Dengue hemorrhagic fever: clinical manifestations and management

Myopic Shift in a Patient with Dengue Fever

PURPOSE

This report aims to present a case of dengue-related myopic shift.

METHODS

This is a case report of a patient with dengue-related transient myopia, and demonstrates possible underlying pathophysiology.

RESULTS

A 38-year-old gentleman presented with bilateral blurring of vision with an unaided visual acuity (VA) of 6/120 bilaterally. He had a refractive error of -2.50 dioptres in the right eye, and -3.50 dioptres in the left eye. Ultrasound biomicroscopy (UBM) revealed suprachoroidal effusion with anterior displacement of the lens-iris complex bilaterally. Biometry performed showed lens thickness (LT) of 4.47 mm in the right eye, and 4.65 mm in the left eye. His unaided VA was noted to be 6/6 bilaterally 4 days later.

CONCLUSIONS

Dengue-related myopic shift was likely secondary to two mechanisms. Firstly, suprachoroidal effusion resulted in an anterior displacement of the lens-iris complex. Secondly, there was an increase in the antero-posterior diameter of the lens, resulting in index myopia.

Occurrence of Dengue Virus Infection with Multiple Serotypes at Central Karnataka, India

Objective To find the incidence of concurrent infection of dengue and correlate the difference in clinical features, laboratory diagnoses, and outcomes between dengue and dengue-like illnesses.

Methodology A total of 2,256 patients with suspected dengue fever during the period of July 2014 to June 2020 as per the WHO case definition for dengue fever were enrolled in the study. All patients admitted with a suspected dengue fever were studied in detail in terms of demographic features, clinical features, and laboratory profiles. Two blood samples were collected from each patient with a history of fever for 5 to 7 days. Investigation consisted of CBC, Widal test, malarial card test, Weil Felix test, Scrub typhus test, chikungunya, dengue parameters such as dengue NS1, IgM, and IgG, and real-time PCR for dengue serotypes were performed for each sample.

Results A total of 1,412 males (62.6%) and 844 females (37.4%) of age 2 to 44 years were hospitalized. Out of 2,256 clinically suspected dengue cases, 1,306 cases were positive and 950 were negative by RT-PCR test. Fever was the most common clinical features among the RT-PCR-positive cases, followed by retroorbital pain (85.9%), flushing in 77.5%, and rashes in 84.8% of patients. ARDS was seen in 9.7% and splenomegaly in 27.5% patients. A platelet count of less than 100,000 was observed in 1,838 (81.5%) patients, and a platelet count of less than 20,000 was observed in 147 (6.5%) patients.

Of 2,256 samples, 1,306 (57.9%) tested positive for dengue viral RNA by RT-PCR. Also, 798 cases were infected with a single DENV serotype, and 608 had a concurrent infection. Of the 798 single DENV serotype infection cases, 392 (54.2%) were typed as DENV-2 and 218 (29.2%) as DENV-3. Coinfection with serotypes DENV-2 and DENV-3 was found to account for 67.8% of all concurrent infections.

Conclusion The study showed that dengue fever with concurrent infection with multiple serotypes is on the rise, and an occurrence of recombination may lead to the emergence of more virulent strains showing varied clinical presentations.

Coagulopathy in SARS-CoV-2 Infected Patients: Implication for the Management of COVID-19

