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Influenza A(H1N1)
In virology, influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus. Major outbreaks of H1N1 strains in humans include the Spanish flu, the 1977 Russian flu pandemic and the 2009 swine flu pandemic. It is an orthomyxovirus that contains the glycoproteins hemagglutinin and neuraminidase. For this reason, they are described as H1N1, H1N2 etc., depending on the type of H or N antigens they express with metabolic synergy. Hemagglutinin causes red blood cells to clump together and binds the virus to the infected cell. Neuraminidase is a type of glycoside hydrolase enzyme which helps to move the virus particles through the infected cell and assist in budding from the host cells. Some strains of H1N1 are endemic in humans and cause a small fraction of all influenza-like illness and a small fraction of all seasonal influenza, for instance in 2004–2005. Other strains of H1N1 are endemic in pigs ( swine influenza) and in birds ( avian influenza). Its size i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pandemic H1N1/09 Virus
The pandemic H1N1/09 virus is a swine origin influenza A virus subtype H1N1 strain that was responsible for the 2009 swine flu pandemic. This strain is often called swine flu by the public media. For other names, see the Nomenclature section below. Viral characteristics The virus is a novel strain of the influenza virus, for which existing vaccines against seasonal flu provided no protection. A study at the U.S. Centers for Disease Control and Prevention (CDC) published in May 2009 found that children had no preexisting immunity to the new strain but that adults, particularly those over 60, had some degree of immunity. Children showed no cross-reactive antibody reaction to the then-new strain, while adults aged 18 to 64 had 6–9%, and older adults 34%. Much reporting of early analysis repeated that the strain contained genes from five different flu viruses: North American swine influenza, North American avian influenza, human influenza, and two swine influenza viruses typic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H1N2
Influenza A virus subtype H1N2 (A/H1N2) is a subtype of the species Influenza A virus (sometimes called bird flu virus). It is currently endemic in pig populations and is occasionally seen in humans. The virus does not cause more severe illness than other influenza viruses, and no unusual increases in influenza activity have been associated with it. __TOC__ History Between December 1988 and March 1989, 19 influenza H1N2 virus isolates were identified in 6 cities in China, but the virus did not spread further. A(H1N2) was identified during the 2001–02 flu season (northern hemisphere) in Canada, the U.S., Ireland, Latvia, France, Romania, Oman, India, Malaysia, and Singapore with earliest documented outbreak of the virus occurring in India on May 31, 2001. On February 6, 2002, the World Health Organization (WHO) in Geneva and the Public Health Laboratory Service (PHLS) in the United Kingdom reported the identification influenza A(H1N2) virus from humans in the UK, Israel, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History
History (derived ) is the systematic study and the documentation of the human activity. The time period of event before the History of writing#Inventions of writing, invention of writing systems is considered prehistory. "History" is an umbrella term comprising past events as well as the memory, discovery, collection, organization, presentation, and interpretation of these events. Historians seek knowledge of the past using historical sources such as written documents, oral accounts, art and material artifacts, and ecological markers. History is not complete and still has debatable mysteries. History is also an Discipline (academia), academic discipline which uses narrative to describe, examine, question, and analyze past events, and investigate their patterns of cause and effect. Historians often debate which narrative best explains an event, as well as the significance of different causes and effects. Historians also debate the historiography, nature of history as an end in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pandemic
A pandemic () is an epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. A widespread endemic (epidemiology), endemic disease with a stable number of infected individuals is not a pandemic. Widespread endemic diseases with a stable number of infected individuals such as recurrences of seasonal influenza are generally excluded as they occur simultaneously in large regions of the globe rather than being spread worldwide. Throughout human history, there have been a number of pandemics of diseases such as smallpox. The most fatal pandemic in recorded history was the Black Death—also known as Plague (disease), The Plague—which killed an estimated 75–200 million people in the 14th century. The term had not been used then but was used for later epidemics, including the 1918 influenza pandemic—more commonly known as the Spanish flu. Current pandemics include Epide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Journal Of Epidemiology
