Search Results (502)

The capsid protein pE120R of African swine fever virus (ASFV) is highly immunogenic and is thought to play an important role in viral replication, yet its molecular characteristics and functions during infection remain poorly understood. Here, we generated two monoclonal antibodies (mAbs), 1C11 and 3G7, against ASFV pE120R and characterized their specificity and utility. Epitope mapping showed that 1C11 recognized the linear epitope ¹⁰⁹KKHLFP¹¹⁴, whereas 3G7 recognized ¹¹²LFPKL¹¹⁶. These antibodies enabled analysis of pE120R expression and localization during ASFV infection, demonstrating that pE120R is expressed at a late stage and partially co-localizes with the structural protein p54 in viral factories. Together, these results provide valuable immunological tools for further investigation of pE120R in ASFV replication and pathogenesis. Full article

African swine fever (ASF) has become one of the most significant transboundary animal diseases affecting countries worldwide. Wild boars play a major role in virus persistence and in local spread through geographical contiguity, while long-distance and transboundary dissemination is more commonly associated with human-mediated activities, particularly the movement of contaminated pork products and materials. Hunting is frequently considered a central tool for disease control; however, its epidemiological impact remains debated. This review comparatively analyses the approaches adopted by countries of European continent affected by ASF, paying particular attention to the role of hunting within integrated management strategies. The review examines country-specific control measures, including surveillance systems, carcass search and removal, fencing, zoning, and population reduction policies. The analysis shows that successful eradication was associated with early detection, temporary suspension of hunting in infected core areas, rapid spatial containment through fencing, and intensive passive surveillance based on systematic carcass removal. Hunting was reintroduced only after containment, as a regulated depopulation tool under strict biosecurity supervision. In contrast, where the virus was already widespread at detection and containment measures were delayed or fragmented, intensified hunting alone did not prevent endemic persistence. These findings indicate that hunting is neither inherently protective nor detrimental; rather, its effectiveness depends on timing, coordination, and integration within a structured epidemiological framework. Effective control requires combining wildlife management with surveillance, biosecurity, and clear governance. Full article

The continuous and rapid spread of African swine fever (ASF) still poses a significant threat to Eurasian wild boar and domestic pigs, leading to substantial economic losses in all associated sectors annually. In Europe, including Germany, affected wild boar populations have become an important driver and host of ASF virus (ASFV), and monitoring and surveillance is key to tailor control measures that impede viral spread. While molecular methods are used to confirm the disease and to monitor viral evolution, serology gains importance in endemically affected regions as it provides insights into disease dynamics and possible attenuation of ASFV strains. Frontline serological diagnosis is done using ELISA assays, of which several are commercialized. However, accurate performance of ELISA assays is key for correct interpretation of wild boar samples. Due to the various stages of hemolysis and decay, field samples from wild boar can be challenging for ELISA assays. To assess which indirect or competitive ELISA kit performs best when dealing with such samples, we compared the sensitivity and specificity of four commercially available ELISA kits that are licensed in Germany, as well as three unlicensed but commercially available kits. For this comparison, we used all wild boar samples submitted to the National Reference Laboratory (NRL) for ASF in years 2021 and 2022, as well as samples from domestic pigs to have a control cohort where sample quality is optimal. We observed that wild boar samples, varying in stage of hemolysis and decay, were challenging for all kits included in this study. However, samples of domestic pigs were largely interpreted correctly by ELISA, using immunoperoxidase test as verification method. Additionally, the comparability of results obtained by regional laboratories was high. Our study provides data that highlights the importance of careful kit selection, assessment of sample quality, and data interpretation for effective ASFV surveillance and control. Full article

