NS1 Positivity Research Articles

Gallbladder Wall Thickening for Early Detection of Plasma Leakage Among Children with Dengue Fever Admitted in a Tertiary Care Hospital

Background: Plasma leakage is defined as e”20% elevation of hematocrit from baseline or evidence of plasma leakages such as pleural effusion, ascites, or hypoalbuminemia. In the early phase, these signs of plasma leakage are usually difficult to ascertain by physical examination and laboratory tests. Objective: This study aimed to investigate whether gallbladder wall thickening (GBWT) in the febrile phase of the disease can be used to detect the occurrence of plasma leakage in dengue patients. Methods: A cross-sectional analytical study was conducted during a 4-month period in Dr. M R Khan Shishu Hospital and ICH from September 2021 to December 2021. Children from 6 months to 14 years who were admitted with acute onset of fever less than 3 days with NS1 positivity were included consecutively. Laboratory tests and abdominal Ultrasonography were also performed to confirm the occurrence of plasma leakage. Result: Out of 114 patients, the majority were male (64%), in the 5-<10-year age group(48.25%). Common presentations include fever (100%), flushed appearance (66.7%), abdominal pain (66.7%), vomiting (44.7%), bodyache (39.5%), During the febrile phase, 56patients were presented with GBWT, 49 of which showed plasma leakage during treatment. The sensitivity and specificity of GBWT during fever were 89% and 88%. PPV and NPV were 87% and 90% respectively. In risk factor analysis, Gallbladder wall thickening was found statistically significant (<.009) predictor of plasma leakage in dengue. Conclusion: Gallbladder wall thickening during the febrile phaseis a predictor of plasma leakage in Dengue. BANGLADESH J CHILD HEALTH 2022; VOL 46 (3) : 138-143

Geographic information system-aided evaluation of epidemiological trends of dengue serotypes in West Bengal, India.

West Bengal is a dengue-endemic State in India, with all four dengue serotypes in co-circulation. The present study was conceived to determine the changing trends of circulating dengue virus (DENV) serotypes in five consecutive years (2015-2019) using a geographic information system (GIS) during the dengue season in West Bengal, India. Molecular serotyping of dengue NS1 sero-reactive serum samples from individuals with ≤5 days of fever was performed using conventional nested reverse transcriptase-PCR. GIS techniques such as Getis-Ord Gi* hotspot analysis and heatmap were used to elucidate dengue transmission based on the received NS1-positive cases and vector data analysis was used to point out risk-prone areas. A total of 3915 dengue NS1 sero-positive samples were processed from most parts of West Bengal and among these, 3249 showed RNA positivity. The major circulating serotypes were DENV 3 (63.54%) in 2015, DENV 1 (52.79%) in 2016 and DENV 2 (73.47, 76.04 and 47.15%) in 2017, 2018 and 2019, respectively. Based on the NS1 positivity, dengue infections were higher in males than females and young adults of 21-30 yr were mostly infected. Getis-Ord Gi* hotspot cluster analysis and heatmap indicate that Kolkata has become a hotspot for dengue outbreaks and serotype plotting on maps confirms a changing trend of predominant serotypes during 2015-2019 in West Bengal. Co-circulation of all the four dengue serotypes was observed in this study, but only one serotype became prevalent during an outbreak. Representation of NS1-positive cases and serotype distribution in GIS mapping clearly showed serotypic shift in co-circulation. The findings of this study suggest the need for stringent surveillance in dengue-endemic areas to limit the impact of dengue and implement better vector-control strategies.

