Search Results (427)

African swine fever (ASF) continues to spread, threatening the global swine industry and endangered swine species. Sri Lanka is a tropical island situated south of India in the Indian Ocean. Here, we report the first detection of ASF in Sri Lanka. In September 2024, increased pig mortality was reported across the country, with initial confirmation of porcine reproductive and respiratory syndrome (PRRS). Despite vaccination for PRRS, the mortalities continued to increase and therefore, tissue samples collected from dead pigs were subjected to ASF real-time PCR. ASFV genomic material was detected in most of the samples. The real-time PCR-positive samples were then subjected to genotyping by partial genome sequencing. All p72 and p54 sequences were found to be aligned with ASFV genotype II viruses, and CD2v sequences were found to be aligned with ASFV serogroup 8 viruses. The real-time PCR-positive samples were inoculated onto primary porcine leukocytes for virus isolation, and a selected number of tissues collected from dead pigs were subjected to histopathology. Histopathological studies revealed widespread loss of lymphocytes together with inflammation and extensive staining of ASFV antigens in tissue samples. Hemadsorption (HAD)-positive isolates were obtained from seven clinical samples, and three of them were subjected to whole-genome sequencing. Phylogeographic analysis of the whole-genome sequences showed that the virus is closely related to ASFV strains circulating in China and Hong Kong. Full article

African Swine Fever is a lethal hemorrhagic disease caused by a DNA virus that affects domestic and wild pigs, causing serious economic losses in the swine industry. African Swine Fever virus (ASFV) is maintained in a sylvatic cycle that includes wildlife and Ornithodoros tick species. A huge investigation about ASFV structure and its infection process in pigs has been carried out in recent years, and although these studies have increased our knowledge about its pathogenesis, there are still many unclear aspects about which immune responses protect swine hosts against the disease caused by this virus. The mechanisms of ASFV infection in ticks are even less well understood. This infection is long term and persistent, with relatively high levels of virus replication in different tick tissues. According to specific infected tissues, the Ornithodoros tick species that are ASFV-competent vectors show transstadial, transovarial and/or venereal transmissions. This review is focused on the main process taking place at the virus–vector interface, summarizing the latest findings about the molecular and cellular aspects of ASFV infection in ticks, which could constitute the basis for developing novel strategies to interrupt the arthropod transmission cycle. Full article

Background/Objectives: Inadequate characterization of protective antigens poses a significant challenge to the development of vaccines for African swine fever (ASF), particularly for antigen-dependent formulations such as subunit, mRNA, and recombinant viral vector vaccines. To address this, we aimed to screen African swine fever virus (ASFV) antigens and enhance their immunogenicity using a nanoparticle delivery platform. Methods: Here, six ASFV antigens (p30, p54, pE120R, pH124R, pE184L, and CD2v) were purified and used to immunize pigs individually. The effects of antibodies induced by these six antigens on ASFV replication or hemadsorption was evaluated in primary porcine alveolar macrophages (PAMs). These six antigens were, respectively, conjugated to ferritin via SpyTag/SpyCatcher to prepare six ferritin nanoparticles. A cocktail of the six mixed antigens or a cocktail of the six mixed nanoparticles was used to immunize pigs separately, and the differences in induced humoral and cellular immune responses were compared. Results: Antibodies generated against p30, p54, pE120R, pH124R, and pE184L in immunized pigs significantly inhibited ASFV replication in PAMs, while anti-CD2v antibodies specifically obstructed the hemadsorption of ASFV. Notably, immunization with a cocktail of these antigen-conjugated nanoparticles elicited a stronger virus-inhibitory antibody response compared to immunization with a cocktail of antigen monomers. Furthermore, nanoparticle immunization induced robust cellular immunity, evidenced by elevated serum IFN-γ, increased numbers of ASFV-specific IFN-γ-secreting cells, and an expanded CD8⁺ T cell population. Conclusions: Our study identifies a set of promising ASFV antigen candidates and demonstrates that ferritin nanoparticle delivery synergistically enhances both humoral and cellular immune responses against ASFV, providing a rational strategy for multi-antigen ASF vaccine design. Full article