COVID-19 disease has led to an extraordinary inclusive health crisis globally. Elevation of D-dimer is the major remarkable abnormal coagulation test in seriously ill COVID-19 patients. In nearly 50% of COVID-19 patients, the value of D-dimer was significantly enhancing. Recent literature indicated that COVID-19 patients were at higher risk of developing disseminated intravascular coagulation. Pro-inflammatory cytokines and chemokines are some of the factors leading to these conditions. The majority of COVID-19 patients showed a higher profile of pro-inflammatory cytokines and chemokines in severe clinical conditions. Tumor necrosis factor-α (TNF-α) and interleukins (ILs) elevated in COVID-19 infected patients. TNF-α, IL-6, and IL-1 are major cytokines vital for the inhibition of intrinsic anticoagulant pathways. COVID-19 becomes a higher complication with a significant effect on blood cell production and hemostasis cascades. Deep vein thrombosis and arterial thrombosis are common complications. Changes in hematological parameters are also frequently observed in COVID-19 patients. Especially, thrombocytopenia is an indicator for poor prognosis of the disease and is highly expected and aggravates the likelihood of death of SARS-CoV-2 infected individuals. Thrombopoiesis reduction in COVID-19 patients might be due to viral abuse of the bone marrow/the viral load may affect thrombopoietin production and function. In other ways, immune-inflammation-mediated destruction and increased consumption of platelets are also the possible proposed mechanisms for thrombocytopenia. Therefore, the counting of platelet cells is an easily accessible biomarker for disease monitoring. All SARS-CoV-2 infected patients should be admitted and identifying potential higher-risk patients. It is also obligatory to provide appropriate treatments with intensive care and strict follow-up. In addition, considerations of chronic diseases are essential for better prognosis and recovery. The current review discusses coagulopathy among SARS-CoV-2 infected individuals and its complication for the management of the disease.

Immunological and Pathological Landscape of Dengue Serotypes 1-4 Infections in Immune-Competent Mice

Dengue virus (DENV), a Flavivirus, causes a broad spectrum of disease in humans with key clinical signs including thrombocytopenia, vascular leakage and hemorrhaging. A major obstacle to understanding DENV immunity has been the lack of a validated immune-competent mouse model. Here, we report the infection profiles of human clinical isolates of DENV serotypes 1-4 in an immune-competent mouse model. We detected replicating DENV in the peritoneal cells, liver and the spleen that was generally resolved within 2 weeks. The DENV target cell types for infection were monocytes/macrophages, dendritic cells, endothelial cells, and we identified a novel DENV cellular target, fibroblast reticular cells of the spleen. We observed gross pathologies in the spleen and liver that are consistent with dengue disease, including hemorrhaging as well as transcriptional patterns suggesting that antiviral responses and tissue damage were induced. Key clinical blood parameters that define human DENV disease such as hemoconcentration, leukopenia and reduced number of platelets were also observed. Thus, immune-competent mice sustain replicating infection and experience signs, such as hemorrhaging, that define DENV disease in humans. This study thoroughly characterizes DENV1-4 infection in immune-competent mice and confirms the wild-type mouse model as a valid and reproducible system for investigating the mechanisms of DENV pathogenesis.

Serum chymase levels correlate with severe dengue warning signs and clinical fluid accumulation in hospitalized pediatric patients

Dengue induces a spectrum of severity in humans from the milder dengue fever to severe disease, or dengue hemorrhagic fever (DHF). Chymase is a candidate biomarker that may aid dengue prognosis. This prospective study aimed to identify whether warning signs of severe dengue, including hypovolemia and fluid accumulation, were associated with elevated chymase. Serum chymase levels were quantified prospectively and longitudinally in hospitalized pediatric dengue patients in Sri Lanka. Warning signs were determined based on daily clinical assessments, laboratory tests and ultrasound findings. Chymase was significantly elevated during the acute phase of disease in DHF or Severe dengue, defined by either the 1997 or 2009 WHO diagnosis guidelines, and persisted longer in the most severe patients. Chymase levels were higher in patients with narrow pulse pressure and clinical warning signs such as severe leakage, fluid accumulation, pleural effusion, gall-bladder wall thickening and rapid haematocrit rise concurrent with thrombocytopenia. No association between chymase and liver enlargement was observed. This study confirms that serum chymase levels are associated with DHF/Severe dengue disease in hospitalized pediatric patients. Chymase levels correlate with warning signs of vascular dysfunction highlighting the possible functional role of chymase in vascular leakage during dengue.

