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Pandemic Influenza
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Influenza is usually a respiratoryinfection
TransmissionRegular person-to-person transmission
Primarily through contact with respiratorydroplets
Transmission from objects (fomites)possible
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Transmission of Influenza Limited studies, varying
interpretations
Contact, droplet, and droplet nuclei
(airborne) transmission all likelyoccur
Relative contribution of eachunclear
Droplet thought most important Coughing, sneezing, talking
Most studies either Animals or human experiments
under artificial conditions Outbreak investigations
Unclear of infection source
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Key Characteristics
Communicability
Viral shedding can begin 1 daybefore symptom onset
Peak shedding first 3 days ofillness
Correlates with temperature Subsides usually by 5-7th day
in adults
can be 10+ days in children
Infants, children and theimmunocompromised mayshed the virus longer
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Incubation period Time from exposure to onset of symptoms
1 to 4 days (average = 2 days)
Seasonality
In temperate zones, sharp peaks in wintermonths
In tropical zones, circulates year-round with
seasonal increases.
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Clinical Illness, Seasonal
Influenza Abrupt onset
Fever and constitutional symptoms: bodyaches, headaches, fatigue
Cough, rhinitis, sore throat
GI symptoms and myositis more common inyoung children
Sepsis-like syndrome in infants
Complications: viral and bacterial pneumonia,febrile seizures, cardiomyopathy,encephalopathy/encephalitis, worsening
underlying chronic conditions
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Vaccination
Influenza vaccine is the best prevention forseasonal influenza.
Inactivated viruses in the vaccine developed fromthree circulating strains (generally 2 Type A and 1
Type B strain)
Therefore, seasonal flu shot only works for 3 influenzasubtypes and will not work on pandemic strains.
Live, intranasal spray vaccine for healthy non-
pregnant persons 5-49 years Inactivated, injectable vaccine for persons 6
months and older
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Non-Pharmaceutical Interventions
Voluntary isolation of sick people
Voluntary quarantine of healthy contacts School closures
Social distancing
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Avian Influenza
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Avian Influenza
Type A influenza Endemic in birds
H5, H7 subtypes can cause seriousdisease or death in wild birds; oftencause death in poultry
Virus in saliva and feces of wildbirds and poultry can be directlytransmitted to humans and otheranimals
Can contaminate clothing,equipment, water, feed
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H5N1 Avian Influenza Currently spreading through Asia, Africa,
Europe, Middle East Can be highly lethal to domestic poultry and
other animal species
Occasional human cases but no efficient humanto human transmission yet
Virus of greatest concern for pandemic potential,
but other viruses in animals also of concern
*As of March 8, 2007
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Characterized by ability to change Continually yearly epidemics
Drastically sporadic pandemics
Influenza Viruses
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Influenza Viruses Classified into types A, B, and C
Only Types A and B cause
significant disease Types B and C limited tohumans
Type A viruses More virulent Affect many species
C Goldsmith, CDC
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Influenza A Viruses Influenza A viruses categorized by subtype
Classified according to two surface proteins
Hemagglutinin (H) 16 known Site of attachment to host cells Antibody to HA is protective
Neuraminidase (N) 9 known Helps release virions from cells Antibody to NA can help modify disease severity
N
H
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A / Sydney / 05 / 97 (H3N2)
Nomenclature
Virus type Strain number Virus subtype
Place virus
isolated
Year isolated
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H5N1 in Other Animals
H5N1 can infect otheranimals:
Pigs (China, Vietnam) Dogs
Domestic cats; has
infected civet cats
Tigers, leopards(Thailand, China)
Tiger-to-tigertransmission (Thailand)
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Avian Influenza Low pathogenic AI (LPAI)
Most common influenza infection in birds Causes mild clinical and unapparent infections
May be any subtype (H1 to H15)
Highly pathogenic AI (HPAI) Some H5 or H7 subtypes
Causes severe illness in poultry and often death
LPAI H5 or H7 subtypes can mutateinto HPAI H5 or H7 subtypes
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Migratory
water birds
Domestic birds
Avian influenza
United Kingdom Department of Health
All known Influenza Asubtypes
Circulate in wild birds&
Infect domestic birds.
Wild birds =Reservoir for Influenza A strains
&source for viruses infecting other
species.
