Epidemiological factors associated with dengue shock syndrome and mortality in hospitalized dengue patients in Ho Chi Minh City, Vietnam

Field deployment of Wolbachia-infected Aedes aegypti using uncrewed aerial vehicle

Over the past 50 years, there has been a marked increase in diseases like dengue fever, chikungunya, and Zika. The World Mosquito Program (WMP) has developed an approach that, instead of attempting to eliminate vector species, introduces Wolbachia into native Aedes aegypti populations through the release of Wolbachia-infected mosquitoes. Using this approach, a randomized controlled study recently demonstrated a 77% reduction in dengue across a treatment area within Yogyakarta, Indonesia. Existing release methods use the ground-based release of mosquito eggs or adults that are labor-intensive, are logistically challenging to scale up, and can be restrictive in areas where staff safety is a concern. To overcome these limitations, we developed a fully automated mosquito dosing release system that released smaller cohorts of mosquitoes over a wide area and integrated it into an uncrewed aerial vehicle. We established the effectiveness of this system using an aerial mark, release, and recapture approach. We then demonstrated that using only the aerial release method, we can establish Wolbachia infection in a naive Ae. aegypti population. In both cases, the use of aerial releases demonstrated comparable outcomes to ground-based releases without the required labor or risk. These two trials demonstrated the feasibility of using an aerial release approach for large-scale mosquito releases.

Understanding maternal sepsis risk factors and bacterial etiology: A case control study protocol

INTRODUCTION

Maternal disorders are the third leading cause of sepsis globally, accounting for 5.7 million (12%) cases in 2017. There are increasing concerns about the emergence of antimicrobial resistance (AMR) in bacteria commonly causing maternal sepsis. Our aim is to describe the protocol for a clinical and microbiology laboratory study to understand risk factors for and the bacterial etiology of maternal sepsis in a tertiary Obstetrics and Gynaecology Hospital.

METHODS

This case-control study aims to recruit 100 cases and 200 controls at Tu Du Hospital in Ho Chi Minh City, Vietnam, which had approximately 55,000 births in 2022. Women aged ≥ 18 years and ≥ 28 weeks gestation having a singleton birth will be eligible for inclusion as cases or controls, unless they have an uncomplicated localised or chronic infection, or an infection with SARS-CoV-2. Cases will include pregnant or recently pregnant women with sepsis recognised between the onset of labour and/or time of delivery/cessation of pregnancy for up to 42 days post-partum. Sepsis will be defined as suspected or confirmed infection with an obstetrically modified Sequential Organ Failure Assessment score of ≥ 2, treatment with intravenous antimicrobials and requested cultures of any bodily fluid. Controls will be matched by age, location, parity, mode of delivery and gestational age. Primary and secondary outcomes are risk factors associated with the development of maternal sepsis, the frequency of adverse outcomes due to maternal sepsis, bacterial etiology and AMR profiles of cases and controls.

DISCUSSION

This study will improve understanding of the epidemiology and clinical implications of maternal sepsis management including the presence of AMR in women giving birth in Vietnam. It will help us to determine whether women in this setting are receiving optimal care and to identify opportunities for improvement.

Assessing the impact of emergency measures in varied population density areas during a large dengue outbreak

Background

The patterns of dengue are affected by many factors, including population density and climate factors. Densely populated areas could play a role in dengue transmission due to increased human-mosquito contacts, the presence of more diverse and suitable vector habitats and breeding sites, and changes in land use. In addition to population densities, climatic factors such as temperature, relative humidity, and precipitation have been demonstrated to predict dengue patterns. To control dengue, emergency measures should focus on vector management. Most approaches to assessing emergency responses to dengue risks involve applying simulation models or describing emergency activities and the results of implementing those responses. Research using real-world data with analytical methods to evaluate emergency responses to dengue has been limited. This study investigated emergency control measures associated with dengue risks in areas with high and low population densities, considering their different control capacities.

Methodology

Data from the 2015 dengue outbreak in Kaohsiung City, Taiwan, were utilized. The government database provided information on confirmed dengue cases, emergency control measures, and climatic data. The study employed a distributed lag non-linear model (DLNM) to assess the effect of emergency control measures and their time lags on dengue risk.

Principal findings

The findings revealed that in areas with high population density, the absence of emergency measures significantly elevated the risks of dengue. However, implementing emergency measures, especially a higher number, was associated with lower risks. In contrast, in areas with low population density, the risks of dengue were only significantly elevated at the 1st week lag if no emergency control measures were implemented. When emergency activities were carried out, the risks of dengue significantly decreased only for the 1st week lag.

Conclusions

Our findings reveal distinct exposure-lag-response patterns in the associations between emergency control measures and dengue in areas with high and low population density. In regions with a high population density, implementing emergency activities during a significant dengue outbreak is crucial for reducing the risk. Conversely, in areas of low population density, the necessity of applying emergency activities may be less pronounced. The implications of this study on dengue management could provide valuable insights for health authorities dealing with limited resources.

Risk factors associated with severe dengue in Latin America: A systematic review and meta-analysis

OBJECTIVE

Severe dengue is a significant health problem in Latin America, with children being the most affected. Understanding risk factors for severe dengue is crucial for enhancing patient care. Therefore, this study aims to systematically review the literature to identify the risk factors associated with severe dengue in Latin America through systematic review and meta-analysis.

METHODS

PubMed, SciELO, LILACS and EMBASE databases were used to search for eligible scientific articles for the review. The outcomes considered were symptoms of severe dengue, hospitalisation and death. The Joanna Briggs Institute Critical Appraisal Checklist was used to assess the quality of the studies. Data analysis was performed using STATA v 13.0 software. The degree of heterogeneity between studies was quantified using the I2 measure, and statistically significant results were defined as those with p values <0.05.

RESULTS

Of the 1876 articles screened, 47 articles were included in the systematic review and 45 articles were analysed through meta-analysis. Identified risk factors associated with severe dengue included secondary dengue infection, female sex, white or Caucasian ethnicity and specific signs and symptoms such as headache, myalgia and/or arthralgia, vomiting/nausea, abdominal pain or tenderness, diarrhoea, prostration, lethargy, fatigue or similar. For the death outcome, respiratory symptoms and age <18 years were identified as risk factors. On the other hand, in women, the diagnosis of positive tourniquet test, platelet count <100,000 per μL and symptoms of capillary fragility were associated with a lower probability of death. These data highlight the importance of early screening of patients, to identify possible haemorrhagic signs and reduce deaths from dengue. This study has limitations, including possible publication bias, heterogeneity of results and study design biases.

CONCLUSION

These findings are significant for shaping strategies, management approaches and identifying high-risk groups, which will help establish future guidelines.

Age-time-specific transmission of hand-foot-and-mouth disease enterovirus serotypes in Vietnam: A catalytic model with maternal immunity

Hand, foot and mouth disease (HFMD) is highly prevalent in the Asia Pacific region, particularly in Vietnam. To develop effective interventions and efficient vaccination programs, we inferred the age-time-specific transmission patterns of HFMD serotypes enterovirus A71 (EV-A71), coxsackievirus A6 (CV-A6), coxsackievirus A10 (CV-A10), coxsackievirus A16 (CV-A16) in Ho Chi Minh City, Vietnam from a case data collected during 2013-2018 and a serological survey data collected in 2015 and 2017. We proposed a catalytic model framework with good adaptability to incorporate maternal immunity using various mathematical functions. Our results indicate the high-level transmission of CV-A6 and CV-A10 which is not obvious in the case data, due to the variation of disease severity across serotypes. Our results provide statistical evidence supporting the strong association between severe illness and CV-A6 and EV-A71 infections. The HFMD dynamic pattern presents a cyclical pattern with large outbreaks followed by a decline in subsequent years. Additionally, we identify the age group with highest risk of infection as 1-2 years and emphasise the risk of future outbreaks as over 50% of children aged 6-7 years were estimated to be susceptible to CV-A16 and EV-A71. Our study highlights the importance of multivalent vaccines and active surveillance for different serotypes, supports early vaccination prior to 1 year old, and points out the potential utility for vaccinating children older than 5 years old in Vietnam.

Severe dengue in the intensive care unit

Dengue fever is considered the most prolific vector-borne disease in the world, with its transmission rate increasing more than eight times in the last two decades. While most cases present mild to moderate symptoms, 5% of patients can develop severe disease. Although the mechanisms are yet not fully comprehended, immune-mediated activation leading to excessive cytokine expression is suggested as a cause of the two main findings in critical patients: increased vascular permeability that may shock and thrombocytopenia, and coagulopathy that can induce hemorrhage. The risk factors of severe disease include previous infection by a different serotype, specific genotypes associated with more efficient replication, certain genetic polymorphisms, and comorbidities such as diabetes, obesity, and cardiovascular disease. The World Health Organization recommends careful monitoring and prompt hospitalization of patients with warning signs or propensity for severe disease to reduce mortality. This review aims to update the diagnosis and management of patients with severe dengue in the intensive care unit.

Dengue virus serotype did not contribute to clinical severity or mortality in Taiwan's largest dengue outbreak in 2015

BACKGROUND

Dengue virus serotype 2 (DENV-2) was the major serotype in the 2015 dengue outbreak in Taiwan, while DENV-1 and DENV-3 were dominant between 2005 and 2014. We aimed to investigate whether DENV-2 contributed to disease severity and mortality in the outbreak in Kaohsiung city, Taiwan.