The mechanistic role of antibodies to dengue virus in protection and disease pathogenesis

INTRODUCTION

Dengue is a prevalent disease in tropical and subtropical countries with an estimated 400 million people infected annually. While significant advancement has been made in the chase for an effective dengue vaccine, the recently licensed Sanofi vaccine was, in contrast to in vitro data, only partially protective. Areas covered: This suggests that our understanding of the serological correlates for dengue is currently inadequate. With growing evidence supporting the role of fragment crystalizable gamma receptors (FcγRs) in antibody-mediated neutralization or antibody-dependent enhancement (ADE) of dengue virus (DENV) infection, FcγR-expressing cells have been increasingly used for measuring neutralizing antibody responses elicited by dengue vaccines. Here, we review the mechanisms of how FcγRs modulates both DENV neutralization and enhanced infections via its interactions with antibodies. Expert commentary: This review provides insights on the importance of factoring FcγRs for in vitro neutralization assays. Bridging the gap between in vitro and clinical observations would allow researchers to more accurately predict in vivo vaccine efficacy.

Furosemide infusion in children with dengue fever and hypoxemia

Objectives

To study the role of furosemide infusion in the management of Acute respiratory distress syndrome (ARDS) associated with dengue fever.

Methods

Children between the ages of 1 month to 18 years, who fulfilled the WHO clinical criteria for dengue infection and American European Consensus Criteria criteria for ARDS with Dengue IgM positivity, were evaluated. Patients were studied as group D (receiving diuretic therapy alone) and group B (both ventilation and diuretics), and compared to a historical control group V (ventilation alone). Furosemide infusion was administered at 0.05–0.1 mg/kg/hour for 48 hours, maintaining a urine output of 2–4 mL/kg/hour.

Results

There was a significant difference in survival in the three groups. Significant difference was noted between pre- and postintervention arterial blood gases with respect to PCO₂ (P=0.02), pO₂ (P=0.003), PaO₂/FaO₂ ratio (P<0.001) and alveolar-arteriolar oxygen gradient (P=0.002).

Conclusion

Diuretic infusion improves outcome in dengue with ARDS.

Augmented miR-150 expression associated with depressed SOCS1 expression involved in dengue haemorrhagic fever

OBJECTIVE

Suppressors of cytokine signalling (SOCS) proteins regulate cytokine responses and control immune balance. The objective of our study was to determine whether the expression of SOCS1 and its potential regulatory microRNAs (miRNAs) in leukocytes is correlated to the development of dengue haemorrhagic fever (DHF).

METHODS

We performed a case-control study to investigate the SOCS1 and miRNA expression in leukocytes for patients with DF and DHF in a DENV-2 outbreak that occurred in Taiwan between 2002 and 2003. We performed reverse transcription polymerase chain reaction to evaluate the expression of SOCS1 and its regulatory miRNAs in mononuclear leukocytes obtained from patients with or without DHF. The reciprocal relationship between SOCS1 and miR-150 expression was validated in DENV-2-infected peripheral mononuclear cells (PBMCs).

RESULTS

SOCS1 expression and lower IFN-γ level were significantly reduced in DHF patients, but not in patients with DF. Elevated SOCS1 and reduced miR-150 levels were detected 24 h after DENV-2 infection in PBMCs. Transfection of a miR-150 mimic into CD14(+) cells infected with DENV-2 suppressed the induction of SOCS1 expression in a dose-dependent manner.

CONCLUSION

We demonstrate for the first time that augmented miR-150 expression with depressed SOCS1 expression in CD14(+) cells are associated with the pathogenesis of DHF.

A novel dengue virus detection method that couples DNAzyme and gold nanoparticle approaches

Background

Recent epidemics of dengue viruses (DENV) coupled with new outbreaks on the horizon have renewed the demand for novel detection methods that have the ability to identify this viral pathogen prior to the manifestation of symptoms. The ability to detect DENV in a timely manner is essential for rapid recovery from disease symptoms. A modified lab-derived 10-23 DNAzyme tethered to gold nanoparticles provides a powerful tool for the detection of viruses, such as DENV.

