Search Results (971)

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

Neutralizing antibodies (nAbs) are key indicators of protection against SARS-CoV-2, and their measurement remains essential for monitoring vaccine responses and population immunity. While the plaque reduction neutralization test (PRNT) is the gold standard, it relies on replicative viruses and is not suited for high-throughput applications. Here, both an in-house and a commercial pseudovirus-based neutralization (PBN) assay were standardized and compared with PRNT to assess performance and concordance. The in-house PBN employed a VSV-ΔG pseudovirus encoding NanoLuc and displaying the SARS-CoV-2 Spike from the Wuhan or Omicron BA.1 variants in HEK293T-hACE2 cells, whereas the commercial assay (Integral Molecular, Philadelphia, PA, USA) used a lentiviral backbone with Renilla or GFP reporters and Wuhan or Omicron XBB.1.5/XBB.1.9 Spikes in Vero E6-ACE2-TMPRSS2 cells. Both assays showed strong correlations with PRNT, the commercial assay; moreover, they offered superior reproducibility and scalability, while the in-house version provided a cost-effective alternative suitable for BSL-2 settings. A total of 600 serum samples from vaccinated individuals were analyzed by commercial PBN at collection time points, from pre-vaccination to twelve months post–second dose, enabling large-scale screening, revealing marked differences in neutralization between Wuhan and Omicron XBB.1.5/1.9, and allowing unbiased classification of low, medium, and high responders using k-means clustering. The geometric mean titers (log₁₀ GMT) highlighted a ~1.5 log₁₀ (eightfold) reduction in neutralizing activity against Omicron, reflecting antibody waning and antigenic drift. Altogether, this study integrates assay standardization, PRNT comparison, and large-scale immune profiling, establishing a robust framework for harmonized pseudovirus-based neutralization testing. Full article

Dried blood spots (DBSs) are a practical tool for diagnosing infectious diseases, especially in remote or resource-limited settings. This study assessed the efficacy of DBS-based serological assays for syphilis screening. EDTA blood samples from 171 syphilis-seropositive and 122 seronegative individuals were used to prepare DBSs by spotting whole blood onto filter paper. After drying, 12 mm disks were punched, incubated overnight in buffered solution, and centrifuged. Syphilis serological screening was conducted using the Liaison^® Treponema Screen assay, Macro-Vue™ Reagin Plasma Rapid (RPR) card test, and Dual Path Platform (DPP) Syphilis Screen and Confirm test. The Liaison^® assay demonstrated 100% sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with an optimized cut-off. The nontreponemal RPR test showed very low sensitivity (2.9%) on DBS but perfect specificity (100%). The DPP test for treponemal antibodies achieved high sensitivity (92.1%) and specificity (98.2%) with microreader adjustment. Visual reading of the DPP test had variable accuracy, with sensitivity reaching 100% but lower specificity (42.1%). Nontreponemal antibody detection by DPP showed moderate sensitivity and specificity. Although nontreponemal testing requires refinement, DBS testing combined with point-of-care tests like DPP holds promise for expanding syphilis screening accessibility and decentralization globally, particularly in resource-constrained environments. Full article

Since its discovery in 2019, SARS-CoV-2 has continued to be detected in both humans and animals worldwide. Currently there is limited research focusing on serological surveillance of wildlife under human care. Here we tested 230 serum samples of 134 animals from two zoological institutions collected between 2015 and 2024. To assess prior exposure and antibody responses from natural infection or vaccination, we used three serological assays: a nucleocapsid protein-based ELISA (N-ELISA), a surrogate virus neutralization test (sVNT) for spike (S) protein and a neutralization assay with S-pseudotyped viral particles. Among the 114 samples collected from 58 animals at Fort Wayne Zoo in Indiana, 37 samples from 20 vaccinated animals were sVNT-positive, and 2 of the positive animals had 2 samples prior to vaccination that tested positive by N-ELISA. Of the 116 samples from 76 animals at Brookfield Zoo in Illinois, 20 samples of 20 animals were sVNT-positive, and 19 of the positive animals had been vaccinated. Among these 20 sVNT-positive samples, only one sample from a South American Tapir was positive from prior to vaccination and 1 sample from a sloth bear was also positive by N-ELISA, marking the first documented cases of SARS-CoV-2 exposure in both species. Neutralization assays with S-pseudotyped virus revealed that some of the sVNT-positive samples have strong activity against the WH1-S pseudovirus but showed significantly reduced neutralization against the Omicron LP.8.1-S pseudovirus. These results underscore the need for updated vaccines tailored to emerging variants. Overall, our findings highlight the importance of continued serological surveillance across multiple species to detect new SARS-CoV-2 exposures and monitor vaccine-induced immunity in captive animal populations. Full article

