Pathogenesis of influenza a virus infection in swine. The annual influenza disease burden in the human population remains significant even with current vaccine usage, and much about the pathogenesis and. Cytokines and acute phase proteins during the acute stage of a swine 65. Swine influenza is an infection caused by any one of several types of swine influenza viruses.
Pathogenesis of african swine fever in domestic pigs and. This novel influenza 2009ah1n1 virus contains a combination of 2 swine, one avian and one human influenza virus genes. The ha plays a central role in the pathogenicity of ai viruses, as. Esterhuysenan investigation into natural resistance to african swine fever in domestic pigs from an endemic area in southern. Genesis and pathogenesis of the 1918 pandemic h1n1. The bird flu virus affects all systems of human body the main symptoms of swine influenza are vomiting and diarrhea. Pathogenesis and transmission of the novel swineorigin influenza virus ah1n1 after experimental infection of pigs elke lange 1, donata kalthoff 2, ulrike blohm 1, jens p. Swine influenza, also called swine flu, hog flu, and pig flu, refers to influenza caused by those strains of influenza virus, called swine influenza virus swine influenza virus, that usually infect pigs. Influenza is an acute respiratory illness, caused by influenza a, b, and c viruses, that occurs in local outbreaks or seasonal epidemics. We find that the resulting pandemic virus jumped directly to swine but was likely displaced in humans by.
To better understand this deadly virus, an expert group of researchers and virus hunters set out to search for the lost 1918 virus, sequence its genome, recreate the virus in a highly safe and regulated laboratory setting at cdc, and ultimately study its secrets to better prepare for future pandemics. Gruys summary swine influenza is a highly infectious viral disease of pigs, causing considerable economic impact. Swine flu is a respiratory disease of pigs caused by type a influenza that cause outbreaks in pigs regularly. The purpose of this study was to elucidate pathogenesis and viral distribution in pigs infected with swine influenza virus subtype h1n2, over a period of 10 days, by morphometric analysis and insitu hybridization. The 1918 influenza pandemic virus caused severe pneumonia, resulting in an estimated 50 million deaths worldwide. Pigs are the principal hosts of classic swine influenza virus. Prior to 2009, the largest cluster of h1n1 swine influenza cases.
A 3d medical animations illustrating how swine flu h1n1 influenza virus infects the respiratory system and attacks the healthy cells. This influenza commonly occurs in people exposed to infected pigs, or person to person. However, if the virus is similar enough to have crossreaction, the infection can be reduced to as few as 24 days. Pathogenesis of pandemic influenza a h1n1 and triple. The swineorigin ah1n1 influenza virus that has emerged in humans in early 2009 has raised concerns about pandemic developments. Download chapter pdf viral replication damages its infected cells to cause their apoptosis, which is the underlying mechanism of its pathogenesis. Other species including horses and dogs also hav e their own varieties of influenza viruses. Swine influenza is an acute, highly contagious, respiratory disease that results from infection with type a influenza virus. Pathogenesis and vaccination of influenza a virus in swine. This work is licensed under a creative commons attribution. Influenza has been recognized as a respiratory disease in swine since its first appearance concurrent with the 1918 spanish flu human. Transmission and pathogenesis of swineorigin 2009 ah1n1. Like human influenza viruses, there are different subtypes and strains of swine influenza viruses. The 1918 h1n1 flu virus caused the deadliest pandemic of the 20th century.
Veterinary pathology influenza a virus infections in swine. Interspecies transmission of reassortant swine influenza a virus containing genes from swine influenza ah1n1pdm09 and ah1n2 viruses. Greigpathogenesis of african swine fever in pigs naturally exposed to the. Clinical illness follows a short incubation period and presentation ranges from asymptomatic to fulminant, depending on the. Swine flu virus affects only the respiratory system.
Swineflu influenza h1n1 mechanism of action moa animation. Swine flu is considered a variant virus because it normally circulates in pigs and not people. Swine influenza respiratory system merck veterinary manual. The clinical manifestations, diagnosis, treatment, and prevention of avian influenza are discussed although the emergence of pandemic h1n1 influenza in north america in 2009 has demonstrated the variable nature of influenza viruses and the need for virologic. Pdf pathogenesis and transmission of swineorigin 2009 a. Avian influenza viruses have been detected a number of times in asian pigs. All other viruses are low pathogenic lp and cause a much milder, primarily res piratory disease. Pathogenesis and epidemiology of swine influenza virus. Swine influenza refers to infections from strains derived from pigs. Volunteers were infected with influenza virus by intranasal instillation, and virus titers were determined in daily nasal washes.
The classical swine flu virus, an influenza type a h1n1 virus was first isolated from a pig in 1930. Influenza virology and animal transmission studies antigenic and genetic characteristics of swineorigin 2009 ah1n1 influenza viruses circulating in humans pdf icon 327 mb, 7 pages external icon. H1n1 influenza swine flu statpearls ncbi bookshelf. The evolution and epidemiology of influenza a virus iav infections in swine have been integrally tied to the segmented nature of the genome of the virus, which facilitates gene reassortment, and to the adaptability of these genes through mutation, which sometimes facilitates replication in a new host. Swine influenza is an acute and highly contagious respiratory disease of swine caused by the orthomyxovirus. Initially recognised in mexico, swine flu or h1n1 influenza was declared as a pandemic by who on june 11, 2009. Pathogenesis and transmission of the novel swineorigin. In 1976, swine influenza virus caused a respiratory illness with one fatality among soldiers in fort dix, new jersey. Pdf the objective of this study is to investigate the pathogenesis of swine influenza virus siv subtype h1n1 and h3n2 thai isolates in 22dayold. Creative commons attributionnoncommercialsharealike license.
