TitleAbstractYear(sorted ascending)
west nile virus: the indian scenario.west nile virus (wnv) is an important arthropod borne flavivirus; usually causes a mild infection called west nile fever (wnf) in human and horses. mosquitoes are the principal vectors of wnv. various culex species are found to act as vectors in different geographical regions. the virus is maintained in a bird-mosquito cycle in nature. in india, culex mosquitoes are tentatively incriminated as vectors of wnv. experimental studies have shown that culex tritaeniorhynchus, cx. vishnui, cx. bitaenio ...200314700342
flavivirus isolations from mosquitoes collected from western cape york peninsula, australia, 1999-2000.after the 1st appearance of japanese encephalitis virus (je) on mainland australia in 1998, a study was undertaken to investigate whether je had become established in enzootic transmission cycles on western cape york peninsula. adult mosquitoes were collected during the late wet season from kowanyama and pormpuraaw in april 1999, and pormpuraaw and barr's yard in april 2000. despite processing 269,270 mosquitoes for virus isolation, no isolates of je were obtained. however, other flaviviruses co ...200314710742
serodiagnosis of flaviviral infections and vaccinations in humans. 200314714429
molecular amplification assays for the detection of flaviviruses.over the past 10 years, a number of molecular amplification assays have been developed for the detection of flaviviruses. most of these assays utilize the reverse transcriptase-polymerase chain reaction (rt-pcr) as the amplification format with detection by either agarose gel electrophoresis and ethidium bromide staining or hybridization with molecular probes. recently, a modification of the standard rt-pcr using fluorescent-labeled oligonucleotide probes for detection (taqman) has been describe ...200314714430
tick-borne flaviviruses.tick-borne encephalitis (tbe), one of the most dangerous neuroinfections in europe and asia, is caused by tick-borne encephalitis virus (tbev) and currently involves approximately 11,000 human cases annually, mostly in russia. this chapter describes the main problems associated with the epidemiology, ecology, pathogenesis, and control of this disease. we have attempted to review the factors that influence the incidence and distribution of tbe, and to discuss possible reasons for the different cl ...200314714436
epidemiology of other arthropod-borne flaviviruses infecting humans. 200314714437
formalin-inactivated whole virus and recombinant subunit flavivirus vaccines.the flaviviridae is a family of arthropod-borne, enveloped, rna viruses that contain important human pathogens such as yellow fever (yf), japanese encephalitis (je), tick-borne encephalitis (tbe), west nile (wn), and the dengue (den) viruses. vaccination is the most effective means of disease prevention for these viral infections. a live-attenuated vaccine for yf, and inactivated vaccines for je and tbe have significantly reduced the incidence of disease for these viruses, while licensed vaccine ...200314714438
dna vaccines for flaviviruses. 200314714440
chimeric flaviviruses: novel vaccines against dengue fever, tick-borne encephalitis, and japanese encephalitis.many arthropod-borne flaviviruses are important human pathogens responsible for diverse illnesses, including yf, je, tbe, and dengue. live, attenuated vaccines have afforded the most effective and economical means of prevention and control, as illustrated by yf 17d and je sa14-14-2 vaccines. recent advances in recombinant dna technology have made it possible to explore a novel approach for developing live attenuated flavivirus vaccines against other flaviviruses. full-length cdna clones allow co ...200314714441
prospects for antiviral therapy. 200314714442
vaccination of human volunteers with monovalent and tetravalent live-attenuated dengue vaccine candidates.four serotypes of monovalent live attenuated dengue virus vaccine candidates were tested for reactogenicity and immunogenicity in 49 flavivirus non-immune adult human volunteers. the four monovalent candidates were then combined into a tetravalent formulation and given to another 10 volunteers. neutralizing antibody seroconversion rates after a single-dose monovalent vaccination ranged from 53% to 100%. solicited reactogenicity was scored by each volunteer. a composite index, the reactogenicity ...200314740952
atypical antibody responses in dengue vaccine recipients.eight of 69 (12%) healthy adult volunteers vaccinated with monovalent live-attenuated dengue virus (denv) vaccine candidates had atypical antibody responses, with depressed igm:igg antibody ratios and induction of high-titer hemagglutination-inhibiting and neutralizing (nt) antibodies to all four denv serotypes. these features suggested flavivirus exposure prior to denv vaccination, yet no volunteer had a history of previous flavivirus infection, flavivirus vaccination, or antibody to flavivirus ...200314740953
phase i trial of 16 formulations of a tetravalent live-attenuated dengue vaccine.laboratory-attenuated strains of each of the four dengue serotypes previously tested as monovalent vaccines in volunteers were combined and tested for immunogenicity, safety, and reactogenicity in 16 dosage combinations. tetravalent vaccines made using combinations of high (10(5-6) plaque-forming units [pfu]/dose) or low (10(3.5-4.5) pfu/dose) dosage formulations of each of the four viruses were inoculated in 64 flavivirus non-immune adult volunteers to determine which, if any, formulation raise ...200314740955
ns2a-ns2b sequence analysis of den-4 virus study the genetic variability of den-4 chinese isolates, and to trace the origin of dv4 chinese isolates, we cloned and sequenced the ns2a-ns2b junction of 5 isolates and prototype dv4 (h-241). our results show that isolates from the 1990 guangdong epidemic, which were isolated in the early, middle, and late periods of the epidemic, share the same sequence in the ns2a-ns2b junction. the sequence similarity between isolates from the guangdong epidemic in 1990 and dv4 h-241 is 96%; these isolat ...200315115127
suramin inhibits the in vitro expression of encephalitis b virus proteins ns3 and this study, the mechanism by which suramin inhibits the replication of epidemic encephalitis b virus was explored to provide a theoretical basis for its further application in clinical practice. after viral infection of hepg2 and imr-32 cells, different concentrations of suramin were added to the culture media, and then the cultural supernatants and infected cells were collected 48 h later. for the evaluation of the curative effect, cytopathic effect (cpe), virus titers, the expression of vir ...200315015640
[investigation of arboviruses in lancang river down-stream area in yunnan province].to investigate the epidemic state of arboviruses in the downstream area of lancang river in yunnan province.200315340542
wicking assays for the rapid detection of west nile and st. louis encephalitis viral antigens in mosquitoes (diptera: culicidae).the recent outbreaks of west nile (wn) encephalitis and st. louis encephalitis (sle) in the united states have highlighted the need for rapid and specific methods of detecting arboviral antigens in mosquitoes. we evaluated rapid, field-usable assays for detecting and differentiating wn and sle viruses in mosquito pools, based on a patent-pending, immunochromatographic technology (vectest) formatted on a dipstick. the device provides results in less than 20 min and can be used in laboratories wit ...200312597660
