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quantifying the spatial dimension of dengue virus epidemic spread within a tropical urban environment.dengue infection spread in naive populations occurs in an explosive and widespread fashion primarily due to the absence of population herd immunity, the population dynamics and dispersal of ae. aegypti, and the movement of individuals within the urban space. knowledge on the relative contribution of such factors to the spatial dimension of dengue virus spread has been limited. in the present study we analyzed the spatio-temporal pattern of a large dengue virus-2 (denv-2) outbreak that affected t ...201021200419
west nile virus rna not detected in urine of 40 people tested 6 years after acute west nile virus disease.west nile virus (wnv) causes an acute infection that is usually cleared by an effective immune response after several days of viremia. however, a recent study detected wnv rna in the urine of 5 of 25 persons (20%) tested several years after their initial acute wnv disease. we evaluated an established cohort of 40 persons >6 years after initial infection with wnv. urine collected from all participants tested negative for wnv rna by reverse-transcription polymerase chain reaction and transcription ...201021208926
in vitro antiviral activity of neem (azardirachta indica l.) bark extract against herpes simplex virus type-1 infection.herpes simplex virus type 1 (hsv-1) causes significant health problems from periodical skin and corneal lesions to encephalitis. we report here that an aqueous extract preparation from the barks of neem plant azardirachta indica acts as a potent entry inhibitor against hsv-1 infection into natural target cells. the neem bark extract (nbe) significantly blocked hsv-1 entry into cells at concentrations ranging from 50 to 100 microg/ml. the blocking activity of nbe was observed when the extract was ...201020041417
structure and function analysis of therapeutic monoclonal antibodies against dengue virus type 2.dengue virus (denv) is the most prevalent insect-transmitted viral disease in humans globally, and currently no specific therapy or vaccine is available. protection against denv and other related flaviviruses is associated with the development of antibodies against the viral envelope (e) protein. although prior studies have characterized the neutralizing activity of monoclonal antibodies (mabs) against denv type 2 (denv-2), none have compared simultaneously the inhibitory activity against a gene ...201020592088
sequence-function analysis of the sendai virus l protein domain vi.the large (about 2200 amino acids) l polymerase protein of nonsegmented negative-strand rna viruses (order mononegavirales) has six conserved sequence regions ("domains") postulated to constitute the specific enzymatic activities involved in viral mrna synthesis, 5'-end capping, cap methylation, 3' polyadenylation, and genomic rna replication. previous studies with vesicular stomatitis virus identified amino acid residues within the l protein domain vi required for mrna cap methylation. in our r ...201020609457
tnf-alpha-dependent regulation of cxcr3 expression modulates neuronal survival during west nile virus encephalitis.the chemokine cxcl10 exerts antiviral effects within the central nervous system (cns) through the recruitment of virus-specific t cells. however, elevated levels of cxcl10 may induce neuronal apoptosis given its receptor, cxcr3, is expressed by neurons. using a murine model of west nile virus (wnv) encephalitis, we determined that wnv-infected neurons express tnf-alpha, which down-regulates neuronal cxcr3 expression via signaling through tnfr1. down-regulation of neuronal cxcr3 decreased cxcl10- ...201020579746
a plasmid encoding parts of the dengue virus e and ns1 proteins induces an immune response in a mouse model.a denv-2 plasmid named peii*eiii/ns1*,containing sequences encoding portions of the envelope protein that are potentially involved in the induction of neutralizing antibodies and a portion of the ns1 sequence that is involved in protection, is reported in this work. the synthesized subunit protein was recognized by human sera from infected patients and had the predicted size. the immunogenicity of this construct was evaluated using a mouse model in a prime-boost vaccination approach. the priming ...201020390312
refolded dengue virus type 2 ns1 protein expressed in escherichia coli preserves structural and immunological properties of the native protein.the dengue virus ns1 protein has been shown to be a protective antigen under different experimental conditions but the recombinant protein produced in bacterial expression systems is usually not soluble and loses structural and immunological features of the native viral protein. in the present study, experimental conditions leading to purification and refolding of the recombinant dengue virus type 2 (denv-2) ns1 protein expressed in escherichia coli are described. the refolded recombinant protei ...201020399232
nucleocapsid-like particles of dengue-2 virus enhance the immune response against a recombinant protein of dengue-4 virus.in this study, we evaluate in mice a novel formulation containing nucleocapsid-like particles of dengue-2 virus (recnlp) co-immunized with a chimeric protein composed of the dengue-4 envelope domain iii fused twice within the meningococcal p64k protein of neisseria meningitidis (pd24). the animals receiving the pd24-recnlp mixture showed the highest levels of antiviral antibodies. similar results were obtained for ifnγ secretion levels, indicating a functional th1 cellular response. consistently ...201020640909
two lineages of dengue virus type 2, brazil. 201020202456
selection and identification of b-cell epitope on ns1 protein of dengue virus type 2.ns1 of dengue virus (denv) is an important non-structural protein, which plays an important role in denv replication and dengue infection. in this study, using the phage-displayed peptide library screening method and purified anti-denv2-ns1 polyclonal antibody immunoglobulin g (igg) as target, which was generated from the purified recombinant expressed denv2-ns1 protein immunization on rabbit, seven b-cell epitopes of denv2-ns1 protein were screened. considering the results of comprehensive bioi ...201020211209
structural optimization and de novo design of dengue virus entry inhibitory peptides.viral fusogenic envelope proteins are important targets for the development of inhibitors of viral entry. we report an approach for the computational design of peptide inhibitors of the dengue 2 virus (denv-2) envelope (e) protein using high-resolution structural data from a pre-entry dimeric form of the protein. by using predictive strategies together with computational optimization of binding "pseudoenergies", we were able to design multiple peptide sequences that showed low micromolar viral e ...201020582308
designing cyclic peptide inhibitor of dengue virus ns3-ns2b protease by using molecular docking approach.peptides are preferred for designing inhibitors because of their high activity and specificity. seven cyclopentapeptide inhibitors were designed in this study against dengue virus type 2 (den-2) ns3-ns2b protease: ckrrc, cgrrc, crgrc, crtrc, ctrrc, ckrkc and crrkc. docking analysis was performed to study the enzyme-inhibitor binding interactions. the free energy binding and estimated ki values for all the inhibitors were found to be small (within micromolar range), indicating that the inhibitors ...201021364826
