Mosquito-borne Viral Disease Research Articles

Exploring the Targets of Dengue Virus and Designs of Potential Inhibitors.

Dengue, a mosquito-borne viral disease spread by the dengue virus (DENV), has become one of the most alarming health issues in the global scenario in recent days. The risk of infection by DENV is mostly high in tropical and subtropical areas of the world. The mortality rate of patients affected with DENV is ever-increasing, mainly due to a lack of anti-dengue viral-specific synthetic drug components. Repurposing synthetic drugs has been an effective tool in combating several pathogens, including DENV. However, only the Dengvaxia vaccine has been developed so far to fight against the deadly disease despite the grave situation, mainly because of the limitations of understanding the actual pathogenicity of the disease. To address this particular issue and explore the actual disease pathobiology, several potential targets, like three structural proteins and seven non-structural (NS) proteins, along with their inhibitors of synthetic and natural origin, have been screened using docking simulation. Exploration of these targets, along with their inhibitors, has been extensively studied in culmination with molecular docking-based screening to potentiate the treatment. These screened inhibitors could possibly be helpful for the designing of new congeneric potential compounds to combat dengue fever and its complications.

Methodological framework for early detection of dengue outbreaks in Tanzania

Abstract Background Dengue fever is a major public health problem because it is a widespread and rapidly transmitted mosquito-borne viral disease. We developed a framework for early detection of dengue outbreaks in Tanzania, starting with detection of suspected and/or confirmed cases, followed by site-specific risk characterization, both useful for planning and prioritizing outbreak interventions or epidemic preparedness. Methods Our initial focus was on the identification and categorization of indicators that are specifically tailored to the early detection and classification of outbreak events. The framework was then evaluated using (i) available cases with syndromic and laboratory-confirmed disease information from ProMED emails using decision tree analysis, and (ii) available historical dengue epidemic data at the local level from 2019 with 6,795 confirmed cases using negative binomial regression analysis adjusted for month and area. Results The laboratory-confirmed diagnosis (dengue yes or no) was consistent with the results of the suspected case classification algorithm for clinically defined syndromic cases. There was strong evidence of an increase in dengue cases with higher site-specific risk (rate ratio = 2.51 (95% CI = [1.76, 3.58])) when regressing confirmed dengue cases in 2019 as the dependent variable and site-specific risk as the independent variable. Conclusions The rapid dengue outbreak risk assessment developed may be useful in controlling the epidemic in Tanzania. The suspected case classification algorithm can be a very useful tool to better assess whether a potential dengue case is present and thus requires laboratory confirmation. The framework can be used to rapidly predict the risk of dengue outbreaks, which is useful for planning and prioritizing interventions or for epidemic preparedness. Key messages • Framework for a novel rapid risk assessment for early detection of dengue outbreaks in Tanzania. • Framework relevant to epidemic preparedness.

Serotype-specific epidemiological patterns of inapparent versus symptomatic primary dengue virus infections: a 17-year cohort study in Nicaragua.

