The subtypes, which had shown no pathogenicity in laboratory mice, were forced to evolve by serial passaging. H1n1 influenza or swine flu is a contagious disease that is caused by the influenza virus. The 2009 influenza pandemic was a recombinant influenza involving a mix of swine, avian, and human gene segments see h1n1 influenza swine flu. Influenza pneumonia incidence was high in 2005, a year when influenza ah3n2 subtype virus strains predominated, low in 2006 when a h1n1 viruses were more common, moderate in. However, after the 2009 pandemic, findings on the severity of epidemics by type and subtype of influenza virus have varied widely. Influenza a virus subtype h1n1 a h1n1 is the subtype of influenza a virus that was the most common cause of human influenza flu in 2009, and is associated with the 1918 spanish flu outbreak. The 2009 pandemic h1n1 is a new virus for updates, see. The association of certain influenza virus types and subtypes with disease severity has been a major topic of influenza research in recent years 410. This file contains additional information such as exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it.
This graphic shows the two types of influenza viruses a,b that cause most human illness and that are responsible for the flu season each year. The world health organization who declared the virus a global pandemic. The present invention provides an influenza a h1n1 subtype specific aptamer. This new h1n1 virus contained a unique combination of influenza genes not previously identified in animals or people. Humans can also be infected with influenza viruses that are routinely circulating in animals, such as avian influenza virus subtypes ah5n1 and ah9n2 and swine influenza virus subtypes a h1n1 and h3n2. Influenza a viruses are further classified into subtypes, while influenza b viruses are further classified into. In recent history, the most devastating example of a new subtype emerging in the human population was the 1918 influenza virus, which expressed a subtype 1 hemagglutinin protein h1 and a subtype 1 neuraminidase protein n1.
Types of influenza viruses cdc centers for disease control. All known subtypes of influenza a viruses can infect birds, except subtypes h17n10 and h18n11, which have only been found in bats. Influenzaviren gehoren zur familie orthomyxoviridae. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. This virus was designated as influenza a h1n1 pdm09 virus. The 1918 influenza pandemic was the most severe pandemic in recent history. Viral isolation, or culture, is currently the gold standard for diagnosis of influenza virus infections. As it was a novel strain of the virus, there was minimal immunity in the population. A look back at progress since the 2009 h1n1 pandemic. Other species including horses and dogs also have their own varieties of influenza viruses. The aptamer was selected in vitro using selex and a microfluidic chip system. Swine influenza the center for food security and public health.
S and others published swine flu and the current influenza a h1n1 pandemic in humans. It originated in pigs but is spread primarily from person. Illness severity in hospitalized influenza patients by. Pandemic preparedness in the workplace and the americans. For example, an h7n2 virus designates an influenza a virus subtype that has an ha 7 protein and an na 2 protein. It is an orthomyxovirus that contains the glycoproteins haemagglutinin and neuraminidase. Although there is not universal consensus regarding where the virus originated, it spread worldwide during 19181919. The 2009 flu pandemic in the united states was a novel strain of the influenza a h1n1 virus, commonly referred to as swine flu, that began in the spring of 2009. A small initial activity wave peaked in the week ending january 5, 2019, mmwr week 1, followed by a major activity wave, which peaked in the week ending february 6, 2019, mmwr week 6. In the spring of 2009, a novel influenza a h1n1 virus emerged. This h1n1 virus is estimated to have been responsible for 50 to 100 million deaths over a very short period of time. Influenza a straindependent pathogenesis in fatal h1n1. All structured data from the file and property namespaces is available under the creative commons cc0 license.
The 2009 h1n1 virus also does not fit the classic definition of drift because it has no direct evolutionary relationship with recently circulating h1n1 viruses of human origin. Although both adapted viruses evoked diffuse alveolar damage and showed a similar 50% mouse lethal. Webmd gives frank answers to questions about what we know, and dont know, about the pandemic flu vaccine. If pandemic influenza symptoms become more severe than the seasonal flu or the h1n1 virus in the springsummer of 2009, or if pandemic influenza becomes widespread in the community as assessed by state or local health authorities or the cdc, then.