English

BACKGROUND Dengue fever is expanding in newer areas globally, with greater morbidity and mortality. We wanted to determine the proportion of bleeding manifestations among the confirmed dengue fever patients and evaluate the clinical outcomes in those with bleeding manifestations. METHODS 230 Dengue confirmed patients admitted in Government Medical College, Ernakulam from January 2018 to December 2018 were enrolled for the study. Data was recorded and entered in Microsoft Excel, and analysed using SPSS. RESULTS In the current study out of 230 subjects, bleeding manifestations were more common in 21 - 30 & 41 - 50 age groups. Out of 230 subjects, 102 had bleeding manifestations (44.3 %) like petechiae (34 %), purpura (24 %), echymosis (19.1 %), gum bleeding (17.8 %), menorrhagia (10.9 %), melena (10.4 %), conjunctival haemorrhage (9.1 %), haematuria (4.8 %), epistaxis (3.5 %), haemoptysis (2.2 %) and hematemesis (0.9 %). 86 subjects (37.4 %) received platelet transfusion on an average of 4 units. Age group, fever, previous history of dengue, IgG positivity, NS1 positivity were significantly (P < 0.0001) associated with bleeding. Most of the bleeding manifestations were significant in patients who had lower platelet counts on the first day of admission when it was less than ten thousand. CONCLUSIONS 44.3 % had bleeding manifestations with significant association between age, fever and IgG positivity. A low platelet count on admission especially less than 10,000 was significantly associated with these bleeding manifestations. These significant observations are important for both the primary care and tertiary care physicians in meticulous management and referral of dengue patients. KEY WORDS Dengue Fever, Bleeding Manifestations, Ns1 Antigen, Platelet Count.

Triple positivity for nonstructural antigen 1, immunoglobulin M and immunoglobulin G is predictive of severe thrombocytopaenia related to dengue infection.

The early identification of patients at risk of severe dengue infection (DI) is critical to guide clinical management. Non-structural antigen 1 (NS-1), immunoglobulin M (IgM) and immunoglobulin G (IgG) are used routinely for the diagnosis of DI. We sought to evaluate whether positivity for NS-1, IgM and IgG individually or together is predictive of severe complications of DI. A prospective study was conducted among patients with DI admitted to our institution between 2014 and 2019. DI was diagnosed based on a positive NS1 or IgM. IgG was also tested on all the patients. Clinical data was obtained from electronic medical records at NH. Statistical analyses were performed using SPSS version 20. We collected data on 3504 patients. Patients who were positive for NS1, IgM and IgG (triple positive: TP) were more likely to develop severe DI (63.8 %) in comparison to those who were only NS1 positive (single positive: SP) (3.0 %) and patients with positive NS1 and IgM (double positive: DP) (7.5 %). [p = 0.001]. Regression analysis confirmed that TP status on admission was predictive of severe complications. (p < 0.01). Receiver operator characteristic curve (ROC) analysis showed (AUC: 84.8; sensitivity = 90.7 and specificity = 83.2) that TP status on admission is predictive of thrombocytopenia on day 5. The predictive power of TP status was superior to that of NS1 and IgG positivity. We propose that TP status on admission is a novel predictive factor for severe DI. Further studies are required to explore the biological basis for this finding.

Correlation of clinical outcome with laboratory parameters in children with dengue infection: An appraisal from a tertiary children’s hospital in India

Introduction: Dengue infection is caused by the dengue virus (arbovirus), the incidence of which is increasing in India. In dengue endemic settings, early diagnosis and monitoring for complications are important, especially in children. Concurrent testing of NSI antigen, dengue specific IgG and IgM will help to diagnose patients with suspected dengue fever. Objective: To correlate the clinical profile and outcome of dengue fever with detection of NSI antigen, dengue specific IgG and IgM antibody, hematological and biochemical parameters and blood component utilization. Methods: All children presenting to Rainbow hospital and diagnosed with dengue infection using NS1 and dengue specific IgG and IgM antibody during a one year period (1st November 2016 to 31st October 2017) were included in the study. The haemogram and biochemistry parameters were done using automated analyzers. Inpatients were classified as severe or non-severe based on clinical and/or laboratory evidence. The degree of association between clinical parameters and disease severity in relation to NS1 positivity was expressed as an odds ratio. Results: Among 213 children diagnosed, 126 were treated as inpatients and the rest as outpatients. The age range of the study sample was 6 months to 15 years. NS1 positivity was observed in 72.3 % patients. NS1 positivity, when compared to severity of disease was significant (Odds ratio: 2.3; p Conclusions: Using all three tests (NS1, dengue specific IgM and IgG) was useful, as in 59 (27.7%) patients, despite a negative NS1, based on a positive dengue antibody response (IgG and/or IgM), the patients were admitted and monitored. NS1 positivity was associated with a higher risk of thrombocytopenia in this study.

