Identifying villages and breeding habitats for dengue transmission in Thailand: insights from long-term larval surveys.

BACKGROUND: In Thailand, the Department of Disease Control (DDC) regularly performs visual larval surveys throughout the country to monitor dengue fever outbreaks. Since 2016, the DDC switched from a paper-based to a digital-based larval survey process. The significant amount of larval survey data collected digitally presents a valuable opportunity to precisely identify the villages and breeding habitats that are vulnerable to dengue transmission. METHODS: The study used digitally collected larval survey data from 2017 to 2019. It employed larval indices to evaluate the risk of dengue transmission in villages based on seasonal, regional, and categorical perspectives. Furthermore, the study comprehensively scrutinized each container category by employing different measures to determine its breeding preference ratio. RESULTS: The result showed that villages with a very high-risk of dengue transmission were present year-round in all regions, with the highest proportion during the rainy season. The Southern region had more high-risk villages during the winter season due to rainfall. Slums and residential communities were more vulnerable to dengue than commercial areas. All container categories could potentially serve as breeding habitats for dengue-carrying mosquitoes, with abandoned containers being the most significant breeding sites. CONCLUSIONS: The risk of dengue transmission was present year-round throughout Thailand. This underscores the importance of community and government initiatives, along with sustained public awareness campaigns and active community engagement, to efficiently and permanently eradicate mosquito breeding habitats. It should be noted that larval indices may not strongly correlate with dengue cases, as indicated by the preliminary analysis. However, they offer valuable insights into potential breeding sites for targeted preventive measures.

Exploring community needs in combating aedes mosquitoes and dengue fever: a study with urban community in the recurrent hotspot area.

BACKGROUND: Aedes mosquitoes are the main vector of dengue infection, a global health threat affecting millions of people annually. Conventional prevention and control methods against dengue outbreaks have only achieved marginal success. Recognizing the complex issue at hand, a multilevel participatory approach is crucial. Thus, alternative strategies that involve community engagement are increasingly being considered and attempted. While community-based vector control programs have been conducted, sustaining behavioral changes among the population remains a challenge. This study aimed to identify the specific community needs in combating Aedes mosquitoes and dengue fever as a basis to guide the development of community-driven initiatives and foster a deeper sense of ownership in the fight against dengue. METHODS: Between 1 August 2022 and 30 November 2022, we conducted a study in Hulu Langat district, Selangor, using a mixed-method design. All participants consented to the study, which comprised 27 participants (FGDs) and 15 participants (IDIs). The IDIs included two participants with a history of dengue fever, one community leader, one faith leader, seven local authorities, and four district health officers. Semi-structured interviews and discussions were performed among stakeholders and community members recruited via purposive and snowball sampling techniques. All interviews were audio-recorded before being analyzed using reflexive thematic analysis. RESULTS: These results derived from qualitative data explored the perspectives and needs of communities in combating Aedes mosquitoes and dengue fever. Interviews were conducted with various stakeholders, including community members, leaders, and health officers. The study identified the necessity of decisive actions by authorities to address the impact of the dengue epidemic, the importance of community engagement through partnerships and participatory approaches, the potential benefits of incentives and rewards to enhance community participation, and the need for sustained community engagement and education, especially via the involvement of young people in prevention efforts. These findings provide valuable insights into the design of effective strategies against Aedes mosquitoes and dengue fever. CONCLUSIONS: In short, there is an urgent need for a comprehensive approach involving multiple stakeholders in the fight against Aedes mosquitoes and dengue fever. The approach should incorporate efforts to raise awareness, provide practical resources, and foster community responsibility. The active involvement of teenagers as volunteers can contribute to long-term prevention efforts. Collaboration, resource allocation, and community engagement are crucial for effective dengue control and a healthier environment.

Factors influencing the community participation approaches used in Aedes mosquito management in the Torres Strait, Australia.

