Dengue: A Minireview

Powassan and other emerging neuroinvasive arboviruses in North America

PURPOSE OF REVIEW

Arthropod-borne viruses (arboviruses) represent a group of pathogens with increasing global relevance, some of which cause neuroinvasive disease. Transmitted by arthropod vectors and maintained by a variety of primary and amplifying hosts, epidemics are dependent on numerous environmental and anthropogenic factors. This review serves to highlight several important neuroinvasive arboviruses relevant to North America and discuss the neurologic presentations, diagnosis, outcomes, and future trends.

RECENT FINDINGS

Recent shifts in the epidemiology and ecology of arboviruses in North America include the divergence of arboviruses such as dengue and chikungunya from dependence on enzootic cycles, the geographical expansion of Oropouche virus, and the increasing incidence of some established North American arboviruses such as Powassan virus. Accurate identification of the factors contributing to arboviral outbreaks is critical to improve preventive public health measures. Similarly, further elucidating the relevant pathogen and host factors that determine neuroinvasiveness, neurotropism, and neurovirulence will be key to the development of successful vaccines and targeted therapeutics.

SUMMARY

Arboviruses are an important pathogen relevant to human disease. Familiarity with the presentations, diagnostic workup, treatment and preventive strategies, and expected course is critical for clinicians caring for these patients.

Severe Infections in Returning Travelers

In an increasingly globalized world, it is of paramount importance to be aware of infections that can be contracted during travel-related activities as 43% to 79% of travelers specifically to low-middle income countries return with severe illness. Using a standardized approach to the evaluation of a returning traveler is of utmost importance in developing an appropriately broad differential diagnosis. This includes a thorough travel history paired with an accurate timeline of symptoms all in context of geographically specific risks of infection. Malaria, dengue, and enteric fever are among the most commonly diagnosed travel-related infections.

Characterization of Larvicidal Diterpene Resin Acids in Melipona quadrifasciata Geopropolis via LC-ESI-MS/MS, GC-MS and Computational Analysis

RATIONALE

Dengue, an arboviral disease transmitted by the Aedes aegypti mosquito, is a major global public health problem challenge. Insecticides based on natural products can provide a good alternative to synthetic agents, as they are safer for both the environment and human health. This study evaluated the activity of geopropolis from stingless bees and Apis mellifera bees on Ae. aegypti, using mass spectrometry approaches to identify compounds with larvicidal potential against Ae. aegypti.

METHODS

The larvicidal activity of propolis from stingless bees and A. mellifera, as well as the Melipona quadrisfasciata geopropolis (a mixture of soil/clay and propolis), was evaluated against Ae. aegypti larvae (Rockefeller strain). ESI-MS/MS analyses were performed using a quadrupole/time-of-flight mass spectrometer for all geopropolis samples, the geopropolis from Melipona quadrifasciata was also analyzed using an ion trap instrument. The ESI-qTOF-MS/MS data were processed in a spectral similarity network using GNPS. Molecular annotation of potential compounds was performed using the in silico tool called NAP. Gas-phase fragmentation mechanisms were proposed in conjunction with computational chemistry studies. Silylated geopropolis samples were also analyzed by GC-MS.

RESULTS

Geopropolis from the stingless bee M. quadrifasciata caused 90% and 100% mortality in Ae. aegypti larvae after 24 and 48 h of exposure, respectively, exhibiting the highest activity. Mass spectrometry-based molecular network approach supported the suggestion of discriminant compounds between active and inactive samples. The combination of NAP predictions with gas-phase reactions from ESI-MS/MS and EI-MS data facilitated the annotation of larvicidal compounds, including diterpene resin acids, such as dehydroabietic acid and its derivatives, abietic acid, and pimaranes.

CONCLUSION

The combination of HPLC-MS/MS and GC-MS data suggests that diterpene resin acids contribute to the larvicidal effect of M. quadrifasciata geopropolis on Ae. aegypti, enhancing our understanding of potentially bioactive natural products against the arbovirus vector.

Arboviruses in UK Armed Forces: a review of historical cases and identification of future threats

INTRODUCTION

Arboviruses are a diverse group of arthropod-borne pathogens and are emerging global public health threats with no approved therapeutics. Arboviruses are spreading rapidly, posing a health threat to UK Armed Forces (UKAF) service personnel (SP) through deployment to endemic regions. There are limited data on the burden of arboviral infections in UKAF SP.

METHODS

A retrospective service evaluation of UKAF electronic healthcare records (eHRs) and statutory notifications to the Defence Public Health Unit was conducted. Cases with possible/confirmed dengue, chikungunya or Zika virus infections between 2005 and 2023 were included. eHRs were interrogated and trends analysed.

RESULTS

Of 107 suspected infections between 2005 and 2023, 49 (45.8%) were laboratory-confirmed. Dengue fever was the most common (45/49) followed by chikungunya (3/49) and Zika (1/49) virus infections. The average yearly incidence of reported dengue infection increased from 0.51 cases per 100 000 UKAF SP per year in 2009-2011 to 3.85 cases per 100 000 SP per year in 2021-2023. 19/45 (42.2%) cases occurred during operational deployments and 24/45 (53.3%) during non-military activity. Dengue infection was most frequently acquired in Southeast Asia.Using WHO clinical severity criteria, 33/45 (73.3%) had dengue with warning signs and 5 (11.1%) had severe dengue. 23/45 (51.1%) dengue cases were hospitalised (median length of stay 5 days, IQR 3, range 1-9). No dengue fatalities or medical discharges occurred. Occupational impact was significant, with a median of 11 days stood down (IQR 10, range 0-45); 3/19 (15.8%) cases on operations required aeromedical evacuation (AEROMED). One deployed case of chikungunya required AEROMED and a 35-day downgrade.

CONCLUSIONS

Reports of arboviral infections, particularly dengue, are increasing in UKAF personnel, presenting an emerging health threat. This has implications for UKAF provision of deployed diagnostics and dengue vaccination policy. The rapid spread of arboviruses outside their traditional geographical areas, including into Europe, necessitates further surveillance and requires diagnostic and therapeutic research.

Changes and application prospects of biomolecular materials in small extracellular vesicles (sEVs) after flavivirus infection

Small extracellular vesicles (sEVs), also known as exosomes, are membranous vesicles filled with various proteins and nucleic acids, serving as a communication vector between cells. Recent research has highlighted their role in viral diseases. This review synthesizes current understanding of viral sEVs and includes recent findings on sEVs infected with flaviviruses. It discusses the implications of viral sEVs research for advancing arbovirus sEVs research and anticipates the potential applications of sEVs in flavivirus infections.

Ultrasensitive Peptide-Based Electrochemical Biosensor for Universal Diagnostic of Dengue

Dengue is a neglected disease mainly affecting tropical and subtropical countries. The diagnosis of dengue fever is still a problem since most of it is made from whole or recombinant DENV proteins, which present cross-reactions with other members of the Flavivirus family. Therefore, there is still a huge demand for new diagnostic methods that provide rapid, low-cost, easy-to-use confirmation. Thus, in this study, we developed an affordable electrochemical biosensor for rapidly detecting immunoglobulin G (IgG) serological antibodies in the sera of DENV-infected patients. An identified linear B-cell epitope (DENV/18) specific for DENV 1-4 serotypes recognized by IgG in patient sera was selected as a target molecule after a microarray of peptides using the SPOT-synthesis methodology. After chemical synthesis, the DENV/18-peptide was immobilized on the surface of the working electrode of a commercially available screen-printed gold electrode (SPGE). The capture of DENV-specific IgG allowed for the formation of an immunocomplex that was measured by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using a potassium ferrocyanide/ferricyanide ([Fe(CN)6]3-/4-) electrochemical probe. An evaluation of the biosensor's performance showed a detection limit of 100 µg mL-1 for the synthetic peptides (DENV/18) and 1.21 ng mL-1 in CV and 0.43 ng mL-1 in DPV for human serum, with a sensitivity of 7.21 µA in CV and 8.79 µA in DPV. The differentiation of infected and uninfected individuals was possible even at a high dilution factor that reduced the required sample volumes to a few microliters. The final device proved suitable for diagnosing DENV by analyzing real serum samples, and the results showed good agreement with molecular biology diagnostics. The flexibility to conjugate other antigenic peptides to SPEs suggests that this technology could be rapidly adapted to diagnose other pathogens.

