A review of different methods to find and date wild boar carcasses in different countries

A review of different methods to find and date wild boar carcasses in different countries Enetwild Consortium1, Vada R.2, Broz L.³, Citterio C.⁴, Obber F.⁴ Ferroglio E.2, Gómez M. A.5, Hahn N.⁶, Knauf S.⁷, Kreutzer M.8, O'Mahony K.³, Platovšek Z.10, Pokorny B.10, Sauter-Louis C.⁷, Staubach C.8,9, Campana S.5, Arseni M.5, Zanet S.2, Vicente J5. 1https://enetwild.com/, ²Università di Torino, Italy; ³Czech Academy of Sciences, Czech Republic; ⁴Istituto Zooprofilattico Sperimentale delle Venezie, Italy; ⁵Universidad de CastillaLa Mancha, Spain; ⁶WILCON-Wildlife Consulting, Gomadingen, Germany; ⁷Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald - Insel Riems, Germany. 8Institute of International Animal Health/One Health, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald - Insel Riems, Germany; 9Professorship for One Health/International Animal Health, Faculty of Veterinary Medicine, Justus Liebig University, Giessen, Germany; 10Faculty of Environmental Protection, University of Primorska, Slovenia Reference: OC/EFSA/BIOHAW/2022/01 Subject: Wildlife and One Health: wildlife disease management, surveillance, wild boar carcass, forensic dating, African swine fever, early detection, freedom of disease Subcontract 013 Abstract The detection, removal and disposal of wild boar carcasses in areas affected by African Swine Fever (ASF) is key to understanding disease persistence and improving the effective management of risk. This report reviews different methods of finding and dating wild boar carcasses, considering the factors that affect their effectiveness and practical application in the field. We assessed these issues based on peer-reviewed scientific literature, gray literature, and interviews with government agencies and wildlife professionals in organisations and networks across Europe. Two decades after the introduction of African Swine Fever Virus genotype II in Europe, systematic descriptions of the best methods, available protocols, or detailed guidance remain limited. However, relevant research has recently been conducted in Central Europe addressing the two evaluated issues. Carcass search methods can be broadly categorized into four main types: (i) targeted patrols in areas likely to host wild boar carcasses; (ii) systematic grid searches of a defined area; (iii) the use of detection dogs; and (iv) drone-assisted searches. In our sample, the latter three methods were the most frequently employed, with similar levels of representation. Among the relevant sources identified for assessing carcass dating methods, 36% were based on experimental and controlled studies, while the remainder relied on observational data with limited or no experimental control. Most sources adapted previously published methodologies focused on the direct morphological assessment of the decomposition process, typically providing a stage-based classification of carcass decay rather than a precise temporal estimate. Direct carcass observation was employed either alone or in combination with additional approaches such as camera trapping, metabolomics, entomology, and histological Review: methods to find and date wild boar carcasses 2 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). analysis. Field trials are needed to test the effectiveness of carcass searches and the precision of carcass dating, as well as to adapt and validate methodologies in different European contexts. This review of various carcass detection and dating methods highlights the diversity of approaches used in different countries, emphasising the preliminary nature of the research and the need for further investigation and field trials. Key words: ASF management, surveillance, wild boar carcass, forensic dating, early detection, freedom of disease Correspondence: bi[email protected]opa.eu Disclaimer: The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the authors in the context of a contract between the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. Acknowledgements:. Suggested citation: Enetwild Consortium, Vada R., Broz L., Citterio C., Obber F. Ferroglio E., Gómez M. A., Hahn N., Knauf S., Kreutzer M., O'Mahony K., Platovšek Z., Pokorny B., SauterLouis C., Staubach C, Campana S, Arseni M., Zanet S., Vicente J., 2025. A review of different methods to find and date wild boar carcasses in different countries. EFSA supporting publication 2025. 86 pp. 86. 10.5281/zenodo.17591492 ISSN: 2397-8325 © European Food Safety Authority, 2025 Reproduction is authorised provided the source is acknowledged. Review: methods to find and date wild boar carcasses 3 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Table of Contents Abstract ....................................................................................................................... 1 Summary ..................................................................................................................... 4 1. Introduction ......................................................................................................... 10 2. Background and Terms of Reference ....................................................................... 15 3. Methods .............................................................................................................. 17 4. Results ................................................................................................................ 28 4.1. Wild boar carcass search .................................................................................... 28 4.2. Wild boar carcass dating ..................................................................................... 50 4.2.1. Available data ................................................................................................ 50 5. Discussion .............................................................................................................. 57 5.1. Wild boar carcass search ........................................................................................ 57 5.1.1 The relevance of systematic and rapid response ...................................................... 57 5.1.2 Current practices and knowledge gaps in carcass search methods ............................. 58 5.1.3 Carcass search strategies and key factors affecting efficiency ................................... 58 5.1.4 Carcass handling, biosecurity, and the need for early removal .................................. 62 5.1.5 Future research and experimental trials to improve search efficiency ......................... 63 5.2. Wild boar carcass dating ........................................................................................ 66 5.2.1 Overview of available studies and geographic distribution ........................................ 66 5.2.2 Methodological approaches ................................................................................... 67 5.2.3 Current knowledge gaps....................................................................................... 69 6. Conclusions ............................................................................................................. 70 6.1. Wild boar carcass search ........................................................................................ 70 6.2. Wild boar carcass dating ........................................................................................ 73 7. References ............................................................................................................. 75 Annexes ..................................................................................................................... 79 Annex 1. Carcass search final selection (n=60 papers*method) ........................................ 79 Annex 2. Carcass dating final selection (n=11) ................................................................ 84 Review: methods to find and date wild boar carcasses 4 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Summary Background In areas affected by African swine fever (ASF) in wild boar populations, wild boar carcasses represent a potential source of infection for other wild boars or domestic pigs that may come into contact with them. The presence of infected carcasses enables the ASF virus to persist even after the wild boar population has been reduced to very low numbers. Therefore, detecting and removing carcasses in ASF-affected areas is an essential strategy for reducing ASFV transmission. Additionally, detecting infected carcasses in new areas helps to define infected areas and follow outbreaks evolution. In areas affected by or at high risk of ASF, carcass dating is essential to quickly and accurately estimate the post-mortem interval (PMI). This provides insights into the potential date of ASF introduction and informs disease control strategies, such as determining the extent of restriction zones or claiming freedom from disease. However, there is a lack of systematic, practical guidance on how to implement the best possible strategies that can be transferred and adapted to specific scenarios in order to optimise the efficacy of carcass searches and the precision of carcass dating. Objectives This report aims to review different methods to find wild boar carcasses under different scenarios, and the methods to date those carcasses, considering different factors determining their efficacy and practical application in the field. Methods We conducted a review of indexed scientific and grey literature, as well as interviewing administrations and wildlife network professionals across Europe. The systematic literature review first involved creating search strings and defining inclusion and exclusion criteria. These were applied after the articles were screened by topic, title and abstract. The selected articles were then screened in full for further refinement. We also used the snowballing method to find additional papers by following citations from included papers. National veterinary and wildlife authorities were interviewed and requested grey literature/protocols (not available as indexed literature) on the two issues in question, as well as protocols from international networks of wildlife veterinarians (in the case of carcass dating). Data were extracted from the selected papers and interviews and entered into a database in order to describe and compare different approaches, and to list the main factors that need to be considered when defining the best possible methods and practical strategies for different scenarios. Results Wild boar carcass search: Overall, 95 documents and/or interviews/questionnaires were collected that potentially included relevant information on carcass search methods and protocols, their characterisation, and the factors that may impact the findability of such carcasses. Sixty of the 95 documents passed the inclusion filter and provided a description (more or less detailed) of the main methods used to search for wild boar carcasses: 1) prospective patrols in sites favourable for the presence of dead wild boars; 2) systematic combing of an area; 3) dog detection; and 4) the use of drones. Most of the items corresponded to indexed literature (n = 29) and interviews (n = 22), while grey literature (usually in the form of blogs, technical reports and unpublished presentations) and questionnaires were less well represented. Given the limited availability of data sources, a maximal inclusion approach was adopted, incorporating all sources deemed useful for addressing each specific question—whether originating from published literature, interviews, or grey literature—regardless of their type. As expected, the majority of items originated from ASF-affected European countries, namely Germany, Italy and Poland. Relevant information Review: methods to find and date wild boar carcasses 5 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). was also collected from outside Europe to a lesser extent, particularly from South Korea and other South-East Asian countries. These documents mostly referred to ASF-infected areas or their immediate surroundings (within 10 km), and to a lesser extent to ASF-free areas. In terms of spatial considerations, we found a similar number of items relating to focal outbreaks and large areas of ASF progression. The predominant selection criteria for the area in which to search for wild boar carcasses within the data sources were the likelihood of wild boar presence, proximity to risk (e.g. the border with other ASF-affected countries), and previous notification of wild boar mortality. The area covered per wild boar carcass detection event and per day varies according to the method used, ranging from 6 to 750 hectares, with a modal value of 100 hectares. Parameters to evaluate the performance of wild boar searches were rarely reported, and the methods used varied greatly, making it difficult to compare studies, experiences and methods. While an experimental study was able to compare the number of carcasses found with the number hidden, in real scenarios the number of carcasses is usually unknown. In some cases, numerical expectations were derived from models. In some cases, numerical expectations have been derived from theoretical models. Although performance estimates can be expressed relative to the wild boar population, these population estimates may be unreliable and do not account for local variations in mortality. Of the data gathered from field surveys aimed at locating wild boar carcasses, 28 surveys presented detailed information on the application and results of carcass search methods and protocols. Data sources were mainly indexed research and grey literature, with only one item being an interview (from Piedmont, Italy; the remaining interviews only provided general data). These surveys came from eight countries and covered ten different experiences, with one to six surveys each (specific trials by method with more or less aggregated data). Only two of these experiences presented different methods: one in Germany, which presented data on combing, dogs and drones; and one in France (on the border with Belgium), which presented data on surveys using patrols, combing and dogs separately. Therefore, the available information is scarce, incomplete and unharmonized, which may prevent a more detailed description and assessment of methods and strategies. Nevertheless, it is valuable, as we detail below, as relevant recommendations