Value of peripheral blood count for dengue severity prediction

Platelet derived exosomes disrupt endothelial cell monolayer integrity and enhance vascular inflammation in dengue patients

Background

Thrombocytopenia is the most notable phenomenon in dengue. Activation status of platelets and interaction of platelets with endothelium contribute towards dengue disease pathogenesis. Platelets are the major cell types known to release extracellular vesicles, especially exosomes in circulation. However, the role of platelet derived exosomes (PLT-EXOs) in endothelial dysfunction during dengue infection remains unknown.

Methods

In this study, we recruited 28 healthy subjects and 69 dengue patients categorized as WS- (n=31), WS+ (n=29) and SD (n=9). Platelets were isolated from platelet rich plasma of dengue patients and their activation was assessed by flow cytometry. PLT-EXOs were isolated by ultracentrifugation method. Western blot analyses were performed to characterize the exosomes. Exosome uptake experiment was carried out to see the internalization of exosomes inside endothelial cells (HUVECs). To observe the effect of exosomes on endothelial cells, exosomes were added on HUVECs and expression of adherens and tight junctional proteins were examined by immunofluorescence assay and western blot. Expression levels of vascular injury markers were measured in the culture supernatants of Exosome-HUVEC coculture and sera of dengue patients by MSD-multiplex assay.

Results

As compared to healthy subjects, CD41/CD61 expression was significantly reduced (p<0.0001) and CD62p expression was significantly increased (p<0.0001) on platelets in dengue patients. PLT-EXOs isolated from the dengue patients showed higher expression of CD63 and CD9 proteins than the healthy subjects. With in-vitro immunofluorescence assays, we illustrated the internalization of PLT-EXOs by the HUVECs and observed disruption of endothelial cell monolayer integrity in the presence of PLT-EXOs from WS+ and SD patients. Furthermore, the significant reduction in the expressions of ZO-2, VE-Cadherin and CD31 in endothelial cells following exposure to PLT-EXOs from the dengue patients provide direct evidence of PLT-EXOs mediated vascular permeability. PLT-EXOs stimulated the release of inflammatory markers CRP, SAA, sVCAM-1 and sICAM-1 in the supernatants of HUVEC cells. Importantly, significantly higher levels of CRP, sVCAM-1 and sICAM-1 in the sera of severe than mild dengue patients (p<0.0001) suggest their role in disease severity.

Conclusions

In summary, our data suggest that PLT-EXOs promote vascular leakage via release of proinflammatory mediators and compromise vascular barrier integrity in dengue patients.

Non-structural protein 1 and hematology parameters as predictors of dengue virus infection severity in Indonesia

Dengue virus infection (DVI) remains a significant health challenge, and diagnosis must still be considered. Non-structural protein 1 (NS1) is a potential marker of the dengue virus that can help diagnose DVI. The study aimed to assess the role of NS1 as a predictor of the severity of DVI. We utilized Dengue PCR-confirmed samples and employed semi-quantitative NS1Ag ELISA for NS1 examination, adhering to the World Health Organization South-East Asia Region (WHO-SEARO) 2011 criteria for DVI. We included DVI patients from Indonesia aged 1-65 years. Secondary infections had more severe clinical conditions than primary infections. Leukocyte and platelet levels had a more significant effect on NS1 positivity (6.19 (1.9-30.2); p<0.001; 190 (11-417); p=0.015; respectively). Multivariate analysis revealed leukocytes as a more significant predictor of NS1 values than platelets, with an odds ratio of 5.38 contributing to 30.5% of the NS1 value variation. The NS1 value could distinguish undifferentiated fever and dengue fever in the children group with a sensitivity of 76.0% and specificity of 87.5% (p=0.015). The number of NS1(-) in the severe dengue hemorrhagic fever (DHF) group was higher than NS1(+). DENV-4 type and primary infection were dominant in this study, although they did not significantly differ from the NS1 value. NS1 value can be used as a predictor to determine the severity of DVI in children but not in the adult group. The levels of leukocytes and platelets influenced the NS1 value.

Early transcriptomic host response signatures in the serum of dengue patients provides insights into clinical pathogenesis and disease severity