Modeling and Molecular Dynamics Studies of Flavone-DENV E-3 Protein-SWCNT Interaction at the Flavonoid Binding Sites

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

Meningoencephalitis probably associated with dengue infection in an 84-year-old patient: A case report

Dengue meningoencephalitis is a rare neurological complication of dengue infection, characterized by inflammation of the brain and leptomeninges. We present the case of an 81-year-old female patient with a five-day history of fever, accompanied by altered consciousness, seizures, and meningeal signs. Dengue infection was confirmed by a positive RT-PCR result in blood, and cerebrospinal fluid analysis revealed lymphocytic pleocytosis, suggestive of a viral infectious process. Additionally, an electroencephalogram showed focal epileptiform activity. This is the first reported case of dengue meningoencephalitis in Central America. This case highlights the importance of considering dengue virus as a potential etiological agent in patients presenting with fever and acute alterations in consciousness secondary to a viral infectious process. The publication of this case is relevant to enhance early recognition of rare neurological complications such as dengue meningoencephalitis, promoting timely intervention that may positively influence patient prognosis.

Dengue dynamics in Bali: Serotype shifts, genotype replacement and multiple virus lineage circulation in the last 10 years

BACKGROUND

Bali, one of the world's most popular tourist destinations, is hyper-endemic to dengue, an acute febrile illness caused by infection with dengue virus (DENV). Outbreaks of dengue occur annually with worrisome rates of morbidity and mortality. Despite this, comprehensive and continuous virus surveillance is yet to be established. We conducted DENV serotype and genotype surveillance in Bali to monitor viral transmission dynamics.

METHODS

We enrolled febrile patients with dengue clinical symptoms in hospitals in Denpasar, Bali. Clinical evaluations and laboratory assessments were conducted, and blood samples were collected. DENV serotypes were determined using RT-PCR, and genotyping was performed by sequencing the envelope protein gene and the complete genomes. Subsequently, phylogenetic analyses were conducted to analyse the recent data alongside retrospective sequence data.

RESULTS

A total of 62 and 66 dengue patients were recruited during 2018-2020 and 2022, and from these, we obtained DENV serotype data for 49 and 48 individuals, respectively. Among the DENV analysed, the most prevalent serotype in 2018-2020 was DENV-1 (30%) and shifted to DENV-3 (57.6%) in 2022. When compared to data from the last 10 years, serotype shifting was clearly observed. We sequenced the genomes of 60 isolates and observed the presence of multiple virus lineages and the replacement of Genotype IV of DENV-1 with Genotype I. The Cosmopolitan, Genotype I and Genotype II remained the predominant genotypes for DENV-2, DENV-3 and DENV-4, respectively.

CONCLUSION

We reveal that DENV serotype predominance in Bali has been shifting in the past 10 years. While genotype replacement occurred, continuous circulation of local endemic viruses was responsible for the annual outbreak of dengue. These findings indicate the genetic diversity and dynamic nature of DENV circulating in Bali. Routine virus surveillance is important to understand the cyclical patterns of DENV serotypes that is useful to predict the future outbreaks.

Synergistic modeling of hemorrhagic dengue fever: Passive immunity dynamics and time-delay neural network analysis

Dengue fever poses a formidable epidemiological challenge, particularly for vulnerable groups such as infants. This research paper establishes a mathematical model to describe the dynamics of secondary immunity in infants against dengue hemorrhagic fever, who acquired primary immunity through maternal antibodies. The effect of passive immunity in the form of dengue immunoglobulin is analyzed for high-risk patients for different scenarios, including standard dengue infections, host with pre-existing immunity, delayed diagnosis or treatment, and end-stage dengue cases. Convergence analysis of the model is performed through disease free and disease endemic equilibrium points in terms of basic reproduction number R0 along with local stability of disease-free equilibrium point. Adams numerical approach is utilized to simulate dengue disease/immunity interactions. A time delay exogenous neural network approach coupled with Levenberg-Marquardt optimization is designed to characterize, model and simulate these curated scenarios. Exhaustive neural network procedures determine the efficacy of the neural network approach by means of mean square error (MSE) loss charts, error correlation graphs, error histogram analysis and time-series prediction charts. The impeccable characterization of the dengue fever scenarios is supported by extremely low MSE results of the order 10-9 to 10-11. To further showcase the competency of the neural network predictions, an exhaustive comparative study against the reference numerical solutions is illustrated with absolute errors in the range of 10-3 to 10-5. The novel development of mathematical model coupled with time-delay exogenous neural networks significantly enhances our ability to understand and predict the intricate dengue hemorrhagic fever dynamics allowing for targeted interventions for such infectious disease and epidemiological scenarios.

Pathogenesis and clinical management of arboviral diseases

Arboviral diseases are viral infections transmitted to humans through the bites of arthropods, such as mosquitoes, often causing a variety of pathologies associated with high levels of morbidity and mortality. Over the past decades, these infections have proven to be a significant challenge to health systems worldwide, particularly following the considerable geographic expansion of the dengue virus (DENV) and its most recent outbreak in Latin America as well as the difficult-to-control outbreaks of yellow fever virus (YFV), chikungunya virus (CHIKV), and Zika virus (ZIKV), leaving behind a substantial portion of the population with complications related to these infections. Currently, the world is experiencing a period of intense globalization, which, combined with global warming, directly contributes to wider dissemination of arbovirus vectors across the globe. Consequently, all continents remain on high alert for potential new outbreaks. Thus, this review aims to provide a comprehensive understanding of the pathogenesis of the four main arboviruses today (DENV, ZIKV, YFV, and CHIKV) discussing their viral characteristics, immune responses, and mechanisms of viral evasion, as well as important clinical aspects for patient management. This includes associated symptoms, laboratory tests, treatments, existing or developing vaccines and the main associated complications, thus integrating a broad historical, scientific and clinical approach.

A one-pot method for universal Dengue virus detection by combining RT-RPA amplification and CRISPR/Cas12a assay

Dengue Virus (DENV) is a life-threatening pathogen leading to dengue fever, which brings about huge public health challenges globally. However, traditional detection methods currently fail to meet the increasing demands of clinic practice in terms of speed, simplicity, and accuracy. To address these limitations, we developed a novel, rapid, and highly sensitive diagnostic method for universal DENV detection by integrating recombinase polymerase amplification (RPA) assay and the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) and associated (Cas) protein 12a (CRISPR/Cas12a) system into one-pot. This approach achieves exceptional sensitivity and specificity for DENV detection, with the entire process completed within 40 min, without the need for sophisticated equipment. The limit of detection (LOD) was determined to be 91.7 copies/test. Using this one-pot RT-RPA CRISPR/Cas12a detection system, all four serotypes of DENV (1 to 4) were successfully identified. In terms of specificity, the assay accurately detected DENV-infected positive samples without cross-reactivity with four other interfering viruses-infected samples (VSV, SeV, HSV-1 and IAV). Furthermore, we established a universal DENV RT-RPA-CRISPR/Cas12a-lateral flow dipstick (LFD) platform, which successfully identified all four serotypes of DENV with a sensitivity of approximately 250 copies/test. Collectively, our method not only provides a robust alternative for universal DENV detection but also offers valuable insights for the identification of other viruses.

Global hotspots and academic trends of vector-borne diseases in the order Diptera (Arthropoda: Insecta): a bibliometric visualisation

Blood-sucking arthropods belonging to the order Diptera, encompassing mosquitoes, sandflies, midges, blackflies, horseflies and tsetseflies serve as vectors for a myriad of pathogens, inflicting substantial harm on both human and animal health globally. The analysis and visualisation of global hotspots and trends pertaining to vector-borne diseases, stemming from these six categories of arthropods, constituted a reliable reference for further delving into the research on Diptera insect vectors. To achieve this, we mined literature information from the Web of Science Core Collection (WoSCC), encompassing all publications related to these six arthropod groups, and leveraged VOSviewer software for bibliometric analysis and visualisation. This resulted in the construction of comprehensive relationship networks encompassing keywords, countries, institutions and authors. A comprehensive analysis encompassed 41,393 research publications, segmented into 34,363 studies on mosquitoes, 1,668 on sandflies, 3,665 on midges, 241 on blackflies, 336 on horseflies and 1,120 on tsetseflies. The bibliometric analysis, coupled with visual characterisation, offered a multifaceted synthesis of the gathered data from diverse angles. The scientometric analysis quantitatively assessed and identified the contributions of keywords, countries, institutions and authors pertaining to the research of each vector. The resulting visualisation knowledge maps elucidate collaborative network relationships within the respective vector research domains. This research endeavour stems from numerous driving forces, and a comprehensive grasp of its future trajectories and research hotspots can empower scientists with historical perspectives and forward-looking insights, fostering the formulation of innovative and impactful research ideas for the years ahead.

