DEVELOPMENT OF A MODEL FOR ASSESSING WHIRLING

DISEASE RISK

• Risk analysis is a tool intended to provide Risk analysis is a tool intended to provide decision makers with an objective, repeatable decision makers with an objective, repeatable and documented assessment of the risks posed and documented assessment of the risks posed by a particular course of action. by a particular course of action.

What is a Risk Analysis?What is a Risk Analysis?

• Risk analysis is intended to answer;Risk analysis is intended to answer;

• What can go wrong?—the hazard identification,What can go wrong?—the hazard identification,

• How likely is it to go wrong and what would be How likely is it to go wrong and what would be the consequences of its going wrong?—the risk the consequences of its going wrong?—the risk assessment, andassessment, and

• What can be done to reduce either the likelihood What can be done to reduce either the likelihood or the consequences of its going wrong?—risk or the consequences of its going wrong?—risk management.management.

Risk AnalysisRisk Analysis

• Hazard identificationHazard identification– Myxobolus cerebralisMyxobolus cerebralis

• Risk assessmentRisk assessment• Release assessmentRelease assessment• Exposure assessmentExposure assessment• Consequence assessmentConsequence assessment• Risk estimationRisk estimation

System 1(source)

System 2Overt disease

FACTORS AFFECTING PARASITE INTRODUCTION

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pathways for parasite introduction and dispersalpathways for parasite introduction and dispersal viability of parasite during introductionviability of parasite during introduction

Release AssessmentRelease Assessment

System 1System 1(source)(source)

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FACTORS AFFECTING PARASITE

ESTABLISHMENT

System 2System 2 OvertOvertDiseaseDisease

Encounters between parasites and hostsEncounters between parasites and hosts

Infection of worm hostInfection of worm host

Proliferation of infectious stagesProliferation of infectious stages

Exposure AssessmentExposure Assessment

System 1(source)

System 2Overt disease

FACTORS AFFECTING DISEASE MANIFESTATION IN

FISH

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pathways that are conducive to the development pathways that are conducive to the development of the parasite and whirling disease in the fishof the parasite and whirling disease in the fish

Consequence AssessmentConsequence Assessment

Introduction

RecreationalActivities

Fish Transfer

RestorationActivities

Commercial Activities

Natural Dispersal

Boaters, anglers

Streamenhancement

FryJuveniles

Adults

Free myxospores, triactinomyxons

Avian Wild fish Worms

Infected fish products

Species

Source

Introduction frequency

Establishment &Proliferation

Fish

Species susceptibility

Population densityBiotic Community

Spatial/Temporal Overlap

Worms

System Modification

Environment

Strain susceptibilityPopulation density

Temperature

Flow

Substrate

Organismslife histories

HabitatuseIntroduction

size

Pathogen Disease

Fish

Species susceptibility

Age

Environment

Temperature

Virulence

Dose

Size

Goals of Risk Assessment Goals of Risk Assessment WorkgroupWorkgroup

• To complete the risk assessment exercise begun To complete the risk assessment exercise begun at the 2003 WDSat the 2003 WDS

• Develop examples of how a risk assessment Develop examples of how a risk assessment exercise can be usedexercise can be used

• Publish a manuscript on a RA model for Publish a manuscript on a RA model for whirling disease in Fisherieswhirling disease in Fisheries

• Make model accessible by providing to Make model accessible by providing to National Partnership for further disseminationNational Partnership for further dissemination