Dengue virus (DENV), known to cause viral infection, belongs to the family Flaviviridae, having four serotypes (DENV1-4) that spreads by the bite of the Aedes aegypti mosquito. India has been suffering from dengue outbreaks annually with widespread epidemics by prevalence of all the four DENV serotypes. The diverse spectrum of clinical manifestations in dengue infection, mild to severe forms, makes the need of timely diagnosis and prompt treatment an essence. The identification of a dengue host response signature in serum can increase the understanding of dengue pathogenesis since most dengue NS1 Ag tests have been developed and evaluated in serum samples. Here, to understand the same, we undertook a dual RNA-sequencing (RNA-Seq) based approach from the serum samples of dengue-infected patients. The results thus yield the early transcriptional signatures that discriminated the high viral reads patients from patients who had low dengue viral reads. We identified a significant upregulation of two sets of genes, key antiviral (IFIT3, RSAD2, SAT1) and vascular dysfunction (TNFS10, CXCL8) related genes in the high viral reads group. Deeper delving of this gene profile revealed a unique two-way response, where the antiviral genes can mediate the disease course to mild, contrarily the increased expression of the other gene set might act as pointers of severe disease course. Further, we explored the hematologic parameters from the complete blood count (CBC), which suggests that lymphocytes (low) and neutrophils (high) might serve as an early predictor of prognosis in dengue infection. Collectively, our findings give insights into the foundation for further investigation of the early host response using the RNA isolated from dengue patients' serum samples and opens the door for careful monitoring of the early clinical and transcriptome profiles for management of the dengue patients.

Integrated clinical and metabolomic analysis of dengue infection shows molecular signatures associated with host-pathogen interaction in different phases of the disease

PURPOSE

Dengue is a mosquito vector-borne disease caused by the dengue virus, which affects 125 million people globally. The disease causes considerable morbidity. The disease, based on symptoms, is classified into three characteristic phases, which can further lead to complications in the second phase. Molecular signatures that are associated with the three phases have not been well characterized. We performed an integrated clinical and metabolomic analysis of our patient cohort and compared it with omics data from the literature to identify signatures unique to the different phases.

METHODS

The dengue patients are recruited by clinicians after standard-of-care diagnostic tests and evaluation of symptoms. Blood from the patients was collected. NS1 antigen, IgM, IgG antibodies, and cytokines in serum were analyzed using ELISA. Targeted metabolomics was performed using LC-MS triple quad. The results were compared with analyzed transcriptomic data from the GEO database and metabolomic data sets from the literature.

RESULTS

The dengue patients displayed characteristic features of the disease, including elevated NS1 levels. TNF-α was found to be elevated in all three phases compared to healthy controls. The metabolic pathways were found to be deregulated compared to healthy controls only in phases I and II of dengue patients. The pathways represent viral replication and host response mediated pathways. The major pathways include nucleotide metabolism of various amino acids and fatty acids, biotin, etc. CONCLUSION: The results show elevated TNF-α and metabolites that are characteristic of viral infection and host response. IL10 and IFN-γ were not significant, consistent with the absence of any complications.

Study of Hepatic Dysfunction Associated with Dengue Epidemiology in a Tertiary Care Hospital, Kolkata

Dengue is a common arthropod-borne life-threatening febrile illness. This disease affects liver functions with an imbalance of liver enzymes followed by other clinical manifestations. The dengue serotypes can cause asymptomatic infection to more severe versions of hemorrhagic fever and dengue shock syndrome in West Bengal and around the globe. The main aim of this study is to establish how different liver enzymes act in identifying markers for dengue prognosis for the early detection of severe dengue fever (DF). The diagnosis of dengue patients was confirmed by enzyme-linked immunosorbent assay, and associated clinical parameters [aspartate transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase, total bilirubin, total albumin, total protein, packed cell volume, and platelet count] were analyzed. Furthermore, the viral load estimation was also carried out by RT PCR analysis. The majority of these patients had elevated AST and ALT levels; ALT levels were higher than AST levels, which were partially observed in all non-structural protein 1 antigen- and dengue immunoglobulin M antibody-reactive patients. Almost 25% of patients had very low platelet count or thrombocytopenia. Furthermore, the viral load shows a significant association with all the clinical parameters with a p-value of <0.0001. All these liver enzymes are significantly correlated with an increased level of T.BIL, ALT, and AST. This study depicts that the intensity of hepatic involvement may play a critical role in the morbidity and mortality of DF patients. As a result, all of these liver parameters can be useful early markers for determining the severity of the disease, allowing for early detection of high-risk cases.

Machine Learning-Based Detection of Dengue from Blood Smear Images Utilizing Platelet and Lymphocyte Characteristics

