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dengue virus m protein contains a proapoptotic sequence referred to as apoptom.the induction of apoptotic cell death is a prominent cytopathic effect of dengue (den) viruses. one of the key questions to be addressed is which viral components induce apoptosis in den virus-infected cells. this study investigated whether the small membrane (m) protein was involved in the induction of apoptosis by den virus. this was addressed by using a series of enhanced green fluorescent protein-fused den proteins. evidence is provided that intracellular production of the m ectodomains (res ...200313679613
association of japanese encephalitis virus ns3 protein with microtubules and tumour susceptibility gene 101 (tsg101) protein.previously reported findings by our group showed that non-structural protein 3 (ns3) of japanese encephalitis virus (jev) was localized mainly in the jev-induced convoluted membrane (cm), which has been proposed to originate from rough endoplasmic reticulum (rer), golgi apparatus or the trans-golgi network (tgn), and serves as a reservoir for viral proteins during virus assembly. earlier findings indicated that ns3 of kunjin virus interacts with microtubules. in addition, one of the golgi-associ ...200313679614
serological evidence of west nile virus, usutu virus and sindbis virus infection of birds in the uk.the introduction and rapid dispersal of the african flavivirus west nile virus (wnv) throughout north america, and the high fatality rate due to encephalitis in birds, horses, other wildlife species and humans, has attracted major attention worldwide. usutu virus, another flavivirus, came to prominence in 2001, when it was identified as the agent responsible for a drop in the bird population in austria; previously this encephalitic virus was found only in birds and mosquitoes in africa. sindbis ...200313679615
mutations which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus type 2/4 vaccine candidate in vero cells.mutations which increase the replication of dengue viruses in cell culture would greatly facilitate the manufacture of both a live attenuated or inactivated dengue virus vaccine. we have identified eight missense mutations in dengue virus type 4 (den4) that increase the plaque size and kinetics of replication of recombinant den4 virus in vero cells. den4 viruses bearing these vero cell adaptation mutations were also evaluated for the level of replication in the brains of mice. two of these eight ...200314505914
genetic systems of west nile virus and their potential applications.prevention and treatment of west nile virus (wnv) and other flavivirus infections have become a global public health priority. this fact is highlighted by the recent epidemic of wnv in the us. since the first outbreak of wnv in the us in 1999, the virus has caused over 4000 known human cases and at least 263 human deaths. the epidemic of wnv in the us in 2002 represents the largest meningoencephalitis outbreak in the western hemisphere, and the largest wnv outbreak ever reported. reverse genetic ...200314508880
sentinel chicken surveillance program in australia, july 2002 to june 2003.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 (kun) virus activity in the region. during the 2002-2003 season low levels of flavivirus activity were detected in northern australia compared to previous years. mve and kun virus activity was detected in the kimberley and pilbara regions of western australia and the northern territory but not in nor ...200314510063
west nile virus-associated meningoencephalitis in two chronically immunosuppressed renal transplant recipients.west nile virus is a mosquito-borne, single-stranded rna virus of the flaviviridae family. approximately 1 in 150 patients who have serologic evidence of west nile virus infection develop encephalitis or meningitis. we report two chronically immunosuppressed renal transplant recipients with confirmed west nile virus meningoencephalitis acquired through community exposure. both patients presented with fever and neurological changes in the autumn of 2002. flavivirus-specific immunoglobulin m in an ...200314510707
molecularly engineered live-attenuated chimeric west nile/dengue virus vaccines protect rhesus monkeys from west nile virus.two molecularly engineered, live-attenuated west nile virus (wn) vaccine candidates were highly attenuated and protective in rhesus monkeys. the vaccine candidates are chimeric viruses (designated wn/den4) bearing the membrane precursor and envelope protein genes of wn on a backbone of dengue 4 virus (den4) with or without a deletion of 30 nucleotides (delta 30) in the 3' noncoding region of den4. viremia in wn/den4- infected monkeys was reduced 100-fold compared to that in wn- or den4-infected ...200314517072
rna-dependent rna polymerase activity of classical swine fever virus ns5b protein expressed in natural host cells.the ns5b gene, cloned from classical swine fever virus (csfv) genome, was expressed in porcine kidney cells pk-15, natural host of csfv. in purifying cytoplasmic extracts from these cells by means of different concentrations of salt, glycerol and detergent four fractions, namely crude supernatant (sc) and different purified supernatants (s1, s2 and s3) were obtained. using western blot analysis the ns5b protein was found in all these fractions, showing that it was soluble in both higher and lowe ...200314524473
imported dengue in french university hospitals: a 6-year survey.dengue fever (df) is a mosquito-transmitted acute disease caused by any of four dengue flavivirus serotypes (den-1, den-2, den-3, and den-4) which is becoming a major public health problem in intertropical areas.1 df is increasingly observed in febrile travelers returning from tropical areas,2 especially those returning from the caribbean islands and southeast asia, but it is rarely diagnosed in travelers returning from africa.3-8 diagnosis is often serologic, and in most cases is not confirmed; ...200314531982
characterisation of human tick-borne encephalitis virus from sweden.viruses of the tick-borne encephalitis (tbe) antigenic complex, within the family flaviviridae, cause a variety of diseases including uncomplicated febrile illness, meningo-encephalitis and haemorrhagic fever. different wildlife species act as reservoir hosts with ixodid tick species as vectors. tbe virus (tbev) causes 40-130 cases confirmed serologically in sweden each year. characteristics of tbev strains circulating in sweden have not been investigated previously and no viral sequence data ha ...200314556277