BACKGROUND: Aedes-borne disease risk is increasing in tropical and sub-tropical regions across the globe. While Aedes-borne disease continues to disproportionally affect low- and middle-income countries, parts of high-income countries, such as the Torres Strait region in Australia are also at risk. The Torres Strait is a group of islands located between Cape York Peninsula in far north Queensland, Australia and Papua New Guinea. The Torres Strait has both Aedes albopictus and Aedes aegypti and is close to Papua New Guinea where dengue fever is endemic. Managing Aedes-borne disease risk requires a range of strategies, including community participation. Existing research shows that high-income countries tend to favour government-led (top-down) informing approaches when engaging communities in Aedes mosquito management. Little is known about the factors that influence the choice of community participation approaches in Aedes mosquito management particularly in a high-income country setting, such as Australia. This research contributes to filling this knowledge gap by exploring the community participation approaches used in Aedes mosquito management and the factors influencing these choices in the Torres Strait. METHODS: 16 semi-structured interviews were conducted with local government and state government agencies working in Aedes mosquito management in the Torres Strait. Six key mosquito management plans and policies were also reviewed. Thematic analysis was used to identify, analyse and attribute meaning from the data collected. RESULTS: A range of community participation approaches were used within the two main Aedes mosquito management programs (Aedes albopictus Elimination Program and the Torres Strait Island Regional Council, Environmental Health Program) in the Torres Strait. These approaches included door-to-door inspections, awareness raising strategies, and community clean-up events. Approaches were chosen for reasons related to regulations, attitude and beliefs, and resourcing. CONCLUSIONS: This study revealed the use of both top-down and bottom-up approaches to engaging the community in Aedes mosquito management in the Torres Strait. These findings contribute to a better understanding of why bottom-up approaches are used, which is valuable for shaping future policy decisions. This study also provides suggestions on ways to enhance community participation in the Torres Strait, which could also be considered in other similar tropical regions.

Dengue risk zone mapping of Thiruvananthapuram district, India: a comparison of the AHP and F-AHP methods.

Dengue fever, which is spread by Aedes mosquitoes, has claimed many lives in Kerala, with the Thiruvananthapuram district bearing the brunt of the toll. This study aims to demarcate the dengue risk zones in Thiruvananthapuram district using the analytical hierarchy process (AHP) and the fuzzy-AHP (F-AHP) methods. For the risk modelling, geo-environmental factors (normalized difference vegetation index, land surface temperature, topographic wetness index, land use/land cover types, elevation, normalized difference built-up index) and demographic factors (household density, population density) have been utilized. The ArcGIS 10.8 and ERDAS Imagine 8.4 software tools have been used to derive the risk zone maps. The area of the risk maps is classified into five zones. The dengue risk zone maps were validated using dengue case data collected from the Integrated Disease Surveillance Programme portal. From the receiver operating characteristic (ROC) curve analysis and the area under the ROC curve (AUC) values, it is proved that the F-AHP method (AUC value of 0.971) has comparatively more prediction capability than the AHP method (AUC value of 0.954) in demarcating the dengue risk zones. Also, based on the comparison of the risk zone map with actual case data, it was confirmed that around 82.87% of the dengue cases occurred in the very high and high-risk zones, thus proving the efficacy of the model. According to the dengue risk map prepared using the F-AHP model, 9.09% of the area of Thiruvananthapuram district is categorized as very high risk. The prepared dengue risk maps will be helpful for decision-makers, staff with the health, and disaster management departments in adopting effective measures to prevent the risks of dengue spread and thereby minimize loss of life.

Impact of environmental factors on the spread of dengue fever in Sri Lanka.

Dengue fever is a mosquito-borne viral disease caused by the dengue virus of the Flaviviridae family and is responsible for colossal health and economic burden worldwide. This study aimed to investigate the effect of environmental, seasonal, and spatial variations on the spread of dengue fever in Sri Lanka. The study used secondary data of monthly dengue infection and the monthly average of environmental parameters of 26 Sri Lankan regions from January 2015 to December 2019. Besides the descriptive measurements, Kendall's tau_b, Spearman's rho, and Kruskal-Wallis H test have been performed as bivariate analyses. The multivariate generalized linear negative binomial regression model was applied to determine the impacts of meteorological factors on dengue transmission. The aggregate negative binomial regression model disclosed that precipitation (odds ratio: 0.97, p < 0.05), humidity (odds ratio: 1.05, p < 0.01), and air pressure (odds ratio: 1.46, p < 0.01) were significantly influenced the spread of dengue fever in Sri Lanka. The bioclimatic zone is the vital factor that substantially affects the dengue infection, and the wet zone (odds ratio: 6.41, p < 0.05) was more at-risk than the dry zone. The climate season significantly influenced dengue fever transmission, and a higher infection rate was found (odds ratio: 1.46, p < 0.01) in the northeast monsoon season. The findings of this study facilitate policymakers to improve the existing dengue control strategies focusing on the meteorological condition in the local as well as global perspectives.