Dengue fever, also known as break-bone fever, can be life-threatening. Caused by DENV, an RNA virus from the Flaviviridae family, dengue is currently a globally important public health problem. The clinical methods available for dengue diagnosis require skilled supervision. They are manual, time-consuming, labor-intensive, and not affordable to common people. This paper describes a method that can support clinicians during dengue diagnosis. It is proposed to automate the peripheral blood smear (PBS) examination using Artificial Intelligence (AI) to aid dengue diagnosis. Nowadays, AI, especially Machine Learning (ML), is increasingly being explored for successful analyses in the biomedical field. Digital pathology coupled with AI holds great potential in developing healthcare services. The automation system developed incorporates a blob detection method to detect platelets and thrombocytopenia from the PBS images. The results achieved are clinically acceptable. Moreover, an ML-based technique is proposed to detect dengue from the images of PBS based on the lymphocyte nucleus. Ten features are extracted, including six morphological and four Gray Level Spatial Dependance Matrix (GLSDM) features, out of the lymphocyte nucleus of normal and dengue cases. Features are then subjected to various popular supervised classifiers built using a ten-fold cross-validation policy for automated dengue detection. Among all the classifiers, the best performance was achieved by Support Vector Machine (SVM) and Decision Tree (DT), each with an accuracy of 93.62%. Furthermore, 1000 deep features extracted using pre-trained MobileNetV2 and 177 textural features extracted using Local binary pattern (LBP) from the lymphocyte nucleus are subjected to feature selection. The ReliefF selected 100 most significant features are then fed to the classifiers. The best performance was attained using an SVM classifier with 95.74% accuracy. With the obtained results, it is evident that this proposed approach can efficiently contribute as an adjuvant tool for diagnosing dengue from the digital microscopic images of PBS.

Dengue: Update on Clinically Relevant Therapeutic Strategies and Vaccines

Dengue viruses (DENV) continue to circulate worldwide, resulting in a significant burden on human health. There are four antigenically distinct serotypes of DENV, an infection of which could result in a potentially life-threatening disease. Current treatment options are limited and rely on supportive care. Although one dengue vaccine is approved for dengue-immune individuals and has modest efficacy, there is still a need for therapeutics and vaccines that can reduce dengue morbidities and lower the infection burden. There have been recent advances in the development of promising drugs for the treatment of dengue. These include direct antivirals that can reduce virus replication as well as host-targeted drugs for reducing inflammation and/or vascular pathologies. There are also new vaccine candidates that are being evaluated for their safety and efficacy in preventing dengue disease. This review highlights nuances in the current standard-of-care treatment of dengue. We also discuss emerging treatment options, therapeutic drugs, and vaccines that are currently being pursued at various stages of preclinical and clinical development.

Shapley-Additive-Explanations-Based Factor Analysis for Dengue Severity Prediction using Machine Learning

Dengue is a viral disease that primarily affects tropical and subtropical regions and is especially prevalent in South-East Asia. This mosquito-borne disease sometimes triggers nationwide epidemics, which results in a large number of fatalities. The development of Dengue Haemorrhagic Fever (DHF) is where most cases occur, and a large portion of them are detected among children under the age of ten, with severe conditions often progressing to a critical state known as Dengue Shock Syndrome (DSS). In this study, we analysed two separate datasets from two different countries– Vietnam and Bangladesh, which we referred as VDengu and BDengue, respectively. For the VDengu dataset, as it was structured, supervised learning models were effective for predictive analysis, among which, the decision tree classifier XGBoost in particular produced the best outcome. Furthermore, Shapley Additive Explanation (SHAP) was used over the XGBoost model to assess the significance of individual attributes of the dataset. Among the significant attributes, we applied the SHAP dependence plot to identify the range for each attribute against the number of DHF or DSS cases. In parallel, the dataset from Bangladesh was unstructured; therefore, we applied an unsupervised learning technique, i.e., hierarchical clustering, to find clusters of vital blood components of the patients according to their complete blood count reports. The clusters were further analysed to find the attributes in the dataset that led to DSS or DHF.

Dynamic Changes of Platelet and Factors Related Dengue Haemorrhagic Fever: A Retrospective Study in Indonesian

Dengue is a viral infection caused by the dengue virus (DENV). Dengue infection is a self-limited acute febrile illness caused by four serotypes of DENV (DENV-1~4). Early recognition of high-risk patients would be helpful to reduce mortality rates and prevent severe dengue. Our study aimed to identify factors related to dengue hemorrhagic fever (DHF) based on admission-day data, and further to understand the distribution of biochemical laboratory data in dengue patients. This retrospective study was conducted in hospitals in Yogyakarta city, Indonesia, and involved febrile patients who were admitted to the hospital with a diagnosis of dengue during 2018 and 2020. Logistic regression models were used to identify variables related to DHF. In this study, 1087 patients were included as suspected dengue patients, among them 468 had dengue fever (DF) and 619 had DHF. Over half of the DHF patients were males (55.9%) with an average age of 17.9 years, and with a secondary infection (71.3%). By a multivariate analysis, on-admission laboratory data of thrombocytopenia and hemoglobin showed significant association with DHF. Furthermore, DHF patients had significantly prolonged hospitalizations compared to DF patients. In conclusion, on-admission platelet counts and hemoglobin laboratory data are useful as predictors of DHF especially for suspected dengue patients with the limitations of diagnostic tests.

A Comparison of the Accuracy of Handheld Hemoglobinometer and Hematocrit Measurements for Detecting Plasma Leakage in Dengue Hemorrhagic Fever

Purpose

Practical methods for detecting plasma leakage should be readily available in all areas where dengue is endemic. We compared the accuracy of measurements obtained with a handheld HemoCue^® Hb 201 instrument used for hemoglobin point-of-care testing (Hb-POCT) with that of measurements of hematocrit (Ht) levels for detecting plasma leakage in dengue patients.

