H2N2
Encyclopedia
H2N2 is a subtype of the type influenzavirus A
. H2N2 has mutated into various strains including the Asian flu strain (now extinct in the wild), H3N2
, and various strains found in bird
s. It is also suspected of causing a human pandemic in 1889.
The geographic spreading of the 1889 Russian flu have been studied and published.
Asian flu pandemic outbreak of influenza A virus originated in China
in early 1956, and lasted until 1958. Some authors believe it originated from a mutation in wild duck
s combining with a pre-existing human strain. Other authors are less certain. The virus was first identified in Guizhou
. It spread to Singapore
in February 1957, reached Hong Kong
by April, and the US by June. The death toll in the US was about 69,800. Estimates of worldwide deaths caused by this pandemic varies widely depending on source, ranging from one to four million, with WHO settling on "about two million".
Asian flu was of the H2N2 subtype (a notation that refers to the configuration of the hemagglutinin
and neuraminidase
protein
s in the virus) of type A influenza, and an influenza 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 influenza 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)."
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
es; private contractor Meridian Bioscience in Cincinnati, U.S., chose the 1957 strand instead of one of the less deadly 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 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." The 1957 H2N2 virus is considered deadly and the U.S. government called for the vials containing the strain to be destroyed.
"CDC
officials reported on 21 April that 99% of the samples had already been destroyed. News reports on 25 April 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."
Influenzavirus A
Influenza A virus causes influenza in birds and some mammals and is the only species of Influenzavirus A. Influenzavirus A is a genus of the Orthomyxoviridae family of viruses. Strains of all subtypes of influenza A virus have been isolated from wild birds, although disease is uncommon...
. H2N2 has mutated into various strains including the Asian flu strain (now extinct in the wild), H3N2
H3N2
Influenza A virus subtype H3N2 is a subtype of viruses that cause influenza . H3N2 Viruses can infect birds and mammals. In birds, humans, and pigs, the virus has mutated into many strains...
, and various strains found in bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. It is also suspected of causing a human pandemic in 1889.
The geographic spreading of the 1889 Russian flu have 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. "The 1889 pandemic, known as the Russian Flu, began in Russia and spread rapidly throughout Europe. It reached North America in December 1889 and spread to Latin America and Asia in February 1890. About 1 million people died in this pandemic."Asian flu
The category 2Pandemic Severity Index
The Pandemic Severity Index is a proposed classification scale for reporting the severity of influenza pandemics in the United States. The PSI was accompanied by a set of guidelines intended to help communicate appropriate actions for communities to follow in potential pandemic situations...
Asian flu pandemic outbreak of influenza A virus originated in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
in early 1956, and lasted until 1958. Some authors believe it originated from a mutation in wild duck
Wild duck
Wild Duck can refer to:*The Wild Duck, play by Henrik Ibsen*mallard, species of wild duck...
s combining with a pre-existing human strain. Other authors are less certain. The virus was first identified in Guizhou
Guizhou
' is a province of the People's Republic of China located in the southwestern part of the country. Its provincial capital city is Guiyang.- History :...
. It spread to Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
in February 1957, reached Hong Kong
Hong Kong
Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
by April, and the US by June. The death toll in the US was about 69,800. Estimates of worldwide deaths caused by this pandemic varies widely depending on source, ranging from one to four million, with WHO settling on "about two million".
Asian flu was of the H2N2 subtype (a notation that refers to the configuration of the hemagglutinin
Hemagglutinin
Influenza hemagglutinin or haemagglutinin is a type of hemagglutinin found on the surface of the influenza viruses. It is an antigenic glycoprotein. It is responsible for binding the virus to the cell that is being infected...
and neuraminidase
Neuraminidase
Neuraminidase enzymes are glycoside hydrolase enzymes that cleave the glycosidic linkages of neuraminic acids. Neuraminidase enzymes are a large family, found in a range of organisms. The most commonly known neuraminidase is the viral neuraminidase, a drug target for the prevention of the spread...
protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s in the virus) of type A influenza, and an influenza vaccine was developed in 1957 to contain its outbreak.
The Asian flu strain later evolved via antigenic shift
Antigenic shift
Antigenic shift is the process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains...
into H3N2
H3N2
Influenza A virus subtype H3N2 is a subtype of viruses that cause influenza . H3N2 Viruses can infect birds and mammals. In birds, humans, and pigs, the virus has mutated into many strains...
, which caused a milder pandemic from 1968 to 1969.
Both the H2N2 and H3N2 pandemic strains contained avian influenza 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)."
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
College of American Pathologists
The College of American Pathologists , is a medical society serving more than 17,000 physician members and the laboratory community throughout the world....
(CAP). CAP assists laboratories in accuracy by providing unidentified samples of virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es; private contractor Meridian Bioscience in Cincinnati, U.S., chose the 1957 strand instead of one of the less deadly avian influenza virus
Influenzavirus A
Influenza A virus causes influenza in birds and some mammals and is the only species of Influenzavirus A. Influenzavirus A is a genus of the Orthomyxoviridae family of viruses. Strains of all subtypes of influenza A virus have been isolated from wild birds, although disease is uncommon...
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 CDC
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
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
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
. In BSL-3 labs, agents are handled with equipment designed to prevent any airborne contamination and resulting respiratory exposure." The 1957 H2N2 virus is considered deadly and the U.S. government called for the vials containing the strain to be destroyed.
"CDC
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
officials reported on 21 April that 99% of the samples had already been destroyed. News reports on 25 April said the last samples outside the United States had been destroyed at the American University of Beirut in Lebanon
Lebanon
Lebanon , officially the Republic of LebanonRepublic of Lebanon is the most common term used by Lebanese government agencies. The term Lebanese Republic, a literal translation of the official Arabic and French names that is not used in today's world. Arabic is the most common language spoken among...
, 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
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
do not even know how many U.S. laboratories keep this deadly strain in their viral libraries."
Further reading
- Pandemic preparedness: lessons learnt from H2N2 and H9N2 candidate vaccines
- Interim CDC-NIH Recommendation for Raising the Biosafety Level for Laboratory Work Involving Noncontemporary Human Influenza Viruses
- New Scientist: Bird Flu
- Pandemic-causing 'Asian flu' accidentally released
- Persistence of Q strain of H2N2 influenza virus in avian species: antigenic, biological and genetic analysis of avian and human H2N2 viruses
External links
- Influenza Research Database Database of influenza sequences and related information.