Determinants of stakeholders' attitudes and intentions toward supporting the use of Wolbachia-infected Aedes mosquitoes for dengue control.

BACKGROUND: A recent approach in controlling dengue is by using the Wolbachia-infected Aedes mosquito (WiAM). The approach has been reported to be more effective than traditional methods, such as fogging. Therefore, it is imperative to assess the factors predicting its acceptance among stakeholders before implementing this technology more widely in Malaysia. METHODS: The survey data were collected from two primary stakeholder groups using a stratified random sampling technique. The two primary stakeholder groups were scientists (n = 202) and the public (n = 197) in the Klang Valley region of Malaysia, a hot spot area known for the high rate of dengue cases. The respondents answered questions on a seven-point Likert scale survey regarding trust in key players, attitudes toward nature versus materialism, religiosity, perceived benefits, perceived risks, attitudes, and intentions. The data were analyzed using Smart Partial Least Square (SmartPLS) software (version 3.2.6) to determine the predictors influencing attitudes and intentions to support the use of WiAM technology. RESULTS: The results indicated a strong positive relationship between attitudes and intentions to support the use of WiAM (ß = 0.676, p < 0.001). The most important significant predictor for attitudes was perceived benefits (ß = 0.493, p < 0.001), followed by perceived risks (ß = - 0.080, p = 0.048). Trust in key players, attitudes toward nature versus material, and religiosity had indirect relationships with attitudes through the perceived benefits and risks. CONCLUSIONS: The identified predictors can serve as indicators for the decision-making process regarding WiAM implementation in Malaysia and other developing countries with similar demographics and cultures.

Community participation and empowerment approaches to Aedes mosquito management in high-income countries: a scoping review.

High-income countries (HICs) in sub-tropical and tropical regions are at an increasing risk of Aedes mosquito-borne disease (MBD) outbreaks such as dengue fever. As the Aedes mosquito predominately lives and breeds in and around people's homes, community participation in MBD management is an important part of preventing MBD outbreaks. Historically, government-led strategies have dominated community participation efforts as opposed to strategies co-designed or led by the community. A scoping review was conducted to describe the community participation and empowering approaches used in Aedes mosquito management specifically in HICs, and to identify any reported outcomes of these methods. A systematic search of peer-reviewed literature using electronic databases Medline (OVID), Web of Science, Scopus and ProQuest-Science and Technology as well as grey literature, found 19 studies that matched the review criteria. The review findings highlight a lack of empirical evidence to inform participatory and empowering approaches to mosquito management in HICs. Moreover, the rationale for using predominantly government-led approaches is not clear. Further research is required to better understand best approaches and barriers to employing empowering approaches in mosquito management in HICs.

Microencapsulation Preservation of the Stability and Efficacy of Citrus Grandis Oil-Based Repellent Formulation against Aedes aegypti during Storage.

Essential oils have been widely used as an active ingredient in mosquito repellent products. However, essential oils are highly unstable and prone to degradation when exposed to the environment during storage. Microencapsulation techniques help to maintain the stability of molecules in essential oils that are sensitive to environmental stress, and therefore improve shelf life. In this study, the physical stability and efficacy of a repellent formulation consisting of encapsulated Citrus grandis essential oil (CGEO) were evaluated under different storage conditions over a 12-month period by comparing the formulation with a non-encapsulated formulation. The formulations were both stored under two different storage conditions, i.e., 25 ± 2 °C/60% ± 5% relative humidity (RH) and 40 ± 2 °C/75% RH ± 5%, for 12 months. Droplet size, zeta potential, and pH value were measured after 1, 6, and 12 months of storage to determine their stability. For the study of efficacy, each formulation was tested against Aedes aegypti under laboratory conditions. We found that the microencapsulated formulation's physical characteristics showed insignificant changes as compared with the non-encapsulated formulation during storage. The microencapsulated formulation demonstrated better repellent effects, sustaining high protection (>80%) for 4 more hours of exposure after 12 months of storage as compared with the non-encapsulated formulation that demonstrated high protection for only an hour post application. Microencapsulation helped to preserve the stability of the formulation, which resulted in high protection being maintained for over 12 months of storage.

