Prognostic values of serum lactate-to-bicarbonate ratio and lactate for predicting 28-day in-hospital mortality in children with dengue shock syndrome

This study aimed to assess the clinical utility of blood lactate-to-bicarbonate (L/B) ratio, as a prognostic factor for 28-day in-hospital mortality in children with dengue shock syndrome (DSS), admitted to the pediatric intensive care unit (PICU). This single-center retrospective study was conducted at a tertiary children hospital in southern Vietnam from 2013 to mid-2022. Prognostic models for DSS mortality were developed, using a predefined set of covariates in the first 24 hours of PICU admission. Area under the curves (AUCs), multivariable logistic and Least Absolute Shrinkage and Selection Operator (LASSO) regressions, bootstrapping and calibration slope were performed. A total of 492 children with DSS and complete clinical and biomarker data were included in the analysis, and 26 (5.3%) patients died. The predictive values for DSS mortality, regarding lactate showing AUC 0.876 (95% CI, 0.807-0.944), and that of L/B ratio 0.867 (95% CI, 0.80-0.934) (P values of both biomarkers < .001). The optimal cutoff point of the L/B ratio was 0.25, while that of lactate was 4.2 mmol/L. The multivariable model showed significant clinical predictors of DSS fatality including severe bleeding, cumulative amount of fluid infused and vasoactive-inotropic score (>30) in the first 24 hours of PICU admission. Combined with the identified clinical predictors, the L/B ratio yielded higher prognostic values (odds ratio [OR] = 8.66, 95% confidence interval [CI], 1.96-38.3; P < .01) than the lactate-based model (OR = 1.35, 95% CI, 1.15-1.58; P < .001). Both the L/B and lactate models showed similarly good performances. Considering that the L/B ratio has a better prognostic value than the lactate model, it may be considered a potential prognostic biomarker in clinical use for predicting 28-day mortality in PICU-admitted children with DSS.

Pediatric Profound Dengue Shock Syndrome and Use of Point-of-Care Ultrasound During Mechanical Ventilation to Guide Treatment: Single-Center Retrospective Study, 2013-2021

OBJECTIVES

Profound dengue shock syndrome (DSS) complicated by severe respiratory failure necessitating mechanical ventilation (MV) accounts for high case fatality rates among PICU-admitted patients. A major challenge to management is the assessment of intravascular volume, which can be hampered by severe plasma leakage and the use of MV.

DESIGN

Retrospective cohort, from 2013 to 2021.

PATIENTS

Sixty-seven children with profound DSS supported by MV, some of whom underwent bedside point-of-care ultrasound (POCUS) for assessment and monitoring of hemodynamics and fluid administration.

SETTING

PICU of the tertiary Children's Hospital No. 2 in Vietnam.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We analyzed data clinical and laboratory data during PICU stay. In particular, during use of MV (i.e., at times 0-, 6-, and 24-hr after commencement) and fluid resuscitation. The primary study outcome was 28-day in-hospital mortality, and the secondary outcomes were associations with changes in hemodynamics, blood lactate, and vasoactive-inotrope score (VIS). Patients had a median age of 7 years (interquartile range, 4-9). Use of POCUS during fluid management (39/67), as opposed to not using (28/67), was associated with lower mortality (6/39 [15%] vs. 18/28 [64%]; difference 49 % [95% CI, 28-70%], p < 0.001). Use of POCUS was associated with lower odds of death (adjusted odds ratio 0.17 [95% CI, 0.04-0.76], p = 0.02). The utilization of POCUS, versus not, was associated with greater use of resuscitation fluid, and reductions in VIS and pediatric logistic organ dysfunction (PELOD-2) score at 24 hours after MV and PICU discharge.

CONCLUSIONS

In our experience of pediatric patients with profound DSS and undergoing MV (2013-2021), POCUS use was associated with lower odds of death, a higher volume of resuscitation fluid, and improvements in the blood lactate levels, VIS, and PELOD-2 score.

Neurological Complications in Dengue Among Males of the Adult Age Group

Neurological problems are more frequently linked to dengue, a mosquito-transmitted virus common in tropical areas. This review study thoroughly examines the effects of dengue on adult males' neurological systems. Dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) can develop in severe cases of dengue fever caused by the dengue virus (DENV). Unsettlingly, it is thought that a sizable portion of DENV infections impact the central nervous system (CNS), which calls into question the former theory that the DENV is not neurotropic. This review dissects the many neurological manifestations of dengue, spanning from encephalopathy, encephalitis, and other CNS implications to peripheral neuromuscular issues, through the systematic analysis of publications gathered from PubMed. The essay emphasizes the immunological reactions brought on by DENV infections and offers a deeper understanding of the pathophysiology. Given that they exhibit similar first symptoms, Zika and chikungunya are two more illnesses that must be distinguished from dengue. The mainstay of current diagnostic methods is serum and cerebrospinal fluid (CSF) tests, although supportive care is still used. This review highlights the importance of tracking neurological symptoms in dengue patients and encourages more studies in this area.

Updates in the Management of Dengue Shock Syndrome: A Comprehensive Review

Dengue is a very serious public health problem that can manifest a wide range of symptoms from asymptomatic to fatal conditions, such as dengue shock syndrome (DSS). It is a life-threatening mosquito-borne viral infection widely spread in tropical areas. Dengue virus transmission occurs from an infected Aedes mosquito to humans. Various factors are responsible for the occurrence of the disease, such as viral load, age of the host, immune status of the host, and genetic variability. Dengue infection occurs in three phases: febrile, critical, and recovery. The febrile phase lasts for seven days and manifests symptoms such as high-grade fever, headache, arthralgia, and backache, and in some cases, the upper respiratory tract and gastrointestinal tract are also involved. Severe dengue is characterized by endothelial dysfunction that causes vascular permeability and plasma leakage. The fundamental mechanisms of these immune pathologies are not yet known. Dengue manifests various complications such as dengue encephalopathy, encephalitis, stroke, ocular involvement, acute transverse myelitis, myalgia, and cerebellar syndrome, but the most commonly seen is liver involvement. Dengue is managed supportively because there are no proven curative treatments. The cornerstone of care during the critical period of dengue is prudent fluid resuscitation. The first fluid of preference is a crystalloid. Prophylactic transfusion of platelets is not advised. The occurrence of four antigenically different dengue virus serotypes, each able to elicit a cross-reactive and disease-enhancing antibody response against the other three serotypes, has made the creation of the dengue vaccine a difficult undertaking. The development of a dengue vaccine has faced significant challenges due to a lack of the best animal models and a variety of immunological conditions in people, particularly in endemic locations. Dengvaxia is a live attenuated vaccine, which was developed by Sanofi. It is made up of four chimeric vaccine viruses produced by Vero cells.