Meningoencephalitis: Rare manifestation of Dengue haemorrhagic fever

Dengue is a common tropical disease occurring in Sri Lanka. Neurological manifestations due to dengue are very rare but can be caused by serotypes 2 and 3. Here we present a patient with meningoencephalitis occurring as a manifestation of dengue haemorrhagic fever (DHF) in a young boy who presented with fever, constitutional symptoms and a seizure. Diagnosis was confirmed by NS1 positivity and the presence of dengue specific IgM in the CSF with characteristic electroencephalographic findings. He was treated according to the dengue local national guidelines and had complete recovery without residual neurological deficits.

Clinical relevance of gallbladder wall thickening for dengue severity: A cross-sectional study.

Dengue fever is the most important arthropod-borne viral infection worldwide. Secondary prevention to reduce mortality through improved clinical case management has substantially lowered the mortality rate for severe dengue during the past two decades. Gallbladder wall thickening (GBWT) is a nonspecific finding often associated with more severe cases of dengue infection. This study had the aim to describe the ultrasonographic findings in hospitalized patients with dengue infection from Manaus (in the Western Brazilian Amazon) and to correlate the GBWT with dengue severity, symptoms and laboratorial analysis. Patients from 13–84 years admitted to the emergency department at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD) were enrolled in this study. Patients’ selection occurred during the most recent and huge dengue outbreak within the first semester of 2011. All enrolled subjects were systematically tested in order to rule out other possible etiologies for gallbladder inflammation. Abdominal ultrasound was performed by a single physician through bedside portable equipment and all other clinical and laboratorial information were retrieved from patients’ electronic files. 54 subjects were considered for analysis, with confirmed dengue infection by NS1 and/or RT-PCR positivity. From all enrolled patients, 50 (42.4%) presented GBWT. GBWT was significantly and independently related to: age under 31 years, pregnancy, presence of bleeding, presence of any cavitary effusion, DHF classification and severe dengue classifications. During dengue outbreaks, the GBWT identification through a non-invasive and bedside procedure is a confident marker for prompt recognition of potential severe cases.

Utility of NS1 antigen as an early serological marker in the diagnosis of dengue

Introduction: Dengue infection is one of the most common arboviral infection in India transmitted by the aedes mosquitoes. Early diagnosis of the infection is often missed if only the antibodies are tested. In this scenario detection of the NS1 antigen has gained importance which has very high specificity and can be detected from the first day of fever. Rapid immunochromatographic tests for the detection of both NS1 antigen as well as the IgM and IgG antibodies have been extensively used in the diagnosis of dengue infection because of the ease of performing when compared to ELISA testing. The present study aims in identifying various dengue markers in the early diagnosis of dengue fever. Materials and Methods: All the suspected dengue samples obtained in the Department of Microbiology were tested by rapid immunochromatography test for the detection of NS1 and IgM/IgG antibodies. Platelet counts were detected by automated analyzer and history and duration of fever has been taken. Results: A total of 1021 samples were tested for dengue infection out of which 158(15.4%) were positive for one or more of the dengue serology markers. Out of the 158, 85(53.79%) were positive only for NS1 antigen indicating the infection in the early stage, 60(37.97%) samples showed only IgM dengue antibodies and 6(3.79%) samples showed only IgG antibodies. Two serological markers are seen in 7 samples, out of which 4(2.53%) samples were positive for NS1+ IgM antibodies and the remaining 3(1.89%) samples for IgM+IgG antibodies. Majority of the cases were in the age group of 16-30 years and males were predominantly affected when compared to females. Decreased platelet count was observed in 62 out of 158 cases (39.2%). Maximum NS1 positivity was observed form 2nd to 7th day of fever where as IgM positivity was maximum between 7th to 9th day. Conclusion: Early diagnosis of dengue infection is warranted by the detection of NS1 antigen. Detection of NS1 antigen along with the IgM/IgG will ide

Clinical Profiles of Dengue Fever Patients, During an Outbreak

Dengue fever (DF) has become a major public health concern globally. It is an infection caused by a virus of the family Flaviviridae, with five serotypes (DENV 1-5). Recent years have seen an increase in the prevalence of the disease in Pakistan. The current study was carried out to evaluate the clinical features, laboratory findings and demographic information of the patients reported during the dengue outbreak in Multan of Pakistan in 2015. The hospital documentation-based data of confirmed DF cases were collected for the 6 months period from a Tertiary Care Hospital in Multan, Pakistan. The patients were labeled as confirmed on the basis of NS1 and IgM positivity by ELISA. The data collected were analyzed using SPSS. Overall, 361 patients were investigated (78.67% males and 21.33% females), with maximum infection rate in the age group of 18-35yr (50.41%). Mean hospital stay was 2.64d (SD 1.2), while mean fever duration was 5.27 (SD 1.57). Outbreak occurred during the months from Jul-Dec, while maximum patients were reported in Oct (287). No mortality was reported, and all patients recovered. Better management practices and timely reporting can reduce the risk factors associated with the disease.