two distinct size classes of immature and mature subviral particles from tick-borne encephalitis virus.flaviviruses assemble in the endoplasmic reticulum by a mechanism that appears to be driven by lateral interactions between heterodimers of the envelope glycoproteins e and prm. immature intracellular virus particles are then transported through the secretory pathway and converted to their mature form by cleavage of the prm protein by the cellular protease furin. earlier studies showed that when the prm and e proteins of tick-borne encephalitis virus are expressed together in mammalian cells, th ...200314557621
dengue 2 pdk-53 virus as a chimeric carrier for tetravalent dengue vaccine development.attenuation markers of the candidate dengue 2 (d2) pdk-53 vaccine virus are encoded by mutations that reside outside of the structural gene region of the genome. we engineered nine dengue virus chimeras containing the premembrane (prm) and envelope (e) genes of wild-type d1 16007, d3 16562, or d4 1036 virus within the genetic backgrounds of wild-type d2 16681 virus and the two genetic variants (pdk53-e and pdk53-v) of the d2 pdk-53 vaccine virus. expression of the heterologous prm-e genes in the ...200314557629
zooprophylaxis or zoopotentiation: the outcome of introducing animals on vector transmission is highly dependent on the mosquito mortality while searching.zooprophylaxis, the diversion of disease carrying insects from humans to animals, may reduce transmission of diseases such as malaria. however, as the number of animals increases, improved availability of blood meals may increase mosquito survival, thereby countering the impact of diverting feeds.200314565850
cytochrome p450 2a6: a new hepatic autoantigen in patients with chronic hepatitis c virus infection.cytochromes p4502a6 (cyp2a6) and p4501a2 (cyp1a2) were described as hepatic autoantigens in the autoimmune polyglandular syndrome type-1 (aps-1). we evaluated the significance of anti-cyp2a6 and anti-cyp1a2 in several hepatic diseases in the absence of aps-1.200314568264
[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.200316724440
[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 ...200319753724
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 ...200321765762
[the prevalence of hepatitis g virus in patients with hepatitis b and c virus infections].gb virus c/hepatitis g virus (gbv-c/hgv) is a recently identified flavivirus, which has been frequently detected in patients with chronic hepatitis b virus (hbv) and hepatitis c virus (hcv) infections. in this study, the prevalence of hgv-rna and antibodies to e2 envelope antigen (anti-e2) which is a marker of past infection, have been investigated in the samples of patients with hcv and hbv infections, and the prevalence rates were compared with the control group. the study group consisted of 5 ...200415700668
serological studies of west nile virus in a liver transplant population.background: solid organ transplant populations are at increased risk for serious clinical manifestations of west nile virus (wnv) infection. objective: to monitor liver transplant recipients during the 2003 wnv season in manitoba and to identify incidence, clinical presentation and serology. methods: serial blood specimens were obtained from adult patients followed at the liver transplant outpatient clinic between may 2003 and october 2003. studies for wnv infection included immunoglobulin (ig) ...200418159505
conformational changes of the flavivirus e glycoprotein.dengue virus, a member of the flaviviridae family, has a surface composed of 180 copies each of the envelope (e) glycoprotein and the membrane (m) protein. the crystal structure of an n-terminal fragment of e has been determined and compared with a previously described structure. the primary difference between these structures is a 10 degrees rotation about a hinge relating the fusion domain dii to domains di and diii. these two rigid body components were used for independent fitting of e into t ...200415341726
susceptibility of mosquito and tick cell lines to infection with various flaviviruses.the genus flavivirus consists of more than 70 virus species and subtypes, the majority of which are transmitted by mosquitoes or ticks, although some have no known vector (nkv). the ability of these viruses to infect cultured cells derived from mosquito or tick species offers a useful insight into the suitability of such vectors to harbour and replicate particular viruses. we undertook a comparative study of the susceptibility of mammalian vero cells, a clonal mosquito cell line (c6/36) and rece ...200415347394
flavivirus isolations from mosquitoes collected from saibai island in the torres strait, australia, during an incursion of japanese encephalitis virus.adult mosquitoes (diptera: culicidae) were collected in january and february 2000 from saibai island in the torres strait of northern australia, and processed for arbovirus isolation during a period of japanese encephalitis (je) virus activity on nearby badu island. a total of 84 210 mosquitoes were processed for virus isolation, yielding six flavivirus isolates. viruses obtained were single isolates of je and kokobera (kok) and four of kunjin (kun). all virus isolates were from members of the c ...200415347396
[molecular analysis of hepatitis c virus in pathogenesis of chronic hepatitis c]. 200415359835
can we really learn from model pathogens?cytolytic t (tc) lymphocytes are the first order response of the adaptive immune system in the recovery from primary viral infections. these effector cells execute their function either by direct cytotoxicity through the fas or perforin pathway and/or by the release of cytokines that either directly or indirectly exert antiviral activity. mice respond to infection by closely related viruses with a vigorous tc response, which is characterized by extensive crossreactivity on target cells infected ...200415364054
use of recombinant e protein domain iii-based enzyme-linked immunosorbent assays for differentiation of tick-borne encephalitis serocomplex flaviviruses from mosquito-borne flaviviruses.the serological diagnosis of infection by flaviviruses is complicated by the presence of flavivirus cross-reactive antibodies that produce false-positive results for flavivirus infections, especially in regions where more than one virus is endemic. current diagnostic reagents for tick-borne flavivirus infection have been found to cross-react with yellow fever- or dengue virus-positive sera. this study utilized recombinant flavivirus e protein domain 3 (re-d3) as a diagnostic reagent to different ...200415364996
