Case Management of Dengue: Lessons Learned

An Intriguing Case of Expanded Dengue Syndrome With Co-existing Encephalitis, Pancreatitis, and Hepatitis: The Classic Thalamic "Double-Doughnut" Sign Revisited

Background

Dengue neuro-infection can present with symptoms ranging from mild to severe. Atypical presentations, such as expanded dengue syndrome, pose diagnostic and therapeutic challenges. Neuroimaging findings, particularly the "double-doughnut" sign on brain magnetic resonance imaging (MRI), have emerged as one of the most valuable aids in diagnosing complex cases of central nervous system infection by dengue virus.

Case Presentation

We report the case of a 35-year-old female from rural West Bengal, India, with expanded dengue syndrome. The patient presented with fever, headaches, body aches, and sudden disorientation over minutes, which progressed to a coma. Neurological examination revealed profound unconsciousness and nuchal rigidity. Laboratory findings were consistent with dengue infection, including altered liver and pancreatic enzyme levels. The diagnosis was facilitated by identifying the "double-doughnut" sign on the brain MRI, which suggested dengue encephalitis. This finding and clinical and serological evidence guided the treatment strategy.

Discussion

The "double-doughnut" sign, though not exclusive to dengue encephalitis, proved crucial in this case, aiding in differentiating from other causes of encephalitis. Recognition of this sign can be pivotal in diagnosing expanded dengue syndrome, facilitating timely and appropriate intervention, and improving patient outcomes. This case also underscores the importance of considering dengue in the differential diagnosis of encephalitis, especially in endemic areas. Also, this case's excellent outcome (both clinically and radiologically) was noteworthy.

Antigenic distance between primary and secondary dengue infections correlates with disease risk

Many pathogens continuously change their protein structure in response to immune-driven selection, resulting in weakened protection even in previously exposed individuals. In addition, for some pathogens, such as dengue virus, poorly targeted immunity is associated with increased risk of severe disease through a mechanism known as antibody-dependent enhancement. However, it remains unclear whether the antigenic distances between an individual's first infection and subsequent exposures dictate disease risk, explaining the observed large-scale differences in dengue hospitalizations across years. Here, we develop a framework that combines detailed antigenic and genetic characterization of viruses with details on hospitalized cases from 21 years of dengue surveillance in Bangkok, Thailand, to identify the role of the antigenic profile of circulating viruses in determining disease risk. We found that the risk of hospitalization depended on both the specific order of infecting serotypes and the antigenic distance between an individual's primary and secondary infections, with risk maximized at intermediate antigenic distances. These findings suggest that immune imprinting helps determine dengue disease risk and provide a pathway to monitor the changing risk profile of populations and to quantifying risk profiles of candidate vaccines.

TV005 dengue vaccine protects against dengue serotypes 2 and 3 in two controlled human infection studies

BACKGROUNDDisease due to dengue viruses is a growing global health threat, causing 100-400 million cases annually. An ideal dengue vaccine should demonstrate durable protection against all 4 serotypes in phase III efficacy trials, however the lack of circulating serotypes may lead to incomplete efficacy data. Controlled human infection models help downselect vaccine candidates and supply critical data to supplement efficacy trials. We evaluated the efficacy of a leading live-attenuated tetravalent dengue vaccine candidate, TV005, against infection with a newly established dengue serotype 3 or an established serotype 2 challenge virus.METHODSTwo randomized, controlled clinical trials were performed. In study 1, a total of 42 participants received TV005 or placebo (n = 21 each), and 6 months later, all were challenged with dengue 2 virus (rDEN2Δ30) at a dose of 103 PFU. In study 2, a total of 23 participants received TV005 and 20 received placebo, and 6 months later, all were challenged with 104 PFU dengue 3 virus (rDEN3Δ30). The study participants were closely monitored for safety, viremia, and immunologic responses. Infection, measured by post-challenge viremia, and the occurrence of rash and neutropenia were the primary endpoints. Secondary endpoints included safety, immunologic, and virologic profiles following vaccination with TV005 and subsequent challenge with the rDEN2Δ30 or rDEN3Δ30 strain.RESULTSTV005 was well tolerated and protected all vaccinated volunteers from viremia with DENV2 or DENV3 (none infected in either group). Placebo recipients had post-challenge viremia (100% in study 1, 85% in study 2), and all experienced rash following challenge with either serotype.CONCLUSIONSTV005 is a leading tetravalent dengue vaccine candidate that fully protected against infection with DENV2 and DENV3 in an established controlled human infection model.TRIAL REGISTRATIONClinicalTrials.gov NCT02317900 and NCT02873260.FUNDINGIntramural Research Program, NIH (contract HHSN272200900010C).