Basic Reproduction Number of Chikungunya Virus Transmitted by Aedes Mosquitoes.

We estimated the weighted mean basic reproduction number (R0) of chikungunya virus based on outbreak size. R0 was 3.4 (95% CI 2.4-4.2) and varied for 2 primary chikungunya mosquito vectors: 4.1 (95% CI 1.5-6.6) for Aedes aegypti and 2.8 (95% CI 1.8-3.8) for Ae. albopictus.

Diterpenes and their derivatives as promising agents against dengue virus and dengue vectors: A literature-based review.

Dengue, a mosquito-borne viral disease, causes about 100 million cases of infection annually. It is a major public concern, and if left untreated or improperly diagnosed, may cause serious health problems or even death. Historically, dengue has not considered priorities for pharmaceutical companies made the available treatment options. Therefore, medicinal scientists are revealing new insights and enabling novel interventions and approaches to dengue prevention and control. Diterpenes, a class of terpenes have gained much attention due to their diverse biological effects. This review aimed at summarizing available evidences of diterpenes and their derivatives acting against dengue virus and their vectors. For this, an updated search was made in the databases: PubMed and ScienceDirect by using specific keywords. Among the 117 published reports, a total of 30 articles was included in this review. Findings suggest that a number of diterpenes and/or their derivatives act against dengue virus and their two potential vectors namely Aedes aegypti and Ae. albopictus. In conclusion, diterpenes and their derivatives may have the potential alternative therapeutic tools for the management of dengue virus and some associated diseases transmitted by Aedes mosquito.

Zika virus outbreak: a review of neurological complications, diagnosis, and treatment options.

Zika virus (ZIKV) is an arbovirus transmitted mainly by mosquitos of Aedes species. The virus has emerged in recent years and spread throughout North and South Americas. The recent outbreak of ZIKV started in Brazil (2015) has resulted in infections surpassing a million mark. Contrary to the previous beliefs that Zika causes mildly symptomatic infections fever, headache, rash, arthralgia, and conjunctivitis, the recent outbreak associated ZIKV to serious neurological complications such as microcephaly, Guillain-Barré syndrome, and eye infections. The recent outbreak has resulted in an astonishing number of microcephaly cases in fetus and infants. Consequently, numerous studies were conducted using in vitro cell and in vivo animal models. These studies showed clear links between ZIKV infections and neurological abnormalities. Diagnosis methods based on nucleic acid and serological detection facilitated rapid and accurate identification of ZIKV infections. New transmission modalities such as sexual and transplacental transmission were uncovered. Given the seriousness of ZIKV infections, WHO declared the development of safe and effective vaccines and new antiviral drugs as an urgent global health priority. Rapid work in this direction has led to the identification of several vaccine and antiviral drug candidates. Here, we review the remarkable progress made in understanding the molecular links between ZIKV infections and neurological irregularities, new diagnosis methods, potential targets for antiviral drugs, and the current state of vaccine development.

Risk of Zika virus transmission in the Euro-Mediterranean area and the added value of building preparedness to arboviral threats from a One Health perspective.

