Search Results (1,052)

Vector-borne protozoal infections—including babesiosis, theileriosis, hepatozoonosis, trypanosomosis, and leishmaniosis—impose a substantial burden on livestock and companion animal health worldwide and carry important zoonotic and public health implications. Accurate diagnosis is essential yet challenging, given the diversity of parasite genera, their markedly different tissue tropisms, and the uneven distribution of diagnostic resources across veterinary settings. This review provides an integrated overview of the principal diagnostic approaches available, structured around the biological logic that guides test selection in practice. Microscopic examination remains the first-line method; its strengths and limitations are discussed for intraerythrocytic parasites (Plasmodium spp., Babesia spp., Theileria spp., Cytauxzoon spp.—the latter two with additional extra-erythrocytic schizont stages in leukocytes and tissue macrophages, respectively), leukocyte-associated forms (Hepatozoon spp.), extracellular trypanosomes, and tissue-stage parasites, including emerging applications of artificial intelligence. Serological methods—enzyme-linked immunosorbent assay (ELISA), indirect fluorescence antibody test (IFAT), and point-of-care lateral flow assays—are evaluated for their role in exposure detection, population screening, and international trade certification, with attention to cross-reactivity and the active-versus-past-infection distinction. Molecular diagnostics, encompassing conventional PCR, qPCR, droplet digital PCR, isothermal amplification, and next-generation sequencing, are reviewed with respect to target selection, sensitivity, and point-of-care applicability. Finally, diagnostic challenges are contextualised within a One Health framework, highlighting the fragmentation of veterinary surveillance and the need for integrated, cross-sector approaches to detect emerging threats. Full article

Pigs play a key role in the ecology of influenza A viruses (IAVs), particularly in avian influenza (AI)-endemic regions where co-circulation of viruses from different hosts increases reassortment risk. Between September 2023 and August 2024, we surveyed pigs from Lebanon and Egypt to study IAV ecology in AI-endemic countries. Nasal swabs and sera were collected and tested using real-time RT-PCR and hemagglutination inhibition assays against avian, swine, and human seasonal IAVs. Molecular analyses identified IAV-infections in both countries, including human H1 and avian H5 subtypes, which may reflect potential cross-species transmission from humans and birds. Serologic analyses revealed prior exposure to avian, swine, and human IAVs. Avian virus seropositivity reached 4.6% (H5N1) and 15.2% (H9N2) in Egypt and 8.6% (H5N1) and 4.3% (H9N2) in Lebanon. Antibodies against human H1N1 and H3N2 were prevalent in both countries. Serologic evidence exceeded molecular detection, indicating frequent past or transient infections not captured by PCR alone. Antibody responses were significantly associated with host-level factors such as housing type, age, shaping exposure risk. These findings demonstrate repeated multisource exposure of pigs to genetically distinct IAVs in AI–endemic countries, supporting the need for integrated virologic and serologic surveillance within a One Health framework. Full article

Usutu virus (USUV) is a mosquito-borne flavivirus, widely distributed in Central Europe, where it causes avian outbreaks with large-scale mortality. Although most human infections are asymptomatic or mild, the reports of USUV neurologic infections are increasing, especially among immunocompromised patients. Cross-reactivity in serological and molecular assays is often seen between USUV and the genetically and antigenically related West Nile virus (WNV). Here, we report the first USUV infection in Greece in an asymptomatic blood donor who tested positive in the automated nucleic acid test during screening for WNV, which is endemic in the country. Following the blood donation surveillance plan, a serum sample taken two weeks post-donation was tested for WNV IgM and IgG antibodies. The borderline index of the IgM antibodies, combined with negative result for IgG antibodies, raised the suspicion of molecular cross-reactivity with USUV. Although the USUV-specific PCR in donor’s plasma was negative, its result was positive following amplification of the virus in cell culture, as USUV RNA was detected in the culture supernatant confirming the USUV infection. Whole genome sequence was taken using an Ion Torrent next-generation sequencing platform. Phylogenetic analysis showed that the Greek strain clusters within the USUV Europe 2A genetic lineage. The detection of USUV human infection in Greece prompts for surveillance studies to elucidate its epidemiology and ecology in the country. Full article

