H9N2
Encyclopedia
H9N2 is a subtype of the species Influenza A virus
(bird flu virus).
"H9N2 influenza virus
es of domestic ducks have become established in the domestic poultry
of Asia
. Phylogenetic and antigenic analyses of the H9N2 viruses isolated from Hong Kong
markets suggest three distinct sublineages. Among the chicken
H9N2 viruses, six of the gene segments were apparently derived from an earlier chicken H9N2 virus isolated in China
, whereas the PB1 and PB2 genes are closely related to those of the H5N1
viruses and a quail
H9N2 virus A/quail/Hong Kong/G1/97 (Qa/HK/G1/97) suggesting that many of the 1997 chicken H9 isolates in the markets were reassortants."
"The National Institute of Allergy and Infectious Diseases
(NIAID), part of the National Institutes of Health
(NIH), has issued a task order under an existing contract to Chiron Corporation of Emeryville, CA, for the production of an investigational vaccine
based on an H9N2 strain of avian influenza virus that has infected human
s and has the potential to trigger a modern-day pandemic
.".
Over the years the H9N2 influenza strain caused illness in several children aged nine months to 5 years in Hong Kong
with the latest occurring in December 2009.
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...
(bird flu virus).
"H9N2 influenza 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 of domestic ducks have become established in the domestic poultry
Poultry
Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...
of Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. Phylogenetic and antigenic analyses of the H9N2 viruses isolated from 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...
markets suggest three distinct sublineages. Among the chicken
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...
H9N2 viruses, six of the gene segments were apparently derived from an earlier chicken H9N2 virus isolated 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...
, whereas the PB1 and PB2 genes are closely related to those of the H5N1
H5N1
Influenza A virus subtype H5N1, also known as "bird flu", A or simply H5N1, is a subtype of the influenza A virus which can cause illness in humans and many other animal species...
viruses and a quail
Quail
Quail is a collective name for several genera of mid-sized birds generally considered in the order Galliformes. Old World quail are found in the family Phasianidae, while New World quail are found in the family Odontophoridae...
H9N2 virus A/quail/Hong Kong/G1/97 (Qa/HK/G1/97) suggesting that many of the 1997 chicken H9 isolates in the markets were reassortants."
"The National Institute of Allergy and Infectious Diseases
National Institute of Allergy and Infectious Diseases
The National Institute of Allergy and Infectious Diseases is one of the 27 institutes and centers that make up the National Institutes of Health , an agency of the United States Department of Health and Human Services...
(NIAID), part of 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...
(NIH), has issued a task order under an existing contract to Chiron Corporation of Emeryville, CA, for the production of an investigational vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
based on an H9N2 strain of avian influenza virus that has infected human
Human
Humans are the only living species in the Homo genus...
s and has the potential to trigger a modern-day pandemic
Pandemic
A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic...
.".
Over the years the H9N2 influenza strain caused illness in several children aged nine months to 5 years in 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...
with the latest occurring in December 2009.
Further reading
- Centers for Disease Control and Prevention (CDC) - Influenza A(H9N2) infections in Hong Kong published April 8, 1999.
- People's Daily Online - Hong Kong reports human case of H9N2 published March 20, 2007.
- Xinhua News Agency - HK girl infected with rare but mild A/H9N2 flu virus published December 23, 2009.
External links
- Influenza Research Database Database of influenza genomic sequences and related information.