achievements, issues and options on strategies for hpai control and prevention outbreak control...
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Achievements, issues and options on strategies for HPAI
control and prevention
Outbreak control responses – overview of country and regional field and programme
operations
Les Sims
Progress so far
• Excellent progress, cause for cautious optimism and praise
• But only first battles in a very long war• Even in countries that have made good
progress in damping down infection (Viet Nam and China) H5N1 HPAI viruses are persisting (as expected)
Why no uniform approach to this disease?
• Not dealing with a single disease situation • There are at least four different scenarios for countries or
parts of countries
Recently infected and rapidly detected, and normally low risk of virus incursion to farms (e.g. EU 2006)
Recently detected, but failure to detect early incursion - disease already widespread before action taken (most countries in SE Asia in 2003-04)
Entrenched infection (multiple widespread cases of disease reported in poultry and/or humans in the previous two years - e.g. Egypt, Nigeria, Mekong region, China, Indonesia, Pakistan?)
High risk of virus incursion (e.g. Hong Kong SAR, large parts of Russia, some countries with entrenched infection)
Why no uniform approach to this disease?
• The approach to control and prevention under each of these scenarios differs
• Standard guidelines promoting early case detection, emergency response and rapid stamping out are most appropriate for the first category (recent infection, early detection)
• This approach failed to eliminate infection in countries with entrenched infection – it will only provide temporary gains unless changes are made to those parts of the industry that allow infection to persist (and won’t detect all cases).
• Focus of presentation will be on countries/regions with ‘entrenched’ infection or in which infection is likely to become entrenched
• Including China, Lower Mekong area, Indonesia, West Africa, Egypt, and possibly Pakistan/Afghanistan and Bangladesh
What to do in places with entrenched infection?
• Get recognition that infection will not be eliminated in the short to medium term
• Strengthen veterinary services, associated legal frameworks and enforcement, and government links to industry (but some issues hard to overcome)
• Contain infection to reduce the risk to poultry and humans (risk reduction) but then consolidate these gains
• The response will not be uniform and depends on many factors (e.g. structure of poultry industry, strength of veterinary services)
What to do in places with entrenched infection?
• Identify high risk production and marketing practices (e.g. sale of commercial broilers through uncontrolled live bird markets)
• Implement feasible modifications (socially, economically, environmentally and technically) to these that minimise these risks and the harm done by the changes (winners and losers)
• Avoid creating new risks – e.g. market closures leading to underground trade (use combination of regulation and market forces to drive change)
Duck farmsGoose farms Chicken farms Other birds
Incl. wild
Duck farms
Chicken ‘Inns’
Chicken farms
Wholesale market
Retail markets
Wholesale market
Quail farms
Mainland China
Hong Kong SAR
1997
Minimal border controls
Risk
Duck farmsGoose farms Chicken farms Other birds
(no wild birds)
Chicken farms
Wholesale market/slaughterhouse
Retail markets
Wholesale market
Quail farms
Mainland China
Hong Kong SAR
2002
Chilled only
Stricter border controls
Risk
Duck farmsGoose farms Chicken farms
Other birds
Chicken farms(less farms)
Retail markets
Wholesale market
Mainland China
Hong Kong SAR
2006
Chilled only
Stricter border controls
Other birds(no wild birds)
Risk
Sl/house
Duck farms incl grazing
Goose farms Chicken farms Other birdsIncl. wild
Duck farms
Chicken holding farms’
Chicken farms
Wholesale market
Retail markets
Wholesale market
Quail farms
2007 elsewhere in Asia
Minimal border controls
Risk
Slaughterhouse
DOC Dealers
What to do in places with entrenched infection?
• If practices can’t be changed then use other measures to contain infection (e.g. vaccination)
• Set key objectives (e.g. no industrial broiler chickens
sold through live poultry markets 5 years from now)
• Develop a ‘road map’ of how to move forward towards achieving objectives
• Get empowered to make these changes
Control Consolidate Eliminate
Emergency activities
Focus on supplying emergency resources
and enhanced preparedness
Continue to dampen down infection
Focus on longer term structural changes(poultry sector and veterinary sector)
Maintain emergencypreparedness
Largely outsidecurrent planning horizons
Some farms and production sectors
will eliminate infectionand demonstrate
freedom but remain at risk
The tipping point – when to move from traditional emergency
approach to longer term approach?
• Requires a thorough assessment of the local situation – examine risk pathways
• Often do not have all the information needed due to limited surveillance capacity …….
….. but now have sufficient experience with this disease to make a crude assessment of the likelihood of early elimination following virus incursion into poultry
Predicting outcomes after incursions
Poor outcomes likely if most of the following apply:
• Millions of poultry flocks• Trade through many middlemen via poorly
regulated large live poultry markets• Large number of domestic ducks• Large populations of game birds• Limited veterinary capacity• Poor governance and little high level support
When to use vaccination?
• Demonstrated high risk of recurrence
• Specific risk high factors identified but can’t alter management (e.g. smallholder scavenging flocks, grazing ducks)
• Affordable and capacity to implement
• Define objectives of the program
• Use of vaccine as a means to reduce levels of infection is acceptable
• Provides time to gradually address the key structural issues and therefore to reduce main risk factors
Stamping out (and why no uniform culling zone)
• Decision on the extent of stamping out extent must be based on the local epidemiological situation
• The objective should be to conduct the least amount of culling compatible with disease control, and the current infection status
• Many examples of success using culling of infected premises only, especially if farms relatively isolated and efficient tracing and movement controls or combined with vaccination
• Ensure culling is an appropriate response (Culling should be subject to the same analysis as other control measures – costs and benefits, especially likelihood of sustained gains from culling)
Farm biosecurity
Movement controls and cleaning and disinfection
Communication
Major achievements• Eradication from many countries• Containment in some others• Excellent support for laboratories • Recognition that this disease will not be
eliminated from many countries in the medium to long term
• Allows a shift to measured, longer term approaches to this disease in places with entrenched infection
• From emergency management and a focus on case detection …..…… to risk detection and reduction.
• Requires political support and commitment from the highest levels of government
• Requires donors to support longer term interventions if gains in these countries are to be sustainable
• Will also lead to reduced risk of other emerging diseases
Guidance for discussion groups this afternoon
• Not about the tools and methods – we know that these work to reduce and sometimes eliminate infection if used appropriately
• Focus on the factors that limit their effective use, including political and financial factors, and ways to overcome these
• Focus on ways to reduce risks• Donors – consider absorptive capacity and
appropriateness of investments and ways to provide long term support
Thank you
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