An Update on African Swine Fever

A special issue of Pathogens (ISSN 2076-0817). This special issue belongs to the section "Viral Pathogens".

Deadline for manuscript submissions: closed (30 September 2023) | Viewed by 32792

Special Issue Editors


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Guest Editor
Research Institute of Food Safety, Animal Health and Environment "BIOR", Riga, Latvia
Interests: African swine fever; epidemiology; surveillance; disease prevention and control measures; outbreak investigation

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Guest Editor
Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany
Interests: control and eradication of transboundary animal diseases; virology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

We invite you to contribute to the Special Issue “An Update on African Swine Fever”.

The current African swine fever (ASF) epidemic started in Georgia where ASF virus genotype II was introduced in 2007. During the last 15 years, it spread further to Europe and Asia heavily affecting the wild boar population and domestic pig farms. In large ASF affected areas the wild boar is considered as the main driver and reservoir of ASF virus thus presenting the permanent threat to pig farming industry. The spread of ASF continues due to the lack of effective control measures, especially in wild boar population. Despite the biosecurity measures are suggested to prevent ASF introduction in domestic pigs, thousands of pig farms are affected by ASF annually. While waiting for the safe and effective vaccine against ASF, the preventive and control measures should be strengthened.   

Suggested topics for this Special Issue include, but are not limited to:

  • virus maintenance in the wild boar population and environment;
  • virus transmission pathways from wild boar to domestic pigs;
  • effective ASF prevention and control methods in wild boar;
  • surveillance strategies for ASF endemic countries;
  • prevention of ASF introduction in domestic pig farms (biosecurity measures);
  • development of safe and effective vaccine.

Based on your expertise in the field, we think you could make an excellent contribution to the Special Issue “An Update on African Swine Fever”.

Dr. Edvins Olsevskis
Dr. Klaus Robert Depner
Guest Editors

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Keywords

  • African swine fever
  • epidemiology
  • prevention and control measures
  • vaccine
  • biosecurity

Published Papers (15 papers)

