Early Diagnosis Of Dengue Research Articles

Utility of Fluorescence Immunoassay in Early Diagnosis of Dengue

Utility of Fluorescence Immunoassay in Early Diagnosis of Dengue

Comparison of NS1 Antigen Detection by RDT and ELISA and its Concordance with RT-PCR for the Early Diagnosis of Dengue in Ananthapuramu District, Andhra Pradesh, India

Introduction: Early detection of dengue fever is important for effective clinical care and vector control. For the detection of dengue viral antigen and antibodies, several serological techniques based on the concept of immunochromatography and Enzyme-Linked Immunosorbent Assays (ELISA) are routinely utilised. The performance of these tests depends on the sensitivity and specificity. Aim: To compare Non Structural protein-1 (NS1) antigen detection by Rapid Diagnostic Tests (RDTs) and ELISA and its association with Real-Time Polymerase Chain Reaction (RT-PCR). Materials and Methods: This diagnostic cross-sectional study was done on 100 clinically suspected cases of Dengue between July-November 2021 at a tertiary care hospital in Ananthapuramu, Andhra Pradesh, India. All the sera samples were collected and subjected to NS1 antigen detection test by rapid test, NS1 ELISA, and RT-PCR, and also serotypes DENV-1, 2, 3, 4 were detected from serum sample by RT-PCR test. The results of rapid and ELISA tests were compared with RT-PCR. Data was analysed by Statistical Package for the Social Sciences (SPSS) version 16.0. Results: Out of total 100 samples, 29 samples were tested positive by NS1 rapid test, 30 samples were tested positive by NS1 ELISA, and 32 samples were tested positive by RT-PCR. The sensitivity, specificity of dengue NS1 antigen rapid test were 87.50% and 98.52%, respectively when compared to RT-PCR whereas that of NS1 ELISA were 93.75% and 100% when compared to RT-PCR. Out of 32 samples tested positive by RT-PCR, two samples were positive for DENV-1, 26 samples were positive for DENV-2, and four samples were positive were DENV-3. Conclusion: The NS1 ELISA test requires extra procedures and time. RDTs need a one-step operation that takes roughly 15-30 minutes. Despite the fact that RT-PCR and ELISA have better performance than RDTs, RDTs are more effective for early diagnosis and therapy of dengue fever in countries with limited infrastructure and in remote places.

Comparison of NS1 Antigen Detection by Rapid Immunochromatography Test and ELISA for Early Diagnosis of Dengue at a Government General Hospital, Ananthapuramu

Background: The incidence of Dengue hemorrhagic fever, Dengue shock syndrome associated with Dengue can be reduced by diagnosing Dengue early and by initiating early treatment to Dengue patients. This study was conducted to compare results of NS1 antigen rapid test and ELISA in clinically suspected dengue patients.
 Materials and Methods: Present study was a comparative study conducted on 100 Patients presented with clinical history of Dengue. At Microbiology Laboratory, serum of all samples was assessed for NS1 detection using antigen Rapid test and ELISA. Sensitivity & specificity values were calculated for NS1 antigen rapid test, compared with ELISA.
 Results: Out of 100 serum samples collected from suspected cases of Dengue in and around Anantapuramu, 30 (30%) were positive for ELISA and 28 (28%) were positive for Rapid diagnostic test. Sensitivity & specificity when only NS1 was considered on rapid test kits when compared with ELISA were 93.33%, 98.57%,
 Conclusion: It is concluded that ELISA test was superior in the diagnosis of Dengue and recommended on improvement in sensitivity of RDTs.

Dengue Virus Non-structural (NS) 1 Gene as A Molecular Marker for Early Detection of in vitro Dengue Virus Infection

Serology-based dengue assays at times produce inaccurate results especially in the early phase of disease onset. A more precise diagnostic approach detecting dengue infections in the early phase enables better management of the disease. This helps reduce dengue-associated morbidity and mortality. Besides, an early diagnosis of dengue is also very beneficial in a dengue outbreak and in endemic regions. In this light, this study aimed to determine the potential of the dengue virus (DENV) non-structural 1 (NS1) gene as an early detection biomarker. The cytopathic effects (CPE) were monitored and the cell death of DENV serotype-2 (DENV2)-infected Vero cells was evaluated for fourteen consecutive days. Only Lemos and in-house NS1-specific primer pairs showed positive amplifications in the preliminary primer validation. Thus, both of the primer pairs were then used to amplify the NS1 gene from the infected cells. The NS1 gene was detected as early as day-2 post-infection using the in-house primers. There was no amplicon produced using the Lemos primers. This is speculated to be attributable to the relatively lower complementarity of the primer sequences with that of the template and low amount of viral mRNA in the DENV2-infected cells. Conclusively, the DENV NS1 gene is a potential early detection marker, however, the NS1-specific primers should be pre-validated to ensure a reliable dengue diagnosis.