Fatal outcome of dengue fever with multi-organ failure and hemorrhage: A case report

Dengue fever is a prevalent viral disease caused by a single-stranded positive RNA virus belonging to the Flaviviridae family, genus flavivirus. It is characterized by fever, headache, myalgias, leukopenia, rash, and plasma leakage, which may progress to compensated or uncompensated shock and multi-organ failure. Liver involvement is a common feature of Dengue fever and is usually manifested by nausea, vomiting, abdominal discomfort, anorexia, hepatomegaly, and elevated serum transaminase levels. Severe disease is associated with laboratory parameters such as mean Platelet count < 20,000/mm, Aspartate Transaminase Levels >45 IU, and lymphocytes <1500. The Expanded Dengue Syndrome (EDS), a term coined by World Health Organization in 2012, refers to an atypical presentation of Dengue fever that manifests with generalized impacts on normal physiology. This case report presents a 29-year-old male with EDS who presented at a Tertiary Care Hospital in Karachi and died a week later due to liver failure.

Postural fall in systolic blood pressure is a useful warning sign in dengue fever

Background

Capillary leak is the hallmark of development of severe dengue. A rise in haematocrit has been a major warning sign in WHO guidelines. Postural hypotension, which could reflect the intravascular volume reduction in capillary leak has been noted as warning sign in CDC and Pan American Health Organisation guidelines. We evaluated the diagnostic accuracy of postural hypotension as a marker of development of severe dengue.

Methods

150 patients admitted with dengue fever were recruited in this prospective observational study. Diagnostic accuracy of conventional warning signs (abdominal pain, persistent vomiting, fluid accumulation, mucosal bleeding, lethargy, liver enlargement, increasing hematocrit with decreasing platelets) and postural hypotension was evaluated.

Results

23 (15.3%) subjects developed severe dengue. Multiple logistic regression analysis showed that ascites/pleural effusion and postural fall in systolic blood pressure of >10.33% had odds ratio of 5.024(95%CI:1.11 - 22.75) and 11.369 (95% CI:2.27 - 56.87), respectively. Other parameters did not reach statistical significance. Sensitivity and specificity of ascites/pleural effusion were 82.6% and 88.2% for development of severe dengue whereas postural fall in systolic blood pressure had sensitivity and specificity of 87% and 82.7%.

Conclusions

These findings present a strong case for including postural hypotension as a warning sign in patients with dengue fever, especially in resource limited settings.

Dengue hemorrhagic fever: a growing global menace

Dengue virus is an arthropod-borne virus, transmitted by Aedes aegypti among humans. In this review, we discussed the epidemiology of dengue hemorrhagic fever (DHF) as well as the disease's natural history, cycles of transmission, clinical diagnosis, aetiology, prevention, therapy, and management. A systematic literature search was done by databases such as PubMed and Google Scholar using search terms, 'dengue fever', 'symptoms and causes of dengue fever', 'dengue virus transmission', and 'strategies to control dengue'. We reviewed relevant literature to identify hazards related to DHF and the most recent recommendations for its management and prevention. Clinical signs and symptoms of dengue infection range from mild dengue fever (DF) to potentially lethal conditions like DHF or dengue shock syndrome (DSS). Acute-onset high fever, muscle and joint pain, myalgia, a rash on the skin, hemorrhagic episodes, and circulatory shock are among the most common symptoms. An early diagnosis is vital to lower mortality. As dengue virus infections are self-limiting, but in tropical and subtropical areas, dengue infection has become a public health concern. Hence, developing and executing long-term control policies that can reduce the global burden of DHF is a major issue for public health specialists everywhere.

Unforeseen complications: a case of dengue shock syndrome presenting with multi-organ dysfunction in a subtropical region

OVERVIEW

Dengue fever, a viral illness transmitted by the Aedes mosquito, is capable of causing a range of serious complications, including fulminant hepatic failure, renal dysfunction, encephalitis, encephalopathy, neuromuscular and ophthalmic disorders, seizures, and cardiomyopathy.

CASE DESCRIPTION

This report details the case of a 30-year-old lactating woman with no notable medical history who presented to the emergency department with symptoms of high-grade fever, altered mental status, and seizures. Upon imaging, bilateral infarcts in the thalami and cerebellar hemispheres were observed, consistent with cerebellitis and dengue encephalitis.