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Research

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12 pages, 2783 KiB  
Article
Evaluation of the Risk of African Swine Fever Virus Transmission at the Interface between Feral and Domestic Pigs in Lombardy, with a View to Establishing Preventive Measures for Domestic Pigs
by Stefania Calò, Marco Tironi, Veronica Cappa, Alessandra Scaburri, Stefano Francesco Perna, Mario Chiari, Massimo Marracci and Silvia Bellini
Pathogens 2023, 12(12), 1462; https://doi.org/10.3390/pathogens12121462 - 18 Dec 2023
Viewed by 1082
Abstract
African swine fever (ASF) continues to spread worldwide, and has reached multiple countries across Asia, the Caribbean, Europe, and the Pacific, representing a serious economic burden threatening pig health and welfare, as well as food security. The disease affects domestic pigs and wild [...] Read more.
African swine fever (ASF) continues to spread worldwide, and has reached multiple countries across Asia, the Caribbean, Europe, and the Pacific, representing a serious economic burden threatening pig health and welfare, as well as food security. The disease affects domestic pigs and wild boar, and in several European countries the disease is endemic in wild boars. The lack of vaccines or effective treatments highlights the importance of effective control measures used to keep domestic and feral pigs separated to prevent the spread of the virus. However, the study of the livestock–wildlife interface is quite complex and has many aspects to consider, including the uncertainty of wild-boar population data. In this study, we determined the risk of spread of the ASF virus at the interface between domestic pigs and wild boars using indicators that can indirectly indicate the presence of wild boars in order to target specific control measures in the highest risk areas. The results of the study were compared with those obtained by Pittiglio, in which the population data for wild boars was estimated using a geostatistical method and similar results were obtained. However, the present study used specific information relating to the wild-boar population and this allowed us to use fewer variables. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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14 pages, 2629 KiB  
Article
Estimating the Directional Spread of Epidemics in Their Early Stages Using a Simple Regression Approach: A Study on African Swine Fever in Northern Italy
by Vincenzo Gervasi, Marco Sordilli, Federica Loi and Vittorio Guberti
Pathogens 2023, 12(6), 812; https://doi.org/10.3390/pathogens12060812 - 07 Jun 2023
Cited by 1 | Viewed by 1112
Abstract
The early identification of the spreading patterns of an epidemic infectious disease is an important first step towards the adoption of effective interventions. We developed a simple regression-based method to estimate the directional speed of a disease’s spread, which can be easily applied [...] Read more.
The early identification of the spreading patterns of an epidemic infectious disease is an important first step towards the adoption of effective interventions. We developed a simple regression-based method to estimate the directional speed of a disease’s spread, which can be easily applied with a limited dataset. We tested the method using simulation tools, then applied it on a real case study of an African Swine Fever (ASF) outbreak identified in late 2021 in northwestern Italy. Simulations showed that, when carcass detection rates were <0.1, the model produced negatively biased estimates of the ASF-affected area, with the average bias being about −10%. When detection rates were >0.1, the model produced asymptotically unbiased and progressively more predictable estimates. The model produced rather different estimates of ASF’s spreading speed in different directions of northern Italy, with the average speed ranging from 33 to 90 m/day. The resulting ASF-infected areas of the outbreak were estimated to be 2216 km2, about 80% bigger than the ones identified only thorough field-collected carcasses. Additionally, we estimated that the actual initial date of the ASF outbreak was 145 days earlier than the day of first notification. We recommend the use of this or similar inferential tools as a quick, initial way to assess an epidemic’s patterns in its early stages and inform quick and timely management actions. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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6 pages, 547 KiB  
Communication
Do Seropositive Wild Boars Pose a Risk for the Spread of African Swine Fever? Analysis of Field Data from Latvia and Lithuania
by Edvīns Oļševskis, Marius Masiulis, Mārtiņš Seržants, Kristīne Lamberga, Žanete Šteingolde, Laura Krivko, Svetlana Cvetkova, Jūratė Buitkuvienė, Simona Pilevičienė, Laura Zani, Nicolai Denzin and Klaus Depner
Pathogens 2023, 12(5), 723; https://doi.org/10.3390/pathogens12050723 - 17 May 2023
Cited by 2 | Viewed by 1342
Abstract
In 2020, ASF occurred in wild boars throughout Latvia and Lithuania, and more than 21,500 animals were hunted and tested for the presence of the virus genome and antibodies in the framework of routine disease surveillance. The aim of our study was to [...] Read more.
In 2020, ASF occurred in wild boars throughout Latvia and Lithuania, and more than 21,500 animals were hunted and tested for the presence of the virus genome and antibodies in the framework of routine disease surveillance. The aim of our study was to re-examine hunted wild boars that tested positive for the antibodies and negative for the virus genome in the blood (n = 244) and to see if the virus genome can still be found in the bone marrow, as an indicator of virus persistence in the animal. Via this approach, we intended to answer the question of whether seropositive animals play a role in the spread of the disease. In total, 2 seropositive animals out of 244 were found to be positive for the ASF virus genome in the bone marrow. The results indicate that seropositive animals, which theoretically could also be virus shedders, can hardly be found in the field and thus do not play an epidemiological role regarding virus perpetuation, at least not in the wild boar populations we studied. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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13 pages, 4043 KiB  
