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PubMedDate not supplied

[Apoptotic cell death in response to dengue virus infection: what are the consequences of viral pathogenesis?].

Dengue is a human disease of viral etiology which may be fatal in its hemorragic form. It is widely spread in the tropical areas of the different continents and has been dramatically expanding over the past 30 years. Although an immunological disorder is thought to be involved in dengue physiological symptoms, the pathogenesis of dengue hemorragic fever has not yet been elucidated. Whether the immune response is deleterious or beneficial to the host remains a matter of debate. Other factors, related to virus replication in specific host cells, could also contribute to the severity of the disease. Apoptotic cell death is one of the important consequences of dengue virus infection both in vitro and in vivo. Dengue replication triggers apoptotic signals in neurons and hepatocytes although the original effectors and kinetics differ. Implications of the ongoing apoptotic processes in viral pathogenesis will be further discussed.

Animals↗
PubMed1998

Dengue outbreak associated with multiple serotypes--Puerto Rico, 1998.

Dengue is an acute viral disease caused by any of the four dengue virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4). The principal mosquito vector is Aedes aegypti, which has a worldwide distribution in tropical and many subtropical areas. All four virus serotypes produce a similar illness characterized by fever, headache, myalgias, arthralgias, rash, nausea and vomiting and induce life-long immunity that is specific to the infecting serotype. A small proportion of infected persons may develop the severe form of disease, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), but with early diagnosis and proper supportive management, fatality rates may be <1%. This report summarizes an epidemic of dengue in Puerto Rico in 1998 associated with multiple dengue serotypes.

Adolescent↗
PubMed1998

[Mucocutaneous manifestations of dengue].

CHANGING EPIDEMIOLOGY: During the last half of the 20th century, dengue has spread to most countries in the inter-tropical zone and today is the most common cause of human arbovirus infection. In tropical zones, dengue is a frequent cause of fever and can be observed in travellers returning from an endemic zone. SKIN AND MUCOSAL MANIFESTATIONS: Though variable, skin and mucosal manifestations are important to recognize. Exanthema occurs late after constitutional symptoms and is suggestive. Minimal hemorrhagic lesions involving the skin and mucosa are observed in common dengue. They usually do not signal progression to authentic hemorrhagic dengue or shock. DIAGNOSIS: Skin manifestations of dengue raise the more general problem of diagnosis in travellers returning from tropical zones who develop fever and rash.

Dengue↗
PubMed1998

Nucleotide sequence and deduced amino acid sequence of the nonstructural proteins of dengue type 3 virus, Bangkok genotype.

The nucleotide sequence of the nonstructural protein gene (1,610 bases) of dengue 3 virus (Bangkok genotype; CH53489 isolated in 1973) has been determined in both forward and reverse directions. The PCR based cycle sequencing technic by the enzymatic method of Sanger et al using a sequencing primer 5'-end labeled with gamma-32P-ATP was the method of our choice for sequence analysis. Two cDNA templates were prepared by RT-PCR technique starting from the nucleotides 6,306-6,969 and 6,925-7,915 of the dengue 3 genome with the lengths of 663 and 990 base pairs respectively. In our cycle sequencing experiments, it has been observed that the substitution of 7-deaza-dG for dG in DNA eliminated most of the secondary structures that produce gel artifacts. The final sequence results of these two cDNA templates were established from their sequence data determined on both strands in opposite directions. Alignment between the newly established nucleotide sequences as well as their deduced amino acid sequences of the Bangkok dengue 3 (CH53489) virus and the published sequence data of the dengue 3 prototype (H87) was manipulated by the PC-DOS-GIBIO DNASIS TM 06-00 software. The homology of the nucleotide sequences between the two dengue 3 viruses was 96.65%. The deduced amino acid sequence from nucleotides 6,306-7,915 of the two viruses showed conserved amino acids of the nonstructural protein NS4a and 6 amino acid changes in NS4b and NS5.

Amino Acid Sequence↗
PubMed1998

Tumor necrosis factor alpha levels in plasma and whole-blood culture in dengue-infected patients: relationship between virus detection and pre-existing specific antibodies.