Comparison of two rapid test kits with real time polymerase chain reaction for early diagnosis of dengue in Sri Lanka

ABSTRACT Dengue is among the deadliest insect-borne diseases circulating in Sri Lanka. Most of the infections that are diagnosed early are manageable. However, delays in diagnosis may cause fatalities. We evaluated the dengue NS1 antigen card and NS1 SD kit for early diagnosis of dengue using samples from 116 RT-PCR-positive patients admitted within 5 days of the fever onset. RT-PCR tests were performed as standard tests. IgM and IgG ELISA tests were carried out to identify primary and secondary infections. Of the 116 patients who tested positive for dengue using PCR, 48 were positive using NS1 antigen card and 45 were positive using NS1 SD. Patients with 100 copies or higher viral load showed a higher sensitivity in both antigen card and NS1 SD. Of 34 primary infections evaluated, 23 were positive by NS1 antigen card, while the positivity was 21 by NS1 SD. Of the 30 secondary infections evaluated, 15 were positive by NS1 antigen card while 14 by NS1 SD. Our findings showed that while the rapid tests are convenient and much easier to use than PCR, they are less sensitive and need improvement. Until then, clinical diagnosis should have more emphasis on the early diagnosis of dengue.

Production of Properly Folded NS1 Protein in Bacterial Cells.

Dengue virus (DENV) NS1 protein is a multifunctional protein involved in several pathogenic processes but also has been described as a protective antigen suitable for eliciting humoral response against DENV. NS1 is essential for virus replication and can be found in different cell compartments and at different oligomeric states. It is secreted to the extracellular medium and can also be found circulating in the blood of infected patients, being routinely used as the serum biomarker for early dengue diagnosis. High-yield production of the recombinant NS1 protein in a native-like conformation is essential for studies regarding its function during DENV infection as well as to those interested in the development of new diagnostic approaches based on this protein. In this chapter, we describe an optimized protocol for high-yield expression of native-like NS1 in Escherichia coli bacterial cells.

The Prognostic Significance of Established Hematological Parameters and Inflammatory Biomarkers in Assessing Dengue Infection Severity and Progression among Patients Ages 5 to 14 in a Tertiary Government Hospital in Pampanga, Philippines

Abstract Introduction/Objective Dengue virus (DENV) is an arthropod-borne virus which imposes a significant burden on the health system in most tropical and subtropical countries. In 2009, WHO classified Dengue into Dengue Without Warning Signs (DNWS), Dengue With Warning Signs (DWWS), and Severe Dengue (SD). This study aims to establish the prognostic value of predetermined hematological parameters and inflammatory biomarkers in assessing severity and progression of dengue infection among ages 5-14. Methods/Case Report A retrospective study was conducted to evaluate the Complete Blood Count, Inflammation biomarkers, and severity of dengue patients (5-14 of age). The diagnosis must be serologically confirmed by a positive NS1/IgM. Results (if a Case Study enter NA) A total of 36 patients participated in the study, having 18 from each groups of DWWS and SD. The mean age of Dengue cohort was 13.9 years with 59% (19/36) being male. Laboratory findings reveal SD to have lower platelet count (<100.00x109/L) during day 1-3 (p<0.001). Low WBC count (<4.00x109/L), Relative Eosinophil (<2.00%), and Absolute Lymphocyte count (<1.52x109/L) were evident on days 1-3 among DWWS and SD cases (p=0.023; p=0.045; p=0.033). Low relative neutrophil (<0.45%) was a constant finding in both clinical types throughout disease progression. SD group had significantly higher Neutrophil to Lymphocyte ratio (NLR) values among SD cases on days 4-6 (p<0.001). In contrast, Platelet to Lymphocyte ratio (PLR) was significantly lower among DWWS cases on days 4-6 (p=0.020). Monocyte to Lymphocyte (MLR) ratio had poor discriminative power (p=0.560). Conclusion The findings highlight decreased platelet, WBC, relative eosinophil, and absolute lymphocyte count to be common among Dengue patients. NLR and PLR were found to be good predictors of dengue severity during the initial phase of infection. Evaluating these values may aid clinicians in early diagnosis of severe dengue. However, larger samples are needed to further validate the predictive values of these parameters.