Acute liver failure in a young patient with dengue shock syndrome: a case report

Dengue fever is caused by dengue virus, which has four different serotypes and is transmitted by the Aedes mosquitos. This disease is endemic to Southeast Asian countries, including Nepal. Liver involvement in dengue is a crucial feature, and the effect ranges from an asymptomatic rise in liver enzymes to the development of acute liver failure. Acute liver failure often results in multiorgan dysfunction including hemodynamic instability, renal failure, cerebral edema, and even death because of shock. Prompt diagnosis and management are necessary to prevent complications. However, there is no proven proper treatment for this condition, and the only treatment modality is to prevent the symptoms. We presented the case of a young female with dengue fever who developed a life-threatening acute liver failure because of dengue shock syndrome.

Vitamin D Deficiency (VDD) and Susceptibility towards Severe Dengue Fever-A Prospective Cross-Sectional Study of Hospitalized Dengue Fever Patients from Lahore, Pakistan

Dengue is a mosquito-borne flaviviral serious febrile illness, most common in the tropical and subtropical regions including Pakistan. Vitamin D is a strong immunomodulator affecting both the innate and adaptive immune responses and plays a pivotal role in pathogen-defense mechanisms. There has been considerable interest in the possible role of vitamin D in dengue viral (DENV) infection. In the present prospective cross-sectional study, we assessed a possible association between serum vitamin D deficiency (VDD) and susceptibility towards severe dengue fever (DF) illness. Serum vitamin D levels were measured at the time of hospitalization in 97 patients diagnosed with dengue fever (DF), dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) at Mayo Hospital, King Edward Medical University, Lahore, PK, from 16 November 2021 to 15 January 2022. In terms of disease severity, 37 (38.1%) patients were DF, 52 (53.6%) were DHF grade 1 and 2, and 8 (8.2%) were DSS. The results revealed that most patients (75 (77.3%)) were vitamin-D-deficient (i.e., serum level < 20 ng/mL), including 27 (73.0%) in DF, 41 (78.8%) in DHF grade 1 and 2, and 7 (87.5%) in DSS. The degree of VDD was somewhat higher in DSS patients as compared to DF and DHF grade 1 and 2 patients. Overall, serum vitamin D levels ranged from 4.2 to 109.7 ng/mL, and the median (IQR) was in the VDD range, i.e., 12.2 (9.1, 17.8) ng/mL. Our results suggest that there may be a possible association between VDD and susceptibility towards severe dengue illness. Hence, maintaining sufficient vitamin D levels in the body either through diet or supplementation may help provide adequate immune protection against severe dengue fever illness. Further research is warranted.

The Serological Confirmation and Outcome of the Pediatric Dengue Patients Presenting to Emergency Department: A Cross-Sectional Study

Background

In the emergency department, it is very uncommon perform a differential diagnosis to serologically differentiate between dengue, dengue hemorrhagic fever, and dengue shock syndrome. Prompt differential diagnosis and treatment is essential with the presentation of dengue. This study aims to determine the serological confirmation and outcome of the dengue epidemic in the pediatric population presenting to the ED in a tertiary care hospital.

Methods

A single-center cross-sectional study was conducted. All pediatric patients aged less than 18 years presented to ED with clinical features suggestive of DF, DFF, and DSS while also doing the serological confirmation for the dengue were enrolled in the study. Data was collected on demographics, clinical characteristics, diagnosis, and outcomes of 324 pediatric patients. Multivariable binary logistic regression was applied for the analysis.

Results

Out of 324 patients, 191 (59.13%) underwent NS1 testing and 132 (40.87%) did the IgM test. Most participants were in the age range of 13 to 18 years in both groups. Fever was the most common complaint in both groups 191 (100%) and 132 (100%). In each group, around one-third of the participants complained about body aches 69 (36.13%) and 44 (33.33%). The patient having a history of traveling within the past 14 days created a 1.51 (95% CI: 1.27-2.25) times higher odds of contracting dengue fever as compared to no history of travel.

Conclusion

The serologic confirmation of dengue in the ED helps in both the adequate and timely treatment as well as patient disposition and ultimately saves lives.

Association of dengue virus non-structural-1 protein with disease severity: a brief review

Dengue virus (DENV) was discovered by P. M. Ashburn and Charles F. Craig in 1907. Evidence of dengue-like illness was observed before 1907 and DENV epidemics have been reported from different parts of the world since then, with increased morbidity rates every year. DENV typically causes a febrile illness that ranges from mild asymptomatic infection to fatal dengue haemorrhagic fever (DHF) and/or dengue shock syndrome (DSS). Host mechanisms through which mild infection progresses to the fatal forms are still unknown. Few factors have been associated to aid severe disease acquisition, DENV non-structural 1 (NS1) protein being one of them. NS1 is a highly conserved glycoprotein among the Flavivirus and is often used as a biomarker for dengue diagnosis. This review focuses on assessing the role of NS1 in severe dengue. In this review, hospital-based studies on the association of dengue NS1 with severe dengue from all over the world have been assessed and analysed and the majority of the studies positively correlate high NS1 levels with DHF/DSS acquisition. The review also discusses a few experimental studies on NS1 that have shown it contributes to dengue pathogenesis. This review assesses the role of NS1 and disease severity from hospital-based studies and aims to provide better insights on the kinetics and dynamics of DENV infection with respect to NS1 for a better understanding of the role of NS1 in dengue.

