The global distribution and burden of dengue

Estimating Dengue Outbreak Thresholds in West Africa: A Comprehensive Analysis of Climatic Influences in Burkina Faso, 2018-2024

BACKGROUND

Dengue, transmitted by Aedes spp. mosquitoes, poses significant public health challenges in Burkina Faso. This study investigated outbreak thresholds, utilizing historical data since 2018 to explore the climatic impacts on dengue transmission and address knowledge gaps.

METHODOLOGY

This retrospective ecological study utilized historical and contemporary data from Burkina Faso's Public Health Ministry (2018-2024) to model dengue outbreak thresholds. A combination of epidemic channel analysis, joinpoint regression, climate-disease relationship analysis, and negative binomial regression was employed to provide comprehensive insights into the factors driving dengue outbreaks.

PRINCIPAL FINDINGS

The incidence of probable dengue cases remained stable, mostly below 5 cases per 100,000 people, except for a sharp surge in week 40 of 2023, peaking at 38 cases per 100,000. This surge was brief, normalizing by week 47, but coincided with a marked increase in mortality, reaching 90 deaths in week 45. Joinpoint regression identified key thresholds, an alert at 2.1 cases per 100,000 by week 41 and an intervention threshold at 19.1 cases by week 44, providing a framework for timely public health responses. Climatic factors significantly influenced dengue transmission, with higher temperatures (RR = 2.764) linked to increased incidence, while higher precipitation (RR = 0.551) was associated with lower case numbers, likely due to disrupted mosquito breeding conditions. Additionally, intermediate precipitation levels showed a complex relationship with higher incidence rates.

CONCLUSIONS

This study established evidence-based epidemiological thresholds for dengue outbreak detection in Burkina Faso (2018-2024), demonstrating temperature as a primary transmission driver while precipitation showed inverse relationships. Analysis of the 2023 outbreak identified a critical five-week intervention window (weeks 40-45), providing a framework for climate-sensitive early warning systems. These findings advance the understanding of dengue dynamics in West Africa, though future research should integrate geographical and socioeconomic variables to enhance predictive modeling and outbreak preparedness.

Analysing dengue fever spread in Kenya using the Zero-Inflated Poisson model

Background

Dengue fever (DF), transmitted by Aedes mosquitoes, remains a major public health concern in tropical and subtropical regions. Understanding the influence of climatic variables on DF incidence is essential for improving outbreak prediction and control measures.

Aim

This study analysed the impact of climatic factors on DF incidence in Kenya using a Zero-Inflated Poisson (ZIP) model.

Setting

The study focused on DF cases in Kenya from 2019 to 2021.

Methods

A ZIP model was applied to monthly dengue case data and associated climatic variables, such as temperature, rainfall, and humidity. The model addresses over-dispersion and excess zeros in the data, providing a more accurate depiction of DF dynamics.

Results

The ZIP model revealed significant associations between climatic variables and DF incidence. Humidity (β = 0.0578, standard error [s.e.] = 0.0024, z = 24.157, p < 2e-16) and temperature (β = 0.0558, s.e. = 0.0053, z = 10.497, p < 0.01) showed a positive relationship with dengue cases, while rainfall (β = -0.0045, s.e. = 0.0003, z = -16.523, p < 0.01) had a significant negative effect. The over-dispersion test confirmed excess variability in the data (O statistic = 456.3, p = 0.004), and the Vuong test supported the use of the ZIP model over a standard Poisson model. Model comparison indicated superior fit for the ZIP model (akaike information criterion [AIC] = 5230.959 vs. 27061.367 for Poisson), effectively accounting for zero-inflation.

Conclusion

The results suggest that higher humidity and temperature favor dengue transmission, while heavy rainfall may disrupt mosquito breeding, reducing cases. These findings provide a basis for targeted public health interventions.

Contribution

This study enhances understanding of DF-climate interactions in Kenya, supporting the application of ZIP modelling for improved disease surveillance and control strategies.

Identification and evaluation of bioactive compounds from Azadirachta indica as potential inhibitors of DENV-2 capsid protein: An integrative study utilizing network pharmacology, molecular docking, molecular dynamics simulations, and machine learning techniques

Background

Dengue fever is a viral disease caused by the dengue flavivirus and transmitted through mosquito bites in humans. According to the World Health Organization, severe dengue causes approximately 40,000 deaths annually, and nearly 4 billion people are at risk of dengue infection. The urgent need for effective treatments against the dengue virus has led to extensive research on potential bioactive compounds.

Objective

In this study, we utilized a network pharmacology approach to identify the DENV-2 capsid protein as an appropriate target for intervention. Subsequently, we selected a library of 537 phytochemicals derived from Azadirachta indica (Family: Meliaceae), known for their anti-dengue properties, to explore potential inhibitors of this protein.

Methods

The compound library was subjected to molecular docking to the capsid protein to identify potent inhibitors with high binding affinity. We selected 81 hits based on a thorough analysis of their binding affinities, particularly those exhibiting higher binding energy than the established inhibitor ST-148. After evaluating their binding characteristics, we identified two top-scored compounds and subjected them to molecular dynamics simulations to assess their stability and binding properties. Additionally, we predicted ADMET properties using in silico methods.

Results

One of the inhibitors, [(5S,7R,8R,9R,10R,13R,17R)-17-[(2R)-2-hydroxy-5-oxo-2H-furan-4-yl]-4,4,8,10,13-pentamethyl-3-oxo-5,6,7,9,11,12,16,17-octahydrocyclopenta[a]phenanthren-7-yl] acetate (AI-59), showed the highest binding affinity at -10.4 kcal/mol. Another compound, epoxy-nimonol (AI-181), demonstrated the highest number of H-bonds with a binding affinity score of -9.5 kcal/mol. During molecular dynamics simulation studies, both compounds have exhibited noteworthy outcomes. Through molecular mechanics employing Generalized Born surface area (MM/GBSA) calculations, AI-59 and AI-181 displayed negative ΔG_bind scores of -74.99 and -83.91 kcal/mol, respectively.

Conclusion

The hit compounds identified in the present investigation hold the potential for developing drugs targeting dengue virus infections. Furthermore, the knowledge gathered from this study serves as a foundation for the structure- or ligand-based exploration of anti-dengue compounds.

Mosquito Cell Atlas: A single-nucleus transcriptomic atlas of the adult Aedes aegypti mosquito

The female mosquito's remarkable ability to hunt humans and transmit pathogens relies on her unique biology. Here, we present the Mosquito Cell Atlas (MCA), a comprehensive single-nucleus RNA sequencing dataset of more than 367,000 nuclei from 19 dissected tissues of adult female and male Aedes aegypti, providing cellular-level resolution of mosquito biology. We identify novel cell types and expand our understanding of sensory neuron organization of chemoreceptors to all sensory tissues. Our analysis uncovers male-specific cells and sexually dimorphic gene expression in the antenna and brain. In female mosquitoes, we find that glial cells in the brain, rather than neurons, undergo the most extensive transcriptional changes following blood feeding. Our findings provide insights into the cellular basis of mosquito behavior and sexual dimorphism. The MCA aims to serve as a resource for the vector biology community, enabling systematic investigation of cell-type specific expression across all mosquito tissues.

Druggable genome screens identify SPP as an antiviral host target for multiple flaviviruses

Mosquito-borne flaviviruses, such as dengue virus (DENV), Zika virus (ZIKV), West Nile virus, and yellow fever virus, pose significant public health threats globally. Extensive efforts have led to the development of promising highly active compounds against DENV targeting viral non-structural protein 4B (NS4B) protein. However, due to the cocirculation of flaviviruses and to prepare for emerging flaviviruses, there is a need for more broadly acting antivirals. Host-directed therapy where one targets a host factor required for viral replication may be active against multiple viruses that use similar replication strategies. Here, we used a CRISPR-Cas9 library that we designed to target the druggable genome and identified signal peptide peptidase (SPP, encoded by Histocompatibility Minor 13, HM13), as a critical host factor in DENV infection. Genetic knockout or introducing mutations that disrupt the proteolytic activity of SPP markedly reduced the replication of multiple flaviviruses. Although their substrates differ, SPP has structural homology with γ-secretase, which has been pursued as a pharmacological target for Alzheimer's disease. Notably, SPP-targeting compounds exhibited potent anti-DENV activity at low nanomolar concentrations across multiple primary and disease-relevant cell types, acting specifically through SPP inhibition rather than γ-secretase inhibition. Importantly, SPP inhibitors were active at low nanomolar concentrations against flaviviruses other than DENV including ZIKV while DENV NS4B inhibitors lost activity. This study emphasizes the strong potential of SPP as a pan-flaviviral target and provides a framework for identifying host druggable targets to screen for broad-spectrum antivirals.