n- t-boc-amino acid esters of isomannide. potential inhibitors of serine proteases.hepatitis c, dengue and west nile virus are some of the most important flaviviruses, that share one important serine protease enzyme. serine proteases are the most studied class of proteolytic enzyme and, in these cases, a primary target for drug discovery. in this paper, we describe the synthesis and preliminary molecular modeling studies of a novel class of n- t-boc amino acid esters derived of isomannide as potential serine proteases inhibitors.200415365909
infectious entry of west nile virus occurs through a clathrin-mediated endocytic pathway.the pathway of west nile flavivirus early internalization events was mapped in detail in this study. overexpression of dominant-negative mutants of eps15 strongly inhibits west nile virus (wnv) internalization, and pharmacological drugs that blocks clathrin also caused a marked reduction in virus entry but not caveola-dependent endocytosis inhibitory agent, filipin. using immunocryoelectron microscopy, wnv particles were seen within clathrin-coated pits after 2 min postinfection. double-labeling ...200415367621
different chemokine expression in lethal and non-lethal murine west nile virus infection.west nile (wn) virus is a mosquito-borne flavivirus that can cause lethal encephalitis in humans and horses. the wn virus endemic in new york city (ny) in 1999 caused large-scale mortality of wild birds that was not evident in endemic areas in other parts of the world, and the pathogenesis of the wn virus strain isolated in ny (ny strain) appears to differ from that of previously isolated strains. however, the pathogenesis of ny strain infection remains unclear. this study examined cc (rantes/cc ...200415368509
cytopathological changes induced by selected brazilian flaviviruses in mouse macrophages.scanning and transmission electron microscopy were used to analyse the ultrastructure of peritoneal mouse macrophage cells infected with brazilian flavivirus (yellow fever, rocio, bussuquara and saint louis encephalitis viruses). macrophage cells collected 3 days after viral infection had a flattened shape, with an increased number of large spikes of cytoplasm prolongations, giving an appearance of hairy cells. cytopathological changes to the macrophage cells were similar regardless of the infec ...200415369478
in vivo monitoring of acute flavivirus (modoc) encephalitis with regional and whole-brain quantitative diffusion magnetic resonance imaging.in vivo imaging of structural changes in the brain of patients with encephalitis has become an important aid in diagnostic and therapeutic procedures. diffusion-weighted magnetic resonance imaging (dwi) was employed to quantitate regional and whole-brain diffusion-weighted mri changes in a hamster model for acute flavivirus encephalitis. the regional apparent diffusion coefficient (adc) was determined in hyperintense regions seen on t2-weighted images (i.e., the thalamic area and the temporal lo ...200415371156
experimental usutu virus infection of suckling mice causes neuronal and glial cell apoptosis and demyelination.usutu virus (usuv), a mosquito-borne flavivirus of the japanese encephalitis virus group has been responsible for avian mortality in austria since 2001. in the present study, the neuropathogenicity and neuroinvasiveness of usuv for 1-week-old suckling mice was investigated. after intraperitoneal inoculation, clinical signs like depression, disorientation, paraplegia, paralysis and coma were observed between 6 and 11 days post infection. histologically, there was widespread neuronal apoptosis esp ...200415372281
specific interaction between the classical swine fever virus ns5b protein and the viral genome.the ns5b protein of the classical swine fever virus (csfv) is the rna-dependent rna polymerase of the virus and is able to catalyze the viral genome replication. the 3' untranslated region is most likely involved in regulation of the pestivirus genome replication. however, little is known about the interaction between the csfv ns5b protein and the viral genome. we used different rna templates derived from the plus-strand viral genome, or the minus-strand viral genome and the csfv ns5b protein ob ...200415373834
transmission cycles, host range, evolution and emergence of arboviral disease.many pandemics have been attributed to the ability of some rna viruses to change their host range to include humans. here, we review the mechanisms of disease emergence that are related to the host-range specificity of selected mosquito-borne alphaviruses and flaviviruses. we discuss viruses of medical importance, including venezuelan equine and japanese encephalitis viruses, dengue viruses and west nile viruses.200415378043
dengue-specific cd8+ t cells have both protective and pathogenic roles in dengue virus infection.to analyze roles of memory t cells in the pathogenesis of dengue (den) virus infection, a den virus-specific cd8+ cell clone (2d42 cell) was employed to investigate its in vivo function after den virus infection using an animal model. hepg2 grafted severe combined immunodeficient (hepg2-grafted scid) mice were divided into three groups--group a: hepg2-grafted scid mice were inoculated intraperitoneally (ip) with 2d42 cells and then ip-infected with den virus type 2 (den-2); group b: hepg2-grafte ...200415388257
single point mutation in tick-borne encephalitis virus prm protein induces a reduction of virus particle secretion.flaviviruses are assembled to bud into the lumen of the endoplasmic reticulum (er) and are secreted through the vesicle transport pathway. virus envelope proteins play important roles in this process. in this study, the effect of mutations in the envelope proteins of tick-borne encephalitis (tbe) virus on secretion of virus-like particles (vlps), using a recombinant plasmid expression system was analysed. it was found that a single point mutation at position 63 in prm induces a reduction in secr ...200415448368
