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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