METHODS

We collected serum samples from dengue patients to detect the presence of DENV and determine the serotypes by using quantitative reverse transcription-polymerase chain reaction. Our cohorts comprised 105 DENV-1-infected cases and 1,550 DENV-2-infected cases. Demographic data, DENV serotype, and comorbidities were covariates for univariate and multivariate analyses to explore the association with severity and mortality.

RESULTS

The results suggested that DENV-1 persisted and circulated, while DENV-2 was dominant during the dengue outbreak that occurred between September and December 2015. However, DENV-2 did not directly contribute to either severity or mortality. Aged patients and patients with diabetes mellitus (DM) or moderate to severe chronic kidney disease (CKD) had a higher risk of developing severe dengue. The mortality of dengue patients was related to a higher Charlson comorbidity index score and severe dengue. Among DENV-2-infected patients and older patients, preexisting anti-dengue IgG, DM, and moderate to severe CKD were associated with severe dengue. Moreover, female sex and severe dengue were associated with a significantly higher risk of death.

CONCLUSIONS

Our findings highlight the importance of timely serological testing in elderly patients to identify potential secondary infections and focus on the meticulous management of elderly patients with DM or moderate to severe CKD to reduce dengue-related death.

[Association between schooling and mortality rate from dengue in Brazil]

Dengue may be associated with individual level variables, such as schooling, increasing the risk of illness. The objective of this study is to analyze the disparities in dengue mortality among the least and the most educated in Brazil, from 2010 to 2018. This is a retrospective ecological study of the differences in the mortality rate due to dengue between the less and the more educated people in Brazil, according to the mortality rates due to general dengue, by age, sex, and Federative Unit (UF). A bootstrap and multiple imputation procedure for the variable schooling was implemented to consider the multilevel structure of the data from each UF over the years. For each aggregate bank generated, a multilevel Poisson model was adjusted. The improvement in the education level of the Brazilian population did not reflect on the decrease in mortality from dengue. There was an increase in the mortality rate from dengue in Brazil and an increase in the difference in mortality rates between less and more educated. Regardless of the imputation process, the results showed higher mortality rates from dengue among the less educated. Low schooling affected younger people more pronouncedly.

Clinical and Etiological Profile of Acute Undifferentiated Fever With Thrombocytopenia in an Emergency Department

INTRODUCTION

Acute undifferentiated fever with thrombocytopenia is a common and challenging clinical presentation encountered in the emergency departments of tertiary care centers, particularly in tropical regions, often requiring prompt evaluation and management. The study aimed to explore the clinical and etiological profile of acute undifferentiated fever with thrombocytopenia in the Emergency Department of Indira Gandhi Institute of Medical Sciences, Patna. It investigates factors associated with patient outcomes and compares platelet transfusion requirements among different etiological groups.

METHODS

In this cross-sectional observational study, 350 patients with acute undifferentiated fever with thrombocytopenia were analyzed for one year from October '21 to September '22. Pre-existing chronic infectious diseases, liver cirrhosis, and autoimmune conditions were excluded.

RESULTS

Thrombocytopenia was observed in all patients, with 65% having platelet counts below 50,000/µL. Associations were found between the degree of thrombocytopenia and organ dysfunction, shock, and third space loss. Logistic regression analysis identified thrombocytopenia, organ dysfunction, and platelet transfusion requirement as significant predictors of the overall outcome. Etiological group comparisons revealed higher platelet transfusion requirements in the bacterial group.

CONCLUSION

Prompt recognition and management of thrombocytopenia in acute undifferentiated fever are vital. Thrombocytopenia, along with organ dysfunction and shock, significantly influence patient outcomes. Tailored interventions based on etiological factors are crucial. Further research should focus on specific viral aetiologies in acute undifferentiated fever with thrombocytopenia.

Direct and indirect effects of age on dengue severity: The mediating role of secondary infection

Severe dengue occurrence has been attributed to increasing age and different dengue virus (DENV) serotypes that cause secondary infections and immune-enhancing phenomena. Therefore, we examined if the effect of age on dengue severity was mediated by infectivity status while controlling for sex and region. Further, we assessed the spatial clustering of dengue severity for individuals with primary and secondary infection across Mexican municipalities. Health data from 2012 to 2017 was retrieved from Mexico's Ministry of Health. A mediation analysis was performed using multiple logistic regression models based on a directed acyclic graph. The models were explored for the direct effect of age on dengue severity and its indirect impact through secondary infection. In addition, severe dengue clusters were determined in some Northeastern and Southeastern municipalities through spatial analysis. We observed a nonlinear trend between age and severe dengue. There was a downward trend of severe dengue for individuals between 0 and 10 years and an upward trend above 10 years. The effect of age on dengue severity was no longer significant for individuals between 10 and 60 years after introducing infectivity status into the model. The mediating role of infectivity status in the causal model was 17%. Clustering of severe dengue among individuals with primary infection in the Northeastern region may point to the high prevalence of DENV-3 in the region. Public health efforts may prevent secondary infection among infants and the aged. In addition, there should be a further investigation into the effect of DENV-3 in individuals with primary disease.

The spatio-temporal distribution of acute encephalitis syndrome and its association with climate and landcover in Vietnam

BACKGROUND

Acute encephalitis syndrome (AES) differs in its spatio-temporal distribution in Vietnam with the highest incidence seen during the summer months in the northern provinces. AES has multiple aetiologies, and the cause remains unknown in many cases. While vector-borne disease such as Japanese encephalitis and dengue virus and non-vector-borne diseases such as influenza and enterovirus show evidence of seasonality, associations with climate variables and the spatio-temporal distribution in Vietnam differs between these. The aim of this study was therefore to understand the spatio-temporal distribution of, and risk factors for AES in Vietnam to help hypothesise the aetiology.

METHODS

The number of monthly cases per province for AES, meningitis and diseases including dengue fever; influenza-like-illness (ILI); hand, foot, and mouth disease (HFMD); and Streptococcus suis were obtained from the General Department for Preventive Medicine (GDPM) from 1998-2016. Covariates including climate, normalized difference vegetation index (NDVI), elevation, the number of pigs, socio-demographics, JEV vaccination coverage and the number of hospitals were also collected. Spatio-temporal multivariable mixed-effects negative binomial Bayesian models with an outcome of the number of cases of AES, a combination of the covariates and harmonic terms to determine the magnitude of seasonality were developed.

RESULTS

The national monthly incidence of AES declined by 63.3% over the study period. However, incidence increased in some provinces, particularly in the Northwest region. In northern Vietnam, the incidence peaked in the summer months in contrast to the southern provinces where incidence remained relatively constant throughout the year. The incidence of meningitis, ILI and S. suis infection; temperature, relative humidity with no lag, NDVI at a lag of one month, and the number of pigs per 100,000 population were positively associated with the number of cases of AES in all models in which these covariates were included.

CONCLUSIONS

The positive correlation of AES with temperature and humidity suggest that a number of cases may be due to vector-borne diseases, suggesting a need to focus on vaccination campaigns. However, further surveillance and research are recommended to investigate other possible aetiologies such as S. suis or Orientia tsutsugamushi.

Development and Utility of Practical Indicators of Critical Outcomes in Dengue Patients Presenting to Hospital: A Retrospective Cross-Sectional Study

Global travel and climate change have drastically increased the number of countries with endemic or epidemic dengue. The largest dengue outbreak in Taiwan, with 43,419 cases and 228 deaths, occurred in 2015. Practical and cost-effective tools for early prediction of clinical outcomes in dengue patients, especially the elderly, are limited. This study identified the clinical profile and prognostic indicators of critical outcomes in dengue patients on the basis of clinical parameters and comorbidities. A retrospective cross-sectional study was conducted in a tertiary hospital from 1 July 2015 to 30 November 2015. Patients diagnosed with dengue were enrolled, and the initial clinical presentations, diagnostic laboratory data, details of the underlying comorbidities, and initial management recommendations based on 2009 World Health Organization (WHO) guidelines were used to evaluate prognostic indicators of critical outcomes in dengue patients. Dengue patients from another regional hospital were used to evaluate accuracy. A group B (4 points) classification, temperature < 38.5 °C (1 point), lower diastolic blood pressure (1 point), prolonged activated partial thromboplastin time (aPTT) (2 points), and elevated liver enzymes (1 point) were included in the scoring system. The area under the receiver operating characteristic curve of the clinical model was 0.933 (95% confidence interval [CI]: 0.905–0.960). The tool had good predictive value and clinical applicability for identifying patients with critical outcomes.

Demographic characteristics, clinical symptoms, biochemical markers and probability of occurrence of severe dengue: A multicenter hospital-based study in Bangladesh

Establishing reliable early warning models for severe dengue cases is a high priority to facilitate triage in dengue-endemic areas and optimal use of limited resources. However, few studies have identified the complex interactive relationship between potential risk factors and severe dengue. This research aimed to assess the potential risk factors and detect their high-order combinative effects on severe dengue. A structured questionnaire was used to collect detailed dengue outbreak data from eight representative hospitals in Dhaka, Bangladesh, in 2019. Logistic regression and machine learning models were used to examine the complex effects of demographic characteristics, clinical symptoms, and biochemical markers on severe dengue. A total of 1,090 dengue cases (158 severe and 932 non-severe) were included in this study. Dyspnoea (Odds Ratio [OR] = 2.87, 95% Confidence Interval [CI]: 1.72 to 4.77), plasma leakage (OR = 3.61, 95% CI: 2.12 to 6.15), and hemorrhage (OR = 2.33, 95% CI: 1.46 to 3.73) were positively and significantly associated with the occurrence of severe dengue. Classification and regression tree models showed that the probability of occurrence of severe dengue cases ranged from 7% (age >12.5 years without plasma leakage) to 92.9% (age ≤12.5 years with dyspnoea and plasma leakage). The random forest model indicated that age was the most important factor in predicting severe dengue, followed by education, plasma leakage, platelet, and dyspnoea. The research provides new evidence to identify key risk factors contributing to severe dengue cases, which could be beneficial to clinical doctors to identify and predict the severity of dengue early.

