Pandemic Influenza

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					Pandemic Influenza
             John R. Baird, M.D.
                  Health Officer
         Fargo Cass Public Health
      -------------------------------------
    Field State Medical Officer
North Dakota Department of Health
                           April 2006
Avian Influenza – Bird Flu
Objectives
   Provide background info on influenza

   Describe avian influenza

   Discuss pandemic influenza
       Effects on community
       Preparation needed
Respiratory Infections
   Fall, Winter, Spring
   Viruses
       Rhinoviruses
       Coronaviruses
       Parainfluenza viruses
       Respiratory syncytial viruses (RSV)
       Many others
   Bacteria
       Pertussis – Whooping Cough
Influenza
   Rapid spread
   Causes epidemics
   Virus changes readily
   Serious complications – pneumonia
   Can cause severe illness & death
       Esp. in elderly & debilitated
       Approx. 36,000 deaths in USA per year
   Peak – December to March
Influenza spread




  Courtesy of Centers for Disease Control and Prevention
Influenza spread
   Airborne – droplets – esp. crowded
                   populations in enclosed spaces
   Direct contact – virus may persist on object
    for hours to days – esp. in cool, dry areas
   Incubation – 1 – 3 days
   Communicable – 1-2 days before onset of
    symptoms and 4-5 days after onset
         Possibly up to 21 days in < 12 y.o. or adults w/ avian
Influenza Symptoms
   Rapid onset of:
       Fever
       Chills
       Body aches
       Sore throat
       Non-productive cough
       Runny nose
       Headache
Influenza Virus
   Single-stranded RNA
   Type A - moderate to severe illness
       all age groups
       humans and other animals
       subtypes determined by hemagglutinin and neuraminidase
       15 subtypes - H1, H3, and N1, N2 – cause epidemics
       (H5 and H7 – avian varieties)
   Type B - milder epidemics
       humans only
       primarily affects children
   Type C - rarely reported in humans
       no epidemics
 Influenza virus
Hemagglutinin




                                                   Neuraminidase

                  A/Beijing/32/92 (H3N2)

     Virus      Geographic    Strain    Year of     Virus subtype
     type         origin     number    Isolation
Influenza Vaccine
   Composition - Inactivated virus
       Trivalent – 2005-06 antigens – (H3N2, H1N1, B)
           A/California/7/2004 (H3N2)-like
           A/New Caledonia/20/99 (H1N1)-like
           B/Shanghai/361/2002-like
   Efficacy
       Varies by similarity to circulating strains,
                age, current health status
   Duration of immunity
       <1 year
                  Vaccine Development

                         Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
        surveillance                                                       WHO/CDC)

       select strains         WHO/CDC/FDA
 prepare reassortants           CDC/FDA

  standardize antigen                       FDA

      assign potency                                    FDA

       review/license                         FDA
formulate/test/package                                   manufacturers

           vaccinate                                                       clinic
Influenza Antigenic Changes
   Antigenic Drift
       Minor change, same subtype
       Caused by point mutations in gene
       May result in epidemic

   Antigenic Shift
       Major change, new subtype
       Caused by exchange of gene segments
       May result in pandemic
Bird Flu
Avian Influenza
Avian Influenza – “Bird flu”

   Contagious disease of birds
       Influenza type A can infect humans, birds, pigs,
        horses, seals, whales and other animals
   Wild birds - migratory waterfowl – natural hosts
       Typically do not become ill
   Domestic poultry – chickens and turkeys – can
    get very sick and die
       Sudden onset of severe illness and rapid death
Avian Influenza
Bird to Bird Transmission
   Spread from wild to domestic birds
       Droppings, shared water supply
       Inhalation of airborne viruses
   Spread from farm to farm
       Bird droppings, contaminated dust, soil, equipment, vehicles,
        feed, cages, clothing, shoes
       Feet and bodies of animals (rodents)
   Spread from country to country
       Live bird markets (“wet” markets)
       International trade
       Migratory birds – wild waterfowl (ducks), sea birds, shore birds
Migratory Bird Flyways
Countries with Bird Flu
Avian Influenza
Control Measures
   Control measures
       Rapid destruction of all infected and exposed birds
       Proper disposal of carcasses
       Quarantine and disinfection of farms
       Restrict movement of live poultry