Article
Static Aerated Composting of African Swine Fever Virus-Infected Swine Carcasses with Rice Hulls and Sawdust
by Mark Hutchinson, Hoang Minh Duc, Gary A. Flory, Pham Hong Ngan, Hoang Minh Son, Tran Thi Khanh Hoa, Nguyen Thi Lan, Dale W. Rozeboom, Marta D. Remmenga, Matthew Vuolo, Robert Miknis, Lori P. Miller, Amira Burns and Renée Flory
Pathogens 2023, 12(5), 721; https://doi.org/10.3390/pathogens12050721 - 16 May 2023
Cited by 1 | Viewed by 1440
Abstract
Identifying and ensuring the inactivation of the African Swine Fever virus in deadstock is a gap in the swine industry’s knowledge and response capabilities. The results of our study demonstrate that ASFv in deadstock was inactivated using static aerated composting as the carcass [...] Read more.
Identifying and ensuring the inactivation of the African Swine Fever virus in deadstock is a gap in the swine industry’s knowledge and response capabilities. The results of our study demonstrate that ASFv in deadstock was inactivated using static aerated composting as the carcass disposal method. Replicated compost piles with whole market hogs and two different carbon sources were constructed. In-situ bags containing ASFv-infected spleen tissue were placed alongside each of the carcasses and throughout the pile. The bags were extracted at days 0, 1, 3, 7, 14, 28, 56, and 144 for ASFv detection and isolation. Real-time PCR results showed that DNA of ASFv was detected in all samples tested on day 28. The virus concentration identified through virus isolation was found to be below the detection limit by day 3 in rice hulls and by day 7 in sawdust. Given the slope of the decay, near-zero concentration with 99.9% confidence occurred at 5.0 days in rice hulls and at 6.4 days in sawdust. Additionally, the result of virus isolation also showed that the virus in bone marrow samples collected at 28 days was inactivated. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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10 pages, 2752 KiB  
Article
Differentiation of African Swine Fever Virus Strains Isolated in Estonia by Multiple Genetic Markers
by Annika Vilem, Imbi Nurmoja, Lea Tummeleht and Arvo Viltrop
Pathogens 2023, 12(5), 720; https://doi.org/10.3390/pathogens12050720 - 16 May 2023
Cited by 3 | Viewed by 1190
Abstract
The African swine fever virus (ASFV) was first detected in Estonia, in September 2014. In the subsequent three years, the virus spread explosively all over the country. Only one county, the island of Hiiumaa, remained free of the disease. Due to the drastic [...] Read more.
The African swine fever virus (ASFV) was first detected in Estonia, in September 2014. In the subsequent three years, the virus spread explosively all over the country. Only one county, the island of Hiiumaa, remained free of the disease. Due to the drastic decrease in the wild boar population in the period of 2015–2018, the number of ASFV-positive cases among wild boar decreased substantially. From the beginning of 2019 to the autumn of 2020, no ASFV-positive wild boar or domestic pigs were detected in Estonia. A new occurrence of ASFV was detected in August 2020, and by the end of 2022, ASFV had been confirmed in seven counties in Estonia. Investigations into proven molecular markers, such as IGR I73R/I329L, MGF505-5R, K145R, O174L, and B602L, were performed with the aim of clarifying whether these cases of ASFV were new entries or remnants of previous epidemics. The sequences from the period of 2014–2022 were compared to the Georgia 2007/1 reference sequence and the variant strains present in Europe. The results indicated that not all the molecular markers of the virus successfully used in other geographical regions were suitable for tracing the spread of ASFV in Estonia. Only the B602L-gene analysis enabled us to place the ASFV isolates spreading in 2020–2022 into two epidemiologically different clusters. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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13 pages, 2773 KiB  
Article
Semi-Quantitative Risk Assessment of African Swine Fever Virus Introduction in Outdoor Pig Farms
by Alessia Rusinà, Francesco Valentini, Annalisa Scollo, Giorgio Franceschini, Sara Salvato, Veronica Cappa, Alessandro Bellato, Alessandro Mannelli and Silvia Bellini
Pathogens 2023, 12(5), 709; https://doi.org/10.3390/pathogens12050709 - 12 May 2023
Viewed by 1153
Abstract
In a previous study, a semi-quantitative risk assessment was developed to rank pig holdings in terms of likelihood of introducing African swine fever virus (ASFV) by assessing their compliance with biosecurity and exposure to geographical risk factors. The method was initially developed for [...] Read more.
In a previous study, a semi-quantitative risk assessment was developed to rank pig holdings in terms of likelihood of introducing African swine fever virus (ASFV) by assessing their compliance with biosecurity and exposure to geographical risk factors. The method was initially developed for confined pig holdings, but given that ASF is endemic in wild boar of several countries, we modified the approach to make it suitable for free-range farms as well. In the current study, a total of 41 outdoor pig farms were assessed in an area where exposure to wild boar was generally high (density from 2.3 to 10.3 wild boar per Km2). As expected, non-compliance with biosecurity measures was frequent in outdoor farms, and the frequency of non-compliance indicated that the absence of adequate separation of pigs from the external environment was the major weakness in the farms assessed. In 46.3% of them, there was no fence or, if present, it was not adequate to avoid contact with wild boar. However, the approach adopted proved to be suitable for identifying intervention priorities to mitigate the risk of ASFV spread in free-range pig herds and for identifying the weaknesses of individual farms, as recommended by EFSA in 2021, which suggests implementing tools to improve biosecurity by favoring higher-risk farms. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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8 pages, 2539 KiB  
