Simple Prognostic Criteria can Definitively Identify Patients who Develop Severe Versus Non-Severe Dengue Disease, or Have Other Febrile Illnesses

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

Background

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

Methods

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

Results

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

Conclusions

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

Supplementary Information

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

Evaluation of the National Case Report Form for dengue and timely case notification before the co-circulation of multiple arboviruses in Barranquilla, Colombia

OBJECTIVE

To evaluate the case report forms and times elapsed between the surveillance steps for dengue virus (DENV) infection in a large Colombian city before the emergence of other arbovirus epidemics.

MATERIALS AND METHODS

The descriptive epidemiology of DENV infection cases was analyzed from 2009 to 2013. The completeness of the case report forms filed at the Primary Units of Data Generation (PUDG) were evaluated, as well as the accuracy and suitability of the tests (PPV: positive predictive value). The average time-lags between each step were then calculated.

RESULTS

There were 7.3, 12.38, 4.66, 6.25 and 29.9 annual cases of dengue infection per 10 000 inhabitants in 2009 to 2013, respectively. In this study, only 57.76% of the cases were classified correctly by the physicians and 26.32% of them were questioned about their home conditions and whether their family/friends had similar symptoms. Patients visited a clinic/hospital on average 4.76 days after developing symptoms and the health system was notified on average 1.75 days later, while 70.6% of them were reported within the one-day target period. There were only minor changes in case reporting times even during a DENV epidemic. Some (12.85%) of the case forms were later modified (average 16.7 days). In the period 2009-2013, the IgM confirmed PPV was 58.60%, while 20 mandatory criteria were absent on more than 25% of the forms.

CONCLUSIONS

The system was accurate, simple, flexible, stable and acceptable, but a number of ways are suggested to improve this case detection and reporting system.

Dengue epidemic in a non-endemic zone of Bangladesh: Clinical and laboratory profiles of patients

BACKGROUNDS

Approximately, half of the population in the world including tropical and sub-tropical climates region is at risk of dengue. Being an endemic country, Bangladesh has experienced the largest dengue epidemic in 2019. The present study aimed at evaluating the clinical and laboratory profile of dengue patients in northern Bangladesh during the epidemic.

METHODS

This cross-sectional study included 319 serologically confirmed dengue patients admitted in Shaheed Ziaur Rahman Medical College Hospital in Bogra district. It is one of the main tertiary care hospitals in northern Bangladesh. Data were collected from July to September 2019. Patients' clinical and laboratory data were extracted from clinical records. Patients were classified into two classes according to the WHO 2009 dengue classification such as (i) non-severe dengue and (ii) severe dengue. Chi-square test and independent t-test were used in this study.

RESULTS

Of the 319 patients, 94.1% had non-severe dengue and the remaining 5.9% had severe dengue (severe plasma leakage 68.4%, severe organ involvement 68.4%, and severe clinical bleeding 10.5%). Most of the patients were suffering from primary dengue infection. The most common clinical presentation was fever followed by headache and myalgia. Vomiting and abdominal pain were the most prevalent warning signs. The common hematological findings on admission were leukopenia (63.3%), thrombocytopenia (30.4%) and increased hematocrit (26.6%). Raised serum ALT or AST was observed in 14.1% cases whereas raised serum creatinine was observed in 6.6% cases. Signs of plasma leakage (pleural effusion, respiratory distress, and ascites, rise of hematocrit >20% during hospital stay) and hepatic or renal involvement (serum ALT >42UI/L or serum creatinine >1.2 mg/dL) on admission were mostly associated with severe dengue.

CONCLUSION

The study provides clinical evidence on presentation as well as hematological and biochemical profile of dengue patients in northern Bangladesh that should be implicated in effective patient management.

