Ppt on swine influenza snehdeep

Ppt on swine influenza snehdeep

• 1.
  Dr. Snehdeep Patil
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  The Biggest InfectiousDisease Events of the 20th Century • Pandemic flu (1918 – 1919,1957,1968) • Discovery of Penicillin • Eradication of Smallpox • Emergence of HIV/AIDS • The emergence of the bioterrorism threat for e.g. The anthrax letters.
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  The Early Historyof Influenza • 2500 BC - domestication of ducks, bringing influenza close to human beings • 412 BC - Hippocrates describes a disease that is probably influenza • 1580 - 1st recorded pandemic: an outbreak in Europe & parts of Africa & Asia • 1889 - Unknown influenza subtype (probably Russian flu) begins in Central Asia & spreads to Russia and other parts of world.
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  Influenza in the20th Century • 1918 - Spanish flu H1N1 (swine flu) killed 20-40 million people worldwide, more than on the battlefields of WWI • 1930 - H1N1 first isolated • 1957 - Asian flu H2N2 pandemic started in China and killed 70,000 in the US • 1968 - Hong Kong H3N2 pandemic killed 34,000 in the US • 1976 - Swine flu scare (only 1 death)
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  Major Pandemic :Historical Clues 1918: ‘Spanish’ Flu Major pandemic: 20-40 million deaths worldwide Attacked mainly young & healthy adults: rapid death from respiratory failure Several waves: next older patients Clinical attack rate: 25-40% Case fatality rate: 2-4%
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  Minor Pandemic: HistoricalClues 1957: Asian Flu February: New strain H2N2 identified. Little prior immunity. Reassortant mutation (avian/human). Minor pandemic May: Vaccine production begins. June: Hits U.S. border quietly. September: “Back to school” outbreak, highest mortality. February 1958: “Second wave” amongst elderly. -Clinical attack rate: 25% -Case fatality rate: 0.2% -Total mortality: 70,000 in US, 1 million worldwide
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  Minor Pandemic: HistoricalClues 1968: Hong Kong Flu H3N2 strain: thought reassortant Attacked mainly population over age 65 Clinical attack rate: 20-25% Case fatality rate: 0.1% Mortality: 35,000 US, < 1 million in world
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  There is aflu pandemic abouT once every generaTion; The lasT being 1968. So we are overdue!
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  Influenza virus • Rootscome for “Influenza” from following languages:  In Latin influenza means ‘Virus’.  In Italian influenza means ‘Infection’. • First seen as poisons, then life forms, then biological chemicals • Now known to be an RNA virus • Like many other viruses now thought of as a grey area between the living and the non-living.
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  Orthomyxoviruses • Influenza A,B & C. • Enveloped and Pleomorphic • 8 gene segments code for 10 proteins • Single-stranded RNA viruses (13.6 kB) • RNA exhibits high mutation rates
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  The Influenza AVirus • RNA, enveloped • Viral family: Orthomyxoviridae • Size: 80-200nm or .08 – 0.12 μm (micron) in diameter • Three types • A, B, C • Surface antigens • H (haemaglutinin) • N (neuraminidase)
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  Influenza: Molecular origins InfluenzaA & B 2 major surface glycoproteins Hemagglutinin (HA) -16 subtypes—H1, H2, H3: capable of widespread human respiratory infection -Site of attachment to host cells -Antibody confers protection against disease Neuraminidase (NA) -9 subtypes -Aids in release of virions from cells -Antibody can help modify disease severity
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  Human Pathogenesis • Invadesrespiratory epithelium with highly toxic viral particles • Impairs mechanical and cellular host responses • Elicits acute inflammatory response – Leads to ciliary abnormalities – Desquamation of ciliated and mucus-producing cells. • Loss of mechanical clearance of respiratory tract (no escalator) • Normal respiratory epithelium restored 2 - 10 weeks after infection • Damage renders host susceptible to invasive bacterial superinfections • Virus in blood is detected rarely
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  EPIDEMIOLOGY: Influenza A circulatesin three major pools of animals. • In humans, infection spread by respiratory-droplet route. • In wild birds, infection spread by fecaloral route. • In farm animals, infection spread by both routes – Swine (respiratory-droplet) – Chickens and ducks (fecal-oral)
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  Influenza: Molecular origins Antigenicdrift Antigenic shift - Continuous evolving process modifications in viral HA or NA new strain variants reinfect people throughout life yearly updated flu vaccine - Small drift: outbreaks (yearly) - Large drift: epidemics (every few years) - Sudden, major change in combinations of HA and/or NA proteins on virus surface new influenza A virus to which there is no pre-existing immunity - Small shift: minor pandemic (every 30-50 years) - Large shift: major pandemic (every 100 years)