Comparative evaluation of dengue NS1 antigen rapid test and IgM ELISA in a tertiary care hospital in VIMS, Ballari

Dengue virus infection is becoming a major public health problem in recent decades because of the mortality and morbidity associated with it. Dengue is endemic in many parts of India and epidemics are frequently reported from various parts of India and abroad. The mortality rate in patients with dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) is as high as 44%. Hence early and rapid laboratory diagnosis of dengue is crucial. Appropriate clinical management can save the lives of DHF and DSS patients and mortality can be reduced to less than 1%. It is also worthwhile for planning appropriate control strategies. The present communication reports the seroprevalence of dengue infections occurred in Central India.To detect Dengue infection by NS1 Antigen Rapid detection and by IgM ELISA and compare Rapid NS1 Antigen detection test and IgM ELISA test.Blood samples from 5273 suspected cases were collected from January 2016 to December 2016. Sera were separated and subjected for NS1 antigen detection testing by the solid phase immunochromatographic assay, a commercial dengue virus rapid test kit. and antidengue IgM antibody ELISA in the Department of Microbiology, VIMS, Ballari. All samples were put for ELISA.3036 samples were tested for NS1 Antigen detection rapid method.2272 samples were tested for both rapid test and ELISA. Out of 5273 cases, 446 (8.46%) were found to be positive by IgM ELISA. 3036 samples WHICH were tested for NS1 Antigen detection by rapid method 208 (6.85%)samples were positive. The most affected age group was 5-10yrs with 284 cases, out of which 29 were positive, followed by the age group 0f 15yrs and above with 8.74%. Males were affected more than females with a percentage of 9.2 and 7.4 respectively. The highest number of suspected dengue patients admitted was in the month of November, i.e., 459 with 68 positive (14.81%) followed by August (12.16%) and September (11.03%), i.e., 28 with 7 (25%) positive. For the 2272 samples for which both tests were done, 153 cases were positive for rapid test and 137 cases were positive by ELISA. Dengue cases were more during September to November in the post monsoon season which is useful to plan special preventive strategies. The study draws attention toward the male, young and adult age group. To conclude, in countries lacking infrastructure for the diagnostic labs especially in the rural and remote areas, the rapid dengue ICT tests can play a major role in diagnosis and in patient management of acute dengue infection. The rapid ICTs are very simple, easy to perform, and can be used as point of care tests. We suggest that the rapid ICT for NS1 Ag detection may be used in patients presenting with fever less than 5 days

Clinical features & outcome of dengue cases at a tertiary care centre

Background: Dengue is a very common seasonal public health problem causing significant mortality every year. In 2019 an outbreak occurred in Bangladesh. Few new manifestations and multi organ involvement were found.
 Objective: The objective of the study was to see the clinical and laboratory manifestations and outcome of dengue fever in a medical college hospital.
 Methods: It was an observational study in a medical college hospital in Bangladesh. Study period was one year. The patients were confirmed cases of dengue. Apart from detailed clinical history, examination of patient, relevant investigations and follow up was done until discharge.
 Result: Total number of cases was 98. Out of them 62 (63.2%) were male and 36 (36.73%) were female. Fever was most common (100%) manifestation and duration of fever ranged from 5 to 8 days with a mean duration of 6.3 (± 1.0) days. Among other symptoms generalized body ache was most common (63, 64.3%). Generalized weakness was present in 60 cases (61.2% cases) Bleeding manifestations was present in 41 cases; abdominal manifestations were found in 11 cases. Blood for NSI was positive in 94 (95.9%) cases; most cases (71, 72.4%) became positive between 2nd to 4th day. Ninety (91.9%) cases developed thrombocylopcnia and it started at 5th day in 45 (45.9%) cases. Blood transfusion was given in 12 (12.2%) cases & Platelet transfusion was given in 3 (3.1%) cases. Complete recovery was in 96 (98%) cases and Death occurred in 2 (2.0%) cases.
 Conclusion: Bleeding was a dominant presentation. Some atypical manifestations like gastro intestinal features were also observed. These findings will help physicians in early diagnosis of dengue.
 Bang Med J Khulna 2020: 53 : 3-7

High performance dengue virus antigen-based serotyping-NS1-ELISA (plus): A simple alternative approach to identify dengue virus serotypes in acute dengue specimens.