Acute Myocardial Infarction (AMI) is a critical cardiac condition that poses a substantial threat to myocardial function. Expedient diagnosis of AMI is paramount and relies on serological assays for rapid and accurate quantification of relevant biomarkers. Electrochemical sensors have emerged as promising candidates for this application, owing to their accessibility, operational simplicity, and high specificity. In this study, we developed a paper-based electrochemical immunosensor to detect cardiac troponin I in serum and saliva specimens. The electrode was fabricated using screen-printing technology with photographic paper as the substrate, employing graphite-based ink, nail polish, and acetone as the solvent. A quasi-reference electrode was constructed using silver powder-based ink, nail polish, and acetone. The immunosensor was prepared by modifying the working electrode with gold nanoparticles (AuNP) functionalized with cardiac troponin I antibodies (anti-cTnI) and bovine serum albumin (BSA). This modified electrode was subsequently used to detect the troponin I antigen. The analyses were performed in 0.1 mol L⁻¹ phosphate buffer medium, pH 7.00, in the presence of 5.0 mmol L⁻¹ of the potassium ferrocyanide probe. The immunosensor exhibited a sensitivity of 0.006 µA/fg mL⁻¹, a limit of detection of 9.83 fg mL⁻¹, and a limit of quantification of 32.79 fg mL⁻¹. Specificity studies conducted in the presence of other macromolecules demonstrated minimal interference, with relative standard deviations (RSD) below 5.00%, indicating a specific interaction with troponin I. Furthermore, the immunosensor demonstrated excellent reproducibility and stability. Upon application to serum and saliva samples, the immunosensor presented recoveries of approximately 99–105%, suggesting its potential applicability in clinical analyses. Full article

Background: Lyme borreliosis (LB) constitutes a major challenge for Public Health, particularly in regions where surveillance and diagnostic systems are underdeveloped or fragmented. Despite its potential as a hotspot for tick-borne diseases, Sardinia (Italy) remains poorly explored in terms of LB epidemiology. Methods: A sero-prevalence study was conducted on serum samples stored in the biobank of a hospital in Northern Sardinia. The serum library consisted of serum samples collected on the basis of a diagnostic hypothesis of rheumatic disease. Serological testing for antibodies against Borrelia was performed using the indirect immunofluorescence assay (IFA) and enzyme-linked immunosorbent assays (ELISA), followed by confirmation by Western blot for positive results. The study analyzed 58 serum samples from patients selected based on clinical symptoms compatible with Borrelia spp. infection. Results: Among the 58 patients, 9 (15.5%) yielded positive results, with absorbance values higher than those of the positive control, suggesting that the pathogen is widespread but poorly recognized in Sardinia. The results are in line with broader trends in the Mediterranean, indicating that Sardinia can no longer be considered a marginal area for Borrelia spp. circulation. Conclusions: The status of Sardinia as a sentinel territory underlines the need for enhanced epidemiological surveillance within the One Health approach, including human, animal and environmental health. Full article