This study integrates data on the prevalence, infection dynamics and risks associated with African swine fever virus (ASFV) outbreaks in Croatian wild boar during 2023–2024. Although the overall ASFV DNA prevalence in Croatia was 0.24%, the highest prevalence (2.29% in 2023 and 4.69% in 2024) was recorded in Vukovar-Srijem County. Genetic typing identified ASFV genotype II, subgroup 19, consistent with strains isolated from domestic pigs in Croatia and circulating in neighboring countries. Anti-ASFV specific antibodies were detected in 10.34% of wild boar tested in counties with previously reported DNA findings. In Vukovar-Srijem County, 4.60% of wild boar were positive for both, ASFV DNA and antibodies, suggesting ongoing virus infection, whereas the proportion of boar positive only for antibodies was 5.75%, indicating survival of acute infection. Statistical analysis revealed an increase in ASFV DNA detection from 2023 to 2024 (p = 0.043), with a higher prevalence in carcasses than in hunted animals (p = 0.001), highlighting the need for passive monitoring. While gender showed no statistical significance, a higher infection rate was observed in older animals (p = 0.001). The identified course of infection involved spillover events between domestic pigs and wild boar, with a significant anthropogenic influence. Full article

African Swine Fever (ASF) control is severely hampered by the reliance on slow, laboratory-bound diagnostics. While rapid, field-deployable lateral flow assays (LFAs) are urgently needed, the comparative performance of key single-antigen targets remains poorly characterized. This study aimed to develop and systematically evaluate the diagnostic performance of three in-house single-antigen LFAs targeting ASF virus P30, P54, and P72, using swine field samples from Thailand, including a panel of 143 quantitative polymerase chain reaction-negative swine serum samples. The performance of each LFA was compared against a commercial multi-antigen (P32/P62/P72) indirect ELISA, which served as the reference standard, classifying 64 samples as positive and 79 as negative. The P72-based LFA demonstrated perfect diagnostic performance (100% sensitivity, 100% specificity) and perfect agreement (κ = 1.0) with the enzyme-linked immunosorbent assay (ELISA). Similarly, the P30 LFA demonstrated high performance (100% sensitivity, 98.7% specificity) with ‘Almost Perfect’ agreement (κ = 0.9859). In contrast, the P54 LFA was unsuitable, achieving 100% sensitivity but unacceptably low specificity (88.6%) due to a high rate of false positives. Overall, the single-antigen P72 and P30 LFAs demonstrated excellent concordance with the multi-antigen ELISA, supporting their reliable for detecting antibodies against ASFV. Although these assays do not replace molecular methods for acute infection detection, they represent valuable complementary tools for serosurveillance. Full article

Background: Individual differences in immune responses to African swine fever virus (ASFV), whether induced by vaccination or natural infection, may be linked to genetic variation in the genes involved in antigen presentation. Methods: A total of nine pigs from the 112-population were selected for RNA-seq analysis. To pinpoint key transcription factors (TFs) regulating gene expression in the lymph nodes, weighted Kendall’s Tau rank correlation analysis was performed to link the TF binding potential with the extent of differential expression of target genes. Results: CD8⁺ T cells expressing a specific epitope of the ASFV p72 protein (ACD8⁺) accounted for 41% of the total CD8⁺ T cells in peripheral blood. A total of 2062 transcripts were identified as differentially expressed across the nine pigs (q-value < 1 × 10⁻⁸). Differential expression levels of the target genes for MECP2, ETS1, ZBTB33, ELK4, and E2F4 were significantly correlated with their TF binding potential (p < 0.05). Six SNPs were identified in the promoter region of ELK4. Analysis of the 112-pig population revealed that SNPs at S.-404A>G and S.-668C>T loci were significantly associated with ACD8⁺ levels (q-value < 0.01). Individuals with the AA genotype at S.-404A>G had significantly higher ACD8⁺ counts compared to those with AG and GG genotypes (q-value < 0.05). At the S.-668C>T locus, ACD8⁺ levels were highest in the CC genotype, followed by CT and TT genotypes, with CC showing notably higher ACD8⁺ counts (q-value < 0.05). Notably, the S.-404A>G site overlaps with potential binding sites for TFs FOXA2, GATAs, and TRPS1, while the S.-668C>T site lies within the binding regions for NR1H3, RARA, VDR, and NR1I3. Conclusion: These mutations may disrupt TFs binding to the ELK4 promoter, potentially reducing ELK4 expression and impairing antigen processing and presentation. Full article