Dengue hemorrhagic fever (DHF) is caused by infection with dengue virus (DENV). Four different serotypes (DENV1-4) co-circulate in dengue endemic areas. The viral RNA genome-based reverse-transcription PCR (RT-PCR) is the most widely used method to identify DENV serotypes in patient specimens. However, the non-structural protein 1 (NS1) antigen as a biomarker for DENV serotyping is an emerging alternative method. We modified the serotyping-NS1-enzyme linked immunosorbent assay (stNS1-ELISA) from the originally established assay which had limited sensitivity overall and poor specificity for the DENV2 serotype. Here, four biotinylated serotype-specific antibodies were applied, including an entirely new design for detection of DENV2. Prediction of the infecting serotype of retrospective acute-phase plasma from dengue patients revealed 100% concordance with the standard RT-PCR method for all four serotypes and 78% overall sensitivity (156/200). The sensitivity of DENV1 NS1 detection was greatly improved (from 62% to 90%) by the addition of a DENV1/DENV3 sub-complex antibody pair. Inclusive of five antibody pairs, the stNS1-ELISA (plus) method showed an overall increased sensitivity to 85.5% (171/200). With the same clinical specimens, a commercial NS1 rapid diagnostic test (NS1-RDT) showed 72% sensitivity (147/200), significantly lower than the stNS1-ELISA (plus) performance. In conclusion, the stNS1-ELISA (plus) is an improved method for prediction of DENV serotype and for overall sensitivity. It could be an alternative assay not only for early dengue diagnosis, but also for serotype identification especially in remote resource-limited dengue endemic areas.

Detection and confirmation of dengue pre- and postintroduction of dengue NS1-antigen test at the University Malaya Medical Centre: An observational study.

Early diagnosis of dengue is important to ensure proper management of patients and effective implementation of control measures. The present study was undertaken to determine the outcome of the implementation of dengue NS1-antigen (Ag) rapid diagnostic test (RDT) in the confirmation of dengue at the first patient hospital visit at the University Malaya Medical Centre. A total of 1036 and 1097 sera from the year 2008 and 2015 were used, representing samples from before and after dengue NS1-Ag RDT was implemented as routine diagnostic at the hospital. Results showed that similar dengue confirmation percentage (56%) was made in 2008 and 2015, regardless of the main laboratory diagnostic method used. Confirmation of dengue, however, increased to 68% and 73% when dengue NS1-Ag test or dengue immunoglobulin M-capture enzyme-linked immunosorbent assay was used as the second test for the 2008 and 2015 samples, respectively. Detection of dengue virus (DENV) using multiplex reverse transcription-polymerase chain reaction (RT-PCR) showed that DENV-1 was the highest in circulation in 2008 and that both DENV-1 and DENV-2 were dominant in 2015. In summary, the present study demonstrated that the introduction and use of the dengue NS1-Ag RDT did not change or compromise confirmation of dengue, highlighting the advantage of using the method. With the reducing cost of molecular detection tools, DENV detection using RT-PCR remains a viable option for further confirmation of dengue in hospital settings.

Clinical features and outcomes of neonatal dengue at the Children's Hospital 1, Ho Chi Minh, Vietnam.