the envelope glycoprotein domain iii of dengue virus type 2 induced the expression of anticoagulant molecules in endothelial cells.dengue virus (dv) causes a non-specific febrile illness known as dengue fever (df), and a severe life-threatening illness, dengue hemorrhagic fever/dengue shock syndrome (dhf/dss). hemostatic changes induced by this virus involve three main factors: thrombocytopenia, endothelial cell damage, and significant abnormalities of the coagulation and fibrinolysis systems. the pathogenesis of bleeding in dv infections remains unknown. in this article, we focused on the dv activating endothelial cells an ...201020526654
optimization of conditions for secretion of dengue virus type 2 envelope domain iii using pichia pastoris.we have developed a recombinant clone of the methylotrophic yeast pichia pastoris capable of secreting dengue virus type 2 envelope domain iii (sediii-2). we explored various induction parameters including media composition, temperature, ph, and methanol concentration, to optimize conditions for sediii-2 expression in shake flask culture. induction at 20°c in the presence of 2% (v/v) methanol in a medium buffered to ph 5.8 resulted in highest secretion of sediii-2. this yield could be further en ...201020538539
antiviral actions of flavanoid-derived compounds on dengue virus type-2.dengue viruses, mosquito-borne members of the flaviviridae family, are the causative agents of dengue fever and its associated complications, dengue haemorrhagic fever and dengue shock syndrome. to date, more than 2.5 billion people in over 100 countries are at risk of infection, and approximately 20 million infections were reported annually. there is currently no treatment or vaccine available for dengue infection. this study employed a whole-cell organism model or in vitro methods to study the ...201020567498
natural attenuation of dengue virus type-2 after a series of island outbreaks: a retrospective phylogenetic study of events in the south pacific three decades ago.dengue is an expanding arboviral disease of variable severity characterized by the emergence of virus strains with greater fitness, epidemic potential and possibly virulence. to investigate the role of dengue virus (denv) strain variation on epidemic activity we studied denv-2 viruses from a series of south pacific islands experiencing outbreaks of varying intensity and clinical severity. initially appearing in 1971 in tahiti and fiji, the virus was responsible for subsequent epidemics in americ ...201020663532
a balb/c mouse model shows that liver involvement in dengue disease is immune-mediated.in the present study, balb/c mice were used to develop a model for the hepatic injury associated to dengue infection. histological analysis after subcutaneous inoculation with a low viral dose of dengue-2 virus showed kupffer cell hyperplasia and an increased inflammatory cellular infiltrate next to the bile ducts on days 5, 7 and 14 post-inoculation, mainly characterized by the presence of mononuclear cells. the liver mrna transcription level of il-1β was highest on the 5th day post-infection ( ...201020673760
morphological changes in vero cells postinfection with dengue virus type-2.although no specific antiviral tablets or injections that can kill the dengue virus are currently available, adequate care and treatment could control its morbidity. interaction of dengue virus to target cells could be an important feature for virus propagation. ultrastructural analysis of this interaction was studied with vero cells. vero cells were treated with dengue virus type-2 at different time intervals at multiplicity of infection (m.o.i) < 10, m.o.i > 10, and m.o.i = 100. it was found t ...201020687131
virucidal activity and chemical composition of essential oils from aromatic plants of central west argentina.the essential oils of seven aromatic plants from central west argentina were isolated by steam distillation and analyzed by a gas chromatography/mass spectrometry technique. the oils were screened for cytotoxicity and in vitro inhibitory activity against herpes simplex virus type 1 (hsv-1), dengue virus type 2 (denv-2) and junin virus (junv). the oils showed a variable virucidal action according to the virus. junv was the least susceptible virus in comparison with hsv-1 and denv-2. the better re ...201020839642
design, synthesis, and in vitro evaluation of potential west nile virus protease inhibitors based on the 1-oxo-1,2,3,4-tetrahydroisoquinoline and 1-oxo-1,2-dihydroisoquinoline scaffolds.the 1-oxo-1, 2, 3, 4-tetrahydroisoquinoline and 1-oxo-1, 2-dihydroisoquinoline scaffolds were utilized in the design and solution phase synthesis of focused libraries of compounds for screening against west nile virus (wnv) protease. exploratory studies have led to the identification of a wnv protease inhibitor (a 1-oxo-1, 2-dihydroisoquinoline-based derivative, 12j) which could potentially serve as a launching pad for a hit-to-lead optimization campaign. the identified hit was devoid of any inh ...201020882963
potential of complementary and alternative medicine in preventive management of novel h1n1 flu (swine flu) pandemic: thwarting potential disasters in the bud.the emergence of novel h1n1 has posed a situation that warrants urgent global attention. though antiviral drugs are available in mainstream medicine for treating symptoms of swine flu, currently there is no preventive medicine available. even when available, they would be in short supply and ineffective in a pandemic situation, for treating the masses worldwide. besides the development of drug resistance, emergence of mutant strains of the virus, emergence of a more virulent strain, prohibitive ...201020976081
upregulation of a novel eukaryotic translation initiation factor 5a (eif5a) in dengue 2 virus-infected mosquito cells.dengue virus, a mosquito-borne flavivirus, is the etiological agent of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. it generally induces apoptosis in mammalian cells, but frequently results in persistent infection in mosquito cells. that mechanism remains to be explored. in turn, a genomic survey through subtractive hybridization (pcr-select cdna subtraction) was conducted in order to find gene(s) that may play a role in interactions between the virus and its host cells.201020819232
the dengue virus envelope protein induced pai-1 gene expression via mek/erk pathways.dengue virus (dv) infections cause mild dengue fever or severe life-threatening dengue haemorrhagic fever (dhf)/ dengue shock syndrome (dss). dv-infected patients have high plasma concentrations of plasminogen activator inhibitor type i (pai-1). however, the mechanism to cause haemorrhage in dv infections remains poorly understood. in this study, investigation was carried out on the purified recombinant domain iii of the envelope glycoprotein of dv serotypes 2 (eiii) and the signalling pathways ...201020886187
a functional abca1 gene variant is associated with low hdl-cholesterol levels and shows evidence of positive selection in native americans.it has been suggested that the higher susceptibility of hispanics to metabolic disease is related to their native american heritage. a frequent cholesterol transporter abca1 (atp-binding cassette transporter a1) gene variant (r230c, rs9282541) apparently exclusive to native american individuals was associated with low high-density lipoprotein cholesterol (hdl-c) levels, obesity and type 2 diabetes in mexican mestizos. we performed a more extensive analysis of this variant in 4405 native american ...201020418488