purification and crystallization reveal two types of interactions of the fusion protein homotrimer of semliki forest virus.the fusion proteins of the alphaviruses and flaviviruses have a similar native structure and convert to a highly stable homotrimer conformation during the fusion of the viral and target membranes. the properties of the alpha- and flavivirus fusion proteins distinguish them from the class i viral fusion proteins, such as influenza virus hemagglutinin, and establish them as the first members of the class ii fusion proteins. understanding how this new class carries out membrane fusion will require ...200415016874
longitudinal studies of west nile virus infection in avians, yucatán state, méxico.following the introduction of west nile virus (wnv) into north america in 1999, surveillance for evidence of infection with this virus in migratory and resident birds was established in yucatán state, méxico in march 2000. overall, 8611 birds representing 182 species and 14 orders were captured and assayed for antibodies to wnv. of these, 5066 (59%) birds were residents and 3545 (41%) birds were migrants. twenty-one (0.24%) birds exhibited evidence of flavivirus infection. of these, 8 birds had ...200415018768
detection of australasian flavivirus encephalitic viruses using rapid fluorogenic taqman rt-pcr assays.the development of single, sensitive, fluorogenic reverse transcriptase-polymerase chain reaction (taqman) assays were required for the rapid and specific detection of three encephalitic viruses found in the australasian region, namely; japanese encephalitis virus (jev), murray valley encephalitis virus (mvev), and kunjin virus (kunv). primers and a fluorogenic probe were individually designed to be complementary to a nucleotide region encompassing the 3' terminus of the nonstructural (ns) 5 gen ...200415041213
myristoylation of viral and bacterial proteins. 200415051068
recent advancement in flavivirus vaccine development.lately, the magnitude of cumulative diseases burden caused by flaviviruses, such as dengue virus, japanese encephalitis virus, tick-borne encephalitis virus, west nile virus and yellow fever virus, has reached an unprecedented level with the sizes of human and animal populations at risk increasing sharply. these diseases present highly complex medical, economic and ecologic problems, some effecting primarily human and others affecting human, livestock and wildlife. the large body of recent publi ...200415056045
exocytosis and fas mediated cytolytic mechanisms exert protection from west nile virus induced encephalitis in mice.infection of mice with the flaviviruses west nile virus (wnv) and murray valley encephalitis (mve) induces cytolytic t-cell responses which are highly cross-reactive on target cells infected with heterologous flaviviruses. of c57bl/6 mice infected with low doses (10(2)-10(6) pfu) of either virus, 30-40% develop encephalitis and die within 10-12 days. mice with defects in the fas or granule exocytosis (perforin and granzymes a and b) pathway of cellular cytotoxicity display reduced mortality and ...200415061770
routes of inoculation and the immune response to a resolving genital flavivirus infection in a novel murine model.the prolonged, abnormal immune response patterns produced by many sexually transmitted viruses have been intensively studied. because normal antiviral immune responses in the vagina are less well-defined, we developed a resolving murine model using vaginal inoculation with the flavivirus, west nile virus. infection resulted in 12% mortality, with sterile protective immunity to vaginal or systemic re-challenge. b-cell numbers increased in the vaginal mucosa from day 1-7 after primary infection, w ...200415061771
evidence that a mechanism for efficient flavivirus budding upregulates mhc class i.an appealing hypothesis for the biological role of flavivirus-induced, interferon-independent, upregulation of mhc class i on the surface of infected cells is that of viral immune evasion from nk cell recognition. here we show that a mechanism for efficient flavivirus morphogenesis interferes with the mhc class i pathway, using a flavivirus budding mutant and recombinant expression of wild-type and mutant forms of the flavivirus structural proteins. we propose that the phenomenon of flavivirus-m ...200415061772
rna interference, arthropod-borne viruses, and mosquitoes.rna interference (rnai) probably functions as an antiviral mechanism in most eukaryotic organisms. variations in the activity of this antiviral pathway in mosquitoes could explain, in part, why some mosquitoes are competent vectors of medically important, arthropod-borne viruses (arboviruses) and others are not. there are three lines of evidence that show the rnai pathway exists in aedes species that transmit arboviruses. the first is that recombinant sindbis viruses expressing a rna fragment fr ...200415068882
west nile virus: pathogenesis and therapeutic options.west nile virus, a member of the family flaviviridae, has spread throughout the united states. with more than 9000 cases and 200 deaths in 2003, west nile virus has become the most common cause of viral encephalitis in several states. west nile virus encephalitis is a zoonosis. the life cycle of the virus includes mainly birds as hosts and mosquitoes as vectors. humans are accidental hosts, insufficient to support the life cycle of the virus because of low-grade, transient viremia. however, huma ...200415068983
functional and structural similarities between the internal ribosome entry sites of hepatitis c virus and porcine teschovirus, a picornavirus.initiation of protein synthesis on picornavirus rna requires an internal ribosome entry site (ires). typically, picornavirus ires elements contain about 450 nucleotides (nt) and use most of the cellular translation initiation factors. however, it is now shown that just 280 nt of the porcine teschovirus type 1 talfan (ptv-1) 5' untranslated region direct the efficient internal initiation of translation in vitro and within cells. in toeprinting assays, assembly of 48s preinitiation complexes from ...200415078929
la protein binds to ns5 and ns3 and to the 5' and 3' ends of dengue 4 virus rna.in vitro replication of dengue virus requires the presence of cis-acting elements within the 5' end and the 3' utr of the viral genome. some, like the putative cyclization sites (pcs), may promote interaction at both ends of the viral genome. to investigate whether viral or cellular proteins could be involved in this interaction, uv-induced cross-linking assays using extracts from the monocytic cell line u937 were performed. our data demonstrate that the 5' end and the 3' utr with the pcs intera ...200415084396