Once influenza virus gains its access to human respiratory tract, it adheres to and penetrates into. In a ferret pathogenesis and transmission model, the 2009 ah1n1 influenza virus was found to be more pathogenic than a seasonal ah1n1 virus, with more extensive virus replication occurring in the respiratory tract. First described in april 2009, the virus appeared to be a new strain of h1n1 which. Its called swine flu because in the past, the people who caught it had direct contact with pigs. In this area of the globe, there are several subtypes of iavs circulating in swine populations, including the 2009 ph1n1, but there are still many research gaps in the epidemiology of the disease. Pdf pathogenesis and vaccination of influenza a virus in. Avian and swine influenza viruses veterinary research, a journal. Pathogenesis and epidemiology of swine influenza virus 2 nd international conference on flu october 31november 02, 2016 san francisco, usa. Pathogenesis and transmission of swineorigin 2009 a h1n1 influenza virus in ferrets. When influenza virus is introduced into the respiratory tract, by aerosol or by contact with saliva or other respiratory secretions from an infected individual, it attaches to and replicates in epithelial cells. Swine influenza is a respiratory disease of pigs caused by type a influenza viruses that regularly cause outbreaks of influenza in pigs. Swine influenza is known to be caused by influenza a subtypes h1n1, h1n2, h3n1, h3n2, and h2n3.
The h1n1infected pigs had greater lung lesion scores than those of the h3n2infected pigs. Familiarity with the organization of the manual will make it more useful. Pathogenesis and transmission of swineorigin 2009 ah1n1. The table of contents lists the diseases and conditions of swine covered in this manual. As of 2009, the known siv strains include influenza c and the subtypes of influenza a known as h1n1, h1n2, h2n1, h3n1, h3n2, and h2n3. The pandemic h1n1 2009 influenza virus differs in its pathogenicity from seasonal influenza in two. Pathology of swine influenza h1n1 flu dr sampurna roy md. The virus replicates in cells of both the upper and lower respiratory tract. The objective of this study is to investigate the pathogenesis of swine influenza virus siv subtype h1n1 and h3n2 thai isolates in 22dayold spf pigs.
Pathogenesis of swine influenza virus subtype h1n2. The increased risk was approximately 1 additional case of gbs per 100,000 people who received swine flu vaccine. Pathogenesis of influenza a virus infection in swine a perfect antigenic match is ideal because it will result in little to no virus replicationdamage, shedding or clinical signs. Swine influenza the center for food security and public health. The 2009 influenza pandemic was a recombinant influenza involving a mix of swine, avian, and human gene segments see h1n1 influenza swine flu. People who work with pigs, especially people with intense exposures, are at increased risk of catching swine flu. It originated in pigs but is spread primarily from person. The 2009 flu pandemic or swine flu was an influenza pandemic that lasted from early 2009 to late 2010, and the second of the two pandemics involving h1n1 influenza virus the first of them being the 19181920 spanish flu pandemic, albeit in a new version. Field isolates of variable virulence exist, and clinical manifestation may be determined by secondary organisms. Fifteen colostrumdeprived pigs aged 3 weeks were inoculated intranasally with virus. Pathogenesis of african swine fever in domestic pigs and european wild boar.
Pdf pathogenesis of swine influenza virus thai isolates in. Cdc since 2005 recommends annual flu vaccination of all infants and children older than 6 months. Swine influenza virus siv or swineorigin influenza virus soiv is any strain of the influenza family of viruses that is endemic in pigs. Several virulence factors have been identified in these virus strains, but host factors are also responsible for the pathogenesis of infections caused by virulent viruses. Hence, although the swine lineage was a direct descendent of the pandemic virus, the post1918 seasonal h1n1 lineage evidently was not, at least for ha. Most sections are based on the nature of the etiologic agent, and all are preceded by their own table of contents. Recent reports of mild to severe influenzalike illness in humans caused by a novel swineorigin 2009 ah1n1 influenza virus underscore the need to better understand the pathogenesis and transmission of these viruses in mammals. Illness with influenza in pigs was first recognized during the influenza pandemic of 1918 to 1919, and a swine influenza virus was first isolated from a human in 1974. 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. Apart from cough, fever, sore throat bird flu patients suffer from eye infections, pneumonia, and other severe problems. During the spring of 2009, a novel influenza a h1n1 virus of swine origin caused human infection and acute respiratory illness in mexico. The purpose of this study was to elucidate pathogenesis and viral distribution in pigs infected with swine influenza virus subtype h1n2, over a period of 10 days, by morphometric analysis and in. Clinical aspects of pandemic 2009 influenza a h1n1 virus. The complete story of the discovery and reconstruction of the 1918 pandemic virus.
The term avian influenza, in this context, refers to zoonotic human infection with an influenza strain that primarily affects birds. H9n2 viruses and asian lineage h5n1 highly pathogenic avian. T he most recent isolated influenza viruses from pigs have been h1n1 viruses swine flu viruses cause high levels of illness and low death rates in pigs. H1n1 swine flu is an acute disease that infects the upper respiratory tract and can cause inflammation of the. Swine influenza virus infection follows the typical pattern for respiratory viral infections. Influenza viruses that commonly circulate in swine are called swine influenza viruses or swine flu viruses. Pinkbook influenza epidemiology of vaccine preventable.
Teifke 1, angele breithaupt 1, christina maresch 1, elke starick 2, sasan fereidouni 2, bernd hoffmann 2, thomas c. The causative agent is known as a type a orthomyxovirus with a segmented rna genome. The study found that all pigs in the infected groups developed typical signs of flulike symptoms on 14 days post infection dpi. Pathogenesis of swine influenza virus thai isolates in.
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