Search Results (572)

Background and Clinical Significance: Malaria remains a significant public health issue in Latin America, where Plasmodium vivax predominates but P. falciparum continues to circulate. Mixed-species infections are uncommon and can pose diagnostic challenges, particularly when parasite densities differ markedly, increasing the risk of underdetecting P. falciparum with conventional methods. Case report: We report a 9-year-old boy from an endemic area with a six-day febrile syndrome. Thick smear and peripheral blood film microscopy, complemented by rapid diagnostic tests for pan-Plasmodium and HRP2 antigens, confirmed a mixed infection with P. vivax (5500 parasites/µL) and P. falciparum (562 parasites/µL). The patient was hemodynamically stable, without severe malaria criteria, and laboratory values were within normal limits. Following confirmation of normal glucose-6-phosphate dehydrogenase activity, treatment with artemether–lumefantrine was initiated, followed by primaquine for hypnozoite eradication. Clinical evolution was favorable, with progressive defervescence, treatment tolerance, and documented parasite clearance. Conclusions: This case illustrates the risk of underestimating P. falciparum in mixed infections with disparate parasitemias and highlights the value of integrated diagnostic approaches in resource-limited endemic settings. It also underscores surveillance limitations that can misclassify mixed infections, potentially affecting epidemiological estimates and treatment strategies. Timely recognition and comprehensive diagnostic evaluation are essential to ensure appropriate antimalarial therapy, prevent complications, and inform public health interventions in regions where both species coexist. Full article

Background: Children and adolescents are pivotal in the transmission of influenza, and vaccination remains the most effective preventive measure. Cell-based influenza vaccines offer advantages over traditional egg-based vaccines by reducing egg-adapted mutations and improving antigenic match. SKYCellflu^® quadrivalent influenza vaccine (QIV; SK bioscience, Korea), the first cell-based QIV licensed in Korea for individuals aged 6 months and older, offers potential advantages; however, its real-world effectiveness in the Korean pediatric population remains limited. Objective: This study aimed to estimate the real-world effectiveness of SKYCellflu^® QIV, a cell-based QIV, in preventing laboratory-confirmed influenza among children and adolescents aged 6 months to 18 years in Korea during the 2024–2025 influenza season. Methods: A multicenter, prospective, test-negative case–control study was conducted from October 2024 to May 2025 across 25 institutions in Korea. Children and adolescents aged 6 months to 18 years who presented within 7 days of the onset of influenza-like illness (fever ≥ 38 °C and at least one respiratory symptom) were enrolled. Influenza infection was confirmed using rapid antigen tests or polymerase chain reaction; participants who tested positive were classified as cases, and those who tested negative for influenza served as controls. All participants were further categorized as vaccinated or unvaccinated based on receipt of SKYCellflu^® QIV. Those who received other influenza vaccines during the season were excluded. Vaccination status was verified through medical records and the national immunization registry. Results: A total of 1476 participants were included (751 cases, 725 controls). The overall adjusted vaccine effectiveness (aVE) was 45.57% (95% CI, 29.38–58.04). The vaccine demonstrated the highest effectiveness in children aged 6–35 months (aVE: 88.55%; 95% CI, 60.39–96.11). Effectiveness was higher against influenza B (aVE: 61.28%; 95% CI, 35.76–76.30) than influenza A (aVE: 41.63%; 95% CI, 22.55–56.01). The vaccine’s effectiveness in adolescents was not statistically significant due to the small sample size in this age group. Conclusions: This multicenter test-negative study provides the first real-world effectiveness of SKYCellflu^® QIV in a Korean pediatric population. The results suggest substantial protection in younger children, particularly against influenza B, and support the continued use of annual influenza vaccination in this population. Further studies with larger adolescent cohorts are needed to confirm these findings in older age groups. Full article