Background: African swine fever virus (ASFV) causes a fatal hemorrhagic disease in domestic pigs and wild boars. While live attenuated vaccines (LAVs) provide protection, their use raises safety concerns. Therefore, the aim of the present study was to identify viral B-cell antigens associated with protection and to test their potential using highly immunogenic vaccine delivery platforms. Methods: We employed a microarray of 169 ASFV proteins expressed in a cell-free prokaryotic system to identify immunodominant antigens using sera from immune pigs. Six structural proteins were selected and formulated into AP205 virus-like particles (VLPs). Additionally, replication-defective vesicular stomatitis virus (VSV)-based vaccine candidates expressing glycosylated CD2v and EP153R proteins were generated. Three groups of specific pathogen-free pigs were immunized with either VLP- or VSV-based vaccines and challenged with the virulent ASFV Georgia 2007 strain. Control groups included pigs immunized with the attenuated ASFV Estonia 2014 strain and a naïve group. Results: Most vaccine candidates induced detectable antibody responses against target ASFV proteins. However, neither VLP- nor VSV-based vaccines provided protection, as clinical scores, hematology, cytokine responses, and viremia levels were similar to those in the negative control group. In contrast, only the ASFV Estonia 2014 strain elicited a robust T-cell response and protective immunity. Conclusions: These findings highlight the challenges in identifying protective B-cell antigens of ASFV and emphasize the pivotal role of cellular immunity in mediating protection. Full article

African swine fever (ASF) is a contagious viral disease that causes severe economic losses in the global swine industry. Since its introduction to Vietnam in 2019, ASFV has evolved rapidly, with genotype II strains dominating initially and recombinant I/II variants emerging by 2023. Live attenuated vaccines (LAVs) have been developed and commercialized in Vietnam, including ASFV-G-ΔI177L, ASFV-G-ΔI177L/ΔLVR, and ASFV-G-ΔMGF, which confer homologous immune protection. Despite this, LAVs face challenges related to genetic stability, impossible protection against emerging recombinant strains, potential reversion to virulence, viral shedding, and safety in pregnant sows. ASFV’s ongoing evolution underscores the need for continuous genomic surveillance, evaluation of cross-protective efficacy, and implementation of biosecurity and DIVA strategies focused more on evaluating vaccine efficacy than safety. This review summarizes the current molecular epidemiology of ASFV in Vietnam after vaccines were licensed for use, the development and performance of commercial LAVs, and the practical challenges of their application in endemic settings, and provides insights for informed vaccine deployment and integrated ASF control strategies in rapidly evolving viral landscapes. Full article

African swine fever (ASF), a highly contagious and lethal viral disease caused by the African swine fever virus (ASFV), poses a severe threat to the global swine industry. Recent outbreaks across Asia, Europe, and the Caribbean are exacerbating the challenge. Current control measures rely mainly on early detection, culling and strict biosecurity practices, underscoring the urgent need for a safe and effective vaccine. Since the mid-1960s, diverse vaccine strategies, including inactivated, subunit, DNA/mRNA, vectored, and live attenuated virus (LAV) vaccines, have been explored. Inactivated vaccines have consistently failed to confer protection due to insufficient functional antigen presentation and weak cellular immune activation. Subunit vaccines targeting single or multiple ASFV antigens have also shown limited success, often failing to induce sterile or long-lasting immunity. Among these approaches, LAV vaccines have demonstrated the greatest promise in eliciting robust and durable immune responses. However, major knowledge gaps remain regarding ASFV biology, ASFV–host interactions, ASFV immune evasion mechanisms, protective and cross-protective immunity, stable cell lines for LAV production, virulence reversion of LAVs, and the lack of harmonized standards for evaluating vaccine safety and efficacy, all of which impede the development of safe and broadly effective ASF vaccines. This narrative review summarizes recent advances in ASF vaccine research and highlights the critical obstacles that must be overcome to achieve successful ASF vaccine development. Full article

The accelerating frequency of emerging infectious diseases (EIDs) in livestock poses a significant threat to global food security, as well as to animal and public health. While wastewater-based surveillance (WBS) has advanced significantly for human health surveillance, its application to livestock production systems remains fragmented and lacks standardization. This review synthesizes current evidence on livestock wastewater-based surveillance (L-WBS) as an early-warning sentinel for emerging viral pathogens, evaluating their dynamics, economic impacts, biosecurity measures, and One Health implications. Existing studies demonstrate that L-WBS effectively detects emerging viral pathogens in agricultural effluent, swine manure, and municipal wastewater systems serving livestock regions, frequently preceding clinical outbreak recognition. We further conceptualized a multifactorial framework linking environmental drivers such as climate and ecological disruption and agricultural intensification to pathogen emergence dynamics. Economic assessments show substantial direct losses (approximately US$ 950 per H5N1-infected dairy cow and US$ 25.9 billion in African swine fever virus (ASFV)-related damages across China) alongside indirect costs from biosecurity implementation, workforce disruption, and supply-chain instability. We recommend prioritizing methodological standardization through unified sampling and extraction protocols, integration of next-generation sequencing for genomic surveillance, and cross-sectoral policy frameworks to operationalize L-WBS as a global early-warning infrastructure for mitigating zoonotic spillover and livestock-dependent community resilience. Full article