Communication
African Swine Fever Outbreak in an Enclosed Wild Boar Hunting Ground in Serbia
by Jasna Prodanov-Radulović, Jovan Mirčeta, Biljana Djurdjević, Sava Lazić, Sanja Aleksić-Kovačević, Jelena Petrović and Vladimir Polaček
Pathogens 2023, 12(5), 691; https://doi.org/10.3390/pathogens12050691 - 09 May 2023
Cited by 2 | Viewed by 1274
Abstract
African swine fever (ASF) has been detected in many European countries since its introduction in Georgia in 2007. Serbia suffered its first case of ASF in the domestic pig population in 2019. At the beginning of 2020, ASF was detected in wild boars [...] Read more.
African swine fever (ASF) has been detected in many European countries since its introduction in Georgia in 2007. Serbia suffered its first case of ASF in the domestic pig population in 2019. At the beginning of 2020, ASF was detected in wild boars in open hunting grounds in the southeastern region of the country in districts along the country’s borders with Romania and Bulgaria. Since then, all ASF outbreaks in wild boar were clustered in the population located in the same bordering areas. Despite the newly implemented biosecurity protocols for hunters in 2019, ASF was detected for the first time in June 2021 in the wild boar population located in an enclosed hunting ground in the northeast region of the country. In this study, we reported the first ASF outbreak in a wild boar population located in an enclosed hunting ground in close proximity to the Serbian–Romanian border. The epizootiological data on the field investigation of the ASF outbreak, with descriptions of the clinical signs and gross pathological lesions detected, including the total number as well as the estimated age, sex, and postmortem interval, were analyzed. Clinical signs were detected only in nine diseased wild boars, while in total, 149 carcasses were found in the open and enclosed part of the hunting ground. In addition, 99 carcasses from which samples (parts of spleen or long bones) were collected for molecular diagnostics (RT-PCR) were confirmed as ASF-positive. The results of the epidemiological investigations indicate the central role of wild boar movements as well as the constant risk of human-related activities in the countries bordering area. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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15 pages, 6114 KiB  
Article
Viability of African Swine Fever Virus with the Shallow Burial with Carbon Carcass Disposal Method
by Hoang Minh Duc, Mark Hutchinson, Gary A. Flory, Pham Hong Ngan, Hoang Minh Son, Le Van Hung, Tran Thi Khanh Hoa, Nguyen Thi Lan, Truong Quang Lam, Dale Rozeboom, Marta D. Remmenga, Matthew Vuolo, Robert Miknis, Amira Burns and Renée Flory
Pathogens 2023, 12(4), 628; https://doi.org/10.3390/pathogens12040628 - 21 Apr 2023
Viewed by 1861
Abstract
African swine fever (ASF) is a highly contagious swine disease with high mortality. In many countries, culling pigs infected and exposed to the ASF virus is mandatory to control the disease, which poses a real challenge in the disposal of large numbers of [...] Read more.
African swine fever (ASF) is a highly contagious swine disease with high mortality. In many countries, culling pigs infected and exposed to the ASF virus is mandatory to control the disease, which poses a real challenge in the disposal of large numbers of carcasses during ASF outbreaks. Shallow burial with carbon (SBC) Thanks ew mortality disposal method developed from deep burial and composting. The present study investigates the effectiveness of SBC in disposing of ASF virus-infected pigs. The real-time PCR results showed that DNA of the ASF virus was still detected in bone marrow samples on day 56, while the virus isolation test revealed that the infectious ASF virus was destroyed in both spleen and bone marrow samples on day 5. Interestingly, decomposition was found to occur rapidly in these shallow burial pits. On day 144, only large bones were found in the burial pit. In general, the results of this study indicated that SBC is a potential method for the disposal of ASF-infected carcasses; however, further studies are needed to provide more scientific evidence for the efficacy of SBC in different environment conditions. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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10 pages, 1761 KiB  
Article
Evaluation of Biosecurity Measures in Pig Holdings in Slovenia as a Risk Assessment for the Introduction of African Swine Fever Virus
by Jan Plut, Tanja Knific, Irena Golinar Oven, Gorazd Vengušt and Marina Štukelj
Pathogens 2023, 12(3), 434; https://doi.org/10.3390/pathogens12030434 - 09 Mar 2023
Cited by 2 | Viewed by 1529
Abstract
African Swine Fever (ASF) is persistently spreading and hindering pork production in Europe. Slovenia is one of the last countries in Central Europe without a confirmed ASF case in domestic pigs or in wild boar. The aim of this study was to assess [...] Read more.
