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clinical utility of commercial enzyme immunoassays during the inaugural season of west nile virus activity, alberta, canada.west nile virus (wnv) has spread rapidly across north america, creating a need for rapid and accurate laboratory diagnosis on a large scale. immunoglobulin m (igm) capture enzyme immunoassays (eia) became commercially available in the summer of 2003, but limited data are available on their clinical performance. consolidated human wnv diagnostic testing for the province of alberta, canada, at the public health laboratory permitted a large-scale evaluation of the assays, covering a wide clinical s ...200516145128
critical roles for both stat1-dependent and stat1-independent pathways in the control of primary dengue virus infection in mice.dengue virus (den), a flavivirus, causes dengue fever and dengue hemorrhagic fever/dengue shock syndrome, the most common mosquito-borne viral illnesses in humans worldwide. in this study, using stat1(-/-) mice bearing two different mutant stat1 alleles in the 129/sv/ev background, we demonstrate that ifnr-dependent control of primary den infection involves both stat1-dependent and stat1-independent mechanisms. the stat1 pathway is necessary for clearing the initial viral load, whereas the stat1 ...200516148142
new developments in flavivirus vaccines with special attention to yellow fever.here we review recent epidemiological trends in flavivirus diseases, findings related to existing vaccines, and new directions in flavivirus vaccine research. we emphasize the need for stepped-up efforts to stop further spread and intensification of these infections worldwide.200516148524
immune responses to non-structural protein 3 (ns3) of bovine viral diarrhoea virus (bvdv) in ns3 dna vaccinated and naturally infected cattle.immune responses to non-structural protein 3 (ns3) of bovine viral diarrhoea virus (bvdv) were investigated. cdna encoding ns3 from type 1a bvdv was used to vaccinate five calves, another five calves remained unvaccinated. three weeks after final vaccination animals were challenged intranasally with heterologous type 1a bvdv. anti-ns3 antibodies were detected in only one animal post-vaccination. partial protection from virus challenge was observed in the vaccinates. virus was not isolated from n ...200516169103
experimental transmission of west nile virus (flaviviridae: flavivirus) by carios capensis ticks from north america.seabird soft ticks, carios capensis (ixodida: argasidae), originally collected from coastal georgia, usa, were allowed to ingest a blood meal from pekin ducklings (anas domesticus) infected with wnv. after 35 days of extrinsic incubation, the ticks transmitted virus to naive ducklings. wnv was detected via plaque assay and rtpcr in ticks and in tissues and serum of ducklings 7 days post infestation.200516187900
inhibition of interferon-stimulated jak-stat signaling by a tick-borne flavivirus and identification of ns5 as an interferon antagonist.the tick-borne encephalitis (tbe) complex of viruses, genus flavivirus, can cause severe encephalitis, meningitis, and/or hemorrhagic fevers. effective interferon (ifn) responses are critical to recovery from infection with flaviviruses, and the mosquito-borne flaviviruses can inhibit this response. however, little is known about interactions between ifn signaling and tbe viruses. langat virus (lgtv), a member of the tbe complex of viruses, was found to be highly sensitive to the antiviral effec ...200516188985
[flavivirus encephalitis: focus on west nile encephalitis].the genus flavivirus, family flaviviridae includes a serocomplex of vector-borne neurotropic viruses as in the tick-borne encephalitis virus serocomplex and the japanese encephalitis virus serocomplex. the tick-borne encephalitis virus serocomplex includes central european encephalitis virus and russian spring summer encephalitis virus. west nile virus (wnv), which in the western hemisphere was first detected in new york, in the united states in 1999, is one of several mosquito-borne members of ...200516190358
gb virus-c--a virus without a disease: we cannot give it chronic fatigue syndrome.chronic fatigue syndrome (cfs) is an illness in search of an infectious etiology. gb virus-c (gbv-c) virus is a flavivirus with cell tropism and host defense induction qualities compatible with a role in producing the syndrome. the gbv-c genome is detectable in 4% of the population and 12% of the population is seropositive. the present study evaluated the association between infection with gbv and cfs.200516191201
proteomic profiling and neurodegeneration in west-nile-virus-infected neurons.west nile virus, a mosquito-borne flavivirus, is a human, equine, and avian pathogen. high-resolution two-dimensional differential-gel electrophoresis (2d-dige) was used to characterize protein expression in primary rat neurons and to examine the proteomic profiling to understand the pathogenesis of west-nile-associated meningoencephalitis. three ph ranges, 3-10, 4-7, and 5-6, were used to analyze the protein spots. the proteins are labeled with fluorescent dyes cy3 and cy5 before being separate ...200516192685
structural basis of west nile virus neutralization by a therapeutic antibody.west nile virus is a mosquito-borne flavivirus closely related to the human epidemic-causing dengue, yellow fever and japanese encephalitis viruses. in establishing infection these icosahedral viruses undergo endosomal membrane fusion catalysed by envelope glycoprotein rearrangement of the putative receptor-binding domain iii (diii) and exposure of the hydrophobic fusion loop. humoral immunity has an essential protective function early in the course of west nile virus infection. here, we investi ...200516193056
[molecular characteristics of three new isolates of japanese encephalitis virus in fujian province].to analyze the genotype of newly isolated japanese encephalitis viruses in fujian province and the characteristics of amino acid sequence in the e gene.200516201460
serotype-specific detection of dengue viruses in a fourplex real-time reverse transcriptase pcr assay.the dengue (den) viruses are positive-strand rna viruses in the genus flavivirus. dengue fever and dengue hemorrhagic fever/dengue shock syndrome are important human arboviral diseases caused by infection with one of four closely related but serologically distinct den viruses, designated den-1, den-2, den-3, and den-4 viruses. all four den serotypes are currently co-circulating throughout the subtropics and tropics, and genotypic variation occurs among isolates within a serotype. a real-time qua ...200516207951
domain iii from class ii fusion proteins functions as a dominant-negative inhibitor of virus membrane fusion.alphaviruses and flaviviruses infect cells through low ph-dependent membrane fusion reactions mediated by their structurally similar viral fusion proteins. during fusion, these class ii viral fusion proteins trimerize and refold to form hairpin-like structures, with the domain iii and stem regions folded back toward the target membrane-inserted fusion peptides. we demonstrate that exogenous domain iii can function as a dominant-negative inhibitor of alphavirus and flavivirus membrane fusion and ...200516216925