Patients and Methods

We performed both measurements using the HemoCue^® Hb201 system and microhematocrit method on EDTA blood taken from dengue patients at three time points during their hospitalization. Ascites, pleural effusion, or gallbladder thickening determined through ultrasound examinations were considered the gold standard for determining dengue hemorrhagic fever (DHF) versus dengue fever (DF).

Results

Close agreement between Hb-POCT and Ht measurements was indicated by an r square value of 0.845 in a linear regression. The sensitivity results for distinguishing between DHF and DF at admission were similar for Hb-POCT (63.6%) and Ht (66.7%) (Kappa = 0.75) using the optimal cutoff point determined via ROC analysis. Delta differences (in percentage) for Hb-POCT and Ht between the highest and lowest values showed lower sensitivity (45.5% and 48.5%, respectively; Kappa 0.60) when the optimal cutoff point was applied. Recommended cutoffs of ≥20% to confirm plasma leakage provided a slightly higher sensitivity using Hb-POCT (18.2%) compared with the sensitivity obtained using Ht (15.2%) with Kappa value of 97.9%.

Conclusion

Our results showed that the accuracy of Hb POCT measurements was similar and not inferior to Ht measurements for detecting plasma leakage in patients with DHF. We recommend that further evaluations are conducted to determine the optimal cutoff point given the low sensitivity associated with using ≥20% Hb-POCT or Ht increases to determine hemoconcentration.

The Role of Angiopoietin-2 on Plasma Leakage in the Critical Phase and Convalescence of Dengue Virus Infection in Children

Abstract Background: The worst complication of dengue haemorrhagic fever (DHF) that lead to death is hypovolemic shock due to plasma leakage from intravascular to extravascular space caused by endothelial dysfunction. This study is aimed to analyze the difference of Ang-2 level in dengue haemorrhagic fever patients related to plasma leakage between critical phase and convalescence.   Aim: One hundred and ten children with DHF confirmed serologically with positive IgM anti-dengue or IgM and IgG anti-dengue were recruited in this study. We examine the clinical manifestations, laboratory parameters (platelet count, AST and ALT levels), and molecular test (Ang-2). The molecular indicator was tested by Enzyme-Linked Immunosorbent Assay (ELISA). Data were collected between July – November 2019. This is an observational study with cross-sectional comparative design.   Results: In our study, we found correlation of clinical symptoms (abdominal pain, persistent vomit, and hepatomegaly) with the occurrence of plasma leakage in DHF patients. We also found that Ang-2 level is significantly higher in children with DHF during critical phase compared to convalescence (p< 0.01).   Conclusion: There is a significant difference of Ang-2 level in DHF patients during critical phase and convalescence.   Keywords: Dengue hemorrhagic fever, children, Ang-2, critical phase, convalescence

The Usefulness of Peripheral Blood Cell Counts to Distinguish COVID-19 from Dengue during Acute Infection

COVID-19 and dengue disease are challenging to tell apart because they have similarities in clinical and laboratory features during the acute phase of infection, leading to misdiagnosis and delayed treatment. The present study evaluated peripheral blood cell count accuracy to distinguish COVID-19 non-critical patients from non-severe dengue cases between the second and eleventh day after symptom onset. A total of 288 patients infected with SARS-CoV-2 (n = 105) or dengue virus (n = 183) were included in this study. Neutrophil, platelet, and lymphocyte counts were used to calculate the neutrophil–lymphocyte ratio (NLR), the platelet–lymphocyte ratio (PLR), and the neutrophil–lymphocyte*platelet ratio (NLPR). The logistic regression and ROC curves analysis revealed that neutrophil and platelet counts, NLR, LPR, and NLPR were higher in COVID-19 than dengue. The multivariate predictive model showed that the neutrophils, platelets, and NLPR were independently associated with COVID-19 with a good fit predictive value (p = 0.1041). The neutrophil (AUC = 0.95, 95% CI = 0.84–0.91), platelet (AUC = 0.89, 95% CI = 0.85–0.93) counts, and NLR (AUC = 0.88, 95% CI = 0.84–0.91) were able to discriminate COVID-19 from dengue with high sensitivity and specificity values (above 80%). Finally, based on predicted probabilities on combining neutrophils and platelets with NLR or NLPR, the adjusted AUC was 0.97 (95% CI = 0.94–0.98) to differentiate COVID-19 from dengue during the acute phase of infection with outstanding accuracy. These findings might suggest that the neutrophil, platelet counts, and NLR or NLPR provide a quick and cost-effective way to distinguish between dengue and COVID-19 in the context of co-epidemics in low-income tropical regions.

