Search Results (180)

This study aimed to evaluate effect of Gordonia alkanivorans on phagocytic activity of porcine alveolar macrophages (PAMs) and immune function in piglets. Quantitative PCR and fluorescence tracing were used to measure phagocytic efficiency of G. alkanivorans-intervened PAMs against PRRSV and E. coli. Sixty-four 45-day-old cross-bred piglets with equal sex were randomly divided into four groups (n = 16/group). Growth performance, immune function, and intestinal flora were analyzed. G. alkanivorans extract exhibited half cytotoxic concentration of 36.43 mg/mL, half effective concentration of 0.1009 mg/mL, and half inhibitory concentration of 0.0043 mg/mL in PAMs, significantly increasing their phagocytic efficiency by 98.5% against PRRSV and 2.31- to 13.46-fold against E. coli. Dietary supplementation with G. alkanivorans elevated antibody-positive rates against classical swine fever virus (47.92%) and pseudorabies virus (14.58%), modified serum cytokine: Interleukin (IL)-1β, IL-2, Tumor Necrosis Factor -α, Interferon (IFN)-α, IFN-γ, IL-4, and IL-10 (−144.51% to +191.72%). It increased intestinal operational taxonomic units by 152%, the Shannon index by 14.62%, and the Chao index by 11.37%, while reducing the Firmicutes/Bacteroidetes ratio by 713.90%. In conclusion, G. alkanivorans enhances immunity and antiviral activity in piglets by gut and immune regulation. Full article

Classical swine fever virus (CSFV) remains a significant threat to the global swine industry, causing a highly contagious and often fatal disease in pigs. This review comprehensively examines the molecular biology of CSFV and the intricate mechanisms it employs to establish infection. We detail the structure and functions of viral proteins, highlighting their roles in virus entry, replication, and immune evasion. A major focus is placed on the virus–host interaction, specifically how CSFV subverts host innate immune responses and hijacks critical cellular processes, including metabolism and cell death pathways. The virus strategically manipulates host cell death programs (apoptosis, mitophagy, necroptosis) and exploits intracellular transport systems to promote its propagation. Furthermore, we summarize recent advances in understanding the cellular receptors involved in CSFV entry and the role of exosomes in viral spread. This synthesis of current knowledge aims to provide a deeper insight into the pathogenesis of CSFV and identify potential vulnerabilities that could be targeted for the development of novel antiviral strategies. Full article

Pestiviruses, such as bovine viral diarrhea virus (BVDV) or classical swine fever virus (CSFV), are members of the family Flaviviridae and infect a broad range of species, causing significant economic losses in livestock. A unique feature of pestiviruses is the E^rns protein, which is part of the glycoprotein complex at the surface of the virion, but it is also secreted as an RNase that functions as an interferon (IFN) antagonist. This dual nature makes E^rns a particularly complex and multifunctional protein, highlighting its importance for understanding pestivirus biology. Bungowannah pestivirus (BuPV) was reported to exhibit high genetic plasticity, making it suitable for engineering recombinant tools. In this study, we generated a recombinant BuPV expressing green fluorescent protein (GFP) fused to the N-terminus of the E^rns protein from BVDV. The GFP-E^rns fusion was detected by fluorescence microscopy and remained stable across five serial passages. The recombinant virus infected all tested mammalian cell lines but replicated more slowly than the parental BuPV stock. RNase activity assays confirmed retention of enzymatic function. These results demonstrate stable expression, broad infectivity, and preserved activity of GFP-E^rns in the recombinant BuPV, indicating that this might be a useful tool for further investigations on pestivirus pathogenesis. Full article

Background: Highly potent vaccines are essential for the effective control of classical swine fever (CSF). Since CSF re-emerged in 2018 in Japan, the live CSF virus (CSFV) vaccine—a guinea pig exaltation of Newcastle disease virus-negative strain vaccine (GPE⁻, genotype 1.1)—has been applied to domestic pigs, contributing to a reduction in outbreaks. Meanwhile, the persistence and continued expansion of CSFV in wild boar populations have raised concerns regarding potential antigenic divergence. Methods: We systematically evaluated the neutralizing reactivity of sera from GPE⁻-vaccinated pigs against CSFV strains (genotype 2.1) recently circulating in Japan against identified a representative strain that showed markedly reduced neutralization. We directly assessed the protective efficacy of the GPE⁻ vaccine against this strain in a controlled challenge experiment. At 4 weeks post-vaccination, both vaccinated and unvaccinated pigs were orally challenged with the representative Japanese strain and monitored for 3 weeks thereafter. Results: Among the Japanese CSFV strains, the JPN/SM/WB/2022 isolate exhibited markedly reduced neutralizing reactivity—over 32-fold lower than that against the vaccine strain—when tested with GPE⁻ vaccine-induced antisera. In the experimental infection in pigs, unvaccinated pigs exhibited typical clinical signs of CSF and viremia, and two pigs reached the humane endpoint. In contrast, none of the vaccinated pigs showed any clinical signs of infection. Robust humoral and cellular immune responses were induced in vaccinated pigs, which may correlate with the observed complete protection. Conclusions: The GPE^– live vaccine provides protective immunity against an antigenically distinct strain, prevents disease, and limits viral spread in domestic pigs. Full article