African swine fever virus (ASFV) causes a highly fatal disease in domestic pigs, resulting in substantial economic losses to the global swine industry. Vaccine development continues to be hindered by limited characterization of viral proteins and their functional redundancies. In this study, we employ combined experimental and computational approaches to characterize the ASFV I73R protein (pI73R), which contains a Z-DNA binding domain and plays a critical role in ASFV virulence and pathogenesis. We demonstrate that pI73R shares significant structural similarity with transcription factors of the forkhead box (FOX) protein family. Overexpression of pI73R results in downregulation of Crooked neck-like protein 1 (CRNKL1), a core spliceosome component, suggesting a potential mechanism by which pI73R modulates host protein synthesis. Using high-resolution mass spectrometry, we map the pI73R interactome and identify the host protein Guanine nucleotide-binding protein subunit beta-1 (GNB1) as a novel direct interactor of pI73R which may facilitate its nuclear transport. Furthermore, we show that pI73R exhibits consistent oligomerization and expression across different ASFV genotypes, highlighting its functional importance. Taken together, these results provide new insights into pI73R function, ASFV–host dynamics, and offer promising directions for antiviral strategy development. Full article

African swine fever virus (ASFV) is the cause of a severe hemorrhagic disease in domestic pigs and wild boar. Currently, a highly virulent genotype II ASFV is causing massive pig mortality worldwide. In its acute form, the disease is characterized by high fever, a range of non-specific clinical signs and cell death. In this study, we demonstrate a greatly elevated level (>1000-fold) of cell-free DNA (cfDNA), more specifically, fragmented host genomic DNA (gDNA), in serum from both wild boar and domestic pigs infected with a highly virulent genotype II ASFV. Increases were also observed, to a lesser extent, in the serum levels of mitochondrial DNA (between 4- to >500-fold). For comparison, release of the cytoplasmic enzyme, lactate dehydrogenase, which is a commonly used marker for cellular damage, was also found to be elevated in some animals, but with less consistency. These results indicate that gDNA in serum (i.e., cfDNA) can be a useful marker for cell death during infection with highly virulent variants of the virus, and could be a promising biomarker to elucidate the pathogenesis of ASFV infection in both domestic pigs and wild boar in future studies. Full article

ASFV is responsible for high mortality in domestic pigs and has caused substantial economic impact on the global swine industry due to herd losses, trade restrictions, and disease control measures. We analyzed publicly available spleen RNA-seq data from ASFV-infected pigs (n = 13 total samples), including 7 pre-infection (0 dpi), 4 samples at 2 days post-infection (2 dpi), and 2 samples at 5 dpi (5 dpi). Weighted gene co-expression network analysis (WGCNA) identified 19 modules; module–trait correlations revealed six modules associated with infection time. A co-expression module enriched for innate immune and antiviral response genes was strongly upregulated at 2 dpi, whereas a module enriched for ribosomal, translation, and metabolic process genes was broadly downregulated at 5 dpi. Protein–protein interaction analysis highlighted hub genes, including EPRS1 and USP7 within core cellular/translation programs and CMPK2 and ZBP1 within innate-immune signaling. Collectively, our results provide a network-level view of dynamic host responses and indicate coordinated shifts in immune and metabolic programs over time. These results identify CMPK2, ZBP1, EPRS1, and USP7 as hypothesis-generating hub gene candidates, warranting further validation to establish mechanistic roles and assess potential translational relevance. Full article

