Search Results (114)

Dengue virus (DENV) poses a major global health concern, with over 6.5 million cases and 7300 deaths reported in 2023. Accurate serological assays are essential for tracking infection history, evaluating disease severity, and guiding vaccination strategies. However, existing assays are limited in their specificity, sensitivity, and cross-reactivity. Using optical modulation biosensing (OMB) technology and non-structural protein 1 (NS1) antigens from DENV-1–3, we developed highly sensitive and quantitative serotype-specific anti-DENV NS1 IgG serological assays. The OMB-based assays offered a wide dynamic range (~4-log), low detection limits (~400 ng/L), fast turnaround (1.5 h), and a simplified workflow. Using samples from endemic (Vietnam) and non-endemic (Israel) regions, we assessed intra-DENV and inter-Flavivirus cross-reactivity. Each assay detected DENV infection with a 100% sensitivity for the corresponding serotype and 64% to 90% for other serotypes. Cross-reactivity with Zika, Japanese encephalitis, and West Nile viruses ranged from 21% to 65%, reflecting NS1 antigen conservation. Our study provides valuable insights into the cross-reactivity of DENV NS1 antigens widely used in research and highlights the potential of OMB-based assays for quantitative and epidemiological studies. Ongoing efforts should aim to minimize cross-reactivity while maintaining sensitivity and explore integration with complementary platforms for improved diagnostic precision. Full article

Background: The evaluation of antiviral or vaccination strategies for the prevention of dengue infections in a traveler population would require extensive and complex studies. This prospective study aimed to identify a cohort of dengue naïve participants living in Medellín, a dengue endemic area, as a proxy for travelers and to determine the incidence of primary dengue virus (DENV) infection (symptomatic and asymptomatic) in this cohort. In Colombia, epidemic dengue waves occur every 3–4 years, with infected Aedes mosquitoes present in ~80% of the territory, including Medellín. Methods: Participants > 16 years of age, living in Medellín, were screened for anti-DENV immunoglobulin G (IgG). DENV seronegative participants were enrolled in this study. A serological anti-DENV survey was performed, with semiannual sample collections for up to 2 years. Acute DENV infections were evaluated by monitoring fever and testing for DENV nonstructural protein 1 and/or RNA. Results: Of the 4885 screened participants, 3008 participants (62%) were DENV seronegative and enrolled. Among them, 2263 (75%) completed this study, and 2644 (88%) had at least one serosurvey visit after baseline. Of those, 52 (2%) had laboratory-confirmed DENV seroconversion, and 19 (<1%) had febrile illness, but none had laboratory-confirmed DENV infection. Conclusions: This study identified a cohort of predominantly students, seronegative at study start, living in Medellín and serving as a proxy for a prospective DENV infection traveler population. Laboratory-confirmed primary DENV infection was found in 2% of participants, with <1% reporting febrile illnesses, meeting the WHO criteria for probable clinical dengue cases. Full article

Dengue virus (DENV) infection is strongly associated with dengue hemorrhagic fever and dengue shock syndrome, both of which carry mortality risks. Addressing the urgent need for effective dengue therapeutics, we identified sofalcone, a gastroprotective agent with antioxidant and anti-inflammatory properties, as a potential inhibitor of DENV replication. Sofalcone demonstrated efficacy against all four DENV serotypes, with the dose inhibiting 50% (IC50) value of 28.1 ± 0.42 μM against viral replication of DENV serotype 2, without significant cytotoxicity. Additionally, sofalcone significantly improved survival rates and reduced viral titers in DENV-infected ICR-suckling mice. Mechanistically, sofalcone induced heme oxygenase-1 (HO-1) expression via the nuclear factor-erythroid 2-reated factor 2 (Nrf2) pathway, which in turn suppressed viral protease activity and restored antiviral interferon (IFN) responses. This included dose-dependent stimulation of IFN downstream antiviral genes such as 2′-5′-oligoadenylate synthetase 1 (OAS1), OAS2, and OAS3. Given its established clinical use as an anti-gastric ulcer drug, sofalcone offers promising potential for rapid application in treating DENV infection. Full article