The pathogenesis of dengue hemorrhagic fever (DHF) is not well known, but the role of host factors has been suggested. The level of immunoreactive circulating and cell-generated tumor necrosis factor alpha (TNF alpha) was studied in 35 patients with DHF; its relationship with virus isolation and/or genome detection by reverse transcription polymerase chain reaction (RT-PCR) and specific antibodies were detected by hemagglutination inhibition (HI). Large variation of TNF alpha plasma levels was obtained in dengue-infected patients at the same stage of the disease and at the same day after infection. Most of the patients (14 out of 17 patients) who displayed augmented spontaneous in vitro production of TNF alpha by heparinized whole-blood culture compared with controls also had elevated levels of TNF alpha in the plasma. The TNF alpha values in lipopolysaccharide and phytohemagglutinin heparinized whole-blood cultures were not higher in patients than in controls, but low TNF alpha levels were obtained in three out of 30 patients. An inverse correlation was observed between spontaneous in vitro TNF alpha production and viral replication, which raises the issue of the antiviral effect of TNF alpha in dengue infection. The results do not support the hypothesis of the role of antibody-dependent enhancement giving rise to increased viremic titers and production of TNF alpha in patients. The present study demonstrates the activation of the TNF alpha-producing cells in dengue-infected patients and suggests further investigation to define the mechanism and the role of TNF alpha in the pathogenesis of dengue virus infection.

Adolescent↗
PubMed2004

Differential display RT-PCR analysis of ECV304 endothelial-like cells infected with dengue virus type 2 reveals messenger RNA expression profiles of multiple human genes involved in known and novel roles.

Differential display (DD)-RT-PCR was employed to analyze mRNAs from ECV304 human endothelial-like cells undergoing apoptosis following infection with the virulent New Guinea C strain of dengue virus type 2 in order to elucidate the cellular gene responses to dengue viral infection at the transcriptional level. We isolated, sequenced, and identified 203 differentially expressed and overlapping cDNA fragments, all of which were of human origin except 1 that was of viral origin. Out of these, 78 were individual distinct clones comprising 46 and 32 expressed sequence tags (ESTs) that exhibited upregulated and downregulated trends, respectively. Of the 78 differentially expressed mRNAs, 16 did not match any characterized genes or ESTs. The remaining 62 mRNAs modified by dengue virus infection matched known genes, including those encoding components of the cell cycle (Anillin, CDC27), cytoskeleton (epsilon-tubulin), signal transduction (OPHN1, PPP2R2A, TIRAP), protein translation and modification (EIF3S10, IF2, TMEM1), transcriptional regulation (alpha-NAC, C20orf104, EGR1, ELP2), apoptotic cell death (RICK), membrane (BPAG1), and mitochondrial-related proteins. Semiquantitative RT-PCR and real-time RT-PCR authenticated further the altered expression patterns of selected genes of interest. These data demonstrate the feasibility of mRNA DD in providing insights into the complex responses of the transcriptional machinery of permissive and apoptotic human endothelial-like cells in the pathogenesis of dengue and/or its complications induced by the virulent dengue virus type 2.

Apoptosis↗
PubMed2000

Crystal structure of Dengue virus NS3 protease in complex with a Bowman-Birk inhibitor: implications for flaviviral polyprotein processing and drug design.

Dengue viruses are members of the Flaviviridae and cause dengue fever and the more severe dengue hemorrhagic fever. Although nearly 40 % of the world's population is at risk of dengue infection, there is currently no effective vaccine or chemotherapy for the disease. Processing of the dengue polyprotein into structural and non-structural proteins in a host, which is essential for assembly of infective virions, is carried out by the combined action of host proteases and the trypsin-like, two-component viral NS2B/NS3 serine protease. Although NS2B strongly stimulates the catalytic NS3 protease domain, the latter is fully active against small substrates and possesses detectable activity against larger substrates, making both forms of the enzyme possible targets for drug design. In the crystal structure of a complex of the protease with a Bowman-Birk inhibitor reported here, an Arg residue at the P1 position of the inhibitor is bound in a manner distinctly different from that in other serine proteases of comparable specificity. However, because the regulatory component, NS2B, is not present in the complex, the physiological implications of this observations are currently unclear. The redundant nature of interaction of P1 Arg and Lys residues with Asp129, Tyr150 and Ser163 of the enzyme provides an explanation for the observed behavior of several site-specific mutants of Asp129 in the protease. The strong level of conservation of residues in the protease that interact with the P1 Arg, along with conservation of Arg at P1 of most cleavage sites in other flaviviruses, suggests that observations from this structure are likely to be applicable to many flaviviruses. The structure provides a starting point for design of site-specific mutations to probe the mechanism of catalysis by the catalytic domain, its activation by the regulatory domain and for design of specific inhibitors of enzymatic activity.