epidemiology of hepatitis c virus infection in australia.since the discovery in 1989 of hepatitis c virus (hcv) as the infectious agent responsible for the vast majority of post-transfusion non-a non-b hepatitis the patterns of transmission and clinical consequences of this highly prevalent flavivirus have been widely studied.200312600649
polystyrene derivatives substituted with arginine interact with babanki (togaviridae) and kedougou (flaviviridae) viruses.outbreaks of new or old diseases appear primarily in tropical zones such as africa, south and central america, or asia. among these diseases, those induced by arboviruses (the best known of which are being yellow fever, dengue, ebola, and sindbis) are under intensive observation by the world health organization. rapid isolation and identification of the viral species is the first step in the diagnosis, study, and control of epidemics. one major problem with the isolation of viruses is capturing ...200312601758
role of type i and type ii interferon responses in recovery from infection with an encephalitic flavivirus.we have investigated the contribution of the interferon (ifn)-alpha/beta system, ifn-gamma and nitric oxide to recovery from infection with murray valley encephalitis virus, using a mouse model for flaviviral encephalitis where a small dose of virus was administered to 6-week-old wild-type and gene knockout animals by the intravenous route. we show that a defect in the ifn-alpha/beta responses results in uncontrolled extraneural virus growth, rapid virus entry into the brain and 100 % mortality. ...200312604807
enzyme-linked immunosorbent assay using recombinant antigens expressed in mammalian cells for serodiagnosis of tick-borne encephalitis.a recombinant plasmid that expresses the tick-borne encephalitis (tbe) virus premembrane (prm) and envelope (e) proteins in mammalian cells was constructed. recombinant proteins retained antigenic and conformational structures similar to those of native virus proteins, and transfected cells released virus-like particles (vlps), which were 1.13-1.14 g/ml in density and 20-30 nm in diameter, into the culture medium. recombinant e proteins were used for the development of an enzyme-linked immunosor ...200312609684
[serological diagnosis of dengue and yellow fever infections in suspected cases from pará state, brazil, 1999].from june to december 1999, 785 serum samples were obtained from patients clinically suspected of having dengue or yellow fever. the patients were referred by public health centers distributed within the six mesoregions of par state, brazil. serum samples were tested for flavivirus antibodies by hemagglutination inhibition test and for dengue and yellow fever viruses by enzyme-linked immunosorbent assay for igm detection. of the sera collected, 563 (71.7%) were positive by hi test and out of th ...200312612738
tick-borne encephalitis.tick-borne encephalitis (tbe) is one of the most dangerous human infections occurring in europe and many parts of asia. the etiological agent tick-borne encephalitis virus (tbev), is a member of the virus genus flavivirus, of the family flaviviridae. tbev is believed to cause at least 11,000 human cases of encephalitis in russia and about 3000 cases in the rest of europe annually. related viruses within the same group, louping ill virus (liv), langat virus (lgtv) and powassan virus (powv), also ...200312615309
enhancing biosynthesis and secretion of premembrane and envelope proteins by the chimeric plasmid of dengue virus type 2 and japanese encephalitis virus.we have constructed a series of plasmids encoding premembrane (prm) and envelope (e) protein genes of dengue virus type 2 (den-2). these plasmids included an authentic den-2 prm-e construct (pcbd2-14-6), and two chimeric constructs, 90% den-2 e-10% japanese encephalitis (je) virus e (pcb9d2-1j-4-3) and 80% den-2 e-20% je e (pcb8d2-2j-2-9-1). monoclonal antibody (mab) reactivity indicated that all three plasmids expressed authentic den-2 virus e protein epitopes representative of flavivirus domai ...200312620809
epitope-blocking enzyme-linked immunosorbent assays for the detection of serum antibodies to west nile virus in multiple avian species.we report the development of epitope-blocking enzyme-linked immunosorbent assays (elisas) for the rapid detection of serum antibodies to west nile virus (wnv) in taxonomically diverse north american avian species. a panel of flavivirus-specific monoclonal antibodies (mabs) was tested in blocking assays with serum samples from wnv-infected chickens and crows. selected mabs were further tested against serum samples from birds that represented 16 species and 10 families. serum samples were collecte ...200312624027
steady-state cleavage kinetics for dengue virus type 2 ns2b-ns3(pro) serine protease with synthetic peptides.the n-terminal part of the ns3 protein from dengue virus contains a trypsin-like serine protease responsible for processing the nonstructural region of the viral polyprotein. enzymatic activity of the ns2b-ns3(pro) precursor incorporating a full-length ns2b cofactor of dengue virus type 2 was examined by using synthetic dodecamer peptide substrates encompassing native cleavage sequences of the ns2a/ns2b, ns2b/ns3, ns3/ns4a and ns4b/ns5 polyprotein junctions. cleavage of the dansylated substrates ...200312625822
diagnosis of tick-borne encephalitis.the actual diagnosis of a tick-borne encephalitis (tbe) must be established in the laboratory because of the non-specific clinical features it presents. the method of choice is the demonstration of specific igm- and igg-serum antibodies by enzyme-linked immuno-sorbent assay (elisa), since these antibodies are detectable in practically every case at the time of hospitalization. early after onset of disease in the cerebrospinal fluid specific antibodies can only be found in 50% of the patients, bu ...200312628812
history of tbe vaccines.tick borne encephalitis was a frequent viral cns disease in europe in the last century, with several hundred hospitalisation cases per year. the causative agent is tick-borne encephalitis virus (tbev), a flavivirus that is transmitted by ticks. the first tissue culture derived vaccine was developed in the early 1970s and this was commercialised as a collaboration between the institute of virology, vienna, austria and immuno ag vienna (now baxter healthcare). this vaccine was highly successful du ...200312628813
inoculation of plasmids encoding japanese encephalitis virus prm-e proteins with colloidal gold elicits a protective immune response in balb/c mice.we established a simple and effective method for dna immunization against japanese encephalitis virus (jev) infection with plasmids encoding the viral prm and e proteins and colloidal gold. inoculation of plasmids mixed with colloidal gold induced the production of specific anti-jev antibodies and a protective response against jev challenge in balb/c mice. when we compared the efficacy of different inoculation routes, the intravenous and intradermal inoculation routes were found to elicit strong ...200312634382