Background: Dengue is a global health concern, with half of the world’s population at risk and no antiviral treatment available. This Phase 0 study investigated dengue infections among household contacts (HHCs) of dengue index cases (ICs) and assessed the feasibility of conducting a Phase 2 trial for a novel antiviral. Methods: Participants were enrolled in Nha Trang, Vietnam, from April 2022 to February 2023. Dengue ICs were identified within 72 h of fever onset, and their healthy adult HHCs enrolled within 48 h. Blood samples and questionnaires were collected bi-weekly for four weeks, with a follow-up visit on day 40. DENV RT-qPCR, NS1, and anti-DENV IgM/IgG ELISAs were performed. Results: Overall, 130 dengue ICs and 301 HHCs were enrolled, with 91.7% (276/301) completing all follow-up visits. Baseline anti-DENV IgG showed prior dengue infections in 262/301 HHCs (87.0%). Fifty HHCs were excluded from the HHC infection analysis based on evidence of a DENV infection (viral load [VL], NS1, IgM, and IgG results) at enrollment. During follow-up, 2.0% of HHCs (5/251) had DENV infections based on virological parameters (DENV RNA and/or NS1 positivity), and anti-DENV IgG/IgM seroconversion was detected in 7.2% (18/251). Conclusions: This study demonstrated the operational feasibility of a dengue IC-HHC design for a Phase 2 trial. Full article

The DENV virus circulates freely in endemic regions and causes dengue disease. The vectors are Aedes aegypti and Aedes albopictus. The difficulties inherent in the nature of the DENV virus, its epidemiology, and its increasing incidence in recent years have led to the development of viable alternatives in the search for effective solutions for the treatment of this severe disease. Flavones such as tropoflavin, baicalein, and luteolin have anti-DENV activity. Molecular docking studies were performed between the flavones tropoflavin, baicalein, and luteolin and the DENV E-3 protein. Flavone—DENV E-3 complex interactions were analyzed at the flavonoid binding sites domain I of the B chain and domain II of the A chain reported in the literature. H-bond, π-π stacking, and π-cation interactions between flavones and the DENV E-3 protein at different binding energies were evaluated. Molecular dynamics studies for these interactions were performed to determine the molecular stability of the Flavone—DENV E-3 complexes. I also present here the results of the molecular interactions of the Flavone—DENV E-3―SWCNT complex. Due to recent advances in nanotechnology and their physicochemical properties, the utilization of nanoparticles such as SWCNT has increased in antiviral drug delivery. Full article

Background. Flaviviruses spread from endemic to non-endemic areas, causing illness in millions of people worldwide. The lack of effective therapies and the rapid expansion of flaviviral infections worldwide emphasize the importance of finding effective antivirals to treat such diseases. Objectives. To find out the potential broad-spectrum flavivirus inhibitors among previously reported inhibitors of DENV2/DENV4. Methods. The cytotoxicity of compounds was tested using WST-1 assay. The compounds were tested for their ability to inhibit the infection of DENV2, ZIKV, KUNV, and TBEV, and the most active compounds were also analyzed using the replicon-based assay. Interactions of one of the identified inhibitors with possible viral targets were studied using molecular dynamics simulations. Results. Two out of eight previously reported DENV2/DENV4 inhibitors demonstrated the ability to inhibit all studied viruses at low micromolar concentrations. Compound C6 demonstrated the ability to inhibit both DENV2 and TBEV. Compounds C1 (lycorine), C3 (mycophenolic acid), and C7 (vidarabine) were demonstrated as inhibitors of TBEV infection for the first time. Conclusions. Several compounds, previously described as inhibitors of DENV, are also able to inhibit other flaviviruses. This work is the first report on the anti-TBEV activity of lycorine (C1) and mycophenolic acid (C3), as well as vidarabine (C7). In addition, this is the first experimental confirmation of the antiviral activity of compound C5 and the lack of detectable antiviral activity of compound C8, demonstrating the necessity of experimental verification of the computational predictions. Full article