Incidence and outcomes of dengue in a cohort of pregnant women from an endemic region of India: obesity could be a potential risk for adverse outcomes.

The primary objectives of the study were to determine the incidence of dengue and outcomes associated with dengue among pregnant women. A prospective cohort study was done among 1579 antenatal women in an endemic region in India. Dengue immunoglobulin G (IgG) was tested in 490 women at baseline. Follow-up phone calls and visits were done until 1 week after delivery. In 70 seronegative women, dengue IgG was repeated to identify seroconversion. Incidence proportions, incidence rates, relative risks, attributable risks and population attributable risks along with their 95% confidence intervals (CIs) were calculated. Propensity score methods were used for multivariate assessment of confounding and analysis was repeated with a matched dataset. The seroprevalence of dengue was 30.41% (95% CI 26.45 to 34.59). NS1 positivity detected 78% of dengue in pregnancy. There were no abortions or maternal or newborn deaths. Dengue was significantly associated with delivery complications (adjusted odds ratio [OR] 10.28 [95% CI 4.79 to 22.01]), newborn problems (adjusted OR 5.29 [95% CI 2.89 to 9.70]) and newborn admissions (adjusted OR 5.24 [95% CI 2.36 to 11.65]). Overweight dengue patients had a significantly higher risk of preterm deliveries and higher adverse outcome scores. Screening of febrile antenatal women for dengue in endemic areas can result in early diagnosis and reduce complications. The dual burden of communicable and non-communicable diseases in pregnancy is a real challenge.

A study of clinical and laboratory profiles of dengue fever in children

Background: Early recognition of characteristic clinical and laboratory parameters of is importantto facilitate prompt diagnosis andtreatmentfor a better outcome, particularly in dengue burden countries. Methods: Children aged less than 15 years who sought medical care in the pediatric department of Saveetha medical college, diagnosed as Probable Dengue/Dengue fever/ dengue with warning sign/severe dengue according to standard guidelines during the study period (July 2017 – December 2017) comprised the study sample. Results: A total of 61 cases were enrolled, of these 36 were boys. The mean age was 6.49 years. Only five patients had severe dengue. Fever(96.7%), loss of appetite (59%), cough and running nose (33%) were common symptoms noted and itching (37.7%) was common during recovery. Only 11.4% of children had bleeding manifestation. Hepatomegaly was noticed in 35 children. Five children went into shock, 2 of whom had hypotension. NS1 was positive in 49%, IgM in 36%, and IgG in 13%. NS1 positivity rate on day 4, day 5 and day 6 of illness were 62.5%, 38.4% and 18.1% respectively. Conclusion: Dengue fever is common during monsoon season, and the course and severity are highly variable. Though the manifestations of dengue are similar to other viral infections, morbidity and mortality are more, thus requiring early diagnosis. As observed in our study the presence of prodromal respiratory symptoms does not preclude the diagnosis of dengue. There should be a high index of suspicion of co-infection, notablymalaria and scrub typhus, if there is an unusual persistence of fever.

NS 1 lasts longer than the dengue virus nucleic acid in the clinically suspected patients with dengue fever and dengue haemorrhagic fever.

The objectives of the study were to compare the DENV NS1 and nucleic acid positivity in dengue fever (DF) and dengue haemorrhagic fever (DHF) patients and to evaluate the usefulness of these parameters in severe dengue. Blood samples were collected from 91 patients with DF or DHF (fever days 3-9) from Gampaha and Negombo General Hospitals, Sri Lanka and tested for DENV NS1 antigen and nucleic acid. On fever day 3, 67% of the DF and 33% of the DHF patients had DENV nucleic acid whereas 50% of the DF and 67% of the DHF patients had NS1. On fever day 4, 67% of the DF and 100% of the DHF patients had DENV nucleic acid whereas 83% of the DF and DHF patients had NS1. From fever day 5 in the DHF group, DENV nucleic acid declined but NS1 remained detectable even on day 9 (p<0.0001). NS1 positivity did not correlate with the decrease in the WBC count in DF and DHF patients (p>0.05) whereas NS1 positivity significantly correlated with the decrease in the platelet count in DF and DHF patients (p<0.0001). NS1 is a useful marker to detect DENV infection even in the latter stages of DHF.

