African Swine Fever Research Articles

The I226R protein of African swine fever virus inhibits the cGAS-STING-mediated innate immune response

This study aimed to explore the mechanism of how African swine fever virus (ASFV) I226R protein inhibits the cGAS-STING signaling pathway. We observed that I226R protein (pI226R) significantly inhibited the cGAS-STING-mediated type Ⅰ interferons and the interferon-stimulated genes production by dual-luciferase reporter assay system and real-time quantitative PCR. The results of co-immunoprecipitation assay and confocal microscopy showed that pI226R interacted with cGAS. Furthermore, pI226R promoted cGAS degradation through autophagy-lysosome pathway. Moreover, we found that pI226R decreased the binding of cGAS to E3 ligase tripartite motif protein 56 (TRIM56), resulting in the weakened monoubiquitination of cGAS, thus inhibiting the activation of cGAS and cGAS-STING signaling. In conclusion, ASFV pI226R suppresses the antiviral innate immune response by antagonizing cGAS, which contributes to an in-depth understanding of the immune escape mechanism of ASFV and provides a theoretical basis for the development of vaccines.

Priority directions for improving the marketing strategy of agricultural enterprises of Ukraine

The article presents the results of the analysis of the state of the agrarian sector of the economy of Ukraine, which is suffering as a result of a prolonged crisis situation. A large part of farms have suffered in recent years from African swine fever, the COVID-19 pandemic, and hostilities. There was a decrease in the export of agricultural products and food products, in particular, grain, oilseeds, sunflower oil, and sugar. In 2022, losses in the industry, according to the calculations of the Ministry of Agrarian Policy, exceeded 40 billion dollars. USA. At the same time, the revival of agricultural enterprises, the restoration of production and cooperative relations began. However, many farms, especially in regions close to hostilities, need to review their development strategies, business plans, conduct an analysis of the market and the needs of the population, their own production capacities, etc. Having correctly made an assessment, they can coordinate or restructure the work of the enterprise in such a way that it not only remains «afloat», but also makes a profit. The article identifies trends in the development of small and medium-sized agribusiness and offers recommendations for marketing activities in crisis conditions. In particular, it is proposed to establish cooperation not only with existing trade networks, but also to attract private entrepreneurs, develop own trade, direct contacts with buyers, reduce the cost of products, develop and implement new logistics routes, expand the range of products, etc.

Retrospective Multi-Locus Sequence Analysis of African Swine Fever Viruses by "PACT" Confirms Co-Circulation of Multiple Outbreak Strains in Uganda.

African swine fever (ASF) is a haemorrhagic fever of swine that severely constrains pig production, globally. In Uganda, at least 388 outbreaks of ASF were documented from 2001 to 2012. We undertook a retrospective serological and molecular survey of ASF virus (ASFV) using banked samples collected from seven districts (Pallisa, Lira, Abim, Nebbi, Kabarole, Kibaale, and Mukono) of Uganda. Six assays (ELISA for antibody detection, diagnostic p72 gene PCR and genomic amplification, and sequencing of four gene regions (p72 [P], p54 [A], CVR of the 9RL-ORF [C], and TK [T]), hereinafter referred to as P-A-C-T (PACT)) were evaluated. Antibodies to ASFV were detected in the Abim district (6/25; 24.0%), and the remainder of the serum samples were negative (187/193; 96.9%). For the tissue samples, ASFV detection by assay was 8.47% for P, 6.78% for A, 8.47% for C, and 16.95% for T. The diagnostic PCR (p72 gene) detected seven positive animals from four districts, whereas the TK assay detected ten positives from all seven districts. In addition to the superior detection capability of TK, two virus variants were discernible, whereas CVR recovered three variants, and p72 and p54 sequencing each identified a single variant belonging to genotype IX. Our results indicate that dependence on serology alone underestimates ASF positivity in any infected region, that multi-locus sequence analysis provides better estimates of outbreak strain diversity, and that the TK assay is superior to the WOAH-prescribed conventional p72 diagnostic PCR, and warrants further investigation.

