Avian Influenza The European experience

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Avian Influenza The European experience
Alberto Laddomada European Commission, DG Health
and Consumer Protection Unit E2 Animal Health
and welfare, zootechnics
Bangkok, 30 May 2004
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Avian Influenza viruses

• Are very variable
• The risk posed for animal and public health
  posed is largely unpredictable, however it may be
  very serious
• Cannot be eradicated from the wild life
  reservoir
• Once introduced in domestic birds their
  control/eradication is often very difficult
• Very big challenge for scientists, decision
  makers and risk managers

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Low Path and High Path Influenza viruses

• The Low Pathogenic Avian Influenza (LPAI)
  viruses occur in migratory waterfowl worldwide
  and may spread to domestic poultry via direct
  contact or due to contaminated faeces
• LPAI viruses in poultry are usually sub-clinical
  and may spread unnoticed
• Some LPAI viruses may then mutate from Low
  Pathogenic into the Highly Pathogenic form (HPAI)

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EU Control Measures for HPAICouncil Directive
92/40/EEC

• Stamping out
• Zones with movement restrictions for live poultry
  
• Restrictions for the use of fresh poultry meat
  with specific health mark
• Emergency vaccination possible
• Cleaning and disinfection
• Contingency plans

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Stamping - out policy

• Culling of all poultry
• infected
• suspected of being infected
• suspected of being contaminated
• at risk preventive killing
• - decrease susceptible population
• - reduce virus spread and shedding
• destruction of their carcasses

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Area restrictions for infectious disease
Scenario 1 Control by measures defined in the
basic legislation
Surveillance Zone

• Measures
• Census-identification
• of holdings
• Veterinary inspections
• Movement controls

Protection Zone
x km
x km
y km
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Area Restrictions for infectious disease
Scenario 2 Additional measures
Surveillance Zone
Buffer Zone
x km
x km
Protection Zone
y km
Continuous review of the disease situation at the
Standing Committee on the Food Chain and Animal
Health and further appropriate measures adopted
as necessary
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Avian Influenza control experience in Italy

• 1997-2003 six epidemic waves of LPAI and HPAI
  in Northern Italy (H5N2, H7N1, H7N3)
• major economic consequences
• no public health consequences
• both stamping out and vaccination (LPAI only)
  used for disease control
• AI eradicated from domestic poultry

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AI risk factors in Northern Italy

• migratory waterfowl pathways
• mix of industrially reared poultry species
  (broilers, hens, turkeys, geese, quails, etc.),
• density of poultry
• movements and trade in live birds
• frequent indirect contacts between farms
  (personnel, lorries, etc.)

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HPAI control in Italy (1999-2000)

• Result of LPAI virus circulation and its
  mutation into HPAI
• Rigorous stamping-out applied (Council Directive
  92/40/EEC)
• HPAI eradication achieved only after massive
  depopulation and prohibition of restocking
• disease situation continuously reviewed by the
  Commission and the Member States in the Standing
  Committee gt several additional measures adopted,
  including zoning/regionalization

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LPAI control in Italy (1997-2003)

• The insufficient control of LPAI in 1998/99
  resulted in a serious HPAI epidemic
• LPAI surveillance implemented, including
  sero-surveillance
• Further LPAI incursions in 2000/01 and then
  2002/03
• Combination of stamping-out, controlled
  slaughter and vaccination (DIVA strategy)
  successfully applied LPAI eradicated, LPAI gt
  HPAI mutation prevented
• Better results in the first vaccination campaign
  than in the second one

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The DIVA vaccination strategy (Differentiating
Infected from Vaccinated Animals)

• Based on
• heterologous vaccine strain (same H,
  different N)
• very strict monitoring/surveillance
• - appropriate discriminatory test
• - sentinel birds
• controlled marketing of live poultry and
  products from vaccinated / non infected animals
  (also outside Italy)

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From Marangon et. al, 2004
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HPAI epidemic in the NL in 2003

• Probably due to H7N7 LPAI virus introduction in
  an open-air laying hen farm gt mutation into HPAI
• 241 outbreaks areas with very high density of
  poultry farms also backyard (non-commercial)
  flocks involved
• secondary limited spread of disease to bordering
  countries (Belgium and Germany)
• Human health impact (83 cases of conjunctivitis
  /one death)
• Limited spread of virus to pigs

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HPAI outbreak in the NL in 2003

• Draconian stamping-out policy adopted
• 30 million poultry culled and destroyed both in
  intensive and backyard farms
• Major logistic problems for slaughtering
  poultry, safe disposal of manure, etc.
• heterologous vaccination (H7N1) applied to
  protect birds in zoos
• Continuous review of the situation at EU level
• Several special decisions adopted
• Major economic and social impact

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CONCLUSIONS

• HPAI is the most devastating disease of poultry
• Its control has been proven to be very difficult
• The disease may have very serious public health
  consequences and impact on the media and the
  public
• There is a need to improve AI prevention and
  control world-wide
• Surveillance and control measures must also
  address the LPAI risk
• Health standards on international trade must
  reflect the different level of risks posed by
  LPAI and HPAI

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What is being done in the EU to improve AI
control?

• monitoring and surveillance in the Community
  since 2002
• review and approval of contingency plans
• review of legislation (Directive 92/40/EEC)
• - definition (different measures for LPAI and
  HPAI)
• - vaccination
• - compartmentalization
• debate at OIE on international trade standards

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Thank you!