How serious is the threat How serious is the threat of an Avian flu Human of an Avian flu Human

PandemicPandemicAvian (Bird)Avian (Bird)

December 2005December 2005

Avian Flu Avian Flu

VirusVirus BacteriaBacteria Infection Infection MutationMutation

Carrier of infectionCarrier of infection Resistance to Resistance to

infectioninfection Spread of infectionSpread of infection Genetic materialGenetic material

General Background Terms

Avian FluAvian FluHistorical DevelopmentHistorical Development

Influenza Virus (worldwide problem)Influenza Virus (worldwide problem) Types A-B-CTypes A-B-C ““HN” Classification of virus (lab testing)HN” Classification of virus (lab testing)

HemagglutininHemagglutinin NeuraminidaseNeuraminidase

1918 “Spanish” Flu (H1918 “Spanish” Flu (H11NN11)) Killed 50 million people worldwideKilled 50 million people worldwide

1961 H 1961 H 55 NN11 found in wild birds in South Africa found in wild birds in South Africa

1997 H1997 H55NN11 found in Hong Kong found in Hong Kong

2003 Bird Flu re-emergence in South Asia2003 Bird Flu re-emergence in South Asia

Avian FluAvian Flu

Mechanism of Non-Human SpreadMechanism of Non-Human Spread Once spread from wild bird population to domestic Once spread from wild bird population to domestic

birds (Chickens): a first serious step has occurredbirds (Chickens): a first serious step has occurred

A viral “jump” to more domestic animals (horses, A viral “jump” to more domestic animals (horses, cats, pigs): a second serious step will have cats, pigs): a second serious step will have occurredoccurred

This broad “mixing pot” of genetic material; This broad “mixing pot” of genetic material; makes the spread to humans more likely from makes the spread to humans more likely from such a pool of replicating gene fragmentssuch a pool of replicating gene fragments

Avian FluAvian FluIsolated FactsIsolated Facts New HNew H55NN11 virus comes from mostly avian gene pool (not virus comes from mostly avian gene pool (not mammals) like the Hmammals) like the H11NN11 Spanish flu did (1918) Spanish flu did (1918)

Why has it now become lethal in some humans? Unknown!Why has it now become lethal in some humans? Unknown! HH55NN11 virus remain “alive” in feces, oral droppings, virus remain “alive” in feces, oral droppings,

contaminated water for 7-10 dayscontaminated water for 7-10 days Asian human HAsian human H55NN11 infections are in younger population infections are in younger population

(17-31yrs)(17-31yrs) In south Asia, human infection has mostly involved In south Asia, human infection has mostly involved

direct, close contact with infected birds (blood, feces, direct, close contact with infected birds (blood, feces, feathers)feathers)

Avian FluAvian Flu

Isolated Facts Cont’dIsolated Facts Cont’d

Current human Influenza A vaccine does not protect against HCurrent human Influenza A vaccine does not protect against H55NN11 Flu; eating “cooked” infected chickens will not cause infectionFlu; eating “cooked” infected chickens will not cause infection

Domestic ducks can carry HDomestic ducks can carry H55NN1 1 “silently”: so a reservoir for “silently”: so a reservoir for potential carrier of infectionpotential carrier of infection

Domestic chickens get “infected” from contact with shed Domestic chickens get “infected” from contact with shed droppings from “migratory waterfowl/ducks”droppings from “migratory waterfowl/ducks”

The HThe H55NN11 avian flu is 32 times more avian flu is 32 times more infective than SARS Virus (2003)infective than SARS Virus (2003)

Avian FluAvian Flu

Human Pandemic Requires:Human Pandemic Requires:

Highly virulent organismHighly virulent organism

Lack of sufficient human immunity Lack of sufficient human immunity

Easy spread from human to human Easy spread from human to human

This is currently absentThis is currently absent

Avian FluAvian Flu

Potential Catastrophic ChangePotential Catastrophic Change

H H 55 N N11 Virus Virus Invades Human Cell Invades Human Cell

ReplicatesReplicates

Organ Damage Organ Damage Invades Other Cells Invades Other Cells Lung Lung

Heart Heart Kidney Kidney

“Mutates”