PATIENT TREATMENT AND OUTCOME

The patient was admitted to the intensive care unit and received appropriate treatment. Following a critical phase and successful patient stabilization, she was transferred to a high dependency unit for a week before being discharged with recommendations for follow-up care.

CONCLUSION

This case illustrates the broad spectrum of complications that can arise as a result of dengue infection and the importance of timely diagnosis and management in improving patient outcomes. Further investigation is required to better understand the mechanisms underlying these complications and to formulate specific guidelines for the prevention and treatment of dengue shock syndrome.

Is new dengue vaccine efficacy data a relief or cause for concern?

Dengue is a major global public health problem requiring a safe and efficacious vaccine as the foundation of a comprehensive countermeasure strategy. Despite decades of attempts, the world has a single dengue vaccine licensed in numerous countries, but restrictions and conditions of its use have deterred uptake. Recently, clinical efficacy data has been revealed for two additional dengue vaccine candidates and the data appears encouraging. In this perspective I discuss dengue, the complexities of dengue vaccine development, early development setbacks, and how the latest data from the field may be cause for measured optimism. Finally, I provide some perspectives on evaluating dengue vaccine performance and how the pursuit of the perfect dengue vaccine may prevent advancement of vaccines which are good enough.

An Extracorporeal Plasma Filtration Column with Specific Binding to Dengue Virions

INTRODUCTION

Dengue infection is a significant public health concern that no specific treatment is available. Extracorporeal plasmapheresis or plasma filtration is a treatment option for severe cases with complications. However, the commercial adsorption devices mainly contained size-exclusive porous beads to adsorb the plasma proteins nonselectively.

METHODS

We developed a 1:50 simulated circuit for dengue virus-specific adsorption using a flavivirus-specific (4G2) antibody entrapped into the alginate bead.

RESULTS

The reduction ratios of the viral titer after 3 h of continuous run were 63.00 ± 1.21%, and 93.97 ± 1.27% measured by reverse transcription qPCR, and plaque titration, respectively. No specific adsorption was observed with Enterovirus A71 or Escherichia coli bacteria.

CONCLUSION

This study is a proof-of-concept for the potential use of a dengue virus-specific adsorption column in the 1:50 simulated circuit. The system could be applied to various clinical platforms by substituting target-specific antibodies.

Fluid management in children with severe dengue: a narrative review

Dengue is a mosquito-borne arboviral infection of increasing public health importance. Globally, children account for a significant proportion of infections. No pathogen-specific treatment currently exists, and the current approach to reducing disease burden is focused on preventative strategies such as vector control, epidemiological interventions, and vaccination in selected populations. Once infected, the mainstay of treatment is supportive, of which appropriate fluid management is a cornerstone. The timely provision of fluid boluses has historically been central to the management of septic shock. However, in patients with dengue shock, particular emphasis is placed on judicious fluid administration. Certain colloids such as hydroxyethyl starches and dextran, despite no longer being used routinely in intensive care units due to concerns of acute kidney injury and impairment of coagulation, are still commonly used in dengue shock syndrome. Current guidelines recommend initial crystalloid therapy, with consideration of colloids for severe or recalcitrant shock in patients with dengue. In this review, we discuss the pathophysiology of septic shock, and consider whether any differences in dengue exist that may warrant a separate approach to fluid therapy. We critically review the available evidence for fluid management in dengue, including the role of colloids. In dengue, there is increasing recognition of the importance of tailoring fluid therapy to phases of disease, with attention to the need for fluid "deresuscitation" once the critical phase of vascular leak passes.

World Dengue Day: A call for action

Commemorating the 2021 ASEAN Dengue Day and advocacy for World Dengue Day, the International Society for Neglected Tropical Diseases (ISNTD) and Asian Dengue Voice and Action (ADVA) Group jointly hosted the ISNTD-ADVA World Dengue Day Forum–Cross Sector Synergies in June 2021. The forum aimed to achieve international and multisectoral coordination to consolidate global dengue control and prevention efforts, share best practices and resources, and improve global preparedness. The forum featured experts around the world who shared their insight, research experience, and strategies to tackle the growing threat of dengue. Over 2,000 healthcare care professionals, researchers, epidemiologists, and policy makers from 59 countries attended the forum, highlighting the urgency for integrated, multisectoral collaboration between health, environment, education, and policy to continue the march against dengue. Sustained vector control, environmental management, surveillance improved case management, continuous vaccine advocacy and research, capacity building, political commitment, and community engagement are crucial components of dengue control. A coordinated strategy based on science, transparency, timely and credible communication, and understanding of human behavior is needed to overcome vaccine hesitancy, a major health risk further magnified by the COVID-19 pandemic. The forum announced a strong call to action to establish World Dengue Day to improve global awareness, share best practices, and prioritize preparedness in the fight against dengue.