In the alarming context of risk of Zika virus (ZIKV) transmission in the Euro-Mediterranean area, there is a need to examine whether capacities to detect, diagnose and notify ZIKV infections in the region are in place and whether ongoing capacity-building initiatives are filling existing gaps.The MediLabSecure network, created in 2014, comprises 55 laboratories of virology and medical entomology and 19 public health institutions in 19 countries in the Balkans, North-Africa, the Middle-East and the Black Sea regions. It aims to set up awareness, risk assessment, monitoring and control of emerging and re-emerging vector-borne viruses. We here examine the actions and strategies that MediLabSecure has been implementing and how they will contribute to the prevention and control of the ZIKV threat in the Euro-Mediterranean area.Capacity-building for arbovirus diagnostics is a major objective of the project and follows a methodological rather than disease-driven approach. This enables the implementation of laboratory trainings on techniques that are common to several arboviruses, including ZIKV, and putting into action appropriate diagnostic tools in the target region.Moreover, by its One Health approach and the interaction of its four sub-networks in human virology, animal virology, medical entomology and public health, MediLabSecure is fostering intersectoral collaboration, expertise and sharing of information. The resulting exchanges (methodological, communication and operational) across disciplines and across countries, dedicated research on intersectoral collaboration and increasing diagnostic capacities are providing new paths and tools to public health professionals to face emerging viral threats such as a ZIKV epidemic in the Euro-Mediterranean region.

Presence of Arboviral Vector in Tourist Attractions and Public Places: Abundance, Associated Factors and Susceptibility to Temephos.

<b>Background and Objective:</b> <i>Aedes</i> mosquito is a competent vector of arboviruses, mainly dengue, chikungunya, Zika and yellow fever. The high incidence of arboviral infections among travelers indicated the vulnerability of tourist attractions and public places visitors to arboviral infections. This study aimed to determine the presence and population density of <i>Aedes</i> mosquitoes at the places, as well as the susceptibility to temephos larvicide. <b>Materials and Methods:</b> A total of 17 tourist attractions and public places in four districts/cities of Central Java Province were selected as study sites and 25-40 ovitraps were installed in each location for three days. The coordinates, altitude, vegetation density, shade, wind speed, air temperature and humidity were recorded. Ovistrips and water of each ovitrap were observed in the laboratory to determine the ovitrap index (OI) and egg density index (EDI), mosquito species and their susceptibility to temephos. <b>Results:</b> A total of 12,231 eggs were obtained with a range, OI and EDI of 0-1,024, 42% and 31.93 eggs/trap, respectively. Vegetation density, shade and wind speed were significantly associated with the presence of <i>Aedes </i>eggs in the ovitraps (p<0.05), while altitude, temperature and air humidity were correlated with the average of <i>Aedes</i> eggs per ovitrap. <b>Conclusion:</b> Although <i>Aedes</i> larvae in all study sites were susceptible to temephos 0.02 mg/L the results indicated the vulnerability of visitors to <i>Aedes</i>-borne diseases. Further investigation of arbovirus infections in <i>Aedes</i> mosquitoes at tourist attractions and public places is necessary conducted to evaluate the potential and risk of pathogen transmission to visitors.

In-vitro assessment of cutaneous immune responses to aedes mosquito salivary gland extract and dengue virus in Cambodian individuals.

Dengue virus (DENV) poses a global health threat, affecting millions individuals annually with no specific therapy and limited vaccines. Mosquitoes, mainly Aedes aegypti and Aedes albopictus worldwide, transmit DENV through their saliva during blood meals. In this study, we aimed to understand how Aedes mosquito saliva modulate skin immune responses during DENV infection in individuals living in mosquito-endemic regions. To accomplish this, we dissociated skin cells from Cambodian volunteers and incubated them with salivary gland extract (SGE) from three different mosquito strains: Ae. aegypti USDA strain, Ae. aegypti and Ae. albopictus wild type (WT) in the presence/absence of DENV. We observed notable alterations in skin immune cell phenotypes subsequent to exposure to Aedes salivary gland extract (SGE). Specifically, exposure lead to an increase in the frequency of macrophages expressing chemokine receptor CCR2, and neutrophils expressing CD69. Additionally, we noted a substantial increase in the percentage of macrophages that became infected with DENV in the presence of Aedes SGE. Differences in cellular responses were observed when Aedes SGE of three distinct mosquito strains were compared. Our findings deepen the understanding of mosquito saliva's role in DENV infection and skin immune responses in individuals regularly exposed to mosquito bites. This study provides insights into skin immune cell dynamics that could guide strategies to mitigate DENV transmission and other arbovirus diseases.

Immunization against dengue virus infection is coercive: A timely call.