the non-structural 3 (ns3) protein of dengue virus type 2 interacts with human nuclear receptor binding protein and is associated with alterations in membrane structure.flaviviral infections produce a distinct array of virus-induced intracellular membrane alterations that are associated with the flaviviral replication machinery. currently, it is still unknown which flaviviral protein(s) is/are responsible for this induction. using yeast two-hybrid and co-immunoprecipitation analyses, we demonstrated that the ns3 protein of dengue virus type 2 interacted specifically with nuclear receptor binding protein (nrbp), a host cellular protein that influences traffickin ...200415084397
spinal cord neuropathology in human west nile virus infection.during the 1999 new york city west nile virus (wnv) outbreak, 4 patients with profound muscle weakness, attributed to guillain-barré syndrome, were autopsied. these cases were the first deaths caused by wnv, a flavivirus, to be reported in the united states. the patients' brains had signs of mild viral encephalitis; spinal cords were not examined. during the 2002 national epidemic, several patients in mississippi had acute flaccid paralysis. electrophysiologic studies localized the lesions to th ...200415086282
viral vaccine meeting held in barcelona, october 25-28, 2003. 200415098545
conserved rna secondary structures in flaviviridae genomes.presented here is a comprehensive computational survey of evolutionarily conserved secondary structure motifs in the genomic rnas of the family flaviviridae: this virus family consists of the three genera flavivirus, pestivirus and hepacivirus and the group of gb virus c/hepatitis g virus with a currently uncertain taxonomic classification. based on the control of replication and translation, two subgroups were considered separately: the genus flavivirus, with its type i cap structure at the 5' ...200415105528
conserved amino acids 193-324 of non-structural protein 3 are a dominant source of peptide determinants for cd4+ and cd8+ t cells in a healthy japanese encephalitis virus-endemic cohort.our earlier identification of the non-structural protein 3 (ns3) of japanese encephalitis virus (jev) as a dominant cd4+ as well as cd8+ t cell-eliciting antigen in a healthy jev-endemic cohort with a wide hla distribution implied the presence of several epitopes dispersed over the length of the protein. use of various truncated versions of ns3 in lymphocyte stimulation and interferon (ifn)-gamma secretion assays revealed that amino acids (aa) 193-324 of ns3 were comparable with, if not superior ...200415105530
accumulation of a 3'-terminal genome fragment in japanese encephalitis virus-infected mammalian and mosquito cells.japanese encephalitis virus (jev) contains a single positive-strand rna genome nearly 11 kb in length and is not formally thought to generate subgenomic rna molecules during replication. here, we report the abundant accumulation of a 3'-terminal 521- to 523-nucleotide (nt) genome fragment, representing a major portion of the 585-nt 3' untranslated region, in both mammalian (bhk-21) and mosquito (c6/36) cells infected with any of nine strains of jev. in bhk-21 cells, the viral genome was detected ...200415113895
molecular determinants of virulence of west nile virus in north america.west nile virus (wnv) is a mosquito-borne flavivirus that until very recently had not been found in the americas. in 1999, there was an outbreak of west nile encephalitis in new york and surrounding areas, involving 62 human cases, including 7 fatalities. the virus has subsequently become established in the united states of america (u.s.) with 4156 human cases, including 284 deaths, in 2002. the wnv strains found in the u.s. are members of "lineage i", a genetic grouping that includes viruses fr ...200415119761
evolution and dispersal of encephalitic flaviviruses.there are two major groups of encephalitic flaviviruses, those that infect and are transmitted by ticks, particularly ixodes spp. and those that infect and are transmitted by mosquitoes, particularly culex spp. the tick-borne encephalitic flaviviruses exhibit evolutionary characteristics that are largely determined by the protracted life cycle of the tick, its habitat and the prevailing climatic conditions. these viruses appear to have evolved gradually from non-encephalitic viruses that radiate ...200415119763
the entry machinery of flaviviruses.we have been using the flavivirus tick-borne encephalitis virus (tbev) as a model system for investigating the molecular mechanisms underlying the membrane fusion process mediated by a class ii viral fusion protein, the flavivirus envelope protein e. in the mature virion this protein exists as a metastable dimer that dissociates at the acidic ph in endosomes and is converted into a more stable trimeric conformation. the dimer dissociation step liberates an internal fusion peptide that interacts ...200415119768
neurovirulence and host factors in flavivirus encephalitis--evidence from clinical epidemiology.japanese encephalitis virus (jev) and west nile virus (wnv) provide some of the most important examples of emerging zoonotic viral encephalitides. for these flaviviruses, only a small proportion of those infected develop clinical features, and these may range from a non-specific flu-like illness to a severe fatal meningoencephalitis, often with parkinsonian features, or a poliomyelitis-like flaccid paralysis. the factors governing the clinical presentations, and outcome of flavivirus infections ...200415119771
a novel principle of attenuation for the development of new generation live flavivirus vaccines.the genus flavivirus includes a number of important human pathogens that impose major health problems in large regions of the world. the emergence of flaviviruses in new geographic regions (e.g., west nile virus in north america) and rapid socioeconomic changed in many developing countries where flaviviruses such as dengue virus and japanese encephalitis virus and endemic demand the development of new vaccines against these diseases. using tick-borne encephalitis virus as a model we have establi ...200415119774
serosurveillance for japanese encephalitis in children in several districts of west bengal, india.to evaluate the prevalence of antibodies to flaviviruses, particularly japanese encephalitis (je) in children.200415124845