Sequential Organ Failure Assessment (SOFA) Score for predicting mortality in patients with sepsis in Vietnamese intensive care units: a multicentre, cross-sectional study

OBJECTIVES

To compare the accuracy of the Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) Scores in predicting mortality among intensive care unit (ICU) patients with sepsis in a low-income and middle-income country.

DESIGN

A multicentre, cross-sectional study.

SETTING

A total of 15 adult ICUs throughout Vietnam.

PARTICIPANTS

We included all patients aged ≥18 years who were admitted to ICUs for sepsis and who were still in ICUs from 00:00 to 23:59 of the specified study days (ie, 9 January, 3 April, 3 July and 9 October of the year 2019).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was hospital all-cause mortality (hospital mortality). We also defined the secondary outcome as all-cause deaths in the ICU (ICU mortality).

RESULTS

Of 252 patients, 40.1% died in hospitals, and 33.3% died in ICUs. SOFA Score (areas under the receiver operating characteristic curve (AUROC): 0.688 (95% CI 0.618 to 0.758); cut-off value≥7.5; P_AUROC<0.001) and APACHE II Score (AUROC: 0.689 (95% CI 0.622 to 0.756); cut-off value ≥20.5; P_AUROC<0.001) both had a poor discriminatory ability for predicting hospital mortality. However, the discriminatory ability for predicting ICU mortality of SOFA (AUROC: 0.713 (95% CI 0.643 to 0.783); cut-off value≥9.5; P_AUROC<0.001) was fair and was better than that of APACHE II Score (AUROC: 0.672 (95% CI 0.603 to 0.742); cut-off value≥18.5; P_AUROC<0.001). A SOFA Score≥8 (adjusted OR (AOR): 2.717; 95% CI 1.371 to 5.382) and an APACHE II Score≥21 (AOR: 2.668; 95% CI 1.338 to 5.321) were independently associated with an increased risk of hospital mortality. Additionally, a SOFA Score≥10 (AOR: 2.194; 95% CI 1.017 to 4.735) was an independent predictor of ICU mortality, in contrast to an APACHE II Score≥19, for which this role did not.

CONCLUSIONS

In this study, SOFA and APACHE II Scores were worthwhile in predicting mortality among ICU patients with sepsis. However, due to better discrimination for predicting ICU mortality, the SOFA Score was preferable to the APACHE II Score in predicting mortality.Clinical trials registry - India: CTRI/2019/01/016898.

Adjusting for misclassification of an exposure in an individual participant data meta-analysis

A common problem in the analysis of multiple data sources, including individual participant data meta-analysis (IPD-MA), is the misclassification of binary variables. Misclassification may lead to biased estimators of model parameters, even when the misclassification is entirely random. We aimed to develop statistical methods that facilitate unbiased estimation of adjusted and unadjusted exposure-outcome associations and between-study heterogeneity in IPD-MA, where the extent and nature of exposure misclassification may vary across studies. We present Bayesian methods that allow misclassification of binary exposure variables to depend on study- and participant-level characteristics. In an example of the differential diagnosis of dengue using two variables, where the gold standard measurement for the exposure variable was unavailable for some studies which only measured a surrogate prone to misclassification, our methods yielded more accurate estimates than analyses naive with regard to misclassification or based on gold standard measurements alone. In a simulation study, the evaluated misclassification model yielded valid estimates of the exposure-outcome association, and was more accurate than analyses restricted to gold standard measurements. Our proposed framework can appropriately account for the presence of binary exposure misclassification in IPD-MA. It requires that some studies supply IPD for the surrogate and gold standard exposure, and allows misclassification to follow a random effects distribution across studies conditional on observed covariates (and outcome). The proposed methods are most beneficial when few large studies that measured the gold standard are available, and when misclassification is frequent.

Comprehensive analysis of multivariable models for predicting severe dengue prognosis: systematic review and meta-analysis

Dengue fever has often been confused with other febrile diseases, with deterioration occurring in the later state. Many predictive models for disease progression have been developed, but there is no definite statistical model for clinical use yet. We retrieved relevant articles through Global Health, EMBASE, MEDLINE and CINAHL Plus. The Prediction Model Risk of Bias Assessment Tool was adopted to assess potential bias and applicability. Statistical analysis was performed using Meta-DiSc software (version 1.4). Of 3184 research studies, 22 were included for the systematic review, of which 17 were selected for further meta-analysis. The pooled data of predictive accuracy was as follows: the sensitivity was 0.88 (95% CI 0.86 to 0.89), the specificity was 0.60 (95% CI 0.59 to 0.60), the positive likelihood ratio was 2.83 (95% CI 2.38 to 3.37), the negative likelihood ratio was 0.20 (95% CI 0.14 to 0.0.29) and the diagnostic OR was 16.31 (95% CI 10.25 to 25.94). The area under the summary receiver operating characteristic curve value was 0.86 (SE=0.02) with 0.79 (SE=0.02) of the Cochran Q test value. The overall predictive power of models in this study was relatively high. With careful adaption and standardization, the implementation of predictive models for severe dengue could be practical in actual clinical settings.

Dengue incidence and length of viremia by RT-PCR in a prospective observational community contact cluster study from 2005-2009 in Indonesia

BACKGROUND

Dengue has become a major global health threat since being recognized three centuries ago. Important gaps remain in understanding the transmission dynamics of dengue virus (DENV) infection. This study reports the results of a prospective observational cluster study that investigated the incidence of symptomatic and asymptomatic infections and length of viremia among close community contacts of hospitalized DENV-infected patients.

METHODOLOGY/PRINCIPAL FINDINGS

Between 2005 and 2009, dengue-confirmed cases (n = 97) admitted to Hasan Sadikin Hospital in Bandung, Indonesia, were enrolled as index cases. Subsequently, twenty close community contacts (n = 1928) living with and around the index cases were included and followed up for up to 14 days. Body temperature was measured daily; blood samples were collected every 3-4 days and when reported fever. DENV infection was confirmed using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR), IgM rapid test, and Enzyme-linked Immunosorbent Assay (ELISA). Among the 1928 community contacts, a total of 72 (3.7%) acute DENV infections were diagnosed, which equates to an incidence of 636 cases per 1,000 person-years (95% Confidence interval (CI) 588 to 687 cases per 1,000 person-years). Twenty-nine cases (40%) were symptomatic (22 dengue fever (DF) & 7 dengue hemorrhagic fever (DHF)), and 43 (60%) were asymptomatic. Primary and secondary DENV infections were detected in 18 (25%) and 54 (75%) subjects. Among the RT-PCR positives, viremia was observed as early as seven days before fever onset and converted to negative as late as seven days after the onset of fever.

CONCLUSIONS

DENV infections are common among close community contacts of hospitalized dengue patients. The high number of asymptomatic infections and the observation that viremia precedes the onset of fever for up to seven days highlight the importance of unrecognized dengue transmission and the need for improved transmission control.

Hemogram indicators in children aged 7–14 years with new coronavirus infection

The research is focused on the evaluation of a general blood test in children with a new coronavirus infection, depending on the severity of the disease. 107 patients with virus-identified new coronavirus infection aged 7–14 years were examined. 19 (17.8%) were diagnosed with asymptomatic, 69 (64.4%) mild, and 19 (17.8%) moderate COVID-19. The control group is represented by 75 healthy children. The hemogram indicators in each group were analyzed, a correlation analysis of the red and white blood cell counts with the severity of the disease was carried out. In children with a new coronavirus infection, a significant decrease in the blood hemoglobin relative to the control group was revealed, although not exceeding the normal values. An inverse correlation was established between a decrease in the WBC and absolute lymphocytes count and the severity of clinical manifestations of the disease.

Clinical-epidemiological characteristics of deaths due to dengue during an outbreak in northern Peru

Motivation for the study. To describe the characteristics of patients who died from severe dengue fever during the 2017 El Niño in Piura. Main findings. Mortality from severe dengue was higher in adult women. First contact with healthcare took place mostly in higher level hospitals. Admission to a specialized unit was late for severe dengue cases. Implications. Control of dengue fever involves several aspects, such as, access to health, prevention, water availability, vector control and education; therefore, it is important to strengthen public health policies in this regard. In order to achieve this goal, local and central government sectors must be involved.

Development of a rapid assay system for detecting antibody-dependent enhancement of dengue virus infection

Antibody-dependent enhancement (ADE) is one of the pathogenic mechanisms related to disease severity in dengue virus infection. Conventional assays for detecting ADE activity usually require several days. In this study, we established a rapid assay system to evaluate ADE activity in dengue-seropositive samples using single round infectious particles (SRIPs). Human Fc-gamma receptor-bearing cells (K562 and Mylc cells) were infected with SRIP antigen in the presence of human serum samples to measure ADE activity. Two assay protocols were introduced: (i) rapid assay with 5 h of incubation, and (ii) semi-rapid assay with 24 h of incubation. The rapid assay requires a large quantity of SRIP antigen and gives results in half a day. Although the semi-rapid assay requires slightly more than a day, it can be performed using only a small amount of SRIP. Interestingly, the range of the number of Mylc cells required for the semi-rapid assay was wider than that of K562 cells. Significant correlations were observed between the rapid and semi-rapid assays for both cell types. Although it is difficult to judge which protocol best reflects the current immune status in vivo, both assays could rapidly provide valuable information regarding the risk assessment for severe diseases.