Serum Ferritin: A Backstage Weapon in Diagnosis of Dengue Fever.

Aims This retrospective study evaluates ferritin as a surrogate marker for dengue infection (NS1 and IgM negative stage) as opposed to other febrile illnesses of infective or inflammatory etiology (OFI). Methodology Data of all patients admitted to medical ward and medical ITU during the dengue outbreak were collected. Patients admitted between 5 and 10 days of febrile illness without a diagnosis were included. Patients with NS1 positivity (Days 2–8) and/or positive IgM for dengue (Days 6–10) were considered to be dengue cases and those with other confirmed diagnoses were considered in the OFI group. Ferritin, CRP, TC of WBC, platelet count, SGOT, SGPT, and albumin levels were analysed for both groups. Results We examined 30 cases of clinically and serologically confirmed dengue fever and 22 cases of OFI. Ferritin level in dengue cohort was significantly higher than the OFI group (p < 0.0001). The best cut-off for ferritin level to differentiate dengue from OFI was found to be 1291. The sensitivity at this cut-off is 82.6% and the specificity at this cut-off is 100%. Conclusion Ferritin may serve as a significant marker for differentiating between dengue fever and OFI, in absence of a positive NS1 antigen or a positive IgM antibody for dengue.

NS1: An early Diagnostic Tool for Dengue Virus Fever

Dengue virus is a highly prevailing unremitting pathological menace in the developing countries like Pakistan. The variation in the type and frequency of dengue infection demands a continuous surveillance on its spread and diagnosis, in order to develop appropriate management and therapeutic strategies. Dengue Virus is highly complex disease with various manifestations. It is hard to characterize the dengue viral infection with ordinary laboratory tests. However, NS1 could serve a good diagnostic tool in the first few days of fever. In this research, 88 patients from Lahore regions of Punjab were analysed for the presence of dengue specific NS1 antigen from 1 to 30 days of dengue fever. ELISA based kit was employed. The obtained data was analysed expressed percentage frequency of NS1 positive and negative along with IgM positive and negative in all dengue fever patients. Importantly it was observed that 36.3 % were infected by dengue. NS1 antigen was efficiently quantified at earlier days of infection. IgM was negative in all the subjects who were positive for NS1 on the second day of fever. However, this association weakened with the progression of fever. It was analysed that thrombocytopenia and leuckocytopenia are not linked with the NS1 positivity and these states were random. It can be inferred that dengue diagnosis is very complicated and the antigenic profile dramatically changes with the progression of fever in terms of days. Clinicians should employ a diagnostic method based on a comprehensive analysis of subjects in order to minimize

Changing trends in clinicopathological parameters in dengue with evaluation of predictors of poor outcome in children

Background: A study was planned to evaluate the changing trends in dengue according to the revised WHO guidelines in children and at identifying and evaluating the association between clinical features the child and the outcome. Methods: This was a retrospective observational study conducted in Safdarjung Hospital. Children with signs and symptoms of dengue fever along with serological or antigen NS1 positivity were included. Continuous variables were analysed using percentage, mean, standard deviation. Categorical variables were analysed using chi-square test. P value 5 days) (p < 0.000) and progression to shock. Conclusions: Lethargy, presence of more than 3 warning signs at the time of presentation can be used as predictors of severe dengue.

Assessing positivity and circulating levels of NS1 in samples from a 2012 dengue outbreak in Rio de Janeiro, Brazil.

