Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| 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. | 2003 | 12648938 |
| 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 ... | 2003 | 12502797 |
| 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 ... | 2003 | 12692292 |
| 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 ... | 2003 | 12477807 |
| stable rna structures can repress rna synthesis in vitro by the brome mosaic virus replicase. | a 15-nucleotide (nt) unstructured rna with an initiation site but lacking a promoter could direct the initiation of rna synthesis by the brome mosaic virus (bmv) replicase in vitro. however, bmv rna with a functional initiation site but a mutated promoter could not initiate rna synthesis either in vitro or in vivo. to explain these two observations, we hypothesize that rna structures that cannot function as promoters could prevent rna synthesis by the bmv rna replicase. we documented that four d ... | 2003 | 12702814 |
| role of heparan sulfate for attachment and entry of tick-borne encephalitis virus. | attachment of the flavivirus tick-borne encephalitis (tbe) virus to different permissive cell lines was investigated by a newly established quantitative assay using fluorescence-labeled virus. previous work had shown that bhk-21 cell-adapted mutants of tbe virus had acquired potential heparan sulfate (hs) binding sites on the outer surface of protein e. quantitative analysis of one of these mutants indicated that it attached to hs-expressing cell lines with a 10- to 13-fold higher affinity than ... | 2003 | 12706093 |
| [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. | 2003 | 15340542 |
| suramin inhibits the in vitro expression of encephalitis b virus proteins ns3 and e. | in 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 ... | 2003 | 15015640 |
| serologic evidence of west nile virus infection in black bears (ursus americanus) from new jersey. | serum samples obtained from 51 free-ranging black bears (ursus americanus) in northwestern new jersey in february and march 2002 were analyzed for neutralizing antibodies to west nile virus (wnv) and st. louis encephalitis virus. three (6%) of the black bears tested positive for wnv-neutralizing antibodies. one additional sample was positive for flavivirus-neutralizing antibodies but could not be differentiated for a specific virus type. this is the first report of wnv infection in black bears. | 2003 | 14733286 |
| prospects for antiviral therapy. | 2003 | 14714442 | |
| 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 ... | 2003 | 14714441 |
| 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 ... | 2003 | 14700342 |
| serodiagnosis of flaviviral infections and vaccinations in humans. | 2003 | 14714429 | |
| 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 ... | 2003 | 14714430 |
| 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 ... | 2003 | 14714436 |
| epidemiology of other arthropod-borne flaviviruses infecting humans. | 2003 | 14714437 | |
| 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 ... | 2003 | 14714438 |
| dna vaccines for flaviviruses. | 2003 | 14714440 | |
| molecular biology of flaviviruses. | 2003 | 14696326 | |
| flavivirus structure and membrane fusion. | 2003 | 14696327 | |
| kunjin rna replication and applications of kunjin replicons. | the kunjin virus (kunv) has provided a useful laboratory model for flavivirus rna replication. the synthesis of progeny rna(+) strands occurs via asymmetric and semiconservative replication on a template of recycling double-stranded rna (dsrna) or replicative form (rf). kinetics of viral rna synthesis indicated a cycle period of about 15 min during which, on average, a single nascent rna (+) strand displaces the pre-existing rna(+) strand in the replicative intermediate. data on the composition ... | 2003 | 14696328 |
| manipulation of cell surface macromolecules by flaviviruses. | cell surface macromolecules play a crucial role in the biology and pathobiology of flaviviruses, both as receptors for virus entry and as signaling molecules for cell-cell interactions in the processes of vascular permeability and inflammation. this review examines the cell tropism and pathogenesis of flaviviruses from the standpoint of cell surface molecules, which have been implicated as receptors in both virus-cell as well as cell-cell interactions. the emerging picture is one that encompasse ... | 2003 | 14696331 |
| origins, evolution, and vector/host coadaptations within the genus flavivirus. | although viruses in the genus flavivirus share complex antigenic interrelationships, they can be divided into four phylogenetic/ecological groups: two mosquito-borne groups, a tick-borne group, and nonvectored viruses. these divisions largely reflect the selective constraints imposed on the viruses by the vertebrate hosts, the invertebrate vectors, and the associated ecologies. phylogenetic trees based on the flavivirus genetic sequence show characteristic branching patterns that reflect these g ... | 2003 | 14696332 |
