Search Results (1,365)

SARS-CoV-2 infection has emerged worldwide. To reduce the number of cases and limit the transmission of the virus, health and local authorities have implemented several strategies. Mass screening is a key strategy for mitigating the damage caused by this pandemic. This strategy is based on the use of qRT-PCR and pooling to diagnose SARS-CoV-2 infection. The present work explores the performance and limitations of this strategy for the molecular diagnosis of SARS-CoV-2 infection. Three important technical aspects were retained: the comparison of two commercial extraction kits (BIGFISH and BIOER), the simulation of a non-compliant nasopharyngeal swab, and the evaluation of the pooling strategy. A total of 97 SARS-CoV-2-positive nasopharyngeal samples were used. The comparison of the two extraction kits was based on threshold cycles (Ct) values. The results showed a significant difference (IC = 95%) in the Ct of the nucleocapsid gene (N; p = 0.0000384) and RNA-dependent RNA polymerase (RdRp; p = 0.0254). However, no significant difference was observed between the Internal Control gene (IC; p = 0.0723) and Envelope gene (E; p = 0.150). The Ct values resulting from the BIGFISH extraction kit were generally lower than those obtained from BIOER. In terms of sensitivity, the RT-qPCR technique allows for the detection of viral RNA up to 10⁻³ as a dilution factor. This study demonstrated that the pooling strategy is an effective diagnostic technique. Positive samples remained detectable even in pools of 1000 or even 10,000 samples. However, the size of the pool under diagnostic conditions should not exceed a limit that must be dynamically adapted to prevalence to ensure economic and analytical viability. Full article

Encephalomyocarditis virus (EMCV) belongs to the genus Cardiovirus of the family Picornaviridae. It is a non-enveloped, positive-sense, single-stranded RNA virus and an important pathogen causing encephalomyocarditis (EMC). Tripartite motif 13 (TRIM13) is a member of the tripartite motif (TRIM) family and serves as an important effector molecule in antiviral innate immunity. However, its antiviral activity and underlying molecular mechanisms during EMCV infection remain unknown. In this study, we identified TRIM13 as a regulator of NF-κB activation. TRIM13, dependent on its E3 ubiquitin ligase activity, directly binds to IκBα and dose-dependently increases its phosphorylation level. To determine the chain type of IκBα polyubiquitination, antibodies specific for K48-linked and K63-linked ubiquitin were used. Our data indicated that IκBα was subjected to polyubiquitination independent of K48 and K63 linkages. This interaction promotes non-K48/K63-linked polyubiquitination of IκBα, thereby inducing NF-κB nuclear translocation. Subsequently, nuclear NF-κB activates the secretion of pro-inflammatory cytokines, exacerbating inflammatory responses and ultimately facilitating EMCV infection. Full article

Background/Objectives: Bovine viral diarrhea (BVD) is a major infectious disease of cattle caused by bovine viral diarrhea virus genotypes 1 and 2 (BVDV-1 and BVDV-2). Current inactivated and live attenuated vaccines provide incomplete cross-genotype protection and may exhibit limitations related to durability of immunity or safety. This study evaluated whether co-expression of the BVDV envelope glycoproteins E1 and E2 in a Modified Vaccinia Ankara (MVA) vector could support antigen expression and induce immune responses in a proof-of-concept model. Methods: Recombinant Modified Vaccinia Ankara (MVA) viruses expressing BVDV-1 E1E2 or BVDV-2 E1E2 were generated by homologous recombination. Recombinant viruses were purified and characterized for antigen expression, genetic stability, and growth properties in vitro. Immunogenicity was evaluated in a BALB/c mouse model by measuring E2-specific antibody responses, virus-neutralizing antibodies, and antigen-responsive cellular immune responses. Results: Both recombinant MVA constructs showed detectable E2 expression when E1 and E2 were co-expressed, and exhibited growth characteristics comparable to parental MVA with stable maintenance after serial passage. In contrast, recombinant MVA expressing E2 alone did not yield detectable E2 protein under the same experimental conditions. Immunization induced detectable humoral and cellular immune responses, including E2-specific IgG antibodies, virus-neutralizing antibodies, and increased frequencies of antigen-responsive CD8⁺ T cells with a tendency toward a Th1-biased profile. Conclusions: These findings indicate that co-expression of BVDV E1 and E2 in an MVA vector can support detectable antigen expression and induce measurable immune responses in a mouse proof-of-concept model. Further studies in cattle, including challenge experiments, will be required to determine the protective efficacy and practical applicability of this platform for BVDV vaccine development. Full article