Background: In context, the dengue virus causes dengue fever, which is spread by mosquito bites. About 22,000 people every year lose their lives as a direct result of it. Dengue fever has been on the rise recently, and its spread has alarmed health officials throughout the world. Discussion: Vaccination is essential for the prevention and management of dengue cases because there is currently no particular cure against dengue virus. The current dengue epidemic calls for urgent action in the form of immunization. However, there are serious drawbacks to using existing vaccines like Dengvaxia. Besides, the Qdenga vaccine has not yet been approved by the FDA in the United States. On the other hand, positive results from a phase II randomized and controlled clinical study of the TV005 tetravalent live-attenuated dengue vaccine were recently reported in Bangladesh. Only an effective vaccination can drastically lower dengue infection and mortality rates. Conclusion: The development of safe and effective vaccination, as well as their correct dissemination, is an essential requirement for the people of Bangladesh and the rest of the globe, and we concentrated on this critical problem in this article.

Validation of CRISPR activation system in Aedes cells using multicistronic plasmid vectors.

Aedes mosquitoes transmit several pathogens including flaviviruses to humans which result in high morbidity and mortality. Owing to adaptability and climate change, these mosquito vectors are predicted to establish in new geographical areas thus exposing larger populations to the risk of infection. Therefore, control of Aedes vector is necessary to prevent disease transmission. Recently, genetic approaches to vector control have shown promise; however, the tools and methods for manipulating the mosquito genome are rather limited. While CRISPR-Cas9 system has been adapted for gene editing purposes in Aedes mosquito, the dCas9-based transcription control of genes remain unexplored. In this study we report implementation of the CRISPR activation system in Aedes cells. For this we designed, constructed and tested a bi-partite plasmid-based strategy that allows expression of the dCas9-VPR and targeting guide RNA together with a reporter cassette. Quantitative analysis of the fluorescent reporter gene levels showed a robust over-expression validating CRISPR activation in Aedes cells. This strategy and the biological parts will be useful resource for synthetic transcription factor-based robust upregulation of Aedes genes for application of synthetic biology approaches for vector control.

Molecular surveillance of dengue virus in field-collected Aedes mosquitoes from Bhopal, central India: evidence of circulation of a new lineage of serotype 2.

Introduction: Dengue fever is hyperendemic in several Southeast and South Asian countries, including India, with all four serotypes (DENV 1-4) circulating at different periods and in different locations. Sustainable and improved virological and entomological surveillance is the only tool to prevent dengue and other vector-borne diseases. Objectives: The present study has been carried out to detect and characterize the circulating dengue virus (DENV) in field-collected Aedes mosquitoes in Bhopal, Central India. Methods: Aedes mosquitoes were collected from 29 localities within Bhopal city during October 2020 to September 2022. DENV infection was assessed in the individual head and thorax regions of Aedes mosquitoes using reverse transcriptase PCR. Positive samples were sequenced, and the circulating serotypes and genotypes were determined using phylogenetic analysis. Results: DENV RNA was detected in 7 Aedes aegypti and 1 Aedes albopictus, with infection rates of 0.59 and 0.14%, respectively. Phylogenetic analysis revealed all the isolates belonged to DENV serotype 2 and distinctly clustered with the non-Indian lineage (cosmopolitan genotype 4a), which was not recorded from the study area earlier. The time to most common recent ancestor (TMRCA) of these sequences was 7.4 years old, with the highest posterior density (HPD) of 3.5-12.2 years, indicating that this new lineage emerged during the year 2014. This is the first report on the DENV incrimination in both Ae. aegypti and Ae. albopictus mosquitoes collected from Bhopal, Central India. Conclusion: The observed emergence of the non-Indian lineage of DENV-2 in Bhopal, which again is a first report from the area, coincides with the gradual increase in DENV cases in Bhopal since 2014. This study emphasizes the importance of DENV surveillance and risk assessment in this strategically important part of the country to decipher its outbreak and severe disease-causing potential.

Analysis of dengue fever disease in West Africa.