Sejarah Perdagangan Babi dari Pulau Bulan Batam ke Singapura, 1987-2023

This research delves into the pig trade history from Pulau Bulan, Batam, to Singapore spanning 1987 to 2023. In response to the 1984 policy eliminating domestic livestock farming, Singapore became reliant on imported meat. Employing a historical research method and drawing on literature reviews, the study identifies PT Indo Tirta Suaka's Pulau Bulan pig farm as Southeast Asia's largest and Singapore's primary live pig importer, initiating exports in 1987. Disruptions occurred, such as Singapore's cessation of pig supplies from Malaysia during Foot and Mouth Disease (FMD) outbreaks in Sarawak (1999-2017) and the Covid-19 pandemic. However, a significant setback unfolded with the detection of African Swine Fever (ASF) on April 19, 2023. Subsequent tests confirmed ASF in Pulau Bulan pig samples, prompting Singapore to officially halt pig supplies. This resulted in a substantial monthly and yearly loss of approximately IDR 3.5 billion and IDR 1.1 trillion, respectively, in pig exports from Pulau Bulan to Singapore.

The Long-Jumping of African Swine Fever: First Genotype II Notified in Sardinia, Italy.

African swine fever (ASF) is a devastating infectious disease of domestic pigs and wild boar that is spreading quickly around the world and causing huge economic losses. Although the development of effective vaccines is currently being attempted by several labs, the absence of globally recognized licensed vaccines makes disease prevention and early detection even more crucial. ASF has spread across many countries in Europe and about two years ago affected the Italian susceptible population. In Italy, the first case of ASF genotype II in wild boar dates back to January 2022, while the first outbreak in a domestic pig farm was notified in August 2023. Currently, four clusters of infection are still ongoing in northern (Piedmont-Liguria and Lombardy), central (Lazio), and southern Italy (Calabria and Campania). In early September 2023, the first case of ASFV genotype II was detected in a domestic pig farm in Sardinia, historically affected by genotype I and in the final stage of eradication. Genomic characterization of p72, p54, and I73R/I329L genome regions revealed 100% similarity to those obtained from isolates that have been circulating in mainland Italy since January 2022 and also with international strains. The outbreak was detected and confirmed due to the passive surveillance plan on domestic pig farms put in place to provide evidence on genotype I's absence. Epidemiological investigations suggest 24 August as the most probable time of ASFV genotype II's arrival in Sardinia, likely due to human activities.

Tackling African swine fever in India

Abstract Globally, African swine fever (ASF) is the most feared swine viral disease, associated with a mortality rate of up to 100%. More than half of the world’s swine population is located in Asia. ASF outbreaks in Asia have a significant impact on the global pig industry. Pig industry’s economic losses have been huge because of ASF outbreaks. Swine husbandry in India is in a flourishing phase to meet food security demands, but the losses associated with ASF greatly hamper its expansion. ASF in India can be controlled and eradicated through strict biosecurity measures and vaccination. Development of penside point-of-care (POC) rapid diagnostics and effective indigenous vaccines are prerequisites to tackle ASF in India. Sensitization of veterinary professionals, researchers, and pig farmers about disease pathogenesis, transmission, and impact are crucial part of ASF control. This review presents the status of ASF in India in comparison to other parts of the world, and current approaches in India to deal with ASF. Further roadmap to combat this calamitous swine infection in India.