The development of novel antiviral nanomaterials is an important approach for addressing emerging viral threats. In this study, glycyrrhizic acid-modified gold nanoparticles (GA-Au NPs) were successfully synthesized and characterized, and their inhibitory effects against porcine reproductive and respiratory syndrome virus (PRRSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudovirus were systematically evaluated. At non-cytotoxic concentrations, GA-Au NPs showed inhibitory activity against PRRSV in vitro. Stage-specific assays suggested that intracellular replication-related events were prominently affected, with additional inhibitory effects observed during adsorption, invasion, and release, whereas no direct virucidal activity was detected under the tested conditions. Furthermore, GA-Au NPs dose-dependently reduced SARS-CoV-2 pseudovirus infection-associated reporter signals in HEK-293T-ACE2 cells, supporting inhibitory activity in an additional viral model. In conclusion, GA-Au NPs represent a biocompatible antiviral nanomaterial with multi-stage inhibitory activity against PRRSV and inhibitory effects in a SARS-CoV-2 pseudovirus model, supporting their further evaluation as antiviral nanomaterials in enveloped virus-related models. Full article

LL-37, a 37-amino acid human-derived antimicrobial peptide, was shown in our earlier clinical study to shorten the negative conversion time of the Omicron BA.5.1.3 variant of SARS-CoV-2. In this work, we investigated the broad mechanism of LL-37 by examining its inhibitory effect on non-enveloped virus Enterovirus 71 (EV71). LL-37 treatment dose-dependently reduced EV71 viral RNA abundance, suppressed virus-encoded protein expression, and decreased infectious titers, acting predominantly at a post-entry stage of the viral life cycle. Transcriptomic analysis revealed that the SH3 and cysteine-rich domain protein (Stac) was uniquely upregulated by LL-37 irrespective of EV71 infection. Short hairpin RNA (shRNA)-mediated Stac silencing significantly enhanced EV71 infection, while Stac overexpression markedly reduced it. Furthermore, we found that LL-37 activates the EGFR–ERK signaling pathway, leading to time-dependent upregulation of Stac expression. These findings uncover a novel host-directed mechanism by which LL-37 combats EV71 infection and suggests a potential therapeutic use of LL-37 against non-enveloped viral disease. Full article

Chikungunya virus (CHIKungunya Virus, CHIKV) is a mosquito-borne plus-stranded RNA virus. Adaptive mutations such as A226V in the E1 envelope protein of CHIKV significantly enhance the transmission efficiency of the virus in Aedes albostriae, leading to multiple rounds of epidemics around the world including the large-scale outbreak in Guangdong Province in 2025. After a viral infection, a significant proportion of patients will progress from acute arthralgia to chronic arthritis that persists. The pathogenesis of the disease involves the persistence of the virus in joint tissues, the persistent inflammatory response with IL-1β, IL-6 and IL-17 as the core mediated by macrophages, possible autoimmune cross-reactions, and individual genetic susceptibility. At present, there is no specific antiviral drug, but important progress has been made in vaccine development against the virus. Vaccines based on live attenuated virus (VLA1553) and virus-like particle (VLP) platforms have been approved for the market and provide a tool to prevent and control this important public health threat. This review synthesizes current knowledge on CHIKV-induced chronic arthritis pathogenesis and recent vaccine advances, providing a framework for understanding disease mechanisms and guiding future prevention strategies. Full article