African Swine Fever (ASF) is persistently spreading and hindering pork production in Europe. Slovenia is one of the last countries in Central Europe without a confirmed ASF case in domestic pigs or in wild boar. The aim of this study was to assess the current biosecurity implementation on different types of pig farms. Internal and external biosecurity status was determined in 17 commercial (CF), 15 non-commercial (NC), and 15 outdoor (O) farms. Data were collected using the Biocheck.UGent questionnaire and assessed in combination with the latest information on the wild boar population in Slovenia. Biosecurity was compared between farm types based on the assessment of 12 subcategories. Statistically significant differences (p < 0.05) were found in six subcategories: (i) purchase of pigs and semen, (ii) visitors and farmworkers, (iii) vermin and bird control, (iv) finishing unit, (v) measures between compartments and use of equipment, and (vi) cleaning and disinfection. The highest total biosecurity score (0–100%) was determined on CF with 64.59 ± 16.47%, followed by NC with 55.73 ± 10.67%, and O with 48.47 ± 8.20%. The density of the wild boar population was estimated from the number of wild boars per km2 per year, with 3 or more hunted wild boars per unit representing the highest density. Geolocation of farms on the wild boar population map showed that two O farms are at high risk and seven farms (1 O, 5 NC, and 1 CF) are at medium risk for disease transmission from wild to domestic pigs. Biosecurity measures must be tightened in some subcategories, especially in areas with a high density of wild boar. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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11 pages, 2532 KiB  
Article
Composting of Wild Boar Carcasses in Lithuania Leads to Inactivation of African Swine Fever Virus in Wintertime
by Tessa Carrau, Alvydas Malakauskas, Marius Masiulis, Paulius Bušauskas, Sigitas Japertas, Sandra Blome, Paul Deutschmann, Virginia Friedrichs, Simona Pileviečienė, Klaas Dietze, Daniel Beltrán-Alcrudo, Márk Hóvári and Gary A. Flory
Pathogens 2023, 12(2), 285; https://doi.org/10.3390/pathogens12020285 - 09 Feb 2023
Viewed by 3284
Abstract
African swine fever (ASF) continues to spread and persist in the Eurasian wild boar population. The infection pressure resulting from infected carcasses in the environment can be a major contributor to disease persistence and spread. For this reason, it is crucial to find [...] Read more.
African swine fever (ASF) continues to spread and persist in the Eurasian wild boar population. The infection pressure resulting from infected carcasses in the environment can be a major contributor to disease persistence and spread. For this reason, it is crucial to find a safe and efficient method of carcass disposal under different circumstances. In the presented study, we investigated open-air composting of carcasses under winter conditions in northeastern Europe, i.e., Lithuania. We can demonstrate that the ASF virus (ASFV) is inactivated in both entire wild boar carcasses and pieces thereof in a time- and temperature-dependent manner. Composting piles reached up to 59.0 °C, and ASFV was shown to be inactivated. However, the ASFV genome was still present until the end of the 112-day sampling period. While further studies are needed to explore potential risk factors (and their mitigation), such as destruction of composting piles by scavengers or harsh weather conditions, composting seems to present a valid method to inactivate the ASFV in wild boar carcasses where rendering or other disposal methods are not feasible. In summary, composting provides a new tool in our toolbox of ASF control in wild boar and can be considered for carcass disposal. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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25 pages, 6649 KiB  
Article
Management of a Focal Introduction of ASF Virus in Wild Boar: The Belgian Experience
by Alain Licoppe, Valérie De Waele, Céline Malengreaux, Julien Paternostre, Amaury Van Goethem, Daniel Desmecht, Marc Herman and Annick Linden
Pathogens 2023, 12(2), 152; https://doi.org/10.3390/pathogens12020152 - 17 Jan 2023
Cited by 7 | Viewed by 2537
Abstract
African swine fever (ASF) is a fatal disease of suids that was detected in wild boar in Belgium in September 2018. The measures implemented to stop the spread and eliminate the African swine fever virus consisted of creating restriction zones, organising efficient search [...] Read more.
African swine fever (ASF) is a fatal disease of suids that was detected in wild boar in Belgium in September 2018. The measures implemented to stop the spread and eliminate the African swine fever virus consisted of creating restriction zones, organising efficient search and removal of carcasses, constructing wire fences, and depopulating wild boar in the area surrounding the infected zone. The ASF management zone included the infected and the white zones and covered 1106 km² from which 7077 wild boar have been removed. A total of 5338 wild boars have been qPCR-tested and 833 have been detected ASF-positive. The search effort amounted to 60,631 h with a main focus on the infected zone (88%). A total of 277 km of fences have been set up. The main cause of mortality in the infected zone was the virus itself, while hunting, trapping, and night shooting were used together to reduce the wild boar density in the surrounding white zones. After continuous dispersion of the virus until March 2019, the epidemic wave stopped, and the last fresh positive case was discovered in August 2019. Hence, Belgium was declared free of the disease in November 2020. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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10 pages, 12035 KiB  
Article
Patterns of ASFV Transmission in Domestic Pigs in Serbia
by Dimitrije Glišić, Vesna Milićević, Ljubiša Veljović, Bojan Milovanović, Branislav Kureljušić, Igor Đorđević, Katarina Anđelković, Jelena Petković and Miroljub Dačić
Pathogens 2023, 12(1), 149; https://doi.org/10.3390/pathogens12010149 - 16 Jan 2023
Cited by 4 | Viewed by 1790
Abstract
The first case of African swine fever in domestic pigs in Serbia was in 2019. The following year, the disease was confirmed in wild boar. Thenceforth, ASF has been continuously reported in both wild and domestic pigs. The outbreaks in domestic pigs could [...] Read more.