Kinetics of NS1 and anti-NS1 IgG following dengue infection reveals likely early formation of immune complexes in secondary infected patients

Dengue virus (DENV) is a major health concern throughout the world infecting up to 390 million people globally each year. Infection with any one of the four DENV serotypes produces a spectrum of clinical illness ranging from a mild undifferentiated febrile disease through to severe dengue involving fever and haemorrhage. There is currently no antiviral treatment for dengue and only one licensed vaccine with limited distribution. This study characterises the kinetics of the serological dengue biomarker, NS1, and the appearance of anti-NS1 IgG, anti-E IgM and anti-E IgG responses in patients with primary and secondary infections. Blood samples were collected daily from a cohort of 52 Vietnamese patients during the acute phase of disease. NS1 was detected in 85% of patient samples from disease onset with detection decreasing throughout the acute phase of disease. Anti-NS1 IgG detected from the fourth day of illness and anti-E IgM and IgG from the third day of illness, were all observed to increase throughout the course of the disease. During secondary infection, NS1 levels rapidly decrease with the increasing levels of anti-NS1 IgG, suggesting the possibility of NS1 immune complex formation and a potential role in the pathogenesis of the severe forms of disease associated with secondary infections.

Dengue Outbreak and Response - Puerto Rico, 2024

Dengue, a mosquitoborne viral infection, is a public health threat in Puerto Rico, where multiple dengue virus (DENV) serotypes circulate. Dengue causes an acute febrile illness that can progress to severe disease or death. The last outbreak declared by the Puerto Rico Department of Health occurred during 2013. In January 2024, the number of dengue cases in Puerto Rico surpassed the epidemic threshold and remained elevated, prompting the Puerto Rico Department of Health to declare a public health emergency in March 2024. In collaboration with CDC, a dengue outbreak response was initiated to monitor the outbreak and implement vector-control measures alongside public health campaigns to raise awareness about increasing dengue case numbers and strategies to prevent mosquito bites. During 2024, a total of 6,291 confirmed dengue cases were reported; the highest numbers of cases were reported in the municipalities of San Juan (1,200; 17.3%), Carolina (354; 5.1%), and Rincón (252; 3.6%). DENV serotype 3 predominated, accounting for 59.2% of cases with known serotype. Approximately one half of ill patients (52.3%) required hospitalization, with the highest percentages of hospitalizations (33.9%) and severe dengue cases (28.4%) occurring among persons aged 10-19 years. Overall, severe dengue was identified in 4.2% of cases, with 11 reported fatalities (0.2%). Transmission remains elevated in multiple regions, underscoring the need for tailored public health measures, including vaccination among eligible populations, vector management, community outreach, and provider education to facilitate improved outcomes. To reduce the risk for mosquito bites, residents of and visitors to Puerto Rico should consider using repellents, wearing protective clothing, and staying in places with door and window screens.

Comprehensive immune profiling of dengue and chikungunya viral responses using a novel miniaturized automated whole blood cellular analysis system and mass cytometry in a pediatric cohort in Msambweni, Kenya

Chikungunya (CHIKV) and dengue (DENV) are mosquito-borne viruses that cause severe epidemics, often in remote regions. A limitation to our understanding of these pathogens is the difficulty of performing assays of the cellular immune response. To fill this gap, we developed a novel miniaturized automated system capable of processing 250 μl of whole blood for high-throughput cellular analysis. In a field study with a pediatric cohort in Msambweni, Kenya, known for previous exposure to CHIKV and/or DENV, we processed 133 whole blood samples using our system under three conditions: no stimulation, and stimulation with CHIKV or DENV peptide pools. These samples underwent CyTOF or flow cytometry analysis to evaluate virus-specific memory T cell responses and phenotypes. CyTOF analysis of 81 participant samples revealed significant cytokine responses to CHIKV and DENV, particularly IFNγ (P < 0.01 and P < 0.0001, respectively) and TNF-α (P < 0.0001) by γδ T cells. Additionally, a significant TNF-α response was observed in the CD8+ TEMRA memory subset to DENV, albeit to a lesser degree than in γδ T cells. To confirm our CyTOF findings, we employed flow cytometry on the remaining 40 samples using a targeted panel, validating significant TNF-α (P < 0.0001 and P < 0.01) and IFN-γ (P < 0.05) responses by γδ T cells to CHIKV and DENV, respectively. Our study demonstrates that our innovative automated system enables detailed assessment of immune function, particularly beneficial in pediatric populations and resource-limited settings with limited sample volumes. This approach holds promise for advancing our understanding of cellular immune responses to various viral and infectious diseases.

Next-Generation Point-of-Care Diagnostics: Silver Nanoparticle-Enhanced 3D-Printed Multiplex Electrochemical Biosensor for Detecting Dengue and Chikungunya Viruses

In recent years, the increasing prevalence of viral infections such as dengue (DENV) and chikungunya (CHIKV) has emphasized the vital need for new diagnostic techniques that are not only quick and inexpensive but also suitable for point-of-care and home usage. Existing diagnostic procedures, while useful, sometimes have limits in terms of speed, mobility, and price, particularly in resource-constrained environments and during epidemics. To address these issues, this study proposes a novel technique that combines 3D printing technology with electrochemical biosensors to provide a highly sensitive, user-friendly, and customizable diagnostic platform. This study focuses on a unique 3D-printed electrode cassette made with fused deposition modeling technology, which ensures strong structural alignment and improved performance under a variety of environmental conditions. When combined with paper-based electrodes loaded with silver nanoparticles, the platform dramatically enhances the detection sensitivity and reliability. The biosensor uses cyclic voltammetry and electrochemical impedance spectroscopy to detect DENV and CHIKV antigens within a linear range of 1 × 102 to 1 × 106 ng/mL. Results were delivered in 20 s and stable for 30 days. The device's performance was verified by testing with blood serum samples containing both DENV and CHIKV antigens, demonstrating its capacity to properly identify coinfections. This novel diagnostic tool represents a huge step forward in accessible and efficient healthcare solutions, bridging important gaps in the global battle against arboviral infections.

Recent advances in the control of dengue fever using herbal and synthetic drugs

Dengue virus represents a global public health threat, being prevalent in tropical and subtropical regions, with an increasing geographical distribution and rising incidence worldwide. This mosquito-borne viral agent causes a wide range of clinical manifestations, from mild febrile illness to severe cases and potentially fatal outcomes due to hemorrhage and shock syndrome. The etiological agent, dengue virus (DENV), has four distinct serotypes, each capable of inducing severe clinical outcomes. The current therapeutic landscape remains limited, with management strategies mainly focused on supportive cares. However, recent advances in pharmaceutical research have yielded promising developments in anti-dengue drugs. Extensive investigations have been conducted on various synthetic compounds, including JNJ-1802, 1,4-pyran naphthoquinones, and arylnaphthalene lignan derivatives. Additionally, natural compounds derived from medicinal plants such as Hippophae rhamnoides, Azadirachta indica, and Cymbopogon citratus have demonstrated potential antiviral properties in both in vitro and in vivo studies, based on inhibition of DENV replication. However, none of these compounds are to date approved by the U.S. Food and Drug Administration (FDA). Although many vaccines have been recognized as candidates in various stages of clinical trials, only a limited number of these have demonstrated a protective efficacy against the infection. This aspect underscores the need for both highly effective immunization strategies and therapeutic interventions, whether derived from botanical sources or through synthetic manufacturing, that exhibit low adverse effects. This review examines innovative approaches to DENV prevention and treatment, encompassing both phytochemical and synthetic therapeutic strategies.

Stabilized dengue virus 2 envelope subunit vaccine redirects the neutralizing antibody response to all E-domains

The four-dengue virus (DENV) serotypes cause several hundred million infections annually. Several live-attenuated tetravalent dengue vaccines (LAVs) are at different stages of clinical testing and regulatory approval. A major hurdle faced by the two leading LAVs is uneven replication of vaccine serotypes stimulating a dominant response to one serotype at the expense of the other three, leading to the potential for vaccine antibody (Ab) enhanced more severe infections by wild type DENV serotypes that fail to replicate in the vaccine. Protein subunit vaccines are a promising alternative since antigen dosing can be precisely controlled. However, DENV envelope (E) protein subunit vaccines have not performed well to date, possibly due to differences between the monomeric structure of soluble E and the E homodimer of the viral surface. Previously, we have combined structure-guided computational and experimental approaches to design and produce DENV2 E antigens that are stable homodimers at 37°C and stimulate higher levels of neutralizing Abs (NAbs) than the WT E antigen in mice. The goal of this study was to evaluate if DENV2 E homodimers stimulate NAbs that target different epitopes on E protein compared to the WT E monomer. Using DENV4/2 chimeric viruses and Ab depletion methods, we mapped the WT E-elicited NAbs to simple epitopes on domain III of E. In contrast, the stable E homodimer stimulated a more complex response towards all three surface-exposed domains of the E protein. Our findings highlight the impact of DENV2 E oligomeric state on the quality and specificity of DENV NAbs, and the promise of DENV E homodimers as subunit vaccines.

