Avian Influenza and Influenza Pandemic Threat Global Scenario

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Avian Influenza and Influenza Pandemic
ThreatGlobal Scenario

Dr S J Habayeb, WHO Representative to India
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Subtypes of Influenza A Virus
H1
N1
H2
N2
H3
N3
H4
N4

• Many subtypes (15 H and 9 N)
• 3 subtypes have caused human epidemics
• H1N1
• H2N2
• H3N2
• Subtypes that usually infect birds but that have
  also caused infections in humans
• H5, H7, and H9

H5
N5
H6
N6
H7
N7
H8
N8
H9
N9
H10
H11
H12
H13
H14
H15
(Karl G Nicholson, et al Lancet 2003 362
1733-45)
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How Human to Human Transmission Occurs
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Recent Human Infections by Avian flu
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Current status of Avian Influenza in Poultry
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Why are we so concerned?

• Number of affected countries with avian influenza
  increasing
• Number of avian and human cases increasing
• The majority of the human population has no
  immunity
• High case fatality rate
• Human influenza viruses are circulating in Asian
  countries
• Potential of emergence of a new influenza virus

Increasing risk of human to human transmission
with pandemic potential
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Recorded Influenza Pandemics
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Recorded Influenza Pandemics
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Influenza Pandemics
Being prevented by global efforts
1918 Spanish Flu
1957 Asian Flu
1968 Hong Kong Flu
2004-05Current outbreak
Up to 50 million deaths
1-4 million deaths
1-4 million deaths
54 deaths
A(H3N2)
A(H5N1)
A(H1N1)
A(H2N2)
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Events with Pandemic Potential since 1968

• 1986 H1N1 Swine virus derived from avian source
  one severe pneumonia
• 1988 H1N1 Swine virus USA pregnant woman died
  after contact to sick pigs
• 1993 H1N2 Swine virus recombinant with avian
  H1N1 Netherlands 2 children, mild disease
• 1995 H7N7 duck virus UK adult mild
  conjunctivitis
• 1997 H5N1 avian influenza Hong Kong 18 cases /6
  ?
• 1999 H9N2 quail virus 2 mild cases
• 2003 H5N1 avian influenza Hong Kong 1 ?, 1
  disease1 related ? from pneumonia
• 2003 H7N7 avian virus Netherlands 1 ? 80
  conjunctivitis few respiratory symptoms
• 2003 H5N1 avian virus Guangdong 1 ?
• 2003 H9N2 avian virus Hong Kong 1 mild upper
  respiratory symptoms
• 2003 H7N2 avian virus New York 1 pneumonia
  (HIV-co-infection)
• 2004A H5N1 disease and death in Vietnam and
  Thailand (35 cases/24 ?)
• 2004 H7N3 avian virus Canada 2 cases
  (conjunctivitis)
• 2004B H5N1 disease and death in Vietnam and
  Thailand (9cases/8 ?)
• 2005C H5N1 disease and death in Vietnam and
  Cambodia (54cases/21 ?) plus 3...

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Influenza Pandemics Impact

• Will depend upon many factors
• Virulence of the strain
• Affected age group
• Gross attack rate
• Rates of adverse effects
• Speed of spread from country to country
• Effectiveness of pandemic prevention and response
  efforts

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Influenza Pandemics Global Health Implications

• Disease and death
• About 500 million are expected to fall ill
• A significant proportion will require medical
  care
• 6.4 28.1 hospitalizations
• 2 to 7 million deaths, even with low case
  fatality rate of 0.6
• Few weeks duration
• Several waves

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Influenza Pandemic Main Implications

• Will affect medical services and essential
  disease control functions
• Will equally affect other essential community
  services
• Public transport, police, fire brigade, food
  supplies, air traffic, petrol stations, teachers,
  administrative functions, and many other sectors
• Social and political disruption
• Considerable economic loss

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Influenza Pandemic Economic implications

• H5N1 Avian Influenza outbreak Asia 2004-05
• direct economic costs to affected nations between
  US 8 -12 billion
• death of birds and control efforts, disruption of
  production and trade
• SARS US 30 - 50 billion
• loss in lt6 months

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WHO Strategy supports the following

• Risk reduction (avoiding emergence of a new
  virus)
• Elimination of animal reservoir culling,
  slaughter, vaccines
• Protection and immunization of individuals at
  risk (e.g. cullers)
• Strengthen surveillance
• Animals
• Humans (diagnostic tests, global reporting)
• Improve pandemic preparedness
• A(H5N1) vaccine development
• Access to antiviral drugs
• Influenza Pandemic Preparedness Plans (national,
  international)

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WHO partnership

• Governments
• FAO and OIE
• Animal Health
• Food Safety
• Global Influenza Laboratory Network
• Global Surveillance
• Vaccine Development
• Antiviral Drugs
• Global Outbreak Alert and Response Network
• Technical support
• (CDC, USA NIID, Japan HPA, UK EPIET, EU NCEPH
  and FETP, Australia Pasteur and Epicentre,
  France Health Canada, Canada RIVM, Netherlands
  ICCDRB, Bangladesh)

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WHO Global Surveillance of Human
Influenza Participating Networks and Laboratories
115 National Influenza Centres, 7 WHO
collaborating centres and Referral
laboratories 175-220k samples, 15-40k isolates,
2-10,000 viruses characterized
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Global Outbreak Alert Response Network (GOARN)

• GOARN is a technical partnership, coordinated by
  WHO, providing rapid multi-disciplinary support
  for outbreak response.
• Event Management System
• Field Teams Cambodia, China, Thailand, Viet Nam,
  DPR Korea and Indonesia

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WHO Pandemic Phases

• Inter-pandemic Period
• Phase 1 no novel influenza virus subtypes
  detected in humans
• Phase 2 same, but circulating animal virus
  posing significant risk to humans
• Pandemic Alert Period
• Phase 3 human infection with a novel subtype but
  no h-t-h transmission
• Phase 4 small cluster with h-t-h transmission
• Phase 5 larger cluster with h-t-h transmission,
  virus becoming increasingly adapted to humans
  (substantial pandemic risk)

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WHO Pandemic Phases (contd)

• Pandemic Period
• Phase 6 Increased and sustained transmission in
  the general population
• Post Pandemic Period
• Return to Inter-pandemic Period

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(No Transcript)
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Joint Monitoring Group on Avian Influenza

• Ministry of Health Family Welfare
• Indian Council of Medical Research
• Department of Animal Husbandry
• World Health Organization

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Department of Animal Husbandry, Dairy
FisheryMinistry of Agriculture

• 26,700 veterinary hospitals/ dispensaries, and
  28,200 S.centres and mobile dispensaries.
• 250 disease investigation laboratories in the
  states.
• A Central Disease Diagnostic Laboratory and five
  Regional Disease Diagnostic Laboratories at Pune,
  Kolkata, Bangalore, Jalandhar and Guwahati.
• High Security Animal Disease Laboratory (BL-4) in
  Bhopal.
• State Veterinary college labs, Labs of ICAR and
  private sector also are available.

Source Animal Husbandry Commissioner
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Influenza pandemic
Summary messages

• Another influenza pandemic will certainly occur
• We do not know if it is going to be H5N1. We have
  never been as close to the next one since 1968
• Influenza pandemics cause global health
  emergencies, but the damage can be reduced with
  adequate preparedness
• Various scenarios of health impact of influenza
  pandemic exist. Even the most optimistic one
  causes concern
• National pandemic preparedness is the key
• We have a window of opportunity to act, and this
  is right now!