This study aimed to identify and evaluate the risk factors associated with Giardia spp. infection among generally hospitalized patients with various conditions specific to infectious diseases in Western Romania. A total of 312 patients, ranging in age from 2 months to 90 years and originating from both urban and rural settings, were included in the analysis. Fecal specimens were collected and analyzed using the Rapid-VIDITEST Crypto Giardia antigen test, a qualitative chromatographic assay for the detection of Giardia spp. Infection-related risk factors were assessed through a standardized questionnaire completed by adult patients or by the guardians of pediatric patients. The overall prevalence of Giardia spp. infection was 4.8%. Of the risk factors analyzed, only age demonstrated a statistically significant association with infection status (p < 0.05). Notably, the highest prevalence (12.5%) was recorded in the <1-year age group (2–11 months), with a marked decrease in prevalence observed among patients aged ≥60 years. Other evaluated risk factors—including area of residence, gender, contact with animals, pet ownership, hand hygiene after animal contact, type of housing (house or apartment), fruit washing practices, use of potable water, use of public transportation, international travel, and visits to playgrounds or swimming pools—did not show a statistically significant association with Giardia spp. infection among the study participants. The lack of statistical significance for several expected factors may be related to limited statistical power resulting from the low number of positive cases. These findings contribute to the current understanding of Giardia spp. transmission dynamics and may inform future research efforts aimed at elucidating relevant risk factors. Furthermore, the results may support the development of targeted public health interventions (focusing on infants and their caregivers) and prevention strategies. Full article

This study describes an optimized plastic surface-based capsid protein adsorption/capturing method for detection of cowpea mild mottle virus (CPMMV) adapted from the direct antigen-capture method reported for the extraction of rose rosette virus (RRV) and other direct virus capturing attempts. Briefly, the method starts with sap incubation, removal of unbound residual tissue and inhibitors by washing, and the viral RNA release using nuclease-free water and heat, in the presence of an RNase inhibitor. The protocol’s efficiency was assessed across different pH conditions, RNaseOUT concentrations, and reverse-transcriptase choices, and its performance was compared with commercial RNA-extraction methods. Three hundred thirty-two positive samples for CPMMV were processed using the optimized protocol (PBS-T, pH 7.4; RNaseOUT at 0.5 U/µL; and M-MLV reverse transcriptase). RT-PCR detection results were consistent with those obtained using the standard method. Cost estimates for tissue trapping indicate reductions of approximately 70% and 90% compared with the Qiagen RNeasy kit (Qiagen, Hilden, Germany) and the Bertheau method, respectively. The tissue-absorption protocol combines simplicity and low cost, making it particularly well suited for field diagnostics; by enabling rapid recovery of viral RNA without commercial kits and substantially reducing processing steps, it represents a practical, cost-effective alternative for routine CPMMV testing. Full article

Background: Memory B cells (B_mem) facilitate the generation of renewed and rapid antigen-specific antibody responses long after the initial antigen exposure, at a time when circulating serum antibodies may have declined. As the generation and/or recruitment of B_mem is at the core of most vaccination strategies, the assessment of antigen-specific B_mem is highly informative for forecasting and profiling the elicited B cell immune response. Methods: The two prevalent techniques used to detect antigen-specific B_mem cells at single-cell resolution are probe-based flow cytometry and B cell ImmunoSpot, while the measurement of B cell-derived antibodies in culture supernatants of stimulated B cells offers a semi-quantitative alternative. To the best of our knowledge, a direct side-by-side comparison of these assay systems has not yet been reported using the same starting PBMC material in a blinded fashion to test all three assays simultaneously. Results: These three assay systems were run in parallel to detect SARS-CoV-2 Wuhan-1 strain Spike-specific IgG⁺ B_mem in peripheral blood mononuclear cell (PBMC) samples obtained from well-defined cohorts comprising pre-COVID-19 era “naïve” individuals (negative controls), individuals shortly after recovery from a PCR-verified SARS-CoV-2 infection (positive controls), and a cohort of donor PBMCs isolated in 2024 (the experimental group). Each assay was able to discern Spike-exposed individuals from naïve , with ImmunoSpot suggesting superior sensitivity and specificity. ImmunoSpot and flow cytometry results were closely correlated. Conclusions: The study demonstrates that all three assays are suited for the detection of specific B_mem in antigen-primed individuals when such B_mem occur in the mid- to high-frequency range, and that they broadly concur. Strengths and weaknesses of the three test systems are discussed. Full article