Background/Objectives: Understanding the seroepidemiology of P. falciparum antibody responses is essential for assessing the acquisition of natural immunity and may guide interventions that impact the acquisition of immunity against malaria in endemic areas. This study assessed the association between antigen-specific IgG responses and protection against P. falciparum infection in children from Burkina Faso. Methods: Children aged 1.5 to 12 years were followed using cross-sectional and longitudinal approaches. IgG responses to 16 P. falciparum antigens were measured using a multiplex assay and analyzed by age group and malaria infection status. Associations between antibody levels and clinical malaria risk were assessed using incidence rate ratios (IRRs), and predictive performance of antibody combinations was evaluated using ROC analysis. Results: IgG responses to AMA1, CSP, and MSP2 CH150 showed weak but significant positive correlation with age. Children aged 5–12 years had higher antibody levels than younger children aged 1.5–5 years. Uninfected children had higher levels of antibodies to EBA181 RIII-V, Rh5.1, and SEA1, while infected children had elevated AMA1 and MSP2 CH150. Anti-GLURP R2 and anti-Rh5.1 antibodies were associated with reduced malaria risk (adjusted IRR = 0.52 and 0.40, respectively). The antibody combination of AMA1, GLURP R2, and Etramp5 Ag1 showed the best predictive performance (AUC = 0.70). Conclusions: This study underlines the value of less-studied antibodies (Etramp5 Ag1, Rh5.1, HSP40 Ag1) for diagnosing and protecting against malaria, opening up prospects for the development of more effective tests and targeted vaccine approaches. The variability of responses according to age and infection status calls for further studies to optimize prevention strategies. Full article

The Goose/Guandong lineage of highly pathogenic avian influenza virus [A/Goose/Guangdong/1/1996(H5N1)] is the progenitor of the currently circulating Eurasian-lineage highly pathogenic avian influenza H5N1 clade 2.3.4.4b and has been the most consequential highly pathogenic avian influenza lineage globally. Despite increased reports of infections, the extent of exposure and role of wild mammals in the ecology and transmission dynamics of the virus remains poorly understood. We surveyed wild mammals in Ohio, United States to investigate the potential spillover of highly pathogenic H5N1 avian influenza clade 2.3.4.4b. While no active infections—defined as positive results indicative of viral replication and potential propagation—were detected by swab-based molecular tests, serological assays revealed antibodies against multiple avian influenza virus antigens in raccoons and opossums. Specifically, antibodies to avian influenza virus nucleoprotein were detected in 54.9% (n = 61) of samples using enzyme-linked immunosorbent assay; antibodies to Eurasian-lineage highly pathogenic avian influenza H5 clade 2.3.4.4b and North American low pathogenic avian influenza H5 were detected in 43.2% (n = 48) and 22.5% (n = 25) of samples, respectively, using virus neutralization assays; and antibodies to avian influenza virus neuraminidase were detected in 44.1% (n = 49) of samples using enzyme-linked lectin assay. All seropositive animals were sampled at Ohio marshes with previously confirmed highly pathogenic avian influenza H5N1 detections in waterfowl. These findings suggest prior exposure of wild mammals to these viruses without mortality events. Wild mammals may play an intermediary role in the mammalian adaptation of avian influenza A viruses. Therefore, ongoing surveillance of wild mammals is crucial for assessing the risk to public health. Full article

The Orthobunyavirus Oropouche (OROV) has become an urgent public health threat in Central and South America, as well as in other countries worldwide. Since its initial identification, there have been over 30 outbreaks, with the largest reported in late 2024 in Brazil. This outbreak prompted an epidemiological alert due to a significant increase in OF cases in non-Amazonian states in the Americas region, as well as in European countries, where 44 imported cases were identified. Humans become infected predominantly through the bite of the Culicoides paraensis midge, and the symptoms could be misinterpreted due to their similarity to those of other arboviral infections. Due to the lack of a point-of-care test, RT-qPCR is currently the key diagnostic test during the acute phase of the disease. This review focuses primarily on the available molecular and serological diagnostic methods. The latter could indeed be used as a confirmation test to monitor the patient’s immunological status and better distinguish between cross-reacting arboviruses. In addition, this review explains also the existing sequencing methods required to enforce the surveillance system for OROV reassortant species that could cause a new worldwide outbreak. The information gathered could provide a valuable basis for implementing additional surveillance systems in those countries lacking up-to-date data. Full article

Avian influenza A viruses pose ongoing threats to human and animal health, with H7 subtypes causing outbreaks globally. In Mexico, highly pathogenic H7N3 viruses have circulated in poultry since 2012, causing sporadic human infections. Here we analyzed genetic markers in hemagglutinin sequences from Mexican H7N3 isolates and conducted serological assays on human populations with poultry exposure. Our results show conserved avian-like receptor binding sites, thus limiting human adaptation, alongside antigenic drift and acquisition of glycosylation sites likely driven by vaccination. Serological testing of 1103 individuals revealed no detectable antibodies against H7N3, indicating a naïve population. Phylogenetic analyses revealed multiple virus clades circulating regionally. These findings suggest that while current H7N3 viruses have limited capacity for sustained human transmission, the lack of population immunity underscores the importance of continued surveillance and risk assessment to mitigate potential pandemic threats. Full article