This study aimed to assess the diagnostic utility of VIDAS^® DENGUE NS1 Ag and anti-DENV IgM and IgG assays in parallel for an early and accurate diagnosis and classification of dengue virus (DENV) infection. For this retrospective cross-sectional study, 190 patients with suspected dengue were tested using VIDAS^® NS1, IgM, and IgG assays, requested in parallel, regardless of symptom onset timing, and classified into primary and secondary infections. Results were analyzed to determine diagnostic accuracy and correlation with disease severity. Parallel testing effectively differentiated between primary and secondary DENV infection. Secondary dengue cases with warning signs showed significantly elevated IgG levels (p = 0.026). Notably, NS1-negative (possible secondary cases) had higher IgM and IgG levels than NS1-positive cases (p < 0.01), suggesting that NS1 negativity might indicate an amplified immune response. In conclusion, VIDAS^® Dengue diagnostic assays not only enhance the diagnostic accuracy of dengue infection but also offer valuable insights into serological patterns, especially in secondary cases. These assays could be used not only to confirm diagnosis but also to stratify patients by risk, particularly in cases of secondary dengue, where IgG levels might indicate a higher risk for severe outcomes. Full article

Chikungunya virus (CHIKV) is classified as a pathogen with the potential to cause a pandemic. This situation becomes more alarming since no approved drug exists to combat the virus. The present research aims to demonstrate the anti-CHIKV activity of molecules present in the latex of Euphorbia grandicornis. Therefore, a biodirected assay was carried out to find the molecules with anti-CHIKV activity. Extractions with hexane, dichloromethane, and methanol and subsequent purification by column chromatography were carried out to later evaluate cytotoxic activity by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and antiviral activity by plaque assay. Our findings show that unlike the others, methanolic extract has a low cytotoxic effect and a good anti-CHIKV effect (EC₅₀ = 26.41 µg/mL), which increases when obtaining the purified active fraction (pAFeg1) (EC₅₀ = 0.4835 µg/mL). Time-of-addition suggests that the possible mechanism of action of pAFeg1 could be inhibiting any of the non-structural proteins of CHIKV. In addition, both the cytotoxic and anti-CHIKV activity of pAFeg1 demonstrate selectivity since it killed cancer cells and could not inhibit DENV2. Full article

Dengue virus (DENV) is transmitted by Aedes genus mosquitoes and is responsible for dengue fever (DF) and other severe diseases, posing a significant challenge to the global health system. Currently, anti-dengue pharmacological treatment options are not available. Earlier, we demonstrated that Sinococuline has potent anti-dengue activity and prevents virus infection. In this study, we profile the host transcriptome response in the Vero cells after infection with DENV2 in the presence of Sinococuline, using bioinformatics to identify significant differentially expressed genes (DEGs). A total of 1510 DEGs were noted by transcriptional analysis of Vero cells that were infected with dengue virus as compared to the uninfected cells, among which 697 were upregulated and 813 were downregulated. Also, 184 out of 697 and 254 out of 817 genes were altered in dengue-infected Vero cells in the presence of Sinococuline. We found that TNF, cytokine–cytokine receptor interactions, and NF-kB signaling pathways were differentially expressed in DENV2-infected Vero cells, which was prevented by Sinococuline. The findings of this study add to our knowledge of Sinococuline’s antiviral activity in DENV2-infected Vero cells at the transcriptome level. These findings also identify potential candidate antiviral genes that can be verified for their function in the future. Full article

This study investigates the kinetics of interleukine-6 (IL-6) and interleukine-10 (IL-10) levels in dengue virus (DENV) infections during the febrile stage. Viremic patients were categorized into two phases based on anti-DENV IgM presence. Among 259 patients, 71% were in Phase I and 29% in Phase II. Secondary infections, accounting for 38.2% of cases, exhibited earlier elevations of IL-6 and IL-10 than primary infections, suggesting that pre-existing immune memory primes faster cytokine release. Thrombocytopenia and elevated aspartate transaminase (AST) levels were associated with Phase II, secondary infections, and hospitalization. Elevated IL-6 and IL-10 levels correlated with low platelet counts, linking them to clinical manifestations. The key finding is that IL-6 and IL-10 levels rise earlier in secondary infections compared to primary infections, whereas elevated cytokine levels typically occur later in the febrile phase. This study highlights the importance of cytokine dynamics in DENV infections, particularly during the early stages. The observation of cytokine concentration changes, especially in viremic samples, provides insights into the progression of dengue disease. Further research with broader cytokine panels is warranted to validate and expand these findings. Full article