Dengue is the most prevalent mosquito-borne viral disease and a major public health problem worldwide. Most primary infections with the four dengue virus serotypes (DENV1-4) are inapparent; nonetheless, whether the distribution of symptomatic versus inapparent infections by serotype varies remains unknown. Here, we present (1) the evaluation of a DENV1-4 envelope domain III multiplex microsphere-based assay (EDIII-MMBA) to serotype inapparent primary infections and (2) its application leveraging 17 years of prospective sample collection from the Nicaraguan Pediatric Dengue Cohort Study (PDCS). We analysed primary DENV infections in the PDCS from 2004 to 2022 detected by inhibition ELISA (iELISA) or RT-PCR. First, we evaluated the performance of the EDIII-MMBA for serotyping with samples characterised by RT-PCR or focus reduction neutralisation test. Next, we analysed a subset of inapparent primary DENV infections in the PDCS with the EDIII-MMBA to evaluate the epidemiology of inapparent infections. Remaining infections were inferred using stochastic imputation, taking year and neighbourhood into account. Infection incidence and percentage of inapparent, symptomatic, and severe infections were analysed by serotype. Between Aug 30, 2004, and March 10, 2022, a total of 5931 DENV-naive participants were followed in the PDCS. There were 1626 primary infections (382 symptomatic, 1244 inapparent) detected by iELISA or RT-PCR over the study period. The EDIII-MMBA demonstrated excellent overall accuracy (100%, 95% CI 95·8-100) for serotyping inapparent primary DENV infections when evaluated against gold-standard serotyping methods. Of the 1244 inapparent infections, we analysed 574 (46%) using the EDIII-MMBA. We found that the majority of primary infections were inapparent, with DENV3 exhibiting the highest likelihood of symptomatic (pooled odds ratio compared with DENV1: 2·13, 95% CI 1·28-3·56) and severe (6·75, 2·01-22·62) primary infections, whereas DENV2 was similar to DENV1 in both analyses. Considerable within-year and between-year variation in serotype distribution between symptomatic and inapparent infections and circulation of serotypes undetected in symptomatic cases were observed in multiple years. Our study indicates that case surveillance skews the perceived epidemiological footprint of DENV. We reveal a more complex and intricate pattern of serotype distribution in inapparent infections. The substantial differences in infection outcomes by serotype emphasises the need for vaccines with balanced immunogenicity and efficacy across serotypes. National Institute of Allergy and Infectious Diseases (National Institutes of Health) and Bill & Melinda Gates Foundation. For the Spanish translation of the abstract see Supplementary Materials section.

Ecological features and insecticide resistance of Aedes albopictus in Xi'an, a high-risk dengue transmission area in China.

Dengue, a mosquito-borne viral disease, has occurred in many cities in China, and it tends to spread to higher latitudes (Huang et al., 2023). Xi'an, situated in central-west China, has witnessed an increase imported cases in the past few years, raising concerns of local dengue transmission. It is crucial to investigate the population density of Aedes albopictus and its insecticides resistance to enhance early warning of dengue fever. Eight sampling sites in eight counties (YT, BL, WY, CH, YL, LN, LT, ZZ) of Xi'an city were surveyed by larval dipping and human-baited double net trap biweekly from June 2021 to September 2022. The Breteau Index (BI, number of positive containers per 100 houses) and Container Index (CI, the percentage of containers containing larvae or pupae) were used to assess larval density, and the human-baited double net trap (HDN, the number of Ae. albopictus females collected per person per hour) to indicate human bating rate (HBR). Meanwhile, the association between the meteorological factors and mosquito density was analyzed. The Ae. albopictus adult insecticides resistance was evaluated by the World Health Organization (WHO) standard resistance bioassay. Adult females were exposed to insecticide-impregnated paper for 1 h, then transferred to the recovery tube, and mortality rate was calculated after 24 h. According to the Implementation Plan for National Vector Surveillance (2016), resistance status was classified into three levels based on mortality: <80% mortality as resistant, between 80% and 98% mortality as possibly resistant, and >98% mortality as sensitive. From June 2021 to September 2022, a total of 1,065 houses were surveyed for water holding containers, and 99 of 430 water holding containers were checked to be positive for Ae. albopictus larvae and pupae. A total of 1,048 Ae. albopictus females were collected. The average BI, CI and HBR were 10.39, 21.41, and 11.20 female/man/hour in 2021 and 8.86, 20.86, and 11.63 f/m/h in 2022, respectively. The findings showed that the BI exceeded 5 in most months and reached above 20 in specific months. The CI varied in different months and monitoring sites, with the highest CI in August 2021 and July 2022. The discarded tires had the highest positivity rate, with up to 40.32% testing positive for Ae. albopictus larvae. The monthly average temperature showed a positive correlation with CI (r = 0.77), and the monthly BI was positively associated with CI (r = 0.93). The BI, CI, and HBR were significantly higher in the rainy season than other seasons. The bioassay results showed that the mortality rate of Ae. albopictus at the YT monitoring site was 76.92%, indicating resistance to deltamethrin. The mortality rate of Ae. Albopictus at BL, WY, CH, YL, LN, LT, and ZZ sampling sites were varying from 81.25%∼100%, suggesting possibly resistant or still sensitive to beta-cypermethrin, alpha-cypermethrin, malathion, chlorpyrifos, and propoxur.