| antigenic structure of flavivirus proteins. | the increased activity of dengue virus in the tropical regions of the world and the recent movement of west nile virus from the eastern to the western hemisphere emphasize the fact that vector-borne flaviviruses are medically important emerging infectious diseases. these facts warrant continued efforts to decode all facets of flavivirus immunology. this chapter reviews current understanding of the antigenic fine structure of flaviviral structural and nonstructural (ns) proteins and their involve ... | 2003 | 14696329 |
| 5'- and 3'-noncoding regions in flavivirus rna. | 2003 | 14696330 | |
| molecular determinants of virulence: the structural and functional basis for flavivirus attenuation. | 2003 | 14689690 | |
| genetic resistance to flaviviruses. | resistance to flavivirus-induced disease in mice was first discovered in the 1920s and was subsequently shown to be controlled by the resistant allele of a single dominant autosomal gene. while the majority of current laboratory mouse stains have a homozygous-susceptible phenotype, the resistant allele has been found to segregate in wild mouse populations in many different parts of the world. resistance is flavivirus specific and extends to both mosquito- and tick-borne flaviviruses. resistant a ... | 2003 | 14689691 |
| immunobiology of mosquito-borne encephalitic flaviviruses. | 2003 | 14689692 | |
| immune modulation by flaviviruses. | flaviviruses cause pleomorphic disease with significant morbidity and mortality worldwide. interestingly, in contrast to most viruses, which subvert or avoid host immune systems, members of the neurotropic japanese encephalitis serocomplex cause functional changes associated with increased efficacy of the immune response. these viruses induce increased cell surface expression of immune recognition molecules, including class i and ii major histocompatibility complex (mhc) and various adhesion mol ... | 2003 | 14689693 |
| 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 ... | 2003 | 12533715 |
| architecture of the flaviviral replication complex. protease, nuclease, and detergents reveal encasement within double-layered membrane compartments. | flavivirus infection causes extensive proliferation and reorganization of host cell membranes to form specialized structures called convoluted membranes/paracrystalline arrays and vesicle packets (vp), the latter of which is believed to harbor flaviviral replication complexes. using detergents and trypsin and micrococcal nuclease, we provide for the first time biochemical evidence for a double membrane compartment that encloses the replicative form (rf) rna of the three pathogenic flaviviruses w ... | 2003 | 12700232 |
| recent advances in japanese encephalitis. | japanese encephalitis (je), the most important cause of epidemic encephalitis worldwide, is confined to asia, but its geographical area is spreading. west nile virus, and other closely related flaviviruses, cause similar disease elsewhere. recent cryoelectron microscopic studies have characterized the flavivirus envelope protein as a new class of viral fusion protein (class ii), and examined its arrangement on the virion surface. changes in the envelope protein's hinge region, or its putative re ... | 2003 | 12707858 |
| 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 ... | 2003 | 12721805 |
| viral internal ribosome entry site structures segregate into two distinct morphologies. | an 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 ... | 2003 | 12743317 |
| the extent of homologous recombination in members of the genus flavivirus. | the family flaviviridae includes important human pathogens, such as dengue (den) virus, yellow fever (yf) virus and hepatitis c virus, many of which have emerged or re-emerged in recent years. until recently, flavivirus evolution was thought to proceed in a clonal manner, with diversity generated mainly through the accumulation of mutational changes. however, this assumption has now been shown to be invalid, with homologous recombination demonstrated in all three genera of the flaviviridae: sinc ... | 2003 | 12560576 |
| a rapid and convenient variant of fusion-pcr to construct chimeric flaviviruses. | so far, full-length cdnas of chimeric flaviviruses have been constructed by restriction-enzyme cleavage of the gene(s) to be exchanged or by fusion-pcr of two amplified pcr fragments. the construction of a chimeric flavivirus by a faster and more convenient variant of the standard fusion-pcr is reported. a modoc/yellow fever chimeric virus was engineered in which the structural prm and e genes of yellow fever virus 17d were replaced by the homologous genes of modoc virus. in two pcr steps, a fus ... | 2003 | 12565155 |
| impact of direct virus-induced neuronal dysfunction and immunological damage on the progression of flavivirus (modoc) encephalitis in a murine model. | flavivirus encephalitis is believed to be the result of two main mechanisms: (i) direct damage to and dysfunction of neurons as a result of viral replication and (ii) destruction of the brain tissue by an inflammatory response. the differential impact of both mechanisms on the progression of flavivirus encephalitis has not been clearly determined. we have now studied the encephalitis caused by modoc virus (modv) infection in (i) severe combined immunodeficiency (scid) mice, (ii) immunocompetent ... | 2003 | 12587070 |