Background: Torquetenovirus (TTV) viremia is increasingly recognized as a biomarker of host immune competence. We assessed the association between baseline TTV DNA levels and immune responses to the Mpox virus (MPXV) and dengue virus (DGV) vaccines in two prospective cohorts. Methods: A total of 248 individuals were enrolled, and TTV DNA was quantified before vaccination. Humoral and cellular responses to MVA-BN (for MPXV) and QDENGA (for DGV) vaccines were measured by using serology, neutralization assays, and interferon-γ ELISpot, and correlations with TTV viremia were investigated. Results: TTV DNA was detected in 81.2% of individuals, with a significantly higher prevalence and viral loads in the Mpox-Vac group than in the DGV-Vac group. Between both groups, the only significant association observed was an inverse correlation between pre-vaccination TTV load and DGV neutralizing antibody titers in the DGV-Vac group and was limited to the subset of TTV-positive individuals; no additional correlations with antibody and T responses were identified. For the Mpox-Vac group, stratified analyses in people living with HIV (PLWH) confirmed this lack of association. Conclusions: TTV viremia does not predict vaccine immunogenicity in immunocompetent or mildly immunosuppressed individuals. These results, which derive from within-cohort analyses and do not rely on direct comparisons between heterogeneous vaccine populations, support the role of TTV as a marker of immune status along a continuum of immunosuppression, with predictive value likely confined to populations with more severe immune impairment. Full article

Nipah virus (NiV) is an animal-borne RNA virus of the genus Henipavirus that poses a significant global health threat. This threat is driven by the virus’s high mortality rate, its capacity to cause epidemics, and the lack of licensed therapeutic interventions or vaccines. Since its initial identification during the 1998–1999 outbreak in Malaysia and Singapore, recurrent episodes have occurred primarily in Bangladesh and India, with mortality rates frequently exceeding 70%. Fruit bats of the genus Pteropus serve as the biological host for the virus. Transmission to humans occurs via contact with infected wildlife, consumption of contaminated products, such as freshly harvested date palm sap, or direct person-to-person exposure. Other modes of transmission, such as transplacentally or via breast milk, are still under investigation. The clinical presentation of NiV infection varies widely, from mild flu-like symptoms to life-threatening respiratory disease and acute encephalitis. It frequently attacks the nervous system, which can lead to coma, permanent neurological damage, or relapsing encephalitis. The virus enters host cells via ephrin-B2/B3 receptors, enabling systemic dissemination and infiltration of the central nervous system. Diagnosis relies primarily on RT-PCR and serological assays, and virus isolation requires high-containment laboratories. Management remains largely supportive, as no approved antiviral therapy exists. Experimental agents, such as remdesivir, favipiravir, and monoclonal antibodies such as m102.4, have shown promise in preclinical studies. Multiple vaccine platforms—including subunit, viral vector, mRNA, and nanoparticle-based approaches—are under development, though none is yet licensed for human use. Strengthened surveillance, infection control measures, and continued research are essential to mitigate the threat posed by this emerging pathogen. This review summarizes current knowledge on NiV, including its virology, epidemiology, pathogenesis, transmission, and recent progress in therapeutic and vaccine development. Full article

The clinical cases described in this text add to the limited literature on chronic and allergic rhinosinusitis caused by dematiaceous fungi, particularly Curvularia spicifera. These cases highlight the growing recognition of fungal infections as a significant factor in the etiology of rhinosinusitis, a condition traditionally attributed to bacterial causes It has become evident that a comprehensive clinical approach, involving diagnostic imaging and laboratory examinations, particularly culture-based analysis, has been crucial in identifying the specific fungal pathogen responsible for the infection. Additionally, molecular biology techniques have proven indispensable in enhancing diagnostic accuracy and the understanding of such infections. Importantly, these types of infections are commonly observed in immunocompetent individuals, distinguishing them from other fungal infections that typically affect immunocompromised patients. This study underlines the importance of integrating microbiological findings with clinical, radiological, and histopathological data for the accurate diagnosis of non-invasive fungal rhinosinusitis, particularly given the lack of serological assays specific for this species. The available literature on these infections remains limited, and diagnosis continues to rely on an integrated multimodal approach. Full article

