The virus involved in the spring 2009 global influenza outbreak is a new strain of influenza virus affecting humans. Although referred to as swine influenza in many reports, scientific evidence shows that it. Oseltamivirresistant influenza viruses a h1n1 orvs with h275y mutation in the neuraminidase emerged independently of drug use. Evolution of a pandemic ah1n1 2009, april 2009 august 2010, 2nd edition. On 11 june 2009, who declared that an influenza pandemic was underway phase 6 because sustained humantohuman transmission was occurring at the community level in countries in two or more who regions. During the spring of 2009, a novel influenza a h1n1 virus of swine origin caused.
H3n2 canine influenza virus with the matrix gene from the. As of march 2010, illness caused by the 2009 h1n1 virus had occurred in almost all countries, with more than 16,000 deaths from laboratoryconfirmed cases reported to the world health organization. Clinical aspects of pandemic 2009 influenza a h1n1 virus infection. Dr shankar was a member of the regional response team for influenza ah1n1 pdm09 virus infection in the west midlands. Strains of flu virus differ from one another largely in the genes that code for surface molecules called glycoproteins, which are the primary targets of the bodys immune system in defending against flu viruses. Characteristics of novel ah1n1 viruscharacteristics of novel ah1n1 virus transmission of novel ah1n1 is similar to seasonal influenza clinical signs and symptoms similar to seasonal influenza, but with higher rates of nauseavomiting and diarrhea novel ah1n1 is genetically different from the ah1n1 strain included in seasonal influenza vaccines. News about swine flu h1n1 virus, including commentary and archival articles published in the new york times. Within a short time of the initial emergence of ah1n1pdm09 virus, novel reassortants were isolated from swine.
Ah1n1 pdm09 to distinguish it from the seasonal influenza ah1n1 viruses that circulated prior to the pandemic. It was called swine flu early on because tests showed that it was like flu viruses that occur in swine pigs. An influenza pandemic can happen when a novel flu virus emerges, such as a swine flu. This virus was designated as influenza a h1n1pdm09 virus. The influenza virus belongs to orthomyxoviridae family. It is an orthomyxovirus that contains the glycoproteins haemagglutinin and neuraminidase. In 2009 a strain of swine flu called h1n1 infected many people around the world. In the spring of 2009, a novel influenza a h1n1 virus emerged. The 2009 swine flu pandemic was an influenza pandemic that lasted for about 20 months, from january 2009 to august 2010, and the second of the two pandemics involving h1n1 influenza virus the first being the 19181920 spanish flu pandemic, albeit a new strain. A and b which only infect humans and c which is uncommon. Swine flu is an influenza virus that usually affects pigs.
In europe, the 200708 winter season was dominated by influenza virus a h1n1 circulation through week 7, followed by influenza b virus from week 8 onward. Residents of states with ah1n1 cases cdc has identified human cases of ah1n1 virus infection in people in the u. The influenza virus leads to respiratory disease that. We aimed to estimate the global number of deaths during the first 12. Shipment procedures are the same as those used by nics for seasonal influenza specimens. This new h1n1 virus contained a unique combination of influenza genes not previously identified in animals or people. This article offers a summarized vision of the main. After an outbreak of pandemic influenza ah1n1 ph1n1 virus, we had previously reported the emergence of a recombinant canine influenza virus civ between the ph1n1 virus and the classic h3n2 civ. Current estimates of the secondary attack rate of h1n1 range from 22% to 33%. This variant was soon designated as swine flu virus although it was never detected in porcine populations until the occurrence in a swine herd in alberta, canada in may 2009, in.
First described in april 2009, the virus appeared to be a new strain of h1n1, which resulted from a previous triple reassortment of. Pdf influenza ah1n1 pdm09 virus in pigs, reunion island. Today we talk about the influenza virus, how dangerous is it, how it invades us, its roll as a cause of pneumonia and how we may protect us from it. The influenza type a virus, known as h1n1 is a respiratory infection that was popularly named swine flu. The world health organization who declared the virus a global pandemic.
It has become the dominant strain in the southern hemisphere, where the influenza season has now ended. The hospitalisation rate during the 20092010 season was 5. Estimated global mortality associated with the first 12. Its called swine flu because in the past, the people who caught it had direct contact with pigs. H1n1 medical definition merriamwebster medical dictionary. Treatment and prevention of pandemic h1n1 influenza. Reassortment of strains of influenza a h1n1 of avian, porcine and human origin. Pandemic influenza 2009 is an animal influenza virus that emerged in the americas in early 2009.