intracellular assembly and secretion of recombinant subviral particles from tick-borne encephalitis is believed that flavivirus assembly occurs by intracellular budding of the nucleocapsid into the lumen of the endoplasmic reticulum (er). recombinant expression of tick-borne encephalitis (tbe) virus envelope proteins prm and e in mammalian cells leads to their incorporation into enveloped recombinant subviral particles (rsps), which have been used as a model system for studying assembly and entry processes and are also promising vaccine candidates. in this study, we analyzed the formation a ...200312634393
antibody and interleukin-12 treatment in murine models of encephalitogenic flavivirus (st. louis encephalitis, tick-borne encephalitis) and alphavirus (venezuelan equine encephalitis) infection.early and sustained treatment with interleukin-12 (il-12) ameliorated disease in a mouse model of infection with the encephalitogenic flavivirus, st. louis encephalitis virus (slev, japanese encephalitis serogroup). however, this effect was not reproduced in murine infections with either the flavivirus tick-bore encephalitis virus (tbev) or the alphavirus venezuelan equine encephalitis virus (veev). il-12 exacerbated tbev disease when used in conjunction with monoclonal antibody (mab), suggestin ...200312639298
cross-protective and infection-enhancing immunity in mice vaccinated against flaviviruses belonging to the japanese encephalitis virus serocomplex.the japanese encephalitis virus serocomplex is a group of mosquito-borne flaviviruses that cause severe encephalitic disease in humans. the recent emergence of several members of this serocomplex in geographic regions where other closely related flaviviruses are endemic has raised urgent human health issues. thus, the impact of vaccination against one of these neurotropic virus on the outcome of infection with a second, serologically related virus is unknown. we show here that immunity against m ...200312639478
interferon alfa-2a in japanese encephalitis: a randomised double-blind placebo-controlled trial.japanese encephalitis virus (jev), although confined to asia, causes about 35000-50000 cases and 10000 deaths every year, and is the most important cause of encephalitis worldwide. there is no known antiviral treatment for any flavivirus. results from in-vitro studies and work in animals have shown inteferon alfa has antiviral activity on japanese encephalitis and other flaviviruses; therefore, we aimed to assess the efficacy of inteferon alfa-2a in japanese encephalitis.200312642049
the importance of being outer: consequences of the distinction between the outer and inner surfaces of flavivirus glycoprotein e.glycoprotein e of west nile, dengue and other flaviviruses is the principal stimulus for the development of neutralizing antibodies and contains a fusion peptide responsible for inserting the virus into the host cell membrane. this glycoprotein lies flat on the surface of the virion and therefore only epitopes on the outer or lateral surface are important immunogens. changes in antigen recognition after exposure of the virus to low ph have yielded clues to the fusion process.200312648938
characterization of rna synthesis, replication mechanism, and in vitro rna-dependent rna polymerase activity of japanese encephalitis vitro rna-dependent rna polymerase assays revealed that the jev replication complex (rc) synthesized viral rna utilizing a semiconservative and asymmetric mechanism. peak viral replicase activity and levels of viral rna observed 15-18 h postinfection (h p.i.) preceded maximum viral titers in the culture medium seen 21 h p.i. among divalent cations, mg(2+) was essential and exhibited cooperative binding for its two replicase-binding sites. mn(2+), despite sixfold higher affinity for the replic ...200312667804
a stable full-length yellow fever virus cdna clone and the role of conserved rna elements in flavivirus replication.yellow fever virus (yf) is the prototype member of the flavivirus genus. here, we report the successful construction of a full-length infectious cdna clone of the vaccine strain yf-17d. yf cdna was cloned into a low-copy-number plasmid backbone and stably maintained in several e. coli strains. transcribed rnas had a specific infectivity of 10(5)-10(6) p.f.u. ( micro g rna)(-1), and the resulting virus exhibited growth kinetics, plaque morphology and proteolytic processing similar to the parental ...200312692292
role of the transmembrane domains of prm and e proteins in the formation of yellow fever virus envelope.flavivirus envelope proteins have been shown to play a major role in virus assembly. these proteins are anchored into cellular and viral membranes by their c-terminal domain. these domains are composed of two hydrophobic stretches separated by a short hydrophilic segment containing at least one charged residue. we investigated the role of the transmembrane domains of prm and e in the envelope formation of the flavivirus yellow fever virus (yfv). alanine scanning insertion mutagenesis has been us ...200312502797
cleavage of protein prm is necessary for infection of bhk-21 cells by tick-borne encephalitis virus.flavivirus particles are synthesized in an immature form containing heterodimers of the proteins prm and e. shortly before release from the cell, prm is cleaved by the host protease furin to yield mature virions. in this study, the furin-mediated cleavage of the tick-borne encephalitis (tbe) virus protein prm was prevented by specific mutagenesis of the cleavage site. this resulted in the production of immature tbe virions, which were shown to be completely non-infectious in bhk-21 cells. this f ...200312533715
characterization of a siberian virus isolated from a patient with progressive chronic tick-borne encephalitis.a strain of tick-borne encephalitis virus designated zausaev (za) was isolated in siberia from a patient who died of a progressive (2-year) form of tick-borne encephalitis 10 years after being bitten by a tick. the complete genomic sequence of this virus was determined, and an attempt was made to correlate the sequence with the biological characteristics of the virus. phylogenetic analysis demonstrated that this virus belongs to the siberian subtype of tick-borne encephalitis virus. comparison o ...200312477807
spontaneous mutations restore the viability of tick-borne encephalitis virus mutants with large deletions in protein c.the capsid protein, c, of tick-borne encephalitis virus has recently been found to tolerate deletions up to a length of 16 amino acid residues that partially removed the central hydrophobic domain, a sequence element conserved among flaviviruses which may be crucial for virion assembly. in this study, mutants with deletion lengths of 19, 21, 27, or 30 residues, removing more or all of this hydrophobic domain, were found to yield viable virus progeny, but this was without exception accompanied by ...200312477849
