Discussion on a Selection of Key Scientific Articles

By John Atkinson,
Associate Director, Intergovernmental Veterinary Health
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Using multi-criteria risk ranking methodology to select case studies for a generic risk assessment framework for exotic disease incursion and spread through Europe Horigan, V., De Nardi, M., Simons, R. R. L., Bertolini, S., Crescio, M., Estrada-Peña, A., Léger, A., Maurella, C., Ru, G., Schupper, M., Stärk, K.D.C., Adkin, A. Preventative Veterinary Medicine. 2018;153:47–55.

Key Thoughts:
Exotic diseases pose an ongoing threat to our animals that must not be ignored. With so many endemic diseases to contend with, it is tempting to think of exotic diseases as being far away and not relevant. However, waiting until they are upon us is too late and the cost of dealing with outbreaks is higher than taking a preventative approach. As this paper shows, pathogens can be ranked in many different ways depending on the model chosen and objectives of the exercise.  Selecting the right criteria and weighting in order to get the most useful results for the situation concerned is crucial, and there will often be multiple priority diseases. Whichever diseases are prioritised, it is important to communicate clearly to animal owners about the risks, the need to be vigilant, and the importance of rapid reporting.

Article Summary:
Countries are at risk of outbreaks of exotic diseases in their animal populations which can have a huge impact on animal health and welfare, human health, trade, and productivity. As resources for exotic disease prevention are limited, they should be targeted to those diseases which have both the highest impact and are most likely to occur. Exotic disease pathogens can be prioritised using risk ranking tools, but no one tool fits all.

This work aimed to develop and apply a multi-criteria ranking model to pathogens threatening Europe’s animals. From an initial list of 66 global and European notifiable diseases, 33 animal health pathogens that are not normally found in the European Union were selected and defined as ‘exotic’. Each of these were assessed according to how likely they are to be transmitted by nine key pathogen transmission pathways or routes. The pathogens were scored against six criteria selected and weighted by animal health experts. The impact of the decisions made in deriving these scores was investigated using various scenarios and statistical analysis undertaken to compare levels of agreement among the animal health experts. The 10 highest ranking pathogens were then used to select case studies for a generic risk assessment to explore exotic disease introduction and transmission within Europe.

From the 33 pathogens selected, avian influenza (highly and low pathogenic) and Newcastle disease were the top three rated diseases from the risk ranking exercise. These diseases together with bluetongue then topped the rankings in all the scenarios. There was a high level of agreement among the animal health experts overall, with some variation for specific criteria possibly reflecting the relative risks in their own countries.

From the top 10 highest ranking pathogens that were assessed for case study selection, bluetongue, classical rabies, and classical swine fever were selected.  Some diseases were not selected because considerable research is already being conducted (avian influenza) and because of a lack of interest from funding bodies (Newcastle disease). Others were not selected because they shared transmission routes or pathways, so the highest ranking disease was chosen. Classical swine fever was chosen ahead of African swine fever because of the availability of data.

A web-based tool has been developed to adjust the criteria and weightings for the framework as required. Additionally, the focus here was on the risk of incursion and impact of trade, compared to the DISCONTOOLS prioritisation model which focuses on research needs to fill gaps regarding diagnostic tests and vaccines, in particular. The authors noted that it was of interest that African swine fever, foot-and-mouth disease, and Rift Valley fever ranked highly using both methods. 

Implementation of a regional training program on African swine fever as part of the cooperative biological engagement program across the Caucasus region De Nardi, M., Léger, A., Stepanyan, T., Khachatryan, B., Karibayev, T., Sytnik, I., Tyulegenov, S., Akhmetova, A., Nychyk, S., Sytiuk, M., Nevolko, O., Datsenko, R., Chaligava, T., Avaliani, L., Parkadze, O., Ninidze, L., Kartskhia, N., Napetvaridze, T., Asanishvili, Z., Khelaia, D., Menteshashvili, I., Zadayan, M., Niazyan, L., Mykhaylovska, N., Brooks, B. R., Zhumabayeva, G., Satabayeva, S., Metreveli, M., Gallagher, T., Obiso, R. Frontiers in Veterinary Science. 2017;4:164. Doi: 10.3389/fvets.2017.001664

Key Thoughts:
It is essential that awareness of transboundary and emerging diseases, such as African swine fever, is raised across all the relevant stakeholders. To achieve this, a general approach can be developed through collaboration and then adapted for use in individual countries. Each stakeholder or target group must be accurately identified and the best means of engaging with them established. Different approaches may be needed for different groups; such tailoring of communication and training materials will increase engagement and, in turn, increase the chances of success. Whilst some people may be hard to reach, or even resist the recommendations for disease prevention, it is important that all key groups within countries and regions are involved because these diseases cross boundaries and borders affecting many different populations.

Article Summary:
African swine fever (ASF) is a highly infectious, lethal, viral disease of domestic and wild pigs. It spreads through direct animal contact, ingestion of contaminated meat, and soft tick vectors, and is one of the most serious transboundary diseases of pigs. ASF was first identified in the Caucasus in 2007 and has since spread in the region and beyond.

A training program was developed by the US Defense Threat Reduction Agency in collaboration with the governments of Armenia, Georgia, Kazakhstan, and Ukraine, each of which have important pork industries and are at risk of future ASF outbreaks.

The aim was to raise public awareness of ASF in order to reduce the disease risk and its associated impact. Cross-border collaboration was required to collectively develop a training program which could be administered in each of the countries.

Topics were addressed through regional meetings, in-country independent workshops, and in-country outreach classes. People throughout the pig production chain were identified so they could be taught to recognise, prevent, report, and respond to suspected ASF cases so that any outbreak could be swiftly controlled. Information was shared among country representatives and analyses were undertaken to identify limitations in the educational activities and materials pre-existing in each country. Materials were revised, communication toolkits developed for each country relevant to their target groups and objectives, and implementation plans created.

Seventeen trainers were trained from the Ministries of Agriculture across the four countries, who then trained the target groups in each country, such as veterinarians, farmers, and hunters. The program success was evaluated on the ability of the trainers to conduct the public outreach program and share ASF information. A total of 13,862 people from the target groups were trained, and 123,098 training materials distributed.

ASF knowledge was determined to have generally increased, but some limitations were highlighted. Improving the engagement of hunters is needed to increase wild boar carcass reporting. Backyard pig farmers also need to be more engaged because there is currently little incentive and few resources for them to improve biosecurity. In addition, some farmers were distrustful of veterinary authorities, and so reluctant to follow their recommendations. Educational materials should be more tailored to target groups, and other influential groups should be involved in the future alongside veterinarians.

A general approach for conducting and deploying a public outreach program was established which can be applied to other diseases of public concern in the future.



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