Craft: A Machine Learning Approach to Dengue Subtyping

Motivation

The dengue virus poses a major global health threat, with nearly 390 million infections annually. A recently proposed hierarchical dengue nomenclature system enhances spatial resolution by defining major and minor lineages within genotypes, aiding efforts to track viral evolution. While current subtyping tools - Genome Detective, GLUE, and NextClade - rely on computationally intensive sequence alignment and phylogenetic inference, machine learning presents a promising alternative for achieving accurate and rapid classification.

Results

We present Craft (Chaos Random Forest), a machine learning framework for dengue subtyping. We demonstrate that Craft is capable of faster classification speeds while matching or surpassing the accuracy of existing tools. Craft achieves 99.5% accuracy on a hold-out test set and processes over 140 000 sequences per minute. Notably, Craft maintains remarkably high accuracy even when classifying sequence segments as short as 700 nucleotides.

Comparison on the quality of sterile Aedes aegypti mosquitoes produced by either radiation-based sterile insect technique or Wolbachia-induced incompatible insect technique

Novel and alternative vector control approaches using a sterile male-based release to suppress Aedes aegypti mosquito vectors have recently been tested in the field in many countries. These approaches included the sterile insect technique (SIT), incompatible insect technique (IIT), and a combination of both techniques. In this study, we conducted a series of experiments to compare the quality between radiation-based and Wolbachia-induced sterile males in terms of flight ability, sterility, mating competitiveness, survival rate, and longevity. Aedes aegypti mosquitoes irradiated at 50 Gy (SIT) and those trans-infected with wAlbB Wolbachia (IIT) were used for quality comparison. Our results showed that irradiated and Wolbachia trans-infected males were not significantly different in flight ability (p > 0.05) and both could induce sterility in wild-type females. In addition, although irradiation at 50 Gy or Wolbachia trans-infection reduced male mating competitiveness, combined irradiation and Wolbachia wAlbB trans-infection increased male competitiveness at the one-to-one ratio. Increasing the number of sterile males released could compensate for reduced competitiveness but it does not make them more competitive. Irradiation did not affect the survival and longevity of irradiated males, but it showed significant negative impacts on females (p < 0.05); while the opposite was observed in the case of Wolbachia infection, i.e., with significant increase in the survival rate of Wolbachia trans-infected males (p < 0.05), but both survival and longevity were reduced in Wolbachia trans-infected females with no significant impacts (p > 0.05). In conclusion, neither irradiation nor Wolbachia trans-infection significantly affected the quality of sterile males except their mating competitiveness; but this could compensate by increasing the number of sterile males released. Sterility could be induced by either 50 Gy irradiation or wAlbB trans-infection. Mating competitiveness results showed that a higher number of sterile males produced by irradiation need to be released in comparison to those produced by Wolbachia trans-infection. Our results should be useful for planning SIT, IIT, or a combination for Ae. aegypti vector control.

Dengue: epidemiology, diagnosis methods, treatment options, and prevention strategies

Dengue is an arboviral disease caused by dengue virus, which is mostly found in tropical regions, and the number of human cases has increased dramatically since 2000, with 5.2 million cases reported in 2019, according to WHO reports, 70% of which were in Southeast Asia, the Western Pacific, and Asia. Dengue infection can result in a wide range of clinical manifestations, ranging from fever to severe dengue shock syndrome, which can be fatal, particularly in those with secondary dengue. This review of the aetiology of dengue fever examines the complex interactions between the virus and the immune system and the interaction between viral and host factors and also covers outbreaks, the severity of disease caused by different serotypes, and methods for diagnosis of dengue, such as serological tests, nucleic acid amplification tests, and ELISA assays for detecting the NS1 antigen. Current treatment options and prevention strategies, including vector control measures, environmental interventions, and insect repellents are also discussed. This review highlights the challenges involved in developing a dengue vaccine, which is complicated by the need for an efficient and balanced immune response against all genotypes of the four serotypes.

Elevated Plasma Angiopoietin-like 4 Protein Levels in Adult Patients with Dengue

Dengue virus infection can cause severe complications due to vascular leakage. Angiopoietin-like protein 4 (ANGPTL4) regulates vascular permeability, but its role in dengue pathogenesis is unclear. This study investigated the association between plasma ANGPTL4 levels and dengue severity in Singapore adults. Plasma samples from 48 dengue patients (24 severe and 24 non-severe) during acute and convalescent phases were selected from the prospective COhort study on progression of DENgue severity in Singapore adults (CODEN) cohort. The CODEN was conducted at the National Centre for Infectious Diseases, Tan Tock Seng Hospital, from June 2016 to January 2020. ANGPTL4 levels were measured and compared to 152 healthy controls. Logistic regression assessed the relationship between plasma ANGPTL4 concentrations and disease severity. There were no statistically significant differences in ANGPTL4 levels between severe and non-severe dengue patients during acute (677.4 vs. 909.1 pg/mL, p = 0.4) or convalescent phases (793.7 vs. 565.6 pg/mL, p = 0.96). Plasma ANGPTL4 levels were significantly elevated during acute dengue (4634.3 pg/mL) versus healthy controls (907.4 pg/mL), declining during convalescence. Compared to the lowest tertile, the adjusted odds ratios for severe dengue were 0.36 (95%CI: 0.08-1.65, p = 0.190) for medium tertile and 0.57 (95%CI: 0.13-2.49, p = 0.456) for high tertile. Among patients with high ANGPTL4 levels (>5000 pg/mL), 36.4% developed severe complications, including significant plasma leakage. Plasma ANGPTL4 levels were significantly higher in dengue patients than controls, suggesting its potential as a biomarker, which warrants future detailed investigations. Larger prospective studies with serial sampling, including pediatric populations, may clarify the role of ANGPTL4 in severe dengue.

Comparison of Predictive Models for Severe Dengue: Logistic Regression, Classification Tree, and the Structural Equation Model

BACKGROUND

This study aimed to compare the predictive performance of 3 statistical models-logistic regression, classification tree, and structural equation model (SEM)-in predicting severe dengue illness.

METHODS

We adopted a modified classification of dengue illness severity based on the World Health Organization's 1997 guideline. We constructed predictive models using demographic factors and laboratory indicators on the day of fever occurrence, with data from 2 hospital cohorts in Thailand (257 Thai children). Different predictive models for each category of severe dengue illness were developed employing logistic regression, classification tree, and SEM. The model's discrimination abilties were analyzed with external validation data sets from 55 and 700 patients not used in model development.

RESULTS

From external validation based on predictors on the day of presentation to the hospital, the area under the receiver operating characteristic curve was from 0.65 to 0.84 for the regression models from 0.73 to 0.85 for SEMs. Classification tree models showed good results of sensitivity (0.95 to 0.99) but poor specificity (0.10 to 0.44).

CONCLUSIONS

Our study showed that SEM is comparable to logistic regression or classification tree, which was widely used for predicting severe forms of dengue.

Detection of viral antigen and inflammatory mediators in fatal pediatric dengue: a study on lung immunopathogenesis

Introduction

The dengue virus (DENV) is the etiological agent that causes dengue fever illness, an arbovirus with a major endemic potential that has become increasingly prevalent in Brazil and has already been associated with fatal cases in children. DENV has tropism for several organs, including lungs causing pulmonary complications. The aim of this article was to evaluate the inflammatory and histopathological profile of the lung tissue of three fatal cases of children infected with DENV, which represents a group more susceptible to fatality due to its incomplete development.

Methods

Histopathological analysis was carried out using Hematoxylin and Eosin staining and special stains. While the characterization of the inflammatory response and cellular expression was done by marking the viral protein, macrophages, lymphocytes and pro-inflammatory cytokines.

Results and discussion

The results confirm that vascular dysfunctions such as hemorrhage, vascular congestion and edema associated with a mononuclear infiltrate were observed in all three cases. In addition, the presence of viral replication and increased expression of inflammatory markers were also observed. Such findings contribute to the study and description of dengue, especially its effects on lung tissue.

miR-11903a modulates CLIPB9-mediated pathogen defense and longevity in Aedes aegypti

Arthropod melanization is a crucial defense mechanism mediated by a complex cascade of CLIP domain serine proteases (CLIPs). In this study, it was confirmed that microRNA-11903a (miR-11903a) targets Aedes-CLIPB9 (AeCLIPB9) by bioinformatics prediction and dual-luciferase reporter assays. Following intrathoracic injection of miR-11903a agomir and antagomir, Real-time quantitative polymerase chain reaction confirmed that AeCLIPB9 is negatively regulated by miR-11903a. Spatiotemporal expression analysis revealed that miR-11903a is most abundant in 4th instar larvae, followed by pupae and adults, and highly expressed in the wings, head, and midgut of female adults. Following pathogen infection, AeCLIPB9 and miR-11903a exhibited opposite expression trends, indicating their potential roles in mosquito innate immunity. To further investigate the relationship between AeCLIPB9 and miR-11903a, double-strand CLIPB9 was synthesized and RNA interference was performed. Seven-d survival assays revealed that both AeCLIPB9 and miR-11903a were crucial immune factors in fighting pathogens. Finally, longevity assays demonstrated that miR-11903a influenced mosquito lifespan.

