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!!!