comparison of reverse transcription loop-mediated isothermal amplification, conventional pcr and real-time pcr assays for japanese encephalitis virus.we developed and evaluated a reverse transcription loop-mediated isothermal amplification (rt-lamp) assay for detecting japanese encephalitis virus (jev). the sensitivity of the jev rt-lamp assay was in concordance with that of real-time rt-pcr and 10-fold more sensitive than that of conventional rt-pcr, which the detection limit was 24 copies/μl. the jev rt-lamp was highly specific, which no cross-reactivity was found with dengue-2 virus, rabies virus, norovirus, astrovirus and human enteroviru ...201021116858
tumour necrosis factor alpha (tnf-alpha) stimulation of cells with established dengue virus type 2 infection induces cell death that is accompanied by a reduced ability of tnf-alpha to activate nuclear factor kappab and reduced sphingosine kinase-1 activity.tumor necrosis factor alpha (tnf-α) has an antiviral role in some infections but in dengue virus (denv) infection it is linked to severe pathology. we have previously shown that tnf-α stimulation cannot activate nuclear factor κb (nf-κb) to the fullest extent in denv-2-infected cells. here, we investigate further responses of denv-2-infected cells to tnf-α, focussing particularly on cell death and pro-survival signals. tnf-α stimulation of productively denv-2-infected monocyte-derived macrophage ...201021148274
dengue virus rna purification from human plasma: a comparison of two techniques.dengue virus rna purification from human plasma is useful for research and clinical purposes. dengue is endemic in the espirito santo state, brazil, and it is progressively becoming a hard-to-control public health problem [1]. dengue virus types 1, 2 and 3 are currently found in brazilian territory, and recently dengue virus type 4 has been reported to enter brazilian borders. this virus spreads rapidly during epidemic outbreaks, and thousands of patients are infected annually, with an underesti ...201021161397
acute dengue virus 2 infection in gabonese patients is associated with an early innate immune response, including strong interferon alpha production.dengue is now a leading cause of morbidity and mortality throughout the tropics. we conducted the first ex vivo study of dengue fever (df) in african patients infected during the first gabonese dengue virus 2 (denv-2) outbreak in 2007, in order to investigate cytokine production, including the antiviral cytokine ifn-α, reported to be a potent inhibitor of denv replication in vitro.201021167041
the human immune response to dengue virus is dominated by highly cross-reactive antibodies endowed with neutralizing and enhancing activity.antibodies protect against homologous dengue virus (denv) infection but can precipitate severe dengue by promoting heterotypic virus entry via fcγ receptors (fcγr). we immortalized memory b cells from individuals after primary or secondary infection and analyzed anti-denv monoclonal antibodies (mabs) thus generated. mabs to envelope (e) protein domain iii (diii) were either serotype specific or cross-reactive and potently neutralized denv infection. di/dii- or viral membrane protein prm-reactive ...201020833378
vipr: a probabilistic algorithm for analysis of microbial detection microarrays.all infectious disease oriented clinical diagnostic assays in use today focus on detecting the presence of a single, well defined target agent or a set of agents. in recent years, microarray-based diagnostics have been developed that greatly facilitate the highly parallel detection of multiple microbes that may be present in a given clinical specimen. while several algorithms have been described for interpretation of diagnostic microarrays, none of the existing approaches is capable of incorpora ...201020646301
autophagy in viral replication and pathogenesis.autophagy is a catabolic process that is important for the removal of damaged organelles and long-lived proteins for the maintenance of cellular homeostasis. it can also serve as innate immunity to remove intracellular microbial pathogens. a growing list of viruses has been shown to affect this cellular pathway. some viruses suppress this pathway for their survival, while others enhance or exploit this pathway to benefit their replication. the effect of viruses on autophagy may also sensitize ce ...201020077024
silent circulation of arboviruses in cameroon.to investigate the silent circulation and transmission of arthropod-borne viruses (arboviruses) in the fako division of cameroon.201023057269
antiviral activity of four types of bioflavonoid against dengue virus type-2.abstract: background: dengue is a major mosquito-borne disease currently with no effective antiviral or vaccine available. effort to find antivirals for it has focused on bioflavonoids, a plant-derived polyphenolic compounds with many potential health benefits. in the present study, antiviral activity of four types of bioflavonoid against dengue virus type -2 (denv-2) in vero cell was evaluated. anti-dengue activity of these compounds was determined at different stages of denv-2 infection and ...201122201648
expression, purification, and initial structural characterization of nonstructural protein 2b, an integral membrane protein of dengue-2 virus, in detergent micelles.dengue virus causes serious diseases affecting people in tropical and sub-tropical regions. the nonstructural (ns) protein 2b is an integral membrane protein and important for the regulation of viral protease ns3, which is significant for virus replication. the ns2b-ns3 complex is an important drug target for treating dengue fever. however, little is known about the structure of ns2b in its entirety. herein, we describe the expression and purification of this integral membrane protein from cell ...201121875670
systems-biology approaches to discover anti-viral effectors of the human innate immune response.virus infections elicit an immediate innate response involving antiviral factors. the activities of some of these factors are, in turn, blocked by viral countermeasures. the ensuing battle between the host and the viruses is crucial for determining whether the virus establishes a foothold and/or induces adaptive immune responses. a comprehensive systems-level understanding of the repertoire of anti-viral effectors in the context of these immediate virus-host responses would provide significant a ...201121994773
ifn-γ production depends on il-12 and il-18 combined action and mediates host resistance to dengue virus infection in a nitric oxide-dependent manner.dengue is a mosquito-borne disease caused by one of four serotypes of dengue virus (denv-1-4). severe dengue infection in humans is characterized by thrombocytopenia, increased vascular permeability, hemorrhage and shock. however, there is little information about host response to denv infection. here, mechanisms accounting for ifn-γ production and effector function during dengue disease were investigated in a murine model of denv-2 infection. ifn-γ expression was greatly increased after infecti ...201122206036
b-cell responses during primary and secondary dengue virus infections in humans.low-avidity serotype-cross-reactive antibodies are hypothesized to play a key role in triggering severe disease in patients with secondary dengue virus (denv) infection. however, there is little systematic information about the frequency, avidity, and cross-reactivity of denv-specific b cells in individuals experiencing primary instead of secondary infection. we compared denv-specific b-cell responses in a cohort of thai children with primary or secondary denv infection. b cells specific for den ...201121930609
