African swine fever in wild boar: ecology and biosecurity

Introduction. In 2007, African swine fever (ASF) was discovered in the Caucasus, and has now spread to several countries in eastern and northern Europe. By 2018, the ASF crisis had expanded to Asia, where the virus continues to spread. The large-scale epidemic travelled thousands of kilometres from its point of detection in Georgia and, in addition to its endemic establishment in domestic pigs, the disease eventually invaded populations of wild boar. In Europe, from 2014 to 2015, the circulation of this virus in natural ecosystems developed into a self-sustained epidemiological cycle. Currently, the disease is endemic in wild boar populations in several countries and continues to expand its range in Europe, a cause for very serious concern. The situation in parts of Asia is likely to follow the European trajectory, not only with the involvement of wild or feral pigs belonging to the species Sus scrofa, but also with other wild suids. Controlling this sylvatic epidemic is a challenging task for veterinary authorities, given the complexity of the disease epidemiology, a lack of previous experience, the unprecedented geographical scope of the problem, and its transboundary and multisectora l nature.This document was prepared following the recommendations of the Standing Group of Experts on African Swine Fever in the Baltic and Eastern Europe sbregion. The group was set up under the umbrella of the Global Framework for the Progressive Control of Transboundary Animal Diseases (GF-TADs) to build closer cooperation between countries affected by ASF, fostering a more collaborative and harmonized approach to the disease across the Baltic and Eastern Europe subregion. At the eighth meeting of the Standing Group of Experts on African Swine Fever in Chisinau, Moldova, on 20 and 21 September 2017, the World Organisation for Animal Health (WOAH), the Food and Agriculture Organization of the United Nations (FAO) and the European Union decided to cooperate in the preparation of a technical, but also practically useful, document containing a compendium of essential information about hunting management, biosecurity and wild boar carcass disposal. More recently, reflecting the continuing threat posed by ASF, the evolution of the crisis, and scientists’ and authorities’ understandings of how to manage it, it was felt that a new edition would make an important contribution to the situation. This document provides an evidence-based overview of ASF ecology in the northern and eastern European populations of wild boar. It briefly describes a range of practical management and biosecurity measures or interventions, which can help stakeholders in the countries experiencing large-scale epidemics of this disease to address the problem in a more coherent, collaborative and comprehensive way. The publication should not be viewed as an authoritative manual providing ready-made solutions on how to eradicate ASF from wild boar. The facts, observations and approaches described in the document are presented with the intention of broadly informing veterinary authorities, wildlife conservation bodies, hunting communities, farmers and the general public about the complexity of this novel disease, and the need to plan wisely and carefully coordinate any efforts aimed at its prevention and control. In order to reduce risks and prevent the negative implications of the now widespread presence of ASF in the ecosystems of northern and eastern Europe, close and continuous cross-sectoral collaboration is essential. Veterinary authorities, forestry and wildlife management agencies and nature conservation and hunting bodies, organizations, communities and clubs should be mutually informed of different aspects of the problem, which sometimes go well beyond their immediate competencies and conventional responsibilities. Therefore, the focal target audience of the publication includes a broad range of potential readers, whose decisions or actions on national or local scales can contribute to controlling ASF in wild boar and mitigating the negative implications of this devastating disease for agriculture, as well as for the forestry and game management and nature conservation sectors. The geographical scope and most of the information or examples provided in this document are intentionally limited to the countries of northern and eastern Europe. These countries share similar environments, agroecological and wildlife management systems, and have experienced the same sylvatic transmission cycle of ASF, which emerged a few years ago. As the epidemiological situation in Europe remains dynamic, and the knowledge on ASF epidemiology in wild boar is far from complete, the document will require future revision and updates in order to reflect new findings, experiences and lessons to learn. This is particularly relevant regarding the ongoing evolution of the global situation and spread of the disease into tropical countries, where its epidemiological profile in new environments may significantly differ from what has so far been seen in European contexts. The publication consists of seven chapters. Chapter 1 describes the epidemiological cycle of ASF in wild boar as it is currently perceived by expert and research communities. It details the main risk factors related to the circulation of the virus in the ecosystems of northern and eastern Europe. Chapters 2 and 3 briefly reflect on questions and issues (some of which are controversial) that are typically raised and debated in relation to wild boar biology and population management in the context of ASF control. Chapters 4 and 5 provide a detailed description of the key elements of biosecurity strategy recommended at the level of hunting grounds, and its practical implementation, based on the experiences of countries in northern and eastern Europe affected by the ongoing sylvatic epidemic of ASF. Chapter 7 concerns data collection, stressing the need for continuous systematic efforts to better document field observations in order to improve our understanding of disease epidemiology as it evolves and expands its geographic range. Finally, the document addresses risk communication strategies and approaches, which are crucial for effective cross-sectoral collaboration among stakeholders dealing with such a complex problem as the spread of ASF in wild boar. Each chapter opens with a short paragraph briefly introducing its contents and concludes with a summary of the key messages.