Spatiotemporal Heterogeneity in the Distribution of Chikungunya and Zika Virus Case Incidences during their 2014 to 2016 Epidemics in Barranquilla, Colombia

Chikungunya virus (CHIKV) and Zika virus (ZIKV) have recently emerged as globally important infections. This study aimed to explore the spatiotemporal heterogeneity in the occurrence of CHIKV and ZIKV outbreaks throughout the major international seaport city of Barranquilla, Colombia in 2014 and 2016 and the potential for clustering. Incidence data were fitted using multiple Bayesian Poisson models based on multiple explanatory variables as potential risk factors identified from other studies and options for random effects. A best fit model was used to analyse their case incidence risks and identify any risk factors during their epidemics. Neighbourhoods in the northern region were hotspots for both CHIKV and ZIKV outbreaks. Additional hotspots occurred in the southwestern and some eastern/southeastern areas during their outbreaks containing part of, or immediately adjacent to, the major circular city road with its import/export cargo warehouses and harbour area. Multivariate conditional autoregressive models strongly identified higher socioeconomic strata and living in a neighbourhood near a major road as risk factors for ZIKV case incidences. These findings will help to appropriately focus vector control efforts but also challenge the belief that these infections are driven by social vulnerability and merit further study both in Barranquilla and throughout the world's tropical and subtropical regions.

An Evidence-Based Algorithm for Early Prognosis of Severe Dengue in the Outpatient Setting

Background

Early prediction of severe dengue could significantly assist patient triage and case management.

Methods

We prospectively investigated 7563 children with ≤3 days of fever recruited in the outpatient departments of 6 hospitals in southern Vietnam between 2010 and 2013. The primary endpoint of interest was severe dengue (2009 World Health Organization Guidelines), and predefined risk variables were collected at the time of enrollment to enable prognostic model development.

Results

The analysis population comprised 7544 patients, of whom 2060 (27.3%) had laboratory-confirmed dengue; nested among these were 117 (1.5%) severe cases. In the multivariate logistic model, a history of vomiting, lower platelet count, elevated aspartate aminotransferase (AST) level, positivity in the nonstructural protein 1 (NS1) rapid test, and viremia magnitude were all independently associated with severe dengue. The final prognostic model (Early Severe Dengue Identifier [ESDI]) included history of vomiting, platelet count, AST level. and NS1 rapid test status.

Conclusions

The ESDI had acceptable performance features (area under the curve = 0.95, sensitivity 87% (95% confidence interval [CI], 80%-92%), specificity 88% (95% CI, 87%-89%), positive predictive value 10% (95% CI, 9%-12%), and negative predictive value of 99% (95% CI, 98%-100%) in the population of all 7563 enrolled children. A score chart, for routine clinical use, was derived from the prognostic model and could improve triage and management of children presenting with fever in dengue-endemic areas.

Tourniquet Test for Dengue Diagnosis: Systematic Review and Meta-analysis of Diagnostic Test Accuracy

BACKGROUND

Dengue fever is a ubiquitous arboviral infection in tropical and sub-tropical regions, whose incidence has increased over recent decades. In the absence of a rapid point of care test, the clinical diagnosis of dengue is complex. The World Health Organisation has outlined diagnostic criteria for making the diagnosis of dengue infection, which includes the use of the tourniquet test (TT).

PURPOSE

To assess the quality of the evidence supporting the use of the TT and perform a diagnostic accuracy meta-analysis comparing the TT to antibody response measured by ELISA.

DATA SOURCES

A comprehensive literature search was conducted in the following databases to April, 2016: MEDLINE (PubMed), EMBASE, Cochrane Central Register of Controlled Trials, BIOSIS, Web of Science, SCOPUS.

STUDY SELECTION

Studies comparing the diagnostic accuracy of the tourniquet test with ELISA for the diagnosis of dengue were included.

DATA EXTRACTION

Two independent authors extracted data using a standardized form.

DATA SYNTHESIS

A total of 16 studies with 28,739 participants were included in the meta-analysis. Pooled sensitivity for dengue diagnosis by TT was 58% (95% Confidence Interval (CI), 43%-71%) and the specificity was 71% (95% CI, 60%-80%). In the subgroup analysis sensitivity for non-severe dengue diagnosis was 55% (95% CI, 52%-59%) and the specificity was 63% (95% CI, 60%-66%), whilst sensitivity for dengue hemorrhagic fever diagnosis was 62% (95% CI, 53%-71%) and the specificity was 60% (95% CI, 48%-70%). Receiver-operator characteristics demonstrated a test accuracy (AUC) of 0.70 (95% CI, 0.66-0.74).