An Integrated Approach for Development of a Decision Support System for Early Surveillance of Japanese Encephalitis: a Remote Sensing-based study in Conjunction with Epidemiological Scenario in Assam, India

Abstract. Japanese Encephalitis (JE) is one of the serious mosquito borne viral diseases mostly prevalent in India and many of the South Asian countries. A comprehensive study was conducted in Dibrugarh, a JE endemic district of Assam taking into the account of the environmental and social factors that determine the outbreak of the disease. Effect of environmental and climatic factors on mosquito vector densities was investigated using geospatial tools and techniques. Wetlands were found to be the most preferred habitat type for most of the JE-transmitting mosquitoes followed by paddy-growing areas and ponds. The villages abundant with these habitats or located nearby were found to be more vulnerable to JE risk. Based on the spatial distribution of habitat types, villages in the district were divided into three categories of vector abundance and hence the risk of JE. It is found that rainfall (intensity as well as duration) is the most significant determinant in the modulation of mosquito density followed by temperature. It is also observed that the derived models could explain about 61% to 73% variation in mosquito density due to change in weather variables as indicated by R2 values of the Models. Among socio-economic determinants, pig rearing habit of the villagers was found to be most significant. JE risk map was prepared by integrating vector abundance map with the map of host abundance in GIS domain. Attempts were also made to forecast the intensity of JE cases based on a time series analysis of historical morbidity pattern, whereas forecast for onset of the disease was based on the modulation of weather variables in the study area. A web-based decision support system (DSS) developed by integrating the forecasts of JE onset, intensity and JE prone villages has been provided to the concerned health authorities to take timely intervention measures. The JE early warning system developed for Dibrugarh district was extended to two more JE prone districts viz, Sibsagar and Tinsukia as validation sites and observed that the accuracy of forecast was within the range of 69% to 77%. DSS on JE has opened up new opportunities to study similar vector-borne diseases of the JE serogroup viz., West Nile.

A Review of Nonhuman Primate Models of Rift Valley Fever Virus Infection: Progress, Challenge Strains, and Future Directions.

Rift Valley fever (RVF) is a mosquito-borne viral disease that primarily affects animals, especially ruminants, but has the capacity to infect humans and result in outbreaks. Infection with the causative agent, RVF virus (RVFV), causes severe disease in domestic animals, especially sheep, resulting in fever, anorexia, immobility, abortion, and high morbidity and mortality rates in neonate animals. Humans become infected through exposure to infected animals and, less frequently, directly via a mosquito bite. A greater awareness of RVFV and its epidemic potential has resulted in increased investment in the development of interventions, especially vaccines. There is currently no substitute for the use of animal models in order to evaluate these vaccines. As outbreaks of RVF disease are difficult to predict or model, conducting Phase III clinical trials will likely not be feasible. Therefore, representative animal model systems are essential for establishing efficacy data to support licensure. Nonhuman primate (NHP) species are often chosen due to their closeness to humans, reflecting similar susceptibility and disease kinetics. This review covers the use of NHP models in RVFV research, with much of the work having been conducted in rhesus macaques and common marmosets. The future direction of RVF work conducted in NHP is discussed in anticipation of the importance of it being a key element in the development and approval of a human vaccine.