Wild Boar (Sus scrofa L.) as the Biomonitor of Cadmium and Lead Pollution in the Republic of North Macedonia

Until the outbreak of African swine fever in almost the entire Europe and consequently in the Republic of North Macedonia (2022), the population of wild boars was in increase. The biological characteristics of this species make it suitable to be used as a bioindicator for environmental pollution. The concentrations of cadmium and lead (Cd and Pb) were measured using atomic absorption spectrophotometry in the liver of free ranging wild boars. Samples were taken from 608 animals, harvested in a period of 7 years (2016-2022), in 11 hunting locations that cover the whole territory of the Republic of North Macedonia. The mean value of Pb in the liver in all hunting areas was 0.225 mg·kg-1 wet weight with range of 0.154-0.722 mg·kg-1, while mean Cd was 0.366 mg·kg-1 and ranged from 0.177 to 0.464 mg·kg-1. A statistically significant difference in Cd was found between the hunting locations, while Pb differed between hunting years. The mean Cd concentrations were significantly higher in Pelagonisko, Krivorečansko and Ohridsko-Prespansko hunting areas than in those from Pološko hunting area, while the mean Pb values in 2019 and 2020 were significantly higher than the mean value determined in 2021. For Cd, 18.2% of the total number of samples exceeds the maximum allowed limit provided in the legislation, while for Pb it was 6.7%. The maximum mean value for Pb (0.336 mg·kg-1) was measured in 2020 and for Cd (0.449 mg·kg-1) in 2016. The mean values for Pb and Cd obtained in this study were in line with data reported for wild boar from other European countries.

CO2 bubbling pretreatment to remove the inhibition of lime disinfection wastewater in a swine manure anaerobic digestion system

Under the African swine fever epidemic, the extensive use of lime disinfectants has seriously inhibited anaerobic digestion (AD). In this study, the subject was swine manure containing lime disinfectant wastewater. The research set up a carbon dioxide (CO2) bubbling pretreatment device before it entered AD to explore the effect of breaking the inhibition of lime disinfectant. The results showed that the initial pulmonary hypertension (pH) of 11.0 and CO2 bubbling time of 8 h had the best effect, which could reduce calcium ion (Ca2+) by 73.0%, and the biogas production of the batch AD test increased by 28 times. In the continuous AD test, the Ca2+ of CK increased to 7.67 g/L, while the S1 pretreated by CO2 bubbling stabilized at 2.6 g/L, the biogas production in S1 was 112.4% higher than in CK. CO2 bubbling pretreatment reduces the concentration of Ca2+ in swine by utilizing the combination of exogenous CO2 and Ca2+, breaking the inhibitory effect on AD, and thereby improving the performance of the AD system. The test used CO2 in biogas to break the inhibition of lime disinfectants on AD, which was a convenient and feasible pretreatment process.

From pigs to wild boars, the rise of African swine fever in India.

African swine fever (ASF) is an infectious transboundary disease of domestic pigs and wild boars. In India, introduction of ASF in early 2020 from outbreaks in domestic pigs reported from two north-eastern states and its further spread to several Indian states inflicted severe losses in pig and pork production. ASF has also been reported in wild boars (Sus scrofa) indicating a local transmission from domestic pigs with a high likelihood that it might attain an endemic status and threaten wildlife conservation by endangering the pygmy hogs (Porcula salvania), the world's smallest wild pig native to this region. To ensure future food security and prevent the implications of ASF in India, biosecurity and border measures, disease control strategies and production systems must be improved and modernized.

The Spatiotemporal Epidemiology of African Swine Fever in the Mekong Delta and the Review of Vaccine Development in Vietnam

The Spatiotemporal Epidemiology of African Swine Fever in the Mekong Delta and the Review of Vaccine Development in Vietnam

African Swine Fever and Its Control Measures in Wild Boar: A "De Iure Condito" Analysis in the European Union.