Background/Objectives: New vaccine platforms that rapidly yield low-cost, easily manufactured vaccines are highly desired, yet current approaches lack key features. We developed the Killed Whole-Cell/Genome-Reduced Bacteria (KWC/GRB) platform, which uses a genome-reduced Gram-negative chassis to enhance antigen exposure and modularity via an autotransporter (AT) system. Integrated within a Design–Build–Test–Learn (DBTL) framework, KWC/GRB enables rapid iteration of engineered antigens and immunomodulatory elements. Here, we applied this platform to the HIV-1 fusion peptide (FP) and tested multiple antigen engineering strategies to enhance its immunogenicity. Methods: For a new vaccine, we synthesized DNA encoding the antigen together with selected immunomodulators and cloned the constructs into a plasmid. The plasmids were transformed into genome-reduced bacteria (GRB), which were grown, induced for antigen expression, and then inactivated to produce the vaccines. We tested multiple strategies to enhance antigen immunogenicity, including multimeric HIV-1 fusion peptide (FP) designs separated by different linkers and constructs incorporating immunomodulators such as TLR agonists, mucosal-immunity-promoting peptides, and a non-cognate T-cell agonist. Vaccines were selected based on structure prediction and confirmed surface expression by flow cytometry. Mice were vaccinated, and anti-FP antibody responses were measured by ELISA. Results: ELISA responses increased nearly one order of magnitude across design rounds, with the top-performing construct showing an ~8-fold improvement over the initial 1mer vaccine. Multimeric antigens separated by an α-helical linker were the most immunogenic. The non-cognate T-cell agonist increased responses context-dependently. Flow cytometry showed that increased anti-FP-mAb binding to GRB was associated with greater induction of antibody responses. Although anti-FP immune responses were greatly increased, the sera did not neutralize HIV. Conclusions: Although none of the constructs elicited detectable neutralizing activity, the combination of uniformly low AlphaFold pLDDT scores and the functional data suggests that the FP region may not adopt a stable native-like structure in this display context. Importantly, the results demonstrate that the KWC/GRB platform can generate highly immunogenic vaccines, and when applied to antigens with well-defined native tertiary structures, the approach should enable rapidly produced, high-response, very low-cost vaccines. Full article

Acute myocardial infarction (AMI) is a rapidly progressing cardiovascular condition associated with high mortality. Myoglobin is an early biomarker of AMI; however, its detection using conventional methods is limited by complex workflows and low resistance to interference. In this study, we developed an integrated myoglobin detection platform that combined magneto-immunoassay with microfluidic technology. A giant magnetoresistance (GMR) sensor was fabricated using micro-electro-mechanical systems (MEMS). The designed microfluidic chip integrated sample pretreatment, immunoreaction, and magnetic signal capture functionalities. Its built-in GMR sensor, labeled with magnetic nanoparticles, directly converted the “antigen–antibody” biochemical signal into detectable magnetoresistance changes, thereby enabling the indirect detection of myoglobin. A magneto-immunoassay analysis system consisted of a fluidic drive, magnetic field control, and data acquisition functions. Various key parameters were optimized, including EDC/NHS concentration, antibody concentration, and magnetic bead size. Under the optimal conditions and using 1 μm magnetic beads as labels and an external detection magnetic field of 60 Oe, the platform successfully detected myoglobin at 75 ng/mL with ∆MR ≥ 0.202%. Specificity tests demonstrated that the platform had high specificity for myoglobin and could effectively distinguish myoglobin from bovine serum albumin (BSA) and troponin I. This study presents a rapid, accurate myoglobin detection platform that can be applied for the early diagnosis of AMI. Full article