Machine learning for predicting severe dengue in Puerto Rico

BACKGROUND

Distinguishing between non-severe and severe dengue is crucial for timely intervention and reducing morbidity and mortality. World Health Organization (WHO)-recommended warning signs offer a practical approach for clinicians but have limited sensitivity and specificity. This study aims to evaluate machine learning (ML) model performance compared to WHO-recommended warning signs in predicting severe dengue among laboratory-confirmed cases in Puerto Rico.

METHODS

We analyzed data from Puerto Rico's Sentinel Enhanced Dengue Surveillance System (May 2012-August 2024), using 40 clinical, demographic, and laboratory variables. Nine ML models, including Decision Trees, K-Nearest Neighbors, Naïve Bayes, Support Vector Machines, Artificial Neural Networks, AdaBoost, CatBoost, LightGBM, and XGBoost, were trained using fivefold cross-validation and evaluated with area under the receiver operating characteristic curve (AUC-ROC), sensitivity, and specificity. A subanalysis excluded hemoconcentration and leukopenia to assess performance in resource-limited settings. An AUC-ROC value of 0.5 indicates no discriminative power, while values closer to 1.0 reflect better performance.

RESULTS

Among the 1708 laboratory-confirmed dengue cases, 24.3% were classified as severe. Gradient boosting algorithms achieved the highest predictive performance, with an AUC-ROC of 97.1% (95% CI: 96.0-98.3%) for CatBoost using the full 40-variable feature set. Feature importance analysis identified hemoconcentration (≥ 20% increase during illness or ≥ 20% above baseline for age and sex), leukopenia (white blood cell count < 4000/mm3), and timing of presentation at 4-6 days post-symptom onset as key predictors. When excluding hemoconcentration and leukopenia, the CatBoost AUC-ROC was 96.7% (95% CI: 95.5-98.0%), demonstrating minimal reduction in performance. Individual warning signs like abdominal pain and restlessness had sensitivities of 79.0% and 64.6%, but lower specificities of 48.4% and 59.1%, respectively. Combining ≥ 3 warning signs improved specificity (80.9%) while maintaining moderate sensitivity (78.6%), resulting in an AUC-ROC of 74.0%.

CONCLUSIONS

ML models, especially gradient boosting algorithms, outperformed traditional warning signs in predicting severe dengue. Integrating these models into clinical decision-support tools could help clinicians better identify high-risk patients, guiding timely interventions like hospitalization, closer monitoring, or the administration of intravenous fluids. The subanalysis excluding hemoconcentration confirmed the models' applicability in resource-limited settings, where access to laboratory data may be limited.

Sub-Inner Limiting Membrane Hemorrhage Secondary to Dengue Fever Treated With Nd: YAG Laser Hyaloidotomy

Purpose: To report a patient with a sub-inner limiting membrane (ILM) hemorrhage secondary to dengue fever treated with neodymium:YAG (Nd:YAG) laser hyaloidotomy. Methods: A single case was evaluated. Results: A 41-year-old man presented with sudden vision loss in the left eye 10 days after being diagnosed with dengue fever. Fundoscopy showed a sub-ILM macular hemorrhage in the left eye. Out of concern for retinal toxicity and to quickly restore visual acuity (VA), an Nd:YAG laser hyaloidotomy was performed. One month after the procedure, the VA in the left eye improved from 0.1 to 1.0 with complete resolution of the hemorrhage. Conclusions: Given the substantial increase in cases of dengue fever and its possible ophthalmologic involvement, this case highlights the importance of an ophthalmologic examination with fundoscopy in patients with a sub-ILM hemorrhage and the possibility of treatment with an Nd:YAG laser.

[The effects of climate change on the emergence of dengue]

In recent decades, dengue has become a global issue due to its rapid spread and significant public health impact. Climate change is recognized as a key factor in the geographical spread of dengue and its vectors. Climate change affects dengue transmission through changes in temperature and precipitation, which affect both vectors and arboviruses. Climate change can also disrupt human migration patterns facilitating the spread of the virus and the invasion of vectors into new regions. Understanding the impact of climate change on dengue and its vectors is essential for developing strategies to prevent and control the disease. Appropriate mosquito control strategies, enhanced epidemiological surveillance and tailored public health systems are needed to mitigate the increasing burden of dengue in the context of climate change.

Exploring potential application of anti-dengue NS1 human polyclonal antibodies for detection of dengue virus infection

Dengue, a vector-borne disease, affects nearly 400 million people annually. Although commercially available dengue NS1 antigen-based ELISA kits are simple and rapid, they are expensive as monoclonal antibodies are used in these tests, and also, they have short expiry dates. As an alternative, the polyclonal antibodies generated against dengue NS1 antigen from the individuals who recovered from the dengue infection (human polyclonal antibodies against dengue; HuPA-D) can be explored for the detection of NS1 antigen in the dengue virus (DENV) infected patients' sera. In this study, blood samples were collected from the dengue-recovered patients after obtaining the IHEC approval. The anti-NS1 HuPA-D (IgG) was purified using NAb™ Spin Column kit and tested on SDS-PAGE. HuPA-D ELISA was developed to test the sensitivity and specificity of the antibodies using the recombinant NS1 antigens of dengue serotypes and flaviviruses. Further, the HuPA-D were used to detect the sera of the dengue patients. The assay was found to be sensitive to detect all the serotypes of recombinant dengue NS1 antigen and also NS1 antigen from the sera of DENV infected patients.

Ambient temperature and dengue hospitalization in Brazil: A 10-year period case time series analysis

Background

Dengue has an increased worldwide epidemic potential with the global rising temperature due to climate change. Heat and rainfall are known to influence seasonal patterns of dengue transmission over the course of weeks to months. However, there is a gap in knowledge about the short-term effect of heat on dengue severity. We aimed to quantify the effect of ambient temperature on dengue hospitalization risk in Brazil.

Methods

Daily dengue hospitalization counts and average daily ambient temperature from 2010 to 2019 were analyzed from Brazil. We applied the case time series design combined with a distributed lag nonlinear model framework to estimate relative risk (RR) estimates for dose-response and lag-response structures for the association of temperature and dengue hospitalization. We estimate the overall dengue hospitalization RR for the whole country as well as for each of the five macroregions.

Results

A total of 579,703 hospital admissions due to dengue occurred between 2010 and 2019. We observed a positive association between high temperatures and a high risk of hospitalization across the country. Under extreme heat (95th percentile of temperature), the RR was 3.47 (95% confidence interval: 2.88, 4.19) compared with minimum hospitalization risk. This association was mainly driven by an immediate effect of heat (lag 0) and was similar for the Northeast, Center-West, Southeast, and South regions, but unclear for the North. The risk was of greater magnitude among females and those aged ≥65 years.

Conclusion

Short-term high temperatures are associated with an increase in the risk of hospitalization by dengue.

The Impact of Administrative Districts and Urban Landscape on the Dispersal of Aedes aegypti via Genetic Differentiation

Mosquito-borne diseases affect millions and cause numerous deaths annually. Effective vector control, which hinges on understanding their dispersal, is vital for reducing infection rates. Given the variability in study results, likely due to environmental and human factors, gathering local dispersal data is critical for targeted disease control. To analyse the spread and differentiation of Aedes aegypti in southern Taiwan, we established a dengue vector monitoring network in Southern Taiwan's cities. This network employed GPS-equipped ovitraps to gather eggs that were subsequently hatched in the laboratory and genotyped using genome-wide SNP markers. From 168 individuals, we identified 757,238 SNPs for detailed analysis. The estimated effective dispersal distance was 154 m (95% CI: 126-180 m), consistent with prior mark-release-recapture (MRR) estimates. We discovered that geographic isolation significantly influences genetic differentiation at larger scales, such as between cities, whereas its correlation with genetic distances is considerably weaker at smaller scales, like within cities. This is likely due to the urban landscape in Taiwan, characterised by narrow roads and densely packed buildings, which facilitates extensive dispersal of Ae. aegypti. In evaluating potential barriers to Ae. aegypti dispersal, we found that roads had no significant impact, whereas administrative districts accounted for 4.8% of the population differentiation (p < 10-4). Surprisingly, this variation aligns with the effects of district-specific mosquito control measures implemented at the municipal level. These findings highlight the complex interplay between urban landscapes, administrative measures and Ae. aegypti dispersal, emphasising the need for implementing targeted control strategies that consider these local dynamics.

Temporal shifts in dengue epidemic in Guangdong Province before and during the COVID-19 pandemic: a Bayesian model study from 2012 to 2022

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, the implementation of public health intervention measures have reshaped the transmission patterns of other infectious diseases. We aimed to analyze the epidemiological characteristics of dengue in Guangdong Province, China, and to investigate the temporal shifts in dengue epidemic in Guangdong Province during the COVID-19 pandemic.

METHODS

Based on the data of dengue reported cases, meteorological factors, and mosquito vector density in Guangdong Province from 2012 to 2022, wavelet analysis was applied to investigate the relationship between the dengue incidence in Southeast Asian (SEA) countries and the local dengue incidence in Guangdong Province. We constructed the dengue importation risk index to assess the monthly risk of dengue importation. Based on the counterfactual framework, we constructed the Bayesian structural time series (BSTS) model to capture the epidemic trends of dengue.