could be distilled from the reviewed literature. We found that the effort applied to finding wild boar carcasses varied considerably. For example, the average number of people in teams participating in surveys ranged from five to ten people in most cases. The area screened per team per day also varied widely, from a few hectares (ha) to almost 1000 ha, with most values around 100–200 hectares per team per day. In terms of person per day, the screened surface ranged from a few hectares to 50 hectares, peaking in frequency at 15–20 hectares. The average distance travelled per day was 5.6 km, with most values falling between 2 and 3 km. The average speed was mostly between 0.25 and 0.75 km/h, with some values above 1 km/h when dogs were used. Dogs were employed both to complement human efforts in searching for wild boar carcasses and as an effective standalone method when trained dogs were utilized. Estimations of the number of retrieved carcasses relative to the estimated wild boar population in the area varied widely, but these are probably not very accurate and are likely to be biased. This is mainly due to the generally unknown size of the current wild boar population. Regarding the description of the data collected from surveys on the search for wild boar carcasses using different methods, we are aware that the number of relevant surveys is limited when it comes to characterising performance and logistical issues depending on the method. Not all of the data that we aimed to collect was collected for all of the surveys (data on effort and efficiency were an exception). We present figures showing the area screened by a team per day and the distance travelled (in km) per event and per day by a team for different Review: methods to find and date wild boar carcasses 6 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). methods, which show that this distance tended to be lower for combing. We also present the travelled distance (km) per event and per day by teams participating in wild boar carcass search activities for different methods. Even when the screened area and travelled distance seemed to be lower for combing, this approach is generally more labour-intensive. We collected information on the main factors reported as determining the applicability and performance of different wild boar carcass search strategies; to provide evidence on their relative importance (i.e. how frequently these factors were reported in our survey). The most frequently reported factors in our sample were: 1) knowledge of local wild boar ecology, density and spatial corridors; 2) economic compensation; 3) the use of trained sniffer dogs; 4) the coordination of administrations and continuous monitoring/feedback; 5) weather and season; 6) local environmental characteristics (e.g., vegetation) affecting carcass detectability; and 7) the use of different complementary methods. It is evident that the relevance of different factors is context specific and depends on the local scenario and applied methods. We compiled recommendations mainly from indexed papers and from questionnaires. In some cases, the effort applied was determined, but the lack of detailed information and the use of different metrics prevented comparisons between methods, designs (e.g. grid-based vs habitat), strategies, areas and epidemiological scenarios, as well as determining real efficacy in terms of the proportion of carcasses found. The latter could only be addressed through experimental trials. However, due to the comparable nature of the landscape and wild boar ecology across its distribution range, the presented strategies could potentially be adapted for Central and Southern Europe to facilitate the search for infected carcasses according to local conditions. Dating of wild boar carcasses: A total of 48 documents were collected, including 43 research papers, three questionnaires, one book and one PhD thesis. Two items of different nature (presentations) were also initially screened. A total of 48 documents were collected, including 43 research papers. Of these, 11 were selected for further evaluation of carcass dating methods, as they either specifically addressed wild boar or described methods originally developed for other species but later adapted for application to wild boar. However, all references were screened in detail and the data were included in the data set, since they could provide relevant, directly transferable information for the evaluation of carcass dating methods in wild boar. For instance, this included references to other species (wildlife, pigs, humans), as well as references incorporating carcass PMI estimations into epidemiological models (e.g. several reports by EFSA). Three of these studies were conducted in areas infected with ASF in Europe, specifically in regions classified as Atlantic, Continental and Alpine (mainly Central Europe). However, comparable studies from other temperate regions were conducted in South Korea (n = 4). Of the eleven documents focusing specifically on wild boar, four were classified as experimental, meaning that wild boar carcasses were used in controlled experiments to evaluate the decay process with rigorously known PMI. In contrast, the remaining seven sources evaluated carcass dating methods based on field observations, where the exact PMI was unknown. From a different point of view, two of the eleven references were original meaning that the authors developed their own methodology to determine PMI in wild boar carcasses. The remaining 9 sources applied or adapted methodology that had already been described using human or other animal models. The methodological approaches most frequently described were based on the following original sources: Megyesi et al. (2005) assessing PMI on human remains, either alone or in combination with other references, in four cases; Goff (2009) (human remains); Anderson and Laehroven (1996) (pig’s carcasses); and Parsons and Keough (2009) (pig’s carcasses). Several studies adopted Probst et al. (2020) (wild boar carcasses), which in turn relied on Megyesi et al. (2005, adapted). Review: methods to find and date wild boar carcasses 7 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). The most frequently used approach was the direct macroscopic description of the decay/decomposition process, which normally included categorisation into different stages over time, either alone or in combination with other approaches. Macroscopic changes were also frequently monitored using camera traps. Metabolomics, entomology and histology were used to a lesser extent in our sample. Usually, one method was applied to date wild boar carcasses (most frequently macroscopic evaluation), but some studies applied up to five methods to address carcass dating. Different phases of decomposition were determined based on macroscopic evidence, variably according to the study. Therefore, the number of categories of decomposition used was also variable. The number of such categories all over the process (not only at early stages) were more frequently classified into four categories well represented by this terminology: fresh, early decomposition, advanced decomposition, and skeletonization/mummification. In addition, three studies scored the decomposition process based on methodology developed by Brooks et al 2018, Megyesi et al. (2005), and a further adaptation to wild boar by Probst et al. (2020). Among the various parameters described during the decomposition process, season and habitat or microhabitat conditions were the most frequently considered factors in the selected studies. Environmental temperature and accumulated degree-days (ADD)—reflecting the total heat exposure and insolation affecting the carcass—were also commonly taken into account, along with the influence of scavengers on the decay process. Other factors, such as body size (or age as a proxy) and insect activity, were considered less frequently. Quantification of decomposition in terms of days was possible primarily in experimental studies or those focusing on the early post-mortem stages. For later stages of decomposition, field observations provided PMI estimates expressed more broadly in days, weeks, or months. Discussion Regarding wild boar carcass search: - Despite the crucial importance of removing wild boar carcasses as soon as the first cases are detected in an area (and during subsequent stages), there is a noticeable lack of protocols and guidelines for locating these carcasses. - This scarcity of protocols and guidance on searching for wild boar carcasses indicates the need to publicise and share what is already known locally based on experience, particularly regarding ASF outbreaks across Europe. - Relevant research has been conducted in Central Europe in relation to wild boar carcass searches and dating. Further testing and adaptation of these studies in different biogeographical and epidemiological scenarios is needed to assess their efficiency in carcass search and carcass dating, and to determine their adaptability to different scenarios in Europe. - In Europe, most of the literature on this subject originates from countries affected by ASF. Most national veterinary administrations responded that no systematic protocol for searching for wild boar carcasses exists. We advocate agreeing on and incorporating detailed guidance on wild boar carcass searches as part of the wild boar population control and monitoring plan requested by the Commission from countries as part of the fight against ASF. - The priority criteria used in the literature we surveyed to select areas for searching for wild boar carcasses are mainly related to the increased risk of finding dead wild boars and the estimated risk of ASF. The optimal approach may involve integrating different strategies to maximise effectiveness. Habitat-based strategies are more efficient in targeted areas where wild boar activity is known, whereas grid-based strategies provide comprehensive coverage and are useful in areas where habitat data is limited. Features usually considered Review: methods to find and date wild boar carcasses 8 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). for a habitat-based strategy include the presence of primary forest types, proximity to water sources, terrain and areas with minimal human disturbance. - A significant obstacle to developing carcass search strategies based on existing knowledge is the limited available data. Furthermore, the effectiveness of wild boar searches is rarely quantified, and when it is, the methods and metrics employed are often not comparable. The ratio of found to hidden carcasses is mostly unknown. Another relevant issue with the current data is the scarcity of method comparisons, particularly fair comparisons under similar conditions. - Guidance is needed on the efforts and resources required to be deployed over time. The parameters provided here offer some direction in determining the necessary human effort. - The main factors reported in the literature that determine the applicability and performance of different wild boar carcass search protocols are of a different nature. The relevance of these factors depends on the local scenario and the methods applied; even a given factor may diminish or increase efficacy under different circumstances. - Surveillance and search techniques, such as active ground searches by humans or aerial surveillance, are far from 100% effective. While this review identified four main methods for the active detection of wild boar carcasses, an integrated approach could improve the efficiency and effectiveness of surveillance efforts, particularly in hard-to-reach areas: • Ground survey teams may work alongside other surveillance tools, such as drones equipped with thermal imaging cameras and carcass-detection dogs. • Specifically, patrolling known or potential hotspots for wild boar activity or death beds by car (risk-based surveillance) complements more systematic searches conducted by teams of searchers, drones and dogs. This is particularly useful for the initial, preliminary estimation of the infected area, after which more systematic search activities can be developed. • Searching for carcasses with specially trained dogs is an effective method, even in closed vegetation environments and for small carcasses. Well-trained dogs are arguably the most portable and versatile carcass detection tools in use today. - Further integration and generalisation of the use of drone technology in wildlife surveillance is a promising yet still unexploited area. Drones equipped with thermal imaging cameras have been used to monitor wild boar populations, improving surveillance and containment efforts in hard-to-reach areas and offering the potential for the rapid, efficient and safe detection of wild boar carcasses. The following experimental areas require further development to generate reliable, practical data for decision-making across various situations and contexts: - Comparative search studies should assess the effectiveness of different detection methods. Such trials need to be designed to allow results to be compared across different areas using consistent or standardized metrics. - The probability of detecting a wild boar carcass within a given area must be quantified. This involves placing carcasses with a known location in the field and conducting repeated searches to estimate detection rates. - The performance of trained detection dogs should be evaluated in diverse habitats and under varying weather conditions, to assess how environmental factors and carcass decomposition stages influence detection success. - Further research is needed on the integration of technology, particularly drone systems, to compare the efficiency of aerial and ground-based searches and to develop automated wild boar detection capabilities. As for wild boar carcass dating: Review: methods to find and date wild boar carcasses 9 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Determining PMI in wild boar is highly context-specific, depending on factors such as habitat and climatic conditions, and is thus exceptionally challenging. Apart from some experimental studies (i.e. studies with known PMI), there are no validated, adapted protocols or detailed guidance on dating wild boar carcasses during an active outbreak that can be used across all European regions and environments. Although known experiences from Central Europe can be adapted for use in other areas, regional studies