analysis of the complete genome of tembusu virus, a flavivirus isolated from ducks in china.during investigations into the outbreak of duck viral infection in 2010 in china, with a severe drop in egg production, a flavivirus was isolated from the affected ducks. it was characterized as a tembusu virus (tmuv). in this study, we obtained a complete genome sequence of tembusu virus using rt-pcr and race techniques. tmuv genome is a singled-stranded rna, with 10 990 nucleotides in length, and contains a single open reading frame (3410 amino acids) encoding 11 viral proteins with 5'and 3'no ...201122103739
internally quenched fluorescent peptide libraries with randomized sequences designed to detect endopeptidases.identification of synthetic peptide substrates for novel peptidases is an essential step for their study. with this purpose we synthesized fluorescence resonance energy transfer (fret) peptide libraries abz (or mca)-gxxxxxq-eddnp and abz (or mca)-gxxzxxq-eddnp, where x consists of an equimolar mixture of all amino acids, the z position is fixed with one of the proteinogenic amino acids (cysteine was excluded), abz (ortho-aminobenzoic acid) or mca ([7-amino-4-methyl]coumarin) is the fluorescence ...201122067978
clinicohematological profile and platelet trends in children with dengue during 2010 epidemic in north india.objective: to study the clinicohematological profile and the platelet trends in children presenting with dengue infection during the 2010 dengue epidemic in north india and to compare the it with previous epidemics. methods: this retrospective study was carried out in a tertiary care hospital of north india. of the 219 children admitted from august 2010 through november 2010 with suspected dengue infection, 135 w ...201122037856
development of dengue type-2 virus replicons expressing gfp reporter gene in study of viral rna replication.insertion of green fluorescent protein (gfp) encoding-gene into virus genes has provided a valuable tool for flavivirus research. this study aimed to develop dengue virus (denv) replicons expressing gfp reporter that would provide a fast in vitro system to analyze functional roles of specific denv sequences in viral replication. two classes of recombinant replicon constructs were generated; one was a rna-launched replicon with a gfp gene directly inserted into a full-length denv genome (fl-denv/ ...201122197424
the ns1 glycoprotein can generate dramatic antibody-enhanced dengue viral replication in normal out-bred mice resulting in lethal multi-organ disease.antibody-enhanced replication (aer) of dengue type-2 virus (denv-2) strains and production of antibody-enhanced disease (aed) was tested in out-bred mice. polyclonal antibodies (pabs) generated against the nonstructural-1 (ns1) glycoprotein candidate vaccine of the new guinea-c (ng-c) or nsx strains reacted strongly and weakly with these antigens, respectively. these pabs contained the igg2a subclass, which cross-reacted with the virion-associated envelope (e) glycoprotein of the denv-2 nsx stra ...201121731643
Insights into the internalization and retrograde trafficking of dengue 2 virus in BHK-21 cells.Dengue virus (DENV) enters cells via endocytosis, traffics to perinuclear (PN) region, the site of morphogenesis and exits by exocytosis. This study aims to understand the role of dynamin II, endosomes, microtubules (MT) and dynein in the early events of DENV replication.201121991304
Strategies to facilitate the development of uncloned or cloned infectious full-length viral cDNAs: Apple chlorotic leaf spot virus as a case study.Approaches to simplify and streamline the construction of full-length infectious cDNA clones (FL-cDNAs) are needed. Among desirable improvements are the ability to use total nucleic acids (TNA) extracts from infected hosts (to bypass viral purification limitations) for the direct one-step amplification of large FL-cDNAs, the possibility to inoculate plants with uncloned FL-cDNAs and the simplified cloning of these large molecules.201122040379
a thiopurine drug inhibits west nile virus production in cell culture, but not in mice.many viruses within the flavivirus genus cause significant disease in humans; however, effective antivirals against these viruses are not currently available. we have previously shown that a thiopurine drug, 6-methylmercaptopurine riboside (6mmpr), inhibits replication of distantly related viruses within the flaviviridae family in cell culture, including bovine viral diarrhea virus and hepatitis c virus replicon. here we further examined the potential antiviral effect of 6mmpr on several diverse ...201122039536
Analyses of mutations selected by passaging a chimeric flavivirus identify mutations that alter infectivity and reveal an interaction between the structural proteins and the nonstructural glycoprotein NS1.We previously described a single-cycle dengue vaccine (RepliVAX D2) engineered from a capsid (C) gene-deleted West Nile virus (WNV) expressing dengue virus serotype 2 (DENV2) prM/E genes in place of the corresponding WNV genes. That work demonstrated that adaptation of RepliVAX D2 to grow in WNV C-expressing cells resulted in acquisition of non-synonymous mutations in the DENV2 prM/E and WNV NS2A/NS3 genes. Here we demonstrate that the prM/E mutations increase the specific infectivity of chimeri ...201121999990
use of parallel validation high-throughput screens to reduce false positives and identify novel dengue ns2b-ns3 protease inhibitors.dengue virus (denv), a mosquito-borne member of the family flaviviridae, is a significant global pathogen affecting primarily tropical and subtropical regions of the world and placing tremendous burden on the limited medical infrastructure that exists in many of the developing countries located within these regions. recent outbreaks in developed countries, including australia (hanna et al., 2009), france (la ruche et al., 2010), taiwan (kuan et al., 2010), and the usa (cdc, 2010), lead many rese ...201122193283
phylogenetic characterization of dengue virus type 2 in espírito santo, brazil.over the last decade, the espírito santo state, brazil has become an endemic dengue fever location with annual outbreaks of varying magnitude. it is still unclear which geographical route allowed the virus entry in the state and how it has genetically changed since then. therefore we have set out to study the local molecular constitution of the virus and determine phylogenetic similarities and differences with other brazilian locations, as well as locations worldwide. viral envelope genes were p ...201121562769
circulation of different lineages of dengue virus type 2 in central america, their evolutionary time-scale and selection pressure analysis.dengue is caused by any of the four serotypes of dengue virus (denv-1 to 4). each serotype is genetically distant from the others, and each has been subdivided into different genotypes based on phylogenetic analysis. the study of dengue evolution in endemic regions is important since the diagnosis is often made by nucleic acid amplification tests, which depends upon recognition of the viral genome target, and natural occurring mutations can affect the performance of these assays. here we report ...201122076162