| 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 ... | 2003 | 12756616 |
| 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 ... | 2003 | 14710742 |
| [the alkhurma virus (family flaviviridae, genus flavivirus): an emerging pathogen responsible for hemorrhage fever in the middle east]. | to date tick-borne flaviviruses causing hemorrhagic fevers in humans have been isolated in siberia (omsk hemorrhagic fever virus), india (kyasanur forest disease virus), and saudi arabia (akhurma virus). because of their potential use as biological weapons for bioterrorism, these 3 viruses require level 4 biosafety handling facilities and have been listed as hypervirulent pathogens by the center for disease control and prevention. alkhurma virus was isolated in 1995 from patients with hemorrhagi ... | 2003 | 14579470 |
| evolutionary relationship between old world west nile virus strains. evidence for viral gene flow between africa, the middle east, and europe. | little is known about the genetic relationships between european and other old-world strains of west nile virus (wnv) and persistence of wnv north of mediterranean. we characterized the complete genomes of three wnv strains from france (horse-2000), tunisia (human-1997) and kenya (mosquito-1998), and the envelope, ns3 and ns5 genes of the koutango virus. phylogenetic analyses including all available full-length sequences showed that: (1) koutango virus is a distant variant of wnv; (2) the three ... | 2003 | 14585341 |
| serologic diagnosis of west nile virus infection. | the epidemic of west nile virus (wnv) in the usa in 2002 represents the largest outbreak of meningoencephalitis in the western hemisphere ever reported. besides natural transmission by mosquitoes, five new modes of wnv transmission to humans have been reported: blood transfusion, organ transplantation, transplacental transmission, breastfeeding and laboratory-acquired infection. the recognition of these new transmission routes has made the development of rapid and accurate serological diagnosis ... | 2003 | 14628901 |
| antibody prophylaxis and therapy against west nile virus infection in wild-type and immunodeficient mice. | west nile virus (wnv) is a mosquito-borne flavivirus that causes encephalitis in a subset of susceptible humans. current treatment for wnv infections is supportive, and no specific therapy or vaccine is available. in this study, we directly tested the prophylactic and therapeutic efficacy of polyclonal antibodies against wnv. passive administration of human gamma globulin or mouse serum prior to wnv infection protected congenic wild-type, b-cell-deficient ( micro mt), and t- and b-cell-deficient ... | 2003 | 14645550 |
| protection of mice against experimental japanese encephalitis virus infections by neutralizing anti-glycoprotein e monoclonal antibodies. | neutralizing monoclonal antibodies (mabs) to glycoprotein e (gpe) of japanese encephalitis (je) virus given intraperitoneally (i.p.) (0.1 ml of immune ascitic fluid (af) diluted 1:10 per mouse) to about 4-week-old swiss mice 1 day prior or 2 days after the virus challenge (100 ld50 of je virus administered intracerebrally (i.c.)) resulted in a decreased mortality along with an increased survival of the animals as demonstrated by the hai-positive virus-specific (hs) mabs. the protective effect pr ... | 2003 | 14658841 |
| vaccinia virus recombinant expressing gene of tick-borne encephalitis virus non-structural ns1 protein elicits protective activity in mice. | a vaccinia virus recombinant containing the non-structural tick-borne encephalitis virus (tbev) ns1 gene was developed. the recombinant expressed native dimeric form of the ns1 protein in infected cells and protected mice against lethal infection with tbev. | 2003 | 14687719 |
| preface to the flaviviruses. | 2003 | 14689688 | |
| preface to volume 60 the flaviviruses: pathogenesis and immunity. | 2003 | 14689689 | |
| ns2a-ns2b sequence analysis of den-4 virus strains. | to 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 ... | 2003 | 15115127 |
| 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 ... | 2003 | 14740952 |
| serologic evidence of west nile virus infection in birds, tamaulipas state, méxico. | following the introduction of west nile virus (wnv) into north america in 1999, surveillance for wnv in migratory and resident birds was established in tamaulipas state, northern méxico in december 2001. overall, 796 birds representing 70 species and 10 orders were captured and assayed for antibodies to wnv. nine birds had flavivirus-specific antibodies by epitope-blocking enzyme-linked immunosorbent assay; four were confirmed to have antibody to wnv by plaque reduction neutralization test. the ... | 2003 | 14733673 |
| dynamics of flavivirus infection in mosquitoes. | 2003 | 14689695 | |
| dynamics of infection in tick vectors and at the tick-host interface. | tick-borne flaviviruses are common, widespread, and successfully adapted to their mode of transmission. most tick vectors of flaviviruses are ixodid species. these ticks are characterized by a comparatively long life cycle, lasting several years, during which the infecting virus may be maintained from one developmental stage of the tick to the next. hence ticks act as highly efficient reservoirs of flaviviruses. many tick-borne flaviviruses are transmitted vertically, from adult to offspring, al ... | 2003 | 14689696 |