Comparative analysis of bacterial microbiota in Aedes aegypti (Diptera: Culicidae): insights from field and laboratory populations in Colombia

Comparative studies of the microbiota in whole-body mosquitoes from natural populations and laboratory-reared specimens are scarce, particularly in tropical countries like Colombia, where understanding microbial patterns is critical for effective disease control and vector management. This study examines the bacterial microbiota of Aedes aegypti by comparing field-collected mosquitoes from 3 Colombian regions (Southern Amazon, Central Andean region, and Northern Caribbean coast) with laboratory strains (Rockefeller, Otanche, and Tolima). These regions are highly endemic for dengue and are associated with lineage 1 of Ae. aegypti, known for its elevated vector competence. Using next-generation sequencing of the 16S rRNA gene with Illumina technology, we found that field-collected mosquitoes exhibited significantly higher alpha and beta diversity compared to laboratory-reared specimens. Field mosquitoes were enriched with bacterial families such as Acetobacteraceae, Lactobacillaceae, and Bacillaceae, while laboratory mosquitoes showed a greater abundance of Enterobacteriaceae. Differential abundance analysis revealed that Acetobacter and Bacillus predominated in field mosquitoes, whereas Asaia, Cedacea, and Chryseobacterium were more common in laboratory specimens. Notably, Pseudomonas and Acinetobacter were consistently abundant across all samples. Our findings suggest that environmental factors, such as habitat and diet, significantly influence the bacterial composition and diversity of Ae. aegypti in Colombia. Future research should further explore how these factors, alongside genetic components, shape mosquito-microbiota interactions and their implications for disease transmission and vector competence.

Insecticide Resistance Status of Aedes aegypti Adults and Larvae in Nouakchott, Mauritania

Aedes aegypti mosquitoes are established throughout Nouakchott, Mauritania, where its insecticide resistance status is unknown and dengue has become endemo-epidemic since 2014. Eggs were collected using ovitraps at 12 sites in five districts of Nouakchott, in August 2024. Adult females and larvae of the F1 generation were used for bioassays. Permethrin, deltamethrin, bendiocarb, and malathion were evaluated at discriminating concentrations. Larval assays were carried out at seven concentrations with Bacillus thuriengensis var israelensis (Bti) and temephos. The presence of knockdown resistance (kdr) mutations known to be associated with pyrethroid resistance was assessed by polymerase chain reaction and amplicons sequencing. Adults showed high levels of resistance to all insecticides tested. Larvae were susceptible to Bti (LD50 < 50 µg/L) and temephos (LD50% = 6.8 ± 0.7 µg/L). Only three kdr point mutations, S989P, V1016G, and F1534C, were found. The tri-locus genotypes SP/VG/FC were significantly associated with pyrethroid survival while only the tri-locus genotypes PP/GG/FF showed significant association with deltamethrin resistance. Given their level of insecticide resistance, there is an urgent need to control Ae. aegypti populations by several methods, including the use of biological larvicides, physical elimination of peridomestic breeding sites, water drainage, and public education to prevent arbovirus transmission.

Whole genome sequencing and phylogenetic analysis of dengue virus in Central Nepal from 2022 to 2023

BACKGROUND

In Nepal, dengue is an emerging disease of growing concern as outbreaks are increasing in both size and geographic reach and beginning to affect areas previously thought dengue-free. Dengue genomic surveillance has previously been limited within Nepal; however, with the increase in accessibility to sequencing technologies since the COVID-19 pandemic, it has recently become more feasible.

METHODS

This hospital-based retrospective study utilized banked samples from the 2022 and 2023 dengue seasons from Dhulikhel Hospital/Kathmandu University Hospital in Central Nepal. Next-generation sequencing was performed to obtain whole genome sequences of dengue virus which were analyzed phylogenetically using a maximum likelihood GTR + G model. Mutations were evaluated across viral particle region using the GISAID DengueServer.

RESULTS

We obtained 41 full-length sequences of DENV from 80 PCR-positive samples, including 24 sequences (58.5%) from 2022 and 17 sequences (41.5%) from 2023. We identified a shift in the majority serotype of our samples from DENV1 in 2022 to DENV3 in 2023, though 3 out of the 4 serotypes were identified in both years. Phylogenetic analysis revealed clusters within genotype III of DENV1 and genotype III of DENV3 closely related to strains from an outbreak of DENV in northern India in 2018-2019. DENV2 sequences fell into the cosmopolitan genotype IV-A1 and IV-B2 clades and were related to sequences from South and Southeast Asia and the USA, pointing to the global nature of dengue transmission. NS3 showed the highest frequency of mutation, whereas NS2B, NS4, NS5, and E were the most conserved. The most common mutations found were substitutions L17M and T20I in the 2 K peptide. A high number of mutations were observed in DENV3, followed by DENV2, with some mutations being unique to specific serotypes and others matching previously reported strains.

CONCLUSIONS

We identified possible clade shifts in the DENV1 and 2 populations and a rising prevalence of DENV3. Our study showed a high level of serotype diversity of DENV circulating in Central Nepal. Furthermore, our results indicate that DENV populations in Nepal are related to a geographically diverse set of sequences but are most strongly influenced by Indian strains of DENV.

Dengue virus is particularly sensitive to interference with long-chain fatty acid elongation and desaturation

Orthoflaviviruses are emerging arthropod-borne pathogens whose replication cycle is tightly linked to host lipid metabolism. Previous lipidomic studies demonstrated that infection with the closely related hepatitis C virus (HCV) changes the fatty acid (FA) profile of several lipid classes. Lipids in HCV-infected cells had more very long-chain and desaturated FAs and viral replication relied on functional FA elongation and desaturation. Here, we systematically analyzed the role of FA elongases and desaturases in infection models of the most prevalent pathogenic orthoflaviviruses, dengue (DENV), Zika (ZIKV), West Nile (WNV), yellow fever (YFV), and tick-borne encephalitis virus (TBEV). Knockdown of desaturases and elongases in Huh7 cells only marginally affected ZIKV, WNV, YFV, and TBEV replication, while DENV titers were strongly reduced. This was most prominent for enzymes involved in very long-chain fatty acid synthesis. In detail, knockdown of the FA elongase ELOVL4, which catalyzes ultra-long-chain FA synthesis, significantly reduced DENV titers, decreased the formation of replication intermediates, and lowered viral protein levels in DENV-infected hepatoma cells, suggesting a function of ELOVL4 in DENV RNA replication. In contrast, the activity of FA desaturase FADS2, rate-limiting in poly-unsaturated FA biosynthesis, is not involved in viral RNA replication or translation, but is essentially required for the formation of infectious DENV particles. Further, in immunocompetent immortalized microglial cells, FADS2 deletion additionally limits viral replication through increased expression of interferon-stimulated genes in response to DENV infection. Taken together, enzymes involved in very long-chain FA synthesis are critical for different steps of DENV replication.

[Dengue treatments and vaccines]

Dengue fever is a viral disease transmitted by mosquitoes of the Aedes genus, whose incidence and range have been steadily increasing in recent decades. Causing hemorrhagic fever in severe cases, it affects the inter-tropical regions of the world and threatens to spread to new geographical areas. Its complex pathophysiology and the existence of four genetically distant serotypes make vaccine development a challenge. Currently, there is no specific treatment against dengue fever and only a few vaccines are marketed or in development, with some limitations on their use. It is therefore necessary to develop new vaccines and identify new molecules with antiviral properties to reduce the economic and public health burden of this disease in endemic areas.

Advances in the Epidemiology, Pathogenesis, Diagnostic Methods, and Vaccine Development of Dengue Fever: A Comprehensive Review

Dengue fever (DF) is a common mosquito-borne viral infection caused by any of the four dengue virus (DENV) serotypes. In recent years, the global incidence of DF has risen rapidly, which has widely threatened the health of millions of people in the United States, Southeast Asia, and the Western Pacific. The challenges for the prevention and control of DENV infection have become increasingly severe. Over the years, advances in the area of DF research have been continuously updating. In this review, we provide an updated and more in-depth overview of dengue epidemiology and pathogenesis, along with recent progress in diagnostic approaches (including methods to address cross-reactivity with other flaviviruses) and an expanded discussion of current dengue vaccine development, such as CYD-TDV (Dengvaxia), TV003/TV005, and the new TAK-003. This comprehensive perspective aims to offer references for the prevention, clinical diagnosis, and control of the disease.

Maternal and foetal outcomes in women with gestational Dengue: A systematic review

Introduction

Dengue is a mosquito-borne viral disease. It has been associated with high maternal and foetal morbidity and mortality. Therefore, this study aimed to describe the outcomes of Dengue infection in pregnant women in terms of maternal bleeding, miscarriage, preterm delivery, severe Dengue, Dengue shock and maternal mortality, as well as foetal outcomes in terms of foetal distress, low birth weight and neonatal mortality.