Paediatric dengue shock syndrome and acute respiratory failure: a single-centre retrospective study

OBJECTIVE

Dengue shock syndrome (DSS) is a serious health condition leading to paediatric intensive care unit (PICU) admissions and deaths in tropical countries. Acute respiratory failure (ARF) is associated with DSS and is a major cause of dengue deaths. We aimed to identify risk factors associated with ARF in children with DSS.

METHODS

We retrospectively reviewed children with DSS admitted to a PICU from 2010 to 2020 at a tertiary level hospital in Bangkok, Thailand. Patient characteristics, clinical parameters and laboratory data were collected. Multivariable logistic regression analysis was used to identify factors associated with ARF.

RESULTS

Twenty-six (43.3%) of 60 children with DSS developed ARF and 6 did not survive to day 28. The median (IQR) age was 8.1 years (IQR 4.0-11.0). Fluid accumulation during the first 72 hours of PICU admission was greater in the ARF group compared with the non-ARF group (12.2% (IQR 7.6-21.7) vs 8.3% (IQR 4.4-13.3), p=0.009). In a multivariate analysis at 72 hours post PICU admission, the presence of ˃15% fluid accumulation was independently associated with ARF (adjusted OR 5.67, 95% CI 1.24 to 25.89, p=0.025).

CONCLUSION

ARF is an important complication in children with DSS. A close assessment of patient fluid status is essential to identify patients at risk of ARF. Once the patient is haemodynamically stable and leakage slows, judicious fluid management is required to prevent ARF.

Predictive validity of the quick Sequential Organ Failure Assessment (qSOFA) score for the mortality in patients with sepsis in Vietnamese intensive care units

Background

The simple scoring systems for predicting the outcome of sepsis in intensive care units (ICUs) are few, especially for limited-resource settings. Therefore, this study aimed to evaluate the accuracy of the quick Sequential (Sepsis-Related) Organ Failure Assessment (qSOFA) score in predicting the mortality of ICU patients with sepsis in Vietnam.

Methods

We did a multicenter cross-sectional study of patients with sepsis (≥18 years old) presenting to 15 adult ICUs throughout Vietnam on the specified days (i.e., 9th January, 3rd April, 3rd July, and 9th October) representing the different seasons of 2019. The primary and secondary outcomes were the hospital and ICU all-cause mortalities, respectively. The area under the receiver operating characteristic curve (AUROC) was calculated to determine the discriminatory ability of the qSOFA score for deaths in the hospital and ICU. The cut-off value of the qSOFA scores was determined by the receiver operating characteristic curve analysis. Upon ICU admission, factors associated with the hospital and ICU mortalities were assessed in univariable and multivariable logistic models.

Results

Of 252 patients, 40.1% died in the hospital, and 33.3% died in the ICU. The qSOFA score had a poor discriminatory ability for both the hospital (AUROC: 0.610 [95% CI: 0.538 to 0.681]; cut-off value: ≥2.5; sensitivity: 34.7%; specificity: 84.1%; P_AUROC = 0.003) and ICU (AUROC: 0.619 [95% CI: 0.544 to 0.694]; cutoff value: ≥2.5; sensitivity: 36.9%; specificity: 83.3%; P_AUROC = 0.002) mortalities. However, multivariable logistic regression analyses show that the qSOFA score of 3 was independently associated with the increased risk of deaths in both the hospital (adjusted odds ratio, AOR: 3.358; 95% confidence interval, CI: 1.756 to 6.422) and the ICU (AOR: 3.060; 95% CI: 1.651 to 5.671).

Conclusion

In our study, despite having a poor discriminatory value, the qSOFA score seems worthwhile in predicting mortality in ICU patients with sepsis in limited-resource settings.

Clinical trial registration

Clinical trials registry–India: CTRI/2019/01/016898

A cross-sectional study to assess the epidemiological situation and associated risk factors of dengue fever; knowledge, attitudes, and practices about dengue prevention in Khyber Pakhtunkhwa Province, Pakistan

Background

Dengue fever has been responsible for around 12 countrywide large outbreaks in Pakistan, resulting in 286,262 morbidities and 1,108 deaths. Khyber Pakhtunkhwa (KP) is the most recently impacted province. This study aimed to investigate the molecular, epidemiological, and potential elements that contribute to increasing dengue transmission patterns, and knowledge, attitude, and practice (KAP) toward dengue in KP province.

Method

This cross-sectional community-based study was conducted (June-December, 2021) in two phases. Phase I involved the epidemiological (n = 5,242) and molecular analysis of DENV in 500 randomly collected blood samples of the 2021 dengue outbreak in KP. Phase II focused on assessing dengue-KAP levels in healthy communities (n = 14,745, aged >18 years), adopting a cross-sectional clustered multistage sampling in eight districts (dengue-hotspot vs. non-hotspot) of KP. Chi-square tests and logistic regression analysis were applied.

Results

Peshawar district had the highest dengue cases (60.0%) associated with the predominant co-circulation of DENV-2 (45.8%) and DENV-3 (50.4%) serotypes. A rise in cases was reported in October (41.8%) followed by September (27.9%) and August (14.4%; p < 0.001). Males (63.7%, p < 0.001) and individuals aged 16–30 years (37.0%, p < 0.001) were highly affected. General workers (18.0%), families with a monthly income of 10,000–20,000 Pak rupees (50.5%), unmarried (71.0%), uneducated (31%), families with higher human density (>10 individuals per household), and those (29.0%) who faced power outages for more than 7/24 h were the most affected. Moreover, co-morbidities like renal failure and bronchial asthma were associated with disease severity. A community survey on KAP revealed that an average of 74, 60, and 43% of the participants demonstrated good knowledge, attitudes, and dengue preventive practices, respectively.

Conclusion

Multiple poor socioeconomic elements are influencing dengue fever transmission in the province. Higher KAP levels may explain the low frequency of dengue in non-hotspot districts. Our study emphasizes the need for effective and long-term public health education, strengthened vector surveillance, and expanded laboratory capacity for better diagnosis and management of dengue cases to better predict the burden and seasonality of disease in the country.

Risk and predictive factors for severe dengue infection: A systematic review and meta-analysis

Background

Dengue is a major public health issue worldwide and severe dengue (SD) is life threatening. It is critical to triage patients with dengue infection in the early stage. However, there is limited knowledge on early indicators of SD. The objective of this study is to identify risk factors for the prognosis of SD and try to find out some potential predictive factors for SD from dengue fever (DF) in the early of infection.

Methods

The PubMed, Cochrane Library and Web of Science databases were searched for relevant studies from June 1999 to December 2020. The pooled odds ratio (OR) or standardized mean difference (SMD) with 95% confidence intervals (CI) of identified factors was calculated using a fixed or random effect model in the meta-analysis. Tests for heterogeneity, publication bias, subgroup analyses, meta-regression, and a sensitivity analysis were further performed.

Findings

A total of 6,848 candidate articles were retrieved, 87 studies with 35,184 DF and 8,173 SD cases met the eligibility criteria. A total of 64 factors were identified, including population and virus characteristics, clinical symptoms and signs, laboratory biomarkers, cytokines, and chemokines; of these factors, 34 were found to be significantly different between DF and SD, while the other 30 factors were not significantly different between the two groups after pooling the data from the relevant studies. Additionally, 9 factors were positive associated with SD within 7 days after illness when the timing subgroup analysis were performed.

Conclusions

Practical factors and biomarkers for the identification of SD were established, which will be helpful for a prompt diagnosis and early effective treatment for those at greatest risk. These outcomes also enhance our knowledge of the clinical manifestations and pathogenesis of SD.

Rescue therapy with intravenous immunoglobulin in severe refractory dengue: A pilot study

Background

Severe dengue causes more than 22,000 deaths annually worldwide. Complicated dengue has high mortality of 44-72%. Disordered immune system with capillary leak and thrombocytopenia are hallmark of complicated dengue. Intravenous immunoglobulin (IV Ig) therapy has shown to be effective in complicated dengue in pediatric age group with refractory shock, but studies in adults are lacking. Its immunoresuscitative role is not yet fully explored in critically ill patients with severe dengue.

Methods

This is retrospective observational study of patients with complicated dengue fever who were administered IV Ig therapy in a tertiary care hospital of southern India from 01 Jan 2018 to 31 Dec 2019.

Results

A total of 999 patients with dengue were admitted; 754 (75.47%) were males, and 245 (24.53%) were females. A total of 402 (40.24%) patients presented with warning signs. Bleeding was seen in 121 patients (12.11%); 102 (10.21%) had shock; 29 (2.90%) had acute kidney injury and 24 (2.40%) had adult respiratory distress syndrome. Overall, four people died (mortality rate: 0.40%). IV Ig in the dose of 0.4 g/kg for 5 days was used in 13 critically ill patients where standard therapy failed, 9 patients with refractory shock (which included three with myocarditis with refractory shock), 2 with encephalitis, 2 in hemophagocytic lymphohistiocytosis. Two patients died, one with myocarditis with refractory shock and another with refractory shock.

Conclusion

IV Ig therapy in critically ill patients with complicated dengue can be used as a rescue therapy.