Dengue virus (DENV) represents a major threat to public health worldwide. Early DENV diagnosis should not only detect the infection but also identify patients with a higher likelihood to develop severe cases. Previous studies have suggested the potential for NS1 to serve as a viral marker for dengue severity. However, further studies using different sera panels are required to confirm this hypothesis. In this context, we developed a lab-based ELISA to detect and quantitate NS1 protein from the four DENV serotypes and from primary and secondary cases. This approach was used to calculate the circulating NS1 concentration in positive samples. We also tested the NS1 positivity of DENV-positive samples according to the Platelia Dengue NS1 Ag assay. A total of 128 samples were positive for DENV infection and were classified according to the WHO guidelines. The overall NS1 positivity was 68% according to the Platelia assay, whereas all samples were NS1-positive when analyzed with our lab-based ELISA. Fifty-four samples were positive by PCR, revealing a co-circulation of DENV1 and DENV4, and the NS1 positivity for DENV4 samples was lower than that for DENV1. The circulating NS1 concentration ranged from 7 to 284 ng/mL. Our results support previous data indicating the low efficiency of the Platelia assay to detect DENV4 infection. Moreover, this work is the first to analyze NS1 antigenemia using retrospective samples from a Brazilian outbreak.

Pancreatitis and MODS Due to Scrub Typhus and Dengue Co-Infection

We report a 40 year old woman admitted with an acute abdomen. Investigations revealed pancreatitis, bilateral pleural effusion, renal failure, disseminated intravascular coagulation, and scrub IgM ELISA and dengue NS1 positivity. She improved with azithromycin and appropriate pain and fluid management. She also developed central venous catheter-related MRSA sepsis that was managed in the hospital.

Comparison of two dengue NS1 rapid tests for sensitivity, specificity and relationship to viraemia and antibody responses

BackgroundDengue is a major public health problem in tropical and subtropical countries. Rapid and easy diagnosis of dengue can assist patient triage and care-management. The detection of DENV NS1 on rapid lateral flow tests offers a fast route to a presumptive dengue diagnosis but careful evaluations are urgently needed as more and more people use them.MethodsThe sensitivity and specificity of the Bio-Rad NS1 Ag Strip and SD Dengue Duo (NS1/IgM/IgG) lateral flow rapid tests were evaluated in a panel of plasma samples from 245 Vietnamese patients with RT-PCR confirmed dengue and 47 with other febrile illnesses.ResultsThe NS1 rapid tests had similar diagnostic sensitivities (respectively 61.6% and 62.4%) in confirmed dengue cases but were 100% specific. When IgM/IgG results from the SD Dengue Duo were included in the test interpretation, the sensitivity improved significantly from 62.4% with NS1 alone to 75.5% when NS1 and/or IgM was positive and 83.7% when NS1 and/or IgM and/or IgG was positive. Both NS1 assays were significantly more sensitive for primary than secondary dengue. NS1 positivity was associated with the underlying viraemia as NS1-positive samples had a significantly higher viraemia than NS1-negative samples.ConclusionsThese data suggest that the NS1 test component of these assays are highly specific and have similar levels of sensitivity. The IgM parameter in the SD Duo test improved overall test sensitivity without compromising specificity. The SD Dengue Duo lateral flow rapid test deserves further prospective evaluation in dengue endemic settings.

Diagnostic Accuracy of NS1 ELISA and Lateral Flow Rapid Tests for Dengue Sensitivity, Specificity and Relationship to Viraemia and Antibody Responses

BackgroundDengue is a public health problem in many countries. Rapid diagnosis of dengue can assist patient triage and management. Detection of the dengue viral protein, NS1, represents a new approach to dengue diagnosis.Methodology/Principal FindingsThe sensitivity and specificity of the Platelia NS1 ELISA assay and an NS1 lateral flow rapid test (LFRT) were compared against a gold standard reference diagnostic algorithm in 138 Vietnamese children and adults. Overall, the Platelia NS1 ELISA was modestly more sensitive (82%) than the NS1 LFRT (72%) in confirmed dengue cases. Both ELISA and LFRT assays were more sensitive for primary than secondary dengue, and for specimens collected within 3 days of illness onset relative to later time points. The presence of measurable DENV-reactive IgG and to a lesser extent IgM in the test sample was associated with a significantly lower rate of NS1 detection in both assays. NS1 positivity was associated with the underlying viraemia, as NS1-positive samples had a significantly higher viraemia than NS1-negative samples matched for duration of illness. The Platelia and NS1 LFRT were 100% specific, being negative in all febrile patients without evidence of recent dengue, as well as in patients with enteric fever, malaria, Japanese encephalitis and leptospirosis.Conclusions/SignificanceCollectively, these data suggest NS1 assays deserve inclusion in the diagnostic evaluation of dengue patients, but with due consideration for the limitations in patients who present late in their illness or have a concomitant humoral immune response.