Influenza A virus subtype H2N2 (A/H2N2) is a subtype of '' Influenza A virus''. H2N2 has mutated into various strains including the " Asian flu" strain (now extinct in the wild), H3N2, and various strains found in

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s. It is also suspected of causing a human pandemic in 1889. The geographic spreading of the 1889 Russian flu has been studied and published.

Russian flu

Some believe that the 1889–1890 Russian flu was caused by the influenzavirus A virus subtype H2N2, but the evidence is not conclusive. It is the earliest flu pandemic for which detailed records are available. More recently, there are speculations that it might have been caused by one of the coronaviruses first discovered in the 1960s.

Asian flu

The "Asian Flu" was a category 2 flu pandemic outbreak of influenzavirus A that first appeared in

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China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

in early 1957 and lasted until 1958. The first cases were reported in Singapore in February 1957. In February 1957, a new influenza A (H2N2) virus emerged in East Asia, triggering a pandemic (“Asian Flu”). This H2N2 virus was composed of three different genes from an H2N2 virus that originated from an avian influenza A virus, including the H2 hemagglutinin and the N2 neuraminidase genes. It was first reported in Singapore in February 1957, Hong Kong in April 1957, and in coastal cities in the United States in summer 1957. Some authors believe it originated from mutation in wild ducks combining with a pre-existing human strain. Other authors are less certain. It reached

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

by April, and US by June. Estimates of US and worldwide deaths caused by this pandemic varies widely depending on source; ranging from approximately 69,800 to 116,000 in the United States, and worldwide from 1 million to 4 million, with the

World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

(WHO) settling on "about 2 million," with an overall mortality rate of 0.6%. Asian Flu was of the H2N2 subtype (a notation that refers to the configuration of the hemagglutinin and

neuraminidase Exo-α-sialidase (, sialidase, neuraminidase; systematic name acetylneuraminyl hydrolase) is a glycoside hydrolase that cleaves the glycosidic linkages of neuraminic acids: : Hydrolysis of α-(2→3)-, α-(2→6)-, α-(2→8)- glycosidic linkag ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

s in the virus) of type A influenza, and an

influenza vaccine Influenza vaccines, colloquially known as flu shots or the flu jab, are vaccines that protect against infection by influenza viruses. New versions of the vaccines are developed twice a year, as the influenza virus rapidly changes. While their ...

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 influenza virus RNA segments. Influenza subtypes

Test kits

From October 2004 to February 2005, approximately 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 A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...

es; private contractor Meridian Bioscience in

Cincinnati Cincinnati ( ; colloquially nicknamed Cincy) is a city in Hamilton County, Ohio, United States, and its county seat. Settled in 1788, the city is located on the northern side of the confluence of the Licking River (Kentucky), Licking and Ohio Ri ...

, U.S., chose the 1957 strain instead of one of the less deadly avian influenza virus subtypes. The 1957 H2N2 virus is considered deadly and the U.S. government called for the vials containing the strain to be destroyed.

References

External links

Influenza Research Database
Database of influenza sequences and related information. {{DEFAULTSORT:Influenza A Virus Subtype H2n2 H2N2 1957 in Hong Kong 1889–1890 flu pandemic de:Asiatische Grippe es:Gripe asiática it:Influenza asiatica pt:Gripe asiática sv:Asiaten zh:亚洲流感

Russian flu

Asian flu

Test kits

References

Further reading

External links