The Future of Carica papaya Leaf Extract as an Herbal Medicine Product

Carica papaya (papaya) leaf extract has been used for a long time in a traditional medicine to treat fever in some infectious diseases such as dengue, malaria, and chikungunya. The development of science and technology has subsequently made it possible to provide evidence that this plant is not only beneficial as an informal medication, but also that it has scientifically proven pharmacological and toxicological activities, which have led to its formal usage in professional health care systems. The development of formulations for use in nutraceuticals and cosmeceuticals has caused this product to be more valuable nowadays. The use of good manufacturing practice (GMP) standards, along with the ease of registering this product facilitated by policies of the national government, will absolutely increase the value of papaya leaf extract as a vital nutraceutical and cosmeceutical products in the near future. In this article, we review the potential of papaya leaf extract to be a high-value commodity in terms of its health effects as well as its industrial benefits.

An economic evaluation of implementing a decentralized dengue screening intervention under the National Vector Borne Disease Control Programme in Tamil Nadu, South India

Background

Lack of effective early screening is a major obstacle for reducing the fatality rate and disease burden of dengue. In light of this, the government of Tamil Nadu has adopted a decentralized dengue screening strategy at the primary healthcare (PHC) facilities using blood platelet count. Our objective was to determine the cost-effectiveness of a decentralized screening strategy for dengue at PHC facilities compared with the current strategy at the tertiary health facility (THC) level.

Methods

Decision tree analysis followed a hypothetical cohort of 1000 suspected dengue cases entering the model. The cost-effectiveness analysis was performed at a 3% discount rate for the proposed and current strategy. The outcomes are expressed in incremental cost-effectiveness ratios (ICERs) per quality-adjusted life years gained. One-way sensitivity analysis and probabilistic sensitivity analysis were done to check the uncertainty in the outcome.

Results

The proposed strategy was found to be cost-saving and ICER was estimated to be −41 197. PSA showed that the proposed strategy had a 0.84 probability of being an economically dominant strategy.

Conclusions

The proposed strategy is cost-saving, however, it is recommended to consider optimal population coverage, costs to economic human resources and collateral benefits of equipment.

Comparison between blood hemoglobin concentration determined by point-of-care device and complete blood count in adult patients with dengue

Background

Hematocrit measurement has been an indispensable tool for monitoring plasma leakage and bleeding in dengue patients. However, hematocrit measurement by automated methods is hampered by frequent venipunctures. Utility of point-of-care hemoglobin (POC-Hb) test for monitoring dengue patients has not been established. We evaluated the relationship between hemoglobin measured by POC-Hb testing and hematocrit measured by the automated method in adult dengue patients.

Methodology and principal findings

Adult dengue patients were recruited at two university hospitals in Thailand from October 2019 to December 2020. POC-Hb test was performed using capillary blood simultaneously with venipuncture to obtain whole blood for an automated complete blood count (CBC) analysis. The correlation of hemoglobin and hematocrit measurement was evaluated. A total of 44 dengue patients were enrolled. Twenty-nine patients (65.9%) were female, with a median age of 31 years (interquartile range 22–41). Of the enrolled patients, 30 (68.2%), 11 (25.0%), and 3 (6.8%) were classified as dengue without warning signs, with warning signs, and severe dengue, respectively. Seven patients (15.9%) had hemoconcentration, and five patients (11.3%) had bleeding. A total of 216 pairs of POC-Hb and CBC were evaluated. A significant positive correlation was observed between hemoglobin measured by POC-Hb testing and hematocrit measured by an automated CBC (r = 0.869, p <0.001). Bland-Altman analysis between hemoglobin measured by POC-Hb testing and an automated CBC showed a bias of -0.43 (95% limit of agreement of -1.81 and 0.95). Using the cutoff of POC-Hb ≥20% as a criteria for hemoconcentration, the sensitivity and specificity of hemoconcentration detected by POC-Hb device were 71.4% and 100.0%, respectively.

Conclusions

Hemoglobin measurement by POC-Hb testing has a strong correlation with hematocrit in adult patients with dengue fever. However, the sensitivity in detecting hemoconcentration is fair. The adjunct use of capillary POC-Hb testing can decrease the frequency of venipuncture. Further study in children is encouraged.