maturation of flaviviruses starts from one or more icosahedrally independent nucleation centres.flaviviruses assemble as fusion-incompetent immature particles and subsequently undergo conformational change leading to release of infectious virions. flavivirus infections also produce combined 'mosaic' particles. here, using cryo-electron tomography, we report that mosaic particles of dengue virus type 2 had glycoproteins organized into two regions of mature and immature structure. furthermore, particles of a maturation-deficient mutant had their glycoproteins organized into two regions of im ...201121566648
label-free electrochemical detection of the specific oligonucleotide sequence of dengue virus type 1 on pencil graphite electrodes.a biosensor that relies on the adsorption immobilization of the 18-mer single-stranded nucleic acid related to dengue virus gene 1 on activated pencil graphite was developed. hybridization between the probe and its complementary oligonucleotides (the target) was investigated by monitoring guanine oxidation by differential pulse voltammetry (dpv). the pencil graphite electrode was made of ordinary pencil lead (type 4b). the polished surface of the working electrode was activated by applying a pot ...201122163916
structural mutants of dengue virus 2 transmembrane domains exhibit host-range phenotype.there are over 700 known arboviruses and at least 80 immunologically distinct types that cause disease in humans. arboviruses are transmitted among vertebrates by biting insects, chiefly mosquitoes and ticks. these viruses are widely distributed throughout the world, depending on the presence of appropriate hosts (birds, horses, domestic animals, humans) and vectors. mosquito-borne arboviruses present some of the most important examples of emerging and resurgent diseases of global significance.201121658241
subcellular localizations and time-course expression of dengue envelope and non-structural 1 proteins in human endothelial cells.we performed subcellular fractionation of human endothelial cells (ea.hy926) after a challenge with dengue virus serotype-2 (den-2) at multiplicity of infection (moi) of 10 for 2 h. the cells were fractionated into four fractions including cytosol, membrane/organelle, nucleus and cytoskeleton, and their purity was nicely confirmed by immunofluorescence staining of markers for individual subcellular compartments. western blot analysis of dengue envelope (e) and non-structural 1 (ns1) proteins sho ...201121575706
amino acid changes within the e protein hinge region that affect dengue virus type 2 infectivity and fusion.fifteen mutant dengue viruses were engineered and used to identify aas in the molecular hinge of the envelope protein that are critical to viral infection. substitutions at q52, a54, or e133 reduced infectivity in mammalian cells and altered the ph threshold of fusion. mutations at f193, g266, i270, or g281 affected viral replication in mammalian and mosquito cells, but only i270w had reduced fusion activity. t280y affected the ph threshold for fusion and reduced replication in c6/36 cells. thre ...201121353281
synthetic peptides containing b- and t-cell epitope of dengue virus-2 e domain iii provoked b- and t-cell responses.our previous work applied a combination of bioinformatics approaches and in vitro assays to identify the dengue-2 virus (denv-2)-specific b- and t-cell epitopes. in this report, we first evaluated the antigenicity of both b- and t-cell epitopes reacting with different sera against denv-2 by elisa as well as the ability of t-cell epitope to activate cd4(+) t-cell producing ifn-? using elispot, which showed a specific reactivity between either b- or t-cell epitope and denv-2 antisera, and a signif ...201121419774
Distinct Humoral and Cellular Immunity Induced by Alternating Prime-boost Vaccination Using Plasmid DNA and Live Viral Vector Vaccines Expressing the E Protein of Dengue Virus Type 2.Dengue virus, which belongs to the Flavivirus genus of the Flaviviridae family, causes fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) with infection risk of 2.5 billion people worldwide. However, approved vaccines are still not available. Here, we explored the immune responses induced by alternating prime-boost vaccination using DNA vaccine, adenovirus, and vaccinia virus expressing E protein of dengue virus type 2 (DenV2).201122194710
Establishment of a Stable Cell Line Coexpressing Dengue Virus-2 and Green Fluorescent Protein for Screening of Antiviral Compounds.This study aimed to generate a stable cell line harboring subgenomic dengue virus replicon and a green fluorescent gene (DENV/GFP) for a cell-based model to screen anti-DENV compounds. The gene-encoding envelope protein of DENV-2 was deleted and then replaced with fragments of the GFP gene and a foot-and-mouth-disease virus 2A-derived cleavage site. The human cytomegalovirus immediate early and antisense hepatitis delta virus ribozyme sequences were added at the 5'- and 3'-ends. An internal ribo ...201122068705
espirito santo virus: a new birnavirus that replicates in insect cells.espirito santo virus (esv) is a newly discovered virus recovered as a contamination in a sample of a virulent strain of dengue-2 virus (strain 44/2), which was recovered from a patient in the state of espirito santo, brazil and amplified in insect cells. esv was found to be dependent upon co-infection with a virulent strain of dengue-2 and to replicate in c6/36 insect cells but not in mammalian vero cells. a sequence of the genome has been produced by de novo assembly and was not found to match ...201122171264
n-linked glycosylation of dengue virus ns1 protein modulates secretion, cell-surface expression, hexamer stability, and interactions with human complement.dengue virus (denv) ns1 is a versatile non-structural glycoprotein that is secreted as a hexamer, binds to the cell surface of infected and uninfected cells, and has immune evasive functions. denv ns1 displays two conserved n-linked glycans at n130 and n207. in this study, we examined the role of these two n-linked glycans on ns1 secretion, stability, and function. because some groups have reported reduced yields of infectious denv when n130 and n207 are changed, we analyzed glycosylation-defici ...201121429549
inhibition of bovine viral diarrhea virus rna synthesis by thiosemicarbazone derived from 5,6-dimethoxy-1-indanone.in the present work, we described the activity of the thiosemicarbazone derived from 5,6-dimethoxy-1-indanone (tsc), which we previously characterized as a new compound that inhibits bovine viral diarrhea virus (bvdv) infection. we showed that tsc acts at a point of time that coincides with the onset of viral rna synthesis and that it inhibits the activity of bvdv replication complexes (rcs). moreover, we have selected five bvdv mutants that turned out to be highly resistant to tsc but still sus ...201121430053
letter to the editor: molecular genotyping of dengue virus types 2 and 4 from the guatemalan and honduran epidemics of 2007 using the envelope glycoprotein gene.eight serum specimens collected from dengue patients in guatemala and honduras during the central american epidemic of 2007 were analyzed. virus identification and serotyping performed by a nested rt-pcr assay revealed two denv-1 isolates from guatemala, four denv-2 isolates, two each from guatemala and honduras, and two denv-4 isolates from honduras. viral genotyping determined by phylogenetic analysis of the complete envelope gene sequences demonstrated that the denv-2 isolates from guatemala ...201121234665