Understanding the molecular mechanisms underlying host immune responses to SARS-CoV-2 vaccination remains essential, particularly in populations with a high prevalence of obesity. In this cross-sectional study, we evaluated whether body mass index (BMI) is associated with vaccine-induced humoral immunity in a cohort from northeastern Mexico and discuss the findings within a structural immunology framework of spike antigenicity and antibody–epitope interactions. A total of 138 adults were recruited in Reynosa and Matamoros (June 2021–June 2022) and categorized as healthy weight, overweight, or obese according to BMI criteria. Serum anti-SARS-CoV-2 IgG was assessed using an ELISA-based assay, and differences across BMI groups were tested using the Kruskal–Wallis approach. Among all participants, 33.3% were classified as obese and 99.3% (137/138) were seropositive for anti-SARS-CoV-2 IgG. No significant differences in IgG levels were detected between BMI categories (p = 0.20). These results indicate that, in this Mexican cohort—sampled during a period of heterogeneous and often incomplete vaccination schedules—obesity was not associated with reduced detectable anti-SARS-CoV-2 IgG responses. Our findings support the need to integrate population-level serology with mechanistic studies that interrogate antibody quality (e.g., neutralization potency and epitope specificity) to better connect clinical determinants such as obesity with molecular correlates of protection. Full article

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, with anti-double-stranded DNA (anti-dsDNA) antibodies as its serological biomarkers. However, conventional anti-dsDNA antibody detection methods, which mainly rely on antibody-binding assays, often suffer from limited sensitivity and specificity, cumbersome procedures, and poor suitability for accurate clinical analysis. Herein, we developed an integrated detection system combining a circularly permuted fluorescent protein (cpFP)-based biosensor with a microfluidic chip for rapid and reliable anti-dsDNA antibody detection. The biosensor, cpR-dsAb-C1, was engineered from mApple by inserting an affinity peptide identified through phage display, enabling specific recognition of the variable region of anti-dsDNA antibodies. The biosensor exhibited good sensitivity, specificity, and anti-interference capability. Furthermore, integration of cpR-dsAb-C1 with a polydimethylsiloxane (PDMS)-based microfluidic chip yielded a microfluidic detection platform with good linearity for rapid antibody analysis. Clinical validation showed significantly higher anti-dsDNA antibody levels in patients with SLE than in healthy controls, and the results were consistent with those obtained using routine clinical methods, with an accuracy exceeding 95%. Overall, this system provides a promising low-cost, efficient, and accurate strategy for the early diagnosis and dynamic monitoring of SLE. Full article

Background/Objectives: Head and neck squamous cell carcinoma (HNSCC) remains a global public health challenge with significant morbidity and mortality. Emerging epidemiological data indicate a rising global incidence of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC). Serology for early HPV antigens has been highlighted as a relevant biomarker for HPV-associated OPSCC. This study aimed to determine the seroprevalence of HPV16 E6 antibodies in HNSCC patients in the state of Espírito Santo, Brazil. Methods: This is a prospective longitudinal cohort study in which 287 patients with HNSCC were enrolled, recruited from two oncology centers in Espírito Santo between 2011 and 2018, along with 68 cancer-free individuals. Serum samples were analyzed using the HPV16 E6 GST Capture ELISA assay. Statistical analysis was performed using SPSS. Binary logistic regression was employed to identify independent predictors of seropositivity. Results: The overall seroprevalence of HPV16 E6 antibodies was 7.3%. Seropositivity was observed in tumors of the oral cavity (6.2%) and oropharynx (13.3%). Patients with OPSCC demonstrated a significantly higher likelihood of seropositivity compared to those with tumors of the oral cavity, larynx, and hypopharynx (OR = 2.96, 95% CI: 1.21–7.28, p = 0.018). The highest frequency of HPV16 E6-positive cases occurred in tumors of the palatine tonsils (OR = 6.00; 95% CI: 1.58–22.89; p < 0.009). No seropositive cases were observed in hypopharyngeal or laryngeal tumors. Among patients with OPSCC and oral cavity squamous cell carcinoma (OCSCC), HPV16 E6 serostatus did not significantly correlate with sociodemographic, behavioral, or clinical tumor characteristics. Conclusions: Our findings reinforce the predilection of HPV-associated carcinogenesis for the oropharynx, more specifically in the palatine tonsils. In addition, this study highlights HPV16 E6 serology as a potential biomarker for HPV-driven OPSCC and underscores Brazil’s epidemiological heterogeneity, warranting standardized clinical validation. Full article