Avian FluAvian Flu

Human DiagnosisHuman Diagnosis Spot testingSpot testing Local LabsLocal Labs Reference Labs (CDC)Reference Labs (CDC) Physicians/HospitalsPhysicians/Hospitals

Avian FluAvian Flu

InitialInitial High feverHigh fever Chest painChest pain CoughCough Weakness, muscle Weakness, muscle

achesaches Easy bleedingEasy bleeding DiarrheaDiarrhea

LateLate PneumoniaPneumonia EncephalitisEncephalitis Kidney failureKidney failure

Human signs and Symptoms

Currently in East Asia : mortality 50 %

(n=150 cases)

Avian FluAvian Flu

Current Spread of Avian Disease (Asia to Current Spread of Avian Disease (Asia to Europe)Europe)

North to Mongolia/Siberia North to Mongolia/Siberia

East AsiaEast Asia

West to Ukraine, Croatia, West to Ukraine, Croatia, TurkeyTurkey

Avian FluAvian FluTreatmentTreatmentSurveillanceSurveillance

China may be Ground Zero (1China may be Ground Zero (1stst line of defense) line of defense) 1.3 billion people1.3 billion people 13 billion birds13 billion birds 75% of population live on farms75% of population live on farms Medical system weakMedical system weak

Prophylaxis (For Chickens)Prophylaxis (For Chickens) Twice a year vaccinesTwice a year vaccines

Bird Flu Outbreak Bird Flu Outbreak Authorities kill hundreds of thousands of birdsAuthorities kill hundreds of thousands of birds

Avian FluAvian Flu

Human Treatment Human Treatment QuarantineQuarantine

World health Organization (WHO)World health Organization (WHO) 21 days to “control”21 days to “control”

Before disease affects 20-30 peopleBefore disease affects 20-30 people Hard for doctor to diagnosis Hard for doctor to diagnosis

quickly/implement isolation quickly/implement isolation Area may be as large as a city Area may be as large as a city

Avian FluAvian FluHuman Treatment Human Treatment

VaccineVaccine Available for bird nowAvailable for bird now In development for humanIn development for human Problems with applicationProblems with application

New mutation may limit effectivenessNew mutation may limit effectiveness

AntiviralsAntivirals Tamiflu (oral)Tamiflu (oral) Relenza (inhalation)Relenza (inhalation) Problems with application of these medsProblems with application of these meds

Not thoroughly testedNot thoroughly tested Resistance occursResistance occurs Stockpilling can be disruptiveStockpilling can be disruptive

Avian FluAvian FluPossible Global Possible Global Threat Threat (Worst case scenario)(Worst case scenario)

Estimate 150 million human deaths Estimate 150 million human deaths worldwide worldwide

Estimate economic cost : 800 billion dollarsEstimate economic cost : 800 billion dollars Theoretical terrorist operation:Theoretical terrorist operation:

steal deadly viral genomesteal deadly viral genome

harvest “live” virus in labharvest “live” virus in lab

deliver as aerosol to unsuspecting populacedeliver as aerosol to unsuspecting populace

Avian FluAvian Flu

Conclusions Conclusions Far-reaching spread of deadly virus to USA Far-reaching spread of deadly virus to USA

(Unlikely) (Unlikely) Danger ofDanger of HH55NN11 reaching USA is realreaching USA is real

Interconnected world (infection carriers)Interconnected world (infection carriers) Wild birds (could first reach Alaska & Canada)Wild birds (could first reach Alaska & Canada) Human travelers (a flight away)Human travelers (a flight away)

No intervention has been successful No intervention has been successful stopping a pandemic once it startsstopping a pandemic once it starts

Avian FluAvian FluConclusionsConclusions Surveillance, global cooperation, vaccination, Surveillance, global cooperation, vaccination,

antiviral agents,quarantine, infected chicken antiviral agents,quarantine, infected chicken elimination will prevent epidemic spread in USAelimination will prevent epidemic spread in USA

Gene Mutation and Viral human to human Gene Mutation and Viral human to human spread is random and cannot be controlledspread is random and cannot be controlled

SOSO

viral illnesses are a stark reality we have to viral illnesses are a stark reality we have to fightfight