Recently, the African swine fever (ASF) epizootic has been reported in domestic pigs and wild boars in several European Union Member States (EU MS) and epidemiological evidence has accumulated which indicates that wild boar play a key role in maintaining and spreading the disease. Thanks to the experience gained when managing ASF outbreaks in Sardinia (Italy) and Eastern Europe, Directive 2002/60 CE was issued. This directive represented an important step forward in controlling the disease, particularly the risk of spreading the virus to wild animals. Since 2021, according to Regulation (EU) 2016/429, which is also called "Animal Health Law-AHL", when the MS competent authority suspects or confirms ASF (a cat. A listed disease) in wild animals, it is mandatory to conduct surveillance in the wild boar population and implement the necessary control measures. Within AHL, Regulations (EU) 2020/687 and 2023/594 established special ASF control measures in kept and wild porcine animals, and their products and by-products, focusing on and underlying old and new responsibilities that vets (both public and private ones) have to accomplish under the new regulations. The new change in the legal framework deals with specific measures to be applied in the wild and represents a great challenge for MS veterinary services. Some of these measures have been well established in the last two decades, particularly those related to application in the farming system, while other measures are still new to veterinary health management and require a holistic approach in terms of intensity, considering all geographical, ecological, productive, cultural and social features of the involved EU MS. In this contribution, the authors intend to focus on specific measures which have been issued in order to limit or stop the spread of ASF in a wild, "boundless" ecosystem. These measures expand the field of competence of the official veterinary service to wild areas in addition to farm activity.

2023 International African Swine Fever Workshop: Critical Issues That Need to Be Addressed for ASF Control.

The 2023 International African Swine Fever Workshop (IASFW) took place in Beijing, China, on 18-20 September 2023. It was jointly organized by the U.S.-China Center for Animal Health (USCCAH) at Kansas State University (KSU) and the Chinese Veterinary Drug Association (CVDA) and sponsored by the United States Department of Agriculture Foreign Agricultural Service (USDA-FAS), Harbin Veterinary Research Institute, and Zoetis Inc. The objective of this workshop was to provide a platform for ASF researchers around the world to unite and share their knowledge and expertise on ASF control and prevention. A total of 24 outstanding ASF research scientists and experts from 10 countries attended this meeting. The workshop included presentations on current ASF research, opportunities for scientific collaboration, and discussions of lessons and experiences learned from China/Asia, Africa, and Europe. This article summarizes the meeting highlights and presents some critical issues that need to be addressed for ASF control and prevention in the future.

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.

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.

The first outbreak of African swine fever in Sweden: a survey of pig farmers' perceptions of information received, risks, biosecurity measures and future prospects

BackgroundAfrican swine fever (ASF), a viral hemorrhagic disease in domestic pigs and wild boar with up to 100% case fatality, was confirmed in Swedish wild boar in September 2023. The responsible authorities launched a control programme to eradicate the infection. The aim of the current study was to understand (i) how Swedish pig farmers have perceived the information issued by authorities and other stakeholders since the discovery of ASF in wild boar, (ii) which risks they see for introducing the infection to their farm, (iii) what biosecurity measures they have taken on their farms, and (iv) their outlook on the future. Such information is important for evaluating the effectiveness of the early stages of ASF control in Sweden. A questionnaire was designed and distributed to members of the Swedish pig producers’ organisation.ResultsA total of 155 farmers responded to the survey (response rate 36%). Almost all respondents had received general information about ASF (91%, n = 138), and 72% (n = 109) had received information about how they can protect their farm from ASF introduction. A majority (87%, n = 118) thought the information was easy to understand, 90% (n = 137) that is was relevant, and 77% (n = 117) that they currently did not lack any information. If given the resources necessary, 58% (n = 84) of the farmers would like to take additional measures such as fencing, and heavily reduce or eradicate the wild boar population. Wild boars were considered the greatest risk for introduction of ASF into their herd (39%, n = 57), followed by people (30%, n = 44), and transports (16%, n = 23). Many farmers (66%, n = 88) had a positive outlook on the future, and 89% (n = 127) have not changed their plans for the future since the ASF outbreak.ConclusionsThe responding farmers were in general satisfied with the information received in the beginning of the ASF outbreak. The majority have a positive outlook on the future and the outbreak has not caused them to change their plans. Actions that were highlighted as important to safeguard Sweden's pig production included measures to control the wild boar population.