A study on correlation of liver function tests and outcome in patients of dengue

Dengue, a mosquito-borne viral disease, presents a significant public health threat, particularly in tropical and subtropical regions. This study aims to assess the correlation between elevated serum aminotransferases and dengue severity, focusing on patients at a tertiary care center. The liver is affected to varying degrees in dengue patients, from asymptomatic enzyme elevation to severe hepatitis. The study found that elevated SGOT levels correlate with more severe symptoms, including prolonged fever, abdominal pain, and bleeding manifestations.

Infection Epidemiology of Dengue Virus and Its Impacts on Liver Enzymes

Background: Dengue fever is a mosquito-borne viral disease that has emerged as a significant public health concern in Kolkata, with a substantial burden on the healthcare system. Also, this disease shows and additional impact on liver. Objective: To investigate the epidemiological trends of dengue fever in Kolkata and its effect on liver function. Methods: A retrospective study was conducted using data from [Ashok Laboratory] in Kolkata. Patients diagnosed with dengue fever between [July, 2023 to June, 2024] were included. Demographic, clinical, and laboratory data were analyzed. Results: A total of [6132] patients were included. The majority were [10-30] years old, and [males]. The incidence of dengue fever was highest during [monsoon season]. The data shows that SGPT/ALT and SGOT/AST value is very high on the dengue positive individuals and total bilirubin value is also high on dengue positive individuals. Conclusion: This study highlights the significant impact of dengue fever on liver function in Kolkata. The findings suggest that early detection and management of dengue-induced hepatic dysfunction are crucial to prevent severe complications. Public health measures should focus on vector control, timely diagnosis, and appropriate treatment to mitigate the burden of dengue fever in Kolkata.

Quantification of the interaction forces between dengue virus and dopamine type-2 receptor using optical tweezers

BackgroundDengue virus (DENV) causes the most significant mosquito-borne viral disease with a wide spectrum of clinical manifestation, including neurological symptoms associated with lethal dengue diseases. Dopamine receptors are expressed in central nervous system, and dopamine antagonists have been reported to exhibit antiviral activity against DENV infection in vivo and in vitro. Although identification of host-cell receptor is critical to understand dengue neuropathogenesis and neurotropism, the involvement of dopamine receptors in DENV infection remains unclear.ResultsWe exploited the sensitivity and precision of force spectroscopy to address whether dopamine type-2 receptors (D2R) directly interact with DENV particles at the first step of infection. Using optical tweezers, we quantified and characterized DENV binding to D2R expressed on Chinese hamster ovary (CHO) cells. Our finding suggested that the binding was D2R- and DENV-dependent, and that the binding force was in the range of 50–60 pN. We showed that dopamine antagonists prochlorperazine (PCZ) and trifluoperazine (TFP), previously reported to inhibit dengue infection, interrupt the DENV-D2R specific binding.ConclusionsThis study demonstrates that D2R could specifically recognize DENV particles and function as an attachment factor on cell surfaces for DENV. We propose D2R as a host receptor for DENV and as a potential therapeutic target for anti-DENV drugs.Graphical abstract

Employing Machine Learning-Based QSAR for Targeting Zika Virus NS3 Protease: Molecular Insights and Inhibitor Discovery.

Zika virus infection is a mosquito-borne viral disease that has become a global health concern recently. Zika virus belongs to the Flavivirus genus and is primarily transmitted by Aedes mosquitoes. Prevention of Zika virus infection involves avoiding mosquito bites by using repellent, wearing protective clothing, and staying in screened areas, especially for pregnant women. Treatment focuses on managing symptoms with rest, fluids, and acetaminophen, with close monitoring for pregnant women. Currently, there is no specific antiviral treatment or vaccine for the Zika virus, highlighting the importance of prevention strategies to control its spread. Therefore, in this study, the Zika virus non-structural protein NS3 was targeted to inhibit Zika infection by identifying the novel inhibitor through an in silico approach. Here, 2864 natural compounds were screened using a machine learning-based QSAR model, and later docking was performed to select the potential target. Subsequently, Tanimoto similarity and clustering were performed to obtain the potential target. The three most potential compounds were obtained: (a) 5297, (b) 432449, and (c) 85137543. The protein-ligand complex's stability and flexibility were then investigated by dynamic modelling. The 300 ns simulation showed that 5297 exhibited the steadiest deviation and constant creation of hydrogen bonds. Compared to the other compounds, 5297 demonstrated a superior binding free energy (ΔG = -20.81 kcal/mol) with the protein when the MM/GBSA technique was used. The study determined that 5297 showed significant therapeutic potential and justifies further experimental investigation as a possible inhibitor of the NS2B-NS3 protease target implicated in Zika virus infection.