Methods

This systematic review followed PRISMA guidelines and was PROSPERO-registered (CRD42024578212). It examined publications from 2019-2024 across major databases, including Medline, Scopus, Web of Science, Scielo, and CENTRAL. The selection process utilised Rayyan AI® for duplicate removal, followed by a two-reviewer screening system. The two reviewers initially filtered the papers by title and, then, by abstract; finally, they read the full text and chose the articles to synthesise. The same two reviewers performed data extraction independently using a Microsoft Excel® matrix. For the risk of bias assessment and Quality evaluation, the ROBINS-E tool and the STROBE guidelines were employed.

Results

Maternal Dengue was associated with an increased risk of preterm delivery and complications such as obstetric bleeding, especially postpartum haemorrhage, which was a complication that reached proportions of up to 25% in some studies. Severe Dengue and Dengue shock were also complications present in these women; thrombocytopenia was the most common sign, and complications such as pre-eclampsia and multi-organ dysfunction appeared, leading to fatal outcomes such as maternal and foetal mortality.

Conclusions

Dengue infection during gestation carries significant maternal health risks, including complications such as bleeding, miscarriage and preterm delivery. In addition, it is associated with foetal distress and low birth weight, as well as increased foetal and neonatal mortality, highlighting the need for vigilance and appropriate medical care.

A review of the mosquito-borne flaviviruses: Dengue virus and West Nile virus in Southern Africa

Dengue virus (DENV) and West Nile (WNV) viruses are important re-emerging mosquito-borne members of the genus Flavivirus that are under-recognized in many parts of Africa. This review aims to evaluate the existing literature on the transmission, epidemiology, diagnostic techniques, clinical presentation and prevention of infection with DENV and WNV in Southern Africa. Literature shows that both DENV and WNV are transmitted by mosquitoes of Aedes spp. and Culex species., respectively, and both viruses are widespread in the Southern African region. Epidemiologically, sporadic outbreaks have been reported of both DENV and WNV in various Southern African countries, indicating the ongoing threat of these viruses. However, the lack of comprehensive surveillance and diagnostic capacity challenges accurate estimation of their true prevalence. Diagnostic techniques for DENV and WNV involve serological tests, molecular tests and viral isolation, enabling prompt diagnosis and differentiation from other febrile illnesses. In Southern Africa, infection with DENV and WNV presents significant public health concerns, with the clinical presentation of both infections ranging from asymptomatic cases to severe manifestations. Symptoms of infection include high fever, myalgia, rash, and, in severe cases, haemorrhagic fever for DENV and neurological complications for WNV. No specific antiviral treatment exists for either virus, underscoring the importance of supportive care and symptom management. To prevent the spread of DENV and WNV in Southern African countries, a combination of prevention and treatment strategies should be employed, including effective mosquito control, continuous monitoring of vector population dynamics, public health education, and surveillance and reporting systems for averting future outbreaks.

Development of a multi-epitope vaccine candidate to combat SARS-CoV-2 and dengue virus co-infection through an immunoinformatic approach

Background

Although the SARS-CoV-2 and dengue viruses seriously endanger human health, there is presently no vaccine that can stop a person from contracting both viruses at the same time. In this study, four antigens from SARS-CoV-2 and dengue virus were tested for immunogenicity, antigenicity, allergenicity, and toxicity and chosen to predict dominant T- and B-cell epitopes.

Methods

For designing a multi-epitope vaccine, the sequences were retrieved, and using bioinformatics and immunoinformatics, the physicochemical and immunological properties, as well as secondary structures, of the vaccine were predicted and studied. Additionally, the three-dimensional structure was estimated, improved upon, and confirmed using bioinformatics methods before being docked with TLR-2 and TLR-4. Eight helper T-cell lymphocyte (HTL) epitopes, ten cytotoxic T-cell lymphocyte (CTL) epitopes, nine B-cell epitopes, and TLR agonists were used to create a new multi-epitope vaccine. Furthermore, according to the immunological stimulation hypothesis, the vaccine could stimulate T and B cells to create large quantities of Th1 cytokines and antibodies.

Results

The study indicates that the developed vaccine is a favorable vaccine candidate with antigenicity, immunogenicity, non-toxicity, and non-allergenicity properties. The vaccine construct was made up of 460 amino acids, had an MW of 49391.51 Da, a theoretical pI of 9.86, and the formula C2203H3433N643O618S18, a lipid index of 39.84, a GRAVY of -0.473, an aliphatic index of 63.80, and an instability index of 39.84, which classifies the protein to be stable.

Conclusion

The acquired data showed that both vaccine designs had a considerable chance of preventing the co-infection of SARS-CoV-2 and dengue virus and that they demonstrate good results following in-silico testing. Furthermore, the vaccine may be an effective strategy in preventing SARS-CoV-2 and dengue since it can cause noticeably high levels of Th1 cytokines and antibodies.

Investigation of severe dengue outbreak in Maumere, East Nusa Tenggara, Indonesia: Clinical, serological, and virological features

BACKGROUND

Dengue, an acute febrile disease caused by dengue virus (DENV) infection, is endemic to Indonesia. During early 2020, an outbreak of severe dengue occurred in Maumere, East Nusa Tenggara province, a region with low dengue endemicity with limited data on the characteristics of the circulating DENV. By 18 March 2020, 1396 cases were reported with 14 fatalities. Investigation was conducted to understand the cause and characteristics of the outbreak.

METHODS

Sera were collected from 133 patients with dengue-like symptoms through random sampling at TC Hillers Hospital, Maumere during outbreak between February and June 2020. Dengue was confirmed using NS1 and/or RT-PCR detection. Serological status was determined using IgG/IgM ELISA and plaque reduction neutralization test (PRNT). DENV serotyping and genome sequencing were performed to identify the DENV serotype and genotype.

RESULTS

We recruited suspected dengue patients attending the hospital during the outbreak. Dengue was confirmed in 72.2% (96/133), while 18.8% (25/133) were diagnosed as probable dengue. Children under 18 years old accounted for 85.1% (103/121) of dengue cases. Severe dengue accounted for 94.2% (81/86) of cases. Secondary infections made up 92.6% (112/121) of cases. Serotyping detected 87.3% (62/71) as DENV-3, 7.0% (5/71) as DENV-4, 2.8% (2/71) as DENV-1, and 2.8% (2/71) as DENV-2. Phylogenetic analysis revealed close evolutionary relationship of Maumere DENV to viruses from other Indonesian regions, especially Bali and Kupang. PRNT on DENV-3 secondary infections patients detected the presence of DENV-2 and DENV-4 neutralizing antibodies.

CONCLUSION

The severe dengue outbreak in Maumere is caused by DENV-3 introduced from nearby islands. The high proportion of secondary infections likely contributes to the severity of the disease. The high percentage of anti-dengue neutralizing antibodies for multiple serotypes and the high proportion of anti-dengue IgG in young children suggests a history of dengue transmission with a high infection rate in the area.

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.

Diversity of Gut Bacteria of Field-Collected Aedes aegypti Larvae and Females, Resistant to Temephos and Deltamethrin

The Aedes aegypti mosquito serves as a vector for several diseases, including dengue, Zika, chikungunya, and yellow fever. This species is well adapted to urban environments and poses a significant threat to public health. Some studies suggest that the gut bacteria of insect vectors may play a crucial role in developing resistance to insecticides. This study assessed the resistance of Ae. aegypti from Florencia, Caquetá, to temephos and deltamethrin and analyzed the diversity of gut bacteria in resistant larvae and adult females. Larvae exhibited resistance to temephos at a lethal concentration 50 (LC50) of 0.034 µg/mL, while females showed resistance to deltamethrin at a discriminant concentration of 10 µg/mL. The bacterial load in the guts of deltamethrin-treated females (3.42 × 106 CFU/mL) was significantly higher compared to temephos-treated larvae (9.4 × 105 CFU/mL) and untreated females (8 × 104 CFU/mL). A total of sixty-eight bacterial strains were isolated from the guts of both larval and resistant females Ae. aegypti, with 31 strains identified through 16S rRNA gene analysis and 11 confirmed by gyrB gene sequencing. In untreated females, Bacillus comprised 12.55% of the gut bacteria and was identified as an exclusive genus. In resistant larvae, Serratia was the most abundant and exclusive genus, accounting for 35.29%, while in resistant females, Cedecea was the predominant genus, representing 66.67%. These findings suggest that gut bacteria may influence the resistance of Ae. aegypti to temephos and deltamethrin. Furthermore, this research provides valuable information that can be considered for the design of local vector control strategies. The results highlight new research focused on the study of insecticide tolerance and degradation within the gut microbiota of insect vectors of arboviruses.