African swine fever (ASF) has been a persistent threat to Eurasian pig populations since its emergence in 2007. The disease has become endemic in numerous countries, including Poland, Germany, Romania, Hungary, Italy, the Philippines, and several others. Epidemiological data reveals that over 99% of outbreaks are attributed to a highly virulent hemadsorbing virus belonging to genotype II. Traditional genotyping methods, primarily relying on the B646L gene, have faced significant limitations in providing a comprehensive understanding of virus dissemination patterns. Previous attempts to identify a universal marker for tracking virus spread through analysis of the CVR locus of the B602L gene and the I73R/I329L locus failed to produce a coherent picture of the virus’s geographical distribution across Eurasia. To address these challenges, a comprehensive study was conducted involving the analysis of 250 ASFV isolates/strains from 25 countries across Europe and Asia between 2007 and 2024. This research led to the development of a novel sub-genotyping algorithm for ASFV genotype II. The study identified four topotypes: «CAU1», «EU1», «EU2», and «ASIA1». Within these topotypes, 31 genetic lineages were detected, each characterized by specific single-nucleotide polymorphisms (SNPs). Based on the comparison of two methods of sub-genotyping Eurasian ASFVs—the classification by Gallardo C. et al. (2023) based on genetic variations of 6 loci, and the proposed classification into topotypes and genetic lineages using whole-genomes—it was established that the multigenic approach has insufficient resolution. At the same time, significant differences were observed at the level of whole-genomes. The creation of a new spatiotemporal classification has significant applications in international surveillance of ASF outbreaks, local disease monitoring, and investigation of new infection cases. Full article

The regulatory mechanisms of collagen formation and cell adhesion pathways during African Swine Fever Virus (ASFV) infection remain poorly understood. This study aims to investigate whether ASFV manipulates these pathways by targeting host transcriptional regulators. Through weighted Kendall correlation analysis of transcription factor binding sites (TFBSs) in differentially expressed genes (DEGs) from the lung tissue of ASFV-recovered pigs, we identified SP2 and KLF6 as key transcription factors (TFs) associated with collagen synthesis and cell adhesion, respectively. Domain–domain interaction prediction, followed by Förster resonance energy transfer (FRET) assays, confirmed that the ASFV proteins R238L and R298L directly bind to the zf-C2H2 domains of SP2 and KLF6. Furthermore, overexpression of R238L and R298L in HeLa and 3D4/21 cells significantly downregulated SP2 and KLF6 target genes involved in these pathways. Our findings reveal a novel mechanism by which ASFV proteins R238L and R298L interfere with host transcription factors SP2 and KLF6, potentially disrupting collagen matrix integrity and cell adhesion to facilitate viral pathogenesis. Full article

African swine fever virus (ASFV) causes a fatal disease in domestic pigs and wild boars (Sus scrofa), leading to nearly 100% mortality during acute infection and significant economic losses in swine production. Unlike other eukaryotic viruses, ASFV encodes a histone-like nucleic acid-binding protein, pA104R, which is highly conserved and present in all described ASFV isolates of different genotypes. Moreover, A104R-like sequences have been identified in the genomes of soft ticks, which can replicate and transmit ASFV. Using a virulent genotype IX field isolate from Kenya, we analyzed the importance of A104R for viral replication in a permissive wild boar cell line (WSL). In this study, we confirmed that A104R is not essential for in vitro replication of ASFV. Loss of A104R did not detectably affect viral DNA replication or RNA transcription but led to a moderate reduction in virus titers and plaque sizes. Substitution of A104R with a similar ASFV-like element derived from the genome of an Ornithodoros moubata soft tick was not capable of rescuing the deletion mutant phenotype. In contrast, reintroduction of the authentic A104R open reading frame (ORF) into the deletion mutant fully restored wild-type virus growth properties. In accompanying studies, we verified the DNA-binding activities of the ASFV- and tick-derived A104R proteins and performed mass spectrometric analyses of the pA104R interactome. These experiments revealed, besides DNA-dependent co-precipitated proteins, specific DNA-independent protein–protein interactions of pA104R with other viral and cellular proteins. Full article