Influenza virus aerosols in the air and their infectiousness. June 11, 2019 in 2009, a novel h1n1 influenza flu virus emerged to cause the first flu pandemic in 40 years. The strain of virus that caused the pandemic, influenza a virus subtype h2n2, was a recombination of avian influenza probably from geese and human influenza viruses. The genetic material originates from three different species.
Clinical management of human infection with pandemic. The virus had spread to the us from an outbreak in mexico. This virus was very different from the human influenza a. Us8835624b1 influenza a h1n1 subtypespecific aptamer. B in terms of prevalence, how contagious they are, what the vaccine covers, and severity and recovery. Neuraminidase beim influenza a virus bestimmt werden. The aptamer is stable, establishing sensitivity about 100 times higher than antibody and high specificity to influenza a h1n1 subtype.
In birds, humans, and pigs, the virus has mutated into many strains. The analyzed data were gathered from medical files and investigation reports from. A new strain of influenza a virus, with quadruple segment translocation in its rna, caused an outbreak of human infection in april 2009 in usa and mexico. The first cases were reported in guizhou in late 1956 or february 1957, and were reported in the neighboring province of yunnan. Influenza type confirmed by montana public health laboratory and partners. Influenza a virus subtype h3n2 ah3n2 is a subtype of viruses that causes influenza flu. In the united states, it was first identified in military personnel in spring 1918. Influenza virus concentration 2, 3, air circulation time, air temperature, and humidity play an important role in overcoming the epidemic threshold.
The virus was first recognized in april 2009 and spread quickly to 74 countries worldwide. Similarly, an h5n1 virus has an ha 5 protein and an na 1 protein. O impacto da infeccao pelo virus influenza a, subtipo h1n1, em pacientes. First, as the majority of human population has little or no preexisting immunity to the virus, the impact of the infection has been in a wider age. In the spring of 2009, a new influenza a h1n1 virus cdc 2009 h1n1 flu website emerged to cause illness in people. Swine flu, also known as the h1n1 virus, is a relatively new strain of an influenza virus that causes symptoms similar to the regular flu.
Influenza virus detections in the who european region from the start of reporting for the 2019 20 season weeks 40. Current subtypes of influenza a viruses found in people are influenza a h1n1 and influenza a h3n2 viruses. The influenza type a virus, known as h1n1 is a respiratory infection that was popularly named swine flu. The influenza subtype can be determined by a test called hemagglutination inhibition. Infection with the h1n1 influenza virus can result in severe illness and lifethreatening complications. Influenza virus h1n1 fact sheet morgridge institute for. Pathology and pathogenesis of 100 fatal cases in the united states. Australian product information fluad quad influenza. The term avian influenza, in this context, refers to zoonotic human infection with an influenza strain that primarily affects birds. Influenza virus particles are constantly circulating in the air airborne in different forms within dust particles or aerosol droplets 5, 6. Influenza the center for food security and public health iowa. Influenza virus is subtyped on the basis of surface glycoproteins. The 2009 h1n1 pandemic was estimated to be associated with 151,700 to 575,400 deaths worldwide during the first year it circulated.
In years in which h3n2 is the predominant strain, there are more hospitalizations. Crossreactive antibody responses to the 2009 pandemic h1n1 influenza virus external icon. It was detected first in the united states and spread quickly across the united states and the world. The pandemic h1n1 2009 influenza virus differs in its pathogenicity from seasonal influenza in two key aspects. Both of these activity waves were comprised primarily of influenza a 2009 h1n1 viruses. Antigenic and genetic characteristics of swineorigin 2009 a h1n1 influenza viruses circulating in humans pdf icon 327 mb, 7 pages external icon.
Other h1 viruses have not been detected since 2010. Thus, the aptamer can be effective in detection of h1n1 influenza virus. Files are available under licenses specified on their description page. The most common influenza subtype identified this week was influenza a h1n1 2009. It was caused by an h1n1 virus with genes of avian origin. The table presented below contains data for week 9 and the season to date. Its called swine flu because in the past, the people who caught it had direct contact with pigs. Swine influenza refers to infections from strains derived from pigs.
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