Molecular Epidemiology of Dengue Viruses in Lao People's Democratic Republic, 2020-2023

Dengue fever is a widespread mosquito-borne viral disease caused by infections with dengue virus (DENV). Since its initial detection in 1979, the disease has posed a significant public health threat to the Lao People's Democratic Republic (Lao PDR). Surveillance is crucial for understanding the circulation of DENV in endemic regions and identifying potential hot spots with higher-than-expected case numbers of dengue fever. In this study, we present the results from our surveillance activities in the Lao PDR spanning 2020-2023. While quarantine restrictions from the COVID-19 pandemic posed substantial disruptions to performing DENV surveillance, over 8800 samples were tested during this period, with a positive rate of close to 60%. Cases were reported from all three regions (northern, Central, and southern) of the Lao PDR. Three circulating serotypes (DENV-1, DENV-2, and DENV-4) were detected, with DENV-1 dominant in 2021 and 2022, while DENV-2 was dominant in 2020 and 2023. Phylogenetic analyses suggest that the genotypes of DENV-1, DENV-2, and DENV-4 were closely related to corresponding isolates from neighboring countries. These findings provide an update on the nature of DENV cases detected in the Lao PDR and underscore the critical importance of sustaining a robust surveillance network to track infections.

Current Dengue Virus Vaccine Developments and Future Directions

Dengue fever (DF), a leading arboviral disease globally, is caused by the Dengue virus (DENV) and represents a significant public health concern, with an estimated 390 million cases reported annually. Due to the complexity of the various dengue variants and the severity of the disease, vaccination emerges as the essential strategy for combating this widespread infectious disease. The absence of specific antiviral medications underscores the critical need for developing a Dengue vaccine. This review aims to present the current status and future prospects of Dengue vaccine development. Further, this review elaborates on the various strategies employed in vaccine development, including attenuated, inactivated, subunit, and viral vector vaccines. Each approach is evaluated based on its immunogenicity, safety, and efficacy, drawing on data from preclinical and clinical studies to highlight the strengths and limitations of each candidate vaccine. The current study sheds light on future directions and research priorities in developing Dengue vaccines. In conclusion, the development of a Dengue vaccine holds significant potential for reducing the global burden of DF. However, challenges remain in terms of vaccine safety, efficacy, delivery, and availability. Overcoming these challenges, coupled with advancements in vaccine technology, could lead to better control and prevention of Dengue, thereby enhancing public health and quality of life.

Protective effects of herbal compounds against cyclophosphamide-induced organ toxicity: a pathway-centered approach

Cyclophosphamide is a key component of numerous chemotherapeutic protocols, demonstrating broad-spectrum efficacy against various malignancies and non-cancerous conditions. This review examines CPM's metabolic pathways, therapeutic applications, and its resulting organ-specific toxicities. Despite its clinical benefits in treating nephrotic syndrome, encephalomyelitis, breast cancer, ovarian cancer, and other diseases, CPM is associated with significant adverse effects on the kidneys, liver, heart, lungs, and intestines. The discussion delves into the molecular mechanisms underlying these toxicities, highlighting dysregulation in key signaling pathways, including Nrf2, NF-κB, MAPK/ERK, and AKT. In addressing these challenges, recent studies have identified various herbal drugs and phytochemicals capable of mitigating CPM-induced toxicity. Notable compounds such as cinnamaldehyde, baicalin, quercetin, and curcumin have demonstrated protective effects. Integrating these herbal formulations with CPM therapy is proposed to enhance patient safety and treatment efficacy. This review underscores the influence of CPM on apoptosis and inflammation pathways, which lead to alterations in organ-specific biomarkers. Phytochemicals may exert protective effects by restoring disrupted signaling pathways and normalizing altered biomarkers. The compilation of phytochemicals presented in this review serves as a valuable resource for researchers exploring other herbal products with potential protective effects against CPM toxicity. A significant gap in the current literature is the lack of clinical trials evaluating phytochemicals that mitigate CPM toxicity in vivo. Rigorous clinical studies are necessary to establish the efficacy and safety of herbal formulations in cancer treatment. Such research will clarify the role of natural remedies in complementing conventional therapies, ultimately improving patient outcomes.

Estimation and Characterization of Dengue Serotypes in Patients Presenting with Dengue Fever at Makkah Hospitals

Dengue fever is caused by four common serotypes of the dengue virus (DENV-1, DENV-2, DENV-3, and DENV-4). Patients infected with one serotype may develop lifelong serotype-specific protective immunity. However, they remain susceptible to reinfection with the other serotypes, often increasing the risk of severe forms of dengue. This cross-sectional study investigates the prevalence of the four dengue serotypes in patients who presented with dengue fever at Makkah hospitals between April 2023 and May 2024. Data were collected from the medical records of the Regional Laboratory in Makkah, Saudi Arabia. The 238 positive dengue samples included 185 samples (77.73%) from male patients. The average age of the patients was 37.65 years (SD = 15.05). Dengue type 2 was the most common serotype, followed by type 1, type 3, and type 4. Most of the dengue patients were Saudi nationals, followed by Egyptians. There were 11 dengue-positive samples that were not diagnosed with any of the four dengue serotypes. Since Makkah receives numerous international travelers, these samples might contain novel dengue serotypes circulating in different parts of the world. This study underscores the need for the continuous monitoring of dengue serotypes to predict potential outbreaks and mitigate the risk of severe dengue in susceptible populations.

In Vitro Determination of Antimicrobial, Antioxidant and Antiviral Properties of Greek Plant Extracts

The medicinal potential of plant extracts, especially their antimicrobial, antioxidant, antiviral and cytotoxic properties, has gained significant attention in recent years. This study examined the in vitro bioactivities of several selected Greek medicinal plants, like Eucalyptus globulus L., Thymus vulgaris L., Salvia rosmarinus L. and Ocimum basilicum L., are well-known for their traditional therapeutic use. Minimum inhibitory concentration (MIC) assays were used to evaluate the antimicrobial activity of the extracts against pathogenic bacteria. The antioxidant activity was carried out using the DPPH method, while the cytotoxicity of the plants was determined using the Alamar Blue method. In addition, the antiviral efficacy of the samples was tested against DENV in different cell lines. The majority of medicinal herbs demonstrated significant antimicrobial action (MIC = 30-3000 μg∙mL-1). The extracts showed great antioxidant activity, while the Salvia rosmarinus L. extract turned out to be the most effective (IC50 = 12.89 ± 0.11 μg∙mL-1). In contrast, the extract of Eucalyptus globulus L. had the lowest antioxidant action (IC50 = 71.02 ± 0.42 μg∙mL-1). The results of the Alamar Blue method were presented with CC50 values, and it was shown that Eucalyptus globulus L. extract exhibited the highest cytotoxicity (CC50 = 5.94% v/v ± 0.04). Similarly, the results of the antiviral potential of extracts were expressed as EC50 values, and Eucalyptus globulus L. was characterized as the most effective sample against dengue virus infection, with EC50 values estimated at 2.37% v/v ± 0.6 (HuhD-2 cells infected with DENV-2) and 0.36% v/v ± 0.004 (Huh7.5 cells infected with DVR2A). These findings provide a foundation for further studies in order to combat infectious diseases and promote human health.

A comprehensive review of research advances in the study of lactoferrin to treat viral infections

Lactoferrin (Lf) is a naturally occurring glycoprotein known for its antiviral and antibacterial properties and is present in various physiological fluids. Numerous studies have demonstrated its antiviral effectiveness against multiple viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza virus (IFV), herpes simplex virus (HSV), hepatitis B virus (HBV), and human immunodeficiency virus (HIV). Lf, a vital component of the mucosal defense system, plays a crucial role in inhibiting viral infection by binding to both host cells and viral particles, such as the Hepatitis C virus (HCV). This interaction enables Lf to keep viral particles away from their target cells, emphasizing its significance as a fundamental element of mucosal defense against viral infections. Additionally, Lf has the ability to modulate cytokine expression and enhance cellular immune responses. In the innate immune system, Lf serves as a unique iron transporter and helps suppress various pathogens like bacteria, fungi, and viruses. This article summarises the potential antiviral properties of Lf against various viruses, along with its other mentioned functions. The advancement of Lf-based therapies supports the homology of food and medicine, providing a promising avenue to address viral infections and other public health challenges.