CONCLUSION

The tourniquet test is widely used in resource poor settings despite currently available evidence demonstrating only a marginal benefit in making a diagnosis of dengue infection alone.

REGISTRATION

The protocol for this systematic review was registered at

PROSPERO

CRD42015020323.

Predictive tools for severe dengue conforming to World Health Organization 2009 criteria

Background

Dengue causes 50 million infections per year, posing a large disease and economic burden in tropical and subtropical regions. Only a proportion of dengue cases require hospitalization, and predictive tools to triage dengue patients at greater risk of complications may optimize usage of limited healthcare resources. For severe dengue (SD), proposed by the World Health Organization (WHO) 2009 dengue guidelines, predictive tools are lacking.

Methods

We undertook a retrospective study of adult dengue patients in Tan Tock Seng Hospital, Singapore, from 2006 to 2008. Demographic, clinical and laboratory variables at presentation from dengue polymerase chain reaction-positive and serology-positive patients were used to predict the development of SD after hospitalization using generalized linear models (GLMs).

Principal findings

Predictive tools compatible with well-resourced and resource-limited settings – not requiring laboratory measurements – performed acceptably with optimism-corrected specificities of 29% and 27% respectively for 90% sensitivity. Higher risk of severe dengue (SD) was associated with female gender, lower than normal hematocrit level, abdominal distension, vomiting and fever on admission. Lower risk of SD was associated with more years of age (in a cohort with an interquartile range of 27–47 years of age), leucopenia and fever duration on admission. Among the warning signs proposed by WHO 2009, we found support for abdominal pain or tenderness and vomiting as predictors of combined forms of SD.

Conclusions

The application of these predictive tools in the clinical setting may reduce unnecessary admissions by 19% allowing the allocation of scarce public health resources to patients according to the severity of outcomes.

Dengue is a mosquito-borne tropical disease that poses a large economic and health burden to 40% of the world's population. Some dengue patients can evolve into a more severe form of the illness (severe dengue) and ideally should be hospitalized when this occurs. However, while only a small proportion of patients have severe dengue, many other patients are unnecessarily hospitalized. Being able to identify those patients at the highest risk of developing severe dengue can be very useful to reduce costs to hospitals and patients. In this study, we develop predictive tools to identify those patients that should be hospitalized. We find that some common features such as age, gender, fever duration, fever on admission, vomiting or abdominal distension can be good predictors of severe dengue. This is important because these features are easy to identify even in resource-limited settings where laboratory tests are not widely available.

Predictive symptoms and signs of severe dengue disease for patients with dengue fever: a meta-analysis

The aim of the meta-analysis was to provide more solid evidence for the reliability of the new classification. A systematic literature search was performed using PubMed, Armed Forces Pest Management Board Literature Retrieval System, and Google Scholar up to August 2012. A pooled odds ratio (OR) was calculated using either a random-effect or a fixed-effect model. A total of 16 papers were identified. Among the 11 factors studied, five symptoms demonstrated an increased risk for SDD, including bleeding [OR: 13.617; 95% confidence interval (CI): 3.281, 56.508], vomiting/nausea (OR: 1.692; 95% CI: 1.256, 2.280), abdominal pain (OR: 2.278; 95% CI: 1.631, 3.182), skin rashes (OR: 2.031; 95% CI: 1.269, 3.250), and hepatomegaly (OR: 4.751; 95% CI: 1.769, 12.570). Among the four bleeding-related symptoms including hematemesis, melena, gum bleeding, and epistaxis, only hematemesis (OR: 6.174; 95% CI: 2.66, 14.334; P < 0.001) and melena (OR: 10.351; 95% CI: 3.065, 34.956; P < 0.001) were significantly associated with SDD. No significant associations with SDD were found for gender, lethargy, retroorbital pain, diarrhea, or tourniquet test, whereas headache appeared protective (OR: 0.555; 95% CI: 0.455, 0.676). The meta-analysis suggests that bleeding (hematemesis/melena), vomiting/nausea, abdominal pain, skin rashes, and hepatomegaly may predict the development of SDD in patients with DF, while headache may predict otherwise.