| pathogenesis of flavivirus encephalitis. | 2003 | 14689697 | |
| 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 ... | 2003 | 14740955 |
| 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 ... | 2003 | 14740953 |
| [abundance indices of larvae and pupae of aedes aegypti (diptera: culicidae) in córdoba city]. | in 1995, aedes aegypti, vector of the flavivirus dengue and yellow fever, reached the province. therefore, it is necessary to quantify the vector abundance in order to determine the level of risk and to evaluate the prevention and control actions implemented. | 2003 | 16724440 |
| west nile virus infection in the united states: overview as a public health issue. | in august 1999, west nile virus (wnv), a mosquito-transmitted flavivirus, appeared in new york city. this represented the first time a major outbreak of this old world virus caused an epidemic in the western hemisphere. by december 2002, the outbreak had spread, probably via avian migratory flyways, to involve 44 states and the district of columbia. the future epidemiology of wnv infection in the united states will be difficult to forecast. in the absence of an effective human vaccine, the only ... | 2003 | 21765762 |
| [west nile fever]. | west nile fever is a mosquito-borne febrile illness seen in africa, asia, and europe, but reported in north america only once. west nile virus is of the family flaviviridae, genus flavivirus. several west nile fever outbreaks were reported from israel in the 1950s and in 1980. since the mid-1990s, frequency and apparent clinical severity of west nile virus outbreaks have increased. outbreaks in rumania (1996), russia (1999), and israel (2000) involved hundreds of persons with severe neurologic d ... | 2003 | 19753724 |
| hepatitis g virus (hgv): current perspectives. | five viruses are usually associated with hepatitis in humans: a-e. in addition to these viruses as aetiological agents of hepatitis, there remain a number of patients with hepatitis in whom no virus could be identified. it was therefore postulated that there may be other agents which may be causing hepatitis. recently, two viruses have been associated with hepatitis: hepatitis g virus (hgv), and transfusion transmissible virus (ttv). hepatitis g virus (hgv) is a single stranded rna virus which r ... | 2002 | 12593580 |
| intrauterine west nile virus infection--new york, 2002. | west nile virus (wnv), a mosquito-borne flavivirus and human neuropathogen, is epidemic in the united states. in 2002, newly recognized mechanisms of person-to-person wnv transmission were described, including possible transmission from mother to infant through breast milk. wnv has not been previously associated with intrauterine infection or adverse birth outcomes. this report describes a case of transplacental wnv transmission. pregnant women should take precautions to reduce their risk for wn ... | 2002 | 12537289 |
| new inferences from tree shape: numbers of missing taxa and population growth rates. | the relative positions of branching events in a phylogeny contain information about evolutionary and population dynamic processes. we provide new summary statistics of branching event times and describe how these statistics can be used to infer rates of species diversification from interspecies trees or rates of population growth from intraspecies trees. we also introduce a phylogenetic method for estimating the level of taxon sampling in a clade. different evolutionary models and different samp ... | 2002 | 12554454 |
| laboratory-acquired west nile virus infections--united states, 2002. | west nile virus (wnv), a mosquito-borne flavivirus introduced recently to north america, is a human, equine, and avian neuropathogen. the majority of human infections with wnv are mosquito-borne; however, laboratory-acquired infections with wnv and other arboviruses also occur. this report summarizes two recent cases of wnv infection in laboratory workers without other known risk factors who acquired infection through percutaneous inoculation. laboratory workers handling fluids or tissues known ... | 2002 | 12537288 |
| sequence diversity of the capsid gene and the nonstructural gene ns2b of dengue-3 virus in vivo. | previously, we studied the envelope (e) gene of dengue virus and reported that dengue-3 virus is present as a quasispecies. to investigate the extent of intrahost sequence variation of other dengue viral genes, we examined in this study the capsid (c) gene and the nonstructural gene, ns2b, derived directly from plasma dengue viruses from 18 confirmed dengue-3 patients. using reverse transcription-pcr, multiple clones of a 360-nucleotide region covering the c gene and of a 404-nucleotide region c ... | 2002 | 12482670 |