Background/Objectives: African swine fever is currently the most devastating viral disease affecting domestic and wild suids, causing major economic losses and severe impacts on natural populations. Oral immunization could become an important tool to control the panzootic and support wild pig conservation. However, this requires safe and effective vaccines, baits accepted by target species, and vaccine reservoirs that reliably release the vaccine during bait intake while maintaining vaccine integrity. Methods: We evaluated different bait types and vaccine containers in four wild Suiformes species, including Eurasian wild boar. In the same wild boar, we assessed oral vaccination with the live attenuated vaccine candidate “ASFV-G-ΔI177L”. Environmental monitoring approaches were applied to detect potential virus shedding, and vaccine immunogenicity and dissemination were evaluated. Vaccine stability was tested in vitro in two container types under different temperature conditions. Results: Bait uptake and container performance varied between manufacturers and among species. Environmental samples were largely negative for vaccine virus genome under controlled laboratory conditions, with only a few positive cotton ropes (0.43% of all samples). After oral bait vaccination, 45% (9/20) of wild boar seroconverted, with a higher proportion in animals receiving the vaccine in the slightly less attractive bait (gelatine-based). Vaccine virus dissemination was limited to a small number of organs, including gastrohepatic and mandibular lymph nodes. Conclusions: Our findings demonstrate that wild pigs can be vaccinated orally with “ASFV-G-ΔI177L” while virus shedding appears minimal. Although the tested baits show potential for multiple target species, baits and containers require optimization. Environmental monitoring methods also need refinement for field application. Full article

Background/Objectives: African swine fever virus (ASFV), the causative agent of African swine fever (ASF), is a highly contagious virus affecting both domestic and feral pig populations with mortality rates approaching 100% within one week of infection. Currently, there are limited treatments or vaccines available to control the disease. Although ASF is endemic in sub-Saharan Africa, the virus has also spread widely, reaching regions of the European Union, Russia, China, Southeast Asia, and, more recently, to the Dominican Republic and Haiti, bringing the threat closer to the United States (U.S.). ASF introduction to the U.S. would have severe consequences for swine producers and the national pork industry. Consequently, there is an urgent need to develop effective vaccine strategies to manage ongoing outbreaks abroad and mitigate the risk of future ASF incursions. Recent efforts have identified several ASFV epitopes and evaluated them in experimental vaccine trials. However, these vaccine candidates have elicited limited protective immune responses and have not demonstrated full protective efficacy. Methods: In this study, we employed in silico modeling and epitope prediction tools to design a synthetic multiepitope ASF protein incorporating key immunogenic regions of ASFV. The goal was to generate a single-antigen construct capable of inducing broad and robust immune responses when formulated with an established nanoparticle-based vaccine platform. The multiepitope ASF protein was subsequently expressed and entrapped into mannose-conjugated chitosan (M-CS) nanoparticles for vaccine formulation. The candidate vaccine, formulated with M-CS nanoparticle-entrapped adjuvant (ADU S100), was administered intramuscularly to pigs, and both T- and B-cell responses were assessed following the primary (DPV 22) and booster (DPV 42) doses. Results: Our M-CS ASF protein vaccine elicited antigen-specific T- and B-cell responses, both of which are recognized as central correlates of protection against ASFV. Conclusions: These promising preliminary immunological findings suggest that this nanoparticle vaccine has the potential to confer protection against ASFV challenge, a hypothesis that will be examined in future studies. Full article