with a similar methodology are still required. - The recent development of methods such as metabolomics-based approaches is promising, but further development, as well as the appropriate facilities and expertise, is required for rapid assessment. - Estimated post-mortem interval (PMI) using “classical” forensic techniques still presents a wide range of uncertainty based on experimental studies, with this range increasing as time elapses since death. - Decomposition stages, which are mostly based on macroscopic evidence, cannot be universally associated with specific PMI, as this depends on the specific context and conditions. Due to the complexity of the factors involved, models or automatic algorithms to estimate PMI for wild boars may probably only be precise locally. - Season, habitat and microhabitat conditions were the most frequently considered factors impacting PMI, body size (or age as a proxy) and insect activity and scavengers. - The main considerations that need to be accounted for when determining the PMI in wild boar across Europe are: (i) extreme environmental variability, meaning that extrapolating data from studies in different areas/bioregions is probably unreliable; (ii) aspects related to specific decomposition processes in wild boar; (ii) extrapolating data from human studies or even from domestic pigs is also unreliable; (iii) unpredictable scavenger and insect activity, which is characteristic of a given area or bioregion; and (iv) the fact that accessing and analysing wild boar carcasses in remote locations often requires fieldwork. entomological analysis or lab support. The development and validation of new methods based on an understanding of the changes that occur in metabolomics post-mortem are promising, as is the combination of different approaches. To summarize, determining the PMI in wild boar requires a variety of experiments to be conducted in various environmental settings to build a comprehensive understanding of PMI across Europe, including decomposition studies, and controlled environmental studies. This will also provide the necessary baseline data for forensic pathologists and ecologists dealing with wild boar carcasses. Review: methods to find and date wild boar carcasses 16 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). 6.A) To provide a review of different methods to find wild boar carcasses in different countries, and the methods to date those carcasses, based on literature and field experience. This is addressed in the present report. 6.B) To propose protocols of use for each carcass detection system and carcass dating in different environments, how to adjust the effort depending on factors such as prevalence/seasons/etc. This is addressed in a further report. Scope of the report The report aims to review different methods to find wild boar carcasses in different countries, and the methods to date those carcasses considering different environments and considering the main factors determining their efficacy and practical application in the field (ToR 6.A). Review: methods to find and date wild boar carcasses 17 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). 3. Methods The literature review considered a comprehensive range of sources, including published peerreviewed articles, grey literature (such as technical reports and relevant websites), and direct insights gathered through semi-structured interviews with national-level experts involved in the management and prevention of ASF outbreaks in Europe. The inclusion of additional sources beyond published scientific literature was necessary due to the limited number and scope of peer-reviewed studies, which do not fully capture the evolving expertise and practical knowledge currently being developed and applied at the EU level. Grey literature and expert interviews provide essential, up-to-date insights from field experience and national management practices that are not yet reflected in the published scientific record. 3.1. Wild boar carcass search Literature on wild boar carcass search Figure 1 illustrates the general procedure, organization of work and steps performed to review literature on wild boar carcass search and their characterization by the consortium. The review of grey literature was based on using the same terms in general web browsers, as well as direct interviews to national administrations. Review: methods to find and date wild boar carcasses 18 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 1. Procedure and steps performed to review the literature on wild boar carcass search. Our approach aimed at searching academic, peer-reviewed articles/documents describing wild boar carcass dating methods and protocols, their characterization and determining factors in: ● Biomedical databases (Medline) ● Science databases (Web of Science, Scopus) ● Two search strings we consecutively used. The first was: (("wild boar") OR ("Feral pig") OR ("feral hog") OR ("feral swine")) AND (("carcass detection") OR ("carcass search") OR ("carcass removal") OR ("detecting carcasses") OR ("searching carcasses") OR ("finding carcasses") OR (“removing carcasses”) OR (“locate wild boar carcasses”) OR (“carcass location”) OR ("wild boar carcasses") OR (deathbed) OR ("carcass detection dogs") OR ("collection of carcasses") OR (“Managing carcasses”) OR (“found-death”) OR (“dead wild boars”)) Additionally, in order to focus more specially and retrieve literature on drones as an approach to find wild boar carcasses, we used a second search sting as follows: ("wildlife") AND (("carcass detection") OR ("carcass search") OR ("carcass removal") OR ("detecting carcasses") OR ("searching carcasses") OR ("finding carcasses") OR (“removing carcasses”) OR (“locate carcasses”) OR (“carcass location”) OR ("carcasses") OR (deathbed) OR ("collection of carcasses") OR (“Managing carcasses”) OR (“found-death”) OR (“dead wildlife”)) AND ((drone) OR (UAV) OR (Unmanned)) Duplicates were removed. In addition to references retrieved directly from scientific browsers, we examined the literature cited to identify missing references and grey/technical literature (institutional literature/reports) and webs (using same search term in general browsers). Grey literature was search using the following national languages: Spanish, French, German, Italian, Polish, Czech, Swedish, Latvian, Estonian and Lithuanian. No time restrictions were applied to the inclusion of papers. All these references were managed in Zotero web library, and finally, collated in our data form. 3.1.1. Criteria for inclusion in the review The criteria for inclusion in the review were: ● It deals with wild boar or relatives (e.g., feral pig) carcass search ● AND/OR provides relevant elements, not necessarily a protocol, that applies to wildlife carcass search in the field and could be applicable to wild boar, which fits our data collection models (see below). Subsequent screening for exclusion prevented the use double entries (original articles can be part of reviews and/or grey literature). 3.1.2. Direct interviews To complement the information obtained from the literature, address regional data gaps, and incorporate hands-on experience, additional data were collected by distributing the same standardized data collection form to national and local authorities or individual experts involved in active carcass search efforts. This was done in most cases through direct interviews to clarify doubtful points and enhance discussion. These efforts included both real-world scenarios and simulation exercises and were conducted by veterinary authorities, wildlife agencies, CVOs, and other relevant institutions which were, owing to their assigned duty, responsible for the coordination of wild boar carcasses search or directly involved in it. 3.1.3. The questionnaire and data form A data form (excel form) was used to collect key information for characterizing wild boar carcass search activities. It was also used as a questionnaire/interview script for administrations. It is divided into two main parts (sheets): Review: methods to find and date wild boar carcasses 19 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). ● Description of the method/protocol to find wild boar carcass (Table 1). If available, data on its application or surveys, which is useful to evaluate efficiency and determining factors (Table 2). The data form was also used to guide direct interviews. Data was entered in the final database (Figure 1). Table 1. First part (description of the method/protocol to find wild boar carcass) of the data form used to extract key information to characterize wild boar carcass search. ID Document General Name and brief description of the WB carcass search program/activities Country Region/province Brief description of typical landscape of the region where protocol is used (free text) Epidemiological scenario of application: 1) Infected area; 2) at the border with the infected area (< 10 km); 3) ASF free and intensive hunting areas Epidemiological scenario of application (II) 1) focal outbreak; 2) large front of disease Resources (protocol, report, paper) in the web (indicate web address) Main OBJECTIVES of program/report/protocol application (literally, summarize if long) Organization Administration body in charge: protocol development Administration body in charge: implementation Administration body in charge: data elaboration THE PROTOCOL Method/protocol: 1) Prospective patrols in sites favourable for dead WB presence; 2) Systematic combing of an area; 3) Dog detection, 4) Drones Brief description of the protocol (free text) ID Method (example provided) Criteria to select the searching zone/transect previous notifications of carcasses, proximity to risk (e.g., country borders, habitat connectivity), epidemiological models, random or regular within a given area, accessibility, etc When planning a search, do you pay special attention to environmental features present (e.g. mud, water holes, feeding grounds, fences, small rivers). Y/N In case of application of prospective patrols, detail the environmental features selected (e.g., mud, water holes, feeding grounds, fences, small rivers WB carcasses dated? Y/N Concomitant use of drones? (Y/N) Effort: recommended team size (average or range) Effort: nº search events/day*team Effort: recommended area beaten per team*search event (ha) Effort: recommended area beaten per team*day (ha) Effort: length (km, average) search event Effort: length (km, average) day Effort: average speed (km/h) Review: methods to find and date wild boar carcasses 20 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Effort: time (hours a day per team) Distance between people (m) Which is the metric used to estimate EFFICACY? (in WB carcass detection) Who supervises/leads each team? (e.g., a local forestry officer) Participant: veterinarian (Y/N/Optional) Participant: hunters (Y/N/Optional) Participant: forestry/rangers (Y/N/Optional) Participant: military (Y/N/Optional) Participant: farmers(Y/N/Optional) Participant: Fireguards (Y/N/Optional) Participant: Police (Y/N/Optional) Other government departments (indicate which) Other stakeholders (indicate which) Participant: dog handlers (Y/N/Optional) Nº trained dogs per team Nº untrained dogs per team Dog training: how long for, and specific target Dog breeds used Institutional or private body training the dogs Use of walkie-talkie by the team during search Financial compensation per field session? How much? Frequency a given area is screened Frequency team go to field (days) Specific form to be filled out and compiled after search session? (Y/N) Provide it WB carcasses position signalling method (GPS, GPS in smartphone and app like WhatsApp, visible tape, ...) Specific app developed to record, or trace or share field data. Indicate which Team trained on ASF biosecurity? Team trained on search protocol? First aid equipment available during search? Disinfection protocol included? (Biosecurity measures adopted before and after search) Disinfection equipment available during search? SPECIFIC awareness-raising and education campaign on Passive surveillance aimed at target stakeholders? Namely the importance of removing WB carcasses Drone specific questions Who operates drones? Thermal imaging used in drones Period of the day: 1) Any, 2) Diurnal, 3) nocturnal Type of drone: 1) multi-rotor, 2) fixed wing aircraft Drone model (and also camera model if external) Area (ha) beaten per flight Area (ha) beaten per day Height (altitude) of flight (indicate m, or if variable) Review: methods to find and date wild boar carcasses 21 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Results are immediate or do collected images require further processing? How long? Automatized processing of images? Y/N, describe Search strategy (free text): indicating if systematic survey (pre-defined) or manually guided towards more risky or suspicious sites Table 2. Second part (application or surveys to search wild boar carcasses in the field in order to evaluate efficiency and determining factors) of the data form used to extract key information to characterize wild boar carcass search. This part of the data form is linked to part 1 through the ID. ID Document ID method Site Habitat description (in view of visibility and accessibility characteristics) Latitude Longitude Epidemiological scenario of application (I): 1) Infected area, 2) at the border with the infected area (> 7 km); 3) free and intensive hunting areas, 4) Drones Epidemiological scenario of application (II): 1) focal outbreak vs 2) large front of disease Main habitat type (EUNIS): Coastal habitats, wetlands, grasslands, heathlands and scrub, forests, sparsely vegetated habitats, farmlands Habitat description: accessibility (rank accessibility of the searched area from 1 (lowest, absence of roads, deep slopes and cliffs, large areas of wetlands and associated vegetation ) to 5 (highest, abundant roads, flat terrain) Habitat description: visibility (rank visibility at 5m from 1 (lowest, totally covered by vegetation) to 5 (highest, almost no vegetation present) Experimental study (Y(N) Experimental objectives Experimental group (indicate group) Single search or aggregated data (single/aggregated). You can provide single search data in different rows, or aggregated in a single row if aggregated data is reported, indicate duration (nº days) and nº of search events considered Date (exact date or period, and duration of activities: total nº of days) WB known