molecular epidemiology of dengue 2 viruses in the philippines: genotype shift and local evolution.the pre-membrane (prm) and envelope (e) genes of 41 viruses isolated from dengue fever (df), dengue hemorrhagic fever (dhf), and dengue shock syndrome (dss) patients from 1995 to 2002 were sequenced to determine the genetic variability of dengue 2 (denv 2) viruses in the philippines. the envelope sequence data were compared with a global sample of denv 2 obtained from genbank. phylogenetic analysis revealed that two distinct genotypes, asian 2 and cosmopolitan, are currently circulating locally, ...200516222028
nucleotide and amino acid changes in west nile virus strains exhibiting renal tropism in hamsters.recent studies have shown that west nile virus (wnv) can induce an asymptomatic persistent infection in the kidneys of experimentally infected hamsters. the chronically infected rodents shed virus in their urine for up to 8 months, despite the disappearance of viremia and the development of high levels of neutralizing antibodies. wnv, like most members of the japanese encephalitis virus complex (flavivirus; flaviviridae), is assumed to be mainly neurotropic; little is known about the genetic bas ...200516222029
shifting epidemiology of flaviviridae.the dengue, west nile, japanese encephalitis and yellow fever viruses are important mosquito-borne viruses whose epidemiology is shifting in response to changing societal factors, such as increasing commerce, urbanization of rural areas, and population growth. all four viruses are expanding geographically, as exemplified by the emergence of west nile virus in the americas and japanese encephalitis virus in australasia. the large, recent global outbreaks of severe neurological disease caused by w ...200516225801
hantavirus gc glycoprotein: evidence for a class ii fusion protein.hantavirus cell entry is promoted by its envelope glycoproteins, gn and gc, through cell attachment and by fusion between viral and endosomal membranes at low ph. however, the role of gn and gc in receptor binding and cell fusion has not yet been defined. in this work, a sequence presenting characteristics similar to those of class ii fusion peptides (fps) of alphavirus e1 and flavivirus e proteins is identified within the hantavirus gc glycoprotein. a three-dimensional comparative molecular mod ...200516227214
n-linked glycosylation of west nile virus envelope proteins influences particle assembly and infectivity.west nile virus (wnv) encodes two envelope proteins, premembrane (prm) and envelope (e). while the prm protein of all wnv strains contains a single n-linked glycosylation site, not all strains contain an n-linked site in the e protein. the presence of n-linked glycosylation on flavivirus e proteins has been linked to virus production, ph sensitivity, and neuroinvasiveness. therefore, we examined the impact of prm and e glycosylation on wnv assembly and infectivity. similar to other flaviviruses, ...200516227249
alpha/beta interferon protects against lethal west nile virus infection by restricting cellular tropism and enhancing neuronal survival.west nile virus (wnv) is a mosquito-borne flavivirus that is neurotropic in humans, birds, and other animals. while adaptive immunity plays an important role in preventing wnv spread to the central nervous system (cns), little is known about how alpha/beta interferon (ifn-alpha/beta) protects against peripheral and cns infection. in this study, we examine the virulence and tropism of wnv in ifn-alpha/beta receptor-deficient (ifn- alpha/betar-/-) mice and primary neuronal cultures. ifn-alpha/beta ...200516227257
hippocampal involvement in dengue fever.flaviviruses are among the most important emerging viruses known to man. dengue is the most common flavivirus infection in singapore, and is transmitted between humans by the aedes mosquito. we report a 25-year-old man with dengue fever complicated by selective hippocampal involvement manifesting as amnesia. this has not been described in the literature previously. dengue polymerase chain reaction and serology were positive. magnetic resonance imaging of the brain showed bilateral hippocampal in ...200516228099
west nile virus antibodies in colombian horses. 200516673523
[viral fusion mechanisms].the majority of viral fusion proteins can be divided into two classes. the influenza hemagglutinin (ha) belongs to the class i fusion proteins and undergoes a series of conformational changes at acidic ph, leading to membrane fusion. the crystal structures of the prefusion and the postfusion forms of ha have been revealed in 1981 and 1994, respectively. on the basis of these structures, a model for the mechanism of membrane fusion mediated by the conformational changes of ha has been proposed. t ...200516557006
[isolation and identification of arboviruses from mosquito pools in yunnan province].to survey arboviruses in yunnan province.200516415987
[molecular biological survey of tick-born arboviruses in southern part of xinjiang].to disclose the species and distribution of tick-borne arboviruses in the southern part of xinjiang.200516415988
[expression of tick-borne encephalitis virus prm-e protein in insect cells and studies on its antigenicity].to express the prm-e protein in sf9 cells, and lay a basis for further study on the function of the viral proteins and development of specific diagnostic reagents.200516415990
[comparison and discrimination of the biological characteristics between west nile virus and japanese encephalitis virus].to compare the biological characteristics of west nile virus (wnv) and japanese encephalitis virus (jev), including cells sensitivity, pathogenicity, viral morphology, as well as the results of immunological and molecular biological detection.200516415991
west nile virus in southern portugal, 2004.west nile virus (wnv) genomic rna was detected by reverse transcription-polymerase chain reaction (rt-pcr) in six out of 57 mosquito pools collected in southern portugal, during the summer of 2004, yielding an infection rate (ir) of 2.8/1,000 mosquitoes. phylogenetic analysis of a 217-nucleotide fragment of the ns5 coding region, amplified from culex pipiens s.l. and culex univittatus unfed females, demonstrated a close relationship with wnv strains circulating in the mediterranean basin (italy, ...200516417437
assessing the genetic component of the susceptibility of mice to viral infections.laboratory mice often exhibit wide differences in susceptibility when infected experimentally with viruses. based on such observations, experiments have been designed to investigate the determinism of these differences at the molecular level, and a few genes that play a major role in the innate mechanisms of defence of the species toward viral aggressions have been characterised. for example, the extraordinary resistance of sjl mice to experimental infections with hepatitis virus strain a59 is t ...200516420748
