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Risk-Based Animal Disease Surveillance
Enhancing surveillance system performance
by Koen Mintiens and Francisco J. Zagmutt, Vose Consulting
Introduction
Emerging animal diseases, particularly those harmful to humans (zoonoses) can cause considerable economic and social upheaval. Epidemics of bovine spongiform encephalopathy, classical swine fever, foot and mouth diseases, avian influenza and bluetongue, which occurred in Europe during the last decades are clear illustrations of this trend. Moreover, the 2003 epidemic of avian influenza in the Netherlands not only had an economical impact but also represented a considerable hazard to public health as a potential zoonosis. Emerging diseases are those that appear in a population for the first time, or that may have existed previously at a very low level but are rapidly increasing in incidence or geographic range. Globalization and climate changes have increased the risk for emergence of animal diseases such as African horse sickness or epizootic hemorrhagic disease, and zoonoses like West Nile virus or Rift Valley fever.
The growth in volume and diversity of international trade in animals and animal products has increased the demand by competent authorities for improved veterinary surveillance systems. But many events may cause surveillance systems failure. Taking these risk-events into consideration when developing and implementing surveillance protocols will lead to more efficient and accurate surveillance systems. In this whitepaper we outline the risk for failures that can be encountered when implementing veterinary surveillance programs and we propose different aspects of risk-based surveillance which can contribute to successful animal disease surveillance systems.
Surveillance systems
Surveillance, in origin a French word dating from the Napoleonic wars, was originally referring to the ‘observation of potential subversive people’. In animal health care, surveillance relates to observing animal populations in order to provide information on health and disease and their determinants. This information should allow decision-makers to take disease control measures if deemed necessary. Essentially, surveillance systems can serve three purposes: 1) early-detection of a novel introduction; 2) estimating the evolution of the prevalence; or 3) substantiating absence of a disease in a population. Each purpose requires different surveillance protocols. For example, early-detection of a novel disease introduction requires strict repeated observations with a frequency that takes the introduction probability into account. On the other hand, freedom from disease can only be substantiated when the probability for disease introduction is extremely small.
Risk for surveillance failures
Some of the major factors that can cause surveillance systems failure are listed below.
- Uncertain diagnostic tests
- Observing the unknown
- Uncertain disease dynamics
- Non-compliance to the protocols
If you have found the information above useful and would like to read the entire whitepaper, please complete the form below and the full paper will be emailed to you.
If you have any questions or comments about this whitepaper or would like to discuss Risk-Based Animal Disease Surveillance consulting or training, please contact us by email (info@voseconsulting.com) or phone (303-440-8524).
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