The first case of African swine fever in domestic pigs in Serbia was in 2019. The following year, the disease was confirmed in wild boar. Thenceforth, ASF has been continuously reported in both wild and domestic pigs. The outbreaks in domestic pigs could not be linked directly to wild boars, even though wild boars were endemically infected, and reservoirs for ASF. This study aimed to investigate outbreaks and routes of transmission in domestic pigs in a region of central Serbia where no outbreaks in wild boar were reported. Fourteen outbreaks of ASF on backyard farms with low biosecurity were traced back, and no connection to wild boar was found. The epidemic investigation covered 2094 holdings, with 24,368 pigs, out of which 1882 were tested for ASF. In surrounding hunting grounds, field searches were conducted. Dead wild boars were found, and 138 hunted wild boars were negative for ASFV. It was concluded that outbreaks in 2021 were provoked by the illegal trade of live animals and pig products. Even though infective pressure from wild boars is assumed, no positive cases have been found, while the ASFV spreads within the domestic swine population evidenced in four recent outbreaks in 2022. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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18 pages, 2263 KiB  
Article
Artificial Insemination as an Alternative Transmission Route for African Swine Fever Virus
by Virginia Friedrichs, Darwin Reicks, Tobias Hasenfuß, Elisabeth Gerstenkorn, Jeffrey J. Zimmerman, Eric A. Nelson, Tessa Carrau, Paul Deutschmann, Julia Sehl-Ewert, Hanna Roszyk, Martin Beer, Jane Christopher-Hennings and Sandra Blome
Pathogens 2022, 11(12), 1539; https://doi.org/10.3390/pathogens11121539 - 14 Dec 2022
Cited by 4 | Viewed by 6570
Abstract
The rapid spread of the African swine fever virus (ASFV), causing severe disease with often high fatality rates in Eurasian suids, prevails as a threat for pig populations and dependent industries worldwide. Although advancing scientific progress continually enhances our understanding of ASFV pathogenesis, [...] Read more.
The rapid spread of the African swine fever virus (ASFV), causing severe disease with often high fatality rates in Eurasian suids, prevails as a threat for pig populations and dependent industries worldwide. Although advancing scientific progress continually enhances our understanding of ASFV pathogenesis, alternative transmission routes for ASFV have yet to be assessed. Here, we demonstrate that ASFV can efficiently be transferred from infected boars to naïve recipient gilts through artificial insemination (AI). In modern pig production, semen from boar studs often supplies many sow herds. Thus, the infection of a boar stud presents the risk of rapidly and widely distributing ASFV within or between countries. Daily blood and semen collection from four boars after intramuscular inoculation with ASFV strain ‘Estonia 2014’ resulted in the detection of ASFV genomes in the semen as early as 2 dpi, in blood at 1 dpi while semen quality remained largely unaffected. Ultimately, after insemination with extended semen, 7 of 14 gilts were ASFV positive by 7 days post insemination, and all gilts were ASFV positive by 35 days post insemination. Twelve out of 13 pregnant gilts aborted or resorbed at the onset of fever. A proportion of fetuses originating from the remaining gilt showed both abnormalities and replication of ASFV in fetal tissues. Thus, we present evidence for the efficient transmission of ASFV to gilts via AI and also to implanted embryos. These results underline the critical role that boar semen could play in ASFV transmission. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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16 pages, 1774 KiB  
Article
A Novel Tool to Assess the Risk for African Swine Fever in Hunting Environments: The Balkan Experience
by Mario Orrico, Mark Hovari and Daniel Beltrán-Alcrudo
Pathogens 2022, 11(12), 1466; https://doi.org/10.3390/pathogens11121466 - 03 Dec 2022
Viewed by 1843
Abstract
In Europe, African swine fever (ASF) can be sustained within wild boar populations, thus representing a constant source of virus and a huge challenge in the management of the disease. Hunters are the key stakeholders for the prevention, detection and control of ASF [...] Read more.
In Europe, African swine fever (ASF) can be sustained within wild boar populations, thus representing a constant source of virus and a huge challenge in the management of the disease. Hunters are the key stakeholders for the prevention, detection and control of ASF in wild boar. Their behavior and the biosecurity standards applied in infected or at-risk hunting grounds have a huge impact on disease dynamics and management. The Food and Agriculture Organization (FAO) has developed a semi-quantitative survey-based novel tool to assess the risk of ASF in hunting grounds (namely the risks of introduction and spread into and between hunting grounds, and the risk of not detecting the infection) and how such risks could be reduced if mitigation or corrective measures were applied at low, medium and high effort. The weight of risk factors was determined through an expert knowledge elicitation (EKE). The surveys for each hunting ground were filled in by their respective managers. The tool’s outputs allow users to visualize the different ASF risks of hunting grounds, whether as numerical values or color-coded maps, at sub-national, national and regional levels. These outputs can be used to guide policy makers, highlighting gaps or geographical areas to prioritize. The tool was used to assess hunting grounds in Kosovo1 (1 As per United Nations Security Council resolution 1244). Montenegro and Serbia, showing overall a high risk. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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Review