hepatitis c virus glycoprotein e2 contains a membrane-proximal heptad repeat sequence that is essential for e1e2 glycoprotein heterodimerization and viral entry.the e1 and e2 glycoproteins of hepatitis c virus form a noncovalently associated heterodimer that mediates viral entry. glycoprotein e2 comprises a receptor-binding domain (residues 384-661) that is connected to the transmembrane domain (residues 716-746) via a highly conserved sequence containing a hydrophobic heptad repeat (residues 675-699). alanine- and proline-scanning mutagenesis of the e2 heptad repeat revealed that leu675, ser678, leu689, and leu692 are important for e1e2 heterodimerizat ...200415136562
[west nile virus. an unusual flavivirus with increased importance]. 200415137587
clinical and neuroradiologic features of 39 consecutive cases of west nile virus meningoencephalitis.west nile virus (wnv) is a flavivirus wnv that has spread westwards across north america in recent years. it can cause a febrile illness and infection of the central nervous system, which is associated with poor outcome.200415140603
virus inactivation by nucleic acid extraction reagents.many assume that common methods to extract viral nucleic acids are able to render a sample non-infectious. it may be that inactivation of infectious virus is incomplete during viral nucleic acid extraction methods. accordingly, two common viral nucleic acid extraction techniques were evaluated for the ability to inactivate high viral titer specimens. in particular, the potential for trizol ls reagent (invitrogen corp., carlsbad, ca) and avl buffer (qiagen, valencia, ca) were examined to render s ...200415158603
[molecular typing of the tick-borne encephalitis virus isolated from patients with different-infection severities in the south of russia's far east].the thick-borne encephalitis virus (tbev), which is widespread in the eurasian continent, belongs to the flaviviridae family, flavirus genus, and comprises the far eastern, siberian and west european subtypes. it was for the first time that the gene part of the e 24 strain envelope glycoprotein of tbev, which caused infection in residents of the south of russia's far east, was analyzed. it was established that the tbev far-eastern subtype causes different-severity disease cases ranging from the ...200415164719
molecular determinants of antigenicity of two subtypes of the tick-borne flavivirus omsk haemorrhagic fever virus.in 1964, d. h. clarke defined two antigenic subtypes of omsk haemorrhagic fever virus (ohfv) based on polyclonal antibody absorption and haemagglutination assays. the current report defines the molecular basis for these antigenic subtypes by comparison of the complete genomes of ohfv strains kubrin (subtype i) and bogoluvovska (subtype ii). there were six nucleotide differences between these two strains throughout the entire genome and they encoded four amino acid changes including three in the ...200415166446
methylene blue photoinactivation of rna viruses.we present a review of the current status of the use of methylene blue (mb) photoinactivation of viruses starting with the first early observations up to its current use to inactivate hiv-1 in blood products. basic mechanism of action studies conducted with model bacteriophages indicate that mb-photomediated viral rna-protein crosslinkage is a primary lesion and that oxygen, specifically singlet oxygen, is very important also. basic studies on the mechanism of action with hiv are lacking; howeve ...200415168794
flaviviruses and apoptosis regulation. 200415171612
dengue virus serotyping based on envelope and membrane and nonstructural protein ns1 serotype-specific capture immunoglobulin m enzyme-linked immunosorbent assays.envelope and membrane (e/m) and nonstructural protein ns1 serotype-specific capture immunoglobulin m (igm) enzyme-linked immunosorbent assays (elisas) were developed to differentiate four dengue virus serotypes. a total of 93 anti-dengue virus igm-positive serum samples collected between days 5 and 45 of illness from 59 confirmed dengue patients were analyzed. the results showed that positive serotype specificity could be identified for 86.1 and 47.6% of serum samples tested for e/m-specific igm ...200415184425
[circulation of west nile virus (flaviviridae, flavivirus) and some other arboviruses in the ecosystems of volga delta, volga-akhtuba flood-lands and adjoining arid regions (2000-2002)].comprehensive virological, serological as well as genetic studies of the ecology of west nile virus (wnv) as well as of some other arboviruses were undertaken in different ecosystems in the territories of the astrakhan region and of the kalmyk republic. the main carriers (mosquitoes, ticks, birds and mammals) were defined as involved in the circulation of viruses within the natural and anthropogenic biocenosis. phylogenetic examinations of isolated strains and samples, which were positive in rt- ...200415188655
encephalomyelitis from west nile flavivirus in 3 alpacas. 200415188827
solution structure and antibody binding studies of the envelope protein domain iii from the new york strain of west nile virus.the solution structure of domain iii from the new york west nile virus strain 385-99 (wn-red3) has been determined by nmr methods. the west nile domain iii structure is a beta-barrel structure formed from seven anti-parallel beta-strands in two beta-sheets. one anti-parallel beta-sheet consists of beta-strands beta1 (phe(299)-asp(307)), beta2 (val(313)-tyr(319)), beta4 (arg(354)-leu(355)), and beta5 (lys(370)-glu(376)) arranged so that beta2 is flanked on either side by beta1 and beta5. the shor ...200415190071
[tick-borne human pathogenic microorganisms found in europe and those considered nonpathogenic. part i: ticks and viruses].the importance of tick-borne encephalitis (tbe) and lyme borreliosis-the main european tick-borne diseases-is steadily growing. this fact is due to many different factors including climate changes. however, across europe many other human pathogenic viruses, bacteria, and parasites are found in ticks. this article gives an overview of tick-borne human pathogenic viruses present in europe as well as those considered nonpathogenic. it also deals with the various species of vector-competent ticks. a ...200415205783
