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In 2007 African swine fever (ASF) arrived at a Black Sea harbour in Georgia and in 2014 the infection reached the European Union (EU), where it still expands its territory. ASF is a fatal viral disease affecting domestic pigs and wild boar of all ages with clinical presentations ranging from per-acute to chronic disease, including apparently asymptomatic courses. Until the detection of the first case inside the EU, infections in the current epidemic were mainly seen among pig farms with generally low biosecurity, and with incidental spill over to the wild boar population. In the EU, however, the infection survived locally in the wild boar population independently from outbreaks in domestic pigs, with a steady and low prevalence. Apart from the wild boar population and the habitat, the current epidemic recognizes humans as the main responsible for both long distance transmission and virus introduction in the domestic pig farms. This underlines the importance to include social science when planning ASF-prevention, −control, or -eradication measures. Based on experiences, knowledge and data gained from the current epidemic this review highlights some recent developments in the epidemiological understanding of ASF, especially concerning the role of wild boar and their habitats in ASF epidemiology. In this regard, the qualities of three epidemiological traits: contagiousity, tenacity, and case fatality rate, and their impact on ASF persistence and transmission are especially discussed.

African swine fever vaccines could pose risk of causing disease and spreading the virus further An epidemic of African swine fever (ASF), a lethal viral hemorrhagic disease of swine, is devastating pig production in Asia and is a global threat. The ASF virus (ASFV) reached the European Union (EU) in 2014, affecting pig production. ASFV continues to spread through wild boar ( Sus scrofa ), which form interconnected populations across Europe and which maintain the infection and can cause infection in pigs. A vaccine is not yet available and is urgently needed, both for pigs and wild boar. Live attenuated virus (LAV) vaccines are the most promising way forward in the short term ( 1 ), and recent advances have been made in constructing gene-deleted LAV vaccines. Naturally attenuated LAVs have also been shown to confer protection as vaccines in pigs and wild boar. However, previous experience with vaccination failures using naturally attenuated LAVs emphasizes the need for caution because of safety concerns.

This study was funded by Vetenskapsrådet (https://www.vr.se/), Award Number 2017-05518. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

In 2023, 14 Member States were affected by African swine fever (ASF), including Croatia and Sweden where ASF emerged (wild boar outbreaks only) and Greece where ASF re‐emerged after being free since 2021. The number of ASF outbreaks among domestic pigs in the EU was five times higher than in 2022, reaching a similar magnitude to that in 2019. This was predominantly driven by the introduction and subsequent spread of ASF in Croatia and its resurgence in Romania, representing 96% of the EU outbreaks. ASF outbreaks in domestic pigs were clearly seasonal in all countries, with 88% of outbreaks reported between July and October. Most of the ASF outbreaks among domestic pigs were detected through clinical suspicion (94%), followed by tracing from affected establishments (3%), and the weekly testing of at least two dead pigs in establishments (3%). In wild boar, a 10% increase in the number of notified outbreaks was observed in the EU in comparison with 2022, with considerable variations between countries. A winter peak was observed only in Poland, Slovakia and Hungary. The epidemiological situation in wild boar improved in Germany and Hungary, as suggested by the decrease in the number of outbreaks and in the proportions of PCR‐positive samples from dead wild boar. Overall, 31% of wild boar carcasses found during passive surveillance tested positive by PCR, representing 69% of the ASF outbreaks in wild boar in the EU. In contrast, 0.4% of hunted wild boar tested positive, representing 31% of the outbreaks. Despite the introduction of ASF into new countries and the increase in the number of outbreaks, the size of restricted zones in the EU remained stable, due to the highly clustered outbreaks in Croatia, and the reduction of restricted zones in Poland, Slovakia and Bulgaria (in domestic pigs), and Hungary (in wild boar).