virus role during intraepidemic increase in dengue disease severity.dengue epidemics in cuba have repeatedly demonstrated a month-to-month increase in clinical severity during secondary infections. the dengue 2 outbreak that occurred in santiago de cuba in 1997 was accompanied by the most severe intraepidemic increase in disease severity reported to date. it was initially proposed that the appearance of neutralization escape mutants during the course of the epidemic might explain this phenomenon. recent studies have revealed that during the course of this epidem ...201121254883
displacement of the predominant dengue virus from type 2 to type 1 with a subsequent genotype shift from iv to i in surabaya, indonesia 2008-2010.indonesia has annually experienced approximately 100,000 reported cases of dengue fever (df) and dengue hemorrhagic fever (dhf) in recent years. however, epidemiological surveys of dengue viruses (denvs) have been limited in this country. in surabaya, the second largest city, a single report indicated that dengue virus type 2 (denv2) was the predominant circulating virus in 2003-2005. we conducted three surveys in surabaya during: (i) april 2007, (ii) june 2008 to april 2009, and (iii) september ...201122087290
expression and immunoaffinity purification of recombinant dengue virus 2 ns1 protein as a cleavable sumostar fusion.dengue virus (denv) encoded nonstructural one (ns1) is a 352 amino acid protein that exists in multiple oligomeric states and is conserved within the flavivirus family. although ns1 has been heavily researched for its diagnostic utility, there is a gap in the understanding of its role in a range of viral processes, including replication and development of clinical pathologies such as vascular leakage. many of these functions involve unknown interactions with viral and host proteins. this study d ...201122100526
antiviral activity of distictella elongata (vahl) urb. (bignoniaceae), a potentially useful source of anti-dengue drugs from the state of minas gerais, brazil.to investigate the in vitro antiviral activity of distictella elongata (vahl) urb. ethanol extracts from leaves (lee), fruits (fee), stems and their main components.201121895729
dengue virus type 2 recognizes the carbohydrate moiety of neutral glycosphingolipids in mammalian and mosquito cells.dengue viruses infect cells by attaching to a surface receptor which remains unknown. the putative receptor molecules of dengue virus type 2 on the surface of mosquito (ap-61) and mammalian (llc-mk2) cell lines were investigated. the immunochemical detection and structural analysis of carbohydrates demonstrated that the neutral glycosphingolipids, l-3 (glcnacß1-3manß1-4glcß1-1'cer) in ap-61 cells, and nlc(4) cer (galß1-4glcnacß1-3galß1-4glcß1-1'cer) in llc-mk2 cells were recognized by the virus. ...201121265875
highly conserved region 141‒168 of the ns1 protein is a new common epitope region of dengue virus.dengue virus (denv) nonstructural protein 1 (ns1) is a major target of humoral immunity in patients and is believed to be involved in denv pathogenesis. in addition, ns1 is a diagnostic target as it is secreted, and circulates, in patients' plasma at an early stage of viral infection. in this study, we aimed to identify common epitope regions for all serotypes by preparation of mouse monoclonal antibodies (mabs) against ns1. a total of 10 out of the 20 hybridoma clones which were specific to den ...201121519123
differential inhibition of dengue virus infection in mammalian and mosquito cells by iota-carrageenan.the antiviral activity against dengue virus-2 (denv-2) of carrageenans reported here has shown a differential susceptibility of c6/36 ht and vero cells, taken as models of mosquito and mammalian cells, depending on the structural class of polysaccharides: all polysaccharides blocked denv-2 infection in monkey vero cells, but only iota-carrageenans were virus inhibitors in mosquito cells. however, iota-carrageenans were less effective in mosquito cells in comparison with mammalian cells with effe ...201121325483
[circulation of a different lineage of dengue virus serotype 2 american / asian genotype in the peruvian amazon, 2010.]our objective was to determine the genotype of the dengue virus type 2 (denv-2) that circulated in the amazon region of peru between november 2010 and january 2011. we analyzed eight samples collected during dengue surveillance activities in the cities of iquitos, yurimaguas, trujillo, tarapoto and lima between november 2010 and january 2011 that were sent to insitituto nacional de salud. the viruses were isolated in c6/36 ht cell line. viral rna was extracted and the serotype (rt - pcr multiple ...201121537772
binding of flavivirus nonstructural protein ns1 to c4b binding protein modulates complement activation.the complement system plays a pivotal protective role in the innate immune response to many pathogens including flaviviruses. flavivirus nonstructural protein 1 (ns1) is a secreted nonstructural glycoprotein that accumulates in plasma to high levels and is displayed on the surface of infected cells but absent from viral particles. previous work has defined an immune evasion role of flavivirus ns1 in limiting complement activation by forming a complex with c1s and c4 to promote cleavage of c4 to ...201121642539
first report of sylvatic denv-2-associated dengue hemorrhagic fever in west africa.dengue virus (denv) circulates in human and sylvatic cycles. sylvatic strains are both ecologically and evolutionarily distinct from endemic viruses. although sylvatic dengue cycles occur in west african countries and malaysia, only a few cases of mild human disease caused by sylvatic strains and one single case of dengue hemorrhagic fever in malaysia have been reported. here we report a case of dengue hemorrhagic fever (dhf) with thrombocytopenia (13000/-ál), a raised hematocrit (32% above base ...201121829739
vector competence of new zealand mosquitoes for selected arboviruses.new zealand (nz) historically has been free of arboviral activity with the exception of whataroa virus (togaviridae: alphavirus), which is established in bird populations and is transmitted by local mosquitoes. this naive situation is threatened by global warming, invasive mosquitoes, and tourism. to determine the threat of selected medically important arboviruses to nz, vector competence assays were conducted using field collected endemic and introduced mosquito species. four alphaviruses (toga ...201121734146
evaluation of two molecular methods for the detection of yellow fever virus genome.yellow fever virus (yfv), a member of the family flaviviridae, genus flavivirus is endemic to tropical areas of africa and south america and is among the arboviruses that pose a threat to public health. recent outbreaks in brazil, bolivia, and paraguay and the observation that vectors capable of transmitting yfv are presenting in urban areas underscore the urgency of improving surveillance and diagnostic methods. two novel methods (rt-hemi-nested-pcr and sybr(®) green qrt-pcr) for efficient dete ...201121419803
unique heparan sulfate from shrimp heads exhibits a strong inhibitory effect on infections by dengue virus and japanese encephalitis virus.the structure and biological activities of a highly sulfated heparan sulfate (hs) extracted from shrimp (penaeus brasiliensis) heads were characterized. structurally the shrimp hs was more heterogenous than heparin, although it is still highly sulfated. the molecular mass of the shrimp hs preparation was determined to be 32.3kda by gel filtration hplc. analysis by surface plasmon resonance demonstrated that various growth/differentiation factors specifically bound to the shrimp hs with comparabl ...201121806963