The natural history of dengue has the unique characteristic of plasma leakage that results in hemoconcentration as well as vasculopathy and thrombocytopenia that result in bleeding. Therefore, hematocrit monitoring is a crucial tool to guide management in dengue patients. Microhematocrit adjunct with a complete blood count (CBC) to monitor dengue patients were traditionally performed to decrease the frequency of venipuncture. However, microhematocrit is currently less preferred to the point-of-care hemoglobin monitoring tools to measure red cells in other diseases. There has been no study investigating the feasibility of using point-of-care hemoglobin (POC-Hb) to monitor dengue patients. We studied the correlation of hemoglobin measured by POC-Hb testing and hematocrit measured by an automated CBC in adult dengue patients. We were able to show a strong positive correlation between the two measurements (r = 0.869, p <0.001). Using the rise of POC-Hb value of ≥20% above the convalescent value as the criteria for detecting hemoconcentration by POC-Hb testing, measurement of hemoglobin using POC-Hb has a sensitivity of 71.4% for detecting hemoconcentration compared to the traditional hematocrit criteria. Our findings support the use of POC-Hb testing adjunct with a complete blood count to guide fluid management in dengue patients.

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.

Molecular investigation of the dengue outbreak in Karnataka, South India, reveals co-circulation of all four dengue virus serotypes

The growing incidence of dengue outbreaks in the state of Karnataka prompted us to study the circulating dengue virus (DENV) and their proportion among the suspected cases of dengue patients during the disease outbreak at Mysuru district of Southern India. The presence of the DENV in a patient's serum sample was identified by RT-PCR using previously published primer pairs targeting CprM gene. DENV serotyping was carried out by semi-nested multiplex PCR using serotype-specific primers and nucleotide sequencing. Three hundred fifty-five samples of serum from suspected dengue cases were collected, and 203 samples (57.18%) were found positives. In 2016, DENV-4 (97.87%) was found to be the most dominant DENV serotype either alone or as co-infection, followed by DENV-2 (8.51%) and DENV-3 (4.25%). In 47 positive cases, co-infection with more than one serotype was detected in 4 cases (8.51%). The analysis of the dengue cases in 2017, DENV-4 was dominating serotype (33.97%), followed by the emergence of DENV-2 (32.05%), DENV-3 (25.64%), and DENV-1 (25.00%). Our study also reports the circulation of all four DENV serotypes in the Mysuru district of Southern India, with concurrent infections rate of 16.66% in 2017. The present study provides information regarding the genetic variation among the circulating DENV serotype in an Indian state of Karnataka. The need for the studying genetic diversity of DENV will be useful during the continuous monitoring for disease burden as well as the development of appropriate prophylactic measures to control the spread of dengue infection.

Investigation of the efficacy and safety of eltrombopag to correct thrombocytopenia in moderate to severe dengue patients - a phase II randomized controlled clinical trial

BACKGROUND

The dengue-infected patients with or without hemorrhagic manifestations, typically exhibit moderate to severe thrombocytopenia. A thrombopoietin receptor agonist - eltrombopag has been efficacious in correcting thrombocytopenia in patients with various pathological conditions including immune thrombocytopenia, chronic liver disease, and severe aplastic anemia. This study investigated the efficacy and safety of eltrombopag to correct dengue-mediated thrombocytopenia.

METHODS

In this open-label, randomized controlled phase-II trial, patients with dengue fever (DF) and dengue hemorrhagic fever (DHF) having platelet (PLT) count lower than 100 × 109/L without comorbidity, pregnancy, and liver abnormalities were enrolled in Dhaka Medical College Hospital, Better Life Hospital and AMZ hospital, Dhaka, Bangladesh. Between October 10, 2019, and December 30, 2019, 123 DF and DHF patients were assessed for eligibility to be enrolled in the trial. Fourteen patients were excluded as they failed to fulfill the inclusion criteria (N = 6) or refused to participate in the trial (N = 8). Finally, 109 patients were randomly assigned to either Group 1, (N = 36), Group 2 (N = 37), or Control-group (N = 36) in a 1:1:1 ratio. Two doses of eltrombopag - 25 mg/day and 50 mg/day were administered to Group-1 and Group-2 patients, respectively whereas the control-group patients received standard dengue treatment without eltrombopag. The management of all enrolled patients was according to WHO guidelines. The randomization procedure was performed by using a computerized system (STATA Inc.). CBC and immature platelet fraction (IPF) were monitored from Day-0 to Day-7. Absolute immature platelet count (A-IPC) was calculated from PLT count and IPF for each patient. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured on Day-0 and Day-4 and an Ultrasonogram (USG) of the abdomen was performed on Day-4 and Day-7 for each patient. The efficacy of eltrombopag as the primary outcome of the trial was investigated by the proportion of patients with recovered platelet count receiving eltrombopag with corrected platelet count (platelet count above the lower normal limit: 150 × 109/L) on Day-7 of the enrollment as compared to the Control-group. As the secondary outcomes, the reduction of bleeding tendency in response to eltrombopag as well as the safety of eltrombopag in dengue patients were assessed. The safety was evaluated in case of adverse events, liver function enzymes AST/ALT levels and USG. This trial is registered with the international clinical trial registry, number SLCTR/2019/037.