yellow fever outbreak, imatong, southern sudan.in may 2003, the world health organization received reports about a possible outbreak of a hemorrhagic disease of unknown cause in the imatong mountains of southern sudan. laboratory investigations were conducted on 28 serum samples collected from patients in the imatong region. serum samples from 13 patients were positive for immunoglobulin m antibody to flavivirus, and serum samples from 5 patients were positive by reverse transcription-polymerase chain reaction with both the genus flavivirus- ...200415207058
regulation of antigen processing and presentation molecules in west nile virus-infected human skin fibroblasts.infection of humans with the west nile flavivirus principally occurs via tick and mosquito bites. here, we document the expression of antigen processing and presentation molecules in west nile virus (wnv)-infected human skin fibroblast (hff) cells. using a new flavivirus-specific antibody, 4g4, we have analyzed cell surface human leukocyte antigen (hla) expression on virus-infected cells at a single cell level. using this approach, we show that west nile virus infection alters surface hla expres ...200415207616
live flavivirus vaccines: reasons for caution.context: dengue, japanese encephalitis, tick-borne encephalitis, yellow fever, and west nile viruses cause substantial morbidity and mortality each year. modern transportation and the relaxation of mosquito-control measures are largely responsible for the increase of disease caused by flaviviruses. without effective antiviral drugs, vaccination offers the best chance of decreasing the incidence of these diseases, and live virus vaccines are the most promising and cost effective. however, flavivi ...200415207960
stiff-person syndrome following west nile fever.stiff-person syndrome is a rare autoimmune disorder associated with antibodies against glutamic acid decarboxylase (gad), the key enzyme in gamma-aminobutyric acid synthesis. in most cases, a trigger cannot be identified.200415210535
sequences of flavivirus-related rna viruses persist in dna form integrated in the genome of aedes spp. mosquitoes.flavivirus-related sequences have been discovered in the dsdna genome of aedes albopictus and aedes aegypti mosquitoes, demonstrating for the first time an integration into a eukaryotic genome of a multigenic sequence from an rna virus that replicates without a recognized dna intermediate. in the aedes albopictus c6/36 cell line, an open reading frame (orf) of 1557 aa with protease/helicase and polyprotein processing domains characteristic of flaviviruses was identified. it is closely related to ...200415218182
exchanging the yellow fever virus envelope proteins with modoc virus prm and e proteins results in a chimeric virus that is neuroinvasive in scid mice.a chimeric flavivirus infectious cdna was constructed by exchanging the premembrane (prm) and envelope (e) genes of the yellow fever virus vaccine strain 17d (yf17d) with the corresponding genes of modoc virus (mod). this latter virus belongs to the cluster of the "not-known vector" flaviviruses and is, unlike yf17d, neuroinvasive in scid mice. replication of in vitro-transcribed rna from this chimeric flavivirus was shown by [(3)h]uridine labeling and rna analysis. expression of the mod prm and ...200415220415
west nile: worldwide current situation in animals and humans.west nile (wn) virus is a mosquito-borne flavivirus that is native to africa, europe, and western asia. it mainly circulates among birds, but can infect many species of mammals, as well as amphibians and reptiles. epidemics can occur in rural as well as urban areas. transmission of wn virus, sometimes involving significant mortality in humans and horses, has been documented at erratic intervals in many countries, but never in the new world until it appeared in new york city in 1999. during the n ...200415225984
distribution of e and ns1 proteins of tbe virus in mammalian and tick cells.four monoclonal antibodies recognizing tbev proteins were prepared. three of them (2/h6, 8/a10, 5/f9) specifically recognize the structural e protein and the fourth binds to the nonstructural ns1 protein. these antibodies were used for an immunofluorescence study of tbev protein distribution in infected mammalian host and tick vector tissue culture cells. any differences in the distribution of the e and ns1 proteins were revealed. in porcine ps cell line the proteins were localized in the cytopl ...200415227801
west nile virus infection of horses.west nile virus (wnv) is a flavivirus closely related to japanese encephalitis and st. louis encephalitis viruses that is primarily maintained in nature by transmission cycles between mosquitoes and birds. occasionally, wnv infects and causes disease in other vertebrates, including humans and horses. west nile virus has re-emerged as an important pathogen as several recent outbreaks of encephalomyelitis have been reported from different parts of europe in addition to the large epidemic that has ...200415236677
backbone and side chain resonance assignments of domain iii of the tick-borne langat flavivirus envelope protein. 200415243186
tick-borne encephalitis in childhood--consensus 2004.tick-borne encephalitis (tbe) is a communicable disease caused by a flavi-virus, ticks being the main vectors. the nervous system is affected, four clinical features of different severity are observed: meningitis, meningoencephalitis, meningoencephalomyelitis, meningoradiculoneuritis. tbe is a preventable disease, which is rapidly becoming a growing public health problem in europe. so far no causal treatment is possible but an efficient, safe vaccination is available. during the 6th meeting of t ...200415244050
solution structure and structural dynamics of envelope protein domain iii of mosquito- and tick-borne flaviviruses.the mosquito-borne west nile (wnv) and dengue 2 (den2v) viruses and tick-borne langat (lgtv) and omsk hemorrhagic fever (ohfv) viruses are arthropod-borne flaviviruses (family flaviviridae, genus flavivirus). these viruses are quite similar at both the nucleotide and amino acid level, yet they are very divergent in their biological properties and in the diseases they cause. the objective of this study was to examine the putative receptor-binding domains of the flaviviruses, the envelope (e) prot ...200415248774