African swine fever virus (ASFV) poses a significant threat to the global pig industry due to high mortality rates and complex genetic variation. Live attenuated vaccines (LAVs) provide protection against ASFV. Previously, MGF505-2R was identified as a potent inhibitor of innate immunity in vitro. This study evaluates the pathogenicity of a recombinant Eurasian genotype II strain with the MGF505-2R gene deleted (ASFV-ΔMGF505-2R) in piglets. Twelve five-week-old crossbred piglets were divided into two groups, with one group of eight piglets inoculated with ASFV-ΔMGF505-2R (n = 8) and the other group of four piglets inoculated with the same dose of parental ASFV CN/GS 2018 (n = 4). Clinical symptoms, viral loads, and immune responses were monitored over 30 days. ASFV-ΔMGF505-2R-inoculated piglets exhibited transient fever and low viremia only in the beginning of the challenge, while the control group developed high levels of viremia and hyperthermia at day 2 and 8 post-challenge, respectively. Meanwhile, the control group demonstrated more severe post-mortem signs and immuno-histochemistry injury when compared to the ΔMGF505-2R group. ELISA analysis displayed higher levels of IFN-β and IL-1β in the ΔMGF505-2R group, further solidating the immunosuppressive role of MGF505-2R. All ASFV-ΔMGF505-2R-inoculated piglets developed high titers of ASFV-specific P30 antibodies at 10 days post-challenge. These findings rationalized the potential of ASFV-ΔMGF505-2R as a live attenuated candidate for ASF infection. Full article

African swine fever virus (ASFV) is a highly contagious pathogen causing African swine fever in wild boars, warthogs and domestic pigs. The disease leads tosubstantial economic losses to the global pork industry and poses a grave threat to biodiversity. The early-encoded structural protein p22, owing to its immunodominant characteristics and high conservation across most genotypes, represents a promising diagnostic target and subunit vaccine candidate. In this study, the soluble extracellular domain of p22 protein (aa 30–177) was successfully expressed and purified, yielding 1.220 g/L. Eleven strains of monoclonal antibodies against p22 were generated, with four selected for B-cell epitope screening. Bioinformatic prediction-guided design was employed to generate overlapping truncations and peptides for epitope mapping. Based on those strategies, three novel linear B-cell epitopes were identified to be ³⁰KKQQPPKK³⁷, ¹³⁰WGTDDCTG¹³⁷ and ¹⁵⁰YVYNNPHH¹⁵⁷ by monoclonal antibodies. Sequence alignment across ASFV isolates revealed 100% evolutionary conservation in genotypes I/II, with minor variation in genotypes IV/VIII/XX/XXII. This study provided valuable data for broadening the ASFV antigen spectrum and identifying immunological targets for subunit vaccine formulation strategies. Full article

Cell cultures are an essential tool for laboratory diagnosis of porcine viral infections. However, interpreting the results requires considering the species and tissue origin of cell lines as well as the specific virus replication characteristics (cytopathic effect). This guide discusses the development of techniques for the primary isolation of viruses from biological material and provides recommendations for culturing viruses in different cell types. According to the World Organization for Animal Health, laboratory diagnosis should aim to isolate the virus in cell culture. We have studied the evolution of virus isolation methods for various diseases affecting pigs, including African swine fever virus (ASFV), classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), pseudorabies virus (Aujeszky’s disease, PRV), rotaviruses (RV), teschoviruses (PTVs), swine pox virus (SwPV), swine influenza A virus (IAVs), parvovirus (PPV), coronaviruses, circoviruses (PCVs), diseases with vesicular syndrome, and others. During our analysis of the literature and our own experience, we found that the porcine kidney (PK-15) cell line is the most suitable for isolating most viral porcine pathogens. For ASFV and PRRSV, the porcine alveolar macrophages (PAMs) continue to remain the primary model for isolation. These findings can serve as a starting point for virological reference laboratories to select optimal conditions for cultivating, obtaining field isolates, and strain adaptation. Full article