Results

We examined the effectiveness of coupling DNAzyme (DDZ) activation to the salt-induced aggregation of gold nanoparticles (AuNP) to detect dengue virus (DENV) progeny in mosquito cells. A DNAzyme was designed to recognize the 5’ cyclization sequence (5’ CS) that is conserved among all DENV, and conjugated to AuNPs. DDZ-AuNP has demonstrated the ability to detect the genomic RNA of our model dengue strain, DENV-2 NGC, isolated from infected Aedes albopictus C6/36 cells. These targeting events lead to the rapid aggregation of AuNPs, resulting in a red to clear color transition of the reaction mixes, and thus positive detection of the DENV RNA genome. The inclusion of SDS in the reaction mixture permitted the detection of DENV directly from cell culture supernatants without additional sample processing. Specificity assays demonstrated detection is DENV-specific, while sensitivity assays confirm detection at levels of 1 × 10¹ TCID50 units. These results demonstrate DDZ-AuNP effectively detects DENV genomes in a sequence specific manner and at concentrations that are practical for field use.

Conclusions

We have developed an effective detection assay using DNAzyme catalysis coupled with AuNP aggregation for the detection of DENV genomes in a sequence specific manner. Full development of our novel DDZ-AuNP detection method will provide a practical, rapid, and low cost alternative for the detection of DENV in mosquito cells and tissues, and possibly infected patient serum, in a matter of minutes with little to no specialized training required.

The pathogenesis of dengue

Dengue is an important cause of childhood and adult morbidity in Asian and Latin American countries and its geographic footprint is growing. The clinical manifestations of dengue are the expression of a constellation of host and viral factors, some acquired, others intrinsic to the individual. The virulence of the virus plus the flavivirus infection history, age, gender and genotype of the host all appear to help shape the severity of infection. Similarly, the characteristics of the innate and acquired host immune response subsequent to infection are also likely determinants of outcome. This review summarises recent developments in the understanding of dengue pathogenesis and their relevance to dengue vaccine development.

Mouse STAT2 restricts early dengue virus replication

Dengue virus encodes several interferon antagonists. Among these the NS5 protein binds STAT2, a necessary component of the type I interferon signaling pathway, and targets it for degradation. We now demonstrate that the ability of dengue NS5 to associate with and degrade STAT2 is species specific. Thus, NS5 is able to bind and degrade human STAT2, but not mouse STAT2. This difference was exploited to demonstrate, absent manipulation of the viral genome, that NS5-mediated IFN antagonism is essential for efficient virus replication. Moreover, we demonstrate that differences in NS5 mediated binding and degradation between human and mouse STAT2 maps to a region within the STAT2 coiled-coil domain. By using STAT2(-/-) mice, we also demonstrate that mouse STAT2 restricts early dengue virus replication in vivo. These results suggest that overcoming this restriction through transgenic mouse technology may help in the development of a long-sought immune-competent mouse model of dengue virus infection.

Dengue

INTRODUCTION

Dengue is a vector-borne viral infection that endangers an estimated 2.5 billion people. Disease caused by dengue ranges from a relatively minor febrile illness to a life-threatening condition characterized by extensive capillary leak. A greater understanding of dengue has the potential to improve both the clinical management of individual cases and the control of the disease.

SOURCES OF DATA

We searched the available literature using PubMed, Embase and Web of Science for relevant articles and abstracts.

AREAS OF AGREEMENT

Addressing our gaps in the understanding of disease pathogenesis and improving our knowledge of dengue virus biology are necessary in order to develop tools to effectively control, diagnose and treat the disease.

AREAS OF CONTROVERSY

The pathogenesis of dengue is multifactorial and depends on both host and virus factors. A more integrated understanding of disease pathogenesis is necessary.

AREAS TIMELY FOR DEVELOPING RESEARCH

There are many questions related to disease pathogenesis, development of diagnostics, drug and vaccine development and individual case management that need addressing if the disease is to be successfully tackled.