Background: Peste des petits ruminants (PPR) is an acute or subacute contagious trans-boundary viral disease causing high morbidity and mortality in domestic and wild small ruminants. The national UAE-PPR control and eradication plan follows the PPR Global Control and Eradication Strategy (PPR GCES) and relies on the annual mass vaccination of small ruminants to eradicate the disease from the country by 2030. Despite the immunization effort against PPR, the vaccination coverage reached 65% at maximum, which necessitates conducting a post-vaccination evaluation (PVE) study at the national level. Methods: Using multistage random sampling to assess the PPR vaccine and vaccination effectiveness, protocol (2) of the PPR GCES, using two serosurveys; serosurvey (1) (pre-vaccination) at day 0 before vaccination, to assess the primary PPR serological investigation, and serosurvey (2) at (30–90) days post-PPR vaccination, to evaluate the immune response, were carried out from September to December 2024 across the seven Emirates of the UAE. The nucleoprotein-based competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect PPR antibodies in a total of 1592 and 1589 sera samples collected, respectively, before and after vaccination from different (n = 163) sheep and goats holdings (epi-unit) distributed in the different Emirates of the UAE. Results: In serosurvey (1). prior to vaccination, out of the total 1592 samples tested (839 goats and 753 sheep), 833 animals (52.32%) were found to be seropositive for PPR antibodies. In contrast, in serosurvey (2), after vaccination, 1490 (93.77%) animals were found to be seropositive out of the total 1589 small ruminants (825 goats and 764 sheep) tested by c-ELISA. A statistically significant increase (41.45%) in the overall seroprevalence from (52.32%) pre-vaccination to (93.77%) post-vaccination was observed. Post-vaccination, 93.87% (n = 153) of the vaccinated epi-units achieved more than 70% seroprevalence compared to 43.56% (n = 71) before vaccination. Prediction analysis showed that all the seven UAE Emirates require 1.2 years maximum to reach 100% immune-protection levels. Conclusions: An efficient PPR vaccine was used to immunize small ruminants in the UAE. Higher (89.47–100%) post-vaccination herd immunity than the threshold recommended by the PPR GCES (>80% immunity) was attained, which can efficiently break the spread of PPRV within the UAE. To enhance the eradication of PPR I the UAE, conducting mass vaccination campaigns targeting over the (95%) immunization coverage of eligible animals for the next three years is recommended to attain the requested sustained (>80%) immunity at the animals holding level. Full article

Background: The accurate and rapid genotyping of ABO (chromosome 9q34.2) blood types is critical for clinical diagnostics and transfusion medicine, particularly in scenarios where serological methods yield uncertain results, such as in neonatal testing or with rare ABO subtypes. Methods: This study describes a loop-mediated isothermal amplification (LAMP)-based method for ABO genotyping that offers a faster and more cost-effective alternative to conventional PCR-based techniques. Results: The method targets four key single nucleotide polymorphisms (SNPs) at positions 261, 297, 703, and 930, allowing for the differentiation of common A, B, and O blood types, as well as the rare AB subtype B(A)01. The detection of the B(A)01 subtype is clinically important for preventing transfusion mismatches where serology may be inconclusive. Operating at a constant temperature, the assay can be completed in under an hour without the need for a thermocycler, offering significant time and cost benefits over qPCR. The method demonstrated high specificity, demonstrating detection down to 10 copies across all assays. When validated against a gold-standard method on clinical blood samples, the LAMP assay showed high accuracy (95% C value calculated via binomial exact method): 97.4% for type O, 98.7% for type A, 98.7% for type B, and 100% for the B(A)01 subtype. To enhance usability for point-of-care applications, freeze-dried reagents were developed that permit direct loading of lysed blood samples while maintaining high performance. Conclusions: This simplified and robust format positions the LAMP assay as a promising tool for rapid and reliable ABO genotyping in diverse clinical settings. Full article