RESULTS

Wavelet analysis showed that the local dengue incidence in Guangdong Province was in phase correlation with the dengue incidence of the prior month in relative SEA countries. The dengue importation risk index showed an increasing trend from 2012 to 2019, then decreased to a low level during the COVID-19 pandemic. From 2020 to 2022, the average annual number of reported imported cases and local cases of dengue in Guangdong Province were 26 and 2, respectively, with a decrease of 95.62% and 99.94% compared to the average during 2017-2019 (594 imported cases and 3,118 local cases). According to BSTS model estimates, 6557 local dengue cases may have been reduced in Guangdong Province from 2020 to 2022, with a relative reduction of 99.91% (95%CI: 98.85-99.99%).

CONCLUSION

The incidence of dengue in Guangdong notably declined from 2020 to 2022, which may be related to the co-benefits of COVID-19 intervention measures and the intensified interventions against dengue during that period. Furthermore, our findings further supported that dengue is not currently endemic in Guangdong.

Elevated developmental temperatures below the lethal limit reduce Aedes aegypti fertility

Aedes aegypti mosquitoes are the principal vectors of dengue and continue to pose a threat to human health, with ongoing urbanization, climate change and trade all impacting the distribution and abundance of this species. Hot periods are becoming increasingly common and their impacts on insect mortality have been well established, but they may have even greater impacts on insect fertility. In this study, we investigated the impacts of high temperatures on Ae. aegypti fertility both within and across generations. Mosquitoes developing under elevated temperatures exhibited higher critical thermal maxima (CTmax), reflecting developmental acclimation, but their fertility declined with increasing developmental temperature. In females, elevated developmental temperatures decreased fecundity while in males it tended to decrease the proportion of eggs that hatched and the proportion of individuals producing viable offspring. Rearing both sexes at 35°C increased fecundity in the subsequent generation but effects of elevated temperatures persisted across gonotrophic cycles within the same generation. Moreover, exposure of adults to 35°C further decreased fertility beyond the effects of developmental temperature alone. These findings highlight sub-lethal impacts of elevated temperatures on Ae. aegypti fertility and plastic responses to thermal stress within and across generations. This has significant implications for predicting the distribution and abundance of mosquito populations thriving in increasingly warmer environments.

Hijacking of plasminogen by dengue virus: The kringle-4 and -5 domains of plasminogen binds synergistically to the domain I of envelope protein

Dengue fever is a serious health issue, particularly in tropical countries like Singapore. We have previously found that dengue virus (DENV) recruits human plasmin in blood meal to enhance the permeability of the mosquito midgut for infection. Here, using biolayer interferometry, we found that neither kringle-4 nor kringle-5 plasmin domains alone binds well to dengue virus. However, the domains together lead to a synergistic effect, with both kringle-4 and -5 domains required and sufficient for binding. Site-directed mutagenesis experiments showed that the N-terminal and C-terminal aspartic acid residues in the "DXD" acidic motifs of the kringle-4 and -5 domains likely have different roles when engaged with DENV. Hydrogen deuterium exchange mass spectrometry experiments on the plasmin:DENV complex led to the identification of two Lys-containing regions on domain I of the E-protein of DENV that are buried by plasmin and could be potential plasmin binding sites. These findings contradict with published literature that domain III of the DENV E-protein interacts with the kringle-1-3 domains of plasmin. We provide a plausible explanation for the observed discrepancies.

Comparative monocyte and T cell responses in DENV-exposed subjects from South-East Asia and DENV-naïve residents in Taiwan

BACKGROUND/PURPOSE(S)

Dengue virus (DENV) is one of the most troublesome mosquito-borne infectious viruses in tropical and subtropical zones. People with secondary/multiple DENV infections are at an increased risk of developing severe dengue. Both monocytes and T cells are known to play important roles in the immune response against DENV. However, the function of monocytes and T cells in individuals with potentially multiple exposures to DENV is rarely reported.

METHOD

In the present study, we performed a functional analysis of monocytes and T cells from people with previous DENV infection and DENV-naïve people that stimulated with DENV2 ex vivo.

RESULTS

Our preliminary analysis indicated that the response of monocytes and T cells to DENV2 restimulation was comparable between DENV-exposed and DENV-naïve individuals. Furthermore, the cytokine expression profiles in monocytes from both naïve individuals and previously DENV-exposed subjects were similar after DENV2 stimulation. In addition, it was observed that the function of T cells was also equivalent when monocytes were present as antigen-presenting cells for dengue antigen, NS3, in terms of cell proliferation, interferon-gamma (IFNγ) secretion, and memory response.

CONCLUSIONS

Based on the results, it was observed that previously DENV-exposed monocytes and T cells seemed to be anergic during DENV reinfection. However, whether the impaired response of monocytes and T cells against DENV in people with a history of previous DENV infection leads to severe dengue upon secondary infection in endemic areas requires further investigation.

Development and optimization of an mRNA-vectored single-chain IgA1 isotype monoclonal antibody with potential to treat or prevent dengue virus infection

Dengue virus (DENV) is a rapidly expanding infectious disease threat that causes an estimated 100 million symptomatic infections every year. A barrier to preventing DENV infections with traditional vaccines or prophylactic monoclonal antibody (mAb) therapies is the phenomenon of Antibody-Dependent Enhancement (ADE), wherein sub-neutralizing levels of DENV-specific IgG antibodies can enhance infection and pathogenesis rather than providing protection from disease. Fortunately, IgG is not the only antibody isotype capable of binding and neutralizing DENV, as DENV-specific IgA1 isotype mAbs can bind and neutralize DENV while without exhibiting any ADE activity. However, the development of IgA1-based mAb therapies is currently hindered by inefficient in vitro expression systems and the lack of saleable purification platforms. Accordingly, alternative delivery modalities are required to realize the therapeutic potential of IgA-based infectious-disease therapies. In this study we describe the development and optimization of a DENV-specific single-chain IgA construct that retains the desirable biological properties of the parental IgA mAb yet is compatible with efficient in vivo delivery with a novel/liver-tropic lipid nanoparticle. We propose that this platform is uniquely and exceptionally well suited for preventing and/or treating DENV infections and may have broad applicability in the greater infectious disease space in situations where the use of IgG isotype mAbs may be counterindicated.

New insights into gold nanoparticles in virology: A review of their applications in the prevention, detection, and treatment of viral infections

Viral infections have led to the deaths of millions worldwide and come with significant economic and social burdens. Emerging viral infections, as witnessed with coronavirus disease 2019 (COVID-19), can profoundly affect all aspects of human life, highlighting the imperative need to develop diagnostic, therapeutic, and effective control strategies in response. Numerous studies highlight the diverse applications of nanoparticles in diagnosing, controlling, preventing, and treating viral infections. Due to favorable and flexible physicochemical properties, small size, immunogenicity, biocompatibility, high surface-to-volume ratio, and the ability to combine with antiviral agents, gold nanoparticles (AuNPs) have shown great potential in the fight against viruses. The physical and chemical properties, the adjustability of characteristics based on the type of application, the ability to cross the blood-brain barrier, the ability to infiltrate cells such as phagocytic and dendritic cells, and compatibility for complexing with various compounds, among other features, transform AuNPs into a suitable tool for combating and addressing pathogenic viral agents through multiple applications. In recent years, AuNPs have been employed in various applications to fight viral infections. However, a comprehensive review article on the applications of AuNPs against viral infections has yet to be available. Given their versatility, AuNPs present an appealing option to address various gaps in combating viral infections. Hence, this review explores the attributes, antiviral properties, contributions to drug delivery, vaccine development, and diagnostic uses of AuNPs.

SAM-dPCR: Accurate and Generalist Nuclei Acid Quantification Leveraging the Zero-Shot Segment Anything Model

Digital PCR (dPCR) has transformed nucleic acid diagnostics by enabling the absolute quantification of rare mutations and target sequences. However, traditional dPCR detection methods, such as those involving flow cytometry and fluorescence imaging, may face challenges due to high costs, complexity, limited accuracy, and slow processing speeds. In this study, SAM-dPCR is introduced, a training-free open-source bioanalysis paradigm that offers swift and precise absolute quantification of biological samples. SAM-dPCR leverages the robustness of the zero-shot Segment Anything Model (SAM) to achieve rapid processing times (<4 seconds) with an accuracy exceeding 97.10%. This method has been extensively validated across diverse samples and reactor morphologies, demonstrating its broad applicability. Utilizing standard laboratory fluorescence microscopes, SAM-dPCR can measure nucleic acid template concentrations ranging from 0.154 copies µL-1 to 1.295 × 103 copies µL-1 for droplet dPCR and 0.160 × 103 to 3.629 × 103 copies µL-1 for microwell dPCR. Experimental validation shows a strong linear relationship (r2 > 0.96) between expected and determined sample concentrations. SAM-dPCR offers high accuracy, accessibility, and the ability to address bioanalytical needs in resource-limited settings, as it does not rely on hand-crafted "ground truth" data.