or estimated density? Indicate (total or nº ind./km2) Obligate scavengers (vultures) present in the area (Y/N) Surveillance effort as hours*person (per singe event as nº people x nº hours, or total, measured by calculating the total number of field sessions, their duration, and the total Review: methods to find and date wild boar carcasses 22 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). human involvement in hours -duration of each field session multiplied by the number of people involved-) Effort: Actual team size (average or range) Effort: nº search events/day*team Effort: actual area beaten per team*search event (ha) Effort: actual area beaten per team*day (ha) Effort: actual length (km, average) of search event Effort: actual length (km, average) day Effort: actual average speed (km/h) Effort: actual time (hours a day) EFFICACY (specify metrics and unit) Participant: veterinarian (Nº per team) Participant: hunters (Nº per team) Participant: forestry/rangers (Nº per team) Participant: military (Nº per team) Participant: farmers (Nº per team) Participant: Fireguards (Nº per team) Participant: Police (Nº per team) Other government departments (indicate which and nº) Other stakeholders (indicate which and nº) Participant: dog handlers (Nº per team) Nº trained dogs per team Nº untrained dogs per team Notes: anything regarding the search strategy and effort (free text) Time since last search Efficacy: number of carcasses collected Efficacy: measure (description of metrics). E.g., by dividing the number of carcasses detected by the WB population Estimated cost of search operations Euros/ha*day 3.2. Wild boar carcass dating 3.2.1. Literature on wild boar carcass dating Figure 2 illustrates the general procedure, organization of work and steps performed to review literature on wild boar carcass dating by the consortium. Similarly to wild boar carcass search, the review of grey literature was based on using the same terms in general web browsers, as well as direct interviews to national administrations. Review: methods to find and date wild boar carcasses 23 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 2. Procedure and steps performed to review the literature to review literature on wild boar carcass dating. Our approach aimed at searching academic, peer-reviewed articles/documents describing wild boar carcass search methods and protocols, their characterization and determining factors in: ● Biomedical databases (Medline) ● Science databases (ISI Web of Science, Scopus) We used the following sting: (“postmortem* interval” AND “wildlife”) OR (“wild boar carcass” AND “dating”) OR (“postmortem interval” AND “wildlife”) OR (“postmortem interval” AND “wild boar") OR (“wild boar carcass” AND “decay”) OR (“wildlife carcass” AND “decay”) OR (“wildlife carcass” AND “dating”) (*) also used as “post-mortem” and “post mortem” Duplicates were removed. In addition to references retrieved directly from scientific browsers, we examined the literature cited to identify missing references and grey/technical literature (institutional literature/reports) and webs (using same search term in general browsers), and all these references were managed in Zotero web library, and finally, target information was collated in our data form. As done for the previous search, we also involved direct interviews with authorities (usually veterinary authorities) who had hands-on experience on the topic, (i.e., performed wild boar carcass dating during WSF outbreaks), to gather basic information on availability of carcass dating protocols as well as to identify additional grey literature and expert’s insights. Grey literature was search using the following national languages: Spanish, French, German, Italian, Review: methods to find and date wild boar carcasses 24 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Polish, Czech, Swedish, Latvian, Estonian and Lithuanian. No time restrictions were applied to the inclusion of papers. To complement literature review, veterinary services, and the European networks of wildlife veterinarians (such as the EWDA Wildlife Health Network) were contacted to be eventually interviewed. The criteria for inclusion in the review studies were: ● It deals with wild boar or related species (e.g., feral pig) carcass search ● AND/OR provides relevant elements, not necessarily a protocol, for improving wildlife carcass in the field (therefore applicable to wild boar), which fits our data collection models (see below). This includes factors that may determine wildlife (medium to big size) carcass search in the field. Subsequent screening for exclusion prevented the use double entries (original articles can be part of reviews and/or grey literature). Review: methods to find and date wild boar carcasses 25 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). 3.3. The questionnaire and data form Information from the questionnaire and the literature review was compiled through ad-hoc data collection forms. Table 3 shows this questionnaire. Table 3. Data extraction form used for the analysis of literature sources and interviews Geographical region where the study was carried out (i.e., country + bioregion) Which type of carcass dating protocol is evaluated in the paper? Original Reproduced Adapted If it was reproduced or adapted, from which protocol was it adapted? Please provide APA reference is available If it was adapted, what was changed from the original protocol? Which tools were implemented in the protocol? Metabolomics Insect communities’ evaluation Macroscopic analysis Camera trap monitoring for macroscopic analysis Histology Protein degradation analysis Other: Which other parameters were considered for assessing the dating protocol? Environment/habitat/vegetation Different geographical areas Soil Body part interested Sun/shade Age class Sex Body mass Animal species Duration of the study Season for carcass ‘initial deployment Consumption by scavengers Other: What is the dating resolution? Can this protocol be applied to different conditions? Yes to different seasons Yes to different species Yes to different bioclimatic areas Review: methods to find and date wild boar carcasses 32 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 8. Frequency (n=60 literature items) of predominant criteria to select the area to perform wild boar carcass. The average team size (considering all different types of methods) is shown in Figure 9 (left), indicating that teams below 10 people (mainly between 3 and 8) predominated. In several cases (not shown) the answer was “maximum possible” but no specific indications were provided. In most cases, one single carcass search event is organized per day, and the maximal number is 3 (Figure 9 right). Figure 9. Left: Average team size considering all different types of methods (n=18). Right: number of wild boar carcass search events practiced by team*day. The area covered during each wild boar carcass search event (Figure 10, left), which closely matched the area surveyed per day (Figure 10, right), as typically one search event was conducted daily, showed considerable variability. The surveyed areas ranged from 6 to 750 hectares, with a typical (modal) value of approximately 100 hectares. Review: methods to find and date wild boar carcasses 33 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 10. Area surveyed per wild boar carcass search event (left) and per day (right), which were largely similar as typically one search event was conducted each day. Only a few values were available for the distance travelled per event (n = 4), ranging from 1 to 6 km (2 to 6 km when considering distance travelled per event, n = 4). Average speed values were reported in four cases and ranged from 0.25 to 5.30 km/h, with the latter figure corresponding to dogs. The average number of hours spent searching for wild boar carcasses in the field per day was 4 (the typical value), ranging from 3 to 5 hours per day. As indicated in Figure 11, the way in which the performance of wild boar searches was quantified was very variable. This result highlights the difficulty of comparing studies, experiences and methods. While an experimental study could compare the number of carcasses found relative to those hidden, in real scenarios the number of carcasses was usually unknown. In some cases, however, a number could be predicted based on modelling. Performance can also be estimated relative to the wild boar population, but population estimates are usually unreliable and do not account for the specific local impact of mortality. Figure 11. Frequency of the way to quantify the performance of wild boar search over analysed cases. Figure 12 shows the frequency of the responsible persons. Veterinarians were in charge of organisations searching for wild boar carcasses in the field, followed by officers from the hunting, forestry or park departments. To a lesser extent, hunters and professional dog trainers were also involved. Figure 13 shows the relative contribution of different stakeholders in terms of their presence in wild boar carcass search field teams. Hunters and dog handlers (who are often also hunters) were the most represented groups, accounting for around 75% of search events. They were followed by vets and forestry rangers (in around 50% of cases) and, to a lesser extent, by the army and the police. Other groups were present in a much lower number of cases (e.g. civil protection, farmers, hired staff, fireguards or firefighters). Review: methods to find and date wild boar carcasses 34 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 12. Frequency of responsible persons for wild boar carcass searching events. Review: methods to find and date wild boar carcasses 35 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Review: methods to find and date wild boar carcasses 36 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 13. Relative (%) presence of different stakeholders in wild boar carcass search field teams. N: absent, Y: present, O: optional (n=30). When present (in more than 50% of cases, n=30), the total number of dogs per team mostly ranged between one and two (Figure 14 top -1), with a maximum of 9, and they were mostly trained dogs (bottom -2). The total number of trained dogs per team (bottom left - 2A) presented a similar pattern, whereas untrained dogs were less frequently present and at lower numbers (one dog per team, bottom right - 2B). Figure 14. Frequencies of the total number of dogs per team (top), total number of trained dogs per team (centre), and total number of untrained dogs per team (bottom) (n=30). Dogs were primarily trained by private organizations, and to a lesser extent, associations (scent dog breeders) and the administration (Figure 15). Review: methods to find and date wild boar carcasses 37 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 15. Organizations responsible for training the dogs (%). Figure 16 (left) shows the frequency a given area is screened in our sample. While only for some methods the selected areas are surveyed once, normally, wild boar carcass search areas are screened every 2 weeks, which can extend to every 6 months in some cases. The frequency (how often, assuming certain regularity) teams go to wild boar carcass search activities was variable, in the majority of cases daily or weekly. Figure 16. Organizations responsible for training the dogs (%). Dogs were primarily trained by private organizations, and to a lesser extent, by associations (such as scent dog breeders) and the administration. Review: methods to find and date wild boar carcasses 38 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). The way the information on wild boar carcass presence and geolocation is collected and communicated is normally through GPS (Figure 17), which can be incorporated to mobile texting apps (n=20) or national/regional wild boar carcass collection specific ones. Figure 17. The way information on wild boar carcass presence and geolocation (frequency in our sample) is collected and communicated (n=20). In most cases, the field teams received training on biosecurity and disinfection, and were equipped with disinfection stuff (Figure 18, n=25). However, approx. 50% of protocols did not provide the field teams with the first aid equipment (we do not distinguish ASF confirmed and free areas). Review: methods to find and date wild boar carcasses 39 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 18. Frequency of cases in which the field teams received training on biosecurity (top left) and disinfection (bottom left, n=25), and were equipped with disinfection stuff (bottom right). Provision of the field teams with first aid equipment is indicated in the top right figure. Specifically regarding the use of drones to detect wild boar carcasses, most of the operators were private in our reduced sample (see Figure 19 on the left). The investigation revealed no significant preference for the time of day to operate drones, with diurnal flights being favoured over nocturnal ones (Figure 19, right). All of the operators used thermal imaging to detect wild boar carcasses. Based on a reduced sample size (n = 6), the area screened per day presented a wide variation in size (from 10 ha in experimental studies to 500 ha in real cases), averaging 218 ha overall (70.6 SE). Figure 19. Regarding the use of drones, most of the operators were private in our reduced sample (left). The preferred period of the day to fly drones was any (1), followed by diurnal flights (2), and to a lesser extent, nocturnal (3) and nocturnal combined with diurnal (2/3) (right). 