22 ISSN 1810-1119 [print] ISSN 2070-2493 [online] African swine fever in wild boar ecology and biosecurity African swine fever in wild boar ecology and biosecurity FAO ANIMAL PRODUCTION AND HEALTH / MANUAL 22 FAO ANIMAL PRODUCTION AND HEALTH / MANUAL 22 African swine fever in wild boar ecology and biosecurity Authors Vittorio Guberti Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Italy Sergei Khomenko Disease Ecologist and Geographic Information System (GIS) Expert, Food and Agriculture Organization of the United Nations (FAO) Marius Masiulis Head of Emergency Response Department, State Food and Veterinary Service of Lithuania and Lecturer in the Veterinary Academy of the Lithuanian University of Health Sciences Suzanne Kerba Risk Communications Consultant, Paris, France Published by the Food and Agriculture Organization of the United Nations and the World Organisation for Animal Health and European Commission Rome, 2019 Required citation: Guberti, V., Khomenko, S., Masiulis, M. & Kerba S. 2019. 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Photo cover: ©Adriano De Faveri (ISPRA) iii Contents Foreword vii Acknowledgements viii Acronyms ix Introduction 1 Epidemiology of African swine fever in wild boar populations 3 Epidemiological cycles and geographical distribution of ASF in Europe 3 Characteristics of the ASFV circulating in Eurasia 7 Environmental resistance 7 Infection routes and mechanisms involved 10 Direct horizontal transmission 10 Local indirect transmission through contaminated environment 10 Long-distance indirect transmission involving humans 11 Transmission chain in wild boar populations 12 ASF dynamics and wild boar population density 15 Key messages 19 Some aspects of wild boar biology and demography relevant to the control of African swine fever 21 Why wild boar distribution changes 21 Can we measure wild boar numbers reliably? 22 How many wild boars are “too many”? 24 Why do wild boar populations increase everywhere in Europe? 25 How supplementary feeding affects populations of wild boars 26 How supplementary feeding interferes with control of ASF 28 Why hunters need to revise wild boar population management systems 31 Key messages 32 Approaches to wild boar population management in the areas affected by African swine fever 33 Can eradication of wild boars be a solution? 33 Why conventional hunting fails to level wild boar population growth 35 Is population control of wild boars a panacea for ASF eradication? 35 Review of approaches to wild boar population management in an infected area 36 Non-lethal methods involving movement restriction 37 iv Non-lethal methods with impact on population demography 38 Management approach through a ban on both hunting and feeding of wild boars 41 Lethal methods involving reduction of the population 42 Key messages 46 Biosecurity in affected forests 49 ASF detection in free areas 49 Detection of carcasses of dead wild boars 49 Precautionary measures 51 Carcass disposal 54 Carcasses might be delivered to a rendering plant or incinerator, burnt or buried on the spot 55 Containers 56 Burning on the spot 56 Indirect contamination of the habitat with the ASFV 59 Key messages 60 Biosecurity during hunting 61 ASF detection in free areas 61 Management plan for wild boar hunting 63 The hunting ground biosecurity plan minimizes the probability that the virus will spread outside the infected area through hunting activities 63 Wild boar transport from the hunting spot to the dressing facility 63 Requirements and equipment for the dressing area/facilities 64 Proper disposal of offal 66 Safe onsite storage of hunted wild boars until tested ASF-negative 66 Procedures for the disposal of ASFV-positive wild boar and for cleaning and disinfecting facilities 67 Disinfectants recommended for African swine fever virus 67 Key messages 70 Data collection 71 Wild boar data accompanying samples 71 Standardized age classes 71 Fecundity 73 Fertility 73 Standardized dating of carcasses (rate of carcass decomposition) 73 Key messages 76 v Effective communications between veterinary services and hunters 77 Building strong communications messages to hunters 78 Two-way communications 79 Choosing communications channels 81 Risk communications and stigma 81 Key messages 82 Bibliography 83 Annex. Experience of controlling localized outbreaks of ASF in wild boar populations in Czechia and Belgium 91 vii Foreword African swine fever (ASF) is a devastating hemorrhagic viral disease of pigs, affecting domestic and wild pigs of all ages and sexes. The disease is the cause of major economic losses, threatens food security and safe trade, and challenges sustained swine production in affected countries. Since ASF emergence in Georgia in 2007, the disease has spread to many countries in Europe and in 2018 was detected in East Asia, where over 60 percent of global domestic pig inventories are found. The spread of the African swine virus genotype II into the Eurasiatic wild pig population was unprecedented; the increased densities in wild pig that had taken place in eastern and central Europe over the past few decades was a prime environment for the ASF virus to expand its geographical distributional range. Climate change and extensive cereal produc- tion enhanced local wild pig densities and expanded their geographical distribution. Besides these general tendencies, hunting management boosted wildlife abundance by curbing the hunting of wild sows thereby maintaining or increasing the local reproductive stock. They created winter feeding areas aimed at preventing the once-typical demographic crashes of the wild pig populations due to scarce food availability determined by the forest tree seed (mast) cycles. These areas promoted higher fecundity and fertility parameters. As a result, in most of Eurasia, wild pig management practices have artificially increased both abundance and geographical distribution of wild boars by bypassing the natural carrying capacity of the environment. ASF spread progressively within China in the second part of 2018 with transboundary spread in early 2019 to Mongolia, Viet Nam and Cambodia. Similar to the epidemiological situation in wild swine in Europe there is a heightened risk for ASF endemicity in East and Southeast Asia and further progressive global spread with unpredictable consequences.The control of ASF when wild pig populations are involved in the transmission and maintenance cycle represents an additional challenge for the veterinary and wildlife authorities, given the added complexity in disease epidemiology, lack of previous experience, the unprecedented geographical scope of the problem, and its transboundary and multi-sectoral nature.