Chicken infectious anemia virus (CIAV) causes immunosuppression in poultry, leading to substantial global economic losses through both vertical and horizontal transmission. Since 2014, frequent outbreaks have been reported in southern China; however, the epidemiology of CIAV in Guangdong Province remains poorly defined. Between July 2018 and March 2022, we collected 105 tissue samples and 786 serum samples from poultry in nine cities. PCR/qPCR assays targeting the VP1 gene confirmed CIAV infection, and positive tissues inoculated into MSB1 cells yielded four isolates (GDHZ1, GDHZ2, GDJM, GDLF). Phylogenetic analysis demonstrated that GDHZ1, GDJM, and GDLF clustered within clade A1, whereas GDHZ2 belonged to clade A2. All isolates shared glutamine (Q) at position 394, together with virulence-associated amino acid signatures (75V, 89T, 125L, 139K, 141Q, 144E). Serological testing indicated a high prevalence, with 627 of 786 samples positive (79.77%). The relatively low proportion of virus-positive tissues and successful isolations may reflect viral tropism or limitations in detection sensitivity. These findings enhance understanding of CIAV molecular epidemiology in Guangdong and provide evidence to inform surveillance, vaccination strategies, and control measures. Full article

Background: Mycoplasma pneumoniae is a common cause of respiratory tract infections in children, but neurological complications, including encephalitis, are increasingly recognized. Basal ganglia involvement is rare, and a poorly characterized feature of meningoencephalitis, with clinical consequences being inconclusive. Methods: We report two pediatric cases of Mycoplasma pneumoniae-related meningoencephalitis with bilateral basal ganglia lesions seen on MRI. A literature review was conducted using PubMed, Scopus, and Web of Science to identify reports of M. pneumoniae-related meningoencephalitis in children, and related MRI findings. Results: Both patients (12-year-old male and 14-year-old female) presented with acute meningoencephalitis syndrome and had marked mononuclear pleocytosis. In both patients M. pneumoniae was confirmed with serological assay from serum sample, while in one patient M. pneumoniae was also confirmed by PCR from pharyngeal swab. Both exhibited bilateral basal ganglia lesions, with complete regression observed during follow-up. Treatment with corticosteroids led to full recovery in both cases. After a literature search, a total of 21 patients had basal ganglia involvement reported. Conclusions: Literature suggests variable MRI findings in pediatric M. pneumoniae encephalitis, with basal ganglia involvement being uncommon and rarely reported, especially among older children. While diagnostic challenges related to extrapulmonary manifestations of the infection persist, basal ganglia involvement could aid in diagnosis, especially in older children presenting with meningoencephalitis along with pronounced pleocytosis when respiratory symptoms are absent or mild. Full article

Background: In the Kingdom of Saudi Arabia, various COVID-19 vaccines were administered during the pandemic. However, region-specific real-word comparative data on their immunogenicity remain limited. This study aimed to assess the serological responses to Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and AstraZeneca (ChAdOx1 nCoV-19) vaccines in a diverse population living in KSA. Methods: This observational study included 236 adults recruited from vaccination sites in Riyadh. Participants provided serum samples at predefined intervals: before the first dose, after the first dose, after the second dose, and post-vaccination infection (if applicable). IgG and neutralising antibodies were quantified using ELISA assays. Demographic and vaccination data, and their associations with antibody responses, were evaluated. Results: At baseline, 75.4% of participants were positive for SARS-CoV-2 IgG, suggesting high prior exposure. Marked incremental increases in IgG levels were observed after each vaccine dose. Both Moderna and Pfizer elicited stronger responses, with Pfizer inducing the strongest early response and Moderna achieving the highest overall titres. Among IgG-positive individuals, neutralising antibodies were detected in 98.1%. There were no statistically significant differences by age or gender, although males tended to show higher mean titres. Heterologous vaccine schedules induced comparable or enhanced immunogenicity relative to homologous schedules, supporting their use in flexible immunisation strategies. Conclusions: All COVID-19 vaccines administered in Saudi Arabia elicited robust antibody responses, particularly the mRNA-based vaccines. Our findings support their continued use and justify varied vaccination approaches, including mix-and-match booster strategies, to enhance community immunity. Full article