The growing threat of dengue poses a significant public health burden endangering the well-being and socioeconomic development of many countries across the world. The International Society for Neglected Tropical Diseases (ISNTD) and Asian Dengue Voice and Action (ADVA) group brought together the collaborative efforts of healthcare care professionals, researchers, epidemiologists, environmentalists, and policy makers to coordinate international dengue control strategy. A strong call to action to establish a World Dengue Day was announced to improve global awareness, share best practices, and prioritize preparedness in the fight against dengue. The World Dengue Day highlighted the need for all governments, healthcare professionals, civil societies, public and private sectors, schools and universities, and citizens in dengue-endemic countries to form a strong coalition to encourage and accelerate a collective dengue control response.

Expanded dengue syndrome presenting with acute liver failure, acute kidney injury, pancreatic involvement, coagulopathy, and multiple intracranial hemorrhages in a young child: a case report

Background

Dengue is a mosquito-borne viral infection that typically occurs in tropical and subtropical countries. The clinical manifestations of dengue infection range from an asymptomatic subclinical course to severe dengue shock syndrome. Besides, dengue can affect any organ in the body and can present with atypical manifestations.

Case presentation

We report a 6-year-old previously healthy Tamil child who had dengue complicated with multiorgan involvement. She initially presented with high fever, headache, body aches for 5 days, blood and mucus diarrhea, hematuria, and right knee joint swelling for 2 days. Dengue NS1 antigen was positive on day 2 of febrile illness. She was managed symptomatically in the local hospital for 3 days and transferred to the tertiary care hospital for further management. She was eventually diagnosed as having dengue hemorrhagic fever complicated with multiorgan involvement including acute liver failure, pancreatic involvement, coagulopathy, arthritis, acute kidney injury, and multiple intracranial hemorrhages. The constellation of disease manifestations was identified as expanded dengue syndrome. She was managed with fresh blood, platelet, and cryoprecipitate transfusions and intravenous antibiotics in addition to renal and liver support in the intensive care unit. On day 14 of illness, she deteriorated while on the ventilator and died due to multiple intracranial hemorrhages.

Conclusion

The reported child with dengue hemorrhagic fever developed several unusual presentations such as acute liver and renal failure, disseminated intravascular coagulopathy, pancreatic involvement, and multiple intracranial hemorrhages, which form part of expanded dengue syndrome. In the seriously unwell child, it is important to look for unusual complications actively to improve outcomes.

SARS-CoV-2/DENV co-infection: a series of cases from the Federal District, Midwestern Brazil

Background

Since the novel coronavirus disease outbreak, over 179.7 million people have been infected by SARS-CoV-2 worldwide, including the population living in dengue-endemic regions, particularly Latin America and Southeast Asia, raising concern about the impact of possible co-infections.

Methods

Thirteen SARS-CoV-2/DENV co-infection cases reported in Midwestern Brazil between April and September of 2020 are described. Information was gathered from hospital medical records regarding the most relevant clinical and laboratory findings, diagnostic process, therapeutic interventions, together with clinician-assessed outcomes and follow-up.

Results

Of the 13 cases, seven patients presented Acute Undifferentiated Febrile Syndrome and six had pre-existing co-morbidities, such as diabetes, hypertension and hypopituitarism. Two patients were pregnant. The most common symptoms and clinical signs reported at first evaluation were myalgia, fever and dyspnea. In six cases, the initial diagnosis was dengue fever, which delayed the diagnosis of concomitant infections. The most frequently applied therapeutic interventions were antibiotics and analgesics. In total, four patients were hospitalized. None of them were transferred to the intensive care unit or died. Clinical improvement was verified in all patients after a maximum of 21 days.

Conclusions

The cases reported here highlight the challenges in differential diagnosis and the importance of considering concomitant infections, especially to improve clinical management and possible prevention measures. Failure to consider a SARS-CoV-2/DENV co-infection may impact both individual and community levels, especially in endemic areas.