PCSK9 in metabolism and diseases

PCSK9 is a serine protease that regulates plasma levels of low-density lipoprotein (LDL) and cholesterol by mediating the endolysosomal degradation of LDL receptor (LDLR) in the liver. When PCSK9 functions unchecked, it leads to increased degradation of LDLR, resulting in elevated circulatory levels of LDL and cholesterol. This dysregulation contributes to lipid and cholesterol metabolism abnormalities, foam cell formation, and the development of various diseases, including cardiovascular disease (CVD), viral infections, cancer, and sepsis. Emerging clinical and experimental evidence highlights an imperative role for PCSK9 in metabolic anomalies such as hypercholesterolemia and hyperlipidemia, as well as inflammation, and disturbances in mitochondrial homeostasis. Moreover, metabolic hormones - including insulin, glucagon, adipokines, natriuretic peptides, and sex steroids - regulate the expression and circulatory levels of PCSK9, thus influencing cardiovascular and metabolic functions. In this comprehensive review, we aim to elucidate the regulatory role of PCSK9 in lipid and cholesterol metabolism, pathophysiology of diseases such as CVD, infections, cancer, and sepsis, as well as its pharmaceutical and non-pharmaceutical targeting for therapeutic management of these conditions.

High correlation between detection of dengue IgG from dried blood spots and serum using an indirect IgG ELISA assay: A validation study in Fortaleza, Brazil

BACKGROUND

Dengue virus (DENV) seroprevalence studies often rely on Enzyme-Linked Immunosorbent Assay (ELISA) testing of serum samples, but ELISA testing of dried blood spot (DBS) samples offer several advantages for field-based research in resource-limited settings. However, DBS' limited sample volume can be challenging for test sensitivity, requiring validation studies with standard methods (e.g., analysis of serum through ELISAs or Plaque Reduction Neutralization Tests (PRNTs)). In preparation for a large cluster randomized controlled trial, we conducted a pilot study in 2019 to validate the use of DBS compared to serum samples for DENV IgG testing. We aimed to identify the optimal DBS dilution for IgG detection and to estimate the correlation, magnitude of agreement, and sensitivity and specificity of IgG detection in DBS versus serum samples.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted this pilot validation study among 119 healthy participants in Fortaleza, Brazil to evaluate and optimize the detection of DENV IgG from DBS compared to serum. Each participant provided paired DBS and venous blood samples, which were evaluated for DENV IgG using the Panbio Dengue IgG indirect ELISA. DBS elution diluted 1:4 was optimal compared with serum results, with high correlation (r= 0.98) and near-perfect agreement (kappa = 0.95). At this dilution, DBS had a sensitivity of 100%, a specificity of 92.3%, a 97.9% positive predictive value, and a 100% negative predictive value compared with serum.

CONCLUSIONS/SIGNIFICANCE

These results validate using DBS instead of serum for detection of prior dengue infection among similar populations in endemic regions, without sacrificing test sensitivity and specificity. The validity of using DBS for ELISA to detect prior dengue infection could have important implications for field-based research. A limitation to this study was that the potential for misclassification due to cross-reactivity (e.g., with Zika virus, Yellow Fever vaccine) was not assessed.

Long non-coding RNAs as promising targets for controlling disease vector mosquitoes

Hematophagous female mosquitoes are important vectors of numerous devastating human diseases, posing a major public health threat. Effective prevention and control of mosquito-borne diseases rely considerably on progress in understanding the molecular mechanisms of various life activities, and accordingly, the molecules that regulate the various life activities of mosquitoes are potential targets for implementing future vector control strategies. Many long non-coding RNAs (lncRNAs) have been identified in mosquitoes and significant progress has been made in determining their functions. Here, we present a comprehensive overview of the research advances on mosquito lncRNAs, including their molecular identification, function, and interaction with other non-coding RNAs, as well as their synergistic regulatory roles in mosquito life activities. We also highlight the potential roles of competitive endogenous RNAs in mosquito growth and development, as well as in insecticide resistance and virus-host interactions. Insights into the biological functions and mechanisms of lncRNAs in mosquito life activities, viral replication, pathogenesis, and transmission will contribute to the development of novel drugs and safe vaccines.

Prevalence of Emerging Arboviral Infections: A Tertiary Care Hospital-Based Study from Kashmir, Northern India

Background: Arboviruses are becoming a global public health menace. The common diseases worldwide caused by arboviruses are dengue, chikungunya, and Zika. This study aims to determine the prevalence of these three arboviral infections in patients with acute febrile illness at a tertiary care hospital in Kashmir, North India. Materials and Methods: A total of 812 blood samples were collected and tested for anti-dengue, anti-chikungunya immunoglobulin M (IgM), and dengue nonstructural protein 1 antigen by enzyme linked immunosorbent assay. Molecular testing of these samples was also done to detect dengue, chikungunya, and Zika viruses by using the CDC Trioplex real-time PCR assay. Results: The prevalence of diseases found among the studied patients was dengue 105/812 (12.93%) followed by chikungunya 17/812 (2.09%), and 3 cases (0.37%) were positive for both dengue and chikungunya; however, no case of Zika was detected. Interestingly, we found that only individuals that had a history of travel to different destinations within the country were positive for these viruses. Most affected cases were males 105/812 (12.93%) compared with females 20/812 (2.46%). Dengue serotyping results indicate that Dengue virus-1 was the most commonly found serotype. The most common symptoms in patients positive for dengue and chikungunya were fever, intense fatigue, myalgia, arthralgia, retro-orbital pain, anorexia, conjunctivitis, and skin rash. Conclusion: This study showed that dengue, chikungunya, and Zika viruses are not prevalent in the indigenous population of Kashmir. However, screening for these agents is required in people who have recently traveled outside Kashmir and have symptoms of acute febrile illness.

The V410L kdr allele in the VGSC confers higher levels of field resistance to permethrin in urban mosquito populations of Aedes aegypti (L.)

BACKGROUND

Females of Aedes aegypti transmit emerging arboviruses including Zika, dengue, yellow fever, and chikungunya. Control of these adult mosquitoes heavily relies on synthetic insecticides, including pyrethroids. However, insecticide resistance development in populations poses a significant challenge to vector control, particularly from knockdown resistance (kdr) mutations in the voltage-gated sodium channel (VGSC), the target of pyrethroids. This study investigated the field efficacy of Permanone, a pyrethroid-based insecticide, against Ae. aegypti by assessing the impact of three common kdr mutations (V410L, V1016I, F1534C) on mosquito survival under a real operational mosquito control scenario, by quantifying the pesticide delivered in the field.

RESULTS

Field cage tests (FCTs) were conducted while conducting a realistic mosquito control application. Female mosquitoes from six operational areas from Harris County, TX, USA were exposed to Permanone delivered with a handheld sprayer. Permanone deposited near the cages was estimated from aluminum boats placed in the field during FCTs using gas chromatography-mass spectrometry (GC-MS). Mortality rates were recorded, and individual mosquitoes were genotyped for kdr mutations. A probit regression model was used to analyze the factors influencing mosquito survivorship. As the distance from the application source route increased, the amount of Permanone deposited decreased, resulting in higher survivorship frequency of Ae. aegypti females with the triple-resistant kdr genotype (LL/II/CC). The L allele at the 410-site significantly contributed to an increased resistance level when co-occurring with other kdr mutations.

CONCLUSION

This study linked the survival probabilities of mosquitoes with different kdr genotypes, and the amount of pesticide they received in the field. Pesticide quantification, control efficacy results and genotyping allowed us to empirically determine the impact of genotypic resistance on vector control in the field. © 2024 Society of Chemical Industry.

Early circulating biomarkers to predict plasma leakage in dengue fever

BACKGROUND

Dengue, a mosquito-borne viral infection, poses a rapidly growing burden, particularly in low- and middle-income countries. Without early identification of patients at risk of severe outcomes (dengue haemorrhagic fever, severe dengue, and plasma leakage- the latter typically occurring on days 5-7 of illness), untriaged admissions lead to hospital overcrowding and suboptimal care.

METHODS

This nested case-control study compared early-stage plasma samples (within the first 96 hours of fever) from dengue patients with and without plasma leakage. Thirty-four potential biomarkers, selected through systematic review, were tested on a multiplex bead-based immunoassay platform. Subgroup analysis stratified patients by primary or secondary dengue infection.

FINDINGS

A total of 228 patient samples (114 had plasma leakage) were tested. Elevated Vascular cell adhesion molecule-1 (OR:3.289, 95% CI: 1.090-9.926, p<0.05), and Interleukin 33 receptor levels (OR: 2.677, 95% CI: 1.244-5.856, p<0.05) were associated with an increased risk of plasma leakage while eotaxin-1 was associated with a decreased risk (OR: 0.166, 95% CI: 0.057-0.483, p<0.05). When adjusted for prior dengue exposure, additional biomarkers (C-X-C motif chemokine 11, serum amyloid A) were also associated with plasma leakage.