[secreted expression of dengue virus type 2 envelope glycoprotein in eukaryotic cells].to secreted express envelope glycoprotein (e) of dengue virus type 2 extracellularly.201121863624
the two component adjuvant ic31® potentiates the protective immunity induced by a dengue 2 recombinant fusion protein in mice.here we evaluated the suitability of the synthetic adjuvant ic31® to potentiate the protective capacity of pd5 protein (domain iii of the envelope protein of dengue 2 virus fused to the carrier protein p64k). unlike alum, pd5 mixed with ic31® induced complete protection against virus challenge in mice and increased ifn-? secretion after in vitro re-stimulation. the induced antibody response was highly specific to the homologous serotype and showed both igg1 and igg2a subtypes. ic31® is a promisi ...201121447316
evolution of attenuating mutations in dengue-2 strain s16803 pdk50 vaccine and comparison of growth kinetics with parent virus.a live-attenuated dengue-2 virus strain s16803 vaccine candidate that is immunogenic and safe in humans was derived by 50 passages in primary dog kidney (pdk) cells. to identify mutations associated with attenuation of the dengue-2 pdk50 vaccine strain, we determined the nucleotide changes that arose during pdk passage of the dengue-2 virus. thirteen mutations distinguished the pdk50 virus from low-passage parent resulting in amino acid substitutions in the premembrane (e89g), envelope (e202k, n ...201121461924
tripeptide inhibitors of dengue and west nile virus ns2b-ns3 protease.a series of tripeptide aldehyde inhibitors were synthesized and their inhibitory effect against dengue virus type 2 (denv2) and west nile virus (wnv) ns3 protease was evaluated side by side with the aim to discover potent flaviviral protease inhibitors and to examine differences in specificity of the two proteases. the synthesized inhibitors feature a varied n-terminal cap group and side chain modifications of a p(2)-lysine residue. in general a much stronger inhibitory effect of the tripeptide ...201121763725
recombination in the nonstructural gene region in type 2 dengue viruses.in view of the rising prevalence of dengue virus and mixing of host and vector populations, complete full-length sequence determination of dengue strains isolated from different epidemic areas is important for the study of virus evolution, pathogenicity, vaccine efficiency and diagnosis. based on the genomic analysis of 51 complete dengue virus sequences, all of which cocirculated in thailand between 1974 and 2001, we report here the occurrence of homologous recombination in the ns5 nonstructura ...201121821995
identification of cis-acting elements in the 3'-untranslated region of the dengue virus type 2 rna that modulate translation and replication.using the massively parallel genetic algorithm for rna folding, we show that the core region of the 3'-untranslated region of the dengue virus (denv) rna can form two dumbbell structures (5' and 3'dbs) of unequal frequencies of occurrence. these structures have the propensity to form two potential pseudoknots between identical five-nucleotide terminal loops 1 and 2 (tl1 and tl2) and their complementary motifs, pk2 and pk1. mutagenesis using a denv2 replicon rna encoding the renilla luciferase re ...201121515677
dengue virus infection of sk hep1 cells: inhibition of in vitro angiogenesis and altered cytomorphology by expressed viral envelope glycoprotein.dengue virus (denv) infection of human endothelial cells has been implicated in the pathobiology of dengue hemorrhagic fever and dengue shock syndrome. however, the mechanisms by which denv infections alter the functional physiology of endothelial cells remain incompletely understood. in the present study, we examined the susceptibility of a human liver sinusoidal endothelial cell line sk hep1 to all four serotypes of denv and studied the effect of the virus on in vitro angiogenesis. all four se ...201121332827
dna vaccines against dengue virus type 2 based on truncate envelope protein or its domain iii.two dna vaccines were constructed encoding the ectodomain (domains i, ii and iii) of the denv2 envelope protein (pe1d2) or only its domain iii (pe2d2), fused to the human tissue plasminogen activator signal peptide (t-pa). the expression and secretion of recombinant proteins was confirmed in vitro in bhk cells transfected with the two plasmids, detected by immunofluorescence or immunoprecipitation of metabolically labeled gene products, using polyclonal and monoclonal antibodies against denv2. b ...201121779317
kinetics of plasma viremia and soluble nonstructural protein 1 concentrations in dengue: differential effects according to serotype and immune status.we describe the magnitude and kinetics of plasma viremia and nonstructural protein 1 (sns1) levels in sequential samples from 167 children with acute dengue, enrolled early in a community study in vietnam. all children recovered fully, and only 5 required hospitalization. among those with dengue virus type 1 (denv-1), plasma viremia was significantly greater in primary (49) than secondary (44) infections and took longer to resolve. in primary denv-2 and 3 infections, viremia was significantly lo ...201121335562
genotype v japanese encephalitis virus is emerging.japanese encephalitis (je) is a global public health issue that has spread widely to more than 20 countries in asia and has extended its geographic range to the south pacific region including australia. je has become the most important cause of viral encephalitis in the world. japanese encephalitis viruses (jev) are divided into five genotypes, based on the nucleotide sequence of the envelope (e) gene. the muar strain, isolated from patient in malaya in 1952, is the sole example of genotype v je ...201121750744
polyclonal antibodies against properly folded dengue virus ns1 protein expressed in e. coli enable sensitive and early dengue diagnosis.the non-structural 1 (ns1) protein plays an important role in dengue diagnosis because it has been detected as a soluble serum antigen in both primary and secondary infections. the ns1 protein was expressed in escherichia coli cells, and the efficiency of four different refolding protocols was tested. all of the protocols generated dimeric ns1 in a conformation similar to that of the protein expressed by eukaryotic cells. a polyclonal antibody produced from the properly folded e. coli recombinan ...201121569796
secreted dengue virus nonstructural protein ns1 is an atypical barrel-shaped high-density lipoprotein.dengue virus (denv) causes the major arboviral disease of the tropics, characterized in its severe forms by signs of hemorrhage and plasma leakage. denv encodes a nonstructural glycoprotein, ns1, that associates with intracellular membranes and the cell surface. ns1 is eventually secreted as a soluble hexamer from denv-infected cells and circulates in the bloodstream of infected patients. extracellular ns1 has been shown to modulate the complement system and to enhance denv infection, yet its st ...201121518917
nf90 binds the dengue virus rna 3' terminus and is a positive regulator of dengue virus replication.viral rna translation and replication are regulated by sequence and structural elements in the 5' and 3' untranslated regions (utr) and by host cell and/or viral proteins that bind them. dengue virus has a single-stranded rna genome with positive polarity, a 5' m7gpppg cap, and a conserved 3'-terminal stem loop (sl) that is linked to proposed functions in viral rna transcription and translation. mechanisms explaining the contributions of host proteins to viral rna translation and replication are ...201121386893