4.1.3. Specific characteristics of different method/protocols to find wild boar carcasses When we visualized the application of different methods in different countries (attending to those with higher representation in our sample, Figure 20), we evidenced marked differences. When selecting the countries where most of the information was collected, we evidenced that the use of dogs and drones predominated in Germany, combing by foot in Poland, and different approaches were similarly present in our sample in Italy (predominating combing). Review: methods to find and date wild boar carcasses 40 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 20. Visualization of the application of different methods in different countries (attending to those with higher representation in our sample). Regarding the use of methods to search wild boar carcasses in infected versus border areas (Figure 21, left), we found that different approaches were used in infected areas. Notably, a combination of methods was used more frequently, whereas patrolling was used less frequently. In border areas, combing was the most frequently selected approach, followed by patrolling. Dogs and drones were used less frequently. In terms of the comparison between focal and large-front outbreaks (Figure 21, right), patrolling and combing were the most frequently selected options for large-front outbreaks. For focal outbreaks, patrolling was never selected alone (it may be combined with other methods), and carcass searches were based on other methods. These comparisons are also visualised as sector diagrams (Figure 22). Figure 21. Application of different methods regarding the epidemiological scenario. The left figure regards the use of methods in the infected versus the border area (<10 km), whereas the right figure refers to the comparison of focal versus large front outbreaks. Review: methods to find and date wild boar carcasses 41 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 22. The application of various methods across different countries is depicted through sector diagrams, which align with the epidemiological scenarios. The figure in the top left illustrates the methods used in areas with infections, while the top right figure pertains to border regions. In the bottom section, the diagrams display the application of methods in different countries, tailored to specific epidemiological contexts. The bottom left figure focuses on the methods employed during focal outbreaks, and the bottom right figure addresses the strategies used along extensive fronts of ASF outbreaks. Out of a total of 19 responses, 15 were from financially compensated searchers. However, our sample size was too small to enable us to compare the efforts and performance of the search according to this variable. As an example, compensation ranged from 0 to 120 euros per person per day for ground teams, 500 euros per day for drone teams (which is probably within the lower range for drones) and 450 euros per day per dog plus 250 euros per day per handler-assistant for dog teams. Figure 23 shows the frequency (n) of area (ha) screened in a day according to the method used to find wild boar carcasses. The central values for combing and drones were approximately 100 and 150–200 hectares, respectively, with significant variation. Details of the specific surveys for each method are provided in a further section. Review: methods to find and date wild boar carcasses 48 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). 4.1.5. Description of data collected on surveys for searching wild boar carcasses by different methods In this section, we describe the data collected from a limited number of surveys on searching for wild boar carcasses, which may be relevant for characterising performance and logistical issues as a function of the applied method. Not all data were collected for all surveys and, specifically, for all methods of searching for wild boar carcasses. Figure 30 shows box plots of the area screened by a team per day, indicating that the total area screened may be smaller for combing than for dogs and drones. Figure 30. Box plots of the screened surface (ha) by a team and day, as a function of the method. The Figure 31 illustrates the travelled distance (km) per event and per day, respectively, by a team for different methods, evidencing that this distance tended to be lower for combing. Figure 31. The travelled distance (km) per event (left) and per day (right) by teams of people participating in wild boar carcass search activities for different methods. Figure 32 illustrates that even when the screened area and travelled distance seemed to be lower for combing, this approach also tends to require more dedication of people in terms of hours a day. Review: methods to find and date wild boar carcasses 49 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 32. illustration of the dedication of people participating in wild boar search activities in terms of hours a day. 4.1.6. Identification of the main factors determining practical application of wild boar search methods in the field We collected information on the main factors determining the applicability and performance of different wild boar carcass search, first, to identify them and secondly to determine their relative importance (in terms of the frequency these factors were reported over our survey). These factors are listed (1-18), and their frequency summarized (n=30) for all methods in Figure 33. Review: methods to find and date wild boar carcasses 50 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 33. List of factors determining the applicability and performance of different wild boar carcass search methods and strategies reported over the collected surveys (N=30). They are ranked as a function of their frequency for all methods. The factors that were more frequently reported are as follows: ● Knowledge on WB ecology, density, and spatial corridors ● Economic compensation ● Use of trained detection dogs ● Previous coordination of administrations and continuous monitoring/feedback ● Weather and season ● Visibility of carcasses: which is mainly determined by vegetation ● Use of complementary different methods These factors are of a different nature. They may relate to wild boar ecology, the environment and climate, or to how the search is organised at different stages, including economic compensation for searchers and the means used, such as trained dogs and combined methods. Clearly, the relevance of these factors depends on the local scenario and the methods employed, even though their efficacy may diminish or increase under different circumstances. The next report will discuss the practical consideration of each factor in different scenarios and methods, providing guidance and practical recommendations for efficient wild boar carcass search programmes. 4.2. Wild boar carcass dating 4.2.1. Available data A total of 48 documents were collected, including 43 research papers, three questionnaires, one book, one PhD thesis (which was not translated into the original publication). Two items of different nature (presentations) were also initially screened. Although eleven documents were selected for in-depth evaluation because they specifically addressed wild boar or described carcass dating methods later applied to wild boar, all identified references were screened in detail and assessed for potentially relevant information. Where applicable, data from these additional sources—covering other species (e.g., pigs, humans), wildlife in general, or the use of post-mortem interval (PMI) estimates in epidemiological models (e.g., EFSA reports)—were extracted using the data extraction form. This allowed for a more comprehensive understanding of the methods, even if these studies did not meet the initial inclusion criteria focused on wild boar. While data from these broader sources are not presented in this review, as the analysis was specifically targeted at wild boar, they remain available and could support future, species-specific or comparative analyses. This approach reflects a pragmatic adjustment to the selection criteria, recognizing the limited availability of wild boar-specific studies and the relevance of transferable knowledge from other contexts. Review: methods to find and date wild boar carcasses 51 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). The 11 selected references (see Annex 2) included 10 research papers and one questionnaire (provided by Dr Carlo Citterio regarding ongoing research). Three of these were developed in ASF-infected areas and the geographical distribution was mainly in Europe (see Figure 34), particularly in regions classified as Atlantic, Continental and Alpine (mainly Central Europe). However, similar, comparable studies originated from other temperate areas and were conducted in South Korea (n = 4). In two cases, dating referred to carcasses found in the Mediterranean area (Sardinia, Italy). Figure 34. Geographical distribution of selected literature items (n=11). Considering the references focusing on wild boar carcass dating specifically, four out of the 11 references were classified as experimental (Figure 35), which means that wild boar carcasses were experimentally deployed to evaluate the decay process, and PMI was known. On the other hand, in 7 cases the observations originated from field observations, and the exact PMI was unknown. Review: methods to find and date wild boar carcasses 52 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 35. Frequency of selected references classified as experimental (wild boar carcasses were experimentally deployed and PMI was known) or field observations (the exact PMI was unknown). Of the eleven references, two were original in that they developed their own methodology to determine PMI in wild boar carcasses (Figure 36). The remaining nine applied or adapted methodology that had already been described, using human or animal models. The described methodological approaches were most frequently based on the following original sources: Megyesi et al. (2005) in three cases, and combinations of different references in six cases: Brooks er al. (2018), Goff (2009) Anderson and Laerhoven (1996); Parsons (2009), Keough et al. (2009), Pittner et al., (2020) and Probst et al. (2020). The latter, in turn, relied on the adapted methodology of Megyesi et al. (2005). The adaptation involved the methodology and classification stages, but not the PMI values. Review: methods to find and date wild boar carcasses 53 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 36. Frequency (n) of sources for wild boar carcass dating protocols over the selected references (n=11), as well as indication of the two ones that were original (n=11). Figure 37 shows the frequency with which the different methods of wild boar carcass dating were applied by the selected references (n = 11). Direct morphological analysis of the decay/decomposition process, normally involving categorisation into different stages over time (see below), was the most frequently used method, either on its own or in combination with others (see Annex). This was often achieved using camera traps. Metabolomics, entomology and histology were used to a lesser extent in our sample. Metabolomics is defined as 'the discipline that provides comprehensive and systematic information on temporal changes in metabolite level profiles in biofluids and tissues, arising from the effects of the host genome, extended genomes, and other environmental or promoted factors' (Castillo-Peinado & Castro, 2016). Review: methods to find and date wild boar carcasses 54 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 37. The frequency (number of studies) of different methods applied to wild boar carcass dating by the selected references (n=11). Several methods could be applied in the same studies. Normally, one method was applied to date wild boar carcasses (most frequently macroscopic evaluation; six out of eleven cases). However, some applied three (two cases), four (one case) or five methods (one case) simultaneously to address carcass dating (Figure 38, left). For example, the morphological approach was sometimes coupled with histology. Furthermore, thermal imaging was implemented to assess the body temperature of the carcass. Based on macroscopic evidence, the different phases of decomposition were determined variably according to the study. Therefore, the number of decomposition categories used was also variable. Figure 38 (right) shows the frequencies of the number of categories throughout the process (not only at the early stages). The decomposition status was most frequently classified into four categories, which are well represented by the following terminology: fresh, bloated, active decay, advanced decay, dry remains and skeletal remains. In some cases, post-bloating occurred after bloating but before advanced decay, while in others, mummification occurred after dry remains. Some classifications also use a simpler distinction between early and advanced decomposition. Additionally, three studies evaluated the decomposition process using a methodology developed by Brooks et al. (2018), Megyesi et al. (2005) and Probst et al. (2020), who adapted it for wild boar. Review: methods to find and date wild boar carcasses 55 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Figure 38. Left: Frequency of the number of methods applied per study (n = 11). Right: Frequency of the number of categories used for the classification of the decomposition status after macroscopic evaluation all over the process (not only at early stages) (n = 8). Of the various parameters described during the decomposition process, season and habitat/microhabitat conditions were the most frequently considered factors in the selected studies (Figure 39). Environmental temperature and the ADD score, which is related to the insolation and accumulated temperature hours to which the carcass has been exposed, were also frequently considered, as was the impact of scavengers on the carcass decay process. To a lesser extent, body size (or age as a proxy) was considered over the decomposition process. When analysing their relevance (not always these factors were considered relevant), the figure 39 (bottom) shows in frequency they were considered relevant in our sample (number of references out of 11). Figure 39. Left: the frequency (n) of different parameters that were described during the decomposition/decay process in the wild boar carcass of the selected studies (n=11). Right: the factors that were considered as relevant over our sample in terms of frequency. In general, such parameters affect the precision of PMI estimation, as winter, shade and humidity can slow the decomposition process and hinder correct estimation. Also, differences in skin structure between wild boar and pig can affect the evaluation. A series of factors have been identified as influencing PMI estimation. The most frequently mentioned factors were Review: methods to find and date wild boar carcasses 56 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). temperature (high temperatures speed up decomposition), scavenger activity and environmental exposure (sun, shade, wind and moisture), which were mentioned six times. These were followed by seasonality and insect activity, which were mentioned five times (Figure 39 right). The other factors mentioned were humidity, body mass, species and carcass handling. For experimental studies, frozen carcasses or improper handling may influence the decay. Overall, geographical variability was also mentioned. Figure 40. Resolution of the estimated PMI (n=10). Figure 40 shows the results of the PMI estimation (n = 10). Quantification in terms of days was possible in experimental studies or those focusing on the early stages. However, in field observations where PMI provided estimations in terms of weeks or months, the accuracy and precision decreased with the progression of the decomposition. Generally, the accuracy and precision of the estimations decrease with the progression of the decomposition, meaning both the reliability of the estimation and the uncertainty of the time span (from days to months). Regarding adaptability and applicability under varying conditions, the need for adaptation was frequently noted. These corresponded to factors influencing carcass decomposition, including species, seasonality, scavenger activity, temperature and environmental conditions. Overall, the importance of tailoring approaches to different bioclimatic zones and ASF-affected regions was emphasised. Additionally, the importance of establishing experimental reference settings under controlled conditions was highlighted, as was the need for proper training of operators and experts and the provision of specialised equipment and expertise. Review: methods to find and date wild boar carcasses 57 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). 