African swine fever virus (ASFV) is the only member of the family Asfarviridae and can cause African swine fever, a disease with a consistently high mortality rate. The pE248R protein, a myristoylated integral membrane protein of ASFV, is required for virus infectivity and some early postentry event, making it a key target for studying the prevention and treatment of ASFV. In this study, BALB/c mice were immunized with purified recombinant pE248R protein, leading to the generation of five monoclonal antibodies (mAbs). Selected mAbs were subsequently subjected to further characterization. By identifying the reactivity of different pE248R protein peptide segments with these monoclonal antibodies, we screened and identified a linear B cell epitope (⁸⁷QEVALTQWMDAG⁹⁸) on the pE248R protein. These results provide a new theoretical basis for analyzing the structure and function of pE248R protein, particularly contributing to the construction of a comprehensive B-cell epitope map for ASFV immunogens. Full article

African swine fever virus (ASFV) is a high-consequence pathogen that causes African swine fever (ASF), for which mortality rates can reach 90–100%, with death typically occurring within 14 days. ASF is currently a highly contagious pandemic disease responsible for extensive losses in pig production in multiple affected countries suffering from extended outbreaks. While a limited number of vaccines to prevent ASF are in use in south-east Asia, vaccines are not widely available, are only effective against highly homologous strains of ASFV, and must be used prior to an outbreak on a farm. Currently, there is no treatment for ASF and culling affected farms is the only response to outbreaks on farms to try and prevent spreading. CRISPR/Cas systems evolved as an adaptive immune response in bacteria and archaea that function by cleaving and disrupting the genomes of invading bacteriophage pathogens. CRISPR technology has since been leveraged into an array of endonuclease-based systems used for nucleic acid detection, targeting, genomic cleavage, and gene editing, making them particularly well-suited for development as sequence-specific therapeutic modalities. The programmability of CRISPR-based therapeutics offers a compelling new way to rapidly and specifically target pathogenic viral genomes simply by using different targeting guide RNAs (gRNA) as an adaptable antiviral modality. Here, we demonstrate for the first time a specific CRISPR/Cas9 multiplexed gRNA system that targets the African swine fever viral genome, resulting in sequence-specific cleavage, leading to the reduction in the viral load in infected animals, and subsequent recovery from an otherwise lethal dose of ASFV. Moreover, animals that recovered had protective immunity to subsequent homologous ASFV infection. Full article

African swine fever (ASF) is a highly fatal viral disease of domestic pigs and wild boar that continues to threaten pig production across Europe. Genotype II African swine fever virus (ASFV) has been present in Serbia since 2019 and was first confirmed in Bosnia and Herzegovina in 2023, yet recent genetic data from the region have been lacking. This study aimed to update the genetic characterization of ASFV strains circulating in Serbia between 2023 and 2025 and to provide the first sequence data from Bosnia and Herzegovina. A total of 110 isolates were analyzed by partial sequencing of seven genomic regions recommended by the European Union Reference Laboratory. Good-quality sequences were obtained for at least two loci per isolate. All isolates belonged to genotype II and were classified as CVR variant I, IGR-II, O174L-I, MGF I, K145R-I, and ECO2-II, corresponding to cluster 19. No novel genetic changes were identified in the sequenced fragments. These findings indicate the stable, endemic circulation of cluster 19 in both domestic pigs and wild boar, maintained through ecological and human-mediated transmission at the wildlife–livestock interface. The detection of cluster 19 in Bosnia and Herzegovina underscores transboundary spread and highlights the need for continued molecular surveillance and regional cooperation. Full article