Primary Dengue and Long-Term Health Status in Madeira Island, Portugal: A Retrospective Questionnaire-Based Study.

Dengue is among the most important mosquito-borne viral diseases worldwide. Although its acute manifestations are well known, little is known about the long-term impact of dengue on the population's health status. Madeira Island experienced a single outbreak of autochthonous dengue from September 2012 to March 2013. To extend our knowledge about the clinical impact of the outbreak on this naive population, we applied an online questionnaire to 168 adults diagnosed with dengue at the time to characterize retrospectively their symptoms during the infection and to identify long-term manifestations, possibly triggered by dengue. The most frequent symptoms during the clinical period, reported by more than three-quarters of our participants, were fever, myalgia, extreme tiredness, and headaches, whereas vomiting, pruritus, nausea, retro-orbital pain, and arthralgia occurred in 35% to 50% of participants. In the 8 years after dengue, 61.5% of participants reported at least one recurrent previously nonexistent symptom, the most frequent being headaches, abundant hair loss, extreme tiredness, arthralgia, and myalgia, experienced by 25% to 35% of participants. Nearly 20% of the participants with persistent symptoms reported the onset of chronic illness in the 4 years after dengue, most frequently ophthalmological and autoimmune diseases (5.6% each), versus only 2.2% of chronic disease onset in participants without persistent symptoms. Our results suggest that the occurrence of persistent symptoms after primary dengue might be more frequent than anticipated and may persist for several years, having an impact on the health status and well-being of a considerable proportion of the infected population.

Impact of Waste Management on Infectious Disease Control: Evaluating Strategies to Mitigate Dengue Transmission and Mosquito Breeding Sites – A Systematic Review

Background: Dengue, a mosquito-borne viral disease primarily transmitted by Aedes mosquitoes, is a significant global public health concern, particularly in tropical and subtropical regions. Severe cases, including dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), can be fatal. Recent outbreaks in Bangladesh highlight the disease's escalating threat, with inadequate waste management playing a critical role in mosquito breeding and disease transmission. Methods: This review aims to assess the effectiveness of various waste management techniques, such as gasification, pyrolysis, compaction, and incineration, in reducing the buildup of garbage and, therefore, the spread of mosquito breeding grounds. This review also assesses the waste-derived containers used for storing wastewater, which act as breeding grounds for dengue mosquitoes. This review identifies Aedes aegypti mosquito larvae density in ten dengue-endemic regions. Larval samples were collected from various outdoor containers using dipping methods and analyzed through the Container Index (CI). The CI represents the percentage of containers infested with larvae and indicates the potential for dengue transmission. Results: The review revealed that high CI values in locations such as Dire Dawa, Ethiopia (54%), and Tamil Nadu, India (32.2%) indicated significant risk for dengue transmission. In contrast, a low CI value of 0.15% was observed in Rawalpindi, Pakistan, corresponding with lower dengue incidence. Results showed that poorly managed waste sites, particularly those accumulating stagnant water, contributed to higher CI values. Conclusion: Effective waste management, including proper disposal and reduced breeding grounds, is crucial in mitigating dengue transmission. The review emphasizes the need for improved waste management infrastructure, community involvement, and government-led policy frameworks to control Aedes mosquito populations and reduce dengue outbreaks.