Catalytic Domain↗
PubMed1999

Influence of the human high-affinity IgG receptor FcgammaRI (CD64) on residual infectivity of neutralized dengue virus.

We examined dengue virus immune complex-phagocyte interaction with respect to a single Fc receptor class using a transient expression system involving the high-affinity human macrophage receptor, FcgammaRI. We found that New Guinea C strain dengue 2 virus formed well-defined plaques in normal and transfected COS cells and we analyzed the structural determinants of FcgammaRI-mediated binding and internalization of dengue 2 virus immune complexes by expressing native or truncated forms of the receptor in COS cells, alone or with its accessory gamma chain signaling unit, which bears an immunoreceptor tyrosine-based activation motif (ITAM). The residual infectivity of dengue 2 virus treated with neutralizing human antiserum was strikingly higher in FcgammaRI-bearing COS cells than in controls. Compatible with the IgG subclass specificity of FcgammaRI, this difference was abrogated quantitatively by treatment of FcgammaRI-transfected cells with human IgG1 but not IgG2 myeloma protein. The magnitude of receptor-mediated plaque formation after cotransfection with gamma chain was also significantly higher than in controls but was less than that observed with FcgammaRI transfection only, a difference probably explained by reduced levels of FcgammaRI expression in gamma chain cotransfectants. Deletion of the FcgammaRI cytoplasmic domain had no effect on receptor-mediated immune complex infectivity. We conclude that the FcgammaRI extracellular domain is sufficient for internalization of infectious dengue virus immune complexes through a mechanism that does not involve classical ITAM-dependent signaling.

Animals↗
PubMed1979

Electron microscopic observations on Aedes albopictus cells infected with dengue viruses.

In dengue virus infected Aedes albopictus cells, electron-dense particles, larger than single ribosomes, were arranged on the cytoplasmic sides of rough endoplasmic reticulum (RER) membranes. Mature virions 40--45 nm in diameter as well as vesiculotubular structures 50--120 nm in diameter appeared in enlarged cisternae of RER filled with fine granular substance. Many of the mature virions and somewhat degenerated vesiculotubular structures remained to be enclosed in membranous structures presumably derived from RER, even after degeneration of infected cells. The findings suggest that development of dengue viruses in cultured A. albopictus cells takes place in close relationship with the activated membranes of RER. Other morphological changes observed in dengue infected A. albopictus cells were 1. electron-dense "double-track structures" in areas of virion morphogenesis, 2. fine crystalline structures in type-2 dengue infected cells, and 3. aggregates of nucleoid structures, in cells persistently infected with type 2 dengue virus. The implication and nature of these structures in relation to virion morphogenesis remain to be investigated.

Aedes↗
PubMed1994

Restriction enzyme analysis of American region dengue viruses.

Restriction fragment heterogeneity of Hae III digestion products of cDNA to virion RNA was used to map the distribution of dengue virus topotypes found in the American region. By comparing the electrophoretic patterns of fragments produced, dengue virus isolates were placed in groups that agreed with those previously determined by oligonucleotide fingerprinting. Dengue-1 and dengue-4 viruses occur throughout the western hemisphere as single genetic types, with most of the isolates sharing at least 70% of their Hae III restriction enzyme fragments. Dengue-2 virus exists as two topotypes in the region with apparently non-overlapping distributions. The Puerto Rico topotype, which has been in the Caribbean for at least 40 years, is genetically diverse, while the Jamaica topotype, first isolated in 1981, is more homogeneous and has expanded its range from the original Caribbean focus to South America.

Aedes↗
PubMed1996

Dengue in Spanish travelers returning from the tropics.

Dengue is seldom recognized as an imported disease in Europe. A prospective clinical study was carried out in 37 travelers suspected to have dengue infection on their return from dengue-endemic areas. Anti-dengue antibodies were found in 24 of 37 patients (14 recent infections and 10 undetermined). The most common features among the recent infections were fever (100%), thrombocytopenia (61.5%), abnormal liver function tests (61.5%), and rash (53.8%). In one case, denguehemorrhagic fever grade III was confirmed and later followed by depression and suicide of the patient. The possibility of local transmission of dengue in Spain is discussed.