The global swine industry suffers persistent economic losses and health challenges due to major viral pathogens such as African swine fever virus (ASFV), porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV), and porcine circovirus (PCV). Traditional diagnostic methods, including virus isolation, serology, and quantitative PCR (qPCR), are limited by time, equipment requirements, and field applicability. Recent advances in CRISPR-based diagnostics, particularly those leveraging the collateral cleavage activity of Cas12a and Cas13a, have enabled rapid, sensitive, and field-deployable nucleic acid detection. This review outlines the principles of CRISPR-Cas12a/13a systems, their integration with isothermal amplification techniques, and their application in detecting major swine viruses. Cas12a-based platforms (e.g., DETECTR) and Cas13a-based systems (e.g., SHERLOCK) achieve detection limits as low as single-copy/μL within 25–60 min at 37 °C, offering high specificity and compatibility with visual readouts. Applications include ASFV, PRRSV, CSFV, PCV, foot-and-mouth disease virus (FMDV), porcine rotavirus (PoRV), and porcine parvovirus 7 (PPV7). Despite significant advances, challenges remain, notably the reliance on nucleic acid extraction and the need for fully integrated “sample-in, result-out” systems. Ongoing innovations in extraction-free methods, lyophilized reagents, and multiplex detection will strengthen the role of CRISPR diagnostics in swine disease surveillance and control. From an application standpoint, the technology offers a low-capital, field-adaptable alternative to qPCR, with its value proposition rooted in early outbreak containment and loss prevention. Its adoption pathway is expected to vary across production systems—serving as a sentinel tool in intensive settings, a leapfrogging solution in rapidly intensifying regions, and through shared-service models in resource-limited contexts. However, translation to routine use still requires overcoming standardization hurdles, regulatory validation, and workflow integration. Full article

Curcumin, the major polyphenolic constituent of Curcuma longa, has been widely investigated as a hepatoprotective adjunct due to its antioxidant and immunomodulatory properties. This review evaluates the relevance of curcumin for the prevention and management of liver dysfunction and hepatitis in pigs by synthesizing available porcine evidence and integrating mechanistic insights from translational liver injury models where pig-specific data remain limited. Across experimental hepatic injury contexts, curcumin administration is most consistently associated with reduced biochemical and structural indicators of hepatocellular damage, including decreased aminotransferase activity, attenuation of lipid peroxidation, and enhancement of endogenous antioxidant defenses. These effects are mechanistically linked to suppression of pro-inflammatory signaling pathways, particularly NF-κB-related transcriptional activity and inflammasome-associated responses, together with reduced expression of key cytokines such as TNF-α, IL-1β, and IL-6. Concurrent activation of Nrf2-centered cytoprotective pathways and induction of phase II antioxidant enzymes (including HO-1, GST, and NQO1) appear to constitute a conserved axis supporting hepatic oxidative stress resilience. In swine-relevant infectious settings, available data further support antiviral activity against selected porcine pathogens, including classical swine fever virus and porcine reproductive and respiratory syndrome virus, potentially mediated through interference with lipid-dependent stages of viral replication and modulation of Kupffer cell activation. Although combination strategies with established hepatoprotective approaches are conceptually attractive, current synergy evidence remains heterogeneous and largely extrapolated. Overall, curcumin represents a plausible adjunct candidate for supporting porcine liver health; however, translation into practice will depend on resolving formulation-dependent bioavailability constraints and strengthening the pig-specific evidence base. Full article

Wild boars inhabit fields, hills, and farms across Japan, where they are fed on by numerous arthropods, including mosquitoes and ticks. Consequently, they are frequently exposed to arthropod-borne pathogens. In Toyama Prefecture, blood samples from captured wild boars have long been collected for classical swine fever virus antibody testing, with detailed records kept on the capture locations. In this study, we investigated the prevalence of antibodies against Japanese encephalitis virus (JEV) and severe fever with thrombocytopenia syndrome virus (SFTSV) using 3059 serum samples collected from wild boars over the past six years. A previously developed single-round infectious particles (SRIPs) assay system was employed for the analysis. We also examined the geographic distribution of antibody-positive wild boars. The results showed that antibody positivity rates for both JEV and SFTSV increased annually from 2019 to 2024. Geographical analysis revealed that JEV antibody-positive wild boars were distributed throughout Toyama Prefecture, whereas SFTSV antibody-positive wild boars were concentrated mainly in the northwestern region and along the western prefectural border. These findings suggest that JEV continue to pose an infection risk across the entire prefecture, while SFTSV has been actively spreading in the northwestern area during 2023–2024, raising concern over an increasing risk of human infection. Full article