Prognostic Indicators for the Early Prediction of Severe Dengue Infection: A Retrospective Study in a University Hospital in Thailand

This study aimed to develop simple diagnostic guidelines which would be useful for the early detection of severe dengue infections. Retrospective data of patients with dengue infection were reviewed. Patients with diagnosed dengue infection were categorized in line with the International Statistical Classification of Diseases (ICD-10): A90, dengue fever; A91, dengue hemorrhagic fever; and A910, dengue hemorrhagic fever with shock. A total of 302 dengue-infected patients were enrolled, of which 136 (45%) were male and 166 (55%) were female. Multivariate analysis was conducted to determine independent diagnostic predictors of severe dengue infection and to convert simple diagnostic guidelines into a scoring system for disease severity. Coefficients for significant predictors of disease severity generated by ordinal multivariable logistic regression analysis were transformed into item scores. The derived total scores ranged from 0 to 38.6. The cut-off score for predicting dengue severity was higher than 14, with an area under the receiver operating curve (AUROC) of 0.902. The predicted positive value (PPV) was 68.7% and the negative predictive value (NPV) was 94.1%. Our study demonstrates that several diagnostic parameters can be effectively combined into a simple score sheet with predictive value for the severity evaluation of dengue infection.

Cardiovascular sequelae of dengue fever: a systematic review

BACKGROUND

: Dengue is the most important viral diseases globally and a majority of symptomatic infections result in a benign course. However, a small number of patients develop severe manifestations, including myocardial impairment, arrhythmias, and fulminant myocarditis.

AREAS COVERED

This review outlines the incidence of cardiovascular (CV) manifestations of dengue. Electronic databases, including PubMed/MEDLINE, EMBASE, Scopus, and CINAHL were searched for articles incorporating cardiac manifestations of dengue fever (DF).

EXPERT OPINION

: Included studies involved 6,773 patients and 3,122 (46.1%) exhibited at least one cardiac manifestation with DF. Electrocardiogram (ECG) abnormalities (30.6%) included sinus bradycardia (8.8%), non-specific ST-T changes (8.6%), ST depression (7.9%), and T-wave inversion (2.3%). Mechanical sequelae were present in 10.4%, including left ventricular (LV) systolic dysfunction (5.7%), and myocarditis (2.9%). Pericardial involvement was noted as pericarditis (0.1%), pericardial effusion (1.3%), and pericardial tamponade (0.1%). Apart from that, the cardiac injury was depicted through a rise in cardiac enzymes (4.5%). The spectrum of CV manifestations in dengue is broad, ranging from subtle ST-T changes to fulminant myocarditis. This can be a cause of hemodynamic collapse during the critical phase of capillary leakage. Use of contemporary techniques in diagnosing cardiac involvement should be employed for rapid diagnosis and treatment in DF.

Presenting Complaints in Acute Dengue Infection and Differences in Presenting Complaints Between Primary and Secondary Dengue Infections

Aim and objectives

To describe the presenting complaints in acute dengue infection, and identify any differences in presenting complaints between primary and secondary dengue infection patients.

Material and methods

This cross-sectional observational study was conducted at the Department of Infectious Diseases and Medicine, Holy Family Hospital, Rawalpindi, from July 2019 to December 2019 during the Dengue Rawalpindi Epidemic 2019. Presenting complaints of patients who fulfilled the inclusion criteria of the study were recorded on a proforma on their admissions and their informed consent was taken. Of these patients, 70 primary and 70 secondary dengue infection patients were randomly selected for comparison of presenting complaints. The two groups were compared using the chi-square test and a P-value of <0.05 was considered significant.

Results

Intermittent fever (88.6%), headache (85%), myalgia (87.9%), arthralgia/bone pain (75%), and retro-orbital pain (47.9%) were common in most dengue patients. Hemorrhagic manifestations, such as rash (15%), epistaxis (11.4%), gum bleeding (15%), melena (7.9%), hematemesis (6.4%), hemoptysis (5.7%), and hematuria (6.4%), were less common.

Abdominal pain was significantly more common in secondary dengue infections (50% in secondary dengue infections compared to 32.9% in primary dengue infections).

Conclusions

Fever, headache, myalgia, arthralgia/bone pains, retro-orbital pain as well as rash, epistaxis, gum bleeding, melena, hematemesis, hemoptysis, hematuria, and decreased urine output despite fluid intake are presenting complaints of dengue infection.

Patients with abdominal pain in addition to the above presenting complaints are more likely to be cases of the more serious secondary dengue infection. 

Dengue and the Lectin Pathway of the Complement System

Dengue is a mosquito-borne viral disease causing significant health and economic burdens globally. The dengue virus (DENV) comprises four serotypes (DENV1-4). Usually, the primary infection is asymptomatic or causes mild dengue fever (DF), while secondary infections with a different serotype increase the risk of severe dengue disease (dengue hemorrhagic fever, DHF). Complement system activation induces inflammation and tissue injury, contributing to disease pathogenesis. However, in asymptomatic or primary infections, protective immunity largely results from the complement system’s lectin pathway (LP), which is activated through foreign glycan recognition. Differences in N-glycans displayed on the DENV envelope membrane influence the lectin pattern recognition receptor (PRR) binding efficiency. The important PRR, mannan binding lectin (MBL), mediates DENV neutralization through (1) a complement activation-independent mechanism via direct MBL glycan recognition, thereby inhibiting DENV attachment to host target cells, or (2) a complement activation-dependent mechanism following the attachment of complement opsonins C3b and C4b to virion surfaces. The serum concentrations of lectin PRRs and their polymorphisms influence these LP activities. Conversely, to escape the LP attack and enhance the infectivity, DENV utilizes the secreted form of nonstructural protein 1 (sNS1) to counteract the MBL effects, thereby increasing viral survival and dissemination.