isolation of capsid protein dimers from the tick-borne encephalitis flavivirus and in vitro assembly of capsid-like particles.flaviviruses have a spherical capsid that is composed of multiple copies of a single capsid protein and, in contrast to the viral envelope, apparently does not have an icosahedral structure. so far, attempts to isolate distinct particulate capsids and soluble forms of the capsid protein from purified virions as well as to assemble capsid-like particles in vitro have been largely unsuccessful. here we describe the isolation of nucleocapsids from tick-borne encephalitis (tbe) virus and their disin ...200415254179
structure and function of the 3' terminal six nucleotides of the west nile virus genome in viral replication.using a self-replicating reporting replicon of west nile (wn) virus, we performed a mutagenesis analysis to define the structure and function of the 3'-terminal 6 nucleotides (nt) (5'-ggaucu(oh)-3') of the wn virus genome in viral replication. we show that mutations of nucleotide sequence or base pair structure of any of the 3'-terminal 6 nt do not significantly affect viral translation, but exert discrete effects on rna replication. (i). the flavivirus-conserved terminal 3' u is optimal for wn ...200415254187
common e protein determinants for attenuation of glycosaminoglycan-binding variants of japanese encephalitis and west nile viruses.natural isolates and laboratory strains of west nile virus (wnv) and japanese encephalitis virus (jev) were attenuated for neuroinvasiveness in mouse models for flavivirus encephalitis by serial passage in human adenocarcinoma (sw13) cells. the passage variants displayed a small-plaque phenotype, augmented affinity for heparin-sepharose, and a marked increase in specific infectivity for sw13 cells relative to the respective parental viruses, while the specific infectivity for vero cells was not ...200415254199
west nile virus infection.the epidemiology, virology, and transmission of west nile virus (wnv) are reviewed, and the clinical features, diagnosis, and treatment of wnv infection are examined.200415259752
action of celgosivir (6 o-butanoyl castanospermine) against the pestivirus bvdv: implications for the treatment of hepatitis c.alpha-glucosidase i inhibitors have been shown to inhibit the replication of a broad range of enveloped viruses by preventing the correct folding of their envelope glycoproteins. this study assesses the potential of 6 o-butanoyl castanospermine (celgosivir) as a treatment for hepatitis c virus (hcv). in the absence of an adequate culture system for hcv, the closely related virus, bovine viral diarrhoea virus (bvdv), was used as a surrogate model. using both a plaque assay and a cytopathic effect ...200415266896
west nile virus vaccines.west nile virus (wnv) is a mosquito-borne flavivirus that is emerging as a global pathogen. in the last decade, virulent strains of the virus have been associated with significant outbreaks of human and animal disease in europe, the middle east and north america. efforts to develop human and veterinary vaccines have taken both traditional and novel approaches. a formalin-inactivated whole virus vaccine has been approved for use in horses. dna vaccines coding for the structural wnv proteins have ...200415268663
flavivirus encephalitis. 200415269317
detection of genome-scale ordered rna structure (gors) in genomes of positive-stranded rna viruses: implications for virus evolution and host persistence.discrete rna secondary and higher-order structures, typically local in extent, play a fundamental role in rna virus replication. using new bioinformatics analysis methods, we have identified genome-scale ordered rna structure (gors) in many genera and families of positive-strand animal and plant rna viruses. there was remarkably variability between genera that possess this characteristic; for example, hepaciviruses in the family flaviviridae show evidence for extensive internal base-pairing thro ...200415273323
pathology and viral distribution in fatal usutu virus infections of birds from the 2001 and 2002 outbreaks in austria.in the summer of 2001, usutu virus (usuv) was isolated for the first time in europe, from an episode of mass mortality in eurasian blackbirds (turdus merula). in the present study, 40 of the birds (representing three species), confirmed as cases of usuv infection, were examined by four methods (histopathology, immunohistochemistry [ihc], in-situ hybridization [ish] and reverse-transcriptase polymerase chain reaction [rt-pcr]). the major macroscopical finding was hepatosplenomegaly; histologicall ...200415276857
modulation of dengue virus infection of dendritic cells by aedes aegypti saliva.dengue virus (dv) is a flavivirus carried by the aedes aegypti mosquito that causes a spectrum of illnesses in the tropics, including dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. dendritic cells (dcs) are professional antigen presenting cells recently shown to be permissive for dv, and implicated as the primary targets of initial dv infection. dv is transmitted to human host by infected mosquitoes during a blood meal, but it is currently unknown whether transmission is modi ...200415279703
effect of membrane curvature-modifying lipids on membrane fusion by tick-borne encephalitis virus.enveloped viruses enter cells by fusion of their own membrane with a cellular membrane. incorporation of inverted-cone-shaped lipids such as lysophosphatidylcholine (lpc) into the outer leaflet of target membranes has been shown previously to impair fusion mediated by class i viral fusion proteins, e.g., the influenza virus hemagglutinin. it has been suggested that these results provide evidence for the stalk-pore model of fusion, which involves a hemifusion intermediate (stalk) with highly bent ...200415280462
[densities of the tick (ixodes ricinus) and coexistence of the louping ill virus and tick borne encephalitis on the island of bornholm]. 200415285165
comparisons of physical separation methods of kunjin virus-induced membranes.the two sets of connected membranes induced in kunjin virus-infected cells are characterized by the presence of ns3 helicase/protease in both, and by rna-dependent rna polymerase (rdrp) activity plus the associated double-stranded rna (dsrna) template in vesicle packets (vp), or by the absence of both the vp-specific markers in the convoluted membranes/paracrystalline arrays (cm/pc). attempts were made to separate flavivirus-induced membranes by sedimentation or flotation analyses in density gra ...200415288961
arguments for live flavivirus vaccines. 200415302184
arguments for live flavivirus vaccines. 200415302187
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