Host factors play critical roles in viral IRES-mediated translation by modulating the efficiency and specificity of viral protein synthesis. In this study, we used small interfering RNA (siRNA) treatment to silence and plasmid-based expression to overexpress PKD1L3 and USP31. Silencing PKD1L3 and USP31 suppressed IRES activity in FMDV and CSFV RNAs, whereas the overexpression of PKD1L3 did not have a significant effect, and USP31 overexpression resulted in only a modest increase in CSFV-IRES activity. Silencing PKD1L3 significantly reduced EMCV-IRES activity but had no significant effect on HCV- or DENV-IRES activity, and silencing USP31 had no significant effect on the activities of these three IRESs. Notably, the combined overexpression of PKD1L3 and USP31 significantly suppressed HCV-IRES activity, suggesting potential context-dependent interactions. These findings indicated that PKD1L3 and USP31 contribute more prominently to CSFV-, FMDV-, and EMCV-IRES-mediated translation than to HCV- or DENV-IRES-driven translation. Collectively, our results provide new insights into the host factors involved in IRES-mediated viral translation, establish a foundation for future in vivo studies to elucidate the specific roles of PKD1L3 and USP31 during viral infection, and indicate potential strategies for mitigating these viruses. 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

Background/Objectives: Classical swine fever (CSF) is listed by the World Organisation for Animal Health as a highly devastating and contagious pig disease, causing severe economic losses to the swine industry. In spite of the successful elimination of CSF in Taiwan, preparedness against potential reintroduction remains essential. The live attenuated vaccines have been effective in disease control, but are not capable of a viable strategy that differentiates infected from vaccinated animals (DIVA). Subunit vaccines are recognized for their safety and ability to induce protective immunity against infectious diseases. Methods: In this study, the recombinant CSF virus (CSFV) E2 proteins were formulated with a CpG motif as an adjuvant to produce the E2-CpG subunit vaccine. Its efficiency in specific-pathogen-free (SPF) pigs was compared with a commercially available E2 subunit vaccine (Bayovac^® CSF-E2; Bayer Taiwan Co., Ltd., Taipei City, Taiwan). Results: Significantly higher titers of anti-E2 antibodies were induced in pigs immunized with a single dose of the E2-CpG vaccine, particularly the reduced E-0.5A formulation, than those immunized with a dose of the commercialized E2 subunit vaccine adjusted to double dosage. This designed subunit vaccine showed high efficacy in protection against clinical symptoms and significant pathological alterations in pigs after a highly virulent CSFV (genotype 1.1) challenge. Viral shedding was not detected in vaccinated pigs before completion of the challenge study, and the viral load in their spleens remained undetectable. Conclusions: These results could support the potential of the E2-CpG vaccine as a cost-effective, single-dose subunit vaccine capable of inducing robust CSFV-specific immunity and providing 100% protection against lethal CSFV challenges. Full article

Background: Classical swine fever virus (CSFV) is a highly contagious and fatal disease in pigs and wild boars. While hunting and bait vaccination are effective for CSFV eradication, additional strategies are needed to control wild boar populations. This study aimed to develop an oral vaccine, Flc-LOM-GnRHx3, by inserting gonadotropin-releasing hormone (GnRH) epitopes into the Flc-LOM clone. Methods: The Flc-LOM-GnRHx3 strain was rescued from CPK cells and propagated to high titers in MDBK cells. Male boars (20 weeks old) received three doses (10^5.0 TCID₅₀/ml/dose) of Flc-LOM-GnRHx3 either orally or intramuscularly at 2-week intervals. Anti-CSFV E2 antibodies were detected via immunofluorescence and Western blotting. Results: Both vaccination routes induced anti-GnRH antibodies and reduced testosterone levels. Testis size and weight were slightly lower than controls, with seminiferous tubule and spermatid deformities observed in 52.5% of intramuscularly vaccinated pigs and 20.8% of orally vaccinated pigs. Conclusions: Flc-LOM-GnRHx3 demonstrates potential as a dual-function oral vaccine that can eradicate CSFV and impair reproductive capacity in wild boars, offering a novel approach for integrated disease control and population management. Full article