Serotype-Specific Epidemiological Patterns of Inapparent versus Symptomatic Primary Dengue Virus Infections: A 17-year cohort study in Nicaragua.

Dengue is the most prevalent mosquito-borne viral disease and a major public health problem worldwide. Most primary infections with the four dengue virus serotypes (DENV1-4) are inapparent; nonetheless, whether the distribution of symptomatic versus inapparent infections by serotype varies remains unknown. Here, we present (1) the evaluation of a multiplex DENV1-4 envelope domain III multiplex microsphere-based assay (EDIII-MMBA) to serotype inapparent primary infections and (2) its application leveraging 17 years of prospective sample collection from the Nicaraguan Pediatric Dengue Cohort Study (PDCS). First, we evaluated the performance of the EDIII-MMBA with samples characterized by RT-PCR or focus reduction neutralization test. Next, we analyzed 46% (N=574) of total inapparent primary DENV infections in the PDCS with the EDIII-MMBA to evaluate the epidemiology of inapparent infections. Remaining infections were inferred using stochastic imputation, taking year and neighborhood into account. Infection incidence and percentage of inapparent, symptomatic, and severe infections were analyzed by serotype. The EDIII-MMBA demonstrated excellent overall accuracy (100%, 95.8-100%) for serotyping symptomatic and inapparent primary DENV infections when evaluated against gold-standard serotyping methods. We found that a significant majority of primary infections were inapparent, with DENV3 exhibiting the highest likelihood of symptomatic and severe primary infections (Pooled OR compared to DENV1 = 2.13, 95% CI 1.28-3.56, and 6.75, 2.01-22.62, respectively), whereas DENV2 was similar to DENV1 in both analyses. Significant within- and between-year variation in serotype distribution between symptomatic and inapparent infections and circulation of serotypes undetected in symptomatic cases were observed in multiple years. Our study indicates that case surveillance skews the perceived epidemiological footprint of DENV. We reveal a more complex and intricate pattern of serotype distribution in inapparent infections. The significant differences in infection outcomes by serotype emphasizes the need for vaccines with balanced immunogenicity and efficacy across serotypes.

Distinct Pathological Changes in Preweaning Mice Infected with Live-Attenuated Rift Valley Fever Virus Strains.

Rift Valley fever (RVF) is a mosquito-borne zoonotic viral disease endemic to Africa and the Middle East. Live-attenuated RVF vaccines have been studied for both veterinary and human use due to their strong immunogenicity and cost-effective manufacturing. The live-attenuated MP-12 vaccine has been conditionally approved for veterinary use in the U.S.A., and next-generation live-attenuated RVF vaccine candidates are being actively researched. Assessing the virulence phenotype of vaccine seeds or lots is crucial for managing vaccine safety. Previously, preweaning 19-day-old outbred CD1 mice have been used to evaluate the MP-12 strain. This study aimed to characterize the relative virulence of three live-attenuated RVF vaccine strains in 19-day-old inbred C57BL/6 mice: the recombinant MP-12 (rMP-12), the RVax-1, and the ∆NSs-∆NSm-rZH501 strains. Although this mouse model did not show dose-dependent pathogenesis, mice that succumbed to the infection exhibited distinct brain pathology. Mice infected with ∆NSs-∆NSm-rZH501 showed an infiltration of inflammatory cells associated with infected neurons, and focal lesions formed around virus-infected cells. In contrast, mice infected with rMP-12 or RVax-1 showed a minimal association of inflammatory cells in the brain, yet the virus spread diffusely. The preweaning model is likely useful for evaluating host responses to attenuated RVFV strains, although further refinement may be necessary to quantitate the virulence among different RVFV strains or vaccine lots.

Serotype and genomic diversity of dengue virus during the 2023 outbreak in Pakistan reveals the circulation of genotype III of DENV-1 and cosmopolitan genotype of DENV-2.