Knowledge gaps in the epidemiology of severe dengue impede vaccine evaluation

The most severe consequences of dengue virus infection include shock, haemorrhage, and major organ failure; however, the frequency of these manifestations varies, and the relative contribution of pre-existing anti-dengue virus antibodies, virus characteristics, and host factors (including age and comorbidities) are not well understood. Reliable characterisation of the epidemiology of severe dengue first depends on the use of consistent definitions of disease severity. As vaccine trials have shown, severe dengue is a crucial interventional endpoint, yet the infrequency of its occurrence necessitates the inclusion of thousands of study participants to appropriately compare its frequency among participants who have and have not been vaccinated. Hospital admission is frequently used as a proxy for severe dengue; however, lack of specificity and variability in clinical practices limit the reliability of this approach. Although previous infection with a dengue virus is the best characterised risk factor for developing severe dengue, the influence of the timing between dengue virus infections and the sequence of dengue virus infections on disease severity is only beginning to be elucidated. To improve our understanding of the diverse factors that shape the clinical spectrum of disease resulting from dengue virus infection, prospective, community-based and clinic-based immunological, virological, genetic, and clinical studies across a range of ages and geographical regions are needed.

Comparing machine learning with case-control models to identify confirmed dengue cases

In recent decades, the global incidence of dengue has increased. Affected countries have responded with more effective surveillance strategies to detect outbreaks early, monitor the trends, and implement prevention and control measures. We have applied newly developed machine learning approaches to identify laboratory-confirmed dengue cases from 4,894 emergency department patients with dengue-like illness (DLI) who received laboratory tests. Among them, 60.11% (2942 cases) were confirmed to have dengue. Using just four input variables [age, body temperature, white blood cells counts (WBCs) and platelets], not only the state-of-the-art deep neural network (DNN) prediction models but also the conventional decision tree (DT) and logistic regression (LR) models delivered performances with receiver operating characteristic (ROC) curves areas under curves (AUCs) of the ranging from 83.75% to 85.87% [for DT, DNN and LR: 84.60% ± 0.03%, 85.87% ± 0.54%, 83.75% ± 0.17%, respectively]. Subgroup analyses found all the models were very sensitive particularly in the pre-epidemic period. Pre-peak sensitivities (<35 weeks) were 92.6%, 92.9%, and 93.1% in DT, DNN, and LR respectively. Adjusted odds ratios examined with LR for low WBCs [≤ 3.2 (x103/μL)], fever (≥38°C), low platelet counts [< 100 (x103/μL)], and elderly (≥ 65 years) were 5.17 [95% confidence interval (CI): 3.96-6.76], 3.17 [95%CI: 2.74-3.66], 3.10 [95%CI: 2.44-3.94], and 1.77 [95%CI: 1.50-2.10], respectively. Our prediction models can readily be used in resource-poor countries where viral/serologic tests are inconvenient and can also be applied for real-time syndromic surveillance to monitor trends of dengue cases and even be integrated with mosquito/environment surveillance for early warning and immediate prevention/control measures. In other words, a local community hospital/clinic with an instrument of complete blood counts (including platelets) can provide a sentinel screening during outbreaks. In conclusion, the machine learning approach can facilitate medical and public health efforts to minimize the health threat of dengue epidemics. However, laboratory confirmation remains the primary goal of surveillance and outbreak investigation.

High sensitivity of one-step real-time reverse transcription quantitative PCR to detect low virus titers in large mosquito pools

Background

Mosquitoes are the deadliest animals in the world. Their ability to carry and spread diseases to humans causes millions of deaths every year. Due to the lack of efficient vaccines, the control of mosquito-borne diseases primarily relies on the management of the vector. Traditional control methods are insufficient to control mosquito populations. The sterile insect technique (SIT) is an additional control method that can be combined with other control tactics to suppress specific mosquito populations. The SIT requires the mass-rearing and release of sterile males with the aim to induce sterility in the wild female population. Samples collected from the environment for laboratory colonization, as well as the released males, should be free from mosquito-borne viruses (MBV). Therefore, efficient detection methods with defined detection limits for MBV are required. Although a one-step reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) method was developed to detect arboviruses in human and mosquito samples, its detection limit in mosquito samples has yet to be defined.

Methods

We evaluated the detection sensitivity of one step RT-qPCR for targeted arboviruses in large mosquito pools, using pools of non-infected mosquitoes of various sizes (165, 320 and 1600 mosquitoes) containing one infected mosquito body with defined virus titers of chikungunya virus (CHIKV), usutu virus (USUV), West Nile virus (WNV) and Zika virus (ZIKV).

Results

CHIK, USUV, ZIKV, and WNV virus were detected in all tested pools using the RT-qPCR assay. Moreover, in the largest mosquito pools (1600 mosquitoes), RT-qPCR was able to detect the targeted viruses using different total RNA quantities (10, 1 and 0.1 ng per reaction) as a template. Correlating the virus titer with the total RNA quantity allowed the prediction of the maximum number of mosquitoes per pool in which the RT-qPCR can theoretically detect the virus infection.