A Fatal Case of Dengue-Associated Hemophagocytic Lymphohistiocytosis and Retroperitoneal Hematoma in a Patient With Autoimmune Hemolytic Anemia

Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially life-threatening complication of dengue infection which necessitates early diagnosis and treatment to improve patient outcomes. Severe dengue infection complicated by HLH may require interventions such as systemic corticosteroids, intravenous immunoglobulin, or chemotherapy. Here, we report a case of concurrent dengue-induced HLH and flare of underlying autoimmune hemolytic anemia (AIHA). The disease was refractory to treatment including corticosteroids and intravenous immunoglobulin. The course of illness was later complicated by dengue shock syndrome, severe liver dysfunction, and a large retroperitoneal hematoma. Unfortunately, the patient succumbed on day 10 of illness.

Matrix metalloproteinases in the pathogenesis of dengue viral disease: Involvement of immune system and newer therapeutic strategies

Globally, the burden due to dengue infection is increasing with a recent estimate of 96 million progressing to the disease every year. Dengue pathogenesis and the factors influencing it are not completely known. It is now widely speculated that there is an important role of matrix metalloproteinases (MMPs) in the initiation and progression of dengue pathogenesis; however, their exact roles are not fully understood. Overactivation of matrix metalloproteinases may contribute to the severity of dengue pathogenesis. Cytokines and various other mediators of inflammation interact with the vascular endothelium and matrix metalloproteinases may be one of the components among them. Extensive plasma leakage into tissue spaces may result in a shock. It is evident in the literature that MMP2 and MMP9 increase in dengue patients is correlated with the severity of the disease; however, the underlying mechanism is still unknown. Activation of innate cells and adaptive immune cells which include, B and T cells, macrophages or monocytes and dendritic cells also contribute to the dengue pathology. Newer therapeutic strategies include microRNAs, such as miR-134 (targets MMP3 and MMP1) and MicroRNA-320d, (targets MMP/TIMP proteolytic system). The use of antibodies-based therapeutics like (Andecaliximab; anti-matrix metalloproteinase-9 antibody) is also suggested against MMPs in dengue. In this review, we summarize some recent developments associated with the involvement of immune cells and their mediators associated with the matrix metalloproteinases mediated dengue pathogenesis. We highlight that, there is still very little knowledge about the MMPs in dengue pathogenesis which needs attention and extensive investigations.

Microvascular Fluid Exchange: Implications of the Revised Starling Model for Resuscitation of Dengue Shock Syndrome

Dengue is the most common mosquito-borne viral infection in the world. The most feared complication is a poorly understood vasculopathy that occurs in only a small minority of symptomatic individuals, especially children and young adults, but can result in potentially fatal dengue shock syndrome (DSS). Based mainly on expert opinion, WHO management guidelines for DSS recommend prompt infusion of a crystalloid fluid bolus followed by a tapering crystalloid fluid regimen, supplemented if necessary by boluses of synthetic colloid solutions. However, following publication of a number of major trials undertaken in other, primarily adult, critical care scenarios, use of both synthetic colloid solutions and of fluid boluses for volume expansion have become controversial. Synthetic colloids tend to be used for severe DSS cases in order to boost intravascular oncotic pressure, based on the classic Starling hypothesis in which opposing hydrostatic and oncotic forces determine fluid flow across the microvascular barrier. However, the revised Starling model emphasizes the critical contribution of the endothelial glycocalyx layer (EGL), indicating that it is the effective oncotic pressure gradient across the EGL not endothelial cells per se that opposes filtration. Based on several novel concepts that are integral to the revised Starling model, we review the clinical features of DSS and discuss a number of implications that are relevant for fluid management. We also highlight the need for context-specific clinical trials that address crucially important questions around the management of DSS.

Dengue Fever in the Darfur Area, Western Sudan

We report an outbreak of dengue in Darfur, western Sudan, during September 2014–April 2015. Dengue virus–specific PCR testing of 50 samples from nonmalaria febrile illness case-patients confirmed 35 dengue cases. We detected 7 cases of dengue shock syndrome and 24 cases of dengue hemorrhagic fever.

Clinical prognostic models for severe dengue: a systematic review protocol

Background: Dengue is a common mosquito-borne, with high morbidity rates recorded in the annual. Dengue contributes to a major disease burden in many tropical countries. This demonstrates the urgent need in developing effective approaches to identify severe cases early. For this purpose, many multivariable prognostic models using multiple prognostic variables were developed to predict the risk of progression to severe outcomes. The aim of the planned systematic review is to identify and describe the existing clinical multivariable prognostic models for severe dengue as well as examine the possibility of combining them. These findings will suggest directions for further research of this field. Methods: This protocol has followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta - Analyses Protocol (PRISMA-P). We will conduct a comprehensive search of Pubmed, Embase, and Web of Science. Eligibility criteria include being published in peer-review journals, focusing on human subjects and developing the multivariable prognostic model for severe dengue, without any restriction on language, location and period of publication, and study design. The reference list will be captured and removed from duplications. We will use the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS) checklist to extract data and Prediction study risk of bias assessment tool (PROBAST) to assess the study quality. Discussion: This systematic review will describe the existing prediction models, summarize the current status of prognostic research on dengue, and report the possibility to combine the models to optimize the power of each paradigm. PROSPERO registration: CRD42018102907.