Objectives Neonatal dengue has been reported in the literature with contradictory findings of clinical characteristics and diagnosis; thereby, misdiagnosis of neonatal dengue has been frequently reported. We aim to delve into the epidemiology, clinical features, and outcomes of neonatal dengue, thus avoid misdiagnosis and obtain early intervention. Study design A retrospective study was conducted at Children's Hospital 1, Ho Chi Minh, Vietnam with laboratory-confirmed dengue in neonates by positive viral antigen nonstructural protein one rapid test (NS1) and positive IgM antibody for dengue by MAC-ELISA. Results We have included 32 neonates in this study with 25% cases were misdiagnosed with neonatal sepsis, and 12.5% cases were misdiagnosed with neonatal immune thrombocytopenia at the beginning. The median time between the first day of the mother's onset of fever and childbirth was -1 days (IQR: -2, 2). The patient's clinical manifestation included: petechiae 87.5% (28/32), pharyngeal mucosal hemorrhage 6.3% (2/32), and hepatomegaly occurred 75% (24/32). In the febrile phase (day of illness 1-3), the mean white blood cell (WBC) counts were 7800 ± 800/mm3 and platelets were 97,111 ± 37,826/mm3. In the critical phase (day of illness 4-6), the mean WBC counts were 13,400 ± 2800/mm3, and platelets were 30,100 ± 5749/mm3. All mothers (100%) had laboratory-confirmed dengue by NS1 positive in the perinatal period. Conclusions The findings emphasize that early diagnosis of neonatal dengue should be based on a history of maternal illness, NS1 rapid test, and clinical presentation such as petechiae, hepatomegaly, and low platelet counts in the febrile phase.

Use of Cerebrospinal Fluid for the Diagnosis of Neuroinvasive Dengue, Zika, and Chikungunya: A 19-year systematic review.

INTRODUCTION: Cerebrospinal fluid analysis contributes to the diagnosis and neuropathogenesis of neuroinvasive arboviruses. Neurological complications caused by dengue, Zika, and chikungunya infections have high clinical relevance because of their high potential to cause death or neurological deficits. We aimed to evaluate the use of cerebrospinal fluid assays for diagnostic support in neurological disorders associated with dengue, chikungunya, and Zika infections. METHODS: A systematic review was carried out by searching the electronic databases LILACS, PubMed, Scopus, and Embase for articles written in English, Portuguese, or Spanish in the last 19 years. Published studies were reviewed using the terms “dengue,” “Zika”, “chikungunya”, alone or in combination with “cerebrospinal fluid” in the period from 2000 to 2019. RESULTS: A total of 98,060 studies were identified; of these, 1.1% (1,041 studies, 58,478 cases) used cerebrospinal fluid assays for neurological investigations. The most frequent neurological disorders included encephalitis (41.4%), congenital syndromes (17%), and microcephaly associated with Zika virus infections (8.9%). Neuroinvasive disorders were confirmed in 8.03% of 58,478 cases by specific cerebrospinal fluid analyses. The main methods used were IgM-specific antibodies (66%) and reverse transcription-polymerase chain reaction (10%). The largest number of scientific papers (29%) originated from Brazil, followed by India (18.4%) and the United States (14.4%). CONCLUSIONS: Although cerebrospinal fluid analysis is of great importance for increasing neurological diagnostic accuracy and contributes to the early diagnosis of neuroinvasive dengue, chikungunya, and Zika infections, it is underused in routine laboratory investigations worldwide.

Mucocutaneous manifestations in dengue: A study among children at a tertiary care center in South India

Introduction: Dengue, a viral illness, is a major public health problem. Mucocutaneous manifestations are known to occur in this illness. Over the past three decades, there has been a dramatic global increase in the incidence of dengue fever (DF). Our objective was to study the frequency and pattern of mucocutaneous manifestations of DF in children. Methodology: A total of 210 consecutive cases, which were serologically confirmed and admitted to pediatric ward over a period of 12 months (January to December 2018), were included. A detailed clinical history, examination and relevant investigations were carried out. Data were entered into a pro forma and analyzed using simple statistical methods and Chi-square test (wherever applicable). Results: The most common age group affected was 4.1–8 years with a mean age of 6.3 ± 3.9 years. Male children were more commonly affected, with majority from urban areas. Maximum cases were noted during the months from October to December, i.e., winter season. Mucocutaneous findings were noted in 112 (53.3%) cases. Cutaneous rash was present in 43 (20.1%) cases. The most common site involved was trunk, followed by face and others. Macular erythema was the most common type of rash. Onset of rash was more commonly seen in children with depleted platelet count. Ocular and oral mucosae were involved in 56 (26.7%) and 42 (20.1%) cases, respectively. Conclusion: Mucocutaneous manifestations are relatively common in children with dengue. Cutaneous rash may be a useful clinical clue for early diagnosis of dengue. Awareness of mucocutaneous manifestations helps in early recognition and proper management of dengue.