interferon, ribavirin, 6-azauridine and glycyrrhizin: antiviral compounds active against pathogenic flaviviruses.ribavirin, interferon-alpha (ifn-alpha), 6-azauridine and glycyrrhizin were tested in vitro for their antiviral activities against 11 pathogenic flaviviruses belonging to principal antigenic complexes or individual serogroups of medical importance: dengue, japanese encephalitis, mammalian tick-borne and yellow fever virus (yfv) groups. antiviral activity was estimated by the reduction of the cytopathic effect of each flavivirus in vero cells and by the reduction in virus titer. cytotoxicity was ...200312719009
temperature sensitive mutations in the genes encoding the ns1, ns2a, ns3, and ns5 nonstructural proteins of dengue virus type 4 restrict replication in the brains of mice.using reverse genetics, it is possible to readily add well-defined attenuating mutations to the genome of wild type or incompletely attenuated dengue (den) viruses to generate vaccine candidates that exhibit the desired balance between attenuation and immunogenicity. here, we describe the identification of eight temperature sensitive missense mutations distributed in four non-structural protein genes that specify a 60- to 10,000-fold range of restricted replication in the suckling mouse brain co ...200312721805
viral internal ribosome entry site structures segregate into two distinct increasing number of viruses have been shown to initiate protein synthesis by a cap-independent mechanism involving internal ribosome entry sites (iress). predictions of the folding patterns of these rna motifs have been based primarily on sequence and biochemical analyses. biophysical confirmation of the models has been achieved only for the ires of hepatitis c virus (hcv), which adopts an open structure consisting of two major stems. we have conducted an extensive comparison of flavivirus a ...200312743317
evasion of innate and adaptive immunity by flaviviruses.after a virus infects an animal, antiviral responses are generated that attempt to prevent dissemination. interferons, antibody, complement, t and natural killer cells all contribute to the control and eradication of viral infections. most flaviviruses, with the exception of some of the encephalitic viruses, cause acute disease and do not establish persistent infection. the outcome of flavivirus infection in an animal is determined by a balance between the speed of viral replication and spread, ...200312752684
interaction of flaviviruses with cells of the vertebrate host and decoy of the immune response.flaviviruses cause endemic and epidemic disease with significant morbidity and mortality throughout the world. in contrast to viruses that avoid the host immune response by down-regulating cell surface major histocompatibility complex expression, infection by members of the neurotropic japanese encephalitis serogroup induce virus-directed functional increases in expression of class i and ii major histocompatibility complex and various adhesion molecules, resulting in increased susceptibility to ...200312752685
mhc class i up-regulation by flaviviruses: immune interaction with unknown advantage to host or contrast to many other viruses that escape from cytotoxic t cell recognition by down-regulating major histocompatibility complex class i-restricted antigen presentation, flavivirus infection of mammalian cells up-regulates cell surface expression of major histocompatibility complex class i molecules. two putative mechanisms for flavivirus-induced major histocompatibility complex class i up-regulation, one via activation of the transcription factor nf-kappab, the second by augmentation of pept ...200312752686
is flavivirus resistance interferon type i-independent?interferon type i comprises a group of major virus-inducible host antiviral factors that control infection with a great number of human and animal viruses. they are ubiquitously expressed cytokines that interfere with virus replication within different cell types by activating a number of host genes and several parallel antiviral pathways. two major intracellular actors of ifn-i-induced antiviral states are ribonucleic acid-dependent protein kinase and 2'-5'-oligoadenylate synthetases/rnase l, b ...200312752687
lipophilic derivatization of synthetic peptides belonging to ns3 and e2 proteins of gb virus-c (hepatitis g virus) and its effect on the interaction with model lipid membranes.the synthesis by solid-phase methodologies of peptides belonging to structural and non-structural proteins of gb virus c as well as its n-alpha-acylation with myristate and palmitate fatty acids is described. to explore the peptide-lipid interactions we have used liposomes composed of dipalmitoylphosphatidylcholine as model membranes and complementary spectroscopic and calorimetric techniques. our results show that structural and more clearly the structural lipophilic peptide sequences incorpora ...200312753379
isolation of a new flavivirus related to cell fusing agent virus (cfav) from field-collected flood-water aedes mosquitoes sampled from a dambo in central kenya.cell fusing agent virus (cfav) is an rna insect virus that was isolated from a line of aedes aegypti mosquito cells and has been assigned to the family flaviviridae, genus flavivirus. we report here the first isolation of a cfa-like virus from field-collected mosquitoes. mosquito larvae and pupae were sampled from flooded dambos in central province, kenya during the short rain season of 1999. specimens were reared to adults, identified and pooled by species and were tested for the presence of vi ...200312756616
genetic and phenotypic characterization of the newly described insect flavivirus, kamiti river virus.we have described in the accompanying paper by sang, et al., ([57], arch virol 2003, in press) the isolation and identification of a new flavivirus, kamiti river virus (krv), from ae. macintoshi mosquitoes that were collected as larvae and pupae from flooded dambos in central province, kenya. among known flaviviruses, krv was shown to be most similar to, but genetically and phenotypically distinct from, cell fusing agent virus (cfav). krv was provisionally identified as an insect-only flavivirus ...200312756617
[west nile fever may even be spread to sweden].west nile virus (wnv) is a flavivirus, which was first isolated in uganda 1937. this virus has attracted attention in the past years. wnv is one of the worlds most widespread flaviviruses and has caused recent outbreaks among humans and animals. west nile fever (wnf) is a mosquito borne zoonotic disease. the last decade the epidemiological pattern of the virus and the severity of the outbreaks have changed. this article reviews the epidemiological changes and current situation of wnf, presents a ...200312756695
natural and nosocomial infection in a patient with west nile encephalitis and extrapyramidal movement disorders.since its first recognition in north america in 1999, west nile virus (wnv) has spread rapidly across the continent, but in many communities, rapid diagnostic tests for detection of wnv infection are not fully available. we describe a patient with extrapyramidal movement disorders and changes in the basal ganglia noted on magnetic resonance images that are characteristic of other flavivirus encephalitides and may help in the recognition of patients with west nile encephalitis. detailed molecular ...200312766856