Clinical prognostic models for severe dengue: a systematic review protocol

Background: Dengue is a common mosquito-borne, with high morbidity rates recorded in the annually. Dengue contributes a major disease burden in many tropical countries. This demonstrates the urgent need in developing effective approaches to identify severe cases early. For this purpose, many multivariable prognostic models using multiple prognostic variables were developed to predict the risk of progression to severe outcomes. The aim of the planned systematic review is to identify and describe the existing clinical multivariable prognostic models for severe dengue as well as examine the possibility of combining them. These findings will suggest directions for further research of this field. Methods: This protocol has followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta - Analyses Protocol (PRISMA-P). We will conduct a comprehensive search of Pubmed, Embase and Web of Science. Eligiblity criteria include being published in peer-review journals, focusing on human subjects and developing the multivariable prognostic model for severe dengue, without any restriction on language, location and period of publication, and study design. The reference list will be captured and removed from duplications. We will use the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS) checklist to extract data and Prediction study risk of bias assessment tool (PROBAST) to assess the study quality. Discussion: This systematic review will describe the existing prediction models, summarize the current status of prognostic research on dengue, and report the possibility to combine the models to optimize the power of each paradigm. PROSPERO registration: CRD42018102907.

Need for guidelines for the combined management of pregnancy and dengue: a retrospective study from an Indian tertiary care maternity hospital

The incidence of dengue has risen in India in recent years. Evidence suggests that dengue in pregnancy may be associated with adverse maternal and fetal outcomes. The aim of our study was to analyse outcomes in pregnant women with confirmed dengue infection who had the benefit of close monitoring and intensive management at a tertiary maternity facility. We reviewed hospital data of 44 (0.11%) such women at Fernandez Hospital, a tertiary maternity unit, during the five-year period from 2011 to 2016. Maternal and fetal variables were collected from case sheets. Dengue haemorrhagic fever was seen in 15.9% and dengue shock syndrome in one fatal case (2.2%). Thrombocytopenia was seen in 31 cases (70.4%) and 14 (31.81%) received platelets transfusions. Fetal outcomes in our series were favourable, except for one stillbirth, with 45.4% preterm deliveries and 15.9% small for gestational age babies. Dengue in pregnancy is definitely associated with maternal and fetal morbidity and mortality. A high index of suspicion of dengue is required in pregnant women with pyrexia and thrombocytopenia.

Host Genetic Polymorphisms Influencing Susceptibility to Dengue

Dengue is a pandemic-prone viral disease which is endemic in more than 100 countries and which puts half of the world's population at risk. While the disease presents as subclinical infection or mild fever in the majority of cases, approximately a quarter of the infected individuals experience severe forms of disease like dengue hemorrhagic fever/dengue shock syndrome that cause significant rates of mortality and morbidity. The pathogenesis of this differential outcome of infection is determined by a complex interplay of factors associated with the virus, vector, and host; much of which is not completely understood. In this review, we present an update on the various host genetic polymorphisms that have been reported to influence the susceptibility to dengue. For the convenience of discussion, we have categorized the genetic factors according to the different arms of the immune system with which the corresponding immune determinants are associated.

Cloning and Expression of NS3 Gene of Pakistani Isolate Type 2 Dengue Virus

Introduction

Dengue is one of the major emerging viral diseases in the world, with dramatic increases in reported cases in the last few decades and annual worldwide occurrence of approximately 390 million infections. It is a highly important mosquito-vectored disease and is a problem in tropical and subtropical areas of the world. The major aim of this study was to clone and express the dengue NS3 gene, in service to its therapeutic importance for the development of stable cell lines.

Material and Methods

Blood samples from dengue fever (DF) patients were collected and subjected to PCR amplification of the NS3 gene of dengue virus serotype-2 (DENV-2). The NS3 gene was amplified using gene specific primers and cloned in the TA cloning vectors.

Results

The gene was successfully expressed in mammalian expression vector pcDNA3.1. The current finding was different from a previously reported DENV-2 strain replicon constructed in different cells, in which the whole genetic material of the virus was used instead of an active protease gene, and which gave a low yield of replicon expressing cells.

Conclusion

Recombinant NS3 could be used to produce an antibody that is possibly helpful for developing a single step diagnostic assay to detect the dengue virus NS3 antigen in sera of dengue patients.

Acute Renal Failure Adversely Affects Survival in Pediatric Dengue Infection

Aims

Dengue is currently one of the most important mosquito-borne viral infections. Acute renal failure (ARF) is a serious complication among children suffering from dengue infection.

Subjects and Methods

A retrospective cohort review of baseline characteristics, disease outcomes, and risk factors of dengue-infected patients, with and without renal failure (RF), were compared.

Results

Among 97 children with dengue, 13.4% had RF (estimated glomerular filtration rate <60 ml/min/1.73 m²) at presentation. In comparison to all children (100%) of RF cohort, only 32% children of non-RF cohort (P < 0.0001) were suffering either from dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). The 7-day survival rate was 61.5% (8/13) among RF group as compared to 96.4% (81/84) in non-RF group (P < 0.001). When a fraction of patients who needed vasopressor support were significantly higher in RF cohort (70% vs. 14% for RF and non-RF, respectively, P < 0.001), requirement of mechanical ventilation (15% vs. 11%, P = 0.67) was comparable in both cohorts.

Conclusions

DHF/DSS is an independent risk factor for the development of ARF in patients with dengue infection. Mortality rate is high once RF develops in these children.

Clinical Efficacy, Safety, and Immunogenicity of a Live Attenuated Tetravalent Dengue Vaccine (CYD-TDV) in Children: A Systematic Review with Meta-analysis

BACKGROUND

Dengue hemorrhagic fever is the leading cause of hospitalization and death in children living in Asia and Latin America. There is an urgent need for an effective and safe dengue vaccine to reduce morbidity and mortality in this high-risk population given the lack of dengue specific treatment at present. This review aims to determine the efficacy, safety, and immunogenicity of CYD-TDV vaccine in children.