Adult↗
PubMed2001

Management of dengue fever in ICU.

Dengue virus infection can cause a wide spectrum of illness. Thrombocytopenia with concurrent haemoconcentration differentiates dengue haemorrhagic fever from classical dengue fever. Only cases with shock or unstable vitals signs need admission in the pediatric intensive care. The management is essentially supportive and symptomatic. The key to success is frequent monitoring and changing strategies. A rise in hematocrit of 20% along with a continuing drop in platelet count is an important indicator for the onset of shock. Patients in grade I and II should be closely monitored for signs of shock. The management of dengue shock syndrome (grade III and IV) is a medical emergency needing prompt and adequate fluid replacement for the rapid and massive plasma losses through increased capillary permeability. Early and effective replacement of plasma losses with plasma expanders or fluid and electrolyte solutions results in a favourable outcome in most cases. The ideal fluid management should include both cystalloids and colloids (including albumin). Cystalloids are given as boluses as rapidly as possible, and as many as 2 to 3 boluses may be needed in profound shock. Colloidal fluids are indicated in patients with massive plasma leakage and in whom a large volume of cystalloids has been given. Frequent recording of vital signs and determinations of haematocrit are important in evaluating the results of treatment. Apart from correction of electrolyte and metabolic disturbances, oxygen is mandatory in all patients of shock. Some patients develop DIC and need supportive therapy with blood products (blood, FFP and platelet transfusions). Polyserositis, in the form of pleural effusion and ascitis, are common in cases of dengue shock syndrome, and if possible, drainage should be avoided as it can lead to severe hemorrhages and sudden circulatory collapse. The prognosis depends mainly on the early recognition and treatment of shock.

Adolescent↗
PubMed2002

A clinical, serological, and immunological study in a Japanese traveler with dengue fever.

We describe the results of clinical, serological, and immunological studies in a Japanese traveler with dengue fever (DF). DF was confirmed by isolation of dengue virus from the serum, a positive direct reverse-transcription polymerase chain reaction (RT-PCR) test, and a high titer of anti-IgM antibody to dengue virus. Interestingly, in this patient infected by dengue virus serotype 3, we found a low CD4/CD8 ratio and a decrease in CD4 lymphocytes, a variation of cross-reaction to dengue virus serotypes 1, 2, and 4, and high serum interferon-gamma levels just after a transient elevation of interleukin-12.

Adult↗
PubMed2002

Travel-acquired dengue infection: clinical spectrum and diagnostic aspects.

BACKGROUND: Dengue fever is increasingly recognized in travelers returning from endemic areas with acute febrile illness; however, its true burden in nonendemic countries is unknown. Only few studies focus on clinical manifestations and serological findings in primarily nonimmune individuals. PATIENTS AND METHODS: We analyzed the epidemiology, clinical manifestations and virological results in patients with imported acute dengue infection who presented at our travel clinic in Frankfurt am Main, Germany, between September 1998 and November 2000. An immunochromatographic test and an immunofluorescence assay were used for antibody testing. RESULTS: Dengue fever was confirmed in 13 patients, thus being the second commonest tropical infection after malaria in patients with fever and a travel history to a tropical country (18 cases per 1,000 patient visits per year). Most patients had only spent a short time abroad, either in South Central or South East Asia or in the Caribbean. CONCLUSION: The clinical features considered typical for dengue were not always present. Antibody assays were typically negative early in the course of disease, with seroconversion occurring only after cessation of clinical symptoms. A high index of suspicion is needed in these patients who often present without typical features of dengue and whose early antibody tests may be negative.

Acute Disease↗
PubMed1985

Dengue and hepatic failure.

Dengue hemorrhagic fever/dengue shock syndrome is a serious manifestation of dengue fever, which is observed predominantly in the tropical regions of the West Pacific and in Southeast Asia and is associated with secondary infections, mainly in children under age 15. A concomitant microangiopathic coagulopathy has been described; moreover, encephalopathy and even Reye's syndrome have been rarely reported. This report describes a 51-year-old man with secondary dengue infection who presented with clinical evidence of severe hepatitis, encephalopathy, cranial nerve palsy, and microangiopathic coagulopathy and who had a favorable outcome. A careful surveillance for the occurrence of secondary dengue in the Western Hemisphere is proposed, and dengue is suggested as a diagnostic possibility in obscure febrile illnesses presenting as either hepatitis, encephalopathy, or coagulopathy in places in which the mosquito vector, Aedes aegypti, is present.