Human respiratory syncytial virus (RSV) is the predominant etiological agent responsible for lower respiratory tract infections in young children. Recurrent infections throughout an individual’s lifespan can lead to significant morbidity, particularly in the elderly and in adults, influencing the trends of hospitalization rates. Consequently, it is imperative to develop technologies that can sanitize environments from this pathogen while being compatible with human presence. Structure Resonant Energy Transfer (SRET) is the scientific principle underlying a sanitization technology that has demonstrated efficacy against several enveloped viruses, including SARS-CoV-2 and Influenza A viruses. SRET employs specific frequencies of electromagnetic waves to effectively disrupt the structural integrity of viral envelopes through dipole coupling. This disruption leads to the inactivation of the virus, rendering it non-infectious. The objective of this study is to analyse the effect of a specific SRET sanitization method on RSV. The sanitization test was conducted in aerosol form within a BSL-3 laboratory, exploring the frequency band from 8 to 16 GHz. An optimal sub-band was identified, giving an inactivation efficiency up to 99.5%. In conclusion, it has been demonstrated that the microwave non-thermal sanitization method is effective against RSV. These results confirm its potential as a viable approach for environmental decontamination. Full article

Lassa virus (LASV), the causative agent of Lassa fever, must be handled under biosafety level 4 (BSL-4) conditions, requiring validated inactivation protocols to ensure laboratory and public safety. Although LASV is an enveloped virus theoretically susceptible to physical and chemical inactivation methods, quantitative data on its inactivation kinetics remain limited. This study systematically evaluated the efficacy of thermal treatment (56 °C, 70 °C, 95 °C), laboratory chemical inactivants (beta-propiolactone, formaldehyde, methanol, TRIzol), and five commercial disinfectants against infectious LASV. Viral infectivity was determined by titrating residual virus in Vero E6 cells, and complete inactivation was verified by three consecutive blind passages. Thermal inactivation was achieved at 56 °C for 40 min, 70 °C for 5 min, and 95 °C for 2 min. Both 0.1% and 0.05% beta-propiolactone completely inactivated LASV after 24 h at 4 °C, while 4% formaldehyde, 50% methanol, and 25% TRIzol achieved complete inactivation within 15 min, 10 min, and 2 min, respectively. For surface disinfection, 2% and 5% Micro-Chem Plus™ and 75% ethanol reduced viral titers by ≥4 log₁₀ TCID₅₀/mL within 30 s; 1% sodium hypochlorite and 0.25% Virkon required 1 min, whereas 3% hydrogen peroxide required 3 min to achieve the same reduction. These results provide quantitative, evidence-based parameters that can serve as a valuable reference for the safe handling of LASV under controlled BSL-4 laboratory conditions. Full article

Background: Dengue virus (DENV) does not have any effective antiviral therapy. The Cinnamomum verum has cinnamic acid and oleic acid that could inhibit important viral proteins. Aim: To compare their inhibitory capacity with the key DENV proteins through molecular docking, molecular dynamics and in silico ADMET. Methods: Phytochemical profiling of the ethanolic extract of the bark was done by GCMS. AutoDock Vina (version 1.2.0) was used to dock cinnamic acid and oleic acid to key proteins of DENV (NS5, NS3, and envelope) in the presence of ribavirin as the reference. The best complexes were then subjected to 50 ns of molecular dynamics simulation and stability measured by RMSD, RMSF, Rg, SASA, hydrogen bonding and RDF. Validated in silico tools were used to predict the ADMET properties. Results: Analysis of GC–MS revealed cinnamic acid (85.92%) and oleic acid (5.33%). The outcome of docking was that the cinnamic acid had the greatest affinity with NS5 (−5.970 kcal/mol) and the capsid protein (−5.755 kcal/mol), and oleic acid showed the highest affinity with the capsid (−6.150 kcal/mol) and then with NS5 (−5.209 kcal/mol). Both ligands had a relatively weak interaction with NS3. Simulation of the molecular dynamics showed the stability of the top complexes, especially the cinnamic acid–NS5 complex, that retained low RMSD (1.6–1.9 A), stable Rg and SASA profiles, and continued hydrogen bonding during the 50 ns period. The use of cinnamic acid in ADMET projections was more preferable, as it was more soluble, orally bioavailable (0.91), and drug-like (QED 0.65), but oleic acid revealed higher lipophilicity and lower drug-like properties (QED 0.29). Conclusions: Cinnamic acid showed specificity towards the NS5 proteins with the help of stable dynamics and good predicted pharmacokinetics, which are features that make it a promising multi-target anti-DENV scaffold. Oleic acid exhibited poor affinity and poor pharmacokinetic properties. The findings are predictive and must be validated using biochemical, cellular, and toxicological means to prove the antiviral efficacy and safety. Full article

