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[transmission and conservation of the amaril virus in nature].the yellow fever virus is a monkey flavivirus transmitted by mosquitoes. the transmission cycles and vectors vary from western to eastern africa and in south america. there are two types of endemic areas where the virus is maintained: humid forests and emerging zones and areas where intermediary and urban epidemics occur. on both continents, the virus circulates in forest areas by moving epizooties from one region to another among non immune monkeys. the virus can also be maintained in an enzoot ...199911000958
identification of a flavivirus isolated from mosquitos in chiang mai thailand.a virus isolate, thcar105/92, from a pool of mosquitos, culex tritaeniorhynchus, collected in chiang mai, thailand in 1992, appeared to be a member of the genus flavivirus of the family flaviviridae, based on the reverse transcription polymerase chain reaction (rt-pcr) using flavivirus cross-reacting primer pairs, electron microscopic examination, and serological tests. however, rt-pcr using japanese encephalitis (je) virus-specific primers showed that the isolate was different from je virus. su ...199910695806
discovery of non-a, non-b hepatitis and identification of its etiology.the discovery of hepatitis c was the direct result of the landmark discoveries of hepatitis b virus (hbv) and hepatitis a virus (hav) and their serologies. screening tests for hav and hbv made it possible in the mid-1970s to examine cases of transfusion-associated hepatitis (tah) and to demonstrate that only approximately 25% resulted from hbv and that none were related to hav. consequently, approximately 75% of tah became classified as non-a, non-b hepatitis (nanbh). subsequently, chimpanzee st ...199910653450
infections with flaviviridae.the family of the flaviviridae contains 3 genera: (i) the hepaciviruses, to which belongs hepatitis c virus (hcv), (ii) the flaviviruses and (iii) the pestiviruses. over 140 million people, more than four times the number of hiv-positive individuals, are chronically infected with the hcv. hepatitis g virus (hgv) has not yet been assigned to a genus. the impact of this recently discovered virus is yet to be established. infections with flaviviruses such as yellow fever virus (yfv), dengue fever v ...199910655776
the ns5 gene location of two turkey meningoencephalitis virus genomic sequences.two new turkey meningoencephalitis virus (tmev) nucleotide sequences were aligned to complete sequences of genomes of the flaviviruses that were available at present in the genebank. it was found that the both tmev sequences represent different ns5 locations; the sequence with acc. no. af098456 is located downstream of that with acc. no. af013377 on the tmev ns5 gene. this finding provides further insight into the tmev ns5 gene structure and shows that the two sequences are located on the ns5 ge ...199910825933
[hepatitis c virus and resulting diseases].in 1989, the main agent causing non a non b hepatitis was identified as a rna virus of the flavivirus family, with several serotypes, and was denominated virus c. at the present moment, the knowledge about the infection features and diseases that it causes has expanded thanks to the availability of reliable laboratory techniques to detect the antibody and the virus. the prevalence of infection and the frequency of serotypes varies in different regions of the world. chile is a country with a low ...199910835742
[west nile virus: a migrating arbovirus of current interest].west nile (wn) virus is a common arbovirosis in sub-saharian africa. it has occasionally caused epidemics or epizootics in horses in mediterranean regions and southern europe. the virus is transmitted to humans by mosquitoes (primarily the culex species) that are infected by biting viremic birds. infections in humans are usually asymptomatic. recently, however, a growing number of cases involving central nervous system manifestations and deaths have been reported in elderly people in algeria and ...199910901852
mosquito feeding modulates th1 and th2 cytokines in flavivirus susceptible mice: an effect mimicked by injection of sialokinins, but not demonstrated in flavivirus resistant mice.culex pipiens and aedes aegypti mosquitoes were fed on c3h/hej mice and systemic cytokine production was quantified from stimulated lymphocytes harvested four to ten days after feeding. mosquito feeding on c3h/hej mice significantly down regulated ifn gamma production seven to ten days post feeding by cx. pipiens and seven days after ae aegypti feeding. th2 cytokines, il-4 and il-10, were significantly up regulated 4-7 days after cx. pipiens and ae. aegypti feeding. the immunosuppressive effect ...199910081770
genetic analysis of west nile new york 1999 encephalitis virus.analysis of the genome of the flavivirus responsible for the 1999 new york city encephalitis epidemic cloned from human brain by reverse-transcription polymerase chain reaction indicates its identity as a lineage i west nile virus (wnv; wnv-ny1999) closely related to wnvs previously isolated in the middle east.199910622305