Antimicrobial Peptides Against Arboviruses: Mechanisms, Challenges, and Future Directions

This review delves into the potential of antimicrobial peptides (AMPs) as promising candidates for combating arboviruses, focusing on their mechanisms of antiviral activity, challenges, and future directions. AMPs have shown promise in preventing arbovirus attachment to host cells, inducing interferon production, and targeting multiple viral stages, illustrating their multifaceted impact on arbovirus infections. Structural elucidation of AMP-viral complexes is explored to deepen the understanding of molecular determinants governing viral neutralization, paving the way for structure-guided design. Furthermore, this review highlights the potential of AMP-based combination therapies to create synergistic effects that enhance overall treatment outcomes while minimizing the likelihood of resistance development. Challenges such as susceptibility to proteases, toxicity, and scalable production are discussed alongside strategies to address these limitations. Additionally, the expanding applications of AMPs as vaccine adjuvants and antiviral delivery systems are emphasized, underscoring their versatility beyond direct antiviral functions.

Role of extracellular vesicles in the pathogenesis of mosquito-borne flaviviruses that impact public health

Mosquito-borne flaviviruses represent a public health challenge due to the high-rate endemic infections, severe clinical outcomes, and the potential risk of emerging global outbreaks. Flavivirus disease pathogenesis converges on cellular factors from vectors and hosts, and their interactions are still unclear. Exosomes and microparticles are extracellular vesicles released from cells that mediate the intercellular communication necessary for maintaining homeostasis; however, they have been shown to be involved in disease establishment and progression. This review focuses on the roles of extracellular vesicles in the pathogenesis of mosquito-borne flavivirus diseases: how they contribute to viral cycle completion, cell-to-cell transmission, and cellular responses such as inflammation, immune suppression, and evasion, as well as their potential use as biomarkers or therapeutics (antiviral or vaccines). We highlight the current findings concerning the functionality of extracellular vesicles in different models of dengue virus, Zika virus, yellow fever virus, Japanese encephalitis virus, and West Nile virus infections and diseases. The available evidence suggests that extracellular vesicles mediate diverse functions between hosts, constituting novel effectors for understanding the pathogenic mechanisms of flaviviral diseases.

Association of IL10 gene polymorphism with the susceptibility to dengue and disease severity in a population with asymptomatic and symptomatic dengue

Infections caused by Orthoflavivirus denguei can either manifest asymptomatically or present a wide spectrum of clinical manifestations. This variety of symptoms results from its complex pathogenesis, which is influenced by viral factors, in addition to host genetics and immunological factors. It is known that anti-inflammatory cytokines can play an immunomodulatory role throughout the course of dengue. Therefore, we investigated the single nucleotide polymorphisms (SNPs) -1082 A/G (rs1800896) and -819 C/T (rs1800871) in the interleukin-10 (IL10) gene and their possible relationship with the development of symptomatic dengue in a Brazilian population. This study, carried out in northeastern Brazil, involved 333 volunteers, including 74 patients with dengue without warning signs (DWWS), 45 patients with dengue with warning signs (DWAS), 85 patients with asymptomatic dengue infection (ASY) and 129 health controls. The genomic DNA was extracted and the SNPs were genotyped using quantitative real-time polymerase chain reaction (qPCR). The data obtained were used to conduct statistical analyses of the genotype and allele frequencies. We observed an association of A/G and G/G genotypes of the -1082 A/G SNP of the IL10 gene with susceptibility to symptomatic dengue and DWAS regarding the asymptomatic dengue. The G allele of this SNP has also been identified as a risk factor for symptomatic dengue, DWWS and DWAS. Regarding the analyses between the SNPs -1082 A/G and -819 C/T of the IL10 gene, there was an association of the G-C haplotype with symptomatic dengue, DWWS and DWAS, as well as a correlation of the A-C haplotype with asymptomatic dengue. Moreover, the data indicate an association between the presence of the G allele and the development of symptoms, compared to those without the G allele. Our results indicate the presence of the G allele of SNP -1082 A/G of the IL10 gene as a risk factor for the clinical development of symptomatic dengue in the studied population and show the importance of genomics association studies involving asymptomatic individuals.

Latin America's Dengue Outbreak Poses a Global Health Threat

Dengue fever, caused by the dengue virus (DENV), poses a significant global health challenge, particularly in tropical and subtropical regions. Recent increases in indigenous DENV cases in Europe are concerning, reflecting rising incidence linked to climate change and the spread of Aedes albopictus mosquitoes. These vectors thrive under environmental conditions like temperature and humidity, which are increasingly influenced by climate change. Additionally, global travel accelerates the cross-border spread of mosquito-borne diseases. DENV manifests clinically in a spectrum from asymptomatic cases to severe conditions like dengue hemorrhagic fever and dengue shock syndrome, influenced by viral serotype and host factors. In 2024, Brazil experienced a fourfold increase in dengue cases compared to 2023, accompanied by higher mortality. Conventional control measures, such as vector control, community engagement, and vaccination, proved insufficient as climate change exacerbated mosquito proliferation, challenging containment efforts. In this regard, our review analyzes prevention measures and therapeutic protocols during the outbreak while addressing DENV transmission dynamics, clinical presentations, and epidemiological shifts. It also evaluates diagnostic strategies combining clinical assessment with serological and molecular testing, providing information to improve diagnostic and preventive measures. The global expansion of dengue-endemic regions, including outbreaks in Europe, highlights the urgent need for enhanced surveillance, proactive interventions, and international collaboration to mitigate the growing threat of Dengue and other arboviruses like West Nile, Zika, Chikungunya, Oropouche, and Yellow Fever viruses.

Dominance of dengue virus serotype-2 in Pakistan (2023-2024): Molecular characterization of the envelope gene and exploration of antiviral targets

Dengue virus infection, caused by a single positive-stranded RNA virus from the Flaviviridae family, represents a significant public health challenge in tropical and subtropical regions. This virus has four serotypes (DENV-1, 2, 3, and 4), primarily transmitted by Aedes mosquitoes. Despite extensive research, effective antiviral treatments and vaccines remain elusive due to the viral diversity and the complex mechanisms such as antibody-dependent enhancement (ADE). In the current study, NS1-positive serum samples from dengue cases in Pakistan (2023-2024), were analyzed to determine the predominant serotype and characterize the envelope (E) gene for further exploration of antiviral targets. Out of 100 samples, 63 (63%) tested positive for DENV-2, indicating its predominance during this period, while two samples showed mixed infections with DENV-2 and DENV-3. The envelope gene was successfully amplified using nested PCR, validated through gel electrophoresis and sanger sequencing. Phylogenetic analysis revealed high similarity of the DENV-2 isolates to strains from China and India. Computational modeling of the envelope protein structure identified potential antiviral binding sites and further molecular docking studies suggested that specific antiviral compounds like Arbidol and Quercetin can inhibit early steps in viral infection. Additionally, BepiPred-3.0 predicted several B-cell epitopes, which could be useful for vaccine development. These findings enhance our understanding of dengue epidemiology in Pakistan and contribute to the development of targeted antiviral therapies, potentially informing future vaccination strategies and outbreak management.

Commercial Enzyme-Linked Immunosorbent Assay Kit Is Useful for Detection of Recombinant and Secretory Nonstructural-1 Protein Antigen of Dengue Virus

Background: Dengue is a mosquito-borne tropical disease, caused by the Dengue virus (DENV). It has become a severe problem and is a rising threat to public health. In this study, we have evaluated commercial Merilisa i Dengue NS1 Antigen kit (Meril LifeSciences India Pvt. Ltd.) to detect recombinant dengue virus 2 NS1 antigen (rDNS1Ag) and secreted forms of NS1 antigen (sDNS1Ag). Methods: To determine the detection limit of the kit, 100 nanogram (ng) to 0.001 ng rDNS1Ag was tested. The sensitivity and specificity of the kit was determined using recombinant NS1 antigens of all serotypes of DENV and other flaviviruses. For testing sDNS1Ag, the culture supernatant of the Vero cell lines infected with DENV-2 was tested. Further, a spiking experiment was carried out to check the sensitivity of the kit to detect rDNS1Ag in the pools of Aedes aegypti mosquitoes. Results: It was observed that the kit can detect the rDNS1Ag at 1 ng concentration. The kit was sensitive to detect NS1 antigen of DENV-1, DENV-2 and DENV-3 serotypes and specific for detection of only DNS1Ag as it did not cross-react with NS1 antigen of flaviviruses. The kit was sensitive to detect rDNS1Ag in the mosquito pools as well. In addition, the kit was able to detect the sDNS1Ag in Vero cell culture supernatant. Conclusions: Overall, we observed that the Merilisa i Dengue NS1 Ag kit is sensitive and specific for the detection of DNS1Ag both in recombinant and secretory forms.

Dengue fever in immunocompromised patients: A systematic review and meta-analysis

OBJECTIVES

Given the complex role of immunity in dengue severity, we aimed to review the clinical course of dengue infection in immunocompromised patients.