Human T-cell leukemia virus type-1 (HTLV-1) is endemic to numerous regions worldwide, including Central Australia. The Australo-Melanesian subtype-C is endemic within Australia and Oceania, whereas subtype-A is the most widely distributed subtype globally. The lack of an approved vaccine highlights HTLV-1 as a neglected public health issue. To inform the development of HTLV-1 Envelope (Env)-based vaccines, we assessed anti-Env antibodies in an HTLV-1c+ cohort of First Nations individuals in Central Australia. Of the 62 plasma samples from patients with confirmed HTLV-1 serological diagnosis, 76% were positive for Env binding in ELISA, but 90% neutralized HTLV-1c pseudovirus (PSV) infection. Neutralization breadth with the capability of blocking both subtype-A and subtype-C PSV infection was identified in 100% of samples tested. Proviral load was positively associated with anti-Env response, with binding epitopes mapping to the proline-rich region of gp46-SU. Env-directed IgG showed the capacity to engage Fcγ receptors key to inducing antibody-dependent cellular cytotoxicity/phagocytosis responses. Serological response was not associated with comorbidities linked to HTLV-1c in this population (bronchiectasis, chronic kidney disease, diabetes). These findings demonstrate that potent humoral immunity arises and is sustained during HTLV-1 infection, suggesting that an Env-based vaccine displaying authentically native epitopes will be capable of recapitulating these neutralizing responses. Full article

Porcine reproductive and respiratory syndrome (PRRS) remains one of the most economically devastating diseases in global swine production. The causative agent, PRRS virus (PRRSV), comprises two genetically distinct species—PRRSV-1 and PRRSV-2—that differ substantially in antigenic composition and immune recognition. Despite widespread use of modified live vaccines (MLVs), protection against heterologous and cross-species strains remains inconsistent and difficult to predict. This review synthesizes current knowledge of homologous, heterologous, and cross-species protection, with emphasis on humoral and cellular immune responses and the viral determinants that constrain breadth of immunity. Neutralizing antibodies can confer near-sterilizing homologous protection under controlled conditions; however, their delayed induction and narrow specificity limit efficacy against heterologous strains. T-cell-mediated responses are generally broader but remain highly strain- and context-dependent. Structural features of PRRSV envelope glycoproteins, including glycan shielding and immunodominant decoy epitopes, further restrict antibody-mediated cross-protection while providing targets for rational vaccine design. We also examine potential drawbacks of preexisting immunity, including antigenic mismatch and non-neutralizing antibody-dominated responses that may contribute to suboptimal outcomes following heterologous exposure. Collectively, these findings highlight the multifactorial nature of PRRSV protection and the need for next-generation vaccines capable of inducing broader and more durable immunity. Full article

Background/Objectives: Chimpanzee adenoviral-vectored vaccines have proven to be both safe and effective, with a manufacturing and distribution pipeline capable of rapid global supply, as demonstrated during the COVID-19 pandemic. Yellow fever is a mosquito-borne viral hemorrhagic disease endemic in parts of Africa and Latin America, and although an effective live attenuated vaccine exists, its use is limited by safety and eligibility restrictions. Moreover, large outbreaks continue to expose critical challenges, such as an insufficient vaccine supply, reliance on fractional dosing, and slow and difficult-to-scale manufacturing processes. Here, we report the design, development and in vivo immunogenicity of multiple yellow fever virus (YFV) antigen constructs based on the pre-membrane (prM) and envelope (E) proteins—with or without the transmembrane domain (TM or ΔTM)—delivered using the ChAdOx1 adenoviral vector. Methods: Four ChAdOx1 YF vaccines were developed, and immunogenicity was evaluated. The efficacy of the full-length YF envelope vaccine was also tested in Balb/c mice. Results/Conclusions: In contrast to previously described orthoflavivirus vaccines on the same platform, the full-length antigen elicited superior immunogenicity and conferred protection against intracranial challenge with the YF17D virus in mice. Notably, this protection was comparable to that induced by the licensed YF17D vaccine, highlighting the promise of this platform as a next-generation yellow fever vaccine candidate. Full article