viral heterogeneity of the hepatitis c virus.this review summarises the classification of hepatitis c virus as a flavivirus, the identification and detection of hcv genotypes, and reviews the current information concerning the geographical and risk group associations of the common genotypes in europe.199910622561
variations in lps responsiveness among different mouse substrains of c3h lineage and their congenic derivative sublines. 199910630301
tick-borne encephalitis virus ns3 gene expression does not protect mice from homologous viral challenge.tick-borne encephalitis virus (tbev) ns3 gene has been subcloned into the expression vector pcdnai and expressed in eukaryotic cells. immunization of mice with the recombinant plasmid pcdnai-ns3 induced antibodies against ns3 protein but did not protect from viral challenge.199910630787
[japanese encephalitis virus and other flavivirus]. 199910635838
isolation of homologous arbovirus cultures from heterologous mixtures using limit dilution and virus-specific enzyme immunoassays.viral cultures were identified recently that contained both kunjin virus and the closely related flavivirus west nile. the observation that the kun virus population grew more efficiently in a mosquito cell line (c6/36) while the wn population replicated more effectively in mammalian cells (vero) allowed enrichment for either virus by culturing the mixture in the appropriate cell line. limit dilution of the enriched virus preparations was then performed by infecting microtitre cultures with seria ...199910598096
origin of the west nile virus responsible for an outbreak of encephalitis in the northeastern united states.in late summer 1999, an outbreak of human encephalitis occurred in the northeastern united states that was concurrent with extensive mortality in crows (corvus species) as well as the deaths of several exotic birds at a zoological park in the same area. complete genome sequencing of a flavivirus isolated from the brain of a dead chilean flamingo (phoenicopterus chilensis), together with partial sequence analysis of envelope glycoprotein (e-glycoprotein) genes amplified from several other species ...199910600742
the ns3/4a proteinase of the hepatitis c virus: unravelling structure and function of an unusual enzyme and a prime target for antiviral therapy.the hepatitis c virus (hcv) is a major causative agent of transfusion-acquired and sporadic non-a, non-b hepatitis worldwide. infections most often persist and lead, in approximately 50% of all patients, to chronic liver disease. as is characteristic for a member of the family flaviviridae, hcv has a plus-strand rna genome encoding a polyprotein, which is cleaved co- and post-translationally into at least 10 different products. these cleavages are mediated, among others, by a virally encoded chy ...199910607229
flaviviridae polymerase and rna replication.sequence motifs within the non-structural protein ns5 or ns5b of the members of the family flaviviridae suggest that this protein is the rna-dependent rna polymerase. this protein has now been expressed in various in vitro systems and used in polymerase assays. to understand the role of the rna polymerase in rna replication, this review will examine not only the polymerase protein but also the other proteins in the rna replication complex. to date, several groups have investigated the interactio ...199910607240
hepatitis g: viroprevalence and seroconversion in a high-risk group of children.hepatitis g virus (hgv), a recently discovered flavivirus, is parenterally transmitted and significantly associated with hepatitis c viraemia. data on the viroprevalence of this agent in children is scant and its seroprevalence is unknown. the aim of this study was to determine the viroprevalence and seroprevalence of hgv in paediatric patients at risk of parenterally transmitted virus infection. sera from 35 patients, previously tested for hepatitis c virus (hcv) infection, were analysed for th ...199910607249
evaluation of an igg enzyme-linked immunosorbent assay for dengue diagnosis.the hemagglutination inhibition (hi) test has been one of the standards, with the igm antibody capture elisa (mac-elisa), for the diagnosis of dengue virus infections. the spread of dengue throughout the world and the increasing number of cases to be tested makes an elisa-format test for igg antibodies to replace the hi test highly desirable.199910614855
mosquito-borne viruses in western europe: a review.several mosquito-borne arboviruses belonging to the genera alphavirus, flavivirus, and bunyavirus have been reported to occur in mosquitoes and to infect humans and other vertebrates in western europe. these zoonotic viruses circulate in nature either in an aedes-mammal, anopheles-mammal, or culex-bird transmission cycle. infected humans normally do not contribute to the virus circulation. west nile virus (flavivirus) caused an outbreak of fever, malaise, pain in eyes and muscles, and headache a ...199910436876