5. Discussion 5.1. Wild boar carcass search Eradicating ASF from wild boar populations is a complex process requiring a multifaceted approach. Detecting and removing wild boar carcasses in ASF-affected areas is key to improving the management of risk. The aim of this report is to review the methods used to locate wild boar carcasses and date them in different countries. This section focuses on descriptive aspects, paying attention to the main factors that may affect the efficacy and practical application of these methods in the field. A further report will provide guidance on using each carcass detection system and carcass dating method in different environments, offering a practical perspective for adapting them to specific scenarios. Since ASF was last introduced in wild boar in Europe, two key developments have emerged: the continued spread of the disease to new areas, including new regions in Western Europe, and a better theoretical and empirical understanding of the most effective interventions for controlling the spread of ASF in different areas. However, this has not yet been sufficient to stop the spread of ASF beyond some successful and highly illustrative cases of focal outbreaks. Today, the disease remains challenging to eradicate from European wild boar populations, which are reaching unprecedented numbers and continuing to expand. This is due to ASF being transmissible by different routes, as well as the lack of a vaccine, among other factors. 5.1.1 The relevance of systematic and rapid response In this context, the efficient detection and removal of wild boar carcasses in ASF-affected areas has been demonstrated to be key to improving risk management. This review shows that, 20 years after the last introduction of ASF in wild boar in Europe, the best methods and guidance for finding wild boar carcasses remain unharmonised and the information is difficult to access. There is also a lack of methodologies for locally adapted interventions according to scenario. For example, EFSA noted the need to develop protocols aimed at improving the search for wild boar carcasses as early as 2021. In the current context, the aim of this review is to identify accessible information. The data collected is valuable given its scarcity and the fact that it is diversified over many different sources and formats. It is generally incomplete and is normally described superficially, making it hard to harmonise and compare across geography, epidemiological situations and socioeconomic contexts. There is also a need to develop field trials to test the efficiency and precision of carcass search and dating, and to assess their adaptability to different scenarios. Actually, relevant research steps (mainly in central Europe) have recently been done in relation to the two issues evaluated in this review. These studies imperatively require further testing and adaptation over different biogeographical and epidemiological realities in Europe. Regarding the initial steps to control the spread of the disease after the first cases of ASF were confirmed in wild boar, the Commission concluded that immediate action was essential to contain the disease, prevent its spread to domestic pigs and minimise economic damage. ASF is highly contagious and can spread through direct contact with infected animals or their secretions, as well as through contact with contaminated surfaces (such as carcasses). Infected wild boars contribute to its spread, but the effectiveness of removing carcasses depends on how quickly they are found and disposed of. Therefore, the response must be rapid, coordinated and science-based, following established disease control protocols. The immediate response and containment measures include establishing an infection zone (core Review: methods to find and date wild boar carcasses 64 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). varied. The best improvements to date have been made in relation to habitat preference and spatial analysis (literature). Several studies have analysed the spatial distribution of carcasses found in relation to environmental factors such as proximity to water sources, forest type and density, terrain, elevation and distance to roads and human settlements. This helps to identify areas where carcasses are most likely to be found. Spatial and epidemiological modelling can also predict the distribution of carcasses based on environmental variables or the expected number to be retrieved, depending on the epidemiological phase. This is important for efficiently allocating search resources and applying the exit strategy. Linked to the next point of discussion are studies analysing how quickly carcasses decompose in various habitats and how visible they are during the various stages of decomposition. This would help searchers know what to look for and where to look for carcasses. Finally, technology integration requires addressing drone technology specifically. The effectiveness of drones equipped with thermal imaging and high-resolution cameras for carcass detection can be evaluated by conducting field trials that compare drone-based searches with traditional ground searches. More specifically, studies are needed to optimise the use of trained dogs for carcass detection. This includes researching scent detection ranges, training protocols and the impact of environmental factors on canine performance. Table 5 below proposes some field experiments to determine the efficacy of wild boar carcass searches, which must be conducted in different areas and habitats across Europe where wild boars are found. Controlled experiments are needed to evaluate how effectively wild boar carcasses can be located in different conditions. These experiments should assess the efficiency of different search methods (human, canine, drone, etc.), environmental influences and detection success rates. Table 5. Proposal of some field experiments to determine the efficacy of wild boar carcass searches over different scenarios of Europe. 1. Controlled placement and recovery experiments Objective: Assess how different search methods perform in locating wild boar carcasses. Methodology: Place wild boar carcasses in various environments (forest, grassland, wetland). Use different search techniques: Human search teams (with and without tools like thermal imaging) Canine units trained for carcass detection Drones (thermal or multispectral imaging) Combinations Record detection rates, time taken, and environmental challenges. Expected Outcome: Identifies the most efficient search method under various conditions, which may help to make decision locally on best strategy 2. Impact of environmental conditions on detection Objective: Determine how weather, terrain, and vegetation affect search success. Methodology: Conduct searches in different seasons, weather conditions (rain, fog, snow) and terrain. Compare detection success in dense vs. open vegetation according to season and methods. Analyse also how the decomposition stage affects detection ease (fresh vs. advanced decay). This experiment can also be done for each method under different environments to evaluate how environmental conditions affect detection efficiency (for instance, for dogs, see below). Expected Outcome: Provides insights into optimal search conditions and limitations. Review: methods to find and date wild boar carcasses 65 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). 3. Effectiveness of drone-based searches for wild boar carcasses Objective: Evaluate drones for detecting wild boar carcasses compared to ground searches. Methodology: Test thermal imaging drones during day and night. Compare drone-detected vs. human-detected carcasses. Assess how altitude, flight speed, and sensor type affect detection, as well as decomposition status, and vegetation. Expected Outcome: Determines the viability of drones as a cost-effective alternative for large-scale carcass searches under specific conditions. 4. Evaluation of drone-based searches for wild boar carcasses: drone characteristics settings, development, and application of artificial intelligence models Objective: Evaluate best settings for drone-based detection, and development and validation of artificial intelligence models to automatize wild boar carcass detection Methodology: Experimental Design. 1. Selection of study Sites: Initially select one study area where define and test settings. Then, choose diverse landscapes and generate diverse images to train AI models. 2. Deployment of carcasses: Place wild boar carcasses (or synthetic carcass models) at varying distances, locations, covered by vegetation partially or not, different positions, within the study site and monitor over the decomposition process. Other species can be used to refine the AI model 3. Development of AI model 4. Validation with independent observations Equipment: Thermal imaging drones (detect heat differences, useful at night), multispectral drones (analyse vegetation changes due to decomposition), RGB optical drones (highresolution visible light cameras) Expected Outcomes: To optimize the efficacy of searching for wild boar carcasses. Identify best settings and functionalities for drone search strategies and automatize the process of detection, which will allow developing planned flights without the need of manual identification, speeding up the process. Optimize drone flight paths, altitudes, and imaging settings for maximum efficiency. 5. Role of scavengers in carcass disappearance Objective: Measure how quickly scavengers remove carcasses, impacting search accuracy. Methodology: Place motion-activated cameras near carcasses to monitor scavenger activity. Compare detection success in areas with high vs. low scavenger populations. Expected Outcome: Helps estimate the time window for effective carcass search before removal. Review: methods to find and date wild boar carcasses 66 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). 6. Forensic odour analysis for canine training Objective: Improve canine search accuracy by identifying key decomposition odours. Methodology: Analyse gas emissions from decaying wild boar using gas chromatography. Use results to refine canine training for improved scent recognition. Expected Outcome: Enhances the reliability of scent-detection dogs for carcass searches. Experiments with odour detection dogs for wild boar carcass searches Using detection dogs to locate wild boar carcasses is a promising approach, but their effectiveness depends on scent training, environmental factors, and search methodologies. Below are detailed experiments to assess and improve the efficacy of odour detection dogs in carcass searches. 7. Performance testing of trained dogs in different environments Objective: Evaluate how environmental conditions affect canine detection efficiency. Methodology: Testing Locations: Conduct searches in dense forests, grasslands, wetlands, and mountainous areas. Place carcasses at varying depths (surface vs. shallowly buried). Time-Based Testing: Conduct trials at different decomposition stages. Evaluate changes in detection success over time (0-48 hours, 1 week, 2 weeks, etc.). Weather & Temperature Variations: Conduct searches under different weather conditions (rain, fog, snow, heat). Measure scent dispersion and dog response under each condition. Expected Outcome: Determines optimal environments and conditions for search effectiveness. Helps adjust training for difficult terrain/weather conditions. 5.2. Wild boar carcass dating To our knowledge, no systematic attempt has been made to review the available information on dating wild boar carcasses. This review first evidenced that determining post-mortem interval (PMI) in wildlife carcasses, and in the case of wild boar in particular, is exceptionally difficult, presenting an even greater challenge than in human forensic cases. Secondly, aside from experimental studies (i.e. cases with known PMI), there is still a need to transfer and validate recent research experiences for the subsequent development of protocols and local application, given the lack of available adapted protocols/guidance on wild boar carcass dating for real-life cases. While known experiences from Central Europe can be adapted for use in other areas, local studies with similar methodology are required. Additionally, while the recent development of methods such as metabolomics-based approaches shows promise, it requires further development, as well as the appropriate facilities and expertise, to enable rapid assessment. 