Serological and haematological profile for early diagnosis of dengue infection in tertiary care hospital

Context: Dengue is a major public-health concern throughout tropical and subtropical regions of the world including India. All four serotypes of the dengue can produce wide range of the symptoms from mild clinical diseases to sever diseases. Dengue haemorrhagic fever and dengue shock syndrome may occur in secondary dengue infection with serotype other than primary infection. Early diagnosis is required for proper management of this disease and to reduce mortality. Aim and Objectives: Present study was carried out to know prevalence of dengue in Gujarat, its epidemiological status and to co-relate the serological and haematological data for early diagnosis of dengue infection. Materials and Methods: A retrospective study was carried out over a period of one year from January 2016 to December 2016. A total of 12,413 samples having signs and symptoms of dengue fever were processed for NS 1 Ag detection and IgM Ab detection test by ELISA according to their duration of illness. Laboratory tests of dengue positive parameters and its haematological profile were co-related. Results: A total of 1430 samples (11.52%) were positive for dengue. Males in the age group of 16yrs to 30 yrs were predominantly affected. Monsoon and post-monsoon is a most favourable season for dengue transmission. Thrombocytopenia was more consistently associated whenever IgM was detected compared to NS1 detection. Conclusions: Early recognition and diagnosis are important for favourable outcome. NS 1 Ag detection test by ELISA can give positive results from the 1st day of illness. Haematological profile acts as indicators for provisional and early diagnosis of dengue. Keywords: IgM antibody, NS1 antigen, Thrombocytopenia.

Clinico-Laboratory Profile of Dengue Patients at Sir T. Hospital, Bhavnagar, India

Dengue fever is caused by any one of four types of dengue viruses (DEN1-DEN4), spread mainly by Aedes aegypti. India had the largest number of dengue cases, with about 33 million apparent and another 100 million asymptomatic infections occurring annually. The patients typically present with the sudden onset of fever, frontal headache, retroorbital pain. The laboratory diagnosis can be made by IgM ELISA or by NS1 antigen-detection ELISA during the acute phase. This research was conducted from January 2018 to December 2018 at Sir T. hospital and Government Medical College in Bhavnagar, Gujarat. The patients having complaints of fever, headache, myalgia, arthralgia or rash, were clinically examined, and laboratory investigated for dengue with NS1 and/or IgM dengue antibody. A total of 536 patients was screened, of which 112 patients were diagnosed as dengue fever at 21% dengue positivity rate, based on detection of NS1 (46/304, 15%), and antidengue IgM (66/232, 28%) in their sera. The majority of the patients were males (77/112, 69%). The majority of patients were in 11–30 years’ age group (66/316, 21%). Fever (100%) was the chief presenting complaint, followed by headache (83, 93%), and myalgia (79, 89%). The highest number (28) of dengue patients was observed in the month of October 2018. According to this study results, the physicians in the dengue-endemic area should be aware of dengue in acute febrile illnesses and use the appropriate laboratory tests such as NS1 antigen and IgM antibodies for early dengue diagnosis. This can help clinicians to prevent morbidity and mortality associated with dengue.

Utility of a Multiplex Real-Time Polymerase Chain Reaction for Combined Detection and Serotyping of Dengue Virus in Paediatric Patients Hospitalised with Severe Dengue: A Report from Chennai

AbstractObjective: Molecular detection and serotyping are rapid, sensitive and accurate techniques for early diagnosis of paediatric dengue. The present study evaluates multiplex real-time polymerase chain reaction (PCR) for diagnosis of dengue virus in children hospitalised with severe dengue (SD) and attempts to establish an association of clinical severity with specific serotypes. Methods: Four hundred and eighty-five samples were received from hospitalised paediatric patients with suspected dengue from March 2019 to February 2020. Multiplex real time PCR was employed for diagnosis. An in-house real-time PCR that combined diagnosis and serotyping was established. Non-structural protein 1 (NS1) assay and real-time PCR were assessed for their accuracy in diagnosing severe paediatric dengue. Results: Three hundred and twenty-five (67%) patients were positive for dengue RNA by real-time PCR. All four serotypes were identified throughout the year; dengue serotype 2 (DEN-2) was predominant (61%) followed by DEN-3, 20%. Compared to the commonly used NS1 testing, multiplex real-time PCR showed greater sensitivity in diagnosing SD. Conclusions: Compared to NS1, multiplex real-time PCR is a rapid and accurate diagnostic test for children hospitalised with SD. DEN-2 was the predominant serotype in severe cases. Continued surveillance of serotypes should be carried out year-round in endemic areas.