METHODS

We conducted a systematic review of studies reporting outcomes among immunocompromised patients with laboratory-confirmed dengue infection. Meta-analysis using the Mantel-Haenszel method (fixed effects) was performed for studies with control groups. We registered the study with PROSPERO (No. CRD42021258930).

RESULTS

We included 115 studies. Among these, 30 studies compared immunocompromised (cases) and nonimmunocompromised (control) patients, focusing mainly on children (n = 22 studies) with malnutrition (n=18). Immunocompromised patients had a higher likelihood of dengue complications (OR 1.87; 95% CI: 1.04-3.35]) but a lower likelihood of severe dengue (OR 0.83; 95% CI: 0.69-1.00]. No significant difference in mortality was observed. In the 85 studies focused solely on immunocompromised patients, severe dengue and mortality rates were 9% and 4%, respectively, mostly among adult solid organ transplant recipients and those with inflammatory diseases. Immunosuppressive treatment alterations and temporary graft dysfunction were reported.

CONCLUSION

Immunocompromised patients have an increased risk of dengue-related complications. However, definitive conclusions about the comparative severity of dengue across different immunocompromised patient groups are limited by a lack of robust data, highlighting the need for well-designed future studies.

Exploring plant-based dengue therapeutics: from laboratory to clinic

Dengue virus (DENV) is a mosquito-borne virus that causes dengue fever, a significant public health concern in many tropical and subtropical regions. Dengue is endemic in more than 100 countries, primarily in tropical and subtropical regions of the world. Each year, up to 400 million people get infected with dengue. Approximately 100 million people get sick from infection, and 40,000 die from severe dengue. Unfortunately, dengue vaccine development is also marred with various complicating factors, as the forefront candidate vaccine performed unsatisfactorily. Moreover, the only licensed vaccine (Dengvaxia) for children 9 through 16 years of age is available in just a few countries. The treatment difficulties are compounded by the absence of an effective antiviral agent. Exploring plant-based therapeutics for dengue from the laboratory to clinical application involves a multi-stage process, encompassing various scientific disciplines. Individual investigators have screened a wide range of plant extracts or compounds for potential antiviral activity against DENV. In vitro studies help identify candidates that exhibit inhibitory effects on viral replication. Some of the most promising medicinal plants showing in vitro activity against DENV include Andrographis paniculate, Acorus calamus, and Cladogynos orientalis. Further laboratory studies, both in vitro and in animal models (in vivo), elucidate the mechanisms of action by which the identified compounds exert antiviral effects. Medicinal plants such as Carica papaya, Cissampelos pareira, and Ipomea batata exhibited potent platelet-enhancing activities while Azadirachta indica and Curcuma longa showed promising effects in both in vitro and in vivo studies. Based on positive preclinical results, researchers design clinical trials. This involves careful planning of trial phases, patient recruitment criteria, ethical considerations, and endpoints. The most important medicinal plants showing efficacy and safety in clinical trials include Carica papaya and Cissampelos pareira. This review suggests that several promising medicinal plants exist that have the potential to be turned into clinical drugs to treat dengue infection. However, in addition to developing synthetic and plant-based therapies against dengue infection, vector management strategies should be made robust, emphasizing the need to focus on reducing disease incidence.

[Vaccinations for emerging and re-emerging viral diseases]

BACKGROUND

Emerging or re-emerging viral diseases have a pandemic potential and threaten global health. Vaccination is of crucial importance in the prevention of emerging and re-emerging viral diseases.

OBJECTIVE

Description of the current status of vaccine development against Filoviridae, highly pathogenic coronaviruses, smallpox viruses, influenza viruses and arboviruses.

MATERIAL AND METHODS

Focused literature search.

RESULTS

The World Health Organization (WHO) regularly publishes a list of infectious diseases that are expected to pose a major threat to humanity as they are could potentially trigger new pandemics; however, in addition to these human-to-human transmissible diseases, some arboviruses also have pandemic potential. In recent years numerous new vaccines, some of which are highly effective, have been licensed against new and re-emerging viral diseases and other promising vaccine candidates are currently in development.

CONCLUSION

There are still gaps in the development of vaccines in the area of Filoviridae and highly pathogenic coronaviruses. Vaccinations against smallpox viruses have been available for a long time. Developing influenza vaccines against novel strains in a timely manner is a challenge and universal influenza vaccines could be a possible solution. Modern vaccines are available against the arboviruses dengue and Chikungunya fever.

Lithospermic acid inhibits dengue virus infection through binding with envelope proteins

The dengue virus has emerged as a global pandemic, highlighting the urgent need for the immediate development of antiviral therapeutics. Lithospermum erythrorhizon, a medicinal plant commonly used in China for various ailments including viral infections, inflammation, rheumatism, and cancer, showed promising antiviral properties in our research. Specifically, both the ethanol extract of Lithospermum erythrorhizon and its active component, lithospermic acid, demonstrated significant inhibitory effects on Dengue virus (DENV) replication in Vero cells, with EC50 values of 6.50 μg/mL(95 % CI: 2.25 to 18.98)and 15.00 μM(95 % CI: 12.13 to 18.07), respectively. Notably, lithospermic acid exhibited potent antiviral activity across multiple cell lines against DENV, impeding virus replication and specifically impeding the expression of viral E and NS3 proteins during the early stages of DENV infection. Experimental assays involving RNase digestion and sucrose density gradient analysis confirmed that lithospermic acid did not directly inactivate DENV but rather interfered with viral processes. Furthermore, the compound was found to bind to the E protein of DENV, effectively inhibiting viral infection and mitigating the cytopathic effects induced by DENV. Collectively, these findings underscore the potential of lithospermic acid as a promising candidate for the development of therapeutic strategies targeting DENV infection.

Exploring Dengue Infection in a Vaccinated Individual: Preliminary Molecular Diagnosis and Sequencing Insights

This study examines a case involving a 7-year-old child who developed dengue symptoms following Qdenga vaccination. Despite initial negative diagnostic results, molecular analysis confirmed an infection with DENV4. Next-generation sequencing detected viral RNA from both DENV2 and DENV4 serotypes, which were identified as vaccine-derived strains using specific primers. Phylogenetic analysis further confirmed that these sequences belonged to the Qdenga vaccine rather than circulating wild-type viruses. This case underscores the critical need for precise diagnostic interpretation in vaccinated individuals to avoid misdiagnosis and to strengthen public health surveillance. A comprehensive understanding of vaccine-induced viremia is essential for refining dengue surveillance, improving diagnostic accuracy, and informing public health strategies in endemic regions.

Efficacy of human interleukin-11 analogs for treating dengue fever-associated thrombocytopenia: a prospective cohort

AIM

Dengue fever (DF), carried by Aedes mosquitoes, affects millions worldwide. Platelet-inducing human IL-11 analogues may be effective in treating DF-associated thrombocytopenia.

METHODOLOGY

A prospective study was done at Dr. Ziauddin Hospital, a tertiary care hospital in Karachi, Pakistan, from September 2023 to April 30, 2024.

RESULTS

This study recruited 300 DF patients characterized by thrombocytopenia (platelet count < 30,000), including 159 in the treatment and 141 in the control group. The median age of patients was 34 ± 11.05 years, with 187 males (62.3%) and 113 females (37.7%). The treatment group had a higher proportion of fever (80%, p < 0.0001) and headache (96%, p = 0.012) compared to the control group; however, no significant changes were observed in other clinical parameters between the two groups. Following treatment for 5 days, platelet counts of the treatment group increased significantly in response to IL-11 treatment compared to the control group at all time intervals (day 0, day 1, day 2, day 3, day 4, and day 5). Following treatment, males consistently exhibited higher platelet counts than females (all p < 0.05). In addition, patients admitted on day 3 of their course of illness showed a significantly slow response to the treatment compared to those admitted on day 5. Although young individuals exhibited a significant increase in platelet count, the age showed no significant intergroup differences.

CONCLUSIONS

IL-11 analogs have promising potential for treating DF-associated thrombocytopenia. Additional investigation is necessary to refine administration protocols and examine the wider therapeutic ramifications of IL-11 in managing DF.

Immunization of recombinant NS3 protein (protease region) of dengue virus induces high levels of CTLA-4 and apoptosis in splenocytes of BALB/c mice

DENV infection outcomes depend on the host's variable expression of immune receptors and mediators, leading to either resolution or exacerbation. While the NS3 protein is known to induce robust immune responses, the specific impact of its protease region epitopes remains unclear. This study investigated the effect of recombinant NS3 protease region proteins from all four DENV serotypes on splenocyte activation in BALB/c mice (n = 5/group). Mice were immunized with each protein, and their splenocytes were subsequently stimulated with homologous antigens. We measured the expression of costimulatory molecules (CD28, CD80, CD86, CD152) by flow cytometry, along with IL-2 production, CD25 expression, and examined the antigen-specific activation of CD4 + and CD8 + T cells. Additionally, the expression of IL-1, IL-10, and TGF-β1 in splenocytes from immunized animals was assessed. Apoptosis was evaluated using Annexin V/PI staining and DNA fragmentation analysis. Stimulation of splenocytes from immunized mice triggered apoptosis (phosphatidylserine exposure and caspase 3/7 activation) and increased costimulatory molecule expression, particularly CD152. Low IL-2 production and low CD25 expression, as well as sustained expression of the IL-10 gene. These results suggest that these molecules might be involved in mechanisms by which the NS3 protein contributes to viral persistence and disease pathogenesis.