Dengue is an emerging disease of high impact on human health. Plants are an important source of new antivirals and Arachis hypogaea stands for its biological properties. The aim of this study was to evaluate the cytotoxicity and antiviral activity and elucidate the antiviral mechanism of ethanolic extracts from A. hypogaea against dengue virus 2 (DENV-2). The skin or tegument ethanolic extract (TEEs) and seed ethanolic extract (SEEs) were obtained. Cytotoxicity was evaluated by MTT and Neutral Red Uptake (NRU). Antiviral activity was evaluated at different stages of the viral replication cycle by the lysis plaque reduction method. The 50% inhibitory concentration (IC₅₀) and selectivity index (SI) were determined. Antiviral activity was further determined by RT-qPCR. The CC₅₀ values were 169 (NRU) and 65 (MTT) µg/mL for TEE. In addition, the CC₅₀ values were >1400 (NRU) and 636 (MTT) µg/mL for SEE. The TEE demonstrated 99.9 ± 0.1% viral inhibition. The TEE presented an IC₅₀ = 3.47 and SI of 48.7 (NRU) and 18.73 (MTT). Its mechanism of antiviral action is broad and it acts in the viral adsorption–penetration stage and inhibits the first steps of infection in the post-penetration stage. It is also capable of acting as virucidal and as prophylactic. Studies of RT-qPCR indicated that the TEE inhibited viral RNA synthesis. These findings suggest that the TEE from A. hypogaea could be a promising antiviral candidate for treating DENV-2 infections. Full article

Dengue virus (DENV) infection, prevalent in tropical and subtropical regions, can progress to dengue hemorrhagic fever (DHF), which increases mortality during secondary infections. DHF is characterized by endothelial damage and vascular leakage. Despite its severity, no specific antiviral treatments exist, and the viral factors responsible for endothelial damage remain unclear. This study examines the role of the DENV envelope protein domain III (EIII) in inducing endothelial apoptosis using a mouse model. Additionally, we aim to explore whether cell death-inducing pathways could serve as drug targets to ameliorate EIII-induced endothelial injury and hemorrhage. In vitro experiments using human endothelial HMEC-1 cells demonstrated that both recombinant EIII (rEIII) and DENV markedly induced caspase-3-mediated endothelial cell death, an effect that was attenuated by co-treatment with chondroitin sulfate B (CSB), N-acetyl cysteine (NAC), and the caspase-3 inhibitor z-DEVD-FMK. In vivo, sequential injections of rEIII and anti-platelet immunoglobulin in mice, designed to mimic the clinical phase of DHF with peak viremia followed by an increase in DENV-induced Ig, including autoantibodies, revealed that these dual treatments markedly triggered caspase-3-dependent apoptosis in vascular endothelial cells at hemorrhage sites. Treatments with z-DEVD-FMK effectively reduced DHF-like symptoms such as thrombocytopenia, hemorrhage, inflammation, hypercoagulation, and endothelial damage. Additionally, CSB and NAC alleviated hemorrhagic symptoms in the mice. These results suggest that targeting EIII, reactive oxygen species, and caspase-3-mediated apoptosis could offer potential therapeutic strategies for addressing EIII-induced hemorrhagic pathogenesis. Full article

