (a notation that refers to the configuration of the [[hemagglutinin]] and [[neuraminidase]] [[protein]]s in the virus) of [[avian influenza|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.<ref name="Starling"> Starling, Arthur. [2006] (2006) Plague, SARS, and the Story of Medicine in Hong Kong. HK University Press. ISBN 9622098053</ref>

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)." <ref> [http://www.influenzareport.com/ir/ai.htm 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.
</ref>

==Test kits==
From October 2004 to February 2005, some 3,700 test kits of the 1957 H2N2 virus were accidentally spread around the world from the [[College of American Pathologists]] (CAP). CAP assists laboratories in accuracy by providing unidentified samples of [[virus]]es; private contractor Meridian Bioscience in Cincinnati, U.S., chose the 1957 strand instead of one of the less deadly [[Influenzavirus A|avian influenza virus]] subtypes. "CAP spokesman Dr. Jared Schwartz said Meridian knew what the virus was but believed it was safe. In selecting it, the company had determined that the virus was classified as a biosafety level 2 (BSL-2) agent, which meant it could legally be used in the kits. [...] Before the problem came to light, the [[Centers for Disease Control and Prevention|CDC]] had made a recommendation that the H2N2 virus be reclassified as a BSL-3 agent, Gerberding said. She promised to speed up the reclassification. The CDC determines the classifications in collaboration with the [[National Institutes of Health]]. In BSL-3 labs, agents are handled with equipment designed to prevent any airborne contamination and resulting respiratory exposure."<ref> [http://www.cidrap.umn.edu/cidrap/content/influenza/panflu/news/april1305labs.html Cidrap UMN.edu]</ref> The 1957 H2N2 virus is considered deadly and the U.S. government called for the vials containing the strain to be destroyed.

"[[Centers for Disease Control and Prevention|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."<ref> [http://www.flu.org.cn/news/2005549988.htm Flu.org]</ref>

"In the [[United States]], there is no government regulation over the [[1957]] flu strain. In fact, federal officials at the [[Centers for Disease Control and Prevention|CDC]] do not even know how many U.S. laboratories keep this deadly strain in their ''viral libraries''."<ref> [http://www.theglobalist.com/DBWeb/StoryId.aspx?StoryId=4502 Globalist.com]</ref>

==Sources==
<references/>

==Further reading==
*[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12458361&dopt=Citation Pandemic preparedness: lessons learnt from H2N2 and H9N2 candidate vaccines]
*[http://www.cdc.gov/flu/h2n2bsl3.htm Interim CDC-NIH Recommendation for Raising the Biosafety Level for Laboratory Work Involving Noncontemporary Human Influenza Viruses]
*[http://www.newscientist.com/popuparticle.ns?id=in70 New Scientist: Bird Flu]
*[http://www.newscientist.com/article.ns?id=dn7261 Pandemic-causing 'Asian flu' accidentally released]
*[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6477129&dopt=Abstract Persistence of Q strain of H2N2 influenza virus in avian species: antigenic, biological and genetic analysis of avian and human H2N2 viruses]

{{Influenza}}

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[[Category:Influenza]]
[[Category:Pandemics]]
[[Category:Viruses]]
[[Category:Infectious disease]]


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