METHODS

This is a systematic review including meta-analysis of randomized controlled clinical trial data from Embase, Medline, the Cochrane Library, Web of Science, and ClinicalTrials.gov. Studies that assessed CYD-TDV vaccine efficacy [(1 - RR)*100], safety (RR), and immunogenicity (weighted mean difference) in children were included in this study. Random effects model was employed to analyze patient-level data extracted from primary studies.

RESULTS

The overall efficacy of CYD-TDV vaccine was 54% (40-64), while serotype-specific efficacy was 77% (66-85) for DENV4, 75% (65-82) for DENV3, 50% (36-61) for DENV1, and 34% (14-49) for DENV2. 15% (-174-74) vaccine efficacy was obtained for the unknown serotype. Meta-analysis of included studies with longer follow-up time (25 months) revealed that CYD-TDV vaccine significantly increased the risk of injection site reactions (RR = 1.1: 1.04-1.17; p-value = 0.001). Immunogenicity (expressed as geometric mean titers) in descending order was 439.7 (331.7-547.7), 323 (247 - 398.7), 144.1 (117.9-170.2), and 105 (88.7-122.8) for DENV3, DENV2, DENV1, and DENV4, respectively.

CONCLUSION

CYD-TDV vaccine is effective and immunogenic in children overall. Reduced efficacy of CYD-TDV vaccine against DENV2 notoriously known for causing severe dengue infection and dengue outbreaks cause for serious concern. Post hoc meta-analysis of long-term follow-up data (≥25 months) from children previously vaccinated with CYD-TDV vaccine is needed to make a conclusion regarding CYD-TDV vaccine safety in children. However, CYD-TDV vaccine should be considered for use in regions where DENV2 is not endemic as currently there is no specific treatment for dengue infection.

Current management of severe dengue infection

INTRODUCTION

Traditionally a disease mainly affecting the pediatric population, dengue burden has increased significantly in recent decades and adults with severe disease may become more common. There is currently no effective anti-viral agent available for the treatment of dengue and supportive care is the mainstay of management. Areas covered: We present a review of current literature on dengue severity classification systems and the management of severe dengue in adults. In particular, emphasis was placed on organ impairment in dengue and management of elderly individuals with multiple medical problems. Expert commentary: There is an urgent need to search for an effective anti-viral agent to treat infected individuals. The commercial availability of a dengue vaccine in older children has provided optimism in reducing the disease burden but long term efficacy and safety are unknown. The results from phase III trials of two new candidate vaccines are eagerly awaited.

Outcome of Severe Dengue Viral Infection-caused Acute Liver Failure in Thai Children

To determine clinical course and outcomes of liver functions in children with dengue viral infection-caused acute liver failure (ALF), the records of patients aged <15 years attending our institution during 1989-2011 were reviewed. Of the 41 ALF patients, 2, 6 and 33 patients had dengue hemorrhagic fever grade II, III and IV, respectively. Multiorgan failure including respiratory failure, massive bleeding and acute kidney injury occurred in 80.0%, 96.0% and 84.0% of the ALF cases, respectively, with an overall fatality rate of 68.3%. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were highest on the day that the patient developed ALF. Lactate dehydrogenase levels had positive correlations with AST (r = 0.95) and ALT (r = 0.87) (all p < 0.01). The median (interquartile range) days before the AST and ALT levels returned to lower than 200 U/L after the ALF were 10.5 (8.8, 12.8) and 10.5 (7.8, 14.0) days, respectively.

Changing pattern of dengue virus serotypes circulating during 2008-2012 and reappearance of dengue serotype 3 may cause outbreak in Kolkata, India

Dengue virus infection is a major cause of morbidity within the endemic tropical and subtropical regions of the world. Dengue virus has four distinct serotypes with specific clinical manifestations. In this study, we observed the changing pattern of dengue serotypes, age-wise dengue infection and useful sero-detection methods needed in a dengue endemic region. We identified dengue serotypes during a period of 5 years among patients with dengue symptoms visiting one of the largest tertiary care infectious disease hospitals of eastern India in Kolkata. A total of 433 dengue RNA positive samples were isolated from 712 acute dengue suspected cases. Age wise distribution highlighted the susceptible age group being >21 years (24.02%) followed by 11-15 years (21.71%) and 5-10 years (21.02%) of the total infected population. Higher numbers of infected cases were found within females as they are involved in more indoor works. The period of study experienced two dengue outbreaks one in 2008 and another in 2012. For early dengue detection, NS1 was found to be more confirmatory than IgM ELISA regarding sensitivity and specificity. DENV-1, 2, and 4 serotypes were the common circulating strains from 2008 until 2010, after which DENV-3 serotype infections rise and led to a massive dengue outbreak in Kolkata with increased numbers of DHF and DSS cases in 2012. The finding within our study emphasizes the public health importance of such prospective surveillance programs with respect to the changing dengue viral etiology and serotypes. J. Med. Virol. 88:1697-1702, 2016. © 2016 Wiley Periodicals, Inc.

Pathogenesis of Dengue: Dawn of a New Era

Dengue virus (DENV) infections of humans were long thought to be self-limited and of low mortality. Beginning in the 1950s, at the time when four different DENVs were discovered, a lethal variant of dengue emerged. Dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) initially observed in Southeast Asia now has spread throughout the world. Two risk factors for DHF/DSS are well-established: severe disease occurs during a second heterotypic DENV infection or during a first DENV infection in infants born to dengue-immune mothers. A large number of hypotheses have been proposed to explain severe dengue disease. As discussed, few of them attempt to explain why severe disease occurs under the two different immunological settings. New experimental evidence has demonstrated that DENV non-structural protein 1 (NS1) is toll-receptor 4 agonist that stimulates primary human myeloid cells to produce the same cytokines observed during the course of severe dengue disease. In addition, NS1 directly damages endothelial cells. These observations have been repeated and extended to an in vivo mouse model. The well-established phenomenon, antibody-dependent enhancement of DENV infection in Fc-receptor-bearing cells, should similarly enhance the production of DENV NS1 in humans, providing a unitary mechanism for severe disease in both immunological settings.