flavivirus capsid is a dimeric alpha-helical protein.the capsid proteins of two flaviviruses, yellow fever virus and dengue virus, were expressed in escherichia coli and purified to near homogeneity suitable for biochemical characterization and structure determination by nuclear magnetic resonance. the oligomeric properties of the capsid protein in solution were investigated. in the absence of nucleic acid, both proteins were predominantly dimeric in solution. further analysis of both proteins with far-uv circular dichroism spectroscopy indicated ...200312768036
structures of immature flavivirus particles.structures of prm-containing dengue and yellow fever virus particles were determined to 16 and 25 a resolution, respectively, by cryoelectron microscopy and image reconstruction techniques. the closely similar structures show 60 icosahedrally organized trimeric spikes on the particle surface. each spike consists of three prm:e heterodimers, where e is an envelope glycoprotein and prm is the precursor to the membrane protein m. the pre-peptide components of the prm proteins in each spike cover th ...200312773377
crystallization and preliminary x-ray diffraction analysis of langat virus envelope protein domain iii.the putative receptor-binding domain (domain iii) of the flavivirus langat envelope glycoprotein has been crystallized using the hanging-drop vapor-diffusion method at 277 k. two distinct crystal morphologies were observed to grow under the same conditions. the crystal forms both belong to a trigonal space group, p3(1)21 or p3(2)21, with unit-cell parameters a = 80.93, c = 132.1 a and a = 104.8, c = 219.5 a for forms i and ii, respectively. complete data sets to 2.9 and 3.35 a, respectively, hav ...200312777770
molecular detection of west nile virus rna.west nile virus is a mosquito-borne flavivirus that is primarily maintained in nature in a mosquito-bird-mosquito transmission cycle. mammals, including humans and horses, are incidentally infected through biting by mosquitoes infected with west nile virus. since 1994, west nile virus outbreaks have occurred with a high incidence of severe disease in humans and horses. in the usa, west nile virus was first detected in 1999 in new york city and has since spread to 39 states in humans. the virus h ...200312779009
traditional and novel approaches to flavivirus vaccines.yellow fever, dengue, japanese encephalitis and tick-borne encephalitis viruses are the medically most important members of the flavivirus genus composed primarily of arboviruses. in this paper, we review the commercially available traditional flavivirus vaccines against yellow fever, japanese encephalitis, and tick-borne encephalitis, as well as modern approaches to flavivirus vaccines. formalin inactivation technology has been employed to produce killed vaccines. flaviviruses have been attenua ...200312782056
dendritic-cell-specific icam3-grabbing non-integrin is essential for the productive infection of human dendritic cells by mosquito-cell-derived dengue viruses.dengue virus (dv) is a mosquito-borne flavivirus that causes haemorrhagic fever in humans. dv primarily targets immature dendritic cells (dcs) after a bite by an infected mosquito vector. here, we analysed the interactions between dv and human-monocyte-derived dcs at the level of virus entry. we show that the dc-specific icam3-grabbing non-integrin (dc-sign) molecule, a cell-surface, mannose-specific, c-type lectin, binds mosquito-cell-derived dvs and allows viral replication. conclusive evidenc ...200312783086
poliomyelitis and flaviviruses. 200312783413
comparative population dynamics of mosquito-borne flaviviruses.among the members of the genus flavivirus are several important human pathogens, including the dengue (den) and japanese encephalitis (je) viruses. from the analysis of gene sequence data of samples of these virus populations it is possible to infer phylogenetic relationships, which in turn can yield important epidemiological information, including their demographic history in humans. in this study, we use a recently developed method, based on coalescent theory, to infer the population dynamics ...200312809802
the membrane proteins of flaviviruses form ion-permeable pores in the target membrane after fusion: identification of the pores and analysis of their possible role in virus infection.recently, we presented evidence that the e1 fusion protein of the alphavirus semliki forest virus forms ion-permeable pores in the target membrane after fusion. we proposed that the homologous fusion proteins of flaviviruses and hepatitis c virus form similar pores. to test this hypothesis for the e fusion protein of flaviviruses, the release of [(3)h]choline from liposomes by the flavivirus west nile (wn) virus was determined. [(3)h]choline was released at mildly acid ph. the ph threshold depen ...200312810864
antibody-dependent enhancement of murray valley encephalitis virus virulence in mice.enhancement of flavivirus infection in vitro in the presence of subneutralizing concentrations of homologous or heterologous antiserum has been well described. however, the importance of this phenomenon in the enhancement of flavivirus infection in vivo has not been established. in order to study antibody-mediated enhancement of flavivirus infection in vivo, we investigated the effect of passive immunization of mice with japanese encephalitis virus (je) antiserum on the outcome of infection with ...200312810865
distribution of three arbovirus antibodies among monkeys (macaca fascicularis) in the philippines.serum samples from 54 monkeys were collected from healthy individuals in a monkey farm in luzon island, philippines, in 1999, and examined by igm-capture elisa and indirect igg elisa for the presence of dengue (den), japanese encephalitis (je) and chikungunya (chik) viruses. the positive rates for igm elisa were 3.7, 35.2 and 14.8% against den, je and chik, respectively. higher positive rates were obtained when indirect igg elisa was used: 100% against flaviviruses (je or den) and 59.3% against ...200312823631
development of a quantitative real-time rt-pcr assay with internal control for the laboratory detection of tick borne encephalitis virus (tbev) rna.tick borne encephalitis virus (tbev), is a human flavivirus causing tick borne encephalitis (tbe), a viral infection of the central nervous system endemic in europe and asia.200312829035
kunjin virus replicon vectors for human immunodeficiency virus vaccine development.we have previously demonstrated the ability of the vaccine vectors based on replicon rna of the australian flavivirus kunjin (kun) to induce protective antiviral and anticancer cd8+ t-cell responses using murine polyepitope as a model immunogen (i. anraku, t. j. harvey, r. linedale, j. gardner, d. harrich, a. suhrbier, and a. a. khromykh, j. virol. 76:3791-3799, 2002). here we showed that immunization of balb/c mice with kun replicons encoding hiv-1 gag antigen resulted in induction of both gag- ...200312829819