Altered fluid, electrolyte and mineral status in tropical disease, with an emphasis on malaria and leptospirosis

Fluid, electrolyte and mineral perturbations are prevalent features of tropical disease. Hemodynamic alterations, fever, nitrogen wasting, and changes in membrane transport and acid-base balance contribute to these perturbations. Models of malaria and leptospirosis have been used to show that common hemodynamic changes in tropical disease include decreased systemic vascular resistance, increased cardiac output and increased renal vascular resistance. Blood volume is initially increased, but it decreases as disease progresses. Response to fluid loading is decreased. Diabetes insipidus is occasionally observed in malaria. Hyponatremia occurs frequently in tropical diseases, as a result of increased levels of antidiuretic hormone (vasopressin), entry of sodium into cells, sodium loss and resetting of osmoreceptors. Natriuresis and kaliuresis are observed in patients with leptospirosis. Large amounts of sodium and potassium are lost in stool as a result of diarrhea. Hypernatremia is uncommon, whereas hypokalemia caused by hyperventilation is often observed (more frequently in patients with leptospirosis and kaliuresis). During severe tropical infective episodes, hyperkalemia results from intravascular hemolysis or rhabdomyolysis, and occasionally from decreased activity of Na+,K+-ATPase. Hypocalcemia, hypomagnesemia and hypophosphatemia are common features of both malaria and leptospirosis. Loss of magnesium in the urine is uniquely associated with leptospiral nephropathy. Hypozincemia and hypocupremia can also develop during tropical infection, and might interfere with a patient's immune response. These electrolyte and mineral perturbations are transient and quickly resolve when the disease is controlled.

Dengue virus regulates the expression of hemostasis-related molecules in human vein endothelial cells

OBJECTIVES

Hemorrhage is considered to be the primary sign of Dengue hemorrhagic fever and Dengue shock syndrome. In the present study we focused on the mechanism in the pro- and anti-coagulation after Dengue virus infection.

METHODS

The effects of Dengue virus on the expression and secretion of tissue factor, tissue factor inhibitor, thrombomodulin, tissue plasminogen activator and plasminogen activator inhibitor type-1 in human umbilical vein endothelial cells were detected in this study.

RESULTS

It was shown that Dengue virus could promote the expression of thrombomodulin in cultured human umbilical vein endothelial cells, thus increasing anticoagulation, and enhancing tissue plasminogen activator activity and therefore increased hemorrhage risk.

CONCLUSIONS

The changes above may play an important role in the development of Dengue hemorrhagic fever and Dengue shock syndrome.

Dengue-3 virus genomic differences that correlate with in vitro phenotype on a human cell line but not with disease severity

We compared the full genome sequence of nine clinical isolates of dengue virus obtained during an epidemic of dengue-3 in French Polynesia in 1989, from patients with various presentations of disease. The isolates, all belonging to Genotype I, had 25 amino acid substitutions. There was no association with disease severity. When cultured in the K562 human erythroleukemia cell line, the isolates induced a range of cell growth inhibitions that was not associated with the degree of disease severity. By contrast, some substitutions--charge changes in NS1 and NS5, side-chain differences in NS1, loss of the E-153 potential glycosylation site, and 11 nucleotide insertions in the 3'UTR--that have been suggested to result in an increase or attenuation of dengue infection, appeared to be associated with the level of inhibition. These data represent the first documented study of an association between differences in the full dengue-3 genome of clinical isolates and the in vitro phenotype of these isolates on a human cell line.

Aggressive management of dengue shock syndrome may decrease mortality rate: a suggested protocol

OBJECTIVES

Dengue shock syndrome is a leading cause of mortality among Indian children. In January 2000, we instituted a protocol for aggressive management of children with dengue shock syndrome. The objective of this study was to compare outcomes (duration of ventilation, pediatric intensive care unit stay, incidence of acute respiratory distress syndrome, and intensive care unit and hospital mortality) before and after the protocol.

DESIGN

Retrospective chart review.

SETTING

Pediatric intensive care unit at a tertiary teaching hospital.