Factors associated with death from dengue in the state of Minas Gerais, Brazil: historical cohort study

OBJECTIVES

To analyse the clinical and epidemiological profiles of dengue haemorrhagic fever (DHF), dengue shock syndrome (DSS) and complicated dengue cases and deaths from 2008 to 2010 that occurred in the state of Minas Gerais, south-eastern Brazil, and to identify factors associated with death from dengue.

METHODS

Historical cohort study using data from the Brazilian Information System for Notifiable Diseases. A descriptive analysis of the DHF, DSS and complicated dengue cases and deaths was performed; the incidence, mortality and case-fatality rates were estimated. Logistic regression analysis was used to identify factors associated with death from dengue. Comorbidities were not included in the analysis because the information system does not contain such data.

RESULTS

During the study period, 2214 DHF, DSS and complicated dengue cases were reported, including 156 deaths. The annual case-fatality rates for DHF/DSS and complicated dengue cases in the period of 2008-2010 were 7.3%, 4.8% and 7.9%, respectively. The factors associated with death from dengue included residence in a municipality with a population of fewer than 100,000 inhabitants [odds ratio (OR) 2.46; 95% confidence interval (CI) 1.71-3.55], age over 65 years (OR 3.05; 95% CI 1.99-4.68) and plasma leakage (OR 1.69; 95% CI 1.16-2.46).

CONCLUSIONS

The results support the importance of plasma leakage as a warning sign associated with death from dengue as well as the signs and symptoms that allow the diagnosis of DHF. Moreover, our findings suggest that increased attention is necessary for individuals over 65 years of age and in municipalities with populations under 100,000 inhabitants to ensure a better quality of care during the management of severe patients of dengue in these locations. Differences in the interpretation of the DHF definition have hindered the comparison of data from different countries; it can improve from the WHO 2009 dengue classification.

Validation of dengue infection severity score

Objective

To validate a simple scoring system to classify dengue viral infection severity to patients in different settings.

Methods

The developed scoring system derived from 777 patients from three tertiary-care hospitals was applied to 400 patients in the validation data obtained from another three tertiary-care hospitals. Percentage of correct classification, underestimation, and overestimation was compared. The score discriminative performance in the two datasets was compared by analysis of areas under the receiver operating characteristic curves.

Results

Patients in the validation data were different from those in the development data in some aspects. In the validation data, classifying patients into three severity levels (dengue fever, dengue hemorrhagic fever, and dengue shock syndrome) yielded 50.8% correct prediction (versus 60.7% in the development data), with clinically acceptable underestimation (18.6% versus 25.7%) and overestimation (30.8% versus 13.5%). Despite the difference in predictive performances between the validation and the development data, the overall prediction of the scoring system is considered high.

Conclusion

The developed severity score may be applied to classify patients with dengue viral infection into three severity levels with clinically acceptable under- or overestimation. Its impact when used in routine clinical practice should be a topic for further study.

Clinical characteristics of Dengue shock syndrome in Vietnamese children: a 10-year prospective study in a single hospital

BACKGROUND

Dengue shock syndrome (DSS) is a severe manifestation of dengue virus infection that particularly affects children and young adults. Despite its increasing global importance, there are no prospective studies describing the clinical characteristics, management, or outcomes of DSS.

METHODS

We describe the findings at onset of shock and the clinical evolution until discharge or death, from a comprehensive prospective dataset of 1719 Vietnamese children with laboratory-confirmed DSS managed on a single intensive care unit between 1999 and 2009.

RESULTS

The median age of patients was 10 years. Most cases had secondary immune responses, with only 6 clear primary infections, and all 4 dengue virus serotypes were represented during the 10-year study. Shock occurred commonly between days 4 and 6 of illness. Clinical signs and symptoms were generally consistent with empirical descriptions of DSS, although at presentation 153 (9%) were still febrile and almost one-third had no bleeding. Overall, 31 (2%) patients developed severe bleeding, primarily from the gastrointestinal tract, 26 of whom required blood transfusion. Only 8 patients died, although 123 of 1719 (7%) patients had unrecordable blood pressure at presentation and 417 of the remaining 1596 (26%) were hypotensive for age. The majority recovered well with standard crystalloid resuscitation or following a single colloid infusion. All cases were classified as severe dengue, while only 70% eventually fulfilled all 4 criteria for the 1997 World Health Organization classification of dengue hemorrhagic fever.

CONCLUSIONS

With prompt intervention and assiduous clinical care by experienced staff, the outcome of this potentially fatal condition can be excellent.

Dengue viruses - an overview

Dengue viruses (DENVs) cause the most common arthropod-borne viral disease in man with 50-100 million infections per year. Because of the lack of a vaccine and antiviral drugs, the sole measure of control is limiting the Aedes mosquito vectors. DENV infection can be asymptomatic or a self-limited, acute febrile disease ranging in severity. The classical form of dengue fever (DF) is characterized by high fever, headache, stomach ache, rash, myalgia, and arthralgia. Severe dengue, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) are accompanied by thrombocytopenia, vascular leakage, and hypotension. DSS, which can be fatal, is characterized by systemic shock. Despite intensive research, the underlying mechanisms causing severe dengue is still not well understood partly due to the lack of appropriate animal models of infection and disease. However, even though it is clear that both viral and host factors play important roles in the course of infection, a fundamental knowledge gap still remains to be filled regarding host cell tropism, crucial host immune response mechanisms, and viral markers for virulence.