molecular and functional analyses of kunjin virus infectious cdna clones demonstrate the essential roles for ns2a in virus assembly and for a nonconservative residue in ns3 in rna replication.a number of full-length cdna clones of kunjin virus (kun) were previously prepared; it was shown that two of them, pakun and flsdx, differed in specific infectivities of corresponding in vitro transcribed rnas by approximately 100,000-fold (a. a. khromykh et al., j. virol. 72:7270-7279, 1998). in this study, we analyzed a possible genetic determinant(s) of the observed differences in infectivity initially by sequencing the entire cdnas of both clones and comparing them with the published sequenc ...200312829820
involvement of lipids in different steps of the flavivirus fusion mechanism.flavivirus membrane fusion is triggered by acidic ph and mediated by the major envelope protein e. a structurally very similar fusion protein is found in alphaviruses, and these molecules are designated class ii viral fusion proteins. in contrast to that of flaviviruses, however, alphavirus fusion has been shown to be absolutely dependent on the presence of cholesterol and sphingomyelin in the target membrane, suggesting significant differences in the fusion protein-membrane interactions that le ...200312829825
clinical and laboratory findings on the first imported case of murray valley encephalitis in europe.murray valley encephalitis (mve) is an important mosquitoborne flavivirus infection endemic to australia and papua new guinea. we report the first imported case of mve in europe. a 23-year-old tourist developed severe encephalitis after having returned to germany from a long-term trip across the australian continent. the diagnosis was suspected on the basis of clinical findings and the patient's travel history and was confirmed by serological findings. the patient made a prolonged but complete r ...200312856229
managing occupational risks for hepatitis c transmission in the health care setting.hepatitis c virus (hcv) infection is a significant contemporary health problem in the united states and elsewhere. because it is primarily transmitted via blood, hepatitis c infection presents risks for both nosocomial transmission to patients and occupational spread to health care workers. recent insights into the pathogenesis, immunopathogenesis, natural history, and treatment of infection caused by this unique flavivirus provide a rationale for the use of new strategies for managing occupatio ...200312857782
dengue virus type 2 ns3 protease and ns2b-ns3 protease precursor induce apoptosis.apoptosis was detected in vero cell cultures expressing transfected dengue virus type 2 (denv-2) genes. approximately 17.5 and 51.5 % of cells expressing ns3 serine protease and ns2b-ns3(185) serine protease precursor protein [ns2b-ns3(185)(pro)] genes, respectively, were apoptotic. the percentage of apoptotic cells was significantly higher in cell cultures expressing ns2b-ns3(185)(pro). ns2b-ns3(185)(pro) was detected as ns2b-ns3(185)(pro)-egfp fusion protein in cytoplasmic vesicular structures ...200312867651
novel, potent phenethylamide inhibitors of the hepatitis c virus (hcv) ns3 protease: probing the role of p2 aryloxyprolines with hybrid structures.synthesis of hybrid hcv ns3 protease/ns4a inhibitors having the 4,4-difluoroaminobutyric acid (difluoroabu) phenethylamides as p1-p1' and quinolyloxyprolines as p2 fragments led to 7 (ic(50) 54 nm). molecular modelling suggests that this potent tripeptide inhibitor utilizes interactions in the s1', s1, s2, s3 and s4 sites of the protease.200312873506
tick-borne encephalitis: a retrospective study of clinical cases in bornholm, denmark.tick-borne encephalitis (tbe) is caused by a flavivirus, tick-borne encephalitis virus (tbev). for decades tbe has been known to cause disease in bornholm, a danish island. a retrospective study was performed to identify undiagnosed cases of tbe among patients hospitalized with signs and symptoms of meningitis or encephalitis in the 5 y period 1994-1999. this investigation revealed 5 new, and initially undiagnosed cases of tbe. in total, 14 cases of tbe were found in the 7 y period 1994-2000; 2 ...200312875531
incorporation of tick-borne encephalitis virus replicons into virus-like particles by a packaging cell line.rna replicons derived from flavivirus genomes show considerable potential as gene transfer and immunization vectors. a convenient and efficient encapsidation system is an important prerequisite for the practical application of such vectors. in this work, tick-borne encephalitis (tbe) virus replicons and an appropriate packaging cell line were constructed and characterized. a stable cho cell line constitutively expressing the two surface proteins prm/m and e (named cho-me cells) was generated and ...200312885909
brazilian flavivirus phylogeny based on this work, a comprehensive phylogenetic study based on 600 base pair nucleotide and on putative 200 amino acid sequences of ns5 was carried out in order to establish genetic relationships among 15 strains of 10 brazilian flaviviruses: bussuquara, cacipacore, dengue type 1, 2 and 4, iguape, ilheus, rocio, saint louis encephalitis (sle), and yellow fever. phylogenetic trees were created by neighbor-joining and maximum parsimony methods. these trees showed brazilian flaviviruses grouped into thr ...200312886419
alteration of clinical outcome and histopathology of yellow fever virus infection in a hamster model by previous infection with heterologous flaviviruses.using a recently described hamster model of severe yellow fever (yf), we examined the hypothesis that prior infection with heterologous flaviviruses protects against severe or fatal yf. hamsters were singly or sequentially infected with japanese encephalitis, st. louis encephalitis, west nile, and/or dengue-1 viruses, and then challenged with a virulent strain of yellow fever virus (yfv). in contrast to control (naive) hamsters, many of which appeared clinically ill or died after yfv infection, ...200312887029
acute undifferentiated fever caused by infection with japanese encephalitis determine the proportion of acute undifferentiated fevers without neurologic deficits related to infection with japanese encephalitis (je) virus, flavivirus serology (dengue and je) was performed in a cohort of 156 adults presenting to a hospital in chiangrai, thailand. recent flavivirus infection was diagnosed for any individual with an igm result > 40 units. a ratio of dengue virus igm to je virus igm < 0.91 defined a je virus infection. diagnostic criteria for japanese encephalitis were me ...200312887030
a trade-off in replication in mosquito versus mammalian systems conferred by a point mutation in the ns4b protein of dengue virus type acceptable live-attenuated dengue virus vaccine candidate should have low potential for transmission by mosquitoes. we have identified and characterized a mutation in dengue virus type 4 (den4) that decreases the ability of the virus to infect mosquitoes. a panel of 1248 mutagenized virus clones generated previously by chemical mutagenesis was screened for decreased replication in mosquito c6/36 cells but efficient replication in simian vero cells. one virus met these criteria and contained a ...200312890635
