Post on 03-Feb-2021
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Highly pathogenic avian
influenza in domestic
poultry and wild birds
Cristóbal Zepeda.Centers for Epidemiology and Animal Health USDA-APHIS /
Animal Population Health Institute, Colorado State University
A risk analysis framework
Risk analysis
� A process composed of
�Hazard identification
�Risk assessment
�Risk management
�Risk communication
Hazard identification
� Introduction of HPAIV into the
domestic poultry population
Release assessmentConsequenceassessmentExposure assessment
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Release assessment
� Define potential pathways for the
introduction of the agent
�Wild birds
�Poultry trade
Wild birds
� Identify flyways
� Few alternatives to prevent
introduction
� Wild bird monitoring will contribute to
early detection
Poultry trade
� Legal trade in poultry and poultry products
� Considered safe if based on OIE recommendations
� Illegal trade
� Pet birds
� Hobby birds e.g. fighting cocks, falcons
� Poultry products
HPAI surveillance
� Surveillance can be defined as:
information for action
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HPAI surveillance
� Surveillance in wild birds
� Information
� Action
�Domestic poultry
Emergency Emergency
responseresponseDetectionDetectionPreventionPrevention
EarlyEarly
warningwarning
HPAI comprehensive surveillance
HPAI comprehensive surveillance
� OIE information system
� FAO-EMPRES
� Promed
� Neighboring countries
EarlyEarly
warningwarning
HPAI comprehensive surveillance
� Wild birds
� Limited scope of action
� Domestic birds
� Enhance biosecurity
PreventionPrevention
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HPAI comprehensive surveillance
� Wild birds
� Surveillance of resting sites
� Testing of migratory and non-migratory wild birds
� Investigate mortality
� Domestic birds
� Targeted surveillance
� Testing of high risk populations
� Birds in proximity to wild bird sites
DetectionDetection
HPAI comprehensive surveillance
� Wild birds
� No action
recommended
� Domestic birds
� Stamp-out affected flocks
� Economic, social,
political
considerations
� Vaccination
Emergency Emergency
responseresponse
Exposure assessment
� Define potential pathways for
exposure of domestic poultry
�Proximity to wild bird populations
� Indirect contact
�Contact with infected poultry or products
Risk management
� Regionalization
�Not very effective if wild birds are involved
� Compartmentalization
�New strategy adopted by the OIE
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OIE Guidelines for AI surveillance
� No country can declare itself free from avian influenza in wild birds
� Focus of surveillance is on domestic poultry
� ‘all birds reared or kept in captivity for the production of meat or eggs for consumption, for the production of other commercial products, for restocking supplies of game, or for breeding these categories of birds’
FREE
NOT FREENOT FREE
FREE
NOT NOT
FREEFREE
BIOSECURITY BORDER
Products
Liveanimals
Genetics
Wild birds
Fomites
Illegalmovements?
FREE
Liveanimals
Genetics
Products
People andvehicles
Wildlife
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Risk management
� HACCP applied to biosecurity
� Conduct a hazard analysis
� Determine critical control points
� Establish critical limits
� Establish monitoring procedures
� Establish corrective actions
� Establish verification procedures
� Establish record-keeping and documentation procedures
In practice
� Compartment definition
�Commercial
�Backyard
�Wild birds
� Declaring free compartments
�Define compartmentalization strategy beforehand
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Infected
Free
Compartment recognition
� Seven criteria
� Definition of the compartment
� Epidemiologic separation of the compartment from potential sources of infection
� Documentation of factors critical to the definition of compartment
� Supervision and control of the compartment
� Surveillance for the agent or disease
� Diagnostic capabilities
� Emergency response, control, and notification capability
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Conclusions
� Risk analysis provides a structured framework on which to base a comprehensive disease prevention and control strategy.
� Surveillance for HPAI in wild birds will help predict the spread of the virus
� Targeted surveillance is the most effective type of surveillance both in wild and domestic birds
� Compartmentalization and enhanced biosecurity will the most effective risk management options