PATIENTS

One hundred and fourteen patients admitted between July 1997 and December 1999 received standard therapy recommended by the World Health Organization (WHO) and were designated as the WHO guidelines group (W), whereas 96 patients admitted between January 2000 and December 2001 were treated by our protocol and designated as the protocol group (P).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The patients in each group were equally matched in terms of age, Pediatric Risk of Mortality, and number with dengue hemorrhage fever grade IV, although the platelet counts were higher in the W group compared with the P group (geometric mean 42.2, confidence interval 36.9, 48.4 vs. geometric mean 36.7, confidence interval 33.3, 40.5, p < .05). Patients in the W group received less fluids in the first hour compared with the P group (median and interquartile range 20 mL/kg, 15 and 20 vs. 30 mL/kg, 20 and 60). Fluid was actively removed less often in the W group than the P group (6 of 111 vs. 45 of 96, p < .05). There was no difference in the need for ventilation or incidence of acute respiratory distress syndrome between groups, although among dengue hemorrhage fever grade IV patients, the number requiring ventilation (17 of 30 vs. 20 of 23, p < .05) and the incidence of acute respiratory distress syndrome (9 of 30 vs. 17 of 23, p < .05) were significantly greater in the W group compared with the P group. The duration of ventilation (1.5 +/- 1.7 vs. 4.2 +/- 2.9 days, p < .05) and length of intensive care unit stay (3.0 +/- 2.8 vs. 3.4 +/- 2.9 days, p < .05) were significantly less in the W group. The pediatric intensive care unit mortality (16.6% vs. 6.3%, p < .05) was significantly higher in the W group than in the P group.

CONCLUSIONS

Patients with dengue shock syndrome are at high risk of mortality due to refractory shock and multiple organ failure. Survival was better for patients in the P group. Aggressive shock management and possibly the use of judicious fluid removal may decrease mortality rates in the severest forms of dengue shock syndrome.

Dengue viral infections

Dengue viral infections are one of the most important mosquito borne diseases in the world. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever (DHF), or dengue shock syndrome. Annually, 100 million cases of dengue fever and half a million cases of DHF occur worldwide. Ninety percent of DHF subjects are children less than 15 years of age. At present, dengue is endemic in 112 countries in the world. No vaccine is available for preventing this disease. Early recognition and prompt initiation of appropriate treatment are vital if disease related morbidity and mortality are to be limited. This review outlines aspects of the epidemiology of dengue infections, the dengue virus and its mosquito vector, clinical features and pathogenesis of dengue infections, and the management and control of these infections.

Predictors of spontaneous bleeding in Dengue

OBJECTIVE

To identify the predictive factors for spontaneous bleeding manifestations in Dengue illness in infants and children.

METHODS

60 cases of Dengue viral infection with spontaneous skin and or mucosal bleed were compared with 72 cases without spontaneous bleed. The protean bleeding manifestations in dengue infection were recorded. Various clinical and laboratory parameters were analyzed using univariate and logistic regression analysis.

RESULTS AND CONCLUSION

Prothombin time was abnormal only in cases with spontancous bleed. A combination of (a) biphasic pattern of fever, (b) hemoconcentration, (c) platelet count less than 50,000/mm3 and (d) elevated ALT had a sensitivity of 79.2%, specificity of 64.7% with a positive predictive value of 70% and a negative predictive value of 75% in predicting spontaneous bleeding in dengue.

Anti-TNF antibody treatment reduces mortality in experimental dengue virus infection

Here we describe a lethal mouse model infected with dengue virus type 2 with several similarities to human DEN-2 infection. Clinically animals demonstrated anemia, thrombocytopenia, pre-terminal paralysis and shock. The most impressive changes were seen with tumor necrosis factor (TNF)-alpha, which abruptly and steeply increased 24 h before the exitus (mean at day 6). Serum levels of IL-1beta, IL-6, IL-10, IL-1 receptor antagonist and soluble TNF receptor I continuously increased during the time of infection. A 100% mortality rate was noted in that group of animals. Treating animals with anti-TNF-alpha serum reduced mortality rate down to 40% (P<0.05). Our model supports the view that activation of innate immune response is at least partially responsible for mortality in DEN-2 infection, and in line with this concept, anti-TNF treatment significantly reduces mortality rates.