Jump to: Research

27 pages, 479 KiB  
Review
Innovative Research Offers New Hope for Managing African Swine Fever Better in Resource-Limited Smallholder Farming Settings: A Timely Update
by Mary-Louise Penrith, Juanita van Heerden, Dirk U. Pfeiffer, Edvīns Oļševskis, Klaus Depner and Erika Chenais
Pathogens 2023, 12(2), 355; https://doi.org/10.3390/pathogens12020355 - 20 Feb 2023
Cited by 7 | Viewed by 3374
Abstract
African swine fever (ASF) in domestic pigs has, since its discovery in Africa more than a century ago, been associated with subsistence pig keeping with low levels of biosecurity. Likewise, smallholder and backyard pig farming in resource-limited settings have been notably affected during [...] Read more.
African swine fever (ASF) in domestic pigs has, since its discovery in Africa more than a century ago, been associated with subsistence pig keeping with low levels of biosecurity. Likewise, smallholder and backyard pig farming in resource-limited settings have been notably affected during the ongoing epidemic in Eastern Europe, Asia, the Pacific, and Caribbean regions. Many challenges to managing ASF in such settings have been identified in the ongoing as well as previous epidemics. Consistent implementation of biosecurity at all nodes in the value chain remains most important for controlling and preventing ASF. Recent research from Asia, Africa, and Europe has provided science-based information that can be of value in overcoming some of the hurdles faced for implementing biosecurity in resource-limited contexts. In this narrative review we examine a selection of these studies elucidating innovative solutions such as shorter boiling times for inactivating ASF virus in swill, participatory planning of interventions for risk mitigation for ASF, better understanding of smallholder pig-keeper perceptions and constraints, modified culling, and safe alternatives for disposal of carcasses of pigs that have died of ASF. The aim of the review is to increase acceptance and implementation of science-based approaches that increase the feasibility of managing, and the possibility to prevent, ASF in resource-limited settings. This could contribute to protecting hundreds of thousands of livelihoods that depend upon pigs and enable small-scale pig production to reach its full potential for poverty alleviation and food security. Full article
(This article belongs to the Special Issue An Update on African Swine Fever)
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