Oropouche Virus (OROV; genus of Orthobunyavirus) is the causal agent of Oropouche Fever (OF). Due to the lack of specific signs and symptoms and the limited availability of diagnostic tests, the actual epidemiology of OROV infections and OF has been extensively disputed. In this systematic review with meta-analysis, a literature search was carried out in PubMed, Scopus, EMBASE, and MedRxiv in order to retrieve relevant articles on the documented occurrence of OROV infections. Pooled detection rates were then calculated for anti-OROV antibodies and virus detection (i.e., viral RNA detected by viral cultures and/or real-time polymerase chain reaction [RT-qPCR]). Where available, detection rates for other arboviruses (i.e., Dengue [DENV], Chikungunya [CHKV], and Zika Virus [ZIKV]) were calculated and compared to those for OROV. A total of 47 studies from South America and the Caribbean were retrieved. In individuals affected by febrile illness during OROV outbreaks, a documented prevalence of 0.45% (95% confidence interval [95%CI] 0.16 to 1.12) for virus isolation, 12.21% (95%CI 4.96 to 27.09) for seroprevalence (including both IgM and IgG class antibodies), and 12.45% (95%CI 3.28 to 37.39) for the detection of OROV-targeting IgM class antibodies were eventually documented. In the general population, seroprevalence was estimated to be 24.45% (95%CI 7.83 to 55.21) for IgG class antibodies. The OROV detection rate from the cerebrospinal fluids of suspected cases of viral encephalitis was estimated to be 2.40% (95%CI 1.17 to 5.03). The occurrence of OROV infections was consistently lower than that of DENV, CHKV, and ZIKV during outbreaks (Risk Ratio [RR] 24.82, 95%CI 21.12 to 29.16; RR 2.207, 95%CI 1.427 to 3.412; and RR 7.900, 95%CI 5.386 to 11.578, respectively) and in the general population (RR 23.614, 95%CI 20.584 to 27.129; RR 3.103, 95%CI 2.056 to 4.685; and RR 49.500, 95%CI 12.256 to 199.921, respectively). In conclusion, our study stresses the possibly high underestimation of OROV prevalence in the general population of South America, the potential global threat represented by this arbovirus infection, and the potential preventive role of a comprehensive “One Health approach”. Full article

Dengue virus (DENV) infection has emerged as a global health problem, with no specific treatment available presently. Clinacanthus nutans (Burm. f.) Lindau extract has been used in traditional medicine for its anti-inflammatory and antiviral properties. We thus hypothesized C. nutans had a broad-ranged activity to inhibit DENV and the liver inflammation caused by DENV infection. The study showed that treatment using C. nutans extract during DENV infection (co-infection step) showed the highest efficiency in lowering the viral antigen concentration to 22.87 ± 6.49% at 31.25 μg/mL. In addition, the virus–host cell binding assay demonstrated that C. nutans treatment greatly inhibited the virus after its binding to Huh7 cells. Moreover, it could remarkably lower the expression of cytokine and chemokine genes, including TNF-α, CXCL10, IL-6, and IL-8, in addition to inflammatory mediator COX-2 genes. Interestingly, the activation of the NF-κB signaling cascade after C. nutans extract treatment was dramatically decreased, which could be the underlying mechanism of its anti-inflammatory activity. The HPLC profile showed that gallic acid was the bioactive compound of C. nutans extract and might be responsible for the antiviral properties of C. nutans. Taken together, our results revealed the potential of C. nutans extract to inhibit DENV infection and lower inflammation in infected cells. Full article

Despite successful vaccination efforts, the emergence of new SARS-CoV-2 variants poses ongoing challenges to control COVID-19. Understanding humoral responses regarding SARS-CoV-2 infections and their impact is crucial for developing future vaccines that are effective worldwide. Here, we identified 41 immunodominant linear B-cell epitopes in its spike glycoprotein with an SPOT synthesis peptide array probed with a pool of serum from hospitalized COVID-19 patients. The bioinformatics showed a restricted set of epitopes unique to SARS-CoV-2 compared to other coronavirus family members. Potential crosstalk was also detected with Dengue virus (DENV), which was confirmed by screening individuals infected with DENV before the COVID-19 pandemic in a commercial ELISA for anti-SARS-CoV-2 antibodies. A high-resolution evaluation of antibody reactivity against peptides representing epitopes in the spike protein identified ten sequences in the NTD, RBD, and S2 domains. Functionally, antibody-dependent enhancement (ADE) in SARS-CoV-2 infections of monocytes was observed in vitro with pre-pandemic Dengue-positive sera. A significant increase in viral load was measured compared to that of the controls, with no detectable neutralization or considerable cell death, suggesting its role in viral entry. Cross-reactivity against peptides from spike proteins was observed for the pre-pandemic sera. This study highlights the importance of identifying specific epitopes generated during the humoral response to a pathogenic infection to understand the potential interplay of previous and future infections on diseases and their impact on vaccinations and immunodiagnostics. Full article