INTERPRETATION

Plasma leakage in dengue, being more objectively measurable than other severe outcomes, offers a reliable endpoint for biomarker studies. Identifying biomarkers that predict plasma leakage strengthens the evidence base in dengue research. These biomarkers could improve clinical assessment and patient care in dengue cases.

Natural Compounds and Their Analogs as Antivirals Against Dengue Virus: A Review

Dengue virus (DENV) continues to pose a significant global health challenge, causing diseases such as dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. While efforts in vaccine development and antiviral drug discovery are ongoing, effective therapeutic options remain limited. In this review, we highlight natural compounds and the analogs that demonstrated antiviral activity against DENV in in vitro and in vivo studies. Specifically, these studies examine alkaloids, phenolic acids, phenols, flavonoids, terpenoids, and glycosides which have shown potential in inhibiting DENV entry, replication, and reducing the cytokine storm. By focusing on these bioactive compounds and the analogs, a comprehensive overview of their promising roles is provided to advance therapeutic strategies for combating DENV infection.

Arbovirus Epidemics as Global Health Imperative, Africa, 2023

Arboviruses represent a major cause of illness in Africa and have the potential to trigger widespread epidemics. We present data on arbovirus epidemics in Africa in 2023 and demonstrate the need for global public health authorities to intensify efforts in the surveillance and control of arbovirus diseases. Data were collected from the World Health Organization Weekly Bulletin on Outbreaks and Other Emergencies, Africa Centers for Disease Control and Prevention Weekly Event Based Surveillance Report, and other online sources. In 2023, a total of 7 arboviruses were responsible for 29 outbreaks across 25 countries in Africa, 22 of which occurred in West Africa; the outbreaks resulted in 19,569 confirmed cases and 820 deaths. Arbovirus epidemics in Africa pose a threat not only to public health within the continent but also globally, underscoring the urgent need for substantial investment in arbovirus surveillance, research, and preparedness capacities in Africa to prevent and respond to health crises effectively.

Unraveling potential gene biomarkers for dengue infection through RNA sequencing

Dengue virus hijacks host cell mechanisms and immune responses in order to replicate efficiently. The interaction between the host and the virus affects the host's gene expression, which remains largely unexplored. This pilot study aimed to profile the host transcriptome as a potential strategy for identifying specific biomarkers for dengue prediction and detection. High-throughput RNA sequencing (RNA-seq) was employed to generate host transcriptome profiles in 16 dengue patients and 10 healthy controls. Differentially expressed genes (DEGs) were identified in patients with severe dengue and those with dengue with warning signs compared to healthy individuals. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to elucidate the functions of upregulated and downregulated genes. Compared to healthy controls, 6466 genes were significantly differentially expressed (p < 0.05) in the dengue with warning signs group and 3082 genes in the severe dengue group, with over half being upregulated. The major KEGG pathways implicated included transport and catabolism (14.4%-16.3%), signal transduction (6.6%-7.3%), global and overview maps (6.7%-7.1%), viral diseases (4.6%-4.8%), and the immune system (4.4%-4.6%). Several genes exhibited consistent and significant upregulation across all dengue patients, regardless of severity: Interferon alpha inducible protein 27 (IFI27), Potassium Channel Tetramerization Domain Containing 14 (KCTD14), Syndecan 1 (SDC1), DCC netrin 1 receptor (DCC), Ubiquitin C-terminal hydrolase L1 (UCHL1), Marginal zone B and B1 cell-specific protein (MZB1), Nestin (NES), C-C motif chemokine ligand 2 (CCL2), TNF receptor superfamily member 17 (TNFSF17), and TNF receptor superfamily member 13B (TNFRSF13B). Further analysis revealed potential biomarkers for severe dengue prediction, including TNF superfamily member 15 (TNFSF15), Plasminogen Activator Inhibitor-2 (SERPINB2), motif chemokine ligand 7 (CCL7), aconitate decarboxylase 1 (ACOD1), Metallothionein 1G (MT1G), and Myosin Light Chain Kinase (MYLK2), which were expressed 3.5 times, 2.9 times, 2.3 times, 2.1 times, 1.7 times, and 1.4 times greater, respectively, than dengue patients exhibiting warning signs. The identification of these host biomarkers through RNA-sequencing holds promising implications and potential to augment existing dengue detection algorithms, contributing significantly to improved diagnostic and prognostic capabilities.

Domperidone inhibits dengue virus infection by targeting the viral envelope protein and nonstructural protein 1

Dengue is a mosquito-borne disease caused by dengue virus (DENV) infection, which remains a major public health concern worldwide owing to the lack of specific treatments or antiviral drugs available. This study investigated the potential repurposing of domperidone, an antiemetic and gastrokinetic agent, to control DENV infection. Domperidone was identified by pharmacophore-based virtual screening as a small molecule that can bind to both the viral envelope (E) and the nonstructural protein 1 (NS1) of DENV. Molecular dynamics (MD) simulations and surface plasmon resonance (SPR) analysis were subsequently performed to determine specific interactions of domperidone with the DENV E and NS1 proteins and their binding affinity. Treatment of immortalized human hepatocyte-like cells (imHC) with domperidone could inhibit DENV production and NS1 secretion in a dose-dependent manner following infection with DENV serotype 2. These inhibitory effects were mediated by reduction in viral RNA replication and viral E and NS1 protein expression, but not by interference with virus entry into cells or NS1 oligomerization. The suppression of DENV production and NS1 secretion by domperidone was observed across all four DENV serotypes to varying degrees between different virus strains. The findings from our study suggest viral target-based repurposing of domperidone for modulating DENV.

Utility of VIDAS® Dengue Diagnostic Assays to Differentiate Primary and Secondary Dengue Infection: A Cross-Sectional Study in a Military Hospital from Colombia

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.

Enhancing surveillance for dengue fever in Oyo State, Nigeria - a one health approach

BACKGROUND

Dengue fever (DF) poses a growing global threat, necessitating a comprehensive one-health approach to address its complex interplay between human, animal, and environmental factors. In Oyo State, Nigeria, the true burden of DF remains unknown due to underdiagnosis and misdiagnosis as malaria, exacerbated by poor health-seeking behavior, weak surveillance systems, and inadequate health infrastructure. Adopting a one-health approach is crucial to understanding the dynamics of DF transmission.

METHODS

A cross-sectional study was conducted from January 2022 to April 2023 in 10 high-risk LGAs of Oyo State. It involved screening DENV in 289 febrile human blood samples and 1,015 Aedes species mosquitoes. Viral RNA from human and mosquito specimens was extracted and analyzed using RT-qPCR. A one-step lateral flow immunoassay cassette test kit detected DENV-specific IgM and IgG in humans. DENV IgM-positive participants were screened for Lassa Virus (LASV) to rule out coinfection due to an outbreak of Lassa fever. Mosquitoes recovered were morphologically identified and classified using appropriate taxonomical keys. Meteorological data was obtained from the Nigeria Meteorological Agency. Data was abridged as proportions and correlation analysis was performed.

RESULT

The overall seroprevalence of DENV was 128/289 (44.2%) with 19/289 (6.6%) and 109/289 (37.7%) being IgM and IgG positive respectively. DENV was detected all year round with more cases in the rainy season. LASV and DENV coinfection were detected in a participant. DENV RT-qPCR analysis in febrile patients and mosquitoes was negative. There was a high abundance of Aedes aegypti (79.5%) in all the locations surveyed with Aedes albopictus (12.3%) detected in Ido LGA and Ibadan South-East LGA and Aedes simpsoni (9.1%) in Iwajowa LGA. DF shows moderate to strong positive correlations with Aedes mosquito population, humidity, and rainfall (r = 0.419-0.61, p < 0.05), and a negative correlation with temperature (r =-0.465, p < 0.05).

CONCLUSION

The study reveals a significant burden of DENV in Oyo State. The presence of both IgM and IgG antibodies suggests past exposure and possible recent circulation of the virus. The co-detection of LASV and DENV in one participant highlights the likely potential for co-infection. Although DENV was not detected in febrile patients and mosquitoes through RT-qPCR, the high abundance of Aedes species underscores the risk of transmission. These findings emphasize the need for enhanced surveillance systems, strengthened laboratory services, targeted vector control, and increased awareness.

Oral manifestations of dengue virus infection: a scoping review for clinical dental practice

BACKGROUND

Dengue virus (DENV) infection, a mosquito-borne disease, presents a significant public health challenge globally, with diverse clinical manifestations. Although oral dengue manifestations are uncommon, they can serve as crucial diagnostic indicators and impact patient management in dental practice. This scoping review aims to map the evidence on the oral manifestations associated with DENV infection and their clinical implications for dental practice.

METHODS

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines and was registered on PROSPERO (CRD42022337572). A comprehensive search was conducted across six electronic databases (MEDLINE, Web of Science, Scopus, Embase, Cochrane Library, and LILACS/BBO) up to June 2024. Eligible studies included case reports, case-control, cohort, and cross-sectional studies reporting oral manifestations in patients with DENV infection.

