Avian influenza virus and transmission

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Avian influenza virus and transmission

  1. 1. Avian Influenza Viruses and its role in inter-species Transmission Rokshana Parvin and T.W. VahlenkampINSTITUT FÜR VIROLOGIE
  2. 2. Influenza virus Influenza viruses causes highly contagious respiratory disease with potentially fatal outcomes. Family: Orthomyxoviridae Three main types  Type A Multiple species  Type B Humans  Type C Humans and swine http://www.uct.ac.za/depts/mmi/stannard/fluvirus.htmlINSTITUT FÜR VIROLOGIE
  3. 3. Influenza virus genome The influenza A genome consists of eight single-stranded negative- sense RNA molecules encoded 10 proteins within viral envelope HA - hemagglutinin NA - neuraminidase HA NA M helical nucleocapsid (RNA plus NS NP protein) NP PA lipid bilayer membrane PB1 PB2 polymerase complex M1 proteinINSTITUT FÜR VIROLOGIE
  4. 4. Influenza virus Type A  Influenza A viruses are further classified into subtypes based on the antigenicity of their surface glycoproteins (HA & NA ) Hemagglutinin (HA) Neuraminidase (NA) H1, H2, H3, H4, H5, H6, H7, H8, N1, N2, N3, N4, N5, N6, N7, N8, H9, H10, H11, H12, H13, H14, N9 H15, H16 So far at least 84 serotypes (HA &NA combination) are found in resivour  Infect multiple species Humans Birds (wild birds, domestic poultry) Other animals: pigs, horses, dogs, marine mammals (seals, whales)INSTITUT FÜR VIROLOGIE
  5. 5. H5 H5, H7, H9 H3, H7 HA 1-16 NA 1-9 H4, H7, H13 H1 - H3 H1 - H3 H3, H7 H5, H7, H9 H5INSTITUT FÜR VIROLOGIE
  6. 6. How they transmitted ?????????????? The virus is contracted through  Contact with saliva, nasal secretions and feces of the wild birds.  Contaminated surfaces or materials.  Contaminated water * Direct or indirect contactINSTITUT FÜR VIROLOGIE
  7. 7. True influenza influenza virus A or influenza virus B Febrile respiratory disease with systemic symptoms caused by a variety of other organisms often called „flu‟INSTITUT FÜR VIROLOGIE
  8. 8. Influenza descriptions Influenza name Strain Host affected Outbreak year Seasonal Flu H3, H1 humans yearly Spanish Flu H1N1 humans 1918 Asian Flu H2N2 humans 1957 Hong Kong Flu H3N2 humans 1968, 1970-72 bird flu H5N1 Poultry, 1997, (endemic in 2003……….. avian), human, & cat Swine flu H1N1 Humans, swine 2009 * H1N2 is currently endemic in humans and pigsINSTITUT FÜR VIROLOGIE
  9. 9. Bird Flu: H5N1, H7N7,H9N2…INSTITUT FÜR VIROLOGIE
  10. 10. HPAI LPAI H5, H7 H9, H7 H5N1 H9N2Highly pathogenic viruses result in high Low pathogenicity viruses also causedeath rates (up to 100% mortality within outbreaks in poultry but are not48 hours) in some poultry species generally associated with severe clinical diseaseINSTITUT FÜR VIROLOGIE
  11. 11. transmitted to poultry LPAI virus circulates in Natural reservoir of poultry with mild disease LPAI (H9, H5, H7) virus LPAI Virus Mutates to HPAI with severe diseaseINSTITUT FÜR VIROLOGIE
  12. 12. INSTITUT FÜR VIROLOGIE
  13. 13. • The current outbreaks of highly pathogenic avian influenza, which began in South-East Asia in mid-2003, are the largest and most severe on record • Never before in the history of this disease have so many countries been simultaneously affected, resulting in the loss of so many birdsINSTITUT FÜR VIROLOGIE
  14. 14. Outbreaks map of HPAI H5N1 in poultry (2003 – March 2012) ≥ 100 outbreaks ≥ 10 outbreaks ≥ 1 outbreaksINSTITUT FÜR VIROLOGIE
  15. 15. Bird flu: Why is there a risk for humans? Role of pigs as an intermediate hostINSTITUT FÜR VIROLOGIE
