Avian Influenza and the Avian Influenza and the Threat of an Impending Threat of an Impending

PandemicPandemic

Eden V. Wells, MD, MPHEden V. Wells, MD, MPHMichigan Department of Michigan Department of

Community HealthCommunity Health

Influenza StrainsInfluenza StrainsType AType A– Infects animals and humansInfects animals and humans– Moderate to severe illnessModerate to severe illness– Potential epidemics/pandemicsPotential epidemics/pandemics

Type BType B– Infects humans onlyInfects humans only– Milder epidemicsMilder epidemics– Larger proportion of children affectedLarger proportion of children affected

Type CType C– No epidemicsNo epidemics– Rare in humansRare in humans

Source: CDC

A’s and B’s, H’s and N’sA’s and B’s, H’s and N’s

Classified by its RNA coreClassified by its RNA core– Type A or Type B influenzaType A or Type B influenza

Further classified by surface proteinFurther classified by surface protein– Neuraminidase (N) – 9 subtypes knownNeuraminidase (N) – 9 subtypes known– Hemagluttin (H) – 16 subtypes knownHemagluttin (H) – 16 subtypes known

Only Influenza A has pandemic Only Influenza A has pandemic potentialpotential

Influenza Virus StructureInfluenza Virus Structure

A/Moscow/21/99 (H3N2)

Neuraminidase

Hemagglutinin

Type of nuclearmaterial

Virustype

Geographicorigin

Strainnumber

Year of isolation

Virus subtype

Differentiating InfluenzaDifferentiating Influenza SeasonalSeasonal

– Caused by influenza A or B strains circulating in humans Caused by influenza A or B strains circulating in humans – ~36,000 human deaths annually in USA~36,000 human deaths annually in USA

Avian– Caused by Influenza A– Shorebirds and water fowl are the reservoir and rarely see

outbreaks, except in current H5N1 strain– Domestic poultry (chickens and turkeys), causes

morbidity and mortality with outbreaks annually worldwide

Pandemic

– When new virus strain occurs

– Humans lack immunity

– Simultaneous epidemics worldwide

– Disease easily transmitted between people

– Significant number of illness and deaths

Influenza A: Influenza A: Antigenic Drift and ShiftAntigenic Drift and Shift

Hemagglutinin (HA) and neuraminadase Hemagglutinin (HA) and neuraminadase (NA) structures can change(NA) structures can change

DriftDrift: minor point mutations: minor point mutations – associated with seasonal changes/epidemicsassociated with seasonal changes/epidemics– subtype remains the samesubtype remains the same

Shift:Shift: major genetic changes major genetic changes (reassortments)(reassortments)– making a new subtype making a new subtype – can cause pandemiccan cause pandemic

Seasonal InfluenzaSeasonal Influenza

October to AprilOctober to April

People should get flu vaccinePeople should get flu vaccine

Children and elderly most proneChildren and elderly most prone

~36,000 deaths annually in U.S.~36,000 deaths annually in U.S.

Seasonal EffectsSeasonal Effects

Seasonal Influenza SurveillanceSeasonal Influenza Surveillance

Avian InfluenzaAvian InfluenzaThe “Bird Flu”The “Bird Flu”

Images from: http://www.usda.gov/oc/photo

Avian InfluenzaAvian Influenza

Infection can be in two formsInfection can be in two forms– ““low pathogenic” (LPAI) - causes mild illness low pathogenic” (LPAI) - causes mild illness

and may go undetectedand may go undetected

– ““highly pathogenic” (HPAI) - affects multiple highly pathogenic” (HPAI) - affects multiple organs, spreads rapidly among birds, organs, spreads rapidly among birds, causes high mortality very quicklycauses high mortality very quickly

Avian Influenza and Avian Influenza and Domestic PoultryDomestic Poultry

Virus is shed in saliva, nasal secretions, and Virus is shed in saliva, nasal secretions, and feces of infected birdsfeces of infected birds

Virus can survive for long periods in feces, Virus can survive for long periods in feces, water, and even on the ground, especially water, and even on the ground, especially when environmental temperatures are lowwhen environmental temperatures are low