[specific determination of flaviviruses by molecular hybridization with synthetic deoxyoligonucleotide probes].molecular probes were designed for the purpose of specific determination of flavioviruses transmitted by the ticks of tick-borne encephalitis (tbe) and omsk hemorrhagic fever (ohv) as well as by mosquitoes of japanese encephalitis (je), north nile (nn), murrey valley encephalitis (mve), saint-lois encephalitis (sle), dengue 1-4 and of yellow fever (yf). the probes are synthetic deoxyoligonucleotides with the 18-20 long basis and complementary for the rna fragments defined by computer analysis. t ...200312894476
antigen-expressed recombinant salmonella typhimurium driven by an in vivo-activated promoter is capable of inducing cellular immune response in transgenic explore the approaches and mechanisms for reversing the immune tolerance in transgenic mouse, and the pathogenicity of hepatitis g virus (hgv), the promoter of phop-activated gene (p(pagc)) of salmonella typhimurium was used as a transcriptionally regulating element to construct an attenuated s. typhimurium expressing hgv ns3. the recombinant s. typhimurium was orally administered to hgv transgenic mice. as the results, hgv antigen in serum and liver as well as hgv mrna in liver were decrease ...200312897963
screening for t cell-eliciting proteins of japanese encephalitis virus in a healthy je-endemic human cohort using recombinant baculovirus-infected insect cell preparations.the analysis of cell-mediated immune responses in virus-exposed but healthy individuals may contribute to define the features of the t cell response associated with resistance. we report, for the first time, on adaptive t cell responses to 5 largest of the 10 proteins that together constitute 76% of the coding potential of the japanese encephalitis virus (jev) genome in a naturally exposed healthy je-immune human cohort. fixed and sonified whole cell preparations of insect cells individually exp ...200312898332
hepatitis c: a review.hepatitis c virus is an rna virus in the flavivirus family that was identified in 1989. since then, blood donor screening has reduced the incidence of acute infections; however, because this virus frequently leads to asymptomatic chronic infection, the prevalence of infection remains high. chronic infection leads to increased risks of cirrhosis and hepatocellular carcinoma, as well as extrahepatic manifestations. guidelines for widespread screening continue to evolve, and early diagnosis is like ...200312900622
discrimination of west nile virus and japanese encephalitis virus strains using rt-pcr rflp analysis.west nile (wn) virus is a mosquito-borne flavivirus that induces lethal encephalitis in humans and horses. since an outbreak of wn encephalitis in humans and horses occurred in new york city in late august 1999, the possibility exists that wn virus will invade regions that have close links with the united states, such as japan. we developed a genetic diagnostic method that discriminates between strains of wn virus and japanese encephalitis (je) virus. the method involves rt-pcr restriction fragm ...200312906104
chronic hepatitis associated with gb virus b persistence in a tamarin after intrahepatic inoculation of synthetic viral rna.progress in understanding the pathogenesis of hepatitis c virus (hcv) has been slowed by the absence of tractable small animal models. whereas gb virus b (gbv-b, an unclassified flavivirus) shares a phylogenetic relationship and several biologic attributes with hcv, including hepatotropism, it is not known to cause persistent infection, a hallmark of hcv. here, we document persistent gbv-b infection in one of two healthy tamarins (saguinus oedipus) inoculated intrahepatically with infectious syn ...200312907703
characterization of rna-dependent rna polymerase activity of csfv ns5b proteins expressed in escherichia coli.the full-length ns5b protein, and the truncated ns5b proteins of classical swine fever virus (csfv) resulted from deletion of 24, 36, 65 or 82, amino acid residues at the c terminal were expressed in escherichia coli cells and purified with a c-terminal hexahistidine tag. in addition to the full-length ns5b protein, those truncated ns5b proteins with deletion of 24, 36, or 65 amino acid residues were demonstrated to have rna-dependent rna polymerase (rdrp) activity, which was not found in the tr ...200312913359
mr findings in murray valley encephalitis.murray valley encephalitis (mve) is caused by a flavivirus related to west nile and st. louis encephalitis viruses. we report a case of mve resulting in quadriplegia and respiratory failure. mr imaging demonstrated thalamic hyperintensity on t2-weighted images, with similar involvement of the red nucleus, substantia nigra, and cervical cord. these findings preceded serologic diagnosis and are similar to those of japanese encephalitis. in the appropriate setting, thalamic t2 hyperintensity is sug ...200312917132
evidence for antigen production in muscles by dengue and japanese encephalitis dna vaccines and a relation to their immunogenicity in mice.this study demonstrated viral antigen production in muscle tissues following inoculation with dna vaccines and examined its relation to antibody induction in mice using the flavivirus system. to achieve detectable levels of antigen production, we used a needle-free jet injector and examined 10% homogenate of quadriceps muscle for viral antigens in a sandwich enzyme-linked immunosorbent assay. we compared dna vaccines against dengue type 1 (designated pcd1me), dengue type 2 (pcd2me) and japanese ...200312922102
induction of cross-protection against two wild-type taiwanese isolates of japanese encephalitis virus using beijing-1 strain dna vaccine.japanese encephalitis virus (jev), a mosquito-borne flavivirus, is an important human pathogen. mouse brain-derived, inactivated jev vaccines have contributed greatly to the reduction in numbers of je patients in several countries, including taiwan. however, mice immunized with the nakayama strain inactivated vaccine show lower protection against a lethal strain of beijing-1 jev than those immunized with the homologous vaccine. dna vaccine encoding the envelope (e) protein gene appears to provid ...200312922129
large genetic differentiation and low variation in vector competence for dengue and yellow fever viruses of aedes albopictus from brazil, the united states, and the cayman islands.we conducted a population genetic analysis of aedes albopictus collected from 20 sites in brazil, the united states (florida, georgia, and illinois), and the cayman islands. using isoenzyme analysis, we examined genetic diversity and patterns of gene flow. high genetic differentiation was found among brazilian samples, and between them and north american samples. regression analysis of genetic differentiation according to geographic distances indicated that ae. albopictus samples from florida we ...200312932107
growth characteristics of the veterinary vaccine candidate chimerivax-west nile (wn) virus in aedes and culex 1999 west nile (wn) virus was introduced to north america where this flavivirus has spread rapidly among wildlife (especially birds) transmitted by various species of mosquitoes (diptera: culicidae). increasing numbers of cases and deaths among humans, horses and other domestic animals require development of effective vaccines. 'chimerivax-west nile(vet)' is being developed for use as a veterinary vaccine to protect against wn infection. this chimeric virus contains the pre-membrane (prm) and ...200312941006