   Virus killed by heat and common disinfectants (formalin,
    iodine compounds, chlorine, and quaternary ammonia,
    waterless hand sanitizers)
       Can survive at cool temps in contaminated manure for at
        least 3 months
           1 gram of contaminated manure can contain enough virus
            to infect 1 millions birds
           Bird Flu
Bird to Human Transmission
Avian Influenza
Bird to Human Transmission
   Transmission to humans
       Directly from birds
       Bird contaminated environments
       Intermediate host – pig
           Serve as “mixing vessel”, are susceptible to both human
            and mammalian viruses


   H5N1 has a unique capacity to jump the species
    barrier and cause severe disease, with high mortality,
    in humans
Avian Influenza A (H5N1)
Confirmed human cases since ‘03
                       Cases           Deaths
   Azerbaijan            8                5
   Cambodia              6                6
   China                16               11
   Egypt                 4                2
   Indonesia            31               23
   Iraq                  2                2
   Thailand             22               14
   Turkey               12                4           As of 12 Apr 2006
   Viet Nam             93               42
   Total                194             109
 http://www.who.int/csr/disease/avian_influenza/en/
Countries with Human Cases
Can you
eat chicken?
Jacques Chirac – says YES
             Avian Influenza and
              Genetic Exchange
   Avian and human flu viruses can exchange genes
    when a person is infected with viruses from both
    species – (human vaccination important to prevent
    this)
       Gives rise to a completely new subtype of influenza
          humans would have little if any natural immunity
          If the new virus contains sufficient human
           genes, person to person transmission can occur
           (instead of from bird to humans only)
              Pandemic
Mixing of Influenza Viruses
Gene Sharing
Pandemic Influenza
   A “novel” influenza virus detected in humans
   A virus not previously known to infect humans
   Little to no immunity in the general public
   The virus will infect all age groups
   The “novel” virus spreads from person-to-person
    throughout multiple countries and continents
Pandemics Do Happen!                                                         H9*
                                                                                     1998 1999
                                                                                         2003
                                                                             H5*
                                                                                 1997 2003-2006
                                                        H7*
                                                               1980           1996 2002
                                                                                    2003 2004
                                                   H1
                                           H3
                             H2
H1                                                       1977

 1915        1925   1935   1945     1955        1965    1975          1985    1995          2005



   1918                         1957          1968                                   *Avian      Flu
  Spanish                       Asian       Hong Kong
 Influenza                    Influenza     Influenza
   H1N1                         H2N2          H3N2
Influenza Pandemics in the
Twentieth Century
   1918-19 “Spanish flu”
       H1N1 - > 500,000 died in USA, 50 million in world
       Almost half were young, healthy adults
       Died in first few days of illness
   1957 “Asian flu”
       H2N2 – 70,000 deaths in USA
   1968 “Hong Kong flu”
       H3N2 – 34,000 deaths in USA
   All seemed to have an avian influenza origin
      Worldwide Spread in 6 Months
          Spread of H2N2 Influenza in 1957
                    “Asian Flu”




Feb-Mar 1957
Apr-May 1957
Jun-Jul-Aug 1957
                      69,800 deaths (U.S.)
http://www.pbs.org/wgbh/amex/influenza/maps/
http://www.pbs.org/wgbh/amex/influenza/maps/
http://www.pbs.org/wgbh/amex/influenza/maps/
http://www.pbs.org/wgbh/amex/influenza/maps/
http://www.pbs.org/wgbh/amex/influenza/maps/
http://www.pbs.org/wgbh/amex/influenza/maps/
How is a pandemic different
from the normal influenza
season?

