Strategies for Controlling Animal Influenza and Implications for Human Health

1. Strategies for Controlling Animal Influenza and Implications for Human Health Les Sims Asia Pacific Veterinary Information Services apvis@bigpond.net.au

2. Background • Animal influenza is not eradicable • Possible to eliminate certain strains of virus • Equine influenza in Australia • H5N1 HPAI from most infected countries

3. Background • Available control measures for influenza in animals are well described • How and when applied, more complex • Measures are used in combination • Not always used appropriately • Any measure applied inappropriately will hamper control • Control in animals usually reduces exposure of humans to animal influenza viruses

15. Vaccination

16. Surveillance and disease reporting systems • Underpin control programs • In many countries remain weak • Mandatory reporting of infection is only required for some subtypes in selected species (e.g. H5/H7 in poultry - NAI). • No international obligation to report cases of swine influenza (unless novel disease/strain)

17. Surveillance and disease reporting • Farmers usually have few incentives to report animal influenza • They can face significant disadvantages if they do • Consequences of surveillance

18. Influenza viruses in animals Two broad ‘categories’ of animal influenza viruses - those that countries choose to live with (but still subject to controls at individual farm level) • those they attempt to eliminate

19. Control measures • Measures applied depend on: - the virus subtype (e.g. H5, H7 (NAI) viruses versus H9 in poultry); - the species involved (e.g. chicken versus wild bird) - the country where infection occurs (e.g. Australia versus Vietnam) • Leads to variations in the objectives of animal influenza control programs from place to place

20. Objectives of different parties Public health practitioner perspective/objective • Minimise exposure of humans to animal influenza viruses

21. Objectives of different parties Commercial farmer perspective/objective Control influenza until: - it no longer has a significant effect on performance or profits • farmers are sure they will retain key markets (including export markets) • Legitimate concerns about effects on sales • Some influenza viruses are subject to state and industry supported ‘eradication’ campaigns when they occur

22. Objectives of different parties Smallholder/household producer perspective • Low input systems for food security/income diversity • Some driven by poverty • Influenza only considered a problem if it causes severe losses (due to disease or to the control measures applied, including losses of markets)

23. Areas of concern – human health 1. The difficulties encountered in eliminating Influenza A(H5N1) viruses from poultry in countries where infection is endemic - Risk to humans from influenza A(H5N1) will persist for at least the next 5 to 10 years

24. 2 0 0 6 1996 2007 2003 2003

25. Areas of concern - countries with endemic infection • Why have these countries remained endemically infected ? • Three main factors • Nature of the production and marketing systems

26. Reproduced from FAO/USAID Atlas of poultry production

30. Areas of concern - countries with endemic infection ii) Quality of veterinary and animal production services iii) Commitment from public and private sector to virus elimination (not just containment)

31. Areas of concern – human health 2. Large scale animal influenza vaccination programs • Need to balance benefits versus concerns • Need to understand objectives of vaccination program - effects of vaccination on antigenic characteristics of viruses • autogenous vaccines (especially in pig production) • effects of ‘silent’ infection (need for modified surveillance and reporting signals) • Need better(user friendly) vaccines

32. Areas of concern – human health 3. The trend towards larger industrialized production units • Not a recommendation of international agencies for influenza control • Farm workers as a bridge to communities • Potential for looser ties to government (in house testing) • Potential for negative effects on poor

33. Areas of concern - trend towards larger units • 50% increase in human population in next 40 years – predominantly urban • Pig and poultry production expected to increase dramatically • Will provide opportunities for emergence of novel influenza viruses

34. Areas of concern – human health 4. Globalization and increased trade in livestock products • Most introductions of avian influenza by trade in live poultry probably occur across land borders • Most international trade in live poultry is in day old chicks (virus not vertically transmitted)

35. “If a pig coughs in Mexico the world should know about it” • Moves to improve surveillance and early identification and containment of potential human pandemic influenza viruses are laudable • Likely to fall short of expectations

36. Could we have stopped the 2009 pandemic with early detection? • If the 2009 influenza A(H1N1) pandemic virus had been detected in pigs in January 2009 what measures would have been implemented? • Not the first North American-Eurasian reassortant pig virus • Few characteristics to suggest it would be readily transmissible between humans • Low probability that such a virus would be detected when it first emerged (i.e. before spreading to other sites)

37. Pre-emptive action • Clear criteria are needed on: - when action will be taken to contain/eliminate newly emerged strains of interest in animals; - the measures that will be used; and • the support that will be provided to producers and countries affected by the measures.

38. Pre-emptive action • To improve success, actions proposed should not disadvantage transparent countries or alienate farming communities • Communities need to understand and see the benefits in making changes and of being involved in surveillance – no simple solution • Close associations between humans and animals is not restricted to developing countries

40. Thank you for your attention

41. Acknowledgements • I have been privileged to work in Asia for the past 17 years. • The observations and views in this presentation are personal but developed while working for a number of organizations, including the Government of Hong Kong, FAO, the World Bank, IDRC and PATH. • I wish to thank my many colleagues globally, and especially in Hong Kong, Vietnam, Cambodia, Mainland China and Thailand, who have worked with me, shared their expertise and helped to shape my views on animal influenza. • I would like to thank the Influenza Options team for inviting me to speak at the conference.