Dengue, a mosquito-borne viral disease, poses a significant public health challenge in Pakistan, with a significant outbreak in 2023, prompting our investigation into the serotype and genomic diversity of the dengue virus (DENV). NS-1 positive blood samples from 153 patients were referred to the National Institute of Health, Pakistan, between Julyand October 2023. Among these, 98 (64.1%) tested positive using multiplex real-time PCR, with higher prevalence among males (65.8%) and individuals aged 31-40. Serotyping revealed DENV-1 as the predominant serotype (84.7%), followed by DENV-2 (15.3%). Whole-genome sequencing of 18 samples (DENV-1 = 17, DENV-2 = 01) showed that DENV-1 (genotype III) samples were closely related (>99%) to Pakistan outbreak samples (2022), and approx. > 98% with USA (2022), Singapore and China (2016), Bangladesh (2017), and Pakistan (2019). The DENV-2 sequence (cosmopolitan genotype; clade IVA) shared genetic similarity with Pakistan outbreak sequences (2022), approx. > 99% with China and Singapore (2018-2019) and showed divergence from Pakistan sequences (2008-2013). No coinfection with dengue serotypes or other viruses were observed. Comparisons with previous DENV-1 sequences highlighted genetic variations affecting viral replication efficiency (NS2B:K55R) and infectivity (E:M272T). These findings contribute to dengue epidemiology understanding and underscore the importance of ongoing genomic surveillance for future outbreak responses in Pakistan.

Physico-chemical characteristics of breeding habitats in relation to larval density and relative abundance of Aedes mosquitoes from Siliguri sub-division, West Bengal, India

Aim: Characterization of physico-chemical parameters of Aedes mosquito breeding habitats from dengue-endemic Siliguri sub-divisional area and correlation of larval density with the habitat characteristics. Methodology: Natural and artificial water-holding containers found in four blocks, namely- Naxalbari, Matigara, Khoribari and Phansidewa of Siliguri sub-divisional area were surveyed for the collection of Aedes mosquito larvae. Water parameters such as pH, temperature, electric conductance (EC), total dissolved solid (TDS), chloride, salinity, total hardness (TH) and dissolved oxygen (DO) were measured and the larval density (LD) indices and relative abundance for Aedes spp., were calculated. Results: Out of 40 habitats, larvae of Aedes spp. were found in 20 habitats (50%). Ae. albopictus was found as the pre-dominant species (81.24%) in all the positive breeding habitats. Three habitat characteristics, like chloride (r= -0.959; p= 0.041), salinity (r= -0.958; p= 0.041)and TH (r= -0.961; p= 0.039) showed significant negative association with larval densityin the study. Whereas the remaining parameters, like-pH, temperature, EC, TDS, were positively correlated and DO showed a negative correlation with larval density. Although none of the later correlations were statistically significant. The larval density of Aedes spp. (mean ± SD) was lowest in Khoribari (27.66 ± 21.55) and highest in Phansidewa block (128.33 ± 187.26). Interpretation: Pre-dominance of Ae. albopictus reiterates its importance as a principal dengue vectorin rural, peri- or sub-urban area of the sub-division. Utilizing the obtained data, the efficacy of oviposition traps can be enhanced for locale-specific vector surveillance and development of novel techniques that may deter larval growth, development and survival in an area. Key words: Aedes mosquitoes, Dengue, Larval density, Mosquito-borne viral diseases, Siliguri

Awareness and Practice on Prevention and Control of Dengue among Community People of Lalitpur Metropolitan City