Homogeneous fluorescence immunoassays are in high demand due to their simplicity, rapidity, sensitivity, and specificity. These methods typically utilize immune-induced changes in the rotational mobility of the fluorophore with depolarization of plane-polarized excitation light (FPIA, etc.) or fluorescence quenching based on intramolecular energy transfer (FRET, etc.). This article presents an immunoassay based on enhanced emission of the fluorescein label in immune complexes. Over the entire history of fluorescence immunoassay research, this effect has been described in a few papers, while it allows overcoming the limitations of prevailing approaches. We discovered the assay for detecting aflatoxin B1 (AFB1), a widespread toxic contaminant of agricultural products. The one-step assay procedure consists of mixing the sample with antibodies and fluorescently labeled AFB1, accompanied by fluorescence measurement. This method enables the detection of AFB1 at concentrations up to 200 pg/mL in 10 min, including measurements in complex samples (corn extracts). Minimal manipulations in the course of the testing also provide high accuracy. The AFB1 revealed in contaminated corn samples was in the range of 76–136%. The influence of immune complex formation on the fluorescent label’s emission can be easily tested and serve as a basis for applying this principle to other diverse analytes and various kinds of samples. Full article

Background: Acute Respiratory Infections are a common reason for Pediatric Emergency Department (PED) visits. Differentiating bacterial and viral infections may be challenging and might result in incorrect antibiotic prescriptions and exacerbation of antimicrobial resistance. This study evaluated the impact of new diagnostic tests in PED. Methods: A retrospective cohort of 4882 acute febrile respiratory infection cases presenting to the PED was analyzed, comparing two periods: Period 1 (October 2016–March 2017, n = 2181) and Period 2 (October 2023–March 2024, n = 2701). During Period 1, Group A Streptococcus and Respiratory Syncytial Virus rapid antigen detection tests were available. During Period 2, new point-of-care tests (POCTs), including rapid C-reactive protein and rapid antigen detection for Influenza A, Influenza B, and SARS-CoV-2, and a multiplex PCR nasal swab, were introduced. Results: In Period 2, antibiotic prescriptions decreased by 28.4%, along with a reduction in broad-spectrum antibiotic use. A significant correlation was observed between reduced antibiotic prescription and the use of new POCTs and multiplex PCR tests. Performance of blood tests and chest radiographs also decreased. Conclusions: Implementing novel diagnostic tests in PED helps clinicians select more appropriate management options with an impact on reduced stress and radiation exposure and antibiotic prescription. Full article

Zearalenone (ZEN), a stable mycotoxin with estrogenic activity produced by various Fusarium species, poses a serious food safety risk. To facilitate the rapid, sensitive, on-site detection of ZEN in maize and ensure consumer dietary safety, a colloidal gold immunochromatographic assay (CG-ICA) based on a monoclonal antibody was established. ZEN was converted via oxime derivatization into hapten ZAN-O, which was conjugated to a carrier protein to prepare an immunogen for producing a highly specific and sensitive monoclonal antibody. Then, the antibody was conjugated into colloidal gold nanoparticles (AuNPs) and used as capture bioprobes of the CG-ICA test strip. The highly sensitive and specific detection platform was established through systematic optimization of pH value, coating antigen concentration, antibody-labeling dosage, incubation time, and strip assembly conditions. Under optimized conditions, the strip exhibited a detection limit of 11.79 pg/mL and an IC₅₀ of 99.06 pg/mL, with a linear detection range of 13.40–732.48 pg/mL. In addition, the anti-interference capability assay demonstrated that the developed test strip possessed excellent specificity. In spiked maize samples, the CG-ICA test strip demonstrated recoveries ranging from 85.36% to 98.86%, with relative standard deviations (RSDs) below 10%. Thus, the CG-ICA strip provides a rapid, sensitive, and robust on-site tool for ZEN screening in maize, and can be adapted to other hazards by simply switching the antibody. Full article