5.2.1 Overview of available studies and geographic distribution Review: methods to find and date wild boar carcasses 67 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). A total of 48 documents were identified, most of which were research papers. However, only 11 of these were selected for a detailed evaluation of methods on carcass statistics, as they referred to wild boar and/or had developed carcass dating methods that were later adopted for wild boar. All references were screened in detail and relevant information that could be directly transferred to the evaluation of carcass dating methods in wild boar was considered, including references to other species (wildlife, pigs, humans) and references incorporating carcass postmortem interval (PMI) estimations into epidemiological models. Only three of these eleven items were developed in ASF-infected areas, and the geographical distribution was mainly in Europe, with significant contributions from South Korea, where environmental conditions make the results transferable to Europe. Notably, four of the references were classified as experimental, meaning that wild boar carcasses were deployed for the purpose of evaluating the decay process and the post-mortem interval (PMI) was known. This is important for practical applications because it provides estimations of various parameters that can be determined or measured in wild boar carcasses over time and correlated with known PMI. Wild boar deaths in real ASF scenarios are often discovered late, with limited data on the immediate surrounding conditions at the time of death. This makes the application of common forensic entomology, pathology or temperature-based models difficult. The remaining seven cases originated from field observations and, although the exact PMI was unknown, they provided crucial information on the main circumstances and limitations to be addressed when dating wild boar cases in real scenarios. 5.2.2 Methodological approaches The sources supporting different methodological approaches were not particularly diverse. Of the 11 references, two were original in that they developed their own methodology to determine post-mortem interval (PMI) in wild boar carcasses. The remaining studies applied or adapted methodology that had already been described using human or animal models. This indicates that 'classical' forensic techniques, which are mostly based on macroscopic and entomological evidence, can be easily transferred, but their application requires adaptation to wild boar carcasses as well as to prevailing environmental and ecological conditions. Notably, one of the original cases refers to the first application of metabolomics to wild boar carcasses, specifically direct analysis in real time using DART-MS (Zacometti et al., 2025). Further studies are needed to relate metabolites to PMI, but this technique has shown its potential, especially given the low cost of the analysis and the simplicity and speed of sample preparation and analysis. Of the various methods employed for dating wild boar carcasses in the selected references, direct morphological examination of the decay/decomposition process was the most frequently used, either alone or in combination with other methods. This process typically involved categorising the carcass into different stages over time, which was not always entirely objective. Based on morphological evidence, the different phases of decomposition were determined variably according to the study. Examining visible stages of decomposition (e.g. fresh, bloated, active decay, advanced decay and skeletonisation) can provide clues about the time of death, although this method is less precise for wildlife due to the aforementioned unpredictable variables. The number of decomposition categories used also varied, with four categories being the most common. These categories can be represented by the following terminology: fresh, early decomposition, advanced decomposition and skeletonisation/mummification. This reveals variable categorisation and standards (flexible use Review: methods to find and date wild boar carcasses 68 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). of original sources), but this methodology can be harmonised if standards align well with the main primary sources in the literature, or if standards are established. It is important to note that we are referring to decomposition stages based mostly on macroscopic evidence; however, these stages are not universally associated with specific post-mortem intervals (PMI), as this depends on the specific context and conditions. For instance, a large wild boar may experience a prolonged bloating stage due to gas build-up, whereas a smaller animal may progress through this stage more quickly. These differences in the stages of decomposition can affect the timeframes used to estimate PMI. Three studies scored the decomposition process based on the methodology developed by Brooks et al. (2018), Megyesi et al. (2005) and Probst et al. (2020), the latter of which adapted the methodology for use with wild boar. This allows the use of a quantitative measure of decomposition to analyse the correspondence and account for the effects of the factors that determine carcass decay (i.e. predictive models of estimated post-mortem interval (PMI), see Müller et al. (2024)). Considering and analysing the effect of factors determining carcass decomposition/decay is therefore relevant. We found that different parameters were described in the selected literature on the decomposition process, with season and habitat/microhabitat conditions being the most frequently considered. Environmental temperature and the Accumulated Degree Days (ADD) score were also frequently considered, as was the impact of scavengers on the carcass decay process. The ADD score is a method used to estimate PMI by tracking carcass decomposition. This method relies on the accumulation of thermal energy over time, which is crucial for understanding the rate of decomposition. The ADD score is calculated by recording the previous daily average temperature. The maximum and minimum temperatures on the relevant days are recorded and the accumulation is determined over time. Daily degree days are then summed over the decomposition period to obtain the total ADD. This total reflects the cumulative thermal energy that has influenced the decomposition process. Using the ADD score enables researchers to standardise the decomposition process across different environments and conditions, facilitating comparison of results and more accurate estimation of PMI. To a lesser extent, body size (or age as a proxy) was parameterised throughout the decomposition process in the sampled studies. Next, based on the findings of this review, we indicate the main considerations that need to be accounted for when determining the PMI in wild boar: - There is extreme environmental variability. Wild boar exist in Europe in a variety of habitats, which exposes their carcasses to a wide range of conditions. Fluctuating temperatures, varying humidity levels and exposure to sunlight, shade or freezing conditions can all significantly impact decomposition rates. In some cases, the carcasses of wild animals may be partially preserved in cool, dry or submerged conditions, which can slow decomposition and make it harder to estimate post-mortem interval (PMI). This variability makes it nearly impossible to establish standardised decomposition timelines unless they are calibrated locally, and the time ranges determined will probably be wide, particularly as the decomposition process progresses. Interestingly, better precision can be obtained during the first months of PMI (based on experimental studies in Germany) (Probst et al., 2021; Rietz et al., 2023). An effective search strategy can facilitate access to carcasses at earlier stages and therefore PMI estimation can be an effective tool for determining the most recent infection event in the area. This is essential for the exit strategy, but as mentioned, requires implementing an efficient carcass search strategy. Characterising the age of the individual may provide clues as to the minimum PMI, given the seasonality of the species' births. - Specific decomposition. For wild boar, relevant differences in body size influence decomposition processes: larger animals decompose more slowly than smaller ones. To a lesser extent, fur influences decomposition processes, depending on the season and attitude. Review: methods to find and date wild boar carcasses 69 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). This species tends to develop abdominal adipocere (Forbes et al., 2005), a soft, white substance formed from fatty tissue in a decomposing body after death. It persists for a long time (even during skeletonization) and is difficult to date. Animals with thicker fat layers may decompose more slowly than those with leaner bodies. Extrapolating data from human studies, or even from domestic pigs, is often unreliable. The thick skin of wild boars affects the decomposition process compared to pigs. This affects how moisture and environmental elements interact with the carcass, slowing decomposition. - Unpredictable scavenger and insect activity: the extreme environmental variability in which wild boar exist in Europe determines unpredictable scavenger and insect activity, as well as cannibalistic behaviour. Wild boar carcasses are subject to intense scavenging by various animals, which disrupts decomposition patterns and removes or alters evidence. The presence of insect larvae, particularly blowflies, can be used to estimate the minimum post-mortem interval (PMI). However, the level of insect activity (forensic entomology) varies significantly depending on geographic location, season and local insect populations. Therefore, the timing and composition of insect colonisation can be highly unpredictable. This variability in insect activity means that this method is more accurate in controlled environments and experimental studies under certain conditions. 5.2.3 Current knowledge gaps The ability to carry out precise post-mortem investigations (PMI) on wild boar is also limited by the lack of research specific to this species. Forensic research has primarily focused on human remains and animal models, leaving a significant knowledge gap regarding wild boar decomposition and hindering the development of accurate post-mortem interval (PMI) estimation methods for diverse wildlife populations. Accessing and analysing wild boar carcasses in remote locations without (or with delayed) lab support, e.g. for entomological analysis, can further complicate the application of these methods. Overall, although methods are available to estimate PMI in wild boar, the accuracy and precision of these estimates can be limited by the complexity and variability of the factors involved. The scarcity of baseline decomposition data for wild boar — except for recent experimental data from Germany for classical methods and the thanatometabolomic approach from Italy — makes it difficult to create accurate PMI models or timelines for wild boar across Europe. Developing and validating new methods based on an understanding of the physical and chemical changes that occur post-mortem is promising, as is combining different approaches. Based on previous findings and discussions, we believe that determining PMI in wild boar requires various experiments and methods. These experiments often need to be conducted in various environmental settings to build a comprehensive understanding of PMI in the target species across Europe. The following are needed: - Decomposition studies. These experiments involve placing wildlife carcasses in controlled environments (e.g., climate-controlled chambers) to monitor decomposition under specific conditions (temperature, humidity). - Controlled environmental studies. This allows researchers to isolate and quantify the effects of individual environmental factors on decomposition rates. Field decomposition studies would be a priority, together with the application of new methodologies such as metabolomics alongside classical methods. These studies would involve observing decomposition in natural habitats, recording environmental data such as temperature, humidity and rainfall, and documenting the stages of decomposition. Such studies are essential for understanding the impact of real-world environmental variability on Review: methods to find and date wild boar carcasses 70 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). post-mortem interval (PMI) estimation. Regional experiments are needed to allow for better PMI estimation models that are adapted to specific habitats, environments, ecological characteristics and seasonal conditions. This will enable the standardisation of PMI estimation through controlled experiments, improve accuracy in real-world cases, and provide baseline data for forensic pathologists and ecologists dealing with wild boar carcasses. 