genetic interaction of flavivirus nonstructural proteins ns1 and ns4a as a determinant of replicase function.nonstructural protein 1 (ns1) of yellow fever virus (yf) is a glycoprotein localized to extracytoplasmic compartments within infected cells. we have previously shown that ns1 can be supplied in trans and is required for viral rna replication, a process thought to occur in membrane-bound cytoplasmic complexes. here we report that the ns1 gene from a related virus, dengue virus (den), is unable to function in the process of yf rna replication. this virus-specific incompatibility leads to a lack of ...199910233920
mutation patterns for two flaviviruses: hepatitis c virus and gb virus c/hepatitis g virus.we studied the mutation patterns of hepatitis c virus (hcv) and gb virus c/hepatitis g virus (hgv). although the mutation patterns of the two viruses were similar to each other, they were quite different from that of hiv. in particular, the similarity of the patterns between hcv or hgv and human nuclear pseudogenes was statistically significant whereas there was no similarity between hiv and human nuclear pseudogenes. this finding suggests that the mutation patterns of hcv and hgv are similar to ...199910359092
the anamnestic neutralizing antibody response is critical for protection of mice from challenge following vaccination with a plasmid encoding the japanese encephalitis virus premembrane and envelope genes.for japanese encephalitis (je), we previously reported that recombinant vaccine-induced protection from disease does not prevent challenge virus replication in mice. moreover, dna vaccines for je can provide protection from high challenge doses in the absence of detectable prechallenge neutralizing antibodies. in the present study, we evaluated the role of postchallenge immune responses in determining the outcome of je virus infection, using mice immunized with a plasmid, pcdna3jeme, encoding th ...199910364301
mapping of functional elements in the stem-anchor region of tick-borne encephalitis virus envelope protein e.envelope protein e of the flavivirus tick-borne encephalitis virus mediates membrane fusion, and the structure of the n-terminal 80% of this 496-amino-acid-long protein has been shown to differ significantly from that of other viral fusion proteins. the structure of the carboxy-terminal 20%, the stem-anchor region, is not known. it contains sequences that are important for membrane anchoring, interactions with prm (the precursor of membrane protein m) during virion assembly, and low-ph-induced s ...199910364309
molecular evidence of mother-to-infant transmission of hepatitis g virus among women without known risk factors for parenteral infections.hepatitis g virus (hgv) rna was detected in 18 of 133 pregnant women from tanzania without known risk factors for hgv infection and in 7 of 18 children born to hgv rna-positive mothers. molecular evidence of mother-to-infant transmission was obtained only for three of seven children. hgv rna was also detected in 4 of 42 children born to non-hgv-infected women. thus, mechanisms other than materno-filial may play an important role in hgv transmission during early childhood.199910364608
degradation of japanese encephalitis virus by neutrophils.the ability of neutrophils to degrade the phagocytosed japanese encephalitis (je) virion, via triggering of the respiratory burst and generation of toxic radicals has been investigated. jev or jev-induced macrophage derived factor (mdf) induces increase in intracellular oxidative signals with generation of superoxide anion (o2-), via activation of cytosolic nadph and subsequent formation of hydrogen peroxide, with maximum activity on day 7 post infection. the response was sensitive to anti-mdf a ...199910365083
partial nucleotide sequencing of the ns3/helicase region of hepatitis g virus to prove vertical transmission.to study non-parental transmission of hepatitis g virus and/or gb virus c (hgv/gbv-c), we sequenced and compared the ns3/helicase region of the virus for five hgv/gbv-c rna-positive mothers and their 11 children who had experienced neither blood transfusion nor overt hepatitis and were negative for hbv, hcv and hiv, except in one mother coinfected with hcv. the nucleotide sequences of the familial hgv/gbv-c isolates showed high similarity of 99-100% (mean 99.8%, 100% at the deduced amino acid le ...199910386379
crystallization, characterization and measurement of mad data on crystals of dengue virus ns3 serine protease complexed with mung-bean bowman-birk inhibitor.crystallization and preliminary characterization of the essential dengue virus ns3 serine protease complexed with a bowman-birk-type inhibitor from mung beans are reported. as the structure proved resistant to solution by molecular replacement and multiple isomorphous replacement methods, multi-wavelength anomalous diffraction data at the liii edge of a holmium derivative have been measured. promising bijvoet and dispersive signals which are largely consistent with expected values have been extr ...199910393310