Blood components requirement in Brazilian dengue outbreaks: A retrospective analysis between 2008 to 2019

INTRODUCTION

Dengue is the most fatal virus disease spread by mosquito bites and Aedes aegypti is the main transmitting agent. It is an endemic disease in the tropical and subtropical regions, currently affecting more than 100 countries. Although most patients present mild forms of the disease, a considerable proportion of individuals has severe alterations in the blood count. The aim of this study was to evaluate the consumption pattern of blood components in epidemic and non-epidemic periods and to verify if there was an impact on dengue cases and the death rate.

METHOD

This is a retrospective cross-sectional study conducted through the collection and analysis of data from the Brazilian Ministry of Health from 2008 to 2019 on new cases and deaths from dengue, as well as the consumption of blood components in the period mentioned by hemovigilance bulletins of the Brazilian authority.

RESULTS

Regarding the results, no significant difference was found between the absolute amount of blood components used in years with an epidemic peak. Regarding the relative values, an important variation was shown among the distributive consumption patterns of blood components in the outbreak years. In the univariate linear regression analysis, there was statistical significance between the increase in the number of dengue cases and deaths from dengue with the increase in the consumption of red blood cell concentrates (RBP), platelet concentrates (PP), fresh frozen plasma (FFP) and cryoprecipitate (Cryo) (p-value < 0.05). The increase in dengue cases was related to the increase in Cryo consumption with clinical significance (R² > 0.5), but dengue deaths were not correlated to the same. In multivariate analysis, all regression models had clinical and statistical significance.

CONCLUSION

The data obtained in the present study demonstrate that there is a relevant relationship between the increase in cases and deaths from dengue with the blood components usage, especially PP, FFP and cryoprecipitate.

Computational design, docking, and molecular dynamics simulation study of RNA helicase inhibitors of dengue virus

BACKGROUND OBJECTIVES

RNA viruses are complex pathogens in terms of their genetic makeup, mutation frequency, and transmission modes. They contain the RNA helicase enzyme, which plays a crucial role in the viral genome replication process. This work aims to develop and screen a potential molecule that could function as a dengue virus (DENV) RNA helicase inhibitor.

METHODS

The present study was performed by taking 26 potential derivatives of gedunin phytochemicals from the PubChem database as ligands. The binding of the compounds was analyzed by in silico docking considering DENV RNA helicase enzyme as the receptor.

RESULTS

After a thorough analysis of the docking scores, toxicity, and physicochemical properties, the compound tetrahydrogedunin was obtained as the best. Based on tetrahydrogedunin molecular structure, 100 drug-like molecules were designed using the Data Warrior tool. After screening for drug-likeness and ADMET properties, derivative number 42 was considered as promising. Further comparative docking of derivative 42 and a standard inhibitor molecule ST-610 with DENV RNA helicase enzyme showed binding affinity of 10.0 kcal/mol and -9.6 kcal/mol, respectively. The favorable interaction between DENV RNA helicase and derivative 42 was further validated by 50 nanoseconds molecular dynamics simulation and MM-GBSA analysis.

INTERPRETATION CONCLUSION

Since the antiviral activity of derivative 42 has not been reported till date, the compound was predicted as a novel therapeutic molecule that can act against the dengue virus (DENV) RNA helicase enzyme.

Computational Screening to Predict MicroRNA Targets in the Flavivirus 3' UTR Genome: An Approach for Antiviral Development

MicroRNAs (miRNAs) are molecules that influence messenger RNA (mRNA) expression levels by binding to the 3' untranslated region (3' UTR) of target genes. Host miRNAs can influence flavivirus replication, either by inducing changes in the host transcriptome or by directly binding to viral genomes. The 3' UTR of the flavivirus genome is a conserved region crucial for viral replication. Cells might exploit this well-preserved region by generating miRNAs that interact with it, ultimately impacting viral replication. Despite significant efforts to identify miRNAs capable of arresting viral replication, the potential of all these miRNAs to interact with the flavivirus 3' UTR is still poorly characterised. In this context, bioinformatic tools have been proposed as a fundamental part of accelerating the discovery of interactions between miRNAs and the 3' UTR of viral genomes. In this study, we performed a computational analysis to reveal potential miRNAs from human and mosquito species that bind to the 3' UTR of flaviviruses. In humans, miR-6842 and miR-661 were found, while in mosquitoes, miR-9-C, miR-2945-5p, miR-11924, miR-282-5p, and miR-79 were identified. These findings open new avenues for studying these miRNAs as antivirals against flavivirus infections.

In vitro analysis of VEGF-mediated endothelial permeability and the potential therapeutic role of Anti-VEGF in severe dengue

Background

Vascular endothelial growth factor (VEGF) is one of the proteins involved in dengue immunopathogenesis. It is overexpressed in severe dengue and contributes to vascular permeability and plasma leakage. In this study, we investigated the effects of VEGF and anti-VEGF treatments on endothelial cells in vitro, to assess the potential use of anti-VEGF antibodies in managing severe dengue.

Methods

Human pulmonary microvascular endothelial cells were treated with VEGF and a VEGF/anti-VEGF combination. The effects of the treatments were studied using an endothelial permeability assay and microarray gene expression profiling. In the permeability assay, the fluorescein isothiocyanate (FITC)-dextran fluorescence signal across the endothelial monolayer was recorded, and the cells were stained with PECAM-1 to detect gap formation. RNA was extracted from treated cells for microarray gene profiling and analysis. The results were analyzed for differentially expressed genes (DEGs) and gene enrichment analysis. The DEGs were subjected to STRING to construct the protein-protein interaction network and then Cytoscape to identify the hub genes.

Results

VEGF-treated endothelial cells showed greater movement of FITC-dextran across the monolayer than VEGF/anti-VEGF-treated cells. There were 111 DEGs for VEGF-treated cells and 118 DEGs for VEGF/anti-VEGF-treated cells. The genes upregulated in VEGF-treated cells were enriched in inflammatory responses and regulation of the endothelial barrier, nitric oxide synthesis, angiogenesis, and the nucleotide-binding oligomerization domain-like receptor signaling pathway. Top 10 hub genes were identified from the DEGs.

Conclusions

VEGF treatment increased permeability across endothelial cells, while anti-VEGF reduced this leakage. Analysis of VEGF-treated endothelial cells identified hub genes implicated in severe dengue. The top 10 hub genes were TNF, IL1B, IL6, CCL2, PTGS2, ICAM1, CXCL2, CXCL1, CSF2, and TLR2. The results of this study show that using anti-VEGF antibodies to neutralize VEGF may be a promising therapy to prevent the progression of dengue to severe dengue.

Diagnostic accuracy of Dengue NS1 lateral flow immunoassay in comparison to reverse transcriptase polymerase chain reaction and enzyme linked Immunosorbent Assay

The most widely used invitro diagnostic qualitative screening method for dengue virus infection is the lateral flow immunoassay technique. Testing of dengue non-structural antigen NS1 offers specificity in determining the active infection while testing of IgM and IgG helps in differentiating the primary and secondary dengue infections. The ELISA functions as the golden standard for dengue testing and PCR credits for the most accurate determination tool at the genetic level. The RT-PCR endorsed NS1 gene and in ELISA or LFIA NS1 antigen is used as the marker owing to the specificity and lesser chances of mutation effects. This study evaluated the performance of AG-Q Dengue NS1 LFIA kit in comparison with RT-PCR quantification cycle (Cq) Values and ELISA NS1 quantitation. The study also focused on differentiating the samples among dengue serotypes using the RealStar Dengue Type RT-PCR Kit 1.0. Dengue serotype 2 is the prominent viral strain in Kerala region succeeded by serotype 3 and 1 with a prevalence rate of 64 %, 20 % and 6 % respectively. Dengue serotype 4 was not reported during this study period. 10 % co-infection with DENV 1 & DENV 2 was also reported. The AG-Q Dengue NS1 kit stood as efficient in screening by providing positive results with samples having RT-PCR Cq values up to 43 and ELISA NS1 quantification minimum of 14 Panbio units.