[west nile fever and west nile encephalitis].west nile virus is a mosquito-borne flavivirus, and maintained in mosquito-bird cycle in nature. humans are a dead-end host in west nile virus infection. symptoms are developed in approximately 20% of west nile virus-infected humans. encephalitis and meningitis are developed in about 1 out of 150 infected humans, especially in elderly populations. it has recently been reported that west nile virus causes polio-like, acute flaccid paralysis and polyneuritis. these symptoms occur in patients witho ...200516447753
serologic survey of select infectious diseases in coyotes and raccoons in nebraska.to obtain data about select zoonotic and other infectious diseases in free-ranging predators in five ecoregions in nebraska, sera were collected from 67 coyotes (canis latrans) and 63 raccoons (procyon lotor) from november 2002 through january 2003. for coyotes, antibodies were detected against canine distemper virus (cdv, 61%), francisella tularensis (32%), rickettsia rickettsi (13%), and flaviviruses (48%). none of the coyote sera had antibodies to borrelia burgdorferi, brucella canis, or six ...200516456169
sentinel pigeon surveillance for west nile virus by using lard-can traps at differing elevations and canopy cover classes.sentinel pigeons, columba livia, were installed in lard-can traps at heights of 1.5 m and 7.6-9.1 m within differing canopy cover classes in new york city. adult mosquitoes were collected weekly from july to october 2002, as were serum samples from each pigeon. culex pipiens l. and culex restuans theobald comprised 97% of mosquitoes collected and were most numerous in canopy-level, forested traps. the west nile virus (family flaviviridae, genus flavivirus, wnv) seroconversion rate was significan ...200516465746
monitoring of japanese encephalitis virus infection in mosquitoes (diptera: culicidae) at guandu nature park, taipei, 2002-2004.japanese encephalitis virus (jev) infection in mosquitoes was monitored at guandu nature park in taipei city from september 2002 to december 2004. in total, 30,386 female mosquitoes consisting of six genera and 14 species were processed for virus in 1,229 pools by using flavivirus ns5 gene sequences detected by reverse transcription-polymerase chain reaction (pcr) and nested pcr assay. overall, 101 pools were positive, including 95, 1, 4, and 1 for culex tritaeniorhynchus giles, culex sitiens wi ...200516465752
rapid identification of dengue virus by reverse transcription-polymerase chain reaction using field-deployable instrumentation.dengue virus universal and dengue serotype 1 to 4, fluorogenic probe hydrolysis (taqman), reverse transcription-polymerase chain reaction assays were developed for screening and serotype identification of infected mosquito vectors and human sera using a field-deployable, fluorometric thermocycler. dengue universal and dengue 1 to 4 serotype assay in vitro sensitivity and specificity results were 100% concordant when tested with total nucleic acid extracts of multiple strains of dengue serotype 1 ...200516491947
a clinico epidemiological study on acute viral infection of brain among children admitted in north bengal medical college, west bengal.a clinico epidemiological prospective study was carried out on acute viral infection of brain among children admitted in a rural based medical college from september '99 to oct '01. out of 80 cases, 8 cases (10%) of aseptic meningitis, 35 cases (43.75%) of encephalitis and 37 cases (6.25%) of meningo-encephalitis were found. overall case fatality was 47.5% and found higher (77%) among normally nourished children in comparison to malnourished children (47.5%). virological investigation did not is ...200516479917
concentration of procalcitonin and c-reactive protein in patients with human granulocytic anaplasmosis and the initial phase of tick-borne encephalitis.the aim of this prospective study was to assess the value of procalcitonin (pct) level and serum concentration of c-reactive protein (crp) in differentiating viral from bacterial infection in selected groups of patients, including those with acute human granulocytic anaplasmosis (hga), which is caused by an intracellular bacteria anaplasma phagocytophilum, and patients with the initial phase of tick-borne encephalitis (tbe), which is a viral disease caused by an rna virus belonging to the flaviv ...200516481557
inhibitory effect of rnai on japanese encephalitis virus replication in vitro and in vivo.flaviviruses include many insect-mediated small viruses and still cause serious problems in the world. in humans, jev can cause acute meningioencephalomyelitis, resulting in fatality rates of 5 to 40%. rna-interference (rnai) as an antiviral mechanism was originally discovered in plants and then found in the specific suppression of gene expression of other organisms such as caenorhabditis elegans, drosophila and vertebrates. as jev is an rna virus, rnai could be a reasonable approach for therape ...200516365529
isolation of viruses from mosquitoes (diptera: culicidae) collected in the amazon basin region of peru.as part of a comprehensive study on the ecology of arthropod-borne viruses in the amazon basin region of peru, we assayed 539,694 mosquitoes captured in loreto department, peru, for arboviruses. mosquitoes were captured either by dry ice-baited miniature light traps or with aspirators while mosquitoes were landing on human collectors, identified to species, and later tested on vero cells for virus. in total, 164 virus isolations were made and included members of the alphavirus (eastern equine en ...200516366001
[japanese encephalitis].japanese encephalitis is an arboviral disease due to a flavivirus transmitted by a mosquito of the genus culex. it is a major public health problem in southeast asia where it is endemo-epidemic. the socio-economic impact of japanese encephalitis is great since most cases occur in children and young adults and lead to death in 25 to 30 % and neurological sequelae in survivors. the tendency of japanese encephalitis to spread geographically and the existence of imported cases are particularly impor ...200516548493
dengue vaccine.dengue is an expanding health problem. about two-fifths of the world population are at risk for acquiring dengue with 50-100 million cases of acute febrile illness yearly including about 500,000 cases of dhf/dss. no antiviral drugs active against the flavivirus exist. attempts to control mosquito vector has been largely unsuccessful. vaccination remains the most hopeful preventive measure. dengue vaccine has been in development for more than 30 years, yet none has been licensed. the fact that en ...200516858980
cutaneous delivery of a live, attenuated chimeric flavivirus vaccine against japanese encephalitis (chimerivax)-je) in non-human primates.flaviviral diseases such as yellow fever, japanese encephalitis (je) and dengue hemorrhagic fever cause enormous morbidity and mortality worldwide. there is an urgent need for alternative technologies for mass vaccination against these and other diseases, particularly in the developing world. here, we administered a live attenuated, chimeric je vaccine (chimerivax)-je) to nonhuman primates by skin microabrasion and intradermal delivery using microneedles. both cutaneous delivery methods induced ...200517012854