RESULTS

A total of 101 patients including 77 DF and 24 DHF patients completed the trial as eight patients left the trial without completing the follow-up. Patients of the different groups were compared with respect to mean age (26±8, 30±10 and 30±9 years for, Group-1,-2 and Control-group, respectively) (p-value= 0.23) and basal PLT count (Group-1: 58±24 × 109; Group-2: 52±29 × 109 and control-group: 55±30 × 109) (p-value= 0.63). The mean PLT counts for Group-1 (332 × 109/L ± 92) and Group-2 (371 × 109/L ± 111) were significantly higher than control-group (194 × 109/L ± 96) on Day-7 (adjusted p-value= 1.15 × 10-06 for Group-1 vs. Control-group, and adjusted p-value= 1.82 × 10-08 for Group-2 vs. Control-group).). On Day-7, 91% of Group-1 (N = 30) and Group-2 (N = 32) patients who received eltrombopag achieved primary endpoint of PLT count above than lower normal limit (150 × 109/L) (Group-1: 91%, OR: 8.33, 95% CI: 2.11 to 32.80, p-value: 0.0024 and Group-2: 91%, OR: 8.89, 95% CI: 2.26 to 34.89, p-value: 0.0017) compared to 55% (N = 18) of control-group patients who did not receive eltrombopag. The bleeding manifestations for thirteen out of fourteen grade-II DHF patients were subsided within Day-7 who received eltrombopag, whereas four out of ten grade-II DHF patients with PLT counts lower than the lower normal limit in the control group showed intermittent bleeding symptoms throughout the trial period. Mean A-IPC but not IPF was significantly higher for eltrombopag-treated groups in comparison to the Control-group. The frequency of the most common adverse events (vomiting and diarrheal tendencies) was similar in the treated-and control-groups (N = 5, 15%, and N = 3, 9% for Group-1 and -2, respectively vs. N = 4, 12% in the Control-group). Ten (30%) patients of Group-1 and, fourteen (40%) patients of Group-2 showed increased AST (U/L) as opposed to nine patients (27%) in the Control-group. Increased ALT levels were observed for three (9%), nine (26%), and seven (21%) patients belonging to the Group-1, -2, and Control-group, respectively. PLT counts higher than the upper normal limit (450 × 109/L) on Day-7 were observed for seven patients who were administered the higher dose (50 mg/day) in contrast to the three patients receiving the lower dose (25 mg/day). USG reports did not show thrombosis events in any of the patients.

INTERPRETATION

The trial revealed that the administration of eltrombopag in a short regimen for three days was efficacious to restore the PLT count in DF and DHF patients. The higher number of A-IPCs in eltrombopag treated patients underscored the possible mode of action of eltrombopag through stimulating megakaryopoiesis in dengue patients. The trial hints toward the positive effect of eltrombopag in the cessation of bleeding manifestation. Administration of the lower dose (25 mg/day) of eltrombopag was shown to be safer and equally efficacious to the higher dose (50 mg/day) in treating dengue-infected patients.

Impact of Nutritional Status on the Severity of Dengue Infection Among Pediatric Patients in Southern Thailand

BACKGROUND

Given the lack of specific antiviral drugs and effective vaccine for dengue infection, factors such as host nutritional status that may alter disease progression require investigation. This study examined the relationship between baseline nutritional status and severity of dengue infection in pediatric patients.

METHODS

Data from dengue patients 1-14 years of age treated at four hospitals in southern Thailand (2017-2018) were reviewed. Dengue infection was classified as dengue fever, dengue hemorrhagic fever and dengue shock syndrome. Children's nutritional status was assessed based on international and national growth charts. Binary logistic regression was used to identify factors associated with dengue severity and malnutrition.

RESULTS

Overall, 248, 281 and 43 patients had dengue fever, dengue hemorrhagic fever and dengue shock syndrome, respectively. Overweight was associated with increased risk of dengue severity [odds ratio (OR) = 1.76, 95% confidence interval (CI): 1.13-2.75, P = 0.012; OR = 1.84, 95% CI: 1.09-3.09, P = 0.022, per international and national growth criteria, respectively). Stunting was associated with decreased risk of dengue severity (OR = 0.54, 95% CI: 0.33-0.88, P = 0.013; OR = 0.61, 95% CI: 0.39-0.95, P = 0.030, per international and national growth criteria, respectively). Being overweight was significantly and positively associated with levels of hemoglobin >14 g/dL, hematocrit >42%, hemoconcentration ≥20% and platelet count ≤50,000/mm, whereas being stunted was significantly and negatively associated with levels of hemoglobin >14 g/dL and hematocrit >42%.

CONCLUSIONS

These findings support a hypothesis that malnutrition might influence the severity of dengue infection through host immune response. Overweight children with dengue infections should be closely observed for early signs of severe dengue infection.

Acute liver failure and death predictors in patients with dengue-induced severe hepatitis

BACKGROUND

Liver injury in patients with dengue infection is common. Most patients have mild and transient hepatitis. Acute liver failure (ALF) in dengue infection is rare but results in an extremely poor prognosis.

