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How serious is the threat of an Avian flu Human Pandemic

How serious is the threat of an Avian flu Human Pandemic . Avian (Bird) December 2005. Virus Bacteria Infection Mutation. Carrier of infection Resistance to infection Spread of infection Genetic material. Avian Flu . General Background Terms . Avian Flu. Historical Development

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How serious is the threat of an Avian flu Human Pandemic

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  1. How serious is the threat of an Avian flu Human Pandemic Avian (Bird) December 2005

  2. Virus Bacteria Infection Mutation Carrier of infection Resistance to infection Spread of infection Genetic material Avian Flu General Background Terms

  3. Avian Flu Historical Development Influenza Virus (worldwide problem) Types A-B-C • “HN” Classification of virus (lab testing) • Hemagglutinin • Neuraminidase • 1918 “Spanish” Flu (H1N1) • Killed 50 million people worldwide • 1961 H 5N1 found in wild birds in South Africa • 1997 H5N1 found in Hong Kong • 2003 Bird Flu re-emergence in South Asia

  4. Avian Flu Mechanism of Non-Human Spread • Once spread from wild bird population to domestic birds (Chickens): a first serious step has occurred • A viral “jump” to more domestic animals (horses, cats, pigs): a second serious step will have occurred • This broad “mixing pot” of genetic material; makes the spread to humans more likely from such a pool of replicating gene fragments

  5. Avian Flu Isolated Facts New H5N1 virus comes from mostly avian gene pool (not mammals) like the H1N1 Spanish flu did (1918) • Why has it now become lethal in some humans? Unknown! • H5N1 virus remain “alive” in feces, oral droppings, contaminated water for 7-10 days • Asian human H5N1 infections are in younger population (17-31yrs) • In south Asia, human infection has mostly involved direct, close contact with infected birds (blood, feces, feathers)

  6. Avian Flu Isolated Facts Cont’d • Current human Influenza A vaccine does not protect against H5N1 Flu; eating “cooked” infected chickens will not cause infection • Domestic ducks can carry H5N1 “silently”: so a reservoir for potential carrier of infection • Domestic chickens get “infected” from contact with shed droppings from “migratory waterfowl/ducks” The H5N1 avian flu is 32 times more infective than SARS Virus (2003)

  7. Avian Flu Human Pandemic Requires: • Highly virulent organism • Lack of sufficient human immunity • Easy spread from human to human This is currently absent

  8. Avian Flu Potential Catastrophic Change H 5 N1 Virus Invades Human Cell Replicates Organ Damage Invades Other Cells Lung Heart Kidney “Mutates”

  9. Avian Flu Human Diagnosis • Spot testing • Local Labs • Reference Labs (CDC) • Physicians/Hospitals

  10. Initial High fever Chest pain Cough Weakness, muscle aches Easy bleeding Diarrhea Late Pneumonia Encephalitis Kidney failure Avian Flu Human signs and Symptoms Currently in East Asia : mortality 50 % (n=150 cases)

  11. Avian Flu Current Spread of Avian Disease (Asia to Europe) North to Mongolia/Siberia East Asia West to Ukraine, Croatia, Turkey

  12. Avian Flu Treatment Surveillance • China may be Ground Zero (1st line of defense) • 1.3 billion people • 13 billion birds • 75% of population live on farms • Medical system weak • Prophylaxis (For Chickens) • Twice a year vaccines • Bird Flu Outbreak • Authorities kill hundreds of thousands of birds

  13. Avian Flu Human Treatment Quarantine • World health Organization (WHO) • 21 days to “control” • Before disease affects 20-30 people • Hard for doctor to diagnosis quickly/implement isolation • Area may be as large as a city

  14. Avian Flu Human Treatment • Vaccine • Available for bird now • In development for human • Problems with application • New mutation may limit effectiveness • Antivirals • Tamiflu (oral) • Relenza (inhalation) • Problems with application of these meds • Not thoroughly tested • Resistance occurs • Stockpilling can be disruptive

  15. Avian Flu Possible Global Threat (Worst case scenario) • Estimate 150 million human deaths worldwide • Estimate economic cost : 800 billion dollars • Theoretical terrorist operation: steal deadly viral genome harvest “live” virus in lab deliver as aerosol to unsuspecting populace

  16. Avian Flu Conclusions • Far-reaching spread of deadly virus to USA (Unlikely) • Danger ofH5N1reaching USA is real • Interconnected world (infection carriers) Wild birds (could first reach Alaska & Canada) Human travelers (a flight away) No intervention has been successful stopping a pandemic once it starts

  17. Avian Flu Conclusions • Surveillance, global cooperation, vaccination, antiviral agents,quarantine, infected chicken elimination will prevent epidemic spread in USA • Gene Mutation and Viral human to human spread is random and cannot be controlled SO viral illnesses are a stark reality we have to fight

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