Polysaccharides derived from cyanobacteria and microalgae have attracted increasing interest as natural virucidal agents. Among them, polysaccharides from the cyanobacterium Arthrospira platensis (A. platensis), and the green microalgae Dunaliella salina (D. salina) have shown virucidal activities, mainly against enveloped viruses, while evidence on non-enveloped viruses is still limited. In this study, the virucidal activity of purified polysaccharides extracted from A. platensis (APPs) and from D. salina (DSPs) was evaluated in vitro against human adenovirus type 5 (HAdV5), a non-enveloped pathogenic virus with high persistence in the environment and resistance to disinfection. The in vitro assays were carried out at concentrations previously verified as non-toxic by morphological evaluation of A549 cells after 24 and 48 h of incubation, testing two viral loads, namely, 10³ and 10⁴ tissue culture infectious dose 50% per milliliter (TCID₅₀/mL). For APPs, a possible time-dependent effect was also assessed at different contact times (15, 30 and 60 min). DSPs showed a limited virucidal effect related to the starting viral concentration, while APPs induced a consistent viral reduction (up to 98.8%) at both viral concentrations. The virucidal effect of APPs occurred rapidly and was not significantly influenced by contact time, thus suggesting that prolonged exposure is not a determining factor for polysaccharide virucidal activity. These findings demonstrate the virucidal activity of APPs against a highly resistant non-enveloped virus and provide preliminary in vitro evidence of their potential application as natural virucidal agents, particularly for environmental disinfection purposes. Further investigations are warranted to elucidate the underlying mechanisms of action and to optimize their practical use. Full article

JC Polyomavirus (JCPyV) is a non-enveloped virus with circular double stranded DNA responsible for the rare but fatal demyelinating disease known as progressive multifocal leukoencephalopathy (PML). In its host, this virus exists in two different forms: one found in the periphery, named archetype, and another found in the central nervous system, named prototype. This form usually harbors recombinations in the non-coding control region (NCCR), a key region that contains sequences regulating viral replication and containing binding sites for cellular transcription factors. This form also contains mutations in the capsid protein, especially VP1. Due to the diversity of the JCPyV, a natural polymorphism also exists between the different genotypes. In this review, we aimed to summarize the main features of the archetype and prototype strains in order to facilitate the interpretation of sequence data that are increasingly generated by new sequencing technologies. This will also help to distinguish mutations associated with the natural polymorphism from those specific to the prototype form. Full article

Caprine herpesvirus 1 (CpHV-1) is responsible for significant economic losses in goat farming. The CpHV-1 genital infection in goats has been used as a homologous animal model for the study of human herpes simplex virus type 2 (HSV-2). This study aimed to investigate the in vitro virucidal and antiviral effect of lemon juice (LJ) and its main component, citric acid (CA), against CpHV-1 on Madin-Darby Bovine Kidney (MDBK) cells. Cytotoxicity was assessed using an XTT assay, while viral titers were determined by the Reed–Muench method and viral DNA was quantified via qPCR. Pure LJ (pH 2.3) and its corresponding CA solution demonstrated potent and rapid virucidal activity, reducing the viral titer by over 5.0 log10 TCID₅₀/50 µL within 1 min. When applied after viral entry, a non-cytotoxic dilution of LJ (pH 4.32) significantly inhibited viral replication, causing a 2.5 log10 TCID₅₀/50 µL reduction in viral titer and a corresponding decrease in viral DNA. The antiviral effects were minimal at a near-neutral pH of 6.67, probably interacting with envelope structures. These results suggest that LJ could be a potential low-cost topical agent or disinfectant for controlling CpHV-1 in goat populations and offer a basis for translational research on human herpesviruses. Full article