Framing the Problem of Emerging Zoonotic 
Disease Risk Using a One Health Approach 
Hung Nguyen-Viet, Dominic Travis, Dirk Pfeiffer, Suwit Chotinun, Jakob 
Zinsstag, Delia Grace, Boripat Siriaroonrat, Bruce Wilcox 
Content 
 Conventional risk assessment 
 Issues of risk assessment applied for EZDs 
 Adjusted risk assessment framework based 
on integrative methods 
 Conclusion 
Integrative Approach 
• Integrative research approaches (One Health, Ecohealth) 
are believed to be more effective for tackling the 
complexity associated with emerging infectious diseases 
than a single- or multi- disciplinary approach. 
 
• Risk-based approaches have been widely used in 
environmental health and epidemiology to identify critical 
points where hazards can be controlled and hence risks 
to human health reduced.  
 
• Risk assessment: effective science-based tool for 
informing decision-making 
Hazard vs. Risk 
Hazard: A biological, chemical or physical agent or condition 
with the potential to cause an adverse health effect (Codex 
Alimentarius 1999) 
 
 
 
Risk : likelihood of identified hazards causing harm in 
exposed populations in a specified time frame including the 
severity of the consequences. 
RISK = Chance*Hazard*Exposure*Consequence 
Risk 
assessment 
Risk 
management 
 
Decision 
Risk 
Communication 
 
Risk analysis 
Risk analysis: describes how risks are dealt with 
within the society 
 
• Risk communication: 
Communication of risks to managers, stakeholders, public 
officials, and the public. 
• Risk management:  
How to manage the problem? 
 
• Risk assessment (RA): 
Is there a problem and how severe the 
problem is ? 
Source: Codex (1999) 
“Risk” development 
1924  
OIE 
1940s 
PSA  
1950s 
ADI 
1960s 
PRA 
1994  
SPS 
1962 
CODEX 
1959 
HACCP 
1983 
NAS 
1945 
FAO 
1948 
WHO 
1970s 
QRA 
1990s 
MRA 
2001 
OIE-FS 
2000s 
Bioterrorism
. 
1980s 
PbRA 
Grace (2011) 
Application of Risk Assessment 
• International standard risk assessment 
frameworks: OIE/IUCN, Codex Alimentarius  
• Import risk assessment  
• Food safety risk assessment for animal source 
foods  
• Ecological risk assessment 
• Natural disaster risk assessment 
• (finances, banking…) 
Codex Alimentarius risk assessment 
framework 
Risk  
Communication 
Risk  
Management 
Risk  
Assessment 
Hazard  
identification  
Exposure  
assessment  
Hazard  
characterization  
Risk 
 characterization 
OIE/IUCN 
 Import risk 
assessment 
Release  
assessment 
Exposure 
 assessment 
Consequence 
 assessment 
Risk  
assessment 
Risk  
management 
Risk  
assessment 
Hazard  
identification 
                         Risk communication                       
Full Process 
• Question formulation  
• Hazard ID 
– Establish criteria 
• Draw a picture 
– Identify critical control points 
• Develop a model 
– ID and evaluate data sources 
– Input data (from monitoring or surveillance efforts) 
• Run model 
• Assess results and effects of data quality 
– Sensitivity analysis and uncertainty 
• Collect more data 
• Rerun model 
 
Issues of current risk assessment 
• Conventional risk-based approaches applied to emerging 
infectious diseases: limitations. 
• Many possible determinants and factors operating at different 
spatial and temporal scales 
• Uncertainties resulting from both the lack of data and 
unpredictability of the dynamics involved in the disease 
emergence process 
• Lack of resources to carry out risk assessment 
• Specific and complex for public and policy makers 
• Disconnection with reality 
Emerging Infectious Diseases Research “Blue Print” 
Wilcox and Colwell (2005) 
Disease Emergence Multiple Causal Factors and Mechanisms 
adapted from  Daszak et al – Science - 2000 
How to improve the current 
conventional risk assessment 
approach? 
Adjusted risk assessment 
• Assessment of ecosystem vulnerability and 
resilience as a component of risk 
assessment.  
 
Hazard  
identification  
Exposure  
assessment  
Hazard  
characterization  
Risk 
 characterization 
Adjusted risk assessment 
• Assessment of ecosystem vulnerability and 
resilience as a component of risk assessment.  
• Risk assessment becomes interactive: 
– categorizing and ranking hazards, vulnerable, 
population, and ecosystems 
– prioritizing risk issue in terms of funding, politic driven- 
versus reality and societal needs using participation.  
• Consider hazard, risk and risk drivers from 
different perspectives including social aspect and 
perception 
Risk  
Assessment 
Risk 
 Management  
Risk  
Communication 
Participatory methods 
Participatory Risk Analysis 
(for food safety risk analysis in informal marketing system) 
Concept of participatory risk analysis 
Grace et al (2011) Revue Africaine de Santé et de Productions Animales. 
Conclusions and ways forward 
• Risk assessment: effective science-based tool for 
informing decision-making but represent limitations to 
EZDs 
 
• Need more integrative aspects and participation in risk  
assessment involving an ecosystem  perspective 
(vulnerability and resilience of ecosystem, social, 
perrception…) 
Thank you! 
 
Emerging Pandemic Threats Program 
   PREDICT • RESPOND • PREVENT • IDENTIFY