Conclusions

Mosquito-borne viruses can be reliably detected by RT-qPCR assay in pools of mosquitoes exceeding 1000 specimens. This will represent an important step to expand pathogen-free colonies for mass-rearing sterile males for programmes that have a SIT component by reducing the time and the manpower needed to conduct this quality control process.

Capture-Layer Lateral Flow Immunoassay: A New Platform Validated in the Detection and Quantification of Dengue NS1

The lateral flow immunoassay (LFIA) is the most successful point-of-care testing (POCT) method to date. In the case of clinical biomarkers that require quantification, it remains a challenge to quantitate those biomarkers using the lateral flow immunoassay remains a challenge due to the cost of the reader and possibly the type of marker used. In the present work, a new concept of a platform LFIA device configuration is proposed in which different, aligned membrane components, some already existing in the classical lateral flow immunoassay, and the others created with special new functions in the present device. As the sample containing the target analyte passes through the aforementioned membranes, the target analyte will initially interact with a target-specific antibody-conjugated to horseradish peroxidase (HRP). Thereafter, the newly formed immunocomplex will diffuse through a proprietary capture membrane (that ensures that the nontarget-bound antibodies do not continue further and thus remain "captured" to that specific area). This is done by having the target molecules (or components thereof) immobilized onto the said capture layer. The target-bound immunocomplexes will then be allowed by the system configuration to continue further to the last layer, where the signal will be generated and quantified. Thus, in the absence of the target analyte in the sample, the free antibodies will be filtered at the capture layer by preimmobilized analyte molecules, thus preventing a false positive signal to occur. We validated the concept in the detection of dengue NS1 protein in view of making a triage test. The sample containing NS1 will first meet HRP-conjugated NS1-specific antibodies and become attached, thus producing an NS1-specific antibody-HRP immunocomplex. The sample then flows through the blocking layer, where the immunocomplex is unchallenged and thus allowed to reach the last "absorbent" pad, incorporating the substrate for the HRP marker. In the case of a positive test, a signal is generated, that is proportional to the amount of immunocomplexes (and therefore the NS1 concentration), and then analyzed and measured at the absorbent pad. Any unbound anti-NS1 antibody will be stopped at the blocking matrix by preimmobilized NS1, so there will be no false positive. As this study is the initial study of a novel configuration, much of the work comprised of optimization steps, such as determining the required NS1 membrane-immobilization concentration and the required target-specific capture antibody concentration. Our immunoassay was tested with spiked buffer and serum samples to mimic the clinical conditions, with a range of NS1 concentrations, and was found, at this time, to be fivefold more sensitive than a gold standard enzyme-linked immunosorbent assay (ELISA) test (5 ng mL^-1) performed in our laboratory. This method shows another form of LFIA that has the potential to be quantitative (at least semiquantitative), albeit not solving the reader cost; however, unlike the regular LFIA, we do not use nanobeads but instead enzymes, allowing, in theory, greater sensitivity, while retaining the one-step procedure. The test is accurate and has low production costs.

Diagnosis of severe dengue: Challenges, needs and opportunities

BACKGROUND

Delayed diagnosis of dengue cases with increased risk for severe disease could lead to poor disease outcome. To date there is no specific laboratory diagnostic test for severe dengue. This qualitative study explored expert views regarding current issues in diagnosing severe dengue, rationale for severe dengue-specific diagnostics, future prospects and features of potential diagnostics for severe dengue.

METHODS

In-depth individual interviews with thematic saturation were conducted between May and July 2018. The data was analyzed using thematic analysis.

RESULTS

Based on expert opinion, diagnosis of severe dengue is challenging as it depends on astute clinical interpretation of non-dengue-specific clinical and laboratory findings. A specific test that detects impending manifestation of severe dengue could 1) overcome failure in identifying severe disease for referral or admission, 2) facilitate timely and appropriate management of plasma leakage and bleeding, 3) overcome the lack of clinical expertise and laboratory diagnosis in rural health settings. The most important feature of any diagnostics for severe dengue is the point-of-care (POC) format where it can be performed at or near the bedside.

CONCLUSION

The development of diagnostics to detect impending severe dengue is warranted to reduce the morbidity and mortality rates of dengue infection and it should be prioritized.