the four serotypes of dengue recognize the same putative receptors in aedes aegypti midgut and ae. albopictus cells.dengue viruses (denv) attach to the host cell surface and subsequently enter the cell by receptor-mediated endocytosis. several primary and low affinity co-receptors for this flavivirus have been identified. however, the presence of these binding molecules on the cell surface does not necessarily render the cell susceptible to infection. determination of which of them serve as bona fide receptors for this virus in the vector may be relevant to treating denv infection and in designing control str ...200617014723
recent emergence of insensitive acetylcholinesterase in chinese populations of the mosquito culex pipiens (diptera: culicidae).organophosphate/carbamate target resistance has emerged in culex pipiens l. (diptera: culicidae), the vector of wuchereria bancrofti and west nile virus (family flaviviridae, genus flavivirus) in china. the insensitive acetylcholinesterase was detected in only one of 20 samples collected on a north-to-south transect. according to previous findings, a unique mutation, g119s in the ace-1 gene, explained this high insensitivity. phylogenetic analysis indicates that the mutation g119s recently detec ...200617017223
horse-, bird-, and human-seeking behavior and seasonal abundance of mosquitoes in a west nile virus focus of southern france.after 35 yr of disease absence, west nile virus (family flaviviridae, genus flavivirus, wnv) circulation has been regularly detected in the camargue region (southern france) since 2000. wnv was isolated from culex modestus ficalbi, which was considered the main vector in southern france after horse outbreaks in the 1960s. recent wnv transmissions outside of the cx. modestus distribution suggested the existence of other vectors. to study potential wnv vectors, horse- and bird-baited traps and hum ...200617017231
the potential of aedes triseriatus (diptera: culicidae) as an enzootic vector of west nile virus.the susceptibility of aedes triseriatus (say) (diptera: culicidae) to low levels of west nile virus (family flaviviridae, genus flavivirus, wnv) was determined and compared with that of culex pipiens l. to assess the likelihood of its participation in an enzootic cycle involving mammals. ae. triseriatus and cx. pipiens were exposed to wnv by feeding on baby chickens with wnv serum titers ranging from 10(4.1 +/- 0.1) to 10(8.6 +/- 0.1) plaque-forming units (pfu)/ml and from 10(4.1 +/- 0.1) to 10( ...200617017235
detection of west nile virus rna in pools of three species of ceratopogonids (diptera: ceratopogonidae) collected in louisiana.light traps were used to collect ceratopogonids in east baton rouge parish, louisiana. in total, 46,496 ceratopogonids were sorted from 4,968 light trap collections from 20 november 2002 through 25 november 2004. two hundred and nine pools containing specimens of 18 species of culicoides latreille, seven pools containing specimens of atrichopogon kieffer, and five pools containing specimens of forcipomyia meigen were tested for west nile virus (family flaviviridae, genus flavivirus, wnv) rna usi ...200617017242
laboratory transmission of japanese encephalitis, west nile, and getah viruses by mosquitoes (diptera: culicidae) collected near camp greaves, gyeonggi province, republic of korea 2003.we conducted experimental studies to evaluate mosquitoes captured in paju county, gyeonggi province, republic of korea, for their ability to transmit west nile virus (family flaviviridae, genus flavivirus, wnv), japanese encephalitis virus (family flaviviridae, genus flavivirus, jev), and getah virus (family togaviridae, genus alphavirus, getv) under laboratory conditions. both culex pipiens pallens coquillett and culex tritaeniorhynchus giles were highly susceptible to infection with wnv, with ...200617017248
identification of avian- and mammalian-derived bloodmeals in aedes vexans and culiseta melanura (diptera: culicidae) and its implication for west nile virus transmission in connecticut, u.s.a.to evaluate the host-feeding patterns of aedes vexans (meigen) and culiseta melanura (coquillett) as secondary vectors of west nile virus (family flaviviridae, genus flavivirus, wnv) in northeastern united states, we identified the source of vertebrate bloodmeals by sequencing portions of the cytochrome b gene of mitochondrial dna. analysis of polymerase chain reaction products from a total of 119 ae. vexans revealed that 92.4% of individuals acquired blood solely from mammalian and 2.5% from av ...200617017250
chimeric japanese encephalitis virus/dengue 2 virus infectious clone: biological properties, immunogenicity and protection against dengue encephalitis in mice.a molecular clone of japanese encephalitis virus (je virus) was derived from the je virus nakayama strain and used to produce infectious je virus in cell culture. the engineered je virus resembled the parental je virus in cell-culture properties and was related closely to other je virus strains based on nucleotide sequence analysis. the je virus clone was used as a genetic background for construction of a chimeric virus containing the structural proteins prm and e of dengue virus, serotype 2. th ...200617030845
ngoye virus: a novel evolutionary lineage within the genus flavivirus.by using degenerate primers deduced from conserved patterns in the flavivirus polymerase gene, a novel rna virus was discovered in rhipicephalus ticks sampled from members of the family bovidae in senegal. it was named ngoye virus (ngov) after the location from which it was isolated. viral particles could be observed by electron microscopy, but isolation in vertebrate or invertebrate cell lines or by intracerebral infection of newborn mice remained unsuccessful. this is atypical of recognized ar ...200617030860
mutagenesis analysis of the ns2b determinants of the alkhurma virus ns2b-ns3 protease activation.alkhurma virus (alkv) is a tick-borne class 4 flavivirus responsible for several human cases of haemorrhagic fever in saudi arabia, with no specific treatment currently available. the viral rna encodes a serine protease (ns2b-ns3), essential for virus replication in infected cells, that constitutes an attractive target for antiviral compounds. in an attempt to identify residues and motifs on ns2b that are necessary for protease activity of the alkv ns2b-ns3 complex, a series of modified ns2b-ns3 ...200617030861
secondary structure of dengue virus type 4 3' untranslated region: impact of deletion and substitution mutations.several studies have generated computer-based predictions of secondary structure of the 3' untranslated region (utr) of dengue virus (den); however, experimental verification of the formation of these structures in vitro is lacking. this study assessed the congruence of mfold predictions of secondary structure of the core region of the den type 4 3' utr with nuclease maps of this region. maps and predictions were largely consistent. maps supported the existence of previously predicted pseudoknot ...200617030863