RESULTS

A total of 41 studies were included, comprising 17 case reports, 15 retrospective cohort studies, 4 prospective cohort studies, and 5 cross-sectional studies. Gingival bleeding, oral ulceration, bilateral inflammatory increase in the parotid glands, and lingual hematoma were the most frequently reported oral manifestations. Less common manifestations included Ludwig's angina, osteonecrosis of the jaw, and angular cheilitis. These findings suggest a broad spectrum of oral symptoms that could aid in the early identification and management of dengue patients.

CONCLUSIONS

This review highlights the importance of recognizing oral manifestations in dengue patients, which can facilitate early diagnosis and intervention, particularly in dengue-endemic regions. Dental professionals play a crucial role in identifying these symptoms and improving patient outcomes. Further research is needed to explore the pathophysiological mechanisms underlying these manifestations and to develop standardized protocols for clinical assessment and management.

CLINICAL RELEVANCE

This paper highlights the role of dental professionals in early dengue diagnosis, emphasizing oral manifestations like gingival bleeding. It promotes interdisciplinary care, improving patient outcomes and management in dengue-endemic regions.

A Methodological Approach to Measuring the Impact of TAK-003 for the Prevention of Dengue in Dourados, Brazil: Optimizing Strategies for Public Health

Background/Objectives: Takeda's tetravalent dengue vaccine TAK-003 has been approved by the Brazilian regulatory agency ANVISA for dengue disease prevention in individuals aged 4 to 60 years. Dourados, in the state of Mato Grosso do Sul, became the world's first city to implement a mass vaccination campaign targeting approximately 120,000 individuals. An ongoing collaborative, observational, population-based study using national surveillance and vaccination data was planned to measure the impact of the vaccine on the reduction in dengue incidence. Methods: In this manuscript, the study's methodology, including its programmatic steps and public health relevance, is described. A collaborative assessment with multidisciplinary researchers in Brazil was conducted to identify key programmatic areas for the successful implementation of the study. These areas included feasibility and site selection assessment, methodology selection, vaccination program implementation, and public health importance. Results/Conclusions: Identification of the public health problem and understanding the disease burden, local healthcare infrastructure, and strategic partnerships were critical for a robust feasibility assessment. One of the feasibility criteria identified was the ability of the Dourados Municipal Health Secretary and the principal investigator to conduct an active vaccination campaign, utilizing extramural activities and diverse communication channels to increase vaccine acceptance and coverage. The selection of analytical methods, such as time series analysis, was dependent on the national and local structures of the databases and data availability.

Epidemiological Dynamics and Trends of Dengue Outbreaks in Sao Tome and Principe: A Comprehensive Retrospective Analysis (2022-2024)

BACKGROUND

Dengue has emerged as a significant public health concern in Sao Tome and Principe, with the first documented outbreak occurring between 2022 and 2024. This study examined the epidemiological patterns, environmental determinants, and demographic characteristics of dengue transmission during this period.

METHODS

We conducted a comprehensive retrospective analysis of laboratory-confirmed dengue cases using national surveillance data, clinical records, and environmental monitoring data. Statistical analyses included demographic profiling, temporal trend assessment, and environmental correlation studies using multiple regression modeling.

RESULTS

Among 1264 laboratory-confirmed cases, we observed distinct age-specific vulnerability patterns, with the highest incidence rate in the 70-79 age group (829.6 per 100,000) despite most cases occurring in younger adults. Rainfall emerged as the strongest predictor of dengue transmission (r = 0.96, p < 0.001), explaining 92% of case variance in the regression model. Case distribution showed marked temporal variation, with 91.9% of cases reported in 2022, coinciding with exceptional rainfall (3205 mm). The overall case fatality rate was 0.71% (95% CI: 0.33-1.35), with significant quarterly variations. Geographical analysis revealed concentration in the Água Grande district (68.2% of cases).

CONCLUSIONS

This first comprehensive analysis of dengue in Sao Tome and Principe demonstrates the crucial role of rainfall in disease transmission and reveals important age-specific vulnerability patterns. These findings provide an evidence base for developing targeted interventions, particularly during high-rainfall periods, and suggest the need for age-stratified clinical protocols in similar island settings.

DNA-Based Nanobiosensor for the Colorimetric Detection of Dengue Virus Serotype 2 Synthetic Target Oligonucleotide

Annually, the Philippines is burdened by a high number of infections and deaths due to Dengue. This disease is caused by the Dengue virus (DENV) and is transmitted from one human host to another by the female Aedes aegypti mosquito. Being a developing country, most of the high-risk areas in the Philippines are resource-limited and cannot afford equipment for detection and monitoring. Moreover, traditional clinical diagnoses of DENV infection are costly and time-consuming and require expertise. Hence, it is important to establish effective vector control and surveillance measures. In this study, we developed a DNA-based nanobiosensor for the colorimetric detection of Dengue virus serotype 2 (DENV-2) synthetic target DNA (stDNA S2) using gold nanoparticles (AuNPs). We successfully functionalized dextrin-capped gold nanoparticles with the designed DENV-2 oligonucleotide probes. The detection of the complementary stDNA S2, indicated by the pink-colored solution, was successfully performed within 15 min using 0.40 M NaCl solution. We were able to detect up to 36.14 ng/μL of stDNA S2 with some cross-reactivity observed with one non-complementary target. We believe that our study offers a basis for developing nanobiosensors for other DENV serotypes.

Emergence of a Novel Dengue Virus Serotype-2 Genotype IV Lineage III Strain and Displacement of Dengue Virus Serotype-1 in Central India (2019-2023)

Dengue fever remains a significant public health concern in tropical regions, including Central India, where outbreaks are frequent and associated with high morbidity and mortality. This study investigated the dynamics of dengue virus transmission and evolution in Central India from 2019 to 2023, focusing on the emergence of new strains and their impact on outbreak patterns. For this, 40 mosquito pools and 300 patient samples were recruited for the study. Phylogenetic and Bayesian evolutionary analyses performed on CPrM region and whole genome sequences generated by Sanger and Illumina sequencing, respectively, revealed the emergence and predominance of a novel DENV-2 genotype IV lineage III strain in the 2019 and 2023 outbreaks, which displaced the previously circulating DENV-1 genotype responsible for the 2016-2017 outbreak. Despite pre-existing DENV-1 neutralizing antibodies in the community (67 healthy volunteers), the novel DENV-2 strain exhibited higher viral loads and a greater reproduction number (R0), contributing to rapid disease spread. Molecular clock and Shannon entropy analyses suggest that DENV evolution occurred within the mosquito vector, driven by natural selection. Our findings highlight the importance of continuous DENV surveillance, including genetic characterization in both vectors and hosts, to understand viral evolution and predict future outbreaks. Rapid urbanization and inadequate sanitation in densely populated regions like India create ideal breeding grounds for mosquitoes, facilitating the introduction and establishment of novel DENV strains. Interrupting the vector-DENV-host cycle through targeted interventions is crucial for effective dengue control.

Dengue dynamics, predictions, and future increase under changing monsoon climate in India

The global burden of dengue disease is escalating under the influence of climate change, with India contributing a third of the total. The non-linearity and regional heterogeneity inherent in the climate-dengue relationship and the lack of consistent data makes it difficult to make useful predictions for effective disease prevention. The current study investigates these non-linear climate-dengue links in Pune, a dengue hotspot region in India with a monsoonal climate and presents a model framework for predicting both the near-term and future dengue mortalities. Dengue mortality and meteorological conditions over a twelve-year period (2004-2015) are analyzed using statistical tools and machine learning methods. Our findings point to a significant influence of temperature, rainfall, and relative humidity on dengue mortality in Pune, at a time-lag of 2-5 months, providing sufficient lead time for an early warning targeted at curbing dengue outbreaks. We find that moderate rains spread over the summer monsoon season lead to an increase in dengue mortality, whereas heavy rains reduce it through the flushing effect, indicating the links between dengue and monsoon intraseasonal variability. Additionally, warm temperatures above 27°C and humidity levels between 60% and 78% elevate the risk of dengue. Based on these weather-dengue associations, we developed a machine-learning model utilizing the random forest regression algorithm. The dengue model yields a skillful forecast, achieving a statistically significant correlation coefficient of r = 0.77 and a relatively low Normalized Root Mean Squared Error score of 0.52 between actual and predicted dengue mortalities, at a lead time of two months. The model finds that the relative contributions of temperature, rainfall, and relative humidity to dengue mortality in Pune are 41%, 39%, and 20%, respectively. We use the dengue model in conjunction with the climate change simulations from the Coupled Model Intercomparison Project phase 6 for the future dengue mortality projections under a global warming scenario. In a changing climate, dengue-related mortality in Pune is projected to rise by 13% in the near future (2021-2040), 23-40% in the mid-century (2041-2060), and 30-112% in the late century (2081-2100) under low-to-high emission pathways in response to the associated increase in temperature and changes in monsoon rainfall patterns.