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H5N1 Epizootic 2003-2006
Since December 2003, >50 countries have
reported H5N1 amongdomestic poultry and wildbirds
Current outbreaks in a
many countries Expanded from Asia to the
Middle East, Europe, andAfrica
Largest epizootic of avianinfluenza ever described Over 200 million birds died
or destroyed
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H5N1 Clinical Features Case fatality ratio: 60% Median age: 20 years (range 3 mos-75
yrs)* Previously healthy children, young adults
Incubation: 2-8 days
Fever, cough, shortness of breath,diarrhea
Pneumonia, severe respiratory disease Leukopenia, multisystem organ failure
Beigel JH, et al. NEJM 2005;353:1374-85 *WHO WER;26:249-260
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Clinical illness with H5N1
compared with typical humaninfluenza illness
More severe illness in younger persons
Primary viral pneumonia appears to bemore common and with rapid onset
Incubation period may be longer Duration of infectious period likely longer,
particularly among adults
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Avian Influenza in HumansYear Subtype Location Cases Deaths
1996 H7N7 United Kingdom 1 0
1997 H5N1 Hong Kong 18 61998 H9N2 China 6 0
1999 H9N2 Hong Kong 2 0
2002 H7N2 United States 1 02003 H7N2 United States 1 0
2003 H9N2 Hong Kong 1 0
2003 H5N1 Hong Kong 2 12003 H7N7 The Netherlands 89 1
2004 H7N3 Canada 2 0
2003-07 H5N1 Worldwide 281* 169* As of March 21, 2007
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H5N1 Possible Travel Routes
Legal poultry business
Illegal bird trade
Untreated fertilizer
Migrating birds
Humans (contaminated
objects)
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HumanHumanvirusvirus
ReassortantReassortant
virusvirus
NonNon--humanhuman
virusvirus
Re-assortment and
Direct Transmission
DIRECTDIRECT
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What is Pandemic Influenza?What is Pandemic Influenza? Pandemic: epidemic spreadingPandemic: epidemic spreading
around the world affecting hundredsaround the world affecting hundreds
of thousands of people, acrossof thousands of people, acrossmany countriesmany countries
Flu pandemics: global influenzaFlu pandemics: global influenza
epidemics of newly emerged strainepidemics of newly emerged strain
of influenza thatof influenza that
passes easily from person to personpasses easily from person to person
causes severe diseasecauses severe disease
Essentially no preEssentially no pre--existing immunity;existing immunity;
every body at riskevery body at risk
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Influenza Pandemic VirusesRequirements:
A new influenza A subtype can infect humansAND
Causes serious illness
AND
Spreads easily from human-to-human
The first two prerequisites have been met,
but not the last
Each new human infection is an opportunity for thevirus to change
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Pandemic InfluenzaPandemic Influenza
Timing unpredictableTiming unpredictable
High illness rates across age groupsHigh illness rates across age groups
Increased mortalityIncreased mortality
Higher proportion deaths in youngerHigher proportion deaths in youngerpersonspersons
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Estimated Mortality fromInfluenza Pandemics
1918-19 (H1N1)>500,000 deaths US20 -100 million worldwide
1957-58 (H2N2)70,000 deaths US
1968-69 (H3N2)34,000 deaths US
C b t P d i
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Concerns about Pandemic
Influenza Rapid global spread (morbidity and mortality)Rapid global spread (morbidity and mortality)
Shortages and delaysShortages and delays vaccines and antiviralvaccines and antiviralmedicationsmedications
Increases burden on hospitals and outpatientIncreases burden on hospitals and outpatientcare systemscare systems
Disrupts national and community infrastructuresDisrupts national and community infrastructures
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Inter-species Transmission
and Pandemics Many reports of transmission animal
influenza viruses to humans that do notresult in pandemic E.g. Swine Flu 1976
230 infected, 13 hospitalized, 1 death No sustained transmission beyond Ft. Dix, NJ
But, because pandemics may be so
devastating, vigilance and planning critical
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WHO Stages of a Pandemic Inter-pandemic period
Pandemic alert period
Pandemic period
Post pandemic period
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WHO Phases of a PandemicInter-pandemic Period
Phase 1: No new Influenza virus subtypes in
humans
Phase 2: No new virus subtypes in humans;animal subtype poses a risk of humandisease
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Pandemic Alert Period
Phase 3: Human infection with novel virus;no instances of human-to-human spread
Phase 4: Small, localized clusters of human-to-human spread
Phase 5: Larger clusters, still localized; virusadapting to humans
WHO Phases of a Pandemic
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Pandemic Period
Phase 6: Increased and sustainedtransmission in the general population.
Post Pandemic Period
Recovery phase
WHO Phases of a Pandemic
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Possible Scenarios in the Philippines
No avian influenza in birds, thus no bird-to-human transmission
Avian influenza in birds, bird-to-humantransmission
Avian influenza in birds, bird-to-humantransmission, human-to-humantransmission
No avian influenza in birds, human
cases from other countries due to novelvirus
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Non-pharmaceutical interventions (NPIs)
Measures other than vaccines and antivirals that
may reduce the risk of transmission of a influenzato individuals and communities
NPIs can be implemented at borders, or at the
level of the community and the individual
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Wh NPI b i
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During the first few months after a pandemic
begins: Vaccine made from a pandemic strain will probablynot to be available
Antivirals may be insufficient in quantity, ineffective
and/or difficult to distribute in a timely way In many countries of the world, it may be some
time before either vaccine or antivirals areavailable in sufficient quantity
Why are NPIs being
considered?