| mycophenolic acid inhibits dengue virus infection by preventing replication of viral rna. | dengue fever is a mosquito-borne viral disease of global importance with no available antiviral therapy. we assessed the ability of mycophenolic acid (mpa), a drug currently used as an immunosuppressive agent, to inhibit dengue virus (dv) antigen expression, rna replication, and virus production. pharmacological concentrations of mpa effectively blocked dv infection, decreasing the percentage of infected cells by 99% and the levels of secreted virus by up to a millionfold. results were reproduce ... | 2002 | 12504563 |
| poly i:clc induction of the interferon system in mice: an initial study of four detection methods. | induction of a large number of the components of the interferon (ifn) system (ifn genes, their mrnas, ifn proteins, ifn receptors, ifn signaling molecules, the ifn response genes, and their effector proteins) has been studied. less well studied is the comparative induction of these components in vivo. induction of ifn by double-stranded rna (dsrna) treatment mimics certain aspects of viral infection and induces the components of the ifn system. to determine the comparative sensitivity of detecti ... | 2002 | 12433283 |
| reactivity of serum samples from patients with a flavivirus infection measured by immunofluorescence assay and elisa. | flavivirus infections are a significant public health problem, since several members of the flaviviridae family are highly pathogenic to humans. accurate diagnosis and differentiation of the infecting virus is important, especially in areas where many flaviviruses are circulating. in this study we evaluated a newly developed commercially available immunofluorescence assay (ifa) (indx, baltimore, md, usa) for the detection of igm and igg antibodies against dengue virus, yellow fever virus, japane ... | 2002 | 12467761 |
| the epidemiology of yellow fever in africa. | yellow fever (yf) is still a major public heath problem, particularly in africa, despite the availability of a very efficacious vaccine. the world health organization estimates that there are 200,000 cases of yf annually, including 30,000 deaths, of which over 90% occur in africa. in the past 15 years, the number of yf cases has increased tremendously, with most of the yf activity in west africa. this increase in yf activity is in part due to a breakdown in yf vaccination and mosquito control pr ... | 2002 | 12475636 |
| novelity in gb virus c/hepatitis g virus and its controversy. | several novel human rna viruses were identified in 1995-96 and were partially characterized that apparently can cause acute and chronic hepatitis both in monkeys and humans. these new viruses are related to the flavivirus hepatitis c. it is known to be distinct from other human hepatitis viruses (a, b, c, d, e). three viruses, identified by investigators at abbott labs, have been termed gb-a, gb-b and gb-c. gb-a and gb-b are likely tamarin viruses whereas gb-c infects humans only. all these thre ... | 2002 | 12476863 |
| requirements for de novo initiation of rna synthesis by recombinant flaviviral rna-dependent rna polymerases. | rna-dependent rna polymerases (rdrps) that initiate rna synthesis by a de novo mechanism should specifically recognize the template initiation nucleotide, t1, and the substrate initiation nucleotide, the ntpi. the rdrps from hepatitis c virus (hcv), bovine viral diarrhea virus (bvdv), and gb virus-b all can initiate rna synthesis by a de novo mechanism. we used rnas and gtp analogs, respectively, to examine the use of the t1 nucleotide and the initiation nucleotide (ntpi) during de novo initiati ... | 2002 | 12438578 |
| effect of triethylamine on the recovery of selected south american alphaviruses, flaviviruses, and bunyaviruses from mosquito (diptera: culicidae) pools. | we evaluated the effect of triethylamine (tea) on the recovery of infectious virus from pools of mosquitoes for two south american alphaviruses (eastern equine encephalomyelitis and venezuelan equine encephalomyelitis subtypes iiic and id), one flavivirus (ilheus) and two bunyaviruses (mirim [guama group] and itaqui [group c]). mosquitoes were inoculated intrathoracically with virus, held for 7-10 d at 26 degrees c, and handled under one of four regimens before testing for the presence of virus ... | 2002 | 12349865 |
| complementation analysis of the flavivirus kunjin ns3 and ns5 proteins defines the minimal regions essential for formation of a replication complex and shows a requirement of ns3 in cis for virus assembly. | we have previously reported successful trans-complementation of defective kunjin virus genomic rnas with a range of large lethal deletions in the nonstructural genes ns1, ns3, and ns5 (a. a. khromykh et al., j. virol. 74:3253-3263, 2000). in this study we have mapped further the minimal region in the ns5 gene essential for efficient trans-complementation of genome-length rnas in repbhk cells to the first 316 of the 905 codons. to allow amplification and easy detection of complemented defective r ... | 2002 | 12368319 |
| epizootic activity of murray valley encephalitis virus in an aboriginal community in the southeast kimberley region of western australia: results of cross-sectional and longitudinal serologic studies. | murray valley encephalitis (mve) virus is a mosquito-borne flavivirus causing severe encephalitis with a resultant high morbidity and mortality. in the period 1989-1993, we undertook a cross-sectional and longitudinal study by annually screening members of a small remote aboriginal community in northwestern australia for mve virus antibodies. of the estimated 250-300 people in the community, 249 were tested, and 52.6% had positive serology to mve. the proportion testing positive increased with i ... | 2002 | 12408675 |