The Production of Recombinant African Swine Fever Virus Lv17/WB/Rie1 Strains and Their In Vitro and In Vivo Characterizations.

Lv17/WB/Rie1-Δ24 was produced via illegitimate recombination mediated by low-dilution serial passage in the Cos7 cell line and isolated on PAM cell culture. The virus contains a huge ~26.4 Kb deletion in the left end of its genome. Lv17/WB/Rie1-ΔCD-ΔGL was generated via homologous recombination, crossing two ASFV strains (Lv17/WB/Rie1-ΔCD and Lv17/WB/Rie1-ΔGL containing eGFP and mCherry markers) during PAM co-infection. The presence of unique parental markers in the Lv17/WB/Rie1-ΔCD-ΔGL genome indicates at least two recombination events during the crossing, suggesting that homologous recombination is a relatively frequent event in the ASFV genome during replication in PAM. Pigs infected with Lv17/WB/Rie1-Δ24 and Lv17/WB/Rie1/ΔCD-ΔGL strains have shown mild clinical signs despite that ASFV could not be detected in their sera until a challenge infection with the Armenia/07 ASFV strain. The two viruses were not able to induce protective immunity in pigs against a virulent Armenia/07 challenge.

Differential infection behavior of African swine fever virus (ASFV) genotype I and II in the upper respiratory tract

African swine fever virus (ASFV) is a substantial threat to pig populations worldwide, contributing to economic disruption and food security challenges. Its spread is attributed to the oronasal transmission route, particularly in animals with acute ASF. Our study addresses the understudied role of nasal mucosa in ASFV infection, using a nasal explant model. The explants remained viable and revealed a discernible ASFV infection in nasal septum and turbinates post-inoculation. Interestingly, more infected cells were found in the turbinates despite its thinner structure. Further analyses showed (i) a higher replication of genotype II strain BEL18 than genotype I strain E70 in the epithelial cell layer, (ii) a preference of ASFV infection for the lamina propria and a tropism of ASFV for various susceptible cell types in different areas in the nasal mucosa, including epithelial cells, macrophages, and endothelial cells. Using porcine respiratory epithelial cells (PoRECs), isolated from nasal tissue, we found a difference in infection mechanism between the two genotypes, with genotype I favoring the basolateral surface and genotype II preferring the apical surface. Moreover, disruption of intercellular junctions enhanced infection for genotype I. This study demonstrated that ASFV may use the respiratory mucosa for entry using different cell types for replication with a genotype difference in their infection of respiratory epithelial cells.

Targeted mutagenesis of the β-strand DNA binding region of African swine fever virus histone-like protein (pA104R) impairs DNA-binding activity and antibody recognition

African Swine Fever (ASF) is a highly contagious disease caused by a double-stranded DNA virus (ASFV). Despite significant advances made over the last decade, issues such as residual virulence and absence of differentiating infected from vaccinated animals (DIVA) capacity remain an obstacle in the development of live attenuated vaccines (LAVs) against ASFV. It is, therefore, necessary to identify novel strategies to improve vaccine safety, by rational mutagenesis of virulence associated genes and generation of DIVA markers. ASFV encodes a HU (histone-like protein from E. coli strain U93) homolog protein, pA104R, which is involved in viral genome assembly and host immune recognition. A phylogenetic analysis revealed that pA104R is highly conserved among ASFV isolates, suggesting that it can be a good target for vaccine design. Thus, we selectively mutated the β-strand DNA binding region (BDR) of pA104R to attenuate its enzymatic activity, and identified and mutated several B-cell epitopes present in pA104R to generate a negative marker. Residues K64, K66, and R69 in the BDR were identified as relevant for pA104R activity, with double mutation of the first two showing additive attenuation. pA104R-reactive IgM and IgG epitopes were also identified in the bottom of the BDR, with selective mutagenesis drastically reducing antibody recognition and, when combined with mutations in the arm of the BDR, leading to a further reduction of DNA-binding activity. Interestingly, the immunodominant pA104R-reactive IgG epitope was mainly recognized by IgG1 suggesting that pA104R induces a dominant Th2 response. In sum, the rational mutagenesis can reduce pA104R-DNA binding activity and immune reactivity, providing a rationale for the development of an ASFV pA104R-based DIVA vaccine.