Avian influenza is a Avian influenza is a reportablereportable disease in disease in MichiganMichigan

The Role of Animals in The Role of Animals in Influenza A InfectionInfluenza A Infection

Shore Birds and

Wild Waterfowl

Domestic Birds

Mammals

Humans

Countries with H5N1 in PoultryCountries with H5N1 in Poultry(OIE, 8/22/06)(OIE, 8/22/06)

AfghanistanAfghanistanAlbaniaAlbaniaAzerbaijanAzerbaijanBurkina FasoBurkina FasoCameroonCameroonCambodiaCambodiaChinaChinaCote d’ IvoireCote d’ IvoireCyprusCyprusDenmarkDenmarkDijboutiDijboutiEgyptEgyptFranceFranceGermanyGermany

HungaryHungaryIndiaIndiaIndonesiaIndonesiaIraqIraqIsraelIsraelJapanJapanJordanJordanKazakhstanKazakhstanLaosLaosMalaysiaMalaysiaMyanmarMyanmarNigerNigerNigeriaNigeria

•North Korea•Pakistan•Palestian Aut. Territories•Romania•Russia•Serbia and Montenegro•South Korea•Sudan•Sweden•Thailand•Turkey•Ukraine•Vietnam

Domestic Poultry SurveillanceDomestic Poultry Surveillance

• Michigan veterinarians are responsible for overall livestock and poultry reportable disease programs

• They conduct investigations into reports of diseases such as:

– Avian influenza– Rabies– Eastern equine encephalitis– Equine infectious anemia– Tuberculosis– Psittacosis

www.michigan.gov/MDA

H5N1 in Poultry and Wild BirdsH5N1 in Poultry and Wild Birds(WHO, 8/2/06)(WHO, 8/2/06)

Countries with H5N1 in Wild BirdsCountries with H5N1 in Wild Birds(OIE, 8/22/05)(OIE, 8/22/05)

•Afghanistan

•Austria

•Azerbaijan

•Bosnia and Herzegovina

•Bulgaria

•Cambodia

•Cameroon

•China

•Cote d’ Ivoire

•Croatia

•Czech Republic

•Denmark

•Egypt

•France

•Georgia

•Germany

•Greece

•Hungary

•Indonesia

•Iran

•Italy

•Japan

•Kazakhstan

•Kuwait

•Mongolia

•Nigeria

•Poland

•Russia

•Serbia and Montenegro

•Slovakia

•Slovenia

•South Korea

•Spain

•Sweden

•Switzerland

•Thailand

•Turkey

•Ukraine

•United Kingdom

•Vietnam

• Wildlife biologist monitor diseases of wild birds at the population level

• Sick or Dead Wildlife website reporting

• Bird Banding

• Hunter Surveillance

Wild Bird SurveillanceWild Bird Surveillance

http://www.michigan.gov/dnr

H5N1 Influenza in Humans-H5N1 Influenza in Humans-RiskRisk

Transmission from birds to humans does Transmission from birds to humans does not occur easilynot occur easily– Contact with feces or secretions from infected Contact with feces or secretions from infected

birdsbirds– Risk with butchering, preparing, defeathering Risk with butchering, preparing, defeathering

of infected birdsof infected birds– NOT transmitted through cooked foodNOT transmitted through cooked food

Implications for Human HealthImplications for Human Health

Asian Strain H5N1 in humans more aggressive Asian Strain H5N1 in humans more aggressive than seasonal flu strainsthan seasonal flu strains– Severe clinical courseSevere clinical course– Rapid deteriorationRapid deterioration– High fatalityHigh fatality– Low transmissibility human-to-humanLow transmissibility human-to-human

Incubation may be longer than seasonal influenzaIncubation may be longer than seasonal influenza– Seasonal influenza: 2-3 daysSeasonal influenza: 2-3 days– H5N1: possibly up to 10 daysH5N1: possibly up to 10 days

More studies neededMore studies needed

Confirmed Human Cases of H5N1Confirmed Human Cases of H5N1(WHO, 8/23/06)(WHO, 8/23/06)