This report provides an update of the epidemiology of African swine fever (ASF) in the European Union during the period November 2018 to October 2019. In this period, ASF has been confirmed in Slovakia, whereas Czechia became officially ASF‐free in March 2019, bringing the number of affected countries in the EU to nine. The report provides a narrative update of the situation in the different countries and an analysis of the temporal and spatial patterns of the disease. There has been no increase in the proportion of seropositive hunted wild boar in the affected areas. In hunted animals, the proportions of wild boar testing polymerase chain reaction‐positive and enzyme‐linked immunosorbent assay‐positive has remained low (< 0.05). In addition to the obvious seasonal peak in summer in domestic pigs, seasonality of ASF in wild boar was statistically confirmed. A network analysis demonstrated that the median velocity of the natural propagation of the disease in wild boar populations was between 2.9 and 11.7 km/year. Human‐mediated spread, both in pigs and wild boar, however, remains important. Several wild boar‐ and domestic pig‐related risk factors for ASF occurrence in non‐commercial farms in Romania were identified with a case–control study. This report also updates an extensive literature review on control measures to stop the spread of the disease in wild boar and on measures to separate wild boar populations. Several new studies have been identified in this reporting period, but these did not alter the conclusions of the previous reporting period. Field experience with the use of fences as part of the control strategy deployed in the Belgian focal outbreak of ASF in wild boar is described. So far, the measures have proven effective to keep ASF virus inside the affected area. This strategy included a combination of different measures, namely zoning, carcass removal, a complete feeding ban, specific hunting regulations and depopulation actions depending on the zone, a partial ban of people and logging, and setting up a network of concentric fences.

Between 29 April and 23 June 2023, highly pathogenic avian influenza (HPAI) A(H5N1) virus (clade 2.3.4.4b) outbreaks were reported in domestic (98) and wild (634) birds across 25 countries in Europe. A cluster of outbreaks in mulard ducks for foie gras production was concentrated in Southwest France, whereas the overall A(H5N1) situation in poultry in Europe and worldwide has eased. In wild birds, black‐headed gulls and several new seabird species, mostly gulls and terns (e.g. sandwich terns), were heavily affected, with increased mortality being observed in both adults and juveniles after hatching. Compared to the same period last year, dead seabirds have been increasingly found inland and not only along European coastlines. As regards mammals, A(H5N1) virus was identified in 24 domestic cats and one caracal in Poland between 10 and 30 June 2023. Affected animals showed neurological and respiratory signs, sometimes mortality, and were widely scattered across nine voivodeships in the country. All cases are genetically closely related and identified viruses cluster with viruses detected in poultry (since October 2022, but now only sporadic) and wild birds (December 2022–January 2023) in the past. Uncertainties still exist around their possible source of infection, with no feline‐to‐feline or feline‐to‐human transmission reported so far. Since 10 May 2023 and as of 4 July 2023, two A(H5N1) clade 2.3.4.4b virus detections in humans were reported from the United Kingdom, and two A(H9N2) and one A(H5N6) human infections in China. In addition, one person infected with A(H3N8) in China has died. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe remains low for the general population in the EU/EEA, low to moderate for occupationally or otherwise exposed people to infected birds or mammals (wild or domesticated).

Between 2 December 2023 and 15 March 2024, highly pathogenic avian influenza (HPAI) A(H5) outbreaks were reported in domestic (227) and wild (414) birds across 26 countries in Europe. Compared to previous years, although still widespread, the overall number of HPAI virus detections in birds was significantly lower, among other reasons, possibly due to some level of flock immunity in previously affected wild bird species, resulting in reduced contamination of the environment, and a different composition of circulating A(H5N1) genotypes. Most HPAI outbreaks reported in poultry were primary outbreaks following the introduction of the virus by wild birds. Outside Europe, the majority of outbreaks in poultry were still clustered in North America, while the spread of A(H5) to more naïve wild bird populations on mainland Antarctica is of particular concern. For mammals, A(H5N5) was reported for the first time in Europe, while goat kids in the United States of America represented the first natural A(H5N1) infection in ruminants. Since the last report and as of 12 March 2024, five human avian influenza A(H5N1) infections, including one death, three of which were clade 2.3.2.1c viruses, have been reported by Cambodia. China has reported two human infections, including one fatal case, with avian influenza A(H5N6), four human infections with avian influenza A(H9N2) and one fatal case with co‐infection of seasonal influenza A(H3N2) and avian influenza A(H10N5). The latter case was the first documented human infection with avian influenza A(H10N5). Human infections with avian influenza remain rare and no sustained human‐to‐human infection has been observed. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe remains low for the general population in the EU/EEA. The risk of infection remains low to moderate for those occupationally or otherwise exposed to infected animals.