  16. 16. Differences between Pandemics and Epidemics  Pandemics are different from seasonal outbreaks or “epidemics” of influenza  Seasonal outbreaks are caused by subtypes of influenza viruses that are already in existence among people  Pandemic outbreaks are caused by new subtypes or by subtypes that have never circulated among people or that have not circulated among people for a long timeINSTITUT FÜR VIROLOGIE
  17. 17. Seasonal Epidemics vs. Pandemics Seasonal Influenza Influenza Pandemics – A public health problem – Appear in the human each year population rarely and unpredictably – Usually some immunity built up from previous – Human population lacks exposures to the same any immunity subtype – Infants and elderly most – All age groups, including at risk healthy young adultsINSTITUT FÜR VIROLOGIE
  18. 18. If a new subtype of influenza A virus is introduced into the human population, most people have little or no protection against the new virus, and if the virus can spread easily from person to person, a PANDEMIC (worldwide spread) may occurINSTITUT FÜR VIROLOGIE
  19. 19. Prerequisites for pandemic influenza A new influenza virus emerges to which the general population has little/no immunity The new virus must be able to replicate in humans and cause disease The new virus must be efficiently transmitted from one human to another Ingredients for a pandemic are abundantly availableINSTITUT FÜR VIROLOGIE
  20. 20. Influenza A viruses are renowned for their rapid evolution in aberrant hosts including humans Antigenic drift occurs when single Antigenic shift takes place when two nucleotides are replaced over time different viruses infect the same cell and through mutations new viral particles are created with new combinations or assortments of the 8 influenza moleculesINSTITUT FÜR VIROLOGIE
  21. 21. INSTITUT FÜR VIROLOGIE
  22. 22. Antigenic shift Sick Pig with both Strands of InfluenzaINSTITUT FÜR VIROLOGIE
  23. 23. 1st pandemics of 21th century Pandemic Year Influenza virus People infected Estimated deaths type worldwide Swine flu 2009– Pandemic > 622,482 (lab- 14,286 (lab-confirmed; 2010 H1N1 confirmed) ECDC 18,036 (lab- confirmed;WHO) The pandemic that began in March 2009 was caused by an H1N1 influenza A virus that represents a quadruple reassortment of two swine strains, one human strain, and one avian strain of influenza; the largest proportion of genes came from swine influenza viruses.INSTITUT FÜR VIROLOGIE
  24. 24. History of Reassortment Events in the Evolution of Influenza A H1N1/09 H1N1/ 09INSTITUT FÜR VIROLOGIE
  25. 25. INSTITUT FÜR VIROLOGIE
  26. 26. 20th century flu pandemics Spanish flu Asian flu Hong Kong Flu Emergency military hospital Childrens ward during Hong Kong Flu Pandemic during Spanish flu pandemic Asian flu pandemic (1968,1970-1972) (1918) (1957) A(H1N1) A(H2N2) A(H3N2) 20-40 m deaths 1-4 m deaths 1-4 m deathsINSTITUT FÜR VIROLOGIE
  27. 27. INSTITUT FÜR VIROLOGIE
  28. 28. Now literature says… Bird flu can transmitted directly from birds to humansINSTITUT FÜR VIROLOGIE
  29. 29. Possible mechanisms for the generation of pandemic influenza virusesINSTITUT FÜR VIROLOGIE
  30. 30. Current situationINSTITUT FÜR VIROLOGIE
  31. 31. INSTITUT FÜR VIROLOGIE
  32. 32. INSTITUT FÜR VIROLOGIE
  33. 33. http://www.who.int/csr/don/2012_04_12/en/index.htmlINSTITUT FÜR VIROLOGIE
  34. 34. http://www.oie.int/fileadmin/Home/eng/Animal_Health_in_the_World/docs/pdf/gr aph_avian_influenza/graphs_HPAI_31_03_2012.pdfINSTITUT FÜR VIROLOGIE
  35. 35. INSTITUT FÜR VIROLOGIE
  36. 36. http://www.fao.org/ag/againfo/programmes/en/empres/maps_cum_archive.htmlINSTITUT FÜR VIROLOGIE
  37. 37. Next warning ?INSTITUT FÜR VIROLOGIE
  38. 38. INSTITUT FÜR VIROLOGIE
  39. 39. For your kind attention!!!!INSTITUT FÜR VIROLOGIE
  40. 40. INSTITUT FÜR VIROLOGIE
  41. 41. INSTITUT FÜR VIROLOGIE

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