direct repeats in the 3' untranslated regions of mosquito-borne flaviviruses: possible implications for virus transmission.direct repeats (drs) of 20-45 nucleotide conserved sequences (cs) and repeated cs (rcs), separated by non-conserved sequences up to 100 nucleotides long, were previously described in the 3' untranslated region (3'utr) of the three major mosquito-borne flavivirus (mbfv) subgroups, represented by japanese encephalitis virus, yellow fever virus and dengue virus. each subgroup exhibits a specific pattern of drs, the biological significance of which has not yet been adequately addressed. the drs were ...200617030864
characterization of an immunodominant antigenic site on gb virus c glycoprotein e2 that is involved in cell binding.gb virus type c (gbv-c) is a human flavivirus that may cause persistent infection, although most infected individuals clear viremia and develop antibodies to the envelope glycoprotein e2. to study gbv-c e2 antigenicity and cell binding, murine anti-e2 monoclonal antibodies (mabs) were evaluated to topologically map immunogenic sites on gbv-c e2 and for the ability to detect or block recombinant e2 binding to various cell lines. five competition groups of mabs were identified. groups i and ii did ...200617035329
construction and mutagenesis of an artificial bicistronic tick-borne encephalitis virus genome reveals an essential function of the second transmembrane region of protein e in flavivirus assembly.flaviviruses have a monopartite positive-stranded rna genome, which serves as the sole mrna for protein translation. cap-dependent translation produces a polyprotein precursor that is co- and posttranslationally processed by proteases to yield the final protein products. in this study, using tick-borne encephalitis virus (tbev), we constructed an artificial bicistronic flavivirus genome (tbev-bc) in which the capsid protein and the nonstructural proteins were still encoded in the cap cistron but ...200617035331
insights to substrate binding and processing by west nile virus ns3 protease through combined modeling, protease mutagenesis, and kinetic studies.west nile virus is becoming a widespread pathogen, infecting people on at least four continents with no effective treatment for these infections or many of their associated pathologies. a key enzyme that is essential for viral replication is the viral protease ns2b-ns3, which is highly conserved among all flaviviruses. using a combination of molecular fitting of substrates to the active site of the crystal structure of ns3, site-directed enzyme and cofactor mutagenesis, and kinetic studies on pr ...200617052977
molecular epidemiology of west nile virus in humans.after the introduction of west nile virus into the united states of america in 1999 followed by annual wnv epidemics during the mosquito seasons and spreading of the virus from the east (new york; 1999) to the west of the u.s. (california; 2003/2004) there appeared the question of whether a similar scenario could happen in europe, too. to be able to answer this question the german ministry of health decided to investigate the prevalence and incidence of wnv infections in german blood donors. fir ...200617058495
the 3' untranslated region of tick-borne flaviviruses originated by the duplication of long repeat sequences within the open reading frame.comparative alignment of the 3'untranslated regions (3'utrs) of tick-borne flaviviruses has previously revealed short direct repeat sequences about 25-70 nucleotides long [gritsun, t.s., venugopal, k., zanotto, p.m., mikhailov, m.v., sall, a.a., holmes, e.c., polkinghorne, i., frolova, t.v., pogodina, v.v., lashkevich, v.a., gould, e.a., 1997. complete sequence of two tick-borne flaviviruses isolated from siberia and the uk: analysis and significance of the 5' and 3'-utrs. virus res. 49 (1) 27-3 ...200617063566
peptide inhibitors of west nile ns3 protease: sar study of tetrapeptide aldehyde inhibitors.a series of inhibitors related to the benzoyl-norleucine-lysine-arginine-arginine (bz-nkrr) tetrapeptide aldehyde was synthesized. when evaluated against the west nile virus (wnv) ns3 protease, the measured ic(50) ranges from approximately 1 to 200 microm. concurrently, a modeling study using the recently published crystal structure of the west nile ns3/ns2b protease complex (pdb code 2fp7) was conducted. we found that the crystal structure is relevant in explaining the observed sar for this ser ...200617064076
rapid detection, serotyping and quantitation of dengue viruses by taqman real-time one-step rt-pcr.the use of the polymerase chain reaction (pcr) in molecular diagnosis is now accepted worldwide and has become an essential tool in the research laboratory. in the laboratory, a rapid detection, serotyping and quantitation, one-step real-time rt-pcr assay was developed for dengue virus using taqman probes. in this assay, a set of forward and reverse primers were designed targeting the serotype conserved region at the ns5 gene, at the same time flanking a variable region for all four serotypes wh ...200617000012
the location of asparagine-linked glycans on west nile virions controls their interactions with cd209 (dendritic cell-specific icam-3 grabbing nonintegrin).mammalian cell-derived west nile virus preferentially infects cells expressing the c-type lectin cd209l (dendritic cellspecific icam-3 grabbing nonintegrin-related protein; liver- and lymph node-specific icam-3 grabbing nonintegrin) but not cells expressing cd209 (dendritic cell-specific icam-3 grabbing nonintegrin). in contrast, dengue virus infection is enhanced in cells expressing either attachment factor. the west nile virus envelope (e) protein contains a single n-linked glycosylation site ...200617001080
interleukin-29 uses a type 1 interferon-like program to promote antiviral responses in human hepatocytes.interleukin-28a (il-28a), il-28b and il-29 are a family of class ii cytokines that stimulate antiviral responses through a heterodimeric receptor that is distinct from the type i interferon (ifn) receptor. to better understand how this newly described family of cytokines regulates the antiviral state, we compared various cellular responses elicited by il-29 and ifn-alpha. here we show that these cytokines stimulate similar patterns of signal transducer and activator of transcription 1 (stat-1), ...200617006906
flavivirus activation of plasmacytoid dendritic cells delineates key elements of tlr7 signaling beyond endosomal recognition.tlr7 senses rna in endosomal compartments. tlr7 expression and signaling have been demonstrated in plasmacytoid and myeloid dendritic cells, b cells, and t cells. the regulation of tlr7 signaling can play a crucial role in shaping the immune response to rna viruses with different cellular tropisms, and in developing adjuvants capable of promoting balanced humoral and cell-mediated immunity. we used unique characteristics of two ssrna viruses, dengue virus and influenza virus, to delineate factor ...200617082628
[organization of the karshi virus strain leiv-2247 uz genome and its phylogenetic relationships with other representatives of the flavivirus genus].for the first time, the karshi virus complete genome sequence has been determined and analyzed in this work. the karshi virus was attributed to the tick-borne encephalitis group on the basis of phylogenetic analysis of polyprotein sequencing, as well as partial ns5 of the flavivirus genus. comprehensive analysis of the longed to its own cluster, which includes also the royal farm virus.200617094657
