Estimating economic cost of zoonotic disease

The One Health economic framework (adapted from Narrod et al. 2012) is a modified risk analysis which links outputs associated with animal health transmission models, economic impact models and risk analysis to inform the planning of investments through the most promising interventions or set of interventions and improve economic outcomes such as poverty alleviation, food security and improved livelihoods.

This framework allows for identification of potentially useful types of analysis to inform decision makers prior to intervention implementation. This is valuable as decision makers evaluate different mitigation techniques to obtain a desired level of safety at a given cost. At best, mitigation is negotiated with all stakeholders, communities, authorities and scientists in participatory transdisciplinary processes. Risk managers can choose strategies depending on the risk preferences for affected stakeholders and comparative advantages in implementing risk-reduction options. It is difficult to compare strategies which consider risk reductions with others evaluating costs and benefits. Despite good intentions, decisions can lead to losses in social welfare through unexpected outcomes and consequences. Decision makers are aided by a framework which structures complex information and accounts for implications of the intricacy.

The approach is similar to a traditional risk assessment, which includes a release assessment (where all potential pathways for disease introduction are identified), an exposure assessment (in which all potential pathways for exposure to the zoonotic disease in animals and humans are identified) and a consequence assessment. It is similar because it also involves analysis to evaluate risk management efforts in terms of benefit costs and cost/effectiveness. A modification is that analyses enabling decision makers to consider stakeholder behaviour modifiers, such as knowledge, attitude, and perception analysis or willingness to pay/adoption analysis, are also included. Additionally considered is an analysis enabling decision makers to understand factors affecting intervention uptake to assess successful strategies.

A stepwise approach is utilised:

1. Estimate the extent of the disease and potential spread;
2. Estimate the cost of zoonotic disease on livelihoods outcomes (income, health, trade), including environmental impacts;
3. Assess the cost-effectiveness of risk management strategies currently employed for reduction of human and animal zoonotic disease exposure risk;
4. Identify factors affecting adoption of zoonotic risk reduction strategies in poor households, the commercial sector and government bodies.

At all steps, participatory stakeholder consultations can take place which will ascertain perceived risk and mitigation priorities between all involved stakeholders. Each proposed analytical approach has associated resource issues, and it is not necessary to perform all simultaneously. Assembling the framework ensures that the analyses are integrated from the outset providing maximum benefit. Outputs of analytical efforts within the proposed framework will enable decision makers to evaluate the cost-effectiveness of various control measures and potential combinations for risk reduction from different perspectives.

Calvin Schwabe’s ‘One Medicine’ concept has become more prominent in the last decade. The modified risk analysis approach described here correlates but has evolved towards One Health conceptual thinking while emphasising epidemiology and public health. Acceptance is reflected through adherence by professional organisations, governmental establishment of joint public and animal health working groups and inception of numerous research and surveillance programs.

The framework for estimating the societal cost of zoonoses is an open tool, translating the One Health concept into practical methodology. It is consistent with the ‘One world one health’ strategy, first defined in 2008, and currently adopted by the World Bank. The proposed framework is envisioned as a springboard for discussion, resulting in mutually adopted practical cooperation between human and animal health with a unique emphasis on developing countries as well as global applicability.

References

Narrod, C. et al. (2012). A One Health Framework for Estimating the Economic Costs of Zoonotic Diseases on Society, in: Ecohealth 9(2), 150–162.