Cranial Nerve Diseases↗
PubMed1986

Geographic classification of dengue-2 virus strains by antigen signature analysis.

Dengue-2 virus strains from different locations were compared by T1-RNAse-resistant oligonucleotide fingerprinting and antigen signature analysis. The latter technique involved construction of radioimmunoassays using monoclonal antibodies that recognize nine distinct dengue-2 type-specific and flavivirus cross-reactive epitopes over a range of antigen concentrations. A statistical method was used to align unknown dengue antigen concentrations in different strain preparations, allowing comparison of binding profiles. Twenty-six dengue-2 virus strains were separated into five distinct groups (topotypes) on the basis of unique RNA fingerprints. Two of these were represented by New Guinea C, the prototype virus isolated in 1944, and a Philippine strain; others were segregated on the basis of greater than or equal to 80% shared oligonucleotides into similarity groups representing Burma/Thailand (8 strains), Puerto Rico (12 strains), and Jamaica (4 strains). Signature analysis of the prototype and four geographic topotype strains revealed striking antigenic differences. In contrast, a high degree of antigenic similarity was found among strains from the same geographic region. Variation between antigenically distinct strains occurred at both type-specific and group-reactive epitopes, but the widest differences appeared at group-reactive determinants. Signature analysis provides a more rapid and simpler means than RNA fingerprinting of monitoring changes or new introductions of dengue virus populations in a geographic region.

Antibodies, Monoclonal↗
PubMed2004

Private sector hospital response to the 2003 dengue outbreak in the Indian capital metropolis of Delhi.

During 2003, the Indian capital metropolis of Delhi was afflicted with an outbreak of dengue. A private-sector tertiary care hospital responded instantly to the sudden influx of 162 patients during an 8-week interval. That was an unusual challenge because, until 1997, the hospital had exclusively managed patients with ophthalmic disorders. Dengue patients received fiscal concessions and several free services. A multidisciplinary cell was commissioned for case management. Apart from a diagnosis of patients with dengue and their clinical management, suspected or confirmed dengue episodes were instantly reported to health authorities. Anti-mosquito measures in the hospital premises including residential areas for the nursing personnel prevented any local virus transmission. The integrated therapeutic and public health response was associated with a 1.23% case fatality rate. The protocol developed during the dengue outbreak would address every locally reportable disease in the future.

Adolescent↗
PubMed2005

Piezoelectric immunochip for the detection of dengue fever in viremia phase.

The global prevalence of dengue fever has grown so dramatically in recent years that it is endemic in more than 100 countries and has become a major international public health concern. Moreover, since the flu-like symptoms that accompany dengue fever are atypical and varied, the detection procedures currently used to identify it are cumbersome and time-consuming, making early stage epidemiological control and effective medical treatment of this epidemic almost impossible. In this study, a QCM-based detection system was developed in which two monoclonal antibodies against dengue E and NS-1 protein, respectively, were control orientated immobilized on QCM via protein A to produce an immunochip. Various sample pretreatment procedures were evaluated to ascertain the most suitable combination, and both the simulating samples and the clinical specimen were examined by the immunochip. The results revealed that the cibacron blue 3GA gel-heat denature (CB-HD) method was the most effective sample pretreatment technique. Due to the complex composition of the serum, the immunochip could only effectively quantify dengue viral antigens in a 1/1000 untreated simulated sample. With the help of the CB-HD method, the dilution folds were found to capable of being reduced from 1000 to 100, and the detection limit lowered to 1.727 microg/ml (E protein) and 0.740 microg/ml (NS-1 protein) in the original sample. While the cocktail immunochip could not quantify both antigens separately, the higher signal level rendered it a more effective qualification tool for suspect screening. Moreover, the results of the analysis of clinical specimens also proved the ability and future potential of cocktail immunochip in discriminating dengue-positive cases from negative serum specimens in the viremia phase.

Adolescent↗