lysine methylation as a routine rescue strategy for protein crystallization.crystallization remains a critical step in x-ray structure determination. because it is not generally possible to rationally predict crystallization conditions, commercial screens have been developed which sample a wide range of crystallization space. while this approach has proved successful in many cases, a significant number of proteins fail to crystallize despite being soluble and monodispersed. it is established that chemical modification can facilitate the crystallization of otherwise intr ...200617098187
cd8(+) t cell-mediated immune responses in west nile virus (sarafend strain) encephalitis are independent of gamma interferon.the flavivirus west nile virus (wnv) can cause fatal encephalitis in humans and mice. it has recently been demonstrated, in an experimental model using wnv strain sarafend and c57bl/6 mice, that both virus- and immune-mediated pathology is involved in wnv encephalitis, with cd8(+) t cells being the dominant subpopulation of lymphocyte infiltrates in the brain. here, the role of activated wnv-immune cd8(+) t cells in mouse wnv encephalitis was investigated further. passive transfer of wnv-immune ...200617098975
enhancement of recombinant soluble dengue virus 2 envelope domain iii protein production in escherichia coli trxb and gor double mutant.the dengue virus is currently the most important flavivirus causing human diseases in the tropical and subtropical regions of the world. the envelope protein domain iii of dengue virus type 2 (d2eiii), which induces protective and neutralizing antibodies, was expressed as an n-terminal fusion to a hexa-histidine tag in escherichia coli. the expression of recombinant d2eiii of 103 amino acids in the soluble form can be achieved using suitable host strains, such as origami, at a low induction temp ...200617116581
seroprevalence of west nile virus in saskatchewan's five hills health region, 2003.the five hills health region of saskatchewan reported the highest west nile virus (wnv) case rates in the 2003 outbreak. a serologic and telephone survey was undertaken to assess the seroprevalence of the virus and the knowledge, attitudes and behaviours of the residents.200617120874
[changes in range of mosquito-borne diseases affected by global climatic fluctuations].climate models suggest the strong possibility of range increase of the diseases transmitted by parasitic arthropods, mostly mosquitoes. in predicting processes of malaria and dengue diseases dispersion the estimation of risk is based mostly on reproduction rate of vector species. these models allow to calculate the critical threshold of host density which is necessary to maintain parasites and pathogens transmission. such studies based on integrated mathematical modelling indicate widespread inc ...200617120987
west nile virus nonstructural protein ns1 inhibits complement activation by binding the regulatory protein factor h.the complement system, by virtue of its dual effector and priming functions, is a major host defense against pathogens. flavivirus nonstructural protein (ns)-1 has been speculated to have immune evasion activity, because it is a secreted glycoprotein, binds back to cell surfaces, and accumulates to high levels in the serum of infected patients. herein, we demonstrate an immunomodulatory function of west nile virus ns1. soluble and cell-surface-associated ns1 binds to and recruits the complement ...200617132743
flavivirus nonstructural protein ns1: complementary surprises. 200617146046
expression of vector-based small interfering rna against west nile virus effectively inhibits virus replication.rna interference is one of the effective emerging anti-viral strategies to inhibit virus infection in cells. in this study, a small interfering rna expressing vector (psilencer-ns5) targeting the ns5 gene of west nile virus (wnv) was employed to target and destroy wnv transcripts. real-time pcr revealed drastic reduction in wnv rna transcripts in psilencer-ns5-transfected vero cells. the virus infectious titre was also significantly reduced by 90% as determined by plaque assays. the resulting de ...200616870272
preliminary characterization of (nucleoside-2'-o-)-methyltransferase crystals from meaban and yokose flaviviruses.viral methyltranferases (mtase) are involved in the third step of the mrna-capping process, transferring a methyl group from s-adenosyl-l-methionine (sam) to the capped mrna. mtases are classified into two groups: (guanine-n7)-methyltransferases (n7mtases), which add a methyl group onto the n7 atom of guanine, and (nucleoside-2'-o-)-methyltransferases (2'omtases), which add a methyl group to a ribose hydroxyl. the mtases of two flaviviruses, meaban and yokose viruses, have been overexpressed, pu ...200616880552
jab1 mediates cytoplasmic localization and degradation of west nile virus capsid protein.the clinical manifestations of west nile virus (wnv), a member of the flavivirus family, include febrile illness, sporadic encephalitis, and paralysis. the capsid (cp) of wnv is thought to participate in these processes by inducing apoptosis through mitochondrial dysfunction and activation of caspase-9 and caspase-3. to further identify the molecular mechanism of the wnv capsid protein (wnvcp), yeast two-hybrid assays were employed using wnv-cp as bait. jab1, the fifth subunit of the cop9 signal ...200616882664
a 5' rna element promotes dengue virus rna synthesis on a circular genome.the mechanisms of rna replication of plus-strand rna viruses are still unclear. here, we identified the first promoter element for rna synthesis described in a flavivirus. using dengue virus as a model, we found that the viral rdrp discriminates the viral rna by specific recognition of a 5' element named sla. we demonstrated that rna-rna interactions between 5' and 3' end sequences of the viral genome enhance dengue virus rna synthesis only in the presence of an intact sla. we propose a novel me ...200616882970
serotype 1-specific monoclonal antibody-based antigen capture immunoassay for detection of circulating nonstructural protein ns1: implications for early diagnosis and serotyping of dengue virus infections.rapid diagnosis and serotyping of dengue virus (dv) infections are important for timely clinical management and epidemiological control in areas where multiple flaviviruses are endemic. however, the speed and accuracy of diagnosis must be balanced against test cost and availability, especially in developing countries. we developed a specific antigen capture enzyme-linked immunosorbent assay (elisa) for early detection and serotyping of dv serotype 1 (dv1) by using well-characterized monoclonal a ...200616891505
parallel infection of japanese encephalitis virus and wolbachia within cells of mosquito salivary glands.the endosymbiont wolbachia usually causes cytoplasmic incompatibility in dipteran hosts, including mosquitoes. however, some important arbovirus-transmitting mosquitoes such as aedes aegypti (l.) are not heritably infected by wolbachia. in wolbachia-harboring mosquito armigeres subalbatus coquillett, colocalization of wolbachia and inoculated japanese encephalitis virus (family flaviviridae, genus flavivirus, jev) in salivary gland (sg) cells was shown by electron microscopy. the infection rate ...200616892635