Influenza is an acute respiratory illness, caused by influenza a, b, and c viruses, that occurs in local outbreaks or seasonal epidemics. Clinical aspects of pandemic 2009 influenza a h1n1 virus. Swine influenza is a respiratory disease of pig caused by type a. Hospitalization and deaths have occurred as a result of illness associated with this virus. It was detected first in the united states and spread quickly across the united states and the world. Because this virus is very different from current seasonal influenza viruses, many people will not have protective immunity against it and the seasonal flu vaccine will not protect against it either. Influenza viruses are cultured in chick embryo and cell culture mdck. Ah1n1 virus swine flu influenza ah1n1 ah1n1 pandemic. The emergence and transition to pandemic status of the influenza ah1n1ah1n1pdm09 virus in 2009 illustrated the potential for previously circulating human viruses to reemerge in humans and cause a pandemic after decades of circulating among animals. Oseltamivirresistant influenza virus a h1n1, europe.
With an ability to spread from persontoperson, the virus spread globally causing mild to severe illness. Oleh sebab itu, kandungan tersebut dideskripsikan sebagai h1n1, h1n2, dan. Cdc is working with local and state health agencies to investigate these cases. People do not normally get swine flu, but human infections can and do happen. For influenza a viruses, the hemagglutinin and neuraminidase antigen description are provided in parentheses e. The clinical spectrum of disease caused by the swineorigin 2009 ah1n1 influenza virus and its transmissibility are not completely understood.
Our ongoing routine surveillance isolated another reassortant h3n2 civ carrying the matrix gene of the ph1n1 virus from 2012. Predominance of influenza ah1n1pdm09 virus genetic subclade 6b. Influenza a viruses can also cause sporadic infections or spread worldwide. All influenza viruses of significance in swine are type a, subtype h1n1, h1n2, or h3n2 viruses. Swine influenza is a respiratory disease common among pigs caused by type a influenza, principally subtypes h1n1, h1n2, h2n1, h3n1, h3n2, and h2n3. In virology, influenza a virus subtype h1n1 ah1n1 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 flu pandemic. Virus influenza a h1n1 merupakan virus influenza a yang umumnya menyebabkan flu kepada manusia pada tahun 2009, dan virus ini erat kaitannya dengan penyebaran virus flu spanyol pada tahun 1918 virus ini merupakan orthomiksovirus yang mengandung glikoprotein hemaglutinin dan neuraminidase. The pandemic influenza ah1n1 2009 virus was confirmed in all deceased patients. Clinical illness follows a short incubation period and presentation ranges from asymptomatic to fulminant, depending on the characteristics of both the virus and the individual host. The first outbreak occurred in 2009 and infected people all over the world. H1n1 appears to be more contagious than seasonal influenza, the who said in an online statement released today. Influenza ah1n1 pdm09 virus in pigs, reunion island article pdf available in emerging infectious diseases 1810. This number is likely to be only a fraction of the true number of the deaths associated with 2009 pandemic influenza a h1n1. His areas of interest include control of communicable diseases, surveillance, vaccine preventable diseases, and the epidemiology of health careassociated infections.
H1n1 flu more contagious than seasonal virus cidrap. Pandemic 2009 h1n1 virus derives six genes from triplereassortant north ameri. However, just as the common, seasonal flu that affects humans is constantly mutating as our immune systems and vaccines compromise weaker strains, swine flu is always trying to improve itself so that it can become more virulent, spread faster. The virus was first recognized in april 2009 and spread quickly to 74 countries worldwide. What the response to pandemic a h1n1 has highlighted is that advances.
Its genetic material is made up of eight separate segments. The influenza a h1n1 virus is a member of the family orthomyxoviridae a group of rna viruses. Where are we in our understanding of the association between narcolepsy and one of the 2009 adjuvanted influenza a h1n1 vaccines. The secondary attack rate of seasonal influenza ranges from 5% to 15%. By country, the proportion of orvs ranged from 0% to 68%, with the highest proportion in norway. Influenza ah1n1pdm09 virus ph1n1 was the causal factor of the recent flu pandemic, which claimed several hundred lives. Influenza virus h1n1 fact sheet morgridge institute for. This virus was designated as influenza a h1n1 pdm09 virus. Influenza is unpredictable, but this flu season could be worse than recent years because of the 2009 h1n1 virus. That changed several years ago, when a new virus emerged that. The virus is contagious and can spread from human to. Influenza a h1n1, virus that is best known for causing widespread outbreaks, including epidemics and pandemics, of acute upper or lower respiratory tract infection. Pandemic influenza a h1n1 2009 pandemic h1n1 is spreading throughout the planet.
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