Background: Short peptide epitopes are valuable for mechanistic studies, yet their intrinsic low immunogenicity and lack of commercial antibodies hinder rapid antibody generation. Methods: We developed a reproducible, sequence-level workflow combining cross-species/structural triage, independent MHC-I/II prioritization, and conservative heteroclitic-style substitutions to enhance predicted MHC affinity while preserving native epitope features. Using visfatin as a model, two optimized fragments were conjugated to KLH and tested in mice for antibody titers, isotype profiles, and binding kinetics. Results: Mutant peptides improved MHC-binding prediction, elicited stronger antibody titers, and promoted isotype maturation (increased IgG1). Importantly, antibodies maintained measurable binding to wild-type sequences, indicating preserved cross-recognition. Similar effects were reproduced with additional antigens. Conclusions: This proof-of-concept study, based on small exploratory mouse cohorts (n = 3 per group), demonstrates that strategic, minimal sequence edits can significantly enhance peptide immunogenicity while preserving native epitope recognition. This streamlined workflow provides a low-barrier route to generate epitope-directed antibodies when commercial reagents are unavailable. Full article

Backgroud/Objectives: Canine Visceral Leishmaniasis (CVL), caused by Leishmania infantum, is a significant public health concern due to dogs serving as reservoirs for human infection. An accurate and rapid diagnostic method to distinguish symptomatic and asymptomatic CVL from healthy and vaccinated animals is essential for controlling canine and human disease. Developing innovative antibody detection techniques and exploring new antigens are essential for enhancing CVL testing efficiency. Our study focuses on a multiplex flow cytometry technique to detect Leishmania-specific antibodies in canine serum. This involved conjugating small peptides with carrier proteins or peptide tags, sequences designed to facilitate bead coupling. Methods: A peptide from the L. infantum A2 protein was coupled to beads in three forms: unconjugated, conjugated with BSA, and conjugated with a C-terminal β-alanine–lysine (x4)–cysteine TAG. This TAG was previously designed to enhance peptide solubility, improve binding efficiency, and provide functional groups for covalent attachment to the beads, ensuring stable immobilization in the multiplex assay. Results: Our results suggest that the multiplex approach shows promise as a rapid serological test for CVL, particularly with TAG-conjugated peptides, which optimize bead coupling. However, peptide/BSA conjugation revealed anti-BSA antibodies in samples from healthy and CVL dogs. Conclusions: In conclusion, our findings highlight the potential of multiplex methodologies to enhance CVL diagnostics and caution against using BSA as a bead coupling agent in serological tests for canine samples due to its impact on test specificity and sensitivity. Full article