dengue virus ns4b interacts with ns3 and dissociates it from single-stranded rna.dengue virus, a member of the family flaviviridae of positive-strand rna viruses, has seven non-structural proteins: ns1, ns2a, ns2b, ns3, ns4a, ns4b and ns5. except for enzymic activities contained within ns3 and ns5, the roles of the other proteins in virus replication and pathogenesis are not well defined. in this study, a physical interaction between ns4b and the helicase domain of ns3 was identified by using a yeast two-hybrid assay. this interaction was further confirmed by biochemical pul ...200616894199
the 3' untranslated regions of kamiti river virus and cell fusing agent virus originated by self-duplication.previously, it was shown that the 3' untranslated region (3'utr) of kamiti river virus (krv) is nearly twice as long as the 3'utr of other flaviviruses (1208 nucleotides compared with 730 nucleotides for the longest 3'utr of any virus in the tick-borne encephalitis virus species). additionally, krv and the closely related cell fusing agent virus (cfav) were shown to contain two short, almost perfect repeat sequences of 67 nucleotides. however, the construction of a robust comparative nucleotide ...200616894200
west nile virus in complex with the fab fragment of a neutralizing monoclonal antibody.flaviviruses, such as west nile virus (wnv), are significant human pathogens. the humoral immune response plays an important role in the control of flavivirus infection and disease. the structure of wnv complexed with the fab fragment of the strongly neutralizing mab e16 was determined to 14.5-angstrom resolution with cryo-electron microscopy. e16, an antibody with therapeutic potential, binds to domain iii of the wnv envelope glycoprotein. because of steric hindrance, fab e16 binds to only 120 ...200616895988
manifestations of west nile neuroinvasive disease.since its introduction to north america in 1999, west nile virus, an arthropod-borne flavivirus, has become the most significant cause of epidemic encephalitis in the western hemisphere. while most human infections with the virus are asymptomatic and the majority of symptomatic persons experience febrile illness, severe neurologic manifestations, including meningitis, encephalitis, and poliomyelitis may be seen. this review summarizes the virology, epidemiology and pathogenesis of human infectio ...200616906589
the active essential cfns3d protein complex.the ns2b-ns3 protease complex is essential for the replication of dengue virus, which is the etiologic agent of dengue and hemorrhagic fevers, diseases that are a burden for the tropical and subtropical areas of the world. the active form of the ns3 protease linked to the 40 residues of the ns2b cofactor shows highly flexible and disordered region(s) that are responsible for its high propensity to aggregate at the concentrations necessary for nmr spectroscopy studies or for crystallization. limi ...200616911516
west nile virus 5'-cap structure is formed by sequential guanine n-7 and ribose 2'-o methylations by nonstructural protein 5.many flaviviruses are globally important human pathogens. their plus-strand rna genome contains a 5'-cap structure that is methylated at the guanine n-7 and the ribose 2'-oh positions of the first transcribed nucleotide, adenine (m(7)gpppam). using west nile virus (wnv), we demonstrate, for the first time, that the nonstructural protein 5 (ns5) mediates both guanine n-7 and ribose 2'-o methylations and therefore is essential for flavivirus 5'-cap formation. we show that a recombinant full-length ...200616912287
structure-based mutational analysis of the ns3 helicase from dengue virus.we performed a mutational analysis of the ns3 helicase of dengue virus to test insights gleaned from its crystal structure and identified four residues in the full-length protein that severely impaired either its rtpase and atpase (arg-457-458, arg-460, arg-463) or helicase (ile-365, arg-376) activity. alanine substitution of lys-396, which is located at the surface of domain ii, drastically reduced all three enzymatic activities. our study points to a pocket at the surface of domain ii that may ...200616775356
[west nile virus and its vectors].there are more than five hundred known arthropod-borne viruses (arboviruses) all around the world and approximately hundred of them may cause disease in humans. during the past 20 years there has been a dramatic resurgence or emergence of epidemic arboviral diseases affecting both humans and domestic animals. many factors play important roles in the emergence of arboviral diseases like yellow fever, dengue, west nile encephalitis, and of other diseases such as malaria and leishmaniasis in countr ...200616775967
artificial receptors in serologic tests for the early diagnosis of dengue virus infection.because of the range and nonspecificity of clinical presentations of dengue virus infections, we felt there was a need to create diagnostic tests. we used artificial receptors for the virus to develop serologic assays to detect dengue virus infection.200616777919
inhibition of japanese encephalitis virus ns1 protein expression in cell by small interfering rnas.japanese encephalitis virus (jev), a serious mosquitoborne flavivirus, causes an acute infection of the central system resulting in encephalitis of humans and many kinds of animals. a high proportion of the survivors exhibit neurogical and psychiatric sequelae. ns1 is one of important non-structural proteins, which was found to be associated with viral rna replication. to inhibit ns1 expression, four small interfering rnas (sirnas) expression plasmids (ps-ns1a, ps-ns1b, ps-ns1c and ps-ns1d) were ...200616791421
syndromic surveillance in the netherlands for the early detection of west nile virus epidemics.west nile virus (wnv) is an arthropod-borne flavivirus that is endemic in africa, europe, and eastern asia. the recent introduction and rapid dissemination of the virus in the united states as well as an increase in wnv outbreaks in europe, has raised concerns for its spread in europe. a surveillance system was developed to allow timely detection of an introduction of wnv infections in the netherlands. this program focuses on cases presenting with neurological disease and includes the monitoring ...200616796513
tick-borne encephalitis in eastern france.each y a few cases of tbe infection are described in alsace, france which lies at the occidental limit of the endemic zone of tick-borne encephalitis (tbe). hence we carried out a retrospective epidemiological and clinical study of tbe infection in alsace. data were collected from serological results sent to the institut de virologie (université louis pasteur) in strasbourg. all samples positive for specific igm against tbe were retained. the physician in charge of each patient was asked to prov ...200616798704