membrane permeabilization by small hydrophobic nonstructural proteins of japanese encephalitis virus.infection with japanese encephalitis virus (jev), a mosquito-borne flavivirus, may cause acute encephalitis in humans and induce severe cytopathic effects in various types of cultured cells. we observed that jev replication rendered infected baby hamster kidney (bhk-21) cells sensitive to the translational inhibitor hygromycin b or alpha-sarcine, to which mock-infected cells were insensitive. however, little is known about whether any jev nonstructural (ns) proteins contribute to virus-induced c ...199910400716
functional analysis of cell surface-expressed hepatitis c virus e2 glycoprotein.hepatitis c virus (hcv) glycoproteins e1 and e2, when expressed in eukaryotic cells, are retained in the endoplasmic reticulum (er). c-terminal truncation of e2 at residue 661 or 715 (position on the polyprotein) leads to secretion, consistent with deletion of a proposed hydrophobic transmembrane anchor sequence. we demonstrate cell surface expression of a chimeric glycoprotein consisting of e2 residues 384 to 661 fused to the transmembrane and cytoplasmic domains of influenza a virus hemaggluti ...199910400776
a monoclonal antibody that recognizes the predicted tick-borne encephalitis virus e protein fusion sequence blocks fusion.the fusion motif of tick-borne encephalitis virus e protein has been predicted to be located within its conserved region (98-120). results are presented to demonstrate that non-neutralizing monoclonal antibody which recognizes a synthetic peptide corresponding to residues 98-113 of the e protein sequence can block the fusion of the virus particles with artificial membranes.199910416385
communicable diseases surveillance. you left an error in the record. 199910432763
rapid serologic diagnosis of dengue virus infection using a commercial capture elisa that distinguishes primary and secondary infections.a commercial capture elisa for specific igm and igg antibodies produced during dengue infection (panbio dengue duo) showed excellent sensitivity (99%, n = 78) using sera collected at hospital discharge compared with established elisa and hemagglutination inhibition (hai) assays. furthermore, the elisa was able to diagnose 79% of the dengue cases using sera collected at hospital admission. the elisa also showed high specificity (92%) in paired sera from patients without flavivirus infection (n = ...199910348250
mutational analysis of bovine viral diarrhea virus rna-dependent rna polymerase.recombinant bovine viral diarrhea virus (bvdv) nonstructural protein 5b (ns5b) produced in insect cells has been shown to possess an rna-dependent rna polymerase (rdrp) activity. our initial attempt to produce the full-length bvdv ns5b with a c-terminal hexahistidine tag in escherichia coli failed due to the expression of insoluble products. prompted by a recent report that removal of the c-terminal hydrophobic domain significantly improved the solubility of hepatitis c virus (hcv) ns5b, we cons ...199910559328
screening of protective antigens of japanese encephalitis virus by dna immunization: a comparative study with conventional viral vaccines.in this study, we evaluated the relative role of the structural and nonstructural proteins of the japanese encephalitis virus (jev) in inducing protective immunities and compared the results with those induced by the inactivated jev vaccine. several inbred and outbred mouse strains immunized with a plasmid (pe) encoding the jev envelope protein elicited a high level of protection against a lethal jev challenge similar to that achieved by the inactivated vaccine, whereas all the other genes teste ...199910559329
efficient trans-complementation of the flavivirus kunjin ns5 protein but not of the ns1 protein requires its coexpression with other components of the viral replicase.successful trans-complementation of the defective kunjin virus (kun) rna fldgdd with a deletion of the rna polymerase motif gdd in the ns5 gene by using a bhk cell line, repbhk, that continuously produced a functionally active kun replication complex (rc) from replicon rna was recently reported (a. a. khromykh, m. t. kenney, and e. g. westaway, j. virol. 72:7270-7279, 1998). in order to identify whether this complementation of fldgdd rna was provided by the wild-type ns5 protein alone or with th ...199910559344
prevalence of gbv-c/hgv-rna, virus genotypes, and anti-e2 antibodies in autoimmune hepatitis.we investigated the prevalence of hepatitis g-rna (gbv-c/hgv-rna), a recently cloned new flavivirus, and of antibodies to the envelope 2 antigen (anti-e2), a marker of past infection, in patients with autoimmune hepatitis, and compared it with the prevalence in patients with chronic viral hepatitis and healthy control individuals.199910566740