Knowledge, Attitude, and Practices towards Dengue Fever among University Students of Dhaka City, Bangladesh

Dhaka has become the worst affected city in Bangladesh regarding dengue fever (DF). A large number of university students are residing in this city with a high DF risk. This cross-sectional study was conducted to assess the DF status and responses among these students through their Knowledge, Attitude, and Practices (KAP) survey. A total of 625 students participated in an online self-reported survey. Statistical analyses were performed to assess the status and KAP regarding DF. University students from the city perceived their living places as moderately safe (45.28%) against DF, whereas about 20% reported their DF infection history. Some of these students had exemplary DF knowledge (66.72%), attitude (89.28%), and practices (68.32%). However, many of them were also observed with a lack of knowledge about this disease’s infectious behavior, recognizing Aedes mosquito breeding sites, multiple infection cases, and the risk of DF viral infection during pregnancy. Fair correlations (p < 0.001) were determined in the KAP domain. Gender, residential unit, major, and dengue-relevant subjects were found to be significant predictors (p < 0.05) of KAP level in the univariate analysis. Major subject and residential units remained significant predictors of overall KAP level in further multiple analysis. This study revealed the urgency of infectious disease-related subjects and the relevant demonstration into the university curriculum. The study’s findings can assist the university, government and non-governmental organizations, and the health and social workers to prepare a comprehensive dengue response and preparedness plan.

Knowledge gaps in the epidemiology of severe dengue impede vaccine evaluation

The most severe consequences of dengue virus infection include shock, haemorrhage, and major organ failure; however, the frequency of these manifestations varies, and the relative contribution of pre-existing anti-dengue virus antibodies, virus characteristics, and host factors (including age and comorbidities) are not well understood. Reliable characterisation of the epidemiology of severe dengue first depends on the use of consistent definitions of disease severity. As vaccine trials have shown, severe dengue is a crucial interventional endpoint, yet the infrequency of its occurrence necessitates the inclusion of thousands of study participants to appropriately compare its frequency among participants who have and have not been vaccinated. Hospital admission is frequently used as a proxy for severe dengue; however, lack of specificity and variability in clinical practices limit the reliability of this approach. Although previous infection with a dengue virus is the best characterised risk factor for developing severe dengue, the influence of the timing between dengue virus infections and the sequence of dengue virus infections on disease severity is only beginning to be elucidated. To improve our understanding of the diverse factors that shape the clinical spectrum of disease resulting from dengue virus infection, prospective, community-based and clinic-based immunological, virological, genetic, and clinical studies across a range of ages and geographical regions are needed.

Impacts of El Niño Southern Oscillation on the dengue transmission dynamics in the Metropolitan Region of Recife, Brazil

Background:

This research addresses two questions: (1) how El Niño Southern Oscillation (ENSO) affects climate variability and how it influences dengue transmission in the Metropolitan Region of Recife (MRR), and (2) whether the epidemic in MRR municipalities has any connection and synchronicity.

Methods:

Wavelet analysis and cross-correlation were applied to characterize seasonality, multiyear cycles, and relative delays between the series. This study was developed into two distinct periods. Initially, we performed periodic dengue incidence and intercity epidemic synchronism analyses from 2001 to 2017. We then defined the period from 2001 to 2016 to analyze the periodicity of climatic variables and their coherence with dengue incidence.

Results:

Our results showed systematic cycles of 3-4 years with a recent shortening trend of 2-3 years. Climatic variability, such as positive anomalous temperatures and reduced rainfall due to changes in sea surface temperature (SST), is partially linked to the changing epidemiology of the disease, as this condition provides suitable environments for the Aedes aegypti lifecycle.

Conclusion:

ENSO may have influenced the dengue temporal patterns in the MRR, transiently reducing its main way of multiyear variability (3-4 years) to 2-3 years. Furthermore, when the epidemic coincided with El Niño years, it spread regionally and was highly synchronized.

Severe dengue in adults and children, Ouagadougou (Burkina Faso), West Africa, October 2015–January 2017

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Severe dengue was common in this sudy.

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In contrast to multiple prior studies, the risk of severe dengue was greater for patients with primary dengue compared to those with secondary infection.

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Additional risk factors for severe dengue included age, male sex, haemoglobin S, diabetes, and hypertension.  Case mapping showed that dengue cases were more concentrated  in sectors located in the centre of the city and close to the health centres.

Introduction

Although dengue is the most common arbovirus infection worldwide, studies of severe dengue in Africa are lacking, and risk factors for severe dengue have been insufficiently described. This study was conducted in the context of the 2016 dengue epidemic in Burkina Faso to determine the prevalence of severe dengue, identify factors associated with severe dengue, and perform mapping of dengue cases in the country's capital, Ouagadougou.

Methods

This cross-sectional study was conducted from November 2015 to January 2017. Data were collected in 15 public and private health centres, and included sociodemographic, clinical and patient outcome variables. Dengue was diagnosed using SD Bioline Dengue Duo rapid diagnostic tests. Data were analysed using Epi-Info Version 7. Logistic regression was used to identify predictors of severe dengue. P<0.05 was considered significant. Dengue case mapping was performed using Geographic Information System software (ArcGIS).

Results

Of the 811 patients who tested positive for dengue, 609 (75%) had early dengue (AgNS1 positive) and 272 (33.5%) had severe dengue. Patient age ranged from 1 to 83 years (median 30.5 years) and 393 (48.3%) were female. Renal failure (13.1%) and severe bleeding (10.6%) were the most common signs of severe dengue. Risk factors for severe dengue included age, male sex, haemoglobin S, diabetes, hypertension, and primary dengue. Dengue cases were more concentrated  in sectors located in the centre of the city and close to the health centres.

Conclusion

Dengue is increasingly common in Africa and factors associated with severity should be sought systematically as soon as a patient tests positive. Additional studies are needed to determine if the factors found to be associated with severity can be used to identify patients at risk for dengue-related complications, and to provide early and specialized management to reduce morbidity and mortality related to dengue in Africa.

Clinical predictors of severe dengue: a systematic review and meta-analysis

Background

Severe dengue is a life-threatening complication; rapid identification of these cases, followed by adequate management is crucial to improve the clinical prognosis. Therefore, this study aimed to identify risk factors and predictors of severe dengue.

Methods

A literature search for studies reporting risk factors of severe dengue among individuals with dengue virus infection was conducted in PubMed, Scopus and Web of Science database from inception to December 31, 2020. Pooled odds ratios (ORs) for patients’ demographic characteristics, co-morbidities, and warning signs were estimated using an inverse variance heterogeneity model.

Results

We included 143 articles in the meta-analysis from a total of 13 090 articles retrieved from the literature search. The risk factors of severe dengue were: being a child [OR = 1.96; 95% confidence interval (CI): 1.22–3.13], secondary infection (OR = 3.23; 95% CI: 2.28–4.57), and patients with pre-existing diabetes (OR = 2.88; 95% CI: 1.72–4.81) and renal disease (OR = 4.54; 95% CI: 1.55–13.31). Warning signs strongly associated with severe disease were increased haematocrit with a concurrent decrease in platelet count (OR = 5.13; 95% CI: 1.61–16.34), abdominal pain (OR = 2.00; 95% CI: 1.49–2.68), lethargy (OR = 2.73; 95% CI: 1.05–7.10), vomiting (OR = 1.80; 95% CI: 1.43–2.26), hepatomegaly (OR = 5.92; 95% CI: 3.29–10.66), ascites (OR = 6.30; 95% CI: 3.75–10.60), pleural effusion (OR = 5.72; 95% CI: 3.24–10.10) and melena (OR = 4.05; 95% CI: 1.64–10.00).

Conclusions

Our meta-analysis identified children, secondary infection, diabetes and renal disease(s) as important predictors of severe dengue. Our finding also supports the predictive ability of the WHO warning signs to identify severe dengue. These findings are useful for clinicians to identify severe dengue for management and timely interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-021-00908-2.

Factors relating to mortality in septic patients in Vietnamese intensive care units from a subgroup analysis of MOSAICS II study

Sepsis is the most common cause of in-hospital deaths, especially from low-income and lower-middle-income countries (LMICs). This study aimed to investigate the mortality rate and associated factors from sepsis in intensive care units (ICUs) in an LMIC. We did a multicenter cross-sectional study of septic patients presenting to 15 adult ICUs throughout Vietnam on the 4 days representing the different seasons of 2019. Of 252 patients, 40.1% died in hospital and 33.3% died in ICU. ICUs with accredited training programs (odds ratio, OR: 0.309; 95% confidence interval, CI 0.122-0.783) and completion of the 3-h sepsis bundle (OR: 0.294; 95% CI 0.083-1.048) were associated with decreased hospital mortality. ICUs with intensivist-to-patient ratio of 1:6 to 8 (OR: 4.533; 95% CI 1.621-12.677), mechanical ventilation (OR: 3.890; 95% CI 1.445-10.474) and renal replacement therapy (OR: 2.816; 95% CI 1.318-6.016) were associated with increased ICU mortality, in contrast to non-surgical source control (OR: 0.292; 95% CI 0.126-0.678) which was associated with decreased ICU mortality. Improvements are needed in the management of sepsis in Vietnam such as increasing resources in critical care settings, making accredited training programs more available, improving compliance with sepsis bundles of care, and treating underlying illness and shock optimally in septic patients.

Analysis of Hospitalized and Severe Dengue Cases Over the 6 years of Follow-up of the Tetravalent Dengue Vaccine (CYD-TDV) Efficacy Trials in Asia and Latin America

Background

CYD-TDV, a live, attenuated, tetravalent dengue vaccine, has been approved for the prevention of symptomatic dengue in previously dengue exposed individuals. This post hoc analysis assessed hospitalized and severe virologically confirmed dengue (VCD) over the complete 6-year follow-up of 3 CYD-TDV efficacy studies (CYD14, CYD15, and CYD23/CYD57).