CountryCountry H5N1 CasesH5N1 Cases FatalitiesFatalities Mortality Rate (%)Mortality Rate (%)

Azerbaijan 88 55 6363

CambodiaCambodia 66 66 100100

ChinaChina 2121 1414 6767

DjiboutiDjibouti 11 00 00

EgyptEgypt 1414 66 4343

IndonesiaIndonesia 6060 4646 7777

IraqIraq 22 22 100100

ThailandThailand 2424 1616 6767

TurkeyTurkey 1212 44 3333

VietnamVietnam 9393 4242 4545

TotalTotal 241241 141141 5959

http://www.pandemicflu.gov/ (July 7, 2006)

What is the H5N1 Pandemic What is the H5N1 Pandemic Risk?Risk?

Three conditions must be met for a pandemic Three conditions must be met for a pandemic to start:to start:– Emergence of a new influenza subtypeEmergence of a new influenza subtype

– The strain infects humans causing The strain infects humans causing serious illnessserious illness

– Spreads easily between humansSpreads easily between humans

Each new H5N1 human case gives the virus Each new H5N1 human case gives the virus a chance to mutate into a highly a chance to mutate into a highly transmissible form, increasing the risk of a transmissible form, increasing the risk of a pandemicpandemic

MDCH Pandemic Influenza Plan MDCH Pandemic Influenza Plan 20052005

Revision of 2002 planRevision of 2002 plan

Released November 2005Released November 2005

Appendix to MDCH All-Hazards Response Appendix to MDCH All-Hazards Response PlanPlan

Pandemic plan updated as neededPandemic plan updated as needed

www.michigan.gov/influenzawww.michigan.gov/influenza

Leads for Public HealthLeads for Public Health

InternationalInternational: World Health Organization: World Health Organization

United StatesUnited States: Centers for Disease Control : Centers for Disease Control and Prevention, DHHSand Prevention, DHHS

MichiganMichigan: Michigan Department of : Michigan Department of Community HealthCommunity Health

CountyCounty: Local Health Department/Jurisdiction: Local Health Department/Jurisdiction

Current WHO Risk Current WHO Risk AssessmentAssessment

2020thth Century Influenza Century Influenza PandemicsPandemics

1918 – 1919, “Spanish Flu” (H1N1)1918 – 1919, “Spanish Flu” (H1N1)– Influenza A H1N1 viruses still circulate todayInfluenza A H1N1 viruses still circulate today– US mortality: approx. 500,000+ US mortality: approx. 500,000+

1957-58, “Asian Flu” (H2N2)1957-58, “Asian Flu” (H2N2)– Identified in China (February 1957) with spread to Identified in China (February 1957) with spread to

US by JuneUS by June– US mortality: 69,800US mortality: 69,800

1968-69, “Hong Kong Flu” (H3N2)1968-69, “Hong Kong Flu” (H3N2)– Influenza A H3N2 viruses still circulate todayInfluenza A H3N2 viruses still circulate today– First detected in Hong Kong (early 1968) and First detected in Hong Kong (early 1968) and

spread to US later that yearspread to US later that year– US mortality: 33,800US mortality: 33,800

Estimated Impact Estimated Impact of a Future Pandemic in of a Future Pandemic in

MichiganMichigan

(*Michigan figures developed with Flu-Aid 2.0 (*Michigan figures developed with Flu-Aid 2.0 software, CDC)software, CDC)

CharacteristicModerate

(1957 / ‘68-like)Severe

(1918-like)

Illness 3.4 million 3.4 million

Outpatient 2.5 million 1.5 million

Hospitalization 51,000 420,000

Deaths 15,000 125,000

Influenza SurveillanceInfluenza Surveillance

Michigan Disease Michigan Disease Surveillance SystemSurveillance SystemSentinel SurveillanceSentinel SurveillanceSyndromicSyndromic– PharmacyPharmacy– ERER