Towards Predicting Progression to Severe Dengue

There is an urgent need for prognostic assays to predict progression to severe dengue infection, which is a major global threat. While the majority of symptomatic dengue patients experience an acute febrile illness, 5-20% progress to severe infection associated with significant morbidity and mortality. Early monitoring and administration of supportive care reduce mortality and clinically usable biomarkers to predict severe dengue are needed. Here, we review recent discoveries of gene sets, anti-dengue antibody properties, and inflammatory markers with potential utility as predictors of disease progression. Upon larger scale validation and development of affordable sample-to-answer technologies, some of these biomarkers may be utilized to develop the first prognostic assay for improving patient care and allocating healthcare resources more effectively in dengue endemic countries.

A favorable outcome of dengue hemorrhagic fever despite poor prognostic indices: a case report with a mix of classic and unusual clinical and laboratory features

The report describes a 32-year-old man with dengue hemorrhagic fever presenting with acute onset high-grade intermittent fever with chills and rigors, headache, myalgia, abdominal pain, and vomiting. His laboratory results revealed neutrophilia, thrombocytopenia, microscopic hematuria, and a markedly elevated D-dimer. While on admission, he developed diarrhea, hypertension, and respiratory symptoms which evolved into respiratory distress with low oxygen saturation, eventually warranting his admission to the Intensive Care Unit (ICU). Despite his adverse prognostic indices, the patient made an uneventful recovery with conservative management after 16 days of admission. Thus illustrating how aggressive management could influence the outcome of dengue illness.

Dengue infection and advances in dengue vaccines for children

Dengue viruses are endemic in most tropical and subtropical countries where they produce disease ranging from a mild fever to a severe, potentially fatal vascular permeability syndrome. We reviewed the status of development and testing in children of three vaccines designed to protect against the four dengue viruses. The first dengue virus vaccine, Dengvaxia, now licensed in 20 endemic countries, the EU and the USA, provides protection against severe dengue in seropositive individuals but increases the risk for naive recipients to develop severe dengue and to be hospitalised. We discuss mechanisms and implications of shortcomings of the licensed vaccine and describe the structure and attributes of two other dengue virus vaccines. Based upon human dengue challenge studies, one of these vaccines promises to deliver solid, long-lasting immunity after a single dose. Because dengue virus infections are ubiquitous in residents and visitors to tropical countries, in the absence of a protective vaccine paediatricians should recognise the early signs and clinical presentation of severe dengue, understand its pathophysiology and appropriate management.

Role of Interleukin-10 and Abdominopelvic Ultrasound as a Potential Predictor of Disease Severity in Dengue Hemorrhagic Fever

Introduction

Dengue viral infections are a major cause of morbidity and mortality in tropical/subtropical countries. Early and prompt detection of dengue hemorrhagic fever (DHF), though challenging, is helpful to identify an individual that would benefit from intensive therapy.

Objective

The goal of this study was to determine the plasma interleukin-10 (IL-10) levels in DHF patients at four to seven days of disease onset and 24 hours after the first sample. We also aimed to determine the association of plasma IL-10 levels and abdominopelvic ultrasound findings.

Methods

A total of 50 registered DHF patients aged 15 to 50 years were recruited. Plasma IL-10 concentration measurements and abdominopelvic ultrasounds were performed. Patients were also categorized based on ultrasound grading I to IV (based on severity). Outcomes were described as recovery and shock. Platelet count and hematocrit percentages were also recorded.

Results

Plasma IL-10 levels were elevated in DHF patients and associated with fatal outcomes (p = 0.00). Binary regression-coefficient showed the direct effect of high levels of plasma IL-10 on the fatal outcome of patients 24 hours after the first sample (p = 0.04). Disease severity was predicted by a positive correlation between ultrasound grades and outcomes (p = 0.00). Spearman’s correlation coefficient found a highly significant inverse relationship between plasma IL-10 levels and platelet count after 24 hours (p = 0.01). However, a significant positive relationship was observed between elevated plasma IL-10 levels and hematocrit percentage after 24 hours (p = 0.01).

Conclusion

Elevated plasma IL-10 levels and abdominopelvic ultrasonography are promising potential predictors of disease progression and fatal outcome in DHF patients.

Safety and costs of blood transfusion practices in dengue cases in Brazil

Background

Dengue is a public health problem, and noncompliance with World Health Organization (WHO) recommendations for blood transfusion components is frequently reported. Moreover, economic impact studies of the WHO recommendations on the use of blood transfusion are scarce.

Methods

We compared the cost and hospitalization time in a prospective observational study, by following hospitalised patients and analysing their medical records from 2010 and March 2016 to December 2017. We divided the patients into two groups: transfused (with or without WHO criteria for transfusion) and not transfused (with or without WHO criteria for transfusion). Generalised linear modelling was performed to identify the variable that could increase the costs and hospital stay.