Background: Dengue is a mosquito-borne viral disease that has rapidly spread in many countries worldwide in recent years. Dengue is a major public health problem in many countries. Dengue is a rapidly emerging disease in Nepal that is endemic across most provinces. The incidence of dengue has increased in recent years due to the expansion of the Aedes aegypti vector. The increasing outbreak of dengue in Nepal is becoming a major concern for the public health. Objective: The objective of the study was to assess awareness level and practice on prevention and control of dengue among community people in Lalitpur metropolitan city. Method: A community-based cross-sectional study was conducted from January to June 2023 at ten different wards in Lalitpur metropolitan city. Sample populations of 368 residents of Lalitpur metropolitan city above the age of 18 years were selected for the study. Simple random probability sampling technique used for the sample selection. Statistical Package for the Social Sciences (SPSS) 16 version used to analyze the data. Result: Majority (98.1%) of respondents knew about dengue fever. Most of the respondents (47.1%) answered that dengue is caused by aedes mosquito. Majority (71.4%) of respondents stated that dirty water was breeding sites of dengue mosquito. Primary preventive measures used were cleanliness 34.1 percent followed by use of mosquito net/coil 31.4 percent. The community people had good awareness (79.3%) of dengue, but poor practice (56.79%) in prevention and control of dengue. According to this study, socio-demographic factors such as age, sex, and education level were significantly linked to the knowledge level of the participants. Conclusion: According to this study, the community people had a good awareness level of dengue (79.3%). However, their practice of prevention and control of dengue was found to be poor (56.79%).

A serotype-specific and tiled amplicon multiplex PCR method for whole genome sequencing of dengue virus

Dengue fever, a mosquito-borne viral disease of significant public health concern in tropical and subtropical regions, is caused by any of the four serotypes of the dengue virus (DENV1–4). Cutting-edge technologies like next-generation sequencing (NGS) are revolutionizing virology, enabling in-depth exploration of DENV's genetic diversity. Here, we present an optimized workflow for full-genome sequencing of DENV 1–4 utilizing tiled amplicon multiplex PCR and Illumina sequencing. Our assay, sequenced on the Illumina MiSeq platform, demonstrates its ability to recover the full-length dengue genome across various viral abundances in clinical specimens with high-quality base coverage. This high quality underscores its suitability for precise examination of intra-host diversity, enriching our understanding of viral evolution and holding potential for improved diagnostic and intervention strategies in regions facing dengue outbreaks.

Travel surveillance uncovers dengue virus dynamics and introductions in the Caribbean

Dengue is the most prevalent mosquito-borne viral disease in humans, and cases are continuing to rise globally. In particular, islands in the Caribbean have experienced more frequent outbreaks, and all four dengue virus (DENV) serotypes have been reported in the region, leading to hyperendemicity and increased rates of severe disease. However, there is significant variability regarding virus surveillance and reporting between islands, making it difficult to obtain an accurate understanding of the epidemiological patterns in the Caribbean. To investigate this, we used travel surveillance and genomic epidemiology to reconstruct outbreak dynamics, DENV serotype turnover, and patterns of spread within the region from 2009-2022. We uncovered two recent DENV-3 introductions from Asia, one of which resulted in a large outbreak in Cuba, which was previously under-reported. We also show that while outbreaks can be synchronized between islands, they are often caused by different serotypes. Our study highlights the importance of surveillance of infected travelers to provide a snapshot of local introductions and transmission in areas with limited local surveillance and suggests that the recent DENV-3 introductions may pose a major public health threat in the region.

Medicinal Plants Used in Sri Lankan Traditional Medicine for Dengue Fever

Dengue fever, a mosquito-borne viral infectious disease caused by the dengue virus, is a significant global health concern, especially in tropical and subtropical regions. Despite preventive efforts, Sri Lanka faces recurring dengue outbreaks, with the Western province being the most affected. Current treatments primarily focus on supportive care, as specific antiviral therapies remain elusive. This review presents an overview of dengue, its clinical presentations, the dengue burden in Sri Lanka, and the potential of Sri Lankan medicinal plants used in traditional medicine for treating dengue. Several plants, such as Munronia pinnata, Azardirachta indica, Cissampelos pareira L., Carica papaya, Zingiber officinale, Curcuma longa, and Bambusa vulgaris, show antiviral properties against dengue. The utilization of these medicinal plants in dengue treatment could offer a promising avenue for further research and drug development.