Classical swine fever (CSF) is a highly contagious and lethal disease caused by classical swine fever virus (CSFV), and it is also a notifiable disease according to the World Organization for Animal Health. Owing to the continuous growth of the international trade in pigs and pig products, pig farming has become the pillar industry of the global livestock industry and is the most important source of animal protein for mankind. As a single-stranded RNA virus, CSFV can avoid being recognized and cleared by the host immune system through a variety of immune evasion strategies so that it persists in the host body and causes multisystemic pathology. CSF has also become one of the most serious infectious diseases affecting the pig industry, resulting in considerable economic losses to the pig industry. Therefore, understanding the main immune evasion mechanism of CSFV is very important for the prevention and control of CSF infection. This article reviews the main immune evasion mechanisms of CSFV, including the suppression of nonspecific immune responses; evasion of adaptive immune responses; and the regulation of host cell apoptosis and cell autophagy. CSFV affects type I interferon regulatory signals; the JAK-STAT signaling pathway; the RIG-I and NF-κB signaling pathways; immune cell function; the mitochondrial apoptosis pathway; and the endoplasmic reticulum stress apoptosis pathway; the PI3K-Akt signaling mediated AMPK-mTOR macroautophagy pathway through its structural proteins E^rns and E1 and E2; and the nonstructural proteins N^pro, NS4B, and NS5A to achieve immune evasion. As our understanding of CSFV immune strategies continues to deepen, we believe that this understanding will provide new strategies for the development of new vaccines and novel diagnostic methods in the future. Full article

African swine fever virus (ASFV) and classical swine fever virus (CSFV) are important transboundary animal diseases (TADs) affecting swine. ASFV is a large DNA virus with a genome size of 170–190+ kilobases (kB) belonging to the family Asfarviridae, genus Asfivirus. CSFV is a single-stranded RNA virus with a genome size of approximately 12 kB, belonging to the family Flaviviridae, genus Pestivirus. Outbreaks involving either one of these viruses result in similar disease syndromes and significant economic impacts from: (i) high morbidity and mortality events; (ii) control measures which include culling and quarantine; and (iii) export restrictions of swine and pork products. Current detection methods during an outbreak provide minimal genetic information on the circulating virus strains/genotypes that are important for tracing and vaccine considerations. The increasing availability and reduced cost of next-generation sequencing (NGS) allow for the establishment of NGS protocols for the rapid identification and complete genetic characterization of outbreak strains during an investigation. NGS data provides a better understanding of viral spread and evolution, facilitating the development of novel and effective control measures. In this study, panels of primers spanning the genomes of ASFV and CSFV were independently developed to generate approximately 10 kB and 6 kB amplicons, respectively. The primer panels consisted of 19 primer pairs for ASFV and 2 primer pairs for CSFV, providing whole genome amplification of each pathogen. These primer pools were further optimized for batch pooling and thermocycling conditions, resulting in a total of 5 primer pools/reactions used for ASFV and 2 primer pairs/reactions for CSFV. The ASFV primer panel was tested on viral DNA extracted from blood collected from pigs experimentally infected with ASFV genotype I and genotype II viruses. The CSFV primer panel was tested on 11 different strains of CSFV representing the three known CSFV genotypes, and 21 clinical samples collected from pigs experimentally infected with two different genotype 1 CSF viruses. ASFV and CSFV amplicons from optimized PCR were subsequently sequenced on the Oxford Nanopore MinION platform. The targeted protocols for these viruses resulted in an average coverage greater than 1,000X for ASFV, with 99% of the genome covered, and 10,000X–20,000X for CSFV, with 97% to 99% of the genomes covered. The ASFV targeted whole genome sequencing protocol has been optimized for genotype II ASF viruses that have been responsible for the more recent outbreaks outside of Africa. The CSFV targeted whole genome sequencing protocol has universal applications for the detection of all CSFV genotypes. Protocols developed and evaluated here will be essential complementary tools for early pathogen detection and differentiation, as well as genetic characterization of these high-consequence swine viruses, globally and within the United States, should an outbreak occur. Full article

Despite intensive eradication efforts, classical swine fever (CSF) remains endemic across South America, Europe, Asia, and the Caribbean, highlighting the need for more effective surveillance and detection methods. Reverse-transcription real-time polymerase chain reaction (RRT-PCR) is the fastest, and most sensitive assay for detecting CSF virus (CSFV) genomic material. Previously, we demonstrated that spleen swabs outperformed spleen homogenates for the detection of ASFV genomic material by RRT-PCR. In this study, we compared CSFV genome detection in paired spleen homogenates and spleen swabs generated using 49 frozen and 33 fresh spleen samples collected from experimentally inoculated pigs with acute infection. The results show that the CSFV genome detection in spleen swabs is comparable to that in spleen homogenates. The study also demonstrated that the CSFV genomic material can be detected in spleen swabs during early CSFV infections, and the viruses can be successfully isolated from the swabs. The use of spleen swabs instead of spleen tissue homogenates for CSF detection will reduce labor, decrease costs associated with reporting, and increase the diagnostic throughput. Full article