Background: Hepatitis B virus (HBV) and Plasmodium falciparum infections remain major public health concerns in sub-Saharan Africa, especially among pregnant women, who are particularly vulnerable due to physiological immunomodulation. While mono-infections are well documented, the burden and biological consequences of HBV–P. falciparum co-infection during pregnancy remain under-investigated in Gabon. Aim: To determine the prevalence, clinical relevance, and biochemical impact of HBV–P. falciparum co-infection among pregnant women in Libreville, Gabon, and to explore the interaction between viral and parasitic replication. Methods: A prospective cross-sectional study was conducted between May 2022 and May 2023 at the CHUME-FJE Laboratory in Libreville. Serum samples were tested for HBsAg using rapid diagnostic tests and ELISA confirmation; HBV surface antigen (HBsAg) levels were quantified by electrochemiluminescence (ECLIA). Parasitemia was assessed by rapid diagnostic test, microscopy, and the Lambaréné thick blood film method. Liver function parameters (ALT, AST, ALP, and GGT) were evaluated using an automated biochemistry analyzer. Statistical analysis included Mann–Whitney U tests, chi-square tests and Spearman’s rank correlation coefficient with significance set at p < 0.05. Results: Of the 222 pregnant women enrolled, HBV infection was detected in 9 cases (4.05%). Among these, 6 (2.7% of the study population) were mono-infected with HBV, while 3 (1.35%) were co-infected with Plasmodium falciparum. P. falciparum parasitemia was detected in 58 cases (26.1%). Biochemical profiles revealed elevated transaminases (AST) in HBV mono-infected women, while liver enzymes remained within normal ranges in co-infected individuals. Quantitative analyses demonstrated an inverse relationship between HBV surface antigen levels and P. falciparum parasitemia. This observation could suggest an antagonistic replication dynamic. However, the relationship was not statistically significant (Spearman’s ρ = −0.5, p = 0.67). Conclusions: HBV and P. falciparum co-infection occurs in a small but clinically relevant proportion of pregnant women in Gabon. The observed inverse replication pattern suggests a potential biological antagonism that may modulate disease severity. These findings although preliminary, could highlight the need for integrated screening and management strategies during pregnancy to improve maternal and fetal outcomes. Full article

Prostate cancer remains one of the most prevalent malignancies among men worldwide, with late-stage diagnosis contributing significantly to mortality rates. In this study, we report the development of a graphene oxide (GO)-based QCM biosensor for the early and sensitive detection of Prostate Cancer Antigen 3 (PCA3), a biomarker with higher specificity than conventional PSA tests. The sensor interface was fabricated via a layer-by-layer approach of L-cysteine, GO, and a capture probe onto a gold electrode, resulting in enhanced surface area and biomolecular recognition capacity. Structural and morphological characterizations using XRD, FE-SEM, AFM, and FT-IR confirmed the successful and uniform integration of GO and functional layers. Optimization of fabrication parameters, including EDC-NHS activation time, capture probe concentration, and target incubation time, was performed to achieve maximum sensitivity and binding efficiency. The biosensor demonstrated a distinct, concentration-dependent frequency shift upon hybridization with PCA3 targets over a range of 1.00 fM to 1.00 μM, with a calculated limit of detection (LOD) of 0.268 nM and a rapid response time of 20 min. These results underscore the potential of GO-modified QCM platforms for highly sensitive, rapid, and portable diagnostics, not only for prostate cancer screening but also for broader clinical applications involving biomarkers. Full article

Since the beginning of the 21st century, major epidemics and pandemics such as SARS, H1N1pdm09, Ebola, and COVID-19 have repeatedly challenged global systems of disease diagnostics and control. These crises exposed the weaknesses of traditional diagnostic models, including long turnaround times, uneven resource distribution, and supply chain bottlenecks. As a result, there is an urgent need for more advanced diagnostic technologies and integrated diagnostics strategies. Our review summarizes key lessons learned from four recent major outbreaks and highlights advances in diagnostic technologies. Among these, molecular techniques such as loop-mediated isothermal amplification (LAMP), transcription-mediated amplification (TMA), recombinase polymerase amplification (RPA), and droplet digital polymerase chain reaction (ddPCR) have demonstrated significant advantages and are increasingly becoming core components of the detection framework. Antigen testing plays a critical role in rapid screening, particularly in settings such as schools, workplaces, and communities. Serological assays provide unique value for retrospective outbreak analysis and assessing population immunity. Next-generation sequencing (NGS) has become a powerful tool for identifying novel pathogens and monitoring viral mutations. Furthermore, point-of-care testing (POCT), enhanced by miniaturization, biosensing, and artificial intelligence (AI), has extended diagnostic capacity to the front lines of epidemic control. In summary, the future of epidemic and pandemic response will not depend on a single technology, but rather on a multi-layered and complementary system. By combining laboratory diagnostics, distributed screening, and real-time monitoring, this system will form a global diagnostic network capable of rapid response, ensuring preparedness for the next global health crisis. Full article