Development of specific dengue virus 2'-O- and N7-methyltransferase assays for antiviral drug screening

Dengue virus (DENV) protein NS5 carries two mRNA cap methyltransferase (MTase) activities involved in the synthesis of a cap structure, (7Me)GpppA(2'OMe)-RNA, at the 5'-end of the viral mRNA. The methylation of the cap guanine at its N7-position (N7-MTase, (7Me)GpppA-RNA) is essential for viral replication. The development of high throughput methods to identify specific inhibitors of N7-MTase is hampered by technical limitations in the large scale synthesis of long capped RNAs. In this work, we describe an efficient method to generate such capped RNA, GpppA(2'OMe)-RNA₇₄, by ligation of two RNA fragments. Then, we use GpppA(2'OMe)-RNA₇₄ as a substrate to assess DENV N7-MTase activity and to develop a robust and specific activity assay. We applied the same ligation procedure to generate (7Me)GpppA-RNA₇₄ in order to characterize the DENV 2'-O-MTase activity specifically on long capped RNA. We next compared the N7- and 2'-O-MTase inhibition effect of 18 molecules, previously proposed to affect MTase activities. These experiments allow the validation of a rapid and sensitive method easily adaptable for high-throughput inhibitor screening in anti-flaviviral drug development.

Host genetic susceptibility to severe dengue infection

Epidemiological evidence indicates that host genetic factors are relevant and predispose DHF/DSS development. Here, we review the host genetic studies concerning human leucocyte antigens, antibody receptors, immune/inflammatory mediators, attachment molecules, cytokines and other factors exerting an immunoregulatory effect as well as the current genome-wide association studies. We also discuss some viewpoints on future challenges related to the design of safe and effective prevention and treatment options.

Clinical manifestations and trend of dengue cases admitted in a tertiary care hospital, udupi district, karnataka

Background:

India is one of the seven identified countries in the South-East Asia region regularly reporting dengue fever (DF)/dengue hemorrhagic fever (DHF) outbreaks and may soon transform into a major niche for dengue infection in the future with more and more new areas being struck by dengue epidemics

Objective:

To study the clinical manifestations, trend and outcome of all confirmed dengue cases admitted in a tertiary care hospital.

Study Design:

Record-based study conducted in a coastal district of Karnataka. Required data from all the laboratory confirmed cases from 2002 to 2008 were collected from Medical Records Department (MRD) and analyzed using SPSS 13.5 version.

Results:

Study included 466 patients. Majority were males, 301(64.6%) and in the and in the age group of 15-44 years, 267 (57.5%). Maximum number of cases were seen in 2007, 219 (47%) and in the month of September, 89 (19.1%). The most common presentation was fever 462 (99.1%), followed by myalgia 301 (64.6%), vomiting 222 (47.6%), headache 222 (47.6%) and abdominal pain 175 (37.6%). The most common hemorrhagic manifestation was petechiae 84 (67.2%). 391 (83.9%) cases presented with dengue fever, 41 (8.8%) dengue hemorrhagic fever, and 34 (7.3%) with dengue shock syndrome. Out of 66 (14.1%) patients who developed clinical complications, 22 (33.3%) had ARDS and 20 (30.3%) had pleural effusion. Deaths reported were 11(2.4%).

Conclusion:

Community awareness, early diagnosis and management and vector control measures need to be strengthened, during peri-monsoon period, in order to curb the increasing number of dengue cases.

Persistent thrombocytopenia following dengue shock syndrome

Though thrombocytopenia is one of the hallmarks of dengue hemorrhagic fever/ dengue shock syndrome, persistence of the same is rare. We report an 11 year-old child with dengue shock syndrome, who developed persistent thrombocytopenia. The possible mechanisms are discussed.

Clinical features, complications and atypical manifestations of children with severe forms of dengue hemorrhagic fever in South India

OBJECTIVE

To review clinical features and outcome of children with severe forms of dengue hemorrhagic fever (DHF) presenting to a pediatric intensive care unit (PICU) with particular focus on clinical presentation and outcome.

METHODS

Retrospective chart review of patients admitted to the Pediatric Intensive Care Unit (PICU) of a referral children's hospital in South India with DHF over 1.5 years (2001-January 2003).

RESULTS

Of 858 patients with dengue fever/DHF admitted to the hospital during the study period, 109 cases with severe forms of disease required PICU admission, of which 9 patients died. 77 were under 5 years of age. The commonest indication for PICU admission was persistent shock (39 patients) followed by requirement for positive pressure ventilation in 29 patients (10 of whom had Acute Respiratory Distress Syndrome [ARDS]) and neurological symptoms in 24 patients. An important finding was the presence of diastolic dysfunction in 3 children. Six deaths of refractory shock included 4 who had ARDS and DIC and 2 who had shock with DIC 3 patients had abdominal compartment syndrome (ACS) has not been previously described in children with DSS and may lead to fluid refractory shock if not corrected. All patients had thrombocytopenia which was a defining feature of the syndrome, while 74 were also coagulopathic and 6 had severe fatal DIC. Hepatic dysfunction was more severe in children with prolonged shock, however, only a fifth of cases (5/24) with neurological manifestations were in shock. Other significant reasons for neurological presentation included cerebral edema and encephalopathy secondary to hepatic dysfunction. 2 children had features of Acute Disseminated Encephalomyelitis (ADEM), previously only described in adults with dengue.

CONCLUSION

It was found that complications such as DIC, diastolic dysfunction, abdominal compartment syndrome, ARDS and hepatic dysfunction were more frequent in severe established shock. However, most neurological events were unrelated to the perfusion status. Children referred late were harder to resuscitate. There were 9 PICU deaths (case fatality rate of 8.35%). Severe refractory shock, DIC, ARDS, hepatic failure and neurological manifestations singly or in combination were the commonest causes of death in the present study.

First outbreak of dengue hemorrhagic fever, Bangladesh

During the first countrywide outbreak of dengue hemorrhagic fever in Bangladesh, we conducted surveillance for dengue at a hospital in Dhaka. Of 176 patients, primarily adults, found positive for dengue, 60.2% had dengue fever, 39.2% dengue hemorrhagic fever, and 0.6% dengue shock syndrome. The Dengue virus 3 serotype was detected in eight patients.