6. Conclusions 6.1. Wild boar carcass search • Twenty years have passed since the last introduction of ASF in wild boar in Europe, and detailed information on strategies and best practices for finding wild boar carcasses and adapting these methodologies locally is difficult to access. Although the timely removal of wild boar carcasses following the detection of the first case is crucial, there is a notable lack of established protocols and practical guidance for the effective detection of carcasses, especially given the variety of approaches within individual European countries due to federal or autonomous administrative structures. • This scarcity of protocols and guidance on searching for wild boar carcasses indicates the need to make public and transfer local expertise across Europe and on focal outbreaks of ASF. Harmonising data collection and evaluating survey performance is essential in order to learn lessons and help standardise this activity. • Relevant research has been conducted in Central Europe in relation to wild boar carcass searches and dating. These studies must be tested and adapted further in different biogeographical and epidemiological scenarios to assess their efficiency in carcass search and carcass dating, and their adaptability to different scenarios in Europe. The general principles of deathbed choice by wild boar and the methodologies that can be used are relatively well known, favouring the adoption of such protocols. • In Europe, most of the literature on this topic comes from countries affected by ASF. Most national veterinary administrations responded that there is no systematic protocol for searching for wild boar carcasses. We advocate agreeing on and incorporating detailed guidance on wild boar carcass searches into the wild boar population control and monitoring plan that the Commission has requested from countries as part of the fight against ASF. • The priority criteria used in the literature we surveyed to select areas for wild boar carcass searches are mainly related to the increased risk of finding dead wild boars and the estimated ASF risk. The risk determined for the target infected area, its shape and size, and the design (e.g. systematic spatial grids versus habitat-driven) will significantly impact the efficiency of carcass retrieval. The optimal approach may involve integrating different strategies to maximise effectiveness. On the one hand, a habitat-based strategy prioritises searching in areas where wild boar carcasses are most likely to be found, based on ecological and behavioural knowledge. These strategies would be more efficient in targeted areas with known wild boar activity. Gridbased strategies, on the other hand, provide comprehensive coverage and are useful in areas where habitat data is less well known. Features usually considered for a habitat- Review: methods to find and date wild boar carcasses 71 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). based strategy include the presence of forests, proximity to water sources, forest types, terrain and areas with minimal human disturbance. • One important missing step in developing carcass search strategies based on past experience is that the performance of wild boar searches was hardly ever quantified, and even worse, the methods and metrics used were not comparable. The ratio of found to hidden carcasses is mostly unknown. • Another relevant pitfall of the currently available data is the scarcity of method comparisons, particularly fair comparisons under similar circumstances. • An essential aspect requiring guidance concerns the efforts required and the resources available to be deployed over time. The literature on this topic is limited and lacks detail, using different metrics. This has prevented comparisons being made between methods, strategies, areas and epidemiological scenarios, and has made it difficult to determine the real efficacy in terms of the proportion of carcasses found. The parameters provided here offer some guidance on determining the necessary human effort. • The main factors reported in the literature that may determine the applicability and performance of different wild boar carcass search protocols are of a different nature. These include natural determinants relating to wild boar ecology, the environment and climate, and how the search is organised at different stages, such as economic compensation for searchers and the means used, e.g. trained dogs and combination methods. Clearly, the relevance of different factors depends on the local scenario and the methods applied; even a given factor may diminish or increase efficacy under different circumstances. • Surveillance and search techniques, such as active ground searches by humans or aerial surveillance, are far from 100% effective in eliminating operator fatigue and other issues. While this review identified four main methods for the active detection of wild boar carcasses, an integrated approach could improve the efficiency and effectiveness of surveillance efforts, particularly in hard-to-reach areas: • Ground survey teams may work alongside other surveillance tools, such as drones equipped with thermal imaging cameras and carcass-detection dogs. • Specifically, patrolling by car over known or possible hotspots for wild boar activity or death beds (risk-based surveillance) complements a more systematic search by teams of beaters, drones and dogs. This is particularly useful for making an initial, preliminary estimation of the infected area, after which more systematic search activities can be developed. The first 72 hours are crucial for effective disease control, so targeted patrolling of relevant zones is a key priority during this period. • The use of specially trained dogs to search for carcasses is an effective tool for carcass detection, even in dense vegetation and when locating the remains of dead wild boar, such as single bones. Well-trained dogs are arguably the most portable and versatile scent detection tools currently available. However, their operational use in the field remains limited and the efficiency of odour detection can vary significantly between dogs. Appropriate biosecurity measures must also be considered when employing detection dogs. Review: methods to find and date wild boar carcasses 72 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). • Further integration and generalisation of drone technology in wildlife surveillance is promising yet still underutilised. For example, drones equipped with thermal imaging cameras have been used to monitor wild boar populations, improving surveillance and containment efforts in hard-to-reach areas while offering the potential for the rapid, efficient, and safe detection of wild boar carcasses. However, there is a need to develop this technology and drone-specific protocols beyond local application. • Searching for carcasses is time-consuming and labour-intensive, particularly in large or remote areas. Financial compensation provides a tangible incentive to motivate individuals to dedicate their time and effort to this task. • There is no universally agreed number of carcasses that must be found to guarantee eradication. Studies indicate that only a small percentage of wild boar carcasses are typically found in natural habitats, making eradication very difficult. Despite the limited resources available, repeated searches of the same areas aim to maximise carcass detection. Rather than focusing on a specific proportion, the emphasis is placed on maximising carcass removal in conjunction with other control measures. Continuous monitoring of wild boar carcasses in affected areas is also useful for determining the exit strategy, for which precise carcass dating is relevant. • We propose experimental areas requiring further development in order to gather applied reliable information to have elements of decision to determine the most efficient and cost-effective search strategies under different circumstances and contexts: • Comparative search experiments should compare the effectiveness of different methods, such as human search teams versus canine search teams, systematic grid searches versus targeted searches based on habitat analysis, and the use of drones with thermal imaging versus traditional ground searches. Researchers would measure the time taken, the area covered, and the number of carcasses found by each method. Any trial must be conducted in such a way that the results can be compared between zones, using similar (or interchangeable) metrics. Such an experiment could also be carried out under real-world conditions provided specific circumstances exist that prevent wild boar from entering the searched area (e.g. areas secured with wild boarproof fencing), thereby ensuring that no additional animals die within it and influence the carcass count relative to the initial baseline. • To quantify the probability of detecting a wild boar carcass within a given area. This involves placing known carcasses in the field and conducting repeated searches to determine the detection rate. Factors such as the stage of carcass decomposition, vegetation cover and terrain can be varied. Several studies have analysed the spatial distribution of carcasses found in relation to environmental factors such as proximity to water sources, forest type and density, terrain, elevation and distance to roads and human settlements. • Performance testing of trained dogs in different environments is required to evaluate how environmental conditions affect canine detection efficiency. This trial involves conducting searches in dense forests, grasslands, wetlands and mountainous areas for carcasses buried at different depths and stages of decomposition. • Technology integration requires addressing specifically drone technology. Evaluating the effectiveness of drones equipped with thermal imaging and high-resolution cameras for Review: methods to find and date wild boar carcasses 73 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). carcass detection involves conducting field trials to compare drone-based searches with ground searches. 6.2. Wild boar carcass dating • Determining post-mortem interval (PMI) in wildlife carcasses, and in the case of wild boar, is exceptionally difficult and presents a greater challenge. Apart from some experimental studies (i.e. known PMI), there are no validated protocols or detailed guidance on dating wild boar carcasses for real-life applications. Although known experiences from Central Europe can be adapted for use in other areas, regional studies with similar methodology are still required. • The recent development of methods such as metabolomics-based approaches is promising, but further development, as well as the appropriate facilities and expertise, is required for rapid assessment. Notably, an original case study refers to the first application of metabolomics in wild boar. • Scientific literature on forensic techniques, mostly based on macroscopic and entomological evidence, can be transferred to different scenarios in Europe, but prior validation is required to account for prevailing environmental and ecological conditions. Estimated post-mortem interval (PMI) still presented wide ranges on the basis of experimental studies, increasing as time elapsed since death. • Based on macroscopic evidence, the different phases of decomposition were determined variably according to the study, but they can potentially be harmonised. However, decomposition stages based mostly on macroscopic evidence cannot be universally associated with specific post-mortem intervals (PMI), as this depends on the specific context and conditions. • While several methods are available for estimating post-mortem interval (PMI) in wild boar, the accuracy and precision of these estimates can be limited by the complexity and variability of the factors involved. The most frequently considered factors impacting PMI were season, habitat and determinants of microhabitat conditions. Environmental temperature, and specifically Accumulated Degree Days (ADD), is a parameter that is often considered to affect the process of carcass decay. Body size (or age as a proxy) as well as insect activity and scavenger activity were considered relevant throughout the decomposition process in the sampled studies. • The main considerations that need to be accounted for when determining PMI in wild boar across Europe are: • Extreme environmental variability means that extrapolating data from studies in different areas/bioregions is probably unreliable. • Aspects related to specific decomposition processes in wild boar. • Extrapolating data from human studies, or even from studies of domesticated animals such as pigs, is also unreliable. • Unpredictable scavenger and insect activity, which varies by area/bioregion. • Accessing and analysing wild boar carcasses in remote locations often requires work to be done in the field without lab support (e.g. delayed entomological analysis). Review: methods to find and date wild boar carcasses 80 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Interview Interview Interview Interview Italy Research article First Outbreak of African Swine Fever in Sweden: Local Epidemiology, Surveillance, and Eradication Strategies Chenais, E et al. 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The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Annex 2. Carcass dating final selection (n=11) Type of docum ent Title Authors Journal Yea r Country Original or reproduc ed Reproduc ed from Scienti fic paper Unravelling the dispersal dynamics and ecological drivers of the African swine fever outbreak in Belgium Dellicour Simon et al. J Appl Ecol. 2020 202 0 Belgium R Brooks et al. 2018, Probst et al. 2020 Scienti fic paper First outbreak of Sfrican swine fever in Sweden: local epidemiology, surveillance, and eradication strategies Chenais Erika et al. Transboundary and Emerging Diseases 202 4 Sweden R Megyesi et al. 2005 Scienti fic paper Spatio-temporal epidemiology of the spread of African swine fever in wild boar and the role of environmental factors in South Korea Ito Satoshi et al. Viruses 2022, 14 (12), 2779 202 2 South Korea R Parsons HR. 2009, Probst et al. 2020. Keough et al, 17. Scienti fic paper drone-based thermal imaging in the detection of wildlife carcasses and disease management Janine Rietz et al. Transboundary and Emerging DiseasesVolume 2023, Article ID 5517000, 202 3 Germany R Goff 2009, Anderson and Van Laerhove n 1996 Scienti fic paper Estimating the postmortem interval of wild boar carcasses Carolina Probs et el. Vet Sci 2020 Jan 5;7(1):6. 202 0 Germany R Megyesi et al. 2005 Review: methods to find and date wild boar carcasses 85 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Scienti fic paper Season, decay stage, habitat, temperature and carrion beetles allow estimating the post-mortem interval of wild boar carcasses Müller et al. Ecological Solutions and Evidence 5(1):12305 202 4 Germany R Goff 2009, Anderson and Van Laerhove n 1996, Von Hoerman n et al. 2018 Scienti fic paper Thanatometabolo mics in wildlife: identifying potential metabolic markers of postmortem intervals in wild boars by direct analysis in real time High Resolution Mass Spectrometry (Dart-Hrms) Zacometti, Carmela et al. Microchemical Journal 212:113 296 202 4 Italy O Scienti fic paper Wildlife as potential vectors of African swine fever virus Lim, Sang Jin et al. Journal of Forest and Environmental Science, Vol. 38, No. 1, pp. 55-63, March, 2022 202 2 South Korea R Parsons HR. 2009, Probst et al. 2020; Keough et al. 17. Scienti fic paper Functional differences in scavenger communities and the speed of carcass decomposition Wenting, Elke et al. Ecology and Evolution, 2022;12:e8576 202 2 Netherla nds O Scienti fic paper A preliminary investigation into the decomposition rate of wild boar carcasses in forest habitats HeeKyeung Cho et al. J. Prev. Vet. Med. 2021; 45(1): 44-52. 202 1 South Korea R Megyesi et al. 2005 Review: methods to find and date wild boar carcasses 86 www.efsa.europa.eu/publications EFSA Supporting publication 2025 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the author(s). Other output Grey literature: notes about the DEATHBOARS project Istituto Zooprofilat tico Sperimenta le delle Venezie (IZSVe) Presentation 202 4 Italy R Pittner et al. 2020, Probst et al. 2020