dengue infection increases the locomotor activity of aedes aegypti females.aedes aegypti is the main vector of the virus causing dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the globe. it is known that viruses and other parasites can potentially alter vector behavior. we investigated whether infection with dengue virus modifies the behavior of aedes aegypti females with respect to their activity level.201121408119
evaluation of widely used diagnostic tests to detect west nile virus infections in horses previously infected with st. louis encephalitis virus or dengue virus type 2.primary west nile virus (wnv) infections can be diagnosed using a number of tests that detect infectious particles, nucleic acid, and specific igm and/or igg antibodies. however, serological identification of the infecting agent in secondary or subsequent flavivirus infections is problematic due to the extensive cross-reactivity of flavivirus antibodies. this is particularly difficult in the tropical americas where multiple flaviviruses cocirculate. a study of sequential flavivirus infection in ...201121346058
replication of the primary dog kidney-53 dengue 2 virus vaccine candidate in aedes aegypti is modulated by a mutation in the 5' untranslated region and amino acid substitutions in nonstructural proteins 1 and 3.previous studies have demonstrated reduced replication of the cell culture-adapted dengue-2 virus (denv-2) vaccine candidate, primary dog kidney (pdk)-53, compared with the parental denv-2 strain, 16681, in c6/36 cells. various denv-2 mutants incorporating pdk-53 substitutions singly and in combination into the 16681 genetic backbone were used to identify the genetic basis for impaired replication of the vaccine candidate in vitro in aedes aegypti cell culture (aag2 cells) as well as the reduced ...201121284523
successful propagation of flavivirus infectious cdnas by a novel method to reduce the cryptic bacterial promoter activity of virus genomes.reverse genetics is a powerful tool to study single-stranded rna viruses. despite tremendous efforts having been made to improve the methodology for constructing flavivirus cdnas, the cause of toxicity of flavivirus cdnas in bacteria remains unknown. here we performed mutational analysis studies to identify escherichia coli promoter (ecp) sequences within nucleotides (nt) 1 to 3000 of the dengue virus type 2 (denv2) and japanese encephalitis virus (jev) genomes. eight and four active ecps were d ...201121228244
endurance, refuge, and reemergence of dengue virus type 2, puerto rico, 1986-2007.to study the evolution of dengue virus (denv) serotype 2 in puerto rico, we examined the genetic composition and diversity of 160 denv-2 genomes obtained through 22 consecutive years of sampling. a clade replacement took place in 1994-1997 during a period of high incidence of autochthonous denv-2 and frequent, short-lived reintroductions of foreign denv-2. this unique clade replacement was complete just before denv-3 emerged. by temporally and geographically defining denv-2 lineages, we describe ...201121192856
serratia odorifera a midgut inhabitant of aedes aegypti mosquito enhances its susceptibility to dengue-2 virus.mosquito midgut plays a crucial role in its vector susceptibility and pathogen interaction. identification of the sustainable microflora of the midgut environment can therefore help in evaluating its contribution in mosquito-pathogen interaction and in turn vector competence. to understand the bacterial diversity in the midgut of aedes aegypti mosquitoes, we conducted a screening study of the gut microbes of these mosquitoes which were either collected from fields or reared in the laboratory "cu ...201222848375
effects of ribavirin and hydroxyurea on oral infection of aedes aegypti (l.) with dengue virus.this study was conducted to determine the inhibitory effects of ribavirin and hydroxyurea on dengue virus replication in aedes aegypti mosquitoes. female ae. aegypti mosquitoes were infected with dengue-2 virus and fed ribavirin at a dose of 0.3 mg/ml and/or hydroxyurea at a dose of 6 mg/ml via artificial membrane feeding technique. the virus in infected mosquitoes was isolated using c6/36 cell culture. peroxidase-antiperoxidase (pap) staining was used to detect dengue-infected c6/36 cells and t ...201223413698
Chemical modifications of algal mannans and xylomannans: Effects on antiviral activity.The structures of two sulfated xylomannans extracted from the red alga Nemalion helminthoides were determined. These two fractions plus a sulfated mannan, isolated from the same alga and whose structure was previously reported, were subjected to chemical modification. The mannan was oversulfated with SO(3)-pyridine in dimethyl sulfoxide at 60°C during two and three hours and the xylomannans were subjected to Smith degradation in order to eliminate xylose side-chains. Structural analysis of all d ...201222071136
immunogenicity and protective efficacy of a vaxfectin-adjuvanted tetravalent dengue dna vaccine.a prototype dengue-1 dna vaccine was shown to be safe and immunogenic in a previous phase 1 clinical trial. anti-dengue-1 neutralizing antibody responses were detectable only in the group of volunteers receiving the high dose of nonadjuvanted vaccine and the antibody titers were low. vaxfectin(®), a lipid-based adjuvant, enhances the immunogenicity of dna vaccines. we conducted a nonhuman primate study to evaluate the effect of vaxfectin(®) on the immunogenicity of a tetravalent dengue dna vacci ...201222085548
filovirus research in gabon and equatorial africa: the experience of a research center in the heart of africa.health research programs targeting the population of gabon and equatorial africa at the international center for medical research in franceville (cirmf), gabon, have evolved during the years since its inception in 1979 in accordance with emerging diseases. since the reemergence of ebola virus in central africa, the cirmf "emerging viral disease unit" developed diagnostic tools and epidemiologic strategies and transfers of such technology to support the response of the national public health syst ...201223170174
detection and typing of viruses using broadly sensitive cocktail-pcr and mass spectrometric cataloging: demonstration with dengue virus.virus detection and taxonomic identification of serotypes, strains, or genotypes provide important information relevant for diagnosis, and for the epidemiological characterization and tracking of new strains in an endemic region. in the specific case of dengue virus, rapid serotype identification can also be useful in the treatment of secondary infections that may cause the more severe dengue hemorrhagic fever and dengue shock syndrome. in this work, dengue virus was used as a model to test a ne ...201222579629
[biological properties of virus dengue-3 strains isolated during the epidemic ocurred in havana, 2001-2002].during dengue epidemics in cuba, an increase in clinical severity with the epidemics progression in time, particularly in secondary infections, have been frequently observed. it is considered that this increase could be related with genetic changes in the circulating virus.201223444637
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