The American Journal of Epidemiology (''AJE'') is a peer-reviewed journal for empirical research findings, opinion pieces, and methodological developments in the field of epidemiological research. The current editor-in-chief is Dr. Enrique Schisterman. Articles published in ''AJE'' are indexed by PubMed, Embase, and a number of other databases. The ''AJE'' offers open-access options for authors. It is published monthly, with articles published online ahead of print at the accepted manuscript and corrected proof stages. Entire issues have been dedicated to abstracts from academic meetings (Society of Epidemiologic Research, North American Congress of Epidemiology), the history of the Epidemic Intelligence Service of the Centers for Disease Control and Prevention (CDC), the life of George W. Comstock, and the celebration of notable anniversaries of schools of public health ( University of California, Berkeley, School of Public Health; Tulane University School of Public Health and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies and autoimmune disorders. In humans, ''disease'' is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person affected, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection. Infections can be caused by a wide range of pathogens, most prominently bacteria and viruses. Hosts can fight infections using their immune system. Mammalian hosts react to infections with an innate response, often involving inflammation, followed by an adaptive response. Specific medications used to treat infections include antibiotics, antivirals, antifungals, antiprotozoals, and antihelminthics. Infectious diseases resulted in 9.2 million deaths in 2013 (about 17% of all deaths). The branch of medicine that focuses on infections is referred to as infectious disease. Types Infections are caused by infectious agents (pathogens) including: * Bacteria (e.g. ''Mycobacterium tuberculosis'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strain (biology)
In biology, a strain is a genetic variant, a subtype or a culture within a biological species. Strains are often seen as inherently artificial concepts, characterized by a specific intent for genetic isolation. This is most easily observed in microbiology where strains are derived from a single cell colony and are typically quarantined by the physical constraints of a Petri dish. Strains are also commonly referred to within virology, botany, and with rodents used in experimental studies. Microbiology and virology It has been said that "there is no universally accepted definition for the terms 'strain', ' variant', and 'isolate' in the virology community, and most virologists simply copy the usage of terms from others". A strain is a genetic variant or subtype of a microorganism (e.g., a virus, bacterium or fungus). For example, a "flu strain" is a certain biological form of the influenza or "flu" virus. These flu strains are characterized by their differing isoforms of su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2009 Flu Pandemic
The 2009 swine flu pandemic, caused by the H1N1 influenza virus and declared by the World Health Organization (WHO) from June 2009 to August 2010, is the third recent flu pandemic involving the H1N1 virus (the first being the 1918–1920 Spanish flu pandemic and the second being the 1977 Russian flu). The first two cases were discovered independently in the United States in April 2009. The virus appeared to be a new strain of H1N1 that resulted from a previous triple reassortment of bird, swine, and human flu viruses which further combined with a Eurasian pig flu virus, leading to the term "swine flu". Some studies estimated that the real number of cases including asymptomatic and mild cases could be 700 million to 1.4 billion people—or 11 to 21 percent of the global population of 6.8 billion at the time. The lower value of 700 million is more than the 500 million people estimated to have been infected by the Spanish flu pandemic. However, the Spanish flu infected approximat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoonosis
A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. Typically, the first infected human transmits the infectious agent to at least one other human, who, in turn, infects others. Major modern diseases such as Ebola virus disease and salmonellosis are zoonoses. HIV was a zoonotic disease transmitted to humans in the early part of the 20th century, though it has now evolved into a separate human-only disease. Most strains of influenza that infect humans are human diseases, although many strains of bird flu and swine flu are zoonoses; these viruses occasionally recombine with human strains of the flu and can cause pandemics such as the 1918 Spanish flu or the 2009 swine flu. ''Taenia solium'' infection is one of the neglected tropical diseases with public health and veterinary concern in en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H9N2
Influenza A virus subtype H9N2 (A/H9N2) is a subtype of the species Influenza A virus (bird flu virus). Since 1998 a total of 86 cases of human infection with H9N2 viruses have been reported. Infection in birds H9N2 is the most common subtype of influenza viruses in Chinese chickens and thus causes great economic loss for the poultry industry, even under the long-term vaccination programs. Recent human infections with avian influenza virus revealed that H9N2 is the gene donor for H7N9 and H10N8 viruses that are infecting humans too. The crucial role of H9N2 viruses due to the wide host range, adaptation to both poultry and mammals and extensive gene reassortment. In China, which is regarded as a breeding ground of avian influenza viruses, the H9N2 virus has been detected in multiple avian species, including chicken, duck, quail, pheasant, partridge, pigeon, silky chicken, chukar and egret. Epidemiological and genetic studies revealed that the hemagglutinin (HA) gene of the H9N2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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