| characterization and e protein expression of mutant strains during persistent infection of kn73 cells with japanese encephalitis virus. | to study the character of mutants originating from japanese encephalitis viruses and the relationship between the characterization of mutant strains and e protein expression. | 2002 | 12411104 |
| sentinel chicken surveillance programme in australia, 1 july 2001 to 30 june 2002. | detection of flavivirus seroconversions in sentinel chicken flocks located throughout australia is used to provide an early warning of increased levels of murray valley encephalitis (mve) and kunjin virus activity in the region. during the 2001/2002 season low levels of flavivirus activity were detected in northern australia compared to previous years. mve and kunjin virus activity was detected in the kimberley and pilbara regions of western australia and the northern territory but not in north ... | 2002 | 12416705 |
| classical swine fever virus ns5b-gfp fusion protein possesses an rna-dependent rna polymerase activity. | rna-dependent rna polymerase (rdrp) is the replicase of positive-strand rna viruses. expression and characterization of the replicase are the first steps in the elucidation of the virus replication mechanism. we expressed nonstructural protein 5b (ns5b) of classical swine fever virus (csfv) as a fusion protein with green fluorescent protein (gfp) in porcine kidney cells (pk-15 cells), natural host cells of csfv. the expressed csfv ns5b-gfp fusion protein possessed rdrp activity. by fluorescence ... | 2002 | 12209316 |
| infection of polarized epithelial cells with flavivirus west nile: polarized entry and egress of virus occur through the apical surface. | both polarized epithelial vero (c1008) and non-polarized vero (control) cells were grown on permeable cell culture inserts and infected either apically or basolaterally with west nile (wn) or kunjin (kun) virus. kun virus (closely related to wn virus) was used as a comparison. using indirect immunofluorescence and plaque assays of productive virus titres, entry of wn and kun viruses was confined to the apical surface of polarized epithelial cells. for the first time, these results provided evide ... | 2002 | 12237424 |
| clinical proof of principle for chimerivax: recombinant live, attenuated vaccines against flavivirus infections. | chimerivax is a live, attenuated recombinant virus constructed from yellow fever (yf) 17d in which the envelope protein genes of yf 17d are replaced with the corresponding genes of another flavivirus. a chimerivax vaccine was developed against japanese encephalitis (je). a randomized, double-blind, outpatient study was conducted to compare the safety and immunogenicity of chimerivax-je and yf 17d. six yf immune and six non-immune adults were randomized to receive a single sc inoculation of chime ... | 2002 | 11803060 |
| modes of transmission of hemorrhagic fever. | 2002 | 12150658 | |
| a nonsense mutation in the gene encoding 2'-5'-oligoadenylate synthetase/l1 isoform is associated with west nile virus susceptibility in laboratory mice. | a mouse model has been established to investigate the genetic determinism of host susceptibility to west nile (wn) virus, a member of the genus flavivirus and family flaviviridae. whereas wn virus causes encephalitis and death in most laboratory inbred mouse strains after peripheral inoculation, most strains derived from recently trapped wild mice are completely resistant. the phenotype of resistance/susceptibility is determined by a major locus, wnv, mapping to chromosome 5 within the 0.4-cm-wi ... | 2002 | 12186974 |
| west nile virus. | west nile (wn) virus is a mosquito-borne flavivirus and human, equine, and avian neuropathogen. the virus is indigenous to africa, asia, europe, and australia, and has recently caused large epidemics in romania, russia, and israel. birds are the natural reservoir (amplifying) hosts, and wn virus is maintained in nature in a mosquito-bird-mosquito transmission cycle primarily involving culex sp mosquitoes. wn virus was recently introduced to north america, where it was first detected in 1999 duri ... | 2002 | 12206968 |
| complete genome sequence of montana myotis leukoencephalitis virus, phylogenetic analysis and comparative study of the 3' untranslated region of flaviviruses with no known vector. | montana myotis leukoencephalitis virus (mmlv), a virus isolated from bats, causes an encephalitis in small rodents reminiscent of flavivirus encephalitis in humans. the complete mmlv genome is 10690 nucleotides long and encodes a putative polyprotein of 3374 amino acids. the virus contains the same conserved motifs in genes that are believed to be interesting antiviral targets (ntpase/helicase, serine protease and rna-dependent rna polymerase) as flaviviruses of clinical importance. phylogenetic ... | 2002 | 12124451 |