Results

Among 323 patients, 52 were transfused, of whom 52% without criteria (n = 27), and 271 were not transfused, of which 4.4% (n = 12) with criteria. Hospitalisation costs were 41% higher in the transfused group without criteria than in those with criteria (median US$ 674.3 vs US$ 478 p = 0.293). Patients who were not transfused but met the WHO criteria for transfusion (n = 12) had longer mean hospitalisation time than did those who were not transfused (3.8±3.4 days versus 3.6±3.1 days; p = 0.022). The GLM analysis using hospital stay and costs as the dependent variable explained approximately 33.4% (R² = 0.334) of the hospitalisation time and 79.3% (R² = 0.793) of costs. Receiving a transfusion increased the hospitalization time by 1.29 days (p = 0.0007; IRR = 1.29), and the costs were 5.1 times higher than those without receiving blood components (IRR = 5.1; p< 0.001; median US$ 504.4 vs US$ 170.7). In contrast, patients who were transfused according to WHO criteria had a reduction in costs of approximately 96% (IRR = 0.044; p<0.001; β = -3.12) compared to that for those who were not transfused according to WHO criteria (without criteria).

Conclusion

Transfusion without following WHO recommendations increased the time and cost of hospitalisation.

An algorithm applied to national surveillance data for the early detection of major dengue outbreaks in Cambodia

Dengue is a national priority disease in Cambodia. The Cambodian National Dengue Surveillance System is based on passive surveillance of dengue-like inpatients reported by public hospitals and on a sentinel, pediatric hospital-based active surveillance system. This system works well to assess trends but the sensitivity of the early warning and time-lag to usefully inform hospitals can be improved. During The ECOnomic development, ECOsystem MOdifications, and emerging infectious diseases Risk Evaluation (ECOMORE) project's knowledge translation platforms, Cambodian hospital staff requested an early warning tool to prepare for major outbreaks. Our objective was therefore to find adapted tools to improve the early warning system and preparedness. Dengue data was provided by the National Dengue Control Program (NDCP) and are routinely obtained through passive surveillance. The data were analyzed at the provincial level for eight Cambodian provinces during 2008-2015. The R surveillance package was used for the analysis. We evaluated the effectiveness of Bayesian algorithms to detect outbreaks using count data series, comparing the current count to an expected distribution obtained from observations of past years. The analyses bore on 78,759 patients with dengue-like syndromes. The algorithm maximizing sensitivity and specificity for the detection of major dengue outbreaks was selected in each province. The overall sensitivity and specificity were 73% and 97%, respectively, for the detection of significant outbreaks during 2008-2015. Depending on the province, sensitivity and specificity ranged from 50% to 100% and 75% to 100%, respectively. The final algorithm meets clinicians' and decisionmakers' needs, is cost-free and is easy to implement at the provincial level.

A 20-Gene Set Predictive of Progression to Severe Dengue

There is a need to identify biomarkers predictive of severe dengue. Single-cohort transcriptomics has not yielded generalizable results or parsimonious, predictive gene sets. We analyzed blood samples of dengue patients from seven gene expression datasets (446 samples, five countries) using an integrated multi-cohort analysis framework and identified a 20-gene set that predicts progression to severe dengue. We validated the predictive power of this 20-gene set in three retrospective dengue datasets (84 samples, three countries) and a prospective Colombia cohort (34 patients), with an area under the receiver operating characteristic curve of 0.89, 100% sensitivity, and 76% specificity. The 20-gene dengue severity scores declined during the disease course, suggesting an infection-triggered host response. This 20-gene set is strongly associated with the progression to severe dengue and represents a predictive signature, generalizable across ages, host genetic factors, and virus strains, with potential implications for the development of a host response-based dengue prognostic assay.

Challenges and opportunities in controlling mosquito-borne infections

Mosquito-borne diseases remain a major cause of morbidity and mortality across the tropical regions. Despite much progress in the control of malaria, malaria-associated morbidity remains high, whereas arboviruses-most notably dengue-are responsible for a rising burden of disease, even in middle-income countries that have almost completely eliminated malaria. Here I discuss how new interventions offer the promise of considerable future reductions in disease burden. However, I emphasize that intervention programmes need to be underpinned by rigorous trials and quantitative epidemiological analyses. Such analyses suggest that the long-term goal of elimination is more feasible for dengue than for malaria, even if malaria elimination would offer greater overall health benefit to the public.