Functional antibody-dependent enhancement (ADE) represents a fundamental and context-dependent characteristic of antiviral antibody responses, reflecting the dual capacity of antibodies to mediate both the neutralization and Fc receptor-dependent enhancement of infection. In flavivirus research, this duality complicates the interpretation of conventional serological metrics and limits the reliability of single-parameter correlates of immunity, particularly in populations with complex exposure histories. Over the past decade, functional ADE assays have evolved from specialized mechanistic tools into integrated immune assessment platforms supporting translational immunology, vaccine evaluation, and population-level immune surveillance. These platforms incorporate Fcγ receptor-relevant target cell systems, standardized viral inputs, dilution series-based profiling, quantitative enhancement metrics, and structured quality control frameworks to enable reproducible, comparable, and context-aware functional measurements across cohorts and laboratories. A central concept emerging from these developments is that ADE reflects a dynamic functional immune state rather than an intrinsic property of antibodies or a direct indicator of pathological risk. Accordingly, functional ADE platforms support the contextual interpretation of antibody activity across physiologically relevant conditions, facilitating discrimination between transient functional enhancement and clinically meaningful immunological risk. By integrating functional ADE metrics with serological, cellular, and epidemiological data, these platforms provide a structured framework for interpreting immune profiles in vaccine evaluation, booster strategy design, and population-level risk stratification. This review synthesizes the development, standardization, and global dissemination of functional ADE platforms and discusses key principles governing biological relevance, analytical robustness, and inter-site transferability. Emerging directions integrating functional ADE profiling with systems immunology, immunogenomics, and computational modeling are highlighted as pathways toward predictive, decision-support-oriented frameworks. By positioning ADE platforms as immune assessment infrastructures rather than isolated assays, this review underscores their value for mechanistic inquiry, translational interpretation, and preparedness-oriented responses to emerging viral threats in the absence of definitive correlates of protection. Full article

Background: The diagnosis of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) relies on sensitive serological detection of MOG-IgG. Fixed cell-based assays (CBAs) may yield low-positive or borderline results that complicate early clinical decision-making, whereas live CBAs—recommended as the reference method—preserve native antigen conformation and offer higher analytical sensitivity. Importantly, low-positive titres should not be confused with true seronegativity, as they may nevertheless be clinically meaningful. Case Presentation: A 14-year-old previously healthy male presented with left optic neuritis and perineuritis following an upper respiratory infection. Initial MOG-IgG testing on a fixed CBA was low-positive (1:10). He partially responded to intravenous methylprednisolone and required intravenous immunoglobulin (IVIG) for complete resolution. Over three years, he experienced sequential, steroid-dependent bilateral optic neuritis with perineuritis, relapsing on every steroid taper. Rituximab and subsequently mycophenolate mofetil failed to induce remission. Repeat testing with a live CBA at a reference laboratory yielded a high-positive MOG-IgG titre of 1:1000, confirming MOGAD. Tocilizumab (8 mg/kg every 4 weeks) was initiated and allowed complete corticosteroid withdrawal. At age 18, the patient remained asymptomatic, with an Expanded Disability Status Scale score of 0, best-corrected visual acuity of 20/20 in both eyes, and stable peripapillary retinal nerve fibre layer thickness on spectral-domain optical coherence tomography. Conclusions: In paediatric patients with recurrent optic neuritis with perineural involvement and borderline fixed-CBA results, confirmatory testing with a live CBA at a reference laboratory should be considered to avoid diagnostic delay and therapeutic misdirection. In refractory, steroid-dependent cases, IL-6 receptor blockade may represent a reasonable therapeutic option, in line with emerging evidence. Full article

Livestock farming represents a key economic activity in the Tataouine Governorate of southern Tunisia, where cattle and dromedary camels coexist. Varicellovirus bovinealpha1 (BoAHV-1), the etiological agent of infectious bovine rhinotracheitis (IBR), primarily affects cattle, while its circulation in camelids remains poorly understood. Following recent European Union regulations requiring BoAHV-1 surveillance in multiple animal species, this short communication reports serological findings from dairy cattle and dromedary herds in southern Tunisia. In March 2024, serum samples were collected from four non-vaccinated farms, including two intensive Friesian dairy cattle herds and two extensive dromedary herds (50 animals each). Serum samples from all animals were tested for BoAHV-1 antibodies using competitive commercial gB- and gE-based enzyme-linked immunosorbent assays (c-ELISA) and confirmed by virus neutralization test (VNT). Antibodies against BoAHV-1 were detected in cattle from both dairy farms, with low seroprevalence and neutralizing antibody titers, indicating past or ongoing exposure. In contrast, all dromedary samples tested seronegative by both c-ELISA and VNT. These findings confirm BoAHV-1 circulation in cattle in the Tataouine region and its absence in dromedaries at sampling. Further studies involving larger sample sizes and molecular investigations are required to clarify the potential role of camelids in BoAHV-1 epidemiology in southern Tunisia. Full article

