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Avian Influenza – What does it all mean?

Avian Influenza – What does it all mean?. Important Background Information Island Paravets and Residents. Avian Influenza: Background. Waterbirds are the natural reservoir of all Influenza “A” viruses. Wild birds and these diseases have evolved together naturally over time

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Avian Influenza – What does it all mean?

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  1. Avian Influenza –What does it all mean? Important Background Information Island Paravets and Residents

  2. Avian Influenza:Background • Waterbirds are the natural reservoir of all Influenza “A” viruses. Wild birds and these diseases have evolved together naturally over time • Many subtypes of AI already exist in wild bird populations in North America – but currently not HPAI H5N1

  3. Avian Influenza:Background Influenza strains are named for their specific types of protein spikes that act as a “lock and key” mechanism with host cells H = hemagglutinin (16 types) N = neuraminidase (9 types) H5N1 is one of the 144 possible combinations. One subtype (HPAI H5N1) is of concern worldwide. Source: Horimoto and Kawaoka, 2005.

  4. Avian Influenza:Background • Pathogenicity refers to the ability of the virus to produce disease and is based on the impacts to domestic poultry • Low pathogenic = few clinical signs, mostly respiratory and digestive problems • High pathogenic = attack many organs, can cause high mortality • HPAI = kills >75% of chickens • AI viruses can become very pathogenic when they enter a new host (domestic poultry, humans, some carnivores). This is the suspected origin of HPAI strains.

  5. Avian Influenza:Background Significant Variation within current HPAI H5N1 subtypes • Juvenile mallards were inoculated with 23 different isolates of HPAI H5N1 • Results ranged from no clinical signs (n=8 virus isolates) to high lethality in inoculated ducklings • 22/23 virus isolates were efficiently transmitted from inoculated ducklings to susceptible contacts Sturm-Ramirez et al. 2005

  6. Avian Influenza:Background Why are we so worried about “bird flu”? • HPAI H5N1 is spreading rapidly across the globe • HPAI H5N1 has killed 132 out of 230 people infected (57%) • If avian influenza combines genetically with human influenza it can become very infectious among humans • The risk of H5N1 changing to become global pandemic influenza is unknown

  7. Avian Influenza:Background

  8. Avian Influenza:Current Situation HPAI H5N1 Human cases Dec. 2003 to May 2006 CountryCasesDeathsPopulation Indonesia 32 24 207 million Thailand 22 14 65 million Vietnam 9342 84 million 147 80 356 million Average = 1 case per 2.4 million people Average = 1 death per 4.5 million people

  9. Avian Influenza:Current Situation Compared to 230 human cases of HPAI H5N1 worldwide in nearly a decade….. Each year in the U.S. 5-20% of the population will get HUMAN seasonal flu • > 200,000 people hospitalized • ~ 36,000 people die

  10. Avian Influenza:Current Situation Almost all human infections have resulted from direct contact w/ live or dead domestic poultry

  11. Avian Influenza:Current Situation How could HPAI H5N1 reach islands ? Infected People Commercial /Illegal Trade of Birds, Poultry Meat, Eggs Wild Birds

  12. Efforts to “stamp out” HPAI H5N1 in Asia and Europe proving to be difficult • Culling infected flocks • Quarantine infected areas • Enclosing poultry operations • Vaccinating birds

  13. Reporting mortalities -> Culling -> Loss of income unless governments compensate farmers for culled poultry Compensation for flocks is essential for accurate reporting Sale or slaughter of sick birds is known to spread HPAI in Asia Avian Influenza:What You Should Know

  14. Avian Influenza:What is Your Role? • Be “eyes and ears” of animal health authorities • Keep informed about AI via the internet • Become connected with those on- and off-island who will make decisions about responding to HPAI • Know how to respond appropriately • Communicate effectively with the public and government about risks and realities of HPAI H5N1

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