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Avian Flu

Avian Flu. Yurij Kobasa & Ambrish Patel. Overview. 1. Background Information 2. Brief overview of genome structure 3. Origin/History 4. Geographical Distribution 5. Pandemic Nature 6. Diseases Caused 7. Treatment & Vaccines . Background Information.

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Avian Flu

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  1. Avian Flu Yurij Kobasa & Ambrish Patel

  2. Overview 1. Background Information 2. Brief overview of genome structure 3. Origin/History4. Geographical Distribution 5. Pandemic Nature 6. Diseases Caused7. Treatment & Vaccines

  3. Background Information • Envelope with surface proteins, a matrix protein, a nucleoprotein complex, a nucleocapsid, and a polymerase complex; can be spherical or filamentous

  4. Background Information • There are many different subtypes of type A influenza viruses, classified by their different surface proteins, Hemagglutinin [HA] and Neuraminidase [NA] • Hemagluttinin is the protein that allows the influenza virus to bind to cells; it is the major virulence factor for influenza. • Neuraminidase is a receptor destroying enzyme, also called sialidase.

  5. Background Information • There are 16 different HA proteins and 9 different NA proteins • All known subtypes of flu A viruses can be found in birds; usually don’t infect humans • There are only three known A subtypes of human flu viruses (H1N1, H1N2, and H3N2) • Influenza A viruses are constantly mutating and adapting over time to infect and spread among humans.

  6. Genomic Structure • Segmented • 8 linear, negative sensed, ssRNA segments, totaling for 10-14Kb • 5' and 3' terminal repeats of 11-14bp. • Each segment has its own nucleocapsid, all nucleocapsids are surrounded by one envelope.

  7. Origin/History • First H5N1 known crossover from birds to humans was in 1997 in Hong Kong - 18 people were infected and 6 died • In January of 2004 an outbreak occurred in poultry farms in Vietnam @ Thailand, and within weeks it spread to over 10 surrounding countries in Asia (including China, South Korea, Indonesia, Japan). • In February it was isolated in pigs, raising fears of new variant strains. It was contained by March, after 23 people died and over 40 million chickens were culled.

  8. Origin/History • Human to human transmission has been documented in Vietnam and Thailand, but only familial, or to nurses caring for these patients. • When the virus first infected humans the mortality rate was ~65%. • Since then it has gone down to ~35%. • This might indicate that the virus is now able to infect more people and spread more quickly through the population, and becoming a global pandemic with a very high number of deaths despite a low mortality rate.

  9. Geographical Distribution • August 2005 - Kazakhstan, Mongolia, western Russia report outbreaks of H5N1 in poultry • China reported over 1000 migratory birds were found dead, meaning it could now spread into Africa and the Middle East. • September 2005 - UN Health representative David Nabarro announced that a global pandemic could occur at any time, killing between 5 and 150 million people. (2-3% earth's population) • October 2005 - Dead ducks test positive in Romania - 6000 birds culled • Dead turkeys test positive in Turkey and Greece - 5000 birds culled. • A fresh outbreak in Mongolia - 2600 birds tested positive. • Dead swans in Croatia test positive. • October 31st - An H5 strain was found in Canada, still being tested to see if it is H5N1

  10. Geographical Distribution

  11. Geographical Spread

  12. Geographical Spread Migratory Bird Patterns

  13. Geographical Spread Movie Time!

  14. Control of Spread • In 1997, the government of Hong Kong destroyed its entire poultry population, 1.5 million birds. • Hong Kong has banned sale of duck, geese, and quail • Instituted bimonthly cleaning days and vaccination of all locally raised and imported poultry • Thailand limiting poultry movement and destroying infected birds • China and Indonesia using poultry vaccines and Vietnam has started testing poultry vaccines

  15. Pandemic Nature • In 2002, acquired characteristics that allowed it to kill its natural host, the waterfowl • H5N1 expanded host range to tigers, leopards and domestic cats • Recent Finding in Pigs • Two components of pandemic strain: (1)New recombinant strain is formed (2) Easily transmissible amongst humans.

  16. Symptoms • Normal flu symptoms such as high fever, headache, extreme tiredness, dry cough, sore throat, runny or stuff nose, muscle aches, nausea, vomiting, diarrhea, and other stomach symptoms. • Eye infections, pneumonia, severe respiratory diseases such as acute respiratory distress, and other severe and life-threatening symptoms are also associated with avian flu.

  17. Treatment & Vaccines • Currently available Tamiflu® (oseltamavir) and Relenza® (zanamavir), developed resistance to Symmetral® (amantadine) and Flumadine® (rimantadine). • Vaccines available for poultry however no vaccine for human use • Countries working on developing a vaccine for H5N1 and H9N2

  18. New Technology

  19. References • http://www.voanews.com/english/2005-09-30-voa63.cfm • http://en.wikipedia.org/wiki/H5N1 • http://www.reference.com/browse/wiki/Avian_influenza • http://www.nlm.nih.gov/medlineplus/birdflu.html • http://www.cdc.gov/flu/avian/ • http://pandemicflu.gov/news/press.html • http://www.cnn.com/interactive/world/0511/ap.migratory.patterns/frameset.exclude.html • http://www.nigms.nih.gov/News/Results/08032005.htm • http://www3.niaid.nih.gov/news/newsreleases/2005/H5N1QandA.htm • http://www.who.int/csr/disease/influenza/pandemic/en/index.html • http://www.vnn.vn/dataimages/original/images112355_flucoding.jpg • http://www3.niaid.nih.gov/news/focuson/flu/research/prevention/kawaoka_reversegenetics.htm • http://www.scidev.net/News/index.cfm?fuseaction=readNews&itemid=1627&language=1 • http://www.upc-online.org/spring04/images/image598412x.jpg • Nature: Vol 435|26 May 2005

  20. Questions?

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