Significantly lower anti-Leishmania IgG responses in Sudanese versus Indian visceral leishmaniasis

BACKGROUND

Visceral leishmaniasis (VL), a widely distributed systemic disease caused by infection with the Leishmania donovani complex (L. donovani and L. infantum), is almost always fatal if symptomatic and untreated. A rapid point-of-care diagnostic test for anti-Leishmania antibodies, the rK39-immunochromatographic test (rK39-ICT), has high sensitivity and specificity in South Asia but is less sensitive in East Africa. One of the underlying reasons may be continent-specific molecular diversity in the rK39 antigen within the L. donovani complex. However, a second reason may be differences in specific IgG anti-Leishmania levels in patients from different geographical regions, either due to variable antigenicity or immunological response.

METHODOLOGY/PRINCIPAL FINDINGS

We determined IgG titres of Indian and Sudanese VL patients against whole cell lysates of Indian and Sudanese L. donovani strains. Indian VL patients had significantly higher IgG titres against both L. donovani strains compared to Sudanese VL patients (p<0.0001). Mean reciprocal log10 50% end-point titres (1/log10t50) were i) 3.80 and 3.88 for Indian plasma and ii) 2.13 and 2.09 for Sudanese plasma against Indian and Sudanese antigen respectively (p<0.0001). Overall, the Indian VL patients therefore showed a 46.8-61.7 -fold higher mean ELISA titre than the Sudanese VL patients. The higher IgG titres occurred in children (<16 years old) and adults of either sex from India (mean 1/log10t50: 3.60-4.15) versus Sudan (mean 1/log10t50: 1.88-2.54). The greatest difference in IgG responses was between male Indian and Sudanese VL patients of ≥ 16 years old (mean 1/log10t50: 4.15 versus 1.99 = 144-fold (p<0.0001).

CONCLUSIONS/SIGNIFICANCE

Anti-Leishmania IgG responses among VL patients in Sudan were significantly lower than in India; this may be due to chronic malnutrition with Zn(2+) deficiency, or variable antigenicity and capacity to generate IgG responses to Leishmania antigens. Such differential anti-Leishmania IgG levels may contribute to lower sensitivity of the rK39-ICT in East Africa.

Development of dengue infection severity score

Objectives. To develop a simple scoring system to predict dengue infection severity based on patient characteristics and routine clinical profiles. Methods. Retrospective data of children with dengue infection from 3 general hospitals in Thailand were reviewed. Dengue infection was categorized into 3 severity levels: dengue infection (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Coefficients of significant predictors of disease severity under ordinal regression analysis were transformed into item scores. Total scores were used to classify patients into 3 severity levels. Results. Significant clinical predictors of dengue infection severity were age >6 years, hepatomegaly, hematocrit ≥40%, systolic pressure <90 mmHg, white cell count >5000 / μ L, and platelet ≤50000 / μ L. The derived total scores, which ranged from 0 to 18, classified patients into 3 severity levels: DF (scores <2.5, n = 451, 58.1%), DHF (scores 2.5-11.5, n = 276, 35.5%), and DSS (scores >11.5, n = 50, 6.4%). The derived score correctly classified patients into their original severity levels in 60.7%. An under-estimation of 25.7% and an over-estimation of 13.5% were clinically acceptable. Conclusions. The derived dengue infection severity score classified patients into DF, DHF, or DSS, correctly into their original severity levels. Validation of the score should be reconfirmed before application of routine practice.

A simple, inexpensive, robust and sensitive dot-blot assay for equal detection of the nonstructural-1 glycoprotein of all dengue virus serotypes

Background

Detection of dengue virus (DENV) soluble/excreted (s/e) form of the nonstructural-1 (NS1) glycoprotein in patient acute-phase sera is ideal for diagnosis. The commercially-available detection assays are, however, too expensive for routine use and have low specificity, particularly for the s/e NS1 glycoprotein of DENV-2 and DENV-4, which are important causes of lethal human disease worldwide.

Methods

Mouse monoclonal antibodies (MAbs) were generated and screened against s/e NS1 glycoprotein purified from each DENV serotype to obtain those that reacted equally with each serotype, but not with yellow fever virus (YFV) s/e NS1 glycoprotein or human serum proteins. One MAb, MAb 2C4.6, was further tested against these DENV glycoproteins in human sera using simple, peroxidase-labelled secondary antibody/substrate-developed dot-blot assays.