The diagnosis of coccidioidomycosis is often achieved serologically by the detection of antibodies against fungal antigens. While several serologic tests are available for coccidioidomycosis, all of them are performed in a laboratory setting causing delays in diagnosis and therapeutic intervention. Point-of-care testing offers the ability to provide a shorter time to result by avoiding specimen send-out, minimizing processing steps, and employing expeditious immunochemical techniques. A preliminary trial of a rapid anti-coccidioidal antibody lateral flow assay (LFA) using fingerstick blood was performed on 22 patients with coccidioidomycosis at the point of care during outpatient clinic visits. Patients were tested longitudinally over the course of one year. An LFA reader was implemented to provide an objective result by quantifying the intensity of the test line band. There was close qualitative concordance observed between positive LFA results with send-out immunodiffusion (89.5%) and complement fixation (78.4%) standard of care clinical laboratory assays. Additionally, the relationship between LFA test line density values and traditional complement fixation antibody titers was assessed. Full article

The COVID-19 pandemic highlighted the critical role of serological assays in understanding antiviral immune responses, monitoring vaccine efficacy, and informing public health strategies. This review provides a comprehensive overview of commonly used SARS-CoV-2 antibody detection methods, focusing on binding and neutralization assays. Antibody binding assays, including enzyme-linked immunosorbent assays (ELISAs), chemiluminescence immunoassays (CLIAs), lateral flow immunoassays (LFAs), and multiplex platforms, enable the rapid and high-throughput detection of immunoglobulin isotypes against various viral antigens. Neutralization assays, including live-virus, pseudovirus (PsV), and surrogate assays, offer functional insights into the ability of antibodies to prevent viral entry, though they often require higher biosafety levels and optimization. Serological assays, primarily antibody binding assays and several surrogate neutralization assays, received Emergency Use Authorization (EUA) during the pandemic, supporting seroprevalence efforts. Antibody binding assays and neutralization assays were also widely used in vaccine immunogenicity studies. Despite many standardization initiatives, assay standardization and data harmonization remain challenging and require further efforts. The choice of assay should be guided by study goals: antibody binding assays are preferred for high-throughput monitoring and epidemiological studies, while neutralization assays are essential for assessing functional immunity and variant-specific neutralization and protection. Full article

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease linked to epidermal barrier dysfunction, Th2-skewed immune polarization, and disrupted gut microbiota homeostasis. While probiotic interventions show promise in managing AD, the mechanisms governing strain-specific efficacy—particularly systemic modulation via the “gut–skin axis”—remaining to be fully elucidated. Methods: This study systematically compared the oral therapeutic effects of three Lacticaseibacillus rhamnosus strains (MG-A047, MG-A054, and LGG) in a 2,4-dinitrochlorobenzene (DNCB)-induced AD mouse model. Results: By integrating behavioral, histopathological, and serological assessments with 16S rRNA-based gut microbiota profiling and in vitro functional assays, this study offers a multidimensional evaluation of the strain-specific advantages and potential therapeutic mechanisms of three L. rhamnosus strains. The results demonstrate that MG-A054 most effectively alleviated cutaneous inflammation and pruritus, significantly reduced serum IgE and IL-4 levels, and attenuated epidermal hyperplasia and inflammatory cell infiltration (including mast cells and eosinophils). Mechanistically, this strain may directly inhibit hyaluronidase activity and mast cell degranulation, and specifically remodel the gut microbiota structure, thereby promoting a shift toward a healthier functional profile. Conclusions: These findings suggest that the superior efficacy of MG-A054 may be achieved through coordinated modulation of the gut–skin axis and related pathways. This study offers new mechanistic clues for understanding the strain-specific actions of probiotics and lays a preclinical foundation for the further development of MG-A054 as a potential targeted microecological therapy for AD. Full article