Methods

The main outcomes were hazard ratios (HRs) for hospitalized or severe VCD by baseline dengue serostatus, focusing on those who were seropositive, and by age at immunization (<9 years/≥9 years). Baseline dengue serostatus was measured or inferred using several methods. Hospitalized VCD cases were characterized in terms of clinical signs and symptoms and wild-type viremia level. Antibody persistence was assessed up to 5 years after the last injection.

Results

In those aged ≥9 years and baseline seropositive, CYD-TDV protected against hospitalized and severe VCD over 6 years compared to placebo (HR [95% confidence interval] multiple imputation from month 0 method, .19 [.12–.30] and .15 [.06–.39]; other methods were consistent). Vaccine protection was observed over the different study periods, being highest during the first 2 years. Evidence for a decreased risk of hospitalized and severe VCD was also observed in seropositive participants aged 6–8 years. Clinical signs and symptoms, and quantified dengue viremia from participants with hospitalized VCD were comparable between groups.

Conclusions

CYD-TDV demonstrated robust protection against hospitalized and severe VCD over the entire 6-year follow-up in participants who were seropositive and ≥9 years old. Protection was also observed in seropositive 6–8 year-olds.

Clinical Trials Registration: NCT00842530, NCT01983553, NCT01373281, NCT01374516.

Fatal outcomes of imported dengue fever in adult travelers from non-endemic areas are associated with primary infections

BACKGROUND

The case-fatality rate of dengue in travelers is low. Secondary dengue virus (DENV) infections are considered a risk factor for fatal outcome in endemic populations; however, the impact of secondary infections on mortality in travelers has not been studied systematically. We performed a descriptive analysis of case reports of dengue fatalities in travelers.

METHODS

We searched Medline for clinical case reports, using the free terms and MeSH headings: 'Dengue' OR 'Severe Dengue' AND 'Travel-Related Illness' OR 'travel' AND 'Mortality' OR 'Fatal Outcome'. We analyzed case reports of fatal dengue in returning travelers published from 1995 to 2020, with the objective to detail risk factors for dengue mortality in this population. We verified the authors' classifications of primary or secondary dengue infections; infections were considered as primary by absence of anti-DENV immunoglobulin (Ig)G or by IgM-to-IgG ratios greater than or equal to 1.8 in the first 7 days post symptom onset.

RESULTS

We identified nine detailed reports of dengue with fatal outcome among travelers from non-endemic countries. Eight fatalities were female. The median age was 32 years (range 21-63). Out of nine fatal cases, seven travelers had a primary DENV infection, one had a secondary infection and, in one, these data were not reported. The infecting DENV serotypes were DENV-1 (n = 2), DENV-2 (n = 2) and DENV-3 (n = 3); DENV-1 or 2 (n = 1) and in one case, the serotype could not be determined.

CONCLUSIONS

Dengue-related deaths in travelers are rare. Most dengue cases in travelers are primary infections. Contrary to prevailing conceptions, we found that fatal outcomes of dengue in travelers from non-endemic countries were reported mainly with primary DENV infections. We alert health care providers that primary DENV infections are not always harmless and that in adult travelers from non-endemic countries, primary infections may contribute more to dengue-related mortality than secondary infections.

Risk predictors of progression to severe disease during the febrile phase of dengue: a systematic review and meta-analysis

BACKGROUND

The ability to accurately predict early progression of dengue to severe disease is crucial for patient triage and clinical management. Previous systematic reviews and meta-analyses have found significant heterogeneity in predictors of severe disease due to large variation in these factors during the time course of the illness. We aimed to identify factors associated with progression to severe dengue disease that are detectable specifically in the febrile phase.

METHODS

We did a systematic review and meta-analysis to identify predictors identifiable during the febrile phase associated with progression to severe disease defined according to WHO criteria. Eight medical databases were searched for studies published from Jan 1, 1997, to Jan 31, 2020. Original clinical studies in English assessing the association of factors detected during the febrile phase with progression to severe dengue were selected and assessed by three reviewers, with discrepancies resolved by consensus. Meta-analyses were done using random-effects models to estimate pooled effect sizes. Only predictors reported in at least four studies were included in the meta-analyses. Heterogeneity was assessed using the Cochrane Q and I2 statistics, and publication bias was assessed by Egger's test. We did subgroup analyses of studies with children and adults. The study is registered with PROSPERO, CRD42018093363.

FINDINGS

Of 6643 studies identified, 150 articles were included in the systematic review, and 122 articles comprising 25 potential predictors were included in the meta-analyses. Female patients had a higher risk of severe dengue than male patients in the main analysis (2674 [16·2%] of 16 481 vs 3052 [10·5%] of 29 142; odds ratio [OR] 1·13 [95% CI 1·01-1·26) but not in the subgroup analysis of studies with children. Pre-existing comorbidities associated with severe disease were diabetes (135 [31·3%] of 431 with vs 868 [16·0%] of 5421 without; crude OR 4·38 [2·58-7·43]), hypertension (240 [35·0%] of 685 vs 763 [20·6%] of 3695; 2·19 [1·36-3·53]), renal disease (44 [45·8%] of 96 vs 271 [16·0%] of 1690; 4·67 [2·21-9·88]), and cardiovascular disease (nine [23·1%] of 39 vs 155 [8·6%] of 1793; 2·79 [1·04-7·50]). Clinical features during the febrile phase associated with progression to severe disease were vomiting (329 [13·5%] of 2432 with vs 258 [6·8%] of 3797 without; 2·25 [1·87-2·71]), abdominal pain and tenderness (321 [17·7%] of 1814 vs 435 [8·1%] of 5357; 1·92 [1·35-2·74]), spontaneous or mucosal bleeding (147 [17·9%] of 822 vs 676 [10·8%] of 6235; 1·57 [1·13-2·19]), and the presence of clinical fluid accumulation (40 [42·1%] of 95 vs 212 [14·9%] of 1425; 4·61 [2·29-9·26]). During the first 4 days of illness, platelet count was lower (standardised mean difference -0·34 [95% CI -0·54 to -0·15]), serum albumin was lower (-0·5 [-0·86 to -0·15]), and aminotransferase concentrations were higher (aspartate aminotransferase [AST] 1·06 [0·54 to 1·57] and alanine aminotransferase [ALT] 0·73 [0·36 to 1·09]) among individuals who progressed to severe disease. Dengue virus serotype 2 was associated with severe disease in children. Secondary infections (vs primary infections) were also associated with severe disease (1682 [11·8%] of 14 252 with vs 507 [5·2%] of 9660 without; OR 2·26 [95% CI 1·65-3·09]). Although the included studies had a moderate to high risk of bias in terms of study confounding, the risk of bias was low to moderate in other domains. Heterogeneity of the pooled results varied from low to high on different factors.

INTERPRETATION

This analysis supports monitoring of the warning signs described in the 2009 WHO guidelines on dengue. In addition, testing for infecting serotype and monitoring platelet count and serum albumin, AST, and ALT concentrations during the febrile phase of illness could improve the early prediction of severe dengue.

FUNDING

Wellcome Trust, National Institute for Health Research, Collaborative Project to Increase Production of Rural Doctors, and Royal Thai Government.

Antibody-dependent enhancement representing in vitro infective progeny virus titer correlates with the viremia level in dengue patients

Dengue virus (DENV) causes dengue fever (DF) and dengue hemorrhagic fever in humans. Some DF patients suddenly develop severe symptoms around the defervescent period. Although the pathogenic mechanism of the severe symptoms has not been fully elucidated, the viremia level in the early phase has been shown to correlate with the disease severity. One of the hypotheses is that a phenomenon called antibody-dependent enhancement (ADE) of infection leads to high level of viremia. To examine the plausibility of this hypothesis, we examined the relationship between in vitro ADE activity and in vivo viral load quantity in six patients with dengue diseases. Blood samples were collected at multiple time points between the acute and defervescent phases, and the balance between neutralizing and enhancing activities against the autologous and prototype viruses was examined. As the antibody levels against DENV were rapidly increased, ADE activity was decreased over time or partially maintained against some viruses at low serum dilution. In addition, positive correlations were observed between ADE activity representing in vitro progeny virus production and viremia levels in patient plasma samples. The measurement of ADE activity in dengue-seropositive samples may help to predict the level of viral load in the subsequent DENV infection.

Factors associated with clinical outcomes of pediatric dengue shock syndrome admitted to pediatric intensive care unit: A retrospective cohort study

Background

Dengue shock syndrome (DSS) in children is a challenging infectious disease due to its high mortality rate. Several factors can contribute to the DSS patients’ outcomes. Here we defined factors associated with clinical outcomes of patients with DSS in Pediatric Intensive Care Unit (PICU).

Methods

We retrospectively collected data from January 2016 to May 2020 of patients who had been diagnosed with DSS and admitted to PICU in our tertiary referral hospital. Bivariate analysis and logistic regression were used to evaluate independent predictors of the study outcomes.

Results

Overall, 146 patients were enrolled in this study, including 53.4% males and 46.6% females. The mortality rate during the study period was 5.5%. Fluid overload percentage, shock condition at PICU admission, DIC, and AKI were independent predictors for DSS mortality in logistic regression test with p < 0.05. There were several factors correlated with prolonged stay, including disseminated intravascular coagulation (DIC) (RR 15.26; 95% CI: 4.97–46.81), and nutritional status (RR 16.47; 95% CI: 3.72–72.9).

Conclusion

Fluid overload percentage, shock condition at PICU admission, DIC, and AKI are independent predictors for DSS mortality. Several factors contribute to prolonged PICU stay, including DIC and nutritional status.