| infection of scid mice with montana myotis leukoencephalitis virus as a model for flavivirus encephalitis. | we have established a convenient animal model for flavivirus encephalitis using montana myotis leukoencephalitis virus (mmlv), a bat flavivirus. this virus has the same genomic organization, and contains the same conserved motifs in genes that encode potential antiviral targets, as flaviviruses that cause disease in man (n. charlier et al., accompanying paper), and has a similar particle size (approximately 40 nm). mmlv replicates well in vero cells and appears to be equally as sensitive as yell ... | 2002 | 12124452 |
| seasonal abundance of culex nigripalpus theobald and culex salinarius coquillett in north florida, usa. | north florida is a transition zone between widespread culex nigripalpus populations to the south and focal culex salinarius populations to the north. culex nigripalpus is a vector of st. louis encephalitis (sle) and eastern equine encephalitis (eee) viruses in south florida, while cx. salinarius is a suspected new world vector of west nile (wn) virus. abundant vector populations are often a prerequisite for epidemic and epizootic transmission of arboviruses. extensive sle transmission has never ... | 2002 | 12125867 |
| safety and immunogenicity of tetravalent live-attenuated dengue vaccines in thai adult volunteers: role of serotype concentration, ratio, and multiple doses. | dengue fever, caused by four serotypes of a mosquito-borne virus, is a growing problem in tropical countries. currently, there is no treatment or vaccine. we evaluated safety and immunogenicity of two doses, given six months apart, of seven formulations of dengue tetravalent live-attenuated vaccine (containing different concentrations of the component viruses) versus placebo in 59 flavivirus-seronegative thai adults. the first dose was the more reactogenic. most volunteers experienced clinically ... | 2002 | 12139219 |
| tick-borne encephalitis (tbe) in dogs. | tick-borne encephalitis (tbe) is caused by a flavivirus and transmitted by ticks. it is known in dogs for nearly 30 years and the number of tbe cases is increasing. in addition to fever, cerebrocortical, thalamic, and brainstem symptoms occur simultaneously. not all tbe infections in dogs lead to clinical signs but peracute/lethal as well as subacute and chronic courses have been reported. tbe is a seasonal disease, depending on climate related tick activity. infected ticks are spreading the vir ... | 2002 | 12141763 |
| reappearance of human cases due to murray valley encephalitis virus and kunjin virus in central australia after an absence of 26 years. | murray valley encephalitis (mve) and kunjin virus disease are endemic in the tropical parts of the northern territory and western australia, but have been absent from central australia since 1974. in 2000, 5 laboratory-confirmed cases of encephalitis occurred over a short period in the normally dry inland region of central australia. the sudden occurrence of cases in march and april 2000 followed unusually high rainfall in the preceding months and evidence of flavivirus activity in the endemic a ... | 2002 | 11950201 |
| antibodies against prm protein distinguish between previous infection with dengue and japanese encephalitis viruses. | in southeast asia, dengue viruses often co-circulate with other flaviviruses such as japanese encephalitis virus, and due to the presence of shared antigenic epitopes it is often difficult to use serological methods to distinguish between previous infections by these flaviviruses. | 2002 | 12019028 |
| the molecular biology of west nile virus: a new invader of the western hemisphere. | west nile virus (wnv) is a mosquito-borne flavivirus that primarily infects birds but occasionally also infects humans and horses. in recent years, the frequency of wnv outbreaks in humans has increased, and these outbreaks have been associated with a higher incidence of severe disease. in 1999, the geographical distribution of wnv expanded to the western hemisphere. wnv has a positive strand rna genome of about 11 kb that encodes a single polyprotein. wnv replicates in the cytoplasm of infected ... | 2002 | 12142476 |
| t cell responses to an hla-b*07-restricted epitope on the dengue ns3 protein correlate with disease severity. | dengue hemorrhagic fever (dhf), the severe manifestation of dengue virus (dv) infection characterized by plasma leakage, is more common in secondary dv infections in previously infected individuals and is associated with high levels of immune activation. to determine the ag specificity of this immune response, we studied the response to an hla-b*07-restricted t cell epitope, residues 221-232 of the dv ns3 protein, in 10 hla-b*07(+) thai children who were studied during and after acute dv infecti ... | 2002 | 12023403 |
| expression, purification, and characterization of the rna 5'-triphosphatase activity of dengue virus type 2 nonstructural protein 3. | dengue virus type 2 (den2), a member of the flaviviridae family of positive-strand rna viruses, contains a single rna genome having a type i cap structure at the 5' end. the viral rna is translated to produce a single polyprotein precursor that is processed to yield three virion proteins and at least seven nonstructural proteins (ns) in the infected host. ns3 is a multifunctional protein having a serine protease catalytic triad within the n-terminal 180 amino acid residues which requires ns2b as ... | 2002 | 12167347 |