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E l f ibl
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Examples of possible
consequences of school dismissal Families
Children Missed school/disruption of education
School-meal dependent children lose meals, nutrition
Happy not to have to go to schools
More time with friends
Parents Missed work/lost income
Childcare
Intangible costs (e.g., stress)
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Examples of possible
consequences of school dismissal Communities
Lost productivity due to work absenteeism Industries that support school functioning
lose business (e.g., school meal industry)
Additional transmission caused by childrenre-congregating
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Other Prevention Strategies Community
International ports of entry Individuals
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CDC Quarantine Stations
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Possible screening measures* Traveler questionnaire and/or interview
Visual inspection
Fever screening (temperature check) Specimen collection and testing (secondary)
*Effectiveness unknown; dependent on clinical syndrome
and other factors (e.g. time of flight)
CDC Quarantine Stations
Ports of entry NPIs
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Infection Control Measures All interventions should be used in
combination with infection control measuresincluding:
Hand hygiene
Cough etiquette
Environmental cleaning
Personal protective equipment such as facemasks
Maintaining essential servicesMaintaining essential services
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Persons providing
Emergency and disaster response
Maintenance of peace and order
Transportation, including air traffic controllers Utilities water, electricity
In an explosive spread, efforts and resourceswill be shifted to maintenanceof essential services
Arrange ahead places of duties and schedule toArrange ahead places of duties and schedule to
cover the required duties during the pandemiccover the required duties during the pandemic
Back upBack up
Maintaining essential servicesMaintaining essential services
C i ith i d d d f h lthC i ith i d d d f h lth
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manpower augmentation antipyretics, analgesics, liniments andantibiotics for home care
triaging of cases in out-patient clinics
Shortage of beds, equipment and supplies Only serious and urgent cases will be
admitted Back-up / buddy system Supplies of relevant drugs (e.g.
antibiotics) and equipment (e.g. Ventilator)
Secondary and tertiary care
Coping with increased demand for healthCoping with increased demand for health
services and goodsservices and goodsPrimary care
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What is the DOH doing?What is the DOH doing?
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Establishment of unified private sector network, primarily the civilsociety organization and the business sector
Capability building of key people from the central and regionaloffices of DA, DOH and DENR and of Agricultural and HealthOfficers in 20 critical sites covering 103 municipalities
Consultative Forum for DOH Regional Coordinators on SARS, AI &Other Emerging Infectious Diseases Provided the trained trainors with updates from DOH and DA
Obtained feedback from the participants on their field experiences Gathered baseline information from the core trainors on the impact of
TOT & the previous regional training series for processing throughSWOT analysis
Presentation of the revised course outline
Finalization of the regional action plan
What has been accomplishedWhat has been accomplished
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Training of DOH-retained and selected local
hospitals Regional Training Series
Fighting a Pandemic: Training of LGUs onPreparedness for SARS, Avian Influenza and OtherEmerging Infectious Diseases
Aimed to build the capacity of PHOs / MHOs / CHOs in AI /SARS / EID preparedness and response
Development and dissemination of informationon avian influenza
What has been accomplishedWhat has been accomplished
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Ban importation of poultry and its products fromBan importation of poultry and its products from
AIAI--affected countriesaffected countries Assist Local Government Units (Assist Local Government Units (LGUsLGUs) in) in
drafting their Preparedness and Response Plansdrafting their Preparedness and Response Plans
Conduct AIPP lectures and AI updates toConduct AIPP lectures and AI updates torequesting parties & concerned groupsrequesting parties & concerned groups
Assessment of prior surveillance work andAssessment of prior surveillance work and
institutionalization of surveillance activitiesinstitutionalization of surveillance activities
What has been accomplishedWhat has been accomplished
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Orientation of Barangay Health
Emergency Response Teams on AvianInfluenza
Aimed at orienting the BHERTS on Avian
Influenza
Provision of PPEs to CHDs & DOHretained hospitals designated as AIreferral hospital
What has been accomplishedWhat has been accomplished
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Moving ForwardMoving Forward Conduct of simulation exercises as teaching, planning
and assessment tools
Expansion of the information campaign to the localcommunities through a collaborative effort of the publicand the private sector
Continuing efforts for strengthening of surveillance of
birds and humans Capacity building of DOH-retained and local hospitals forresponse to serious infectious disease disasters
Strengthened participation of other government agenciesand the private sector for avian and pandemic influenzapreparedness
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Continuing efforts to prepare the public healthand hospital systems for avian and pandemicinfluenza that could further lay the foundation tostrengthen preparedness to any severeemerging infectious disease
Training of more Municipal Agricultural andHealth Officers for Avian and PandemicInfluenza from 1200 municipalities
Training of Barangay Health EmergencyResponse and Rapid Action Teams Pilot testing of the Early Warning System
Moving ForwardMoving Forward
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Moving ForwardMoving Forward Conduct of real time simulation exercises to testConduct of real time simulation exercises to test
the AIPPthe AIPP
Expanding areas for disease surveillanceExpanding areas for disease surveillance Intensification of IEC campaign in the twentyIntensification of IEC campaign in the twenty
(20) critical areas for AI, international borders(20) critical areas for AI, international borders
and coastlinesand coastlines
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Moving ForwardMoving Forward Review of the AIPP for further improvement of
disease control and eradication protocols
Training of more military men and volunteers forimmediate response in the event of an outbreak
Establishment of AI laboratories in Luzon,
Visayas and Mindanao to complement activitiesof the National Influenza Center (RITM)
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Critical in averting a potentialpandemic:
Early Recognition
and Containment