African swine fever virus (ASFV) is a highly contagious and lethal double-stranded DNA virus that relies on host cellular translation machinery for replication and immune evasion. The multigene family 110 (MGF110) contains several members with incompletely defined functions. Here, the role of MGF110-7L in host translation regulation was investigated in HEK-293T and PK15 cells. Ribopuromycylation assays demonstrated that MGF110-7L expression resulted in potent, dose- and time-dependent inhibition of nascent polypeptide synthesis. Western blotting revealed a selective reduction in eIF4G1 protein abundance, with no significant changes in eIF4G2, eIF4E, and eIF4A, while eIF4G1 mRNA levels remained unaffected, indicating post-transcriptional regulation. Overexpression of eIF4G1 partially rescued translation suppression. MGF110-7L also decreased eIF4B phosphorylation and activated the PERK/eIF2α pathway, consistent with the induction of endoplasmic reticulum (ER) stress. ER stress promoted stress granule (SG) formation and enhanced eIF4G1 association with the SG marker G3BP1. The inhibitor assays demonstrated that the suppression of eIF2α phosphorylation by ISRIB restored the abundance of eIF4G1 protein. In addition, the downregulation of eIF4G1 was reversed by the inhibition of autophagy using bafilomycin A1, indicating an SG-linked autophagy–lysosome degradation pathway. Co-immunoprecipitation assays confirmed increased eIF4G1-G3BP1 interaction, but no direct binding between MGF110-7L and eIF4G1. This work provides the first experimental evidence that an ASFV protein, MGF110-7L, suppresses cap-dependent translation through SG-mediated autophagic degradation of eIF4G1, thereby revealing a previously unrecognized mechanism of ASFV translational control. These findings not only extend current understanding of ASFV–host interactions but also suggest potential molecular targets for antiviral strategies and rational vaccine design. Full article

Transboundary animal diseases (TADs) pose persistent threats to global livestock production, and chemical disinfection remains a critical component of biosecurity. However, virucidal efficacy is commonly assessed using single-condition endpoints, limiting comparative interpretation across biologically heterogeneous viruses. In this study, an experimental framework explicitly structured across virus species, disinfectant concentration, and contact time was applied to systematically compare virucidal response patterns across four major TAD viruses—avian influenza virus, African swine fever virus, foot-and-mouth disease virus, and lumpy skin disease virus. Four representative disinfectant active ingredients from distinct chemical classes were evaluated across multiple concentrations and defined contact times using quantitative suspension assays. Virucidal efficacy was quantified using log₁₀ reduction values, and critical concentrations required to achieve ≥4 log₁₀ reduction were derived for comparative analysis. Distinct concentration–response profiles were observed among disinfectant classes, with some ingredients showing relatively consistent activity across viruses, while others exhibited pronounced virus-specific thresholds. Notably, enveloped viruses did not uniformly display higher susceptibility, and extension of contact time enhanced efficacy predominantly in an ingredient-dependent manner. To integrate these multifactorial outcomes at the virus level, a quartile-based analysis was applied, providing a conservative indicator of relative viral resistance across disinfectants and exposure conditions. Overall, these findings demonstrate that virucidal susceptibility is shaped by interactions between disinfectant chemistry and exposure parameters, and support concentration–time-resolved, pattern-based evaluation frameworks—supplemented by quartile-based resistance ranking—beyond single-condition endpoints for assessing disinfectant efficacy against animal viruses. Full article

African swine fever (ASF), caused by the African swine fever virus (ASFV), is a highly contagious and fatal disease. Accurate detection in the early stages of an outbreak relies on molecular methods, but serological monitoring at the population level is also crucial for assessing the extent of exposure and past infections. This experiment developed an indirect enzyme-linked immunosorbent assay (ELISA) to detect antibodies against ASFV, using three ASFV RNA polymerase subunits (H359L, C147L, and D339L) as coating antigens. The recombinant proteins were successfully expressed in Escherichia coli and purified. Using a checkerboard titration method, we systematically optimized key assay parameters, determining the optimal coating conditions to be a mixture of H359L, C147L, and D339L at a volume ratio of 1:2:2, with individual concentrations of 1 μg/mL, 0.4 μg/mL, and 0.5 μg/mL, respectively. Other optimized parameters included a serum dilution of 1:200, a blocking buffer containing 5% skim milk, and specific incubation conditions for the secondary antibody and substrate. The cut-off value was established at 0.430 ($\overline{x}$ + 4SD) based on 30 negative sera. The established triple-antigen indirect ELISA exhibited high sensitivity (detecting positives at dilutions up to 1:3200) and excellent specificity (no cross-reactivity with antisera against CSFV, PRRSV, PRV, PCV2, and PEDV. Both intra and inter assay repeatability were confirmed, with coefficients of variation ranging from 1.020% to 7.600%. Validation with 123 clinical serum samples demonstrated a 96.75% concordance rate with a commercial kit. In conclusion, the three-antigen indirect ELISA established in this study exhibits high specificity and sensitivity, making it suitable for serological surveillance and exposure assessment of ASFV antibodies. It can be combined with molecular detection for epidemiological investigations and integrated prevention and control measures. Full article