AIM

To identify prognostic predictors of ALF and death in patients with dengue-induced severe hepatitis (DISH).

METHODS

We retrospectively reviewed 2311 serologically confirmed adolescent and adult dengue patients who were hospitalized during a 12-year study period (between 2007 and 2019) at the university hospital of King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Patients with DISH [n = 134 (5.80%)], defined as a baseline transaminase > 10 times the normal reference cut-off level, and DISH with subsequent ALF as defined by the American Association for the Study of the Liver Diseases 2011 criteria [n = 17 (0.74%)], were included. Predictors of ALF and in-hospital death were identified using logistic regression analysis.

RESULTS

Of the 151 dengue-infected patients with severe liver injury or ALF, 51% were female, with a mean age of 27.9 ± 14.5 years. Capillary leakage syndrome (CLS) occurred in 68.2% (n = 103) of DISH and 100% of ALF patients. The mortality rate was low in DISH patients (0.8%) but was remarkably high if ALF developed (58.8%). In univariate analysis, age, sex, hematocrit, white blood count, atypical lymphocyte count, platelet count, international normalized ratio (INR), bilirubin, serum glutamate-oxaloacetate transaminase, serum glutamate-pyruvate transaminase, alkaline phosphatase, albumin, creatinine, Model for End-Stage Liver Disease (MELD) score, presence of liver comorbidity and presence of CLS were identified as potential prognostic parameters for ALF or death. In multivariate analysis, the MELD score remained the only predictor of ALF with an adjusted odds ratio (aOR) of 1.3 [95% confidence interval (CI): 1.1-1.5; P = < 0.001]. An initial MELD score ≥ 15 was associated with ALF from DISH with an area under the receiver operating characteristic (AUROC) of 0.91, 88.2% sensitivity and 87.3% specificity. Regarding mortality prediction, the deterioration of liver function to ALF was the most significant factor related to death in DISH patients (aOR 108.5, 95%CI: 5.5-2145.4, P = 0.002). Other independent factors associated with death included baseline INR (aOR 10.4, 95%CI: 2.6-40.5, P = 0.001). An INR ≥ 1.5 predicted death from DISH with an AUROC of 0.83 (81.8% sensitivity and 86.8% specificity).

CONCLUSION

The MELD score is the best predictor of ALF in DISH patients, a complication from dengue that is associated with high mortality. The presence of ALF and the baseline INR level are independent markers of death in DISH patients.

Crocetin Improves Dengue Virus-Induced Liver Injury

Dengue virus (DENV) infection is one of the most widespread mosquito-borne viral infections. Liver injury is commonly observed in severe DENV infection, and the present study aimed to examine the efficacy of crocetin treatment in an immunocompetent mouse model of DENV infection exhibiting liver injury. The efficacy of crocetin treatment in DENV-induced liver injury was assessed via both transaminase levels and histopathology analysis. A real-time polymerase chain reaction array was then used to describe the expression of 84 apoptosis-related genes. Using real-time RT-PCR and Western blot analysis, the gene expressions of host factors were investigated. Additionally, the effect of crocetin in NF-kB signaling during DENV infection was studied. We did not observe any significant reduction in virus production when DENV-infected mice were treated with crocetin. However, DENV-infected mice treated with crocetin showed reduced DENV-induced apoptosis. The real-time polymerase chain reaction array revealed pro-inflammatory cytokine expressions to be significantly reduced in the crocetin-treated DENV-infected mice. We also found that crocetin could effectively modulate antioxidant status in DENV-infected mice. Moreover, crocetin demonstrated the ability to reduce the nuclear translocation of NF-kB in DENV-infected mice. Our results suggest that crocetin treatment does not inhibit DENV replication in the liver of DENV-infected mice; however, we did find that crocetin improves host responses that reduce liver injury.

The clinical profile, hematological parameters and liver transaminases of dengue NS1 Ag positive patients admitted to Jaffna Teaching Hospital, Sri Lanka

Objective

Objective of the study is to evaluate the on-admission day symptoms and signs, clinical, hematological parameters and liver transaminases of the dengue NS1 positive patients who got admitted on different clinical phases [Febrile phase (day 1–3) and Critical phase(day 4–5)] of dengue at medical wards of Jaffna Teaching Hospital.

Results

Blood samples were collected from 150 suspected dengue patients from day 1 to 5 of the illness. Seventy-eight patients were positive for dengue NS1, according to the WHO proposed dengue clinical phase framework 37 patients were from febrile phase and 41 patients from critical phase. Patients who admitted on critical phase framework suffered from leukopenia and thrombocytopenia. Nine patients had the evidence of leakage with fever and the leakers had significant rise in hemoglobin, hematocrit and liver transaminase levels which are considered as severe form of the disease.