Sequencing p72 gene of field strain of African swine fever virus (ASFV) in Vietnam and generation of enhanced immunogenic fusion protein G-p72 potentially expressed as a recombinant antigen in ASFV subunit vaccine

Protein p72 is the major surface protein of African swine fever virus (ASFV), which is immunogenic and can prime the host to elicit a protective immune response, while G protein is the surface glycoprotein of vesicular stomatitis virus (VSV), which is well-known to be a strong antigen to stimulate an effective humoral immunity. The aim of this study was to sequence full length p72 gene of a field strain of ASFV causing typical ASF in Dong Nai province in 2020 and fuse this p72 gene with VSV G gene to generate a recombinant fusion gene G-p72 that could simultaneously express both proteins and stimulate a better host immune response than p72 expression alone. The sequence of the gene showed 99.59% nucleotide sequence similarity to an ASFV isolate from China. The PCR was employed to produce the recombinant G-p72 gene, which was cloned into plasmid pET28a, followed by transformation into E. coli BL21 (DE3) for protein expression. The G-p72 expression was induced at 37°C and 28°C for 6 and 16 h, respectively. The expression showed that G-p72 was observed at 28°C for 16 h. In summary, the full length p72 gene of a field strain of ASFV was successfully sequenced and expressed as the recombinant G-p72 protein in E. coli BL21 (DE3). The expression level of the G-p72 fusion should be optimized and the immunogenicity of the recombinant protein should be examined in futher studies.

Detection of African swine fever virus and wild boar eDNA in soil and turbid water samples: towards environmental surveillance

Since 2007, an ongoing African swine fever (ASF) pandemic has significantly impacted Eurasia. Extensive field evidence and modeling confirm the central role of wild boar in ASF epidemiology. To effectively control and eradicate the infection, rapid detection of the ASF virus (ASFV) is crucial for prompt intervention in areas of recent viral introduction or ongoing outbreaks. Environmental DNA (eDNA) is a cost-effective and non-invasive technique that has shown promising results in monitoring animal species and their pathogens and has the potential to be used for wildlife disease surveillance. In this study, we designed and evaluated an eDNA sampling method for highly turbid water and soil samples to detect ASFV and wild boar (Sus scrofa) DNA as a control using qPCR while ensuring biosafety measures and evaluating ASF epidemiology. To validate our method, we obtained samples from La Mandria Regional Park (LMRP) in northwestern Italy, an area free of ASFV, and spiked them in a laboratory setting with an ASFV’s synthetic DNA template. Our findings highlight the potential of eDNA monitoring as a reliable, rapid, and safe method for early detection of ASFV from soil and turbid water samples.

The p30 protein of the African swine fever virus behaves as an RNase

The African Swine Fever Virus (ASFV) is responsible for causing African Swine Fever (ASF), a severe contagious disease characterized by hemorrhagic symptoms. The p30 protein of ASFV is the most abundantly expressed viral protein. It is reported to be antigenic and has recognized phosphorylation, glycosylation, and membrane attachment sites, which also shows that the C-terminal region of p30 is more active than the N-terminal region. The present study reports the unique RNase activity of recombinant p30. The RNase activity of p30 was stable at an optimum temperature of 37 °C, and the maximum activity was recorded at pH 7–9 in the presence of monovalent salts. The mutant of p30 (p30m), where cysteine was mutated to alanine at position 109, showed a loss of RNase activity. Our understanding of ASFV biology is significantly less; until now, we have little knowledge about the functions of its proteins. The results of the present study will assist in exploring the biology of ASFV and the role of its protein in counteracting the host immune response.