Avian Influenza: Control of Recent Avian Influenza Outbreaks
David E. Swayne OIE Collaborating Centre for Research On Emerging Avian Diseases, FAO Reference Centre for Avian Influenza, and Exotic & Emerging Avian Viral Diseases Research Unit SEPRL, ARS, USDA, Athens, Georgia, USA
Avian Influenza (AI) • Orthomyxovirus: RNA, 8 gene
segments, pleomorphic, enveloped • Internal proteins: all avian influenza viruses are type A
• Protein projections on the surface: – 16 hemagglutinin subtypes (i.e. H1, …, H5, H6, H7….H16) – 9 neuraminidase subtypes (i.e. N1, N2, N3….N9)
• Vary in disease production (chickens):
– Low pathogenicity (LP): local -mild respiratory disease and egg drop – High pathogenicity (HP): systemic deadly disease (some H5 & H7 AIV)
35 HPAI Disease Events 1. 1959: Scotland, H5N1 2. 1961: S. Africa, H5N3 3. 1963: England, H7N3 4. 1966: Canada, H5N9 5. 1975: Australia, H7N7 6. 1979: Germany, H7N7 7. 1979: England, H7N7 8. 1983-84: USA, H5N2 9. 1983: Ireland, H5N8 10. 1985: Australia, H7N7 11. 1991: England, H5N1 12. 1992: Australia, H7N3 13. 1994: Australia, H7N3 §14. 1994-95: Mexico, H5N2 §15. 1995 & 2004: Pakistan, H7N3 16. 1997: Australia, H7N4 17. 1997: Italy, H5N2 *§18. 1996-2013: Eurasia/Africa, H5N1 (“panzootic”) 19. 1999-2000: Italy, H7N1
20. 2002: Chile, H7N3 21. 2003: Netherlands, H7N7 22. 2004: USA, H5N2 23. 2004: Canada, H7N3 24. 2004, 2006: S. Africa, H5N2 (ostriches) §25. 2005: N. Korea, H7N7 26. 2007: Canada, H7N3 27. 2008: England, H7N7 28. 2009: Spain, H7N7 29. 2011-3: S. Africa, H5N2 (Ostriches) 30. 2012: Chinese Taipei, H5N2 § 31. 2012-4: Mexico, H7N3 32. 2012: Australia, H7N7 33. 2013: Italy, H7N7 34. 2013: Australia, H7N2 35. 2014: S. Korea, H5N8 *Largest epizootic in 50 yrs §Vaccine used in the control strategy
HPAI (7/1/2012-2/7/2014): 18 countries
H7N7 Italy H7N3 Mexico
H5N1
H5N2 S. Africa
H5N1 HPAI 12 countries – poultry, wild birds, humans
H5N2 HPAI
H5N8 HPAI
H7N2 HPAI
S. Africa – ostriches S. Korea – ducks and otherAustralia - layers Chinese Taipei – native poultry H7N3 HPAI chicken Mexico - layers
H5N1
H5N8 S. Korea H5N2 Chinese Taipei
H7N7, H7N2 Australia
H7N7 HPAI Italy – poultry Australia - layers
Epizootic Metrics • Number of countries affected: – 33: single countries – 2: multiple countries
World Poultry 58 billion/yr
• 1996-present H5N1 – 63 countries Asia, Europe and Africa • 2003 H7N7 – The Netherlands, Belgium & Germany Dead/culled 250.000.000 200.000.000 150.000.000 100.000.000 50.000.000 0
?
Dead/culled
Control Strategies Eradication is the only strategy for HPAI Historical “Stamping-out” Components: • Diagnostics and surveillance • Enhanced biosecurity (including modifications to the way poultry are reared and sold, quarantine, movement management, and cleaning and disinfection) • Elimination of infected poultry (culling) • Education (including behavioral change communications) • Decreasing host susceptibility (vaccines/vaccination & host genetics)
There is no “one control strategy”
Epizootic Metrics
S. Korea
Taiwan
Australia
S. Africa
Spain
Canada
England
Italy
USA Canada
Ne-BelGmn Chile
Italy
Australia
Australia
England
Australia
Australia
Italy
Ireland USA
Australia
Canada
England
S. Afr.
Scotland
Traditional stamping-out (30)
Germany England
S Africa
Timeline HPAI:
195 196 196 196 196 196 196 196 196 196 196 197 197 197 197 197 197 197 197 197 197 198 198 198 198 198 198 198 198 198 198 199 199 199 199 199 199 199 199 199 199 200 200 200 200 200 200 200 200 200 200 201 201 201 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 2013 2014
Vaccination included (5)
Pakistan
Mexico
N. Korea
Asian-African-European H5N1
Mexico
• 25 epizootics, < 1 year • 27 epizootics, stamping-out alone; mostly leading to eradication • Vaccination - immediate positive impact on HPAI prevention & management (disease & mortality) – Doses vaccine used, H5N1 HPAI > H7N3 HPAI Mexico > H7N3 HPAI Pakistan
• Stamping-out alone was associated with shorter eradication times than Stamping-out + Vaccination programs (Pavade et al., OIE Sci Tech Rev 30(3):661-671, 2011)
Epizootic Metrics 1) Vaccination added as a component with 5 epizootics a) Traditional stamping-out programs did not eradicate, or b) Resources were not available to accomplish stamping-out
2) 5 HPAI epizootics used vaccines and vaccination as control element: a) b) c) d) e)
Mexico H5N2 (1995- last HPAI case 6/1995) Pakistan H7N3 (1995- last case 2004) N. Korea H7N7 (2005– last case 2005) Asia/Africa/Europe H5N1 (1996-present) Mexico H7N3 (2012-present)
3) Vaccination used as a tool to reduce infection pressure, allow food security (poverty prevention), control of the disease, and development of infrastructure to eradicate
Improper vaccination program Doses of Vaccine (millions): 2002-2010 (Total >113b) 120000
Swayne et al., OIE Sci Tech Rev 30(3):839-870, 2011
103715(90.99%) 100000
80000
60000
40000
20000 8
(4.65%) 5081 0,816
86
(2.32%) 2643 0,006
(1.43%) 35
2,8
0,068
2,2
108
425
6,3
0
14 countries vaccinated poultry against HPAI (2002-2010) • Preventive (5.91)
10/10 (7.07) 9/10 (