Laboratory Laboratory National National InternationalInternational

LHD’s/LHD’s/MDSSMDSS

Non-MDCH Non-MDCH LabsLabs

WHO DataWHO Data

CDC DataCDC DataLHD’s/LHD’s/

Healthcare Healthcare providersproviders

PharmacyPharmacy OTCOTC

Sentinel Sentinel PhysiciansPhysicians

ER ER SyndromicSyndromic

HospitalsHospitals

MDCH MDCH LabsLabs

Mi-FluMi-FluFocusFocus

Treatment OptionsTreatment Options

Antiviral MedicationsAntiviral Medications– Neuraminidase InhibitorsNeuraminidase Inhibitors

OseltamivirOseltamivir

ZanamivirZanamivir

Pandemic strain vaccinePandemic strain vaccine– Minimum 5 month production timeMinimum 5 month production time– Need chicken eggs and viral seed stockNeed chicken eggs and viral seed stock

Source: CDC

Oseltamivir- Not a PanaceaOseltamivir- Not a Panacea

Limited availability (one manufacturer)Limited availability (one manufacturer)

Personal stockpiling could lead to: Personal stockpiling could lead to:

– Inappropriate useInappropriate use

– Increased resistance by the virus Increased resistance by the virus (already one documented case)(already one documented case)

– Decreased availability for the critically illDecreased availability for the critically ill

For prophylaxis, multiple courses may be For prophylaxis, multiple courses may be needed throughout flu seasonneeded throughout flu season

Human Vaccine for Avian H5N1 Human Vaccine for Avian H5N1

Effective vaccine is not yet availableEffective vaccine is not yet available– Small batches of vaccine are undergoing Small batches of vaccine are undergoing

clinical trialsclinical trials– Not ready for mass productionNot ready for mass productionUS has advance-ordered 20,000,000 dosesUS has advance-ordered 20,000,000 dosesMay not match strain that causes pandemicMay not match strain that causes pandemicSeasonal influenza vaccine does not protect Seasonal influenza vaccine does not protect against H5N1 strainagainst H5N1 strain

Public Health:Non-Public Health:Non-Pharmaceutical InterventionsPharmaceutical Interventions

Social distancingSocial distancing– SchoolsSchools– Business practicesBusiness practices– Public gatheringsPublic gatherings

Respiratory/Cough Respiratory/Cough EtiquetteEtiquette

Hand HygieneHand Hygiene

Influenza Control MeasuresInfluenza Control MeasuresEducation to encourage prompt self-Education to encourage prompt self-diagnosisdiagnosisHand hygieneHand hygieneConsider masks, if possible, for Consider masks, if possible, for symptomatic persons (then send them symptomatic persons (then send them home!)home!)

Cancellation of school/social gatherings Cancellation of school/social gatherings QuarantinesQuarantines

Have a Plan!Have a Plan!

DevelopDevelop

ExerciseExercise

UpdateUpdate

ReviewReview

ExerciseExercise

Update….Update….

CDC/EOC-PHIL

Current U.S. StatusCurrent U.S. Status

No current evidence in U.S. of highly No current evidence in U.S. of highly pathogenic H5N1 inpathogenic H5N1 in

– Wild birdsWild birds– Domestic poultryDomestic poultry– HumansHumans

Images from: http://www.usda.gov/oc/photo

ConclusionConclusion

Many unknownsMany unknowns

Simple precautions go a long waySimple precautions go a long way

Education is critical to your COOPEducation is critical to your COOP

Get employees involved in the processGet employees involved in the process

Health AdviceHealth AdviceGood Now, Good in a PandemicGood Now, Good in a Pandemic

Get your annual flu shotGet your annual flu shot– Won’t protect against a pandemic strain Won’t protect against a pandemic strain

Stay at home if you have a feverStay at home if you have a fever

Wash hands with soap or hand Wash hands with soap or hand sanitizers when you sneeze or coughsanitizers when you sneeze or cough

Get adequate sleep, eat healthy, stay Get adequate sleep, eat healthy, stay hydratedhydrated

ReferencesReferences

pandemicflu.govpandemicflu.govMichigan Department of Community Michigan Department of Community Health (www.michigan.gov/flu)Health (www.michigan.gov/flu)www.who.intwww.who.intwww.cdc.govwww.cdc.govLocal Health DepartmentLocal Health DepartmentChamber of CommerceChamber of Commerce