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Dengue shock syndrome is still a major problem in childrens' health in Indonesia.

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Infection and fluid overload should to be concerned to prevent prolonged PICU stay.

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The importance of increasing referral response times from previous hospitals in dengue shock syndrome cases.

Social, health system and clinical determinants of fever mortality during an outbreak of dengue fever in Kerala, India

Background and Objectives:

The morbidity and mortality spectrum of the south Indian state of Kerala is dominated by chronic non-communicable diseases, yet febrile illnesses because of neglected tropical diseases and emerging viral infections are often reported. As fever deaths are mostly avoidable, understanding the determinants of mortality is essential for implementing preventive measures.

Methods:

A case-control study was done during an ongoing dengue outbreak in Thiruvananthapuram district, Kerala during 2017–18. Cases included all fever deaths from the line list of Integrated Disease Surveillance Program (IDSP). Data were obtained from hospital case records and by interviewing patients or care givers. The theoretical model for determinants of mortality was constructed at three levels namely sociodemographic factors, access to health care and health seeking behavior, and clinical determinants.

Results:

This study confirmed association of mortality with age above 40 years (P = 0.010, OR = 3.48), being heavy built (P = 0.029, OR = 13.25), clinical symptoms of breathlessness (P < 0.001, OR = 24.89), restlessness (P < 0.001, OR = 97.26), clinical signs of drowsiness (P = 0.024, OR = 7.97), hypotension (P < 0.001, OR = 42.22), complications such as ARDS (P = 0.047, OR = 171.56), and myocarditis (P = 0.012, OR = 16.59). A low occupation status of semiskilled work or less (P = 0.012, OR = 0.30), choosing a nearby hospital for treatment (P = 0.018, OR = 0.48) and shortening the time gap between onset of symptom and final diagnosis (P = 0.044, OR = 0.72) was found to be protective.

Conclusion:

Along with biological and clinical factors, distal determinants like social factors, health seeking behavior, and health system factors are associated with fever mortality.

Assessing the risk of dengue severity using demographic information and laboratory test results with machine learning

BACKGROUND

Dengue virus causes a wide spectrum of disease, which ranges from subclinical disease to severe dengue shock syndrome. However, estimating the risk of severe outcomes using clinical presentation or laboratory test results for rapid patient triage remains a challenge. Here, we aimed to develop prognostic models for severe dengue using machine learning, according to demographic information and clinical laboratory data of patients with dengue.

METHODOLOGY/PRINCIPAL FINDINGS

Out of 1,581 patients in the National Cheng Kung University Hospital with suspected dengue infections and subjected to NS1 antigen, IgM and IgG, and qRT-PCR tests, 798 patients including 138 severe cases were enrolled in the study. The primary target outcome was severe dengue. Machine learning models were trained and tested using the patient dataset that included demographic information and qualitative laboratory test results collected on day 1 when they sought medical advice. To develop prognostic models, we applied various machine learning methods, including logistic regression, random forest, gradient boosting machine, support vector classifier, and artificial neural network, and compared the performance of the methods. The artificial neural network showed the highest average discrimination area under the receiver operating characteristic curve (0.8324 ± 0.0268) and balance accuracy (0.7523 ± 0.0273). According to the model explainer that analyzed the contributions/co-contributions of the different factors, patient age and dengue NS1 antigenemia were the two most important risk factors associated with severe dengue. Additionally, co-existence of anti-dengue IgM and IgG in patients with dengue increased the probability of severe dengue.

CONCLUSIONS/SIGNIFICANCE

We developed prognostic models for the prediction of dengue severity in patients, using machine learning. The discriminative ability of the artificial neural network exhibited good performance for severe dengue prognosis. This model could help clinicians obtain a rapid prognosis during dengue outbreaks. However, the model requires further validation using external cohorts in future studies.

Association of dengue disease severity and blood group: A systematic review and meta-analysis

Dengue disease encompasses various clinical manifestations including dengue fever (DF) and dengue hemorrhagic fever (DHF). In this article, we aimed to systematically review and analyze the association between different blood groups and severity of dengue. We searched nine databases for eligible papers reporting prevalence, distribution, and frequency of blood group type among dengue patients. Network meta-analysis using R software was used to analyze the data. Of a total of 63 reports screened, we included 10 studies with total sample size 1977 patients (1382 DF and 595 DHF). Blood group O was found to have the worst outcome with the highest risk of developing DF (P-score = 0.01) followed by group B (P-score = 0.34), group A (P-score = 0.64), and group AB (P-score = 1), respectively. Blood group O also had the worst outcome with highest risk of developing DHF (P-score = 0.1) followed by group B (P-score = 0.29), group A (P-score = 0.61), and group AB (P-score = 1), respectively. There was a significant increase (P-value <.001) in the overall odds risk of dengue infection among patients with Rhesus-positive blood groups [OR = 540.03; (95% CI = 151.48-1925.18)]. However, there was no significant difference in the odds risk of DF when compared to DHF according to Rhesus status (P-value = .954). This study identified the O blood group as a potential risk factor in predicting clinical severity in dengue patients which may be helpful in evaluating patients for their likely need for critical care.

Insect vectors endosymbionts as solutions against diseases

Viral diseases transmitted by mosquitoes, known as arboviruses, pose a significant threat to human life and are a major burden on many health systems around the world. Currently, arbovirus control strategies rely on insecticides or vector source reduction and, in the absence of effective, accessible and affordable vaccines, mainly on symptomatic based, non-specific treatments. However, insecticides have the potential to interfere with non-target organisms, cause environmental toxicity and insecticide resistance reduces their effectiveness as a sustainable control method. Complementary and sustainable strategies are urgently needed. Wolbachia, an invertebrate endosymbiont, has been used as an alternative strategy for arboviral control, through suppression or modification of mosquito populations. Here we discuss the burden that arboviruses impose on human populations and how Wolbachia can be used as a sustainable strategy for control, in alignment with the United Nations- 2030 Agenda for Sustainable Development.

Notified dengue deaths in Myanmar (2017-18): profile and diagnosis delays

Background: Complications in dengue usually occur between day four and day six after fever onset. Hence, early diagnosis and haematological monitoring are vital. Among all hospital reported dengue deaths in Myanmar in 2017-18, we assessed the i) patient profile, ii) proportion of patients who arrived with a dengue diagnosis at admission and iii) delays in diagnosis after fever onset.

Methods: This was a descriptive study involving secondary data. For all the notified deaths, death investigation forms were not available in prescribed format and therefore, data were extracted from hospital case records.

 Results: Of 304 deaths, 184 (60.5%) were female and 233 (76.6%) were less than 10 years old. Township level hospitals or below reported 36 deaths (11.8%) and the remaining deaths were from higher level facilities. Dengue was diagnosed before admission in 26 (8.5%) people and 169 (55.6%) were in shock at admission. Of 208 with date of fever onset recorded, the median diagnosis delay was four (interquartile range-IQR: 3, 5) days. Patient level delay (median three days) was a major contributor to the diagnosis delay.

Conclusions: Most of the patients who died did not have a diagnosis of dengue before admission. This calls for an urgent review of health system preparedness in peripheral health facilities to suspect, diagnose, monitor, refer and treat dengue in children and patient level factors for better understanding of the reasons of delay. Timely filling of death investigation forms in a prescribed format and quarterly death reviews based on these is recommended.

Dengue: A Minireview

Dengue, caused by infection of any of four dengue virus serotypes (DENV-1 to DENV-4), is a mosquito-borne disease of major public health concern associated with significant morbidity, mortality, and economic cost, particularly in developing countries. Dengue incidence has increased 30-fold in the last 50 years and over 50% of the world’s population, in more than 100 countries, live in areas at risk of DENV infection. We reviews DENV biology, epidemiology, transmission dynamics including circulating serotypes and genotypes, the immune response, the pathogenesis of the disease as well as updated diagnostic methods, treatments, vector control and vaccine developments.

Retrospective cross-sectional observational study on the epidemiological profile of dengue cases in Pernambuco state, Brazil, between 2015 and 2017

BACKGROUND

The spread of Dengue virus (DENV) infections, as well as their signs and symptoms, are the result of a complex interaction between several factors. In Brazil, especially in the Northeastern, dengue is an important public health problem. Here, we report an epidemiological analysis of dengue cases in Pernambuco state, Northeastern Brazil, during 2015-2017.

METHODS

This work is a retrospective cross-sectional observational study on the epidemiological profile of all dengue cases confirmed and reported to the Health Secretary of Pernambuco between 2015 and 2017. These data cover all municipalities of Pernambuco, except Fernando de Noronha. DENV-positive individuals were classified according to the dengue type (without and with warning signs, or severe dengue), age, gender, ethnicity and intermediate geographic region of residence (Recife, Caruaru, Serra Talhada or Petrolina). The distribution of cases over the years was assessed by χ2 test. Temperature and rainfall data were evaluated by Unpaired t-test. p-value < 0.05 and CI 95% were considered in all analyses.

RESULTS

Most dengue cases was without warning signs. The most observed characteristics in the less severe dengue phenotypes were: female, mulatto ethnicity and age between 20 and 39 years old; this profile was more clearly observed in 2015. In 2016 and 2017, however, the numbers of dengue without and with warning signs were more evenly distributed and the difference in cases within groups decreased significantly. Regarding severe dengue, mulattoes were the most affected, but it is possible to note a trend towards a more uniform distribution between the genders and ages. Recife was the region with the highest numbers of both total cases and incidence rates and the highest rainfall levels. Overall, over the years, there has been a decrease in dengue cases in all regions of Pernambuco.