   There will be little warning
   There will be no vaccine available for up to 4
    to 7 months after isolation of the novel virus
   Many more will become infected and many
    more will die
Planning for Pandemic
   Public Health & Health Care response
   Local community government response
       State support
       Federal support
   Business response
   Individual response
Planning Goals
   Maintain the elements of community
    infrastructure necessary to carry out
    pandemic response
   Minimize social disruption and loss
   Reduce morbidity
   Limit mortality to high risk groups
Assumptions

    5 month warning period
        Five months between time when virus is isolated
         to pandemic.
    No vaccine will be available between 4 and 7
     months after isolation of novel virus
    It will take 5 months to produce enough
     vaccine for U.S. population (e.g., 20% of
     vaccine produced each month)
Assumptions (cont.)
       Two waves of illness will occur;
        second wave 6 months after first wave
       Limited stocks of antiviral medication
       Only zanamivir (Relenza) and
        oseltamivir (Tamiflu) appear to be
        effective against H5N1 influenza
Assumptions (cont.)
     Attack rate of 25%; persons become ill
         1,229,870 in Minnesota*
           160,550 in North Dakota*
     Hospitalization rate of 4%; hospitalizations
         49,195 in Minnesota*
          6,422 in North Dakota *
     Case-fatality rate of 1.7%; deaths
         20,908 in Minnesota*
          2,729 in North Dakota*

      * based on 2000 population estimates
Health Care Capacity

     Ventilator Surge Capacity
        ~105,000 in US
            75,000 – 80,000 in use at any given time
            100,000 in use during “normal” flu season
        Who should get a ventilator?
Image NCP 1603
Courtesy of the National Museum of Health and Medicine, Armed Forces Institute of Pathology, Washington, D.C.
1918 Failure to Meet Needs

    Severe prostration from influenza
    Deaths from starvation and dehydration
    We need to ensure that the basic needs of
     staff and the public are met
Considerations
   Staffing Shortages
   Mortuary bottlenecks
   Basic supplies and services
   Food
   Gasoline       “No one could buy things. Commodities
                    dealers, coal dealers, grocers closed
                    ‘because the people who dealt in them
                    were either sick or afraid and they had
                    reason to be afraid.”
                                        Barry, The Great Influenza
Fargo - 1918
   Oct 6 – 125 cases
   Oct 9 – 2,000 cases
   Oct 15 – The Forum - doctors & nurses near
    breakdown from exhaustion
   Oct 16 – The Forum - plea for volunteers
   1out of 3 became ill
   200 deaths from Oct – Dec 1918
    – mostly young adults
       (Fargo pop. 1920 – 21,961 – 1% died in 3 mo.)
           The Golden Ounce, A Century of Public Health in North Dakota
           – Stephen McDonough. 1989.
Preparation
   International
   National
   State
   Local Communities
   Business
   Individuals
International Efforts – WHO, CDC
    Planning & Coordination
    Monitoring & Containment




  November 2005 – WHO Phase 3
International –
   Educate
    Monitor
National – DHHS - CDC
   Planning
   Communication
   Vaccine
   Antivirals
   Monitor
   Containment
States
   Plan
   Monitor
   Lab
   Investigate
   Support
   Quarantine



          1,911 influenza cases as of 4/11/06 (last year 3,752 for season)
    Our Local Community
   November – tabletop exercise
   Community Influenza Collaborative – Ruth Bachmeier
   Many areas to address
       Public Information and Education
       Family Preparedness Plans
       Recommendations for local businesses
       Recommendations for schools/daycares
       Protecting City and County infrastructure
       Process for decision making
       Protective measures
       Corpse management
       Disease surveillance
       Laboratory issues
       Mental health issues
Business can help

   Plan for emergency
    continuation of business
   Maintain goods & services
    critical for general public
   Inform employees and
    clients
Individual preparedness

   Personal hygiene




   Get information
   Family health history
   Preparation & plans
Conclusion
   Background info on influenza, avian flu, and
    pandemics
   Predictions difficult for avian flu
   Pandemic influenza can have serious
    consequences for our community
   Preparation is important – international,
    national, state, local, business, individual
    Further Information
   Fargo Cass Public Health – 701-241-1360
       http://www.cityoffargo.com/health/
   North Dakota Department of Health – 701-328-2378
       http://www.health.state.nd.us/


   CDC        http://www.cdc.gov/flu/
               http://pandemicflu.gov/

   WHO http://www.who.int/csr/disease/influenza/en/

				
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