| fatal yellow fever in a traveler returning from amazonas, brazil, 2002. | 2002 | 12025823 | |
| an rna cap (nucleoside-2'-o-)-methyltransferase in the flavivirus rna polymerase ns5: crystal structure and functional characterization. | viruses represent an attractive system with which to study the molecular basis of mrna capping and its relation to the rna transcription machinery. the rna-dependent rna polymerase ns5 of flaviviruses presents a characteristic motif of s-adenosyl-l-methionine-dependent methyltransferases at its n-terminus, and polymerase motifs at its c-terminus. the crystal structure of an n-terminal fragment of dengue virus type 2 ns5 is reported at 2.4 a resolution. we show that this ns5 domain includes a typ ... | 2002 | 12032088 |
| mouse neuroinvasive phenotype of west nile virus strains varies depending upon virus genotype. | despite recent advances in the genetics of west nile (wn) virus, relatively little is known about the molecular basis of virulence of this virus. in particular, although the genotype of the wn virus strain that was recently introduced into north america has been determined, there have been few experimental studies on the virulence phenotype of the virus. we compared genetic and neurovirulence properties of 19 strains of wn virus, including 2 from north america, and observed significant differenc ... | 2002 | 12036314 |
| flavivirus susceptibility in aedes aegypti. | aedes aegypti is the primary vector of yellow fever (yf) and dengue fever (df) flaviviruses worldwide. in this review we focus on past and present research on genetic components and environmental factors in aedes aegypti that appear to control flavivirus transmission. we review genetic relationships among ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. we describe current research into h ... | 2002 | 12234528 |
| [localization of tick-borne encephalitis virus protein e antigenic determinant recognized by antihemagglutinating monoclonal antibodies using a phage-display peptide library]. | bacteriophages bearing peptides reacting with antihemagglutinating monoclonal antibodies (mab) 10h10 to tick-borne encephalitis (tbe) virus protein e were selected from a phage-display peptide library by affinity selection and enzyme immunoassay. the library contained randomized peptides that are 6 amino acids long, fused with protein piii and exposed on the surface of the bacteriophage. no significant homology between the sequences of selected peptides and tbe virus protein e was detected. comp ... | 2002 | 12046465 |
| genome sequence analysis of tamana bat virus and its relationship with the genus flavivirus. | tamana bat virus (tabv, isolated from the bat pteronotus parnellii) is currently classified as a tentative species in the genus flavivirus: we report here the determination and analysis of its complete coding sequence. low but significant similarity scores between tabv and member-viruses of the genus flavivirus were identified in the amino acid sequences of the structural, ns3 and ns5 genes. a series of cysteines located in the envelope protein and the most important enzymatic domains of the vir ... | 2002 | 12237426 |
| in vitro determination of dengue virus type 2 ns2b-ns3 protease activity with fluorescent peptide substrates. | the ns2b-ns3(pro) polyprotein segment from the dengue virus serotype 2 strain 16681 was purified from overexpressing e. coli by metal chelate affinity chromatography and gel filtration. enzymatic activity of the refolded ns2b-ns3(pro) protease complex was determined in vitro with dansyl-labeled peptide substrates, based upon native dengue virus type 2 cleavage sites. the 12mer substrate peptides and the cleavage products could be separated by reversed-phase hplc, and were identified by uv and fl ... | 2002 | 12297031 |
| emerging arboviral diseases. | 2002 | 12054284 | |
| ns3 protease of langat tick-borne flavivirus cleaves serine protease substrates. | langat (lgt) virus, initially isolated in 1956 from ticks in malaysia, is a naturally occurring nonpathogenic virus with a very close antigenicity to the highly pathogenic tick-borne encephalitis (tbe) western subtype virus and tbe far eastern subtype virus. ns3, the second largest viral protein of lgt virus, is highly conserved among flaviviruses and contains a characteristic protease moiety (ns3 pro). ns3 pro represents an attractive target for anti-protease molecules against tbe virus. we rep ... | 2002 | 12054734 |
| clinical and immunological risk factors for severe disease in japanese encephalitis. | eighty-five paediatric patients in thailand with acute japanese encephalitis (je) were studied in 1987-99 to determine risk factors present at hospital admission which were associated with severe disease. on univariate analysis, the following factors on admission were significantly associated with the combined end-point of death or a severe neurological deficit: depressed level of consciousness, elevated concentration of cerebrospinal fluid (csf) protein, low levels of serum and csf igg antibody ... | 2002 | 12055808 |