Dengue fever disease (DFD) which is caused by four antigenically distinct dengue viruses (DENV) presents a global health threat, with tropical and subtropical regions at a greater risk. The paucity of epidemiological data on dengue in West African subregion endangers efforts geared toward disease control and prevention. A systematic search of DFD prevalence, incidence, and DENV-infected Aedes in West Africa was conducted in PubMed, Scopus, African Index Medicus, and Google Scholar in line with the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines. A total of 58 human prevalence studies involving 35,748 people from 8 countries were identified. Two incidence and six DENV-infected studies were also reviewed. Nigeria and Burkina Faso contributed the majority of the prevalence studies which spanned between 1968 and 2018, with a considerable variation in coverage among the countries reviewed in this study. An average prevalence of 20.97% was observed across both general prevalence and acute DENV infection study categories, ranging between 0.02% and 93%. The majority of these studies were conducted in acute febrile patients with a prevalence range of 0.02-93% while 19% (n = 11) of all studies were general population-based studies and reported a prevalence range of 17.2-75.8%. DENV-infected Aedes aegypti were reported in four out of the five countries with published reports; with DENV-2 found circulating in Cape Verde, Senegal, and Burkina Faso while DENV-3 and DENV-4 were also reported in Senegal and Cape Verde, respectively. High prevalence of DFD in human populations and the occurrence of DENV-infected A. aegypti have been reported in West Africa, even though weaknesses in study design were identified. Epidemiological data from most countries and population in the subregion were scarce or non-existent. This study highlights the epidemic risk of DFD in West Africa, and the need for research and surveillance to be prioritized to fill the data gap required to enact effective control measures.

Preparedness for the Dengue Epidemic: Vaccine as a Viable Approach.

Dengue fever is one of the significant fatal mosquito-borne viral diseases and is considered to be a worldwide problem. Aedes mosquito is responsible for transmitting various serotypes of dengue viruses to humans. Dengue incidence has developed prominently throughout the world in the last ten years. The exact number of dengue cases is underestimated, whereas plenty of cases are misdiagnosed as alternative febrile sicknesses. There is an estimation that about 390 million dengue cases occur annually. Dengue fever encompasses a wide range of clinical presentations, usually with undefinable clinical progression and outcome. The diagnosis of dengue depends on serology tests, molecular diagnostic methods, and antigen detection tests. The therapeutic approach relies completely on supplemental drugs, which is far from the real approach. Vaccines for dengue disease are in various stages of development. The commercial formulation Dengvaxia (CYD-TDV) is accessible and developed by Sanofi Pasteur. The vaccine candidate Dengvaxia was inefficient in liberating a stabilized immune reaction toward different serotypes (1-4) of dengue fever. Numerous promising vaccine candidates are now being developed in preclinical and clinical stages even though different serotypes of DENV exist that worsen the situation for a vaccine to be equally effective for all serotypes. Thus, the development of an efficient dengue fever vaccine candidate requires time. Effective dengue fever management can be a multidisciplinary challenge, involving international cooperation from diverse perspectives and expertise to resolve this global concern.

A case-control study to determine the risk factors of dengue fever in Chattogram, Bangladesh.

Objectives: In a tropical country like Bangladesh, where the climatic condition favors the growth of Aedes mosquito vectors, the success of dengue prevention depends largely on the proper identification and control of risk factors. Therefore this study was aimed to explore the potential risk factors and their association with dengue infection. Study design: A case-control study including 150 cases and 150 controls was conducted in Chattogram district of Bangladesh. Cases were confirmed dengue patients admitted in Chattogram medical college hospital and Bangladesh institute of tropical and infectious diseases during August and September 2019. On the other hand, controls were non-dengue patients admitted in other departments of the same hospitals through gender, age, and location matching. Methods: The questionnaire data were collected through telephone-based interviews, which included general demography, daily life activities, housing and surrounding environment of participants. Chi-square and binary logistic regression were performed to identify potential risk factors. Results: The study found that travel history to the high incidence area, staying most of the daytime in office (AOR = 18.10), living in 21-40 years old houses (AOR = 9.74), and the temporary residency in the city (AOR = 10.20) were statistically significant risk factors for getting dengue infection. However, day time sleep, house type and structure, number of family members, morning and evening walk, plant in resident, and junk yard around 250 m of the house were also showed a significant effect in chi square test. Conclusions: Results strengthen our understanding regarding the role of factors associated with daily lifestyle and living environment of people in the development of dengue and hence support the dengue control program in Bangladesh. The study will provide a basis for future extended research covering different parts of the country.