African swine fever (ASF) is a devastating viral disease that affects domestic pigs ( Sus scrofa domesticus ) and European wild boar ( Sus scrofa scrofa ). A previous study indicated that wild boar were more susceptible to ASF than pigs, with shorter incubation periods and earlier onset of the disease. This follow-up study aims to compare the pathogenesis and progression of the disease between the two subspecies during the early and late stages of infection following intranasal inoculation with the highly virulent genotype II strain ‘Armenia 2007’. Histopathological changes and viral antigen distribution by immunohistochemistry (IHC) were assessed over time following intranasal inoculation. Viral antigen and histological changes were detected earlier in wild boar than in pigs. In wild boar, the medial retropharyngeal (MRPLN) and submandibular lymph nodes were among the earliest sites of virus replication from 3 days post-infection (dpi), with widespread dissemination occurring by 5 dpi. In pigs, the viral antigen was first detected in the MRPLN at 5 dpi. At the humane endpoint, which occurred at 6 dpi in wild boar and 9 dpi in pigs, virus antigen and histopathological scores were lower in wild boar than in pigs, even though the appearance and increase of viral antigen in tissues, onset and development of lesions and humane endpoint occurred earlier in the former. The lower severity and lesser extent of lesions in wild boar suggest lower tolerance of tissue damage prior to reaching the humane endpoint, demonstrating their greater susceptibility to and lower resistance against ASFV.

This report presents the epidemiological analysis of African swine fever (ASF) during 2022 based on the surveillance and pig population data submitted by the European Union (EU) affected countries and one neighbouring country. Coinciding with regulatory changes and an important decrease in ASF outbreaks in 2022 in the EU, the number of domestic pig samples tested as part of active surveillance decreased by 80%, while the number of samples from passive surveillance almost doubled compared with 2021. Most outbreaks among domestic pigs in the EU were detected by testing clinical suspicions (93% of outbreaks), followed by tracing activities (5%) and weekly testing of the first two dead pigs per establishment (2%). Although most of the wild boar samples came from hunted animals, the probability of detecting PCR‐positive animals was much higher in wild boar found dead. The ASF outbreaks among domestic pigs in the EU decreased by 79% while a decrease of 40% in the wild boar cases was observed in comparison with 2021. This was strongly marked in Romania, Poland and Bulgaria, with a reduction of 50–80% compared with 2021. In many countries, an important decrease in the number of pig establishments was observed, especially of small establishments with fewer than 100 pigs. The regional between farm incidence and proportion of pigs lost due to ASF in the EU was in general very low (average of 1%) apart from some regions in Romania. The impact of ASF on wild boar populations was variable, with a decline in wild boar abundance observed in certain countries versus a stable or even increased population after ASF introduction. This supports the negative relationship observed in this report between the proportion of the country with restricted zones due to ASF in wild boar and wild boar hunting bags. This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2023.EN-8029/full

Between 7 December 2024 and 7 March 2025, 743 highly pathogenic avian influenza (HPAI) A(H5) virus detections were reported in domestic (239) and wild (504) birds across 31 countries in Europe. HPAI A(H5N1) virus detections were predominant and mainly located in central, western and south‐eastern Europe. Most HPAI A(H5) virus detections in wild birds concerned waterfowl, particularly mute swans, barnacle geese and greylag geese. Limited secondary spread was observed among the poultry outbreaks, and outdoor poultry access remained an important risk factor at the interface between wild and domestic birds. HPAI A(H5N5) outbreaks occurred only in wild birds and were increasingly reported in waterfowl. For the first time since spring 2024, several HPAI virus detections were reported in domestic cats and wild carnivores in Europe. In the United States of America (USA), the number of dairy cattle farms reportedly affected rose to almost 1000 in 17 States, and a different HPAI A(H5N1) virus genotype (D1.1) was reported in this species. Between 12 December 2024 and 7 March 2025, 22 new cases of avian influenza virus infection in humans were reported in the USA (12 A(H5) cases), Cambodia (two A(H5N1) cases), United Kingdom (one A(H5N1) case), and China (six A(H9N2) cases and one A(H10N3) case). Most of the A(H5) human cases (93%, n = 14/15) had reported exposure to poultry or dairy cattle prior to avian influenza virus detection or onset of illness. Considering the widespread circulation of avian influenza viruses in animal populations, human infections with avian influenza viruses remain infrequent. No evidence of human‐to‐human transmission has been documented during the reporting period. The risk of infection with the avian A(H5) influenza viruses of clade 2.3.4.4b currently circulating in Europe remains low for the general public in the European Union/European Economic Area (EU/EEA). The risk of infection remains low‐to‐moderate for those occupationally or otherwise exposed to infected animals or contaminated environments.