functional analysis of mosquito-borne flavivirus conserved sequence elements within 3' untranslated region of west nile virus by use of a reporting replicon that differentiates between viral translation and rna replication.we have developed a reporting replicon of west nile virus (wnv) that could be used to quantitatively distinguish viral translation and rna replication. a renilla luciferase (rluc) gene was fused in-frame with the open reading frame of a subgenomic replicon in the position where the viral structural region was deleted, resulting in rlucrep. transfection of bhk cells with rlucrep rna yielded two distinctive rluc signal peaks, one between 2 and 10 h and the other after 26 h posttransfection. by con ...200312941911
acute encephalitis, a poliomyelitis-like syndrome and neurological sequelae in a hamster model for flavivirus infections.infection of hamsters with the murine flavivirus modoc results in (meningo)encephalitis, which is, during the acute phase, frequently associated with flaccid paralysis, as also observed in patients with west nile virus encephalitis. twenty percent of the hamsters that recover from the acute encephalitis develop life-long neurological sequelae, reminiscent of those observed, for example, in survivors of japanese encephalitis. magnetic resonance imaging and histology revealed severe lesions predom ...200312946018
analysis of the complete genome of the tick-borne flavivirus omsk hemorrhagic fever virus.omsk hemorrhagic fever virus (ohf) is a tick-borne flavivirus endemic to western siberia. this virus is the only known tick-borne flavivirus to cause hemorrhagic disease in humans in the absence of encephalitis. ohf virus circulates within a small, defined niche in which other tick-borne complex flaviviruses are also present. the objectives of this study were to genetically classify ohf virus based on its complete genome and to identify genetic determinants that might be involved in tissue tropi ...200312951023
west nile virus in the united states: an update on an emerging infectious disease.west nile virus is a mosquito-borne flavivirus and human neuropathogen. since the virus was recognized in new york city in 1999, it has spread rapidly across the united states, with human disease documented in 39 states and the district of columbia. west nile virus can cause a broad range of clinical syndromes, including fever, meningitis, encephalitis, and a flaccid paralysis characteristic of a poliomyelitis-like syndrome. approximately one in 150 infections results in severe neurologic illnes ...200312952382
structural basis of a flavivirus recognized by its neutralizing antibody: solution structure of the domain iii of the japanese encephalitis virus envelope protein.the flavivirus envelope protein is the dominant antigen in eliciting neutralizing antibodies and plays an important role in inducing immunologic responses in the infected host. we have determined the solution structure of the major antigenic domain (domain iii) of the japanese encephalitis virus (jev) envelope protein. the jev domain iii forms a beta-barrel type structure composed of six antiparallel beta-strands resembling the immunoglobulin constant domain. we have also identified epitopes of ...200312952958
immunoassay targeting nonstructural protein 5 to differentiate west nile virus infection from dengue and st. louis encephalitis virus infections and from flavivirus vaccination.west nile virus (wnv) is an emerging flavivirus that has caused frequent epidemics since 1996. besides natural transmission by mosquitoes, wnv can also be transmitted through blood transfusion and organ transplantation, thus heightening the urgency of development of a specific and rapid serologic assay of wnv infection. the current immunoassays lack specificity because they are based on detection of antibodies against wnv structural proteins and immune responses to structural proteins among flav ...200312958248
diagnosis of tick-borne encephalitis by a mu-capture immunoglobulin m-enzyme immunoassay based on secreted recombinant antigen produced in insect cells.acute tick-borne encephalitis is diagnosed by detection of igm antibodies to tick-borne encephalitis virus (tbev) (genus flavivirus) in patient serum. tbev membrane (m) and envelope (e) proteins have previously been shown to form virus-like particles when expressed in mammalian cells. we expressed the prm/m and e proteins in insect cells with a recombinant baculovirus system and obtained antigenic protein secreted into the cell culture medium, as evidenced by detection by a panel of five monoclo ...200312958266
west nile virus: epidemiology, clinical presentation, diagnosis, and prevention.west nile virus was recognized in the united states for the first time in 1999, when it caused an epidemic of encephalitis and meningitis in new york city, ny. since then, the disease has been steadily moving westward, and human cases were recognized in 39 states and the district of columbia in 2002. the infection is caused by a flavivirus that is transmitted from birds to humans through the bite of culicine mosquitoes. most infections are mild, with symptoms primarily being fever, headache, and ...200312962168
characterization of resistance to non-obligate chain-terminating ribonucleoside analogs that inhibit hepatitis c virus replication in vitro.the urgent need for efficacious drugs to treat chronic hepatitis c virus (hcv) infection requires a concerted effort to develop inhibitors specific for virally encoded enzymes. we demonstrate that 2'-c-methyl ribonucleosides are efficient chain-terminating inhibitors of hcv genome replication. characterization of drug-resistant hcv replicons defined a single s282t mutation within the active site of the viral polymerase that conferred loss of sensitivity to structurally related compounds in both ...200312966103
proteasome activator pa28gamma-dependent nuclear retention and degradation of hepatitis c virus core protein.hepatitis c virus (hcv) core protein plays an important role in the formation of the viral nucleocapsid and a regulatory protein involved in hepatocarcinogenesis. in this study, we have identified proteasome activator pa28gamma (11s regulator gamma) as an hcv core binding protein by using yeast two-hybrid system. this interaction was demonstrated not only in cell culture but also in the livers of hcv core transgenic mice. these findings are extended to human hcv infection by the observation of t ...200312970408
significance in replication of the terminal nucleotides of the flavivirus genome.point mutations that resulted in a substitution of the conserved 3'-penultimate cytidine in genomic rna or the rna negative strand of the self-amplifying replicon of the flavivirus kunjin virus completely blocked in vivo replication. similarly, substitutions of the conserved 3'-terminal uridine in the rna negative or positive strand completely blocked replication or caused much-reduced replication, respectively. the same preference for cytidine in the 3'-terminal dinucleotide was noted in report ...200312970446
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