Avian Flu.ppt

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1、Avian Flu,Yurij Kobasa & Ambrish Patel,Overview,1. Background Information2. Brief overview of genome structure 3. Origin/History 4. Geographical Distribution 5. Pandemic Nature 6. Diseases Caused 7. Treatment & Vaccines,Background Information,Envelope with surface proteins, a matrix protein, a nucle

2、oprotein complex, a nucleocapsid, and a polymerase complex; can be spherical or filamentous,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 al

3、lows the influenza virus to bind to cells; it is the major virulence factor for influenza. Neuraminidase is a receptor destroying enzyme, also called sialidase.,Background Information,There are 16 different HA proteins and 9 different NA proteins All known subtypes of flu A viruses can be found in b

4、irds; usually dont 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.,Genomic Structure,Segmented 8 linear, negative sensed, ssRNA segments, totaling for

5、 10-14Kb 5 and 3 terminal repeats of 11-14bp. Each segment has its own nucleocapsid, all nucleocapsids are surrounded by one envelope.,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

6、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 c

7、hickens were culled.,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 vi

8、rus 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.,Geographical Distribution,August 2005 - Kazakhstan, Mongolia, western Russia report outbreaks of H5N1 in poultry China

9、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% earths population) Octobe

10、r 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

11、 see if it is H5N1,Geographical Distribution,Geographical Spread,Geographical Spread,Migratory Bird Patterns,Geographical Spread,Movie Time!,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, an

12、d 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,Pandemic Nature,In 2002, acquired charact

13、eristics 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.,Symptoms,Normal flu symptoms such as

14、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 al

15、so associated with avian flu.,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

16、for H5N1 and H9N2,New Technology,References,http:/ http:/en.wikipedia.org/wiki/H5N1 http:/ http:/www.nlm.nih.gov/medlineplus/birdflu.html http:/www.cdc.gov/flu/avian/ http:/pandemicflu.gov/news/press.html http:/ http:/www.nigms.nih.gov/News/Results/08032005.htm http:/www3.niaid.nih.gov/news/newsrele

17、ases/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:/ http:/www.upc-online.org/spring04/images/image598412x.jpg Nature: Vol 435|26 May 2005,Questions?,