pkr and rnase l contribute to protection against lethal west nile virus infection by controlling early viral spread in the periphery and replication in neurons.west nile virus (wnv) is a neurotropic, mosquito-borne flavivirus that can cause lethal meningoencephalitis. type i interferon (ifn) plays a critical role in controlling wnv replication, spread, and tropism. in this study, we begin to examine the effector mechanisms by which type i ifn inhibits wnv infection. mice lacking both the interferon-induced, double-stranded-rna-activated protein kinase (pkr) and the endoribonuclease of the 2',5'-oligoadenylate synthetase-rnase l system (pkr(-/-) x rl(-/ ...200616809306
a preliminary neuropathological study of japanese encephalitis in humans and a mouse model.japanese encephalitis virus is a mosquito-borne flavivirus that causes approximately 10000 deaths annually in asia. after a brief viraemia, the virus enters the central nervous system, but the means of crossing the blood-brain barrier is uncertain. we used routine histological staining, immunohistology and electron microscopy to examine brain material from four fatal human cases, and made comparisons with material from a mouse model. in human material there was oedema, perivascular inflammation, ...200616814333
infectious complications in renal transplant recipients.post-kidney transplant infection is the most common life-threatening complication of long-term immunosuppressive therapy. optimal immunosuppression, in which a balance is maintained between prevention of rejection and avoidance of infection, is the most challenging aspect of posttransplantation care. the study of infectious complications in immunologically compromised recipients is changing rapidly, particularly in the fields of prophylactic and preemptive strategies, molecular diagnostic method ...200616815233
apoptosis in mosquito midgut epithelia associated with west nile virus infection.the mosquito culex pipiens pipiens is a documented vector of west nile virus (wnv, flaviviridae, flavivirus). our laboratory colony of c. p. pipiens, however, was repeatedly refractory to experimental transmission of wnv. our goal was to identify if a cellular process was inhibiting virus infection of the midgut. we examined midguts of mosquitoes fed control and wnv-infected blood meals. three days after feeding, epithelial cells from abdominal midguts of mosquitoes fed on wnv fluoresced under a ...200616820968
short report: the first isolation of japanese encephalitis virus from mosquitoes collected from mainland australia.in response to an incursion of japanese encephalitis virus (jev) on cape york peninsula, australia, in 2005, 23,144 culex mosquitoes were processed for virus detection. a single isolate of jev was obtained from a pool of culex sitiens subgroup mosquitoes. this is the first reported mosquito isolate of jev from the australian mainland.200616837702
diversity of the population of tick-borne encephalitis virus infecting ixodes ricinus ticks in an endemic area of central switzerland (canton bern).tick-borne encephalitis virus (tbev), a member of the genus flavivirus, has a positive-strand rna genome containing a single open reading frame flanked by non-coding regions (ncrs). ixodes ricinus ticks (n = 307) were collected from vegetation in a natural tbev focus in belp, switzerland. the presence and identity of the virus were determined by nested rt-pcr followed by sequencing of the 5'-terminal region that comprises the 5' ncr and the capsid-encoding region (c). the presence of the western ...200616847119
hsp70 functions as a negative regulator of west nile virus capsid protein through direct interaction.west nile virus (wnv) is a member of the flavivirus family and induces febrile illness, sporadic encephalitis, and paralysis. the capsid (cp) of wnv is thought to play a role in inducing these symptoms through caspase-3- and caspase-9-dependent apoptosis. using wnvcp as bait for a yeast two-hybrid assay, we identified that hsp70 interacted with wnvcp. the interaction between hsp70 and wnvcp was further substantiated using purified proteins. deletion analysis of hsp70 indicated that wnvcp could b ...200616854374
fusogenic peptide as diagnostic marker for detection of flaviviruses.dengue, japanese encephalitis, west nile encephalitis, yellow fever are the common flaviviral diseases associated with high morbidity and mortality. the initial symptoms of most of the flaviviral infections are similar to each other as well as to some other viral diseases. making clinical diagnosis, therefore, becomes a challenging task for the clinician. several studies have been reported on using detection of serum antibodies against flavivirus for the diagnosis of specific flaviviral disease; ...200616855316
dengue virus induces expression of cxc chemokine ligand 10/ifn-gamma-inducible protein 10, which competitively inhibits viral binding to cell surface heparan sulfate.dengue virus is an arthropod-borne flavivirus that causes a mild febrile illness, dengue fever, or a potentially fatal syndrome, dengue hemorrhagic fever/dengue shock syndrome. chemokines primarily orchestrate leukocyte recruitment to the areas of viral infection, which makes them critical mediators of immune and inflammatory responses. in the present study, we investigated the induction and function of chemokines in mice early after infection with dengue virus in vivo. we found that cxcl10/ifn- ...200616920957
[west nile virus genotyping among wild birds belonging to ground and tree-brush bird populations on the territories of the baraba forest-steppe and kulunda steppe (2003-2004)].the paper gives the results of the 2003-2004 examinations of 104 wild birds belonging to land tree-brush complexes from the baraba forest-steppe and kulunda steppe for the detection and genotyping west nile virus (wnv). elisa and rt-pcr were used to show that in the forest-steppe and steppe zones of the south of western siberia, wnv circulates among both migrating and settled birds. an analysis of the nucleotide sequence of a protein e gene fragment showed the circulation of wnv genotype ia in t ...200616929594
west nile virus immunoglobulin a (wnv iga) detection in cerebrospinal fluid in relation to wnv igg and igm reactivity.diagnostic criteria for neurologic involvement in wnv infection include wnv igm detection in csf; however, wnv igm can persist in csf >6 months. csf iga characterizes other flavivirus infections, but wnv iga in csf has not been evaluated. wnv igm in csf correlates with igm in serum but the presence of wnv iga in csf compared to serum is unknown.200616939715
crystal structure of west nile virus envelope glycoprotein reveals viral surface epitopes.west nile virus, a member of the flavivirus genus, causes fever that can progress to life-threatening encephalitis. the major envelope glycoprotein, e, of these viruses mediates viral attachment and entry by membrane fusion. we have determined the crystal structure of a soluble fragment of west nile virus e. the structure adopts the same overall fold as that of the e proteins from dengue and tick-borne encephalitis viruses. the conformation of domain ii is different from that in other prefusion ...200616943291
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