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  Influenza A Epidemics Pandemics •In "epidemic" years, 10% -20% of world’s population gets influenza. • Associated with 500,000 to 1,000,000 deaths worldwide. • Caused by genetic “drifts” • Point mutations in gene segments: H1 ---> H1 • In "pandemic" years, worldwide population gets influenza. • Associated with a disproportionate number of deaths worldwide. • Caused by genetic “shifts” • Complete substitutions of gene segments: H1 ---> H5
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  Swine Influenza (Flu) SwineInfluenza (swine flu) is a respiratory disease of pigs caused by type A influenza that regularly cause outbreaks of influenza among pigs. SIV strains isolated to date have been classified either as Influenza(virus C or one of the various subtypes of the genus Influenza virus A). Swine flu viruses do not normally infect humans.  However, human infections with swine flu do occur, and cases of human-to-human spread of swine flu viruses has been documented.
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  Swine Influenza (Flu) Swineflu viruses cause high levels of illness and low death rates in pigs. It may circulate among swine(pig) throughout the year, but most outbreaks occur during the late fall and winter months similar to outbreaks in humans. The classical swine flu virus (an influenza type A H1N1 virus) was first isolated from a pig in 1930.
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  Different Strains circulatePeriodically In the United States the H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. As of 2004, H3N2 virus isolates in US swine and turkey stocks were triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages.
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  Swine Flu differsfrom Human Flu The H1N1 swine flu viruses are antigenically very different from human H1N1 viruses and, therefore, vaccines for human seasonal flu would not provide protection from H1N1 swine flu viruses
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  Present Swine Flustrains At this time, there are four main influenza type A virus subtypes that have been isolated in pigs: H1N1, H1N2, H3N2, and H3N1. However, most of the recently isolated influenza viruses from pigs have been H1N1 viruses.
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  How Swine fluspread among Pigs ? Swine flu viruses are thought to be spread mostly through close contact among pigs and possibly from contaminated objects moving between infected and uninfected pigs. Herds with continuous swine flu infections and herds that are vaccinated against swine flu may have sporadic disease, or may show only mild or no symptoms of infection.
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  How man isexposed Most commonly, these cases occur in persons with direct exposure to pigs (e.g. children near pigs at a fair or workers in the swine industry). In addition, there have been documented cases of one person spreading swine flu to others.
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  Does eating Porkinfect us? No. Swine influenza viruses are not transmitted by food. You can not get swine influenza from eating pork or pork products. Eating properly handled and cooked pork and pork products is safe. Cooking pork to an internal temperature of 160°F kills the swine flu virus as it does other bacteria and viruses
• 29.
  Close proximity withPIGS spread the Infections Influenza viruses can be directly transmitted from pigs to people and from people to pigs. Human infection with flu viruses from pigs are most likely to occur when people are in close proximity to infected pigs, such as in pig barns and livestock exhibits housing pigs at fairs. Human-to-human transmission of swine flu can also occur.
• 30.
  Swine Flu :IndianScenario 29th May 2009 there is one imported case that came from U.S.A. Lab confirmed cases reported during the Week(From 21st June to 27th June 2010) are 345. Till date, samples from 143285 persons have been tested for Influenza A H1N1 in Government Laboratories and a few private Laboratories across the country and 33083 (23.0%) of them have been found positive. Death of Lab confirmed cases during the Week(From 21st June to 27th June 2010) are 17. Death of Lab confirmed cases cumulative are 1584.
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  Swine Flu :MaharashtraScenario Lab confirmed cases reported during the Week(From 21st June to 27th June 2010) are 36. Lab confirmed cases cumulative 6406. Death of Lab confirmed cases during the Week(From 21st June to 27th June 2010) are 7. Death of Lab confirmed cases cumulative are 483.
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  Pigs can harbourinfluenza viruses can be adapted to Humans