HPAI Risk Assessment and ManagementDirk Pfeiffer and Joachim Otte

Pro-Poor HPAI Risk Management ProjectInception Workshop, Chiang Mai, 12.12.07

Objectives

to develop qualitative and quantitative risk assessment models capturing introduction and spatial and temporal spread of HPAI through different vectors and/or anthropogenic processesto assess, ex-post and ex-ante, the effectiveness of risk mitigation measures

Reservoirs Dead-endhosts

Spillover / Reservoir ?

GENE POOL

adapted from V. Martin, FAO-AGA

Risk Analysis Components(after OIE Animal Health Code)

Hazard Identification

Risk Assessment

Risk Management

Risk Communication

ExposureAssessment

ReleaseAssessment

ConsequenceAssessment

Research Questions

potential pathways through which H5N1 HPAI virus can spread to and within poultry populationslikelihood of entry of H5N1 HPAI viruslikelihood of exposure of domestic poultry populations to H5N1 HPAI virus

Research Questions cont.

likelihood of H5N1 HPAI virus becoming endemic in selected epidemiological strata and what is level of infection if this occurslikely impact of different control options on risk of H5N1 HPAI virus being transmitted in epidemic and endemic infection scenarios

H5N1 HPAIV Release Assessment for EU

Contaminatedfomites

Tissue tropism/ viruslevels, processing &

products

Stoppingplaces

within EU

Numbers

Origin

Species

Duration of transit

EU Border

Assessing the probability of viable virus entering EU= Release assessment

Inside EU

Avianproducts

legallyimported

Wildmigratory

birds

Live birdsand hatchingeggs legally

imported

Live birdsand hatchingeggs illegally

imported

Avianproductsillegally

imported

Route

Legalsafeguards

at origin

Legalsafeguards

at EU border

Origin, species

Legalsafeguards

at origin

Duration &conditions of transit

Origin, species

Legalsafeguards

at EU border

Numbers Numbers/quantity

Origin

Type offomite

Contactat origin

Duration &conditions of transit

Viral fragility

Any safeguards/potential

safeguards?

Numbers of fomites

from EFSA 2006

H5N1 HPAIV Exposure Assessment for EU

Contaminatedfomites; e.gpackaging,

tyres, shoesetc.

EU Border EU Border

Importedavian

products(legal &Illegal)

Wildmigratory

birds

Freeflying

Crossed EU border; inside EU

Hunted

Hatchery

Domesticflock

Releaseto wild

Zoo/collection

Slaughter

Fly-tipping

Carcasescraps

Importedlive birds(legal &Illegal) Quarantine

Importedhatching

eggs (legal& Illegal)

Scraps/effluent

Nooutsideaccess

Outsideaccess

EU wildbirds

EU domesticbirds: outside

access

EU domesticbirds: no outside

access

Landfill

Swill feedPoor bio-security

from EFSA 2006

9

Simulation of H5N1 HPAI Spread

by Ferguson et al, Imperial College

neighbourhood spread

movement spread

Temporal Pattern of HPAI Outbreaks in Viet Nam

10

0

50

100

150

200

250

300

Jan

Feb

Mar

Apr

May Jun

Jul

Aug

Sep Oct

Nov

Dec Jan

Feb

Mar

Apr

May Jun

Jul

Aug

Sep Oct

Nov

Dec Jan

Feb

Mar

Dai

ly n

o. o

utbr

eaks

Tet holiday Feb 9-11, 2004

Tet holiday Feb 11-13, 2005

Tet holiday Jan 29-31,

2006

2004 2005 2006

Vaccination Campaign

Poultry Flows in North Viet NamPoultry Farmers

Itinerant Village Traders (farmgate)

Retailers

Wholesalers

Local/Community Market

Neighbors/Villagers (farmgate)

47% 15%38%

(64%)

CONSUMERS

(18%)(18%)

73% 27%

(19%)

(54%)

(27%)

Other intermediaries

93%

7%

Social Network Analysis of Poultry Trade around Hanoi

Pajek

Commune Trader

♦

From Magalhaes, Ortiz Pelaez et al: In preparation

2003-4 Epidemic Wave in Southern Viet Nam

13

Prediction

“Reality”

from Pfeiffer et al 2007

provided by V. Martin, FAO-AGA14

Probability of H5N1 Presence

from Gilbert et al – under review

Potential Control Measures

Vaccination (blanket, strategic)‘Bio-security’Compartmentalization, zoningEnhanced disease detection and response

o Cull (radius?)o Compensation, ‘assistance’

‘Sanitization’ of markets and marketing

H5N1 HPAIV Farm Transmission Model for Viet Nam

Magalhaes et al. 2006

Example Simulation Output: Impact of Vaccination in Sector 4

04 050,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7Farm/da

Incidence rate_D3

Incidence rate_C3

Incidence rate_S4

Magalhaes et al. 2006

Envisaged Project Outputs

risk pathway diagrams specific to local circumstances and epidemiological strata developed in consultation with stakeholdersqualitative or quantitative risk assessment modelsrobust (mathematical) models of dynamics of H5N1 HPAI virus infection specific to study countriesestimates of the effectiveness of different control interventions under field conditions

Local Risk Assessment Teams

national partners responsible for informing decision makers to work in close collaboration with members of project teamsrisk assessment models to be developed by local epidemiologists or local mathematical modellersmulti-disciplinary teams to assure that risk assessment is linked to risk management options being considered

Required Skill Sets

Avian influenza epidemiologyAnimal disease managementPoultry productionExpert opinion elicitation/participatory epidemiologyRisk assessmentMathematical disease modellingEconomists

Summary

structured, multi-disciplinary approach o qualitative and/or quantitative

science-based and transparento documentation of evidenceo engagement with stakeholders

express and communicate risk as well as uncertainty surrounding the estimate!!!