Quartz Crystal Microbalance Aptasensor for the Molecular Detection of Dengue Virus

Introduction Dengue fever is the major public health concern in the Philippines and is endemic in all regions of the country in which all serotypes are present[1]. Despite the widespread nature of the virus transmitted by mosquitos, molecular diagnostics have significant limitations. An early diagnosis of dengue may prevent severe clinical complications associated with the infection. A novel genosensor using an aptamer for the detection of dengue virus serotypes 1-4 was demonstrated in this study. Method This genosensor composed of a thiolated aptamer immobilized on a 10MHz gold electrode QCM targeting the 3’ untranslated region of all complete genome sequences of dengue virus available in GenBank[2]. Aptamer concentration, buffer pH and ionic strength of buffer solutions were optimized to achieve the highest sensitivity of the QCM genosensor. Atomic force microscopy [3], electrochemical impedance spectrum (EIS) measurements and cyclic voltammetry (CV) were used to characterize the surface of the QCM electrode prepared[4]. Evaluation of binding kinetics and affinity study of the Aptamer-dengue genome was determined by surface plasmon resonance (SPR)[5]. Results and Conclusions Atomic Force Microscopy (AFM), Electrochemical Impedance (EIS) and Cyclic Voltammetry (CV) have been used to characterize the surface of the PQC electrode. The AFM results indicate that the thiolated aptamer onto the electrode has decreased the roughness of gold surface by forming a uniform layer on the electrode surface. The EIS and CV results indicate that the charge transfer resistance is increased after immobilization of the aptamer onto the bare gold electrodes, indicating that direct S-Au bonding via disulfide moieties and the negative charge of protein have blocked the electrode reaction between Fe (II) and Fe (III). The results showed that the developed aptamer QCM sensor has an optimum concentration range of the target dengue genome is 20–100 mg/ml for hybridization. This work demonstrated the possibility of using an immobilized aptamer on a QCM and other sensor platforms for the direct detection of the RT-PCR products of dengue virus serotypes 1-4.

Hybrid Convolutional Neural Network with PSO Based Severe Dengue Prognosis Method in Human Genome Data

Dengue is one of the most significant diseases transmitted by arthropods in the world. Dengue phenotypes are focused on documented inaccuracies in the laboratory and clinical studies. In countries with a high incidence of this disease, early diagnosis of dengue is still a concern for public health. Deep learning has been developed as a highly versatile and accurate methodology for classification and regression, which requires small adjustment, interpretable results, and the prediction of risk for complex diseases. This work is motivated by the inclusion of the Particle Swarm Optimization (PSO) algorithm for the fine-tuning of the model's parameters in the convolutional neural network (CNN). The use of this PSO was used to forecast patients with extreme dengue, and to refine the input weight vector and CNN parameters to achieve anticipated precision, and to prevent premature convergence towards local optimum conditions.

The inability of a dengue NS1 ELISA to detect Zika infections

The presence of dengue virus (DENV), Zika virus (ZIKV) and Chikungunya virus (CHIKV) in Brazil, may result in a difficult diagnosis due to the signs and symptoms shared by those. Moreover, as DENV and ZIKV belong to the same family, serological assays may show a high rate of cross-reactivity. Here, we evaluated a Dengue NS1 capture assay for early and differential diagnosis of dengue during the Zika epidemic occurred in Brazil in 2016. Samples (n = 227) from 218 patients included sera, plasma and urine from previously confirmed acute cases of Zika, dengue and Zika/dengue co-infections. Nine of those patients presented two specimens. The Dengue NS1 test was very specific for dengue diagnosis (99.32%), even in the co-circulation with ZIKV, and exhibited a high accuracy in not detecting acute Zika infections (92.43%). Our findings showed that the dengue NS1 capture test analyzed here was not able to recognize the ZIKV NS1 and its potential for cross-reaction.