CONCLUSIONS

We identified the epidemiological profile of dengue in Pernambuco, Brazil, reporting the gender, age, ethnicity and regions most affected by different dengue types. In addition, we observed that these cases were probably more influenced by rainfall than by temperature. Finally, we believe that this epidemiological knowledge is important to direct public health policies to the reality of each population.

Impact of Climate Variability and Abundance of Mosquitoes on Dengue Transmission in Central Vietnam

Dengue fever is an important arboviral disease in many countries. Its incidence has increased during the last decade in central Vietnam. Most dengue studies in Vietnam focused on the northern area (Hanoi) and southern regions but not on central Vietnam. Dengue transmission dynamics and relevant environmental risk factors in central Vietnam are not understood. This study aimed to evaluate spatiotemporal patterns of dengue fever in central Vietnam and effects of climatic factors and abundance of mosquitoes on its transmission. Dengue and mosquito surveillance data were obtained from the Department of Vector Control and Border Quarantine at Nha Trang Pasteur Institute. Geographic Information System and satellite remote sensing techniques were used to perform spatiotemporal analyses and to develop climate models using generalized additive models. During 2005-2018, 230,458 dengue cases were reported in central Vietnam. Da Nang and Khanh Hoa were two major hotspots in the study area. The final models indicated the important role of Indian Ocean Dipole, multivariate El Niño-Southern Oscillation index, and vector index in dengue transmission in both regions. Regional climatic variables and mosquito population may drive dengue transmission in central Vietnam. These findings provide important information for developing an early dengue warning system in central Vietnam.

Assessment of the long-term efficacy of a dengue vaccine against symptomatic, virologically-confirmed dengue disease by baseline dengue serostatus

CYD-TDV is a live, attenuated, tetravalent dengue vaccine licensed in 21 countries. We undertook a post-hoc analysis of the long-term efficacy of CYD-TDV during the surveillance expansion phase (SEP) of two Phase III studies (CYD14 in the Asia-Pacific region; CYD15 in Latin America). The SEP included approximately Year 5 and the entire Year 6 of follow-up after the first study injection. Vaccine efficacy against symptomatic virologically-confirmed dengue (VCD) was assessed by participant age (any age, ≥9, <9, 2-5, and 6-8 years at the time of the first injection) and baseline dengue serostatus using a case-cohort framework. Baseline dengue serostatus was estimated by several methods including logistic regression-based multiple imputation (MI) to predict PRNT₅₀ with key predictor being Month 13 (M13) anti-non-structural protein (NS1) titers; superlearner-based imputation by targeted minimum loss based estimation (TMLE); and M13 anti-NS1 titer threshold 9 EU/mL (NS1 M13). There were 436 symptomatic VCD cases (CYD14: n = 360; CYD15: n = 76) during the SEP. Vaccine efficacy in seropositive participants aged ≥9 years was assessed by MI (47.9% [95% CI 19.4; 66.3]), TMLE (53.0% [95% CI 23; 71]), and NS1 M13 (52.4% [95% CI 30.8; 67.3]). Vaccine efficacy estimates were lower in seropositive individuals aged <9 years compared with individuals ≥9 years. Among seropositive individuals aged 2-5 and 6-8 years, vaccine efficacy across the different approaches for assessing serostatus ranged from between -25.7 to 36.9% and 44.4 to 64.7% during the SEP, respectively. In the pooled CYD14/15 data of seronegatives, vaccine efficacy was null to modest. In conclusion, CYD-TDV was shown to maintain efficacy against symptomatic VCD in seropositive participants aged ≥9 years up to six years after the first dose. Persistence of efficacy was also observed in seropositive participants aged 6-8 years.

Non-structural protein 1 (NS1) of dengue virus detection correlates with severity in primary but not in secondary dengue infection

BACKGROUND

Non-structural protein 1 (NS1) of dengue virus circulates in the serum of patients during the acute phase of the disease.

OBJECTIVES

To determine whether NS1 screening can serve in diagnosing primary and secondary infection and to evaluate its utility as a marker for predicting the severity of dengue in children.

STUDY DESIGN

Patients ≤15 years of age hospitalized for dengue between 2012-2018, with NS1 determination (Panbio, Australia) were included. Clinical y laboratorial characteristics were collected in a standardized data table for analysis of correlation between serotypes, primary or secondary condition of infection, severity, and presence of NS1.

RESULTS

Of 709 children hospitalized for dengue with NS1 determination, 479 (67.5 %) had the positive test. Of the 378 primary cases, 320 (85 %) were NS1 (+). while among the 242 secondary cases only 103 (42.5 %) were NS1 (+) (p < 0001). Of the 479 patients with NS1 (+), 344 (72 %) were warnig-signed cases (WSC) and 94 (19 %) were severe cases (SC), being these figures 62 % and 34 %, in the NS1 negative patients respectively (p < 0.001). There was no difference in the frequency of WSC or SC between patients with NS1 positive or negative test in secondary dengue; however, in primary dengue, the figures were 68 % vs 32 % (p < 0.001), and 87 % vs 12 % (p < 0.001), respectively.

CONCLUSIONS

The presence of NS1 positive test is associated with the condition of infection (primary or secondary) and exhibited an increased risk of developing forms with warning signs or severe dengue in primary cases, but not in secondary cases.

Severe dengue categories as research endpoints-Results from a prospective observational study in hospitalised dengue patients

Severe dengue was perceived as one clinical disease entity until the WHO 2009 classification stratified it into severe vascular leakage, severe bleeding, and severe organ dysfunction. The objectives of this study were to investigate the potential use of severe dengue categories as endpoints for intervention research. 271 patients with severe dengue among 1734 confirmed dengue patients were followed prospectively in this hospital-based observational study in Latin America and Asia. We compared the distribution of severe dengue categories according to gender and age (below/above 15y), and determined the relative frequency and the overlap of severe dengue categories in the same patients. In a next step, we extended the analysis to candidate moderate severity categories, based on recently suggested definitions which were adapted for our purposes. Severe vascular leakage occurred in 244 (90%), severe bleeding in 39 (14%), and severe organ dysfunction in 28 (10%) of 271 severe dengue patients. A higher frequency of severe leakage was seen in children or adolescents (<15y) compared to adults. More than 80% of the severe leakage cases, and 30-50% of the cases with severe bleeding or severe organ dysfunction, were defined as severe on the basis of that feature alone. In 136 out of 213 patients with severe leakage alone, neither moderate bleeding manifestation nor hepatic involvement was recorded. On the other hand, moderate leakage manifestations were detected in 4 out of 12 cases that were classified as severe based on bleeding alone. A major proportion of severe dengue patients exhibited clinical manifestations of severe vascular leakage only, which may constitute a useful endpoint for intervention research or pathophysiology studies. Severe bleeding and severe organ manifestation were recorded less frequently and exhibited a higher degree of overlap with severe leakage. Severe bleeding without leakage may be associated with individual predisposition or the presence of comorbidities. More detailed assessments are needed to explore this hypothesis. Candidate moderate disease endpoints were investigated and need to be further validated.

Association of Allergic Symptoms with Dengue Infection and Severity: A Systematic Review and Meta-analysis

The relationship between the severity of dengue infection and allergy is still obscure. We conducted an electronic search across 12 databases for relevant articles reporting allergic symptoms, dengue infection, and dengue classification. These studies were categorized according to dengue severity and allergy symptoms, and a meta-analysis was performed by pooling the studies in each category. Among the included 57 articles, pruritus was the most common allergic sign followed by non-specified allergy and asthma (28.6%, 13%, and 6.5%, respectively). Despite the reported significant association of dengue with pruritus and total IgE level (P < 0.05), in comparison with non-dengue cases and healthy controls, there was no association between the different severe dengue group with pruritus, skin allergy, food allergy or asthma. However, removing the largest study revealed a significant association between asthma with dengue hemorrhagic fever (DHF) rather than dengue fever (DF). In comparison with DF, DHF was associated with IgE positivity. Furthermore, specific-IgE level was higher in secondary DF rather than primary DF. There was a possible association between allergy symptoms and dengue severity progression. Further studies are needed to clarify this association.

Dengue Virus

Dengue virus (DENV) belongs to the family Flaviviridae, genus Flavivirus. It is a single-stranded positive-sense ribonucleic acid virus with 10,700 bases. The genus Flavivirus includes other arthropod borne viruses such as yellow fever virus, West Nile virus, Zika virus, tick-borne encephalitis virus. It infects ~50–200 million people annually, putting over 3.6 billion people living in tropical regions at risk and causing ~20,000 deaths annually. The expansion of dengue is attributed to factors such as the modern dynamics of climate change, globalization, travel, trade, socioeconomics, settlement, and also viral evolution. There are four antigenically different serotypes of DENV based on the differences in their viral structural and nonstructural proteins. DENV infection causes a spectrum of illness ranging from asymptomatic to dengue fever to severe dengue shock syndrome. Infection with one serotype confers lifelong immunity against that serotype, but heterologus infection leads to severe dengue hemorrhagic fever due to antibody-dependent enhancement. Diagnosis of dengue infections is based mainly on serological detection of either antigen in acute cases or antibodies in both acute and chronic infection. Viral detection and real-time PCR detection though helpful is not feasible in resource poor setup. Treatment of dengue depends on symptomatic management along with fluid resuscitation and may require platelet transfusion. Although vaccine development is in late stages of development, developing a single vaccine against four serotypes often causes serious challenges to researchers; hence, the main stay of prevention is vector control and management.