Results

Optimal quenching of endogenous human serum peroxidases was attained using 3% H₂O₂ in H₂0 for 5 min. MAb 2C4.6 showed an acceptable detection sensitivity of < 32 ng/ml for the s/e NS1 glycoprotein of each DENV serotype but did not cross-react with the YFV s/e NS1 glycoprotein or human serum proteins. By contrast, the LX1 epitope-specific MAb, 3D1.4, showed similar detection sensitivity against only the DENV-1 NS1 glycoprotein, consistent with results from commercial DENV s/e NS1 glycoprotein detection assays.

DENV s/e NS1 glycoproteins were stable in human sera after drying on the nitrocellulose membranes and storage for one month at ambient temperature (28°C) before being processed. The total assay time was reduced to 3 h without any loss of detection sensitivity. This dot-blot format was ideal for the circulating immune complex disruption step, which is required for increased DENV s/e NS1 glycoprotein detection.

Conclusions

This is the first study to determine the detection sensitivity of MAbs against known concentrations of s/e NS1 glycoprotein from each DENV serotype. The preparation of patient serum samples for dot-blot assays can be performed by staff with a basic level of training and storage at low temperatures (e.g., -80°C) is not necessary. These simple, inexpensive (US$ 0.05/sample), robust, sensitive and relatively rapid assays, using improved MAbs such as MAb 2C4.6, should be ideal for the diagnosis of all DENV serotypes in DENV endemic regions.

Epitope reactions can be gauged by relative antibody discriminating specificity (RADS) values supported by deletion, substitution and cysteine bridge formation analyses: potential uses in pathogenesis studies

Background

Epitope-mapping of infectious agents is essential for pathogenesis studies. Since polyclonal antibodies (PAbs) and monoclonal antibodies (MAbs) are always polyspecific and can react with multiple epitopes, it is important to distinguish between specific and non-specific reactions. Relative antibody discriminating specificity (RADS) values, obtained from their relative ELISA reactions with L-amino acid peptides prepared in the natural versus reverse orientations (x-fold absorbance natural/absorbance reverse = RADS value) may be valuable for this purpose.

PAbs generated against the dengue type-2 virus (DENV-2) nonstructural-1 (NS1) glycoprotein candidate vaccine also reacted with both DENV envelope (E) glycoproteins and blood-clotting proteins. New xKGSx/xSGKx amino acid motifs were identified on DENV-2 glycoproteins, HIV-1 gp41 and factor IXa. Their potential roles in DENV and HIV-1 antibody-enhanced replication (AER) and auto-immunity were assessed.

In this study, a) RADS values were determined for MAbs and PAbs, generated in congeneic (H2: class II) mice against DENV NS1 glycoprotein epitopes, to account for their cross-reaction patterns, and b) MAb 1G5.3 reactions with xKGSx/xSGKx motifs present in the DENV-4 NS1, E and HIV-1 glycoproteins and factor IXa were assessed after the introduction of amino acid substitutions, deletions, or intra-/inter-cysteine (C-C) bridges.

Results

MAbs 1H7.4, 5H4.3, 3D1.4 and 1G5.3 had high (4.23- to 16.83-fold) RADS values against single epitopes on the DENV-2 NS1 glycoprotein, and MAb 3D1.4 defined the DENV complex-conserved LX1 epitope. In contrast, MAbs 1G5.4-A1-C3 and 1C6.3 had low (0.47- to 1.67-fold) RADS values against multiple epitopes. PAb DENV complex-reactions occurred through moderately-high (2.77- and 3.11-fold) RADS values against the LX1 epitope. MAb 1G5.3 reacted with xSGKx motifs present in DENV-4 NS1 and E glycoproteins, HIV-1 gp41 and factor IXa, while natural C-C bridge formations or certain amino acid substitutions increased its binding activity.

Conclusions

These results: i) were readily obtained using a standard 96-well ELISA format, ii) showed the LX1 epitope to be the immuno-dominant DENV complex determinant in the NS1 glycoprotein, iii) supported an antigenic co-evolution of the DENV NS1 and E glycoproteins, and iv) identified methods that made it possible to determine the role of anti-DENV PAb reactions in viral pathogenesis.