characterization of infectious murray valley encephalitis virus derived from a stably cloned genome-length cdna.an infectious cdna clone of murray valley encephalitis virus prototype strain 1-51 (mve-1-51) was constructed by stably inserting genome-length cdna into the low-copy-number plasmid vector pmc18. designated pmve-1-51, the clone consisted of genome-length cdna of mve-1-51 under the control of a t7 rna polymerase promoter. the clone was constructed by using existing components of a cdna library, in addition to cdna of the 3' terminus derived by rt-pcr of poly(a)-tailed viral rna. upon comparison w ...199910567642
phylogenetic and virulence analysis of tick-borne encephalitis viruses from japan and far-eastern russia.we have previously reported that tick-borne encephalitis (tbe) is endemic in a specific area of hokkaido, japan. in oshima, the southern part of hokkaido, tbe virus was isolated from sentinel dogs, ticks and rodents in 1995 and 1996. to identify when these tbe viruses emerged in hokkaido, the times of divergence of tbe virus strains isolated in oshima and far-eastern russia were estimated. tbe virus was isolated in khabarovsk in 1998 and the nucleotide sequences of viral envelope protein genes o ...199910567643
the rna-dependent rna polymerases of different members of the family flaviviridae exhibit similar properties in vitro.the virus-encoded rna-dependent rna polymerase (rdrp), which is required for replication of the positive-strand rna genome, is a key enzyme of members of the virus family flaviviridae. by using heterologously expressed proteins, we demonstrate that the 77 kda ns5b protein of two pestiviruses, bovine viral diarrhoea virus and classical swine fever virus, and the 100 kda ns5 protein of the west nile flavivirus possess rdrp activity in vitro. as originally shown for the rdrp of hepatitis c virus, r ...199910573150
the design and synthesis of potent inhibitors of hepatitis c virus ns3-4a proteinase.hepatitis c virus (hcv) is the cause of the majority of transfusion-associated hepatitis and a significant proportion of community-acquired hepatitis worldwide. infection by hcv frequently leads to persistent infections that result in a range of clinical conditions including an asymptomatic carrier state, severe chronic active hepatitis, cirrhosis and, in some cases, hepatocellular carcinoma. the hcv genome consists of a single-stranded, positive sense rna containing an open reading frame of app ...199910574181
a dna immunization model study with constructs expressing the tick-borne encephalitis virus envelope protein e in different physical forms.we have conducted a dna immunization study to evaluate how the immune response is influenced by the physical structure and secretion of the expressed ag. for this purpose, we used a series of plasmid constructs encoding different forms of the envelope glycoprotein e of the flavivirus tick-borne encephalitis virus. these included a secreted recombinant subviral particle, a secreted carboxyl-terminally truncated soluble homodimer, a nonsecreted full-length form, and an inefficiently secreted trunc ...199910586074
recombinant semliki forest virus particles encoding the prme or ns1 proteins of louping ill virus protect mice from lethal challenge.recombinant semliki forest virus (rsfv) vaccines encoding louping ill virus (liv) genes prme and ns1 were examined. cells transfected with rsfv-prme rna showed correct processing of the precursor prme and the release into the medium of m and e proteins in particulate form, whilst rsfv-ns1-transfected cells secreted glycosylated, heat-labile ns1 dimers. mice immunized with rsfv particles produced antibodies against prme and ns1 that were mainly of the igg2a subtype, indicating that a t-helper 1 i ...199910355766
preliminary studies on the use of solid-phase immunosorbent techniques for the rapid detection of wesselsbron virus (wslv) igm by haemagglutination-inhibition.serum samples from 446 randomly selected persons belonging to different age groups and locations in nigeria were tested for the presence of wslv igm using the flavivirus haemagglutination-inhibition (hi) test adopted to the solid-phase immunosorbent technique (spit). 61 (14%) persons had igm to wslv only, while 9 (2%) persons had heterologous igm to wslv and two other flaviviruses, namely yellow fever and uganda s viruses. there was a high prevalence of igm in people of younger age groups than t ...199910099030
homology model of the dengue 2 virus ns3 protease: putative interactions with both substrate and ns2b cofactor.the crystal structure coordinates of the hepatitis c virus ns3 protease (hcvpro) were used to develop an homology model of the dengue 2 virus ns3 protease (den2pro). the amino acid sequence of den2pro accommodates the same alpha-helices, beta-sheets and protein-binding domains as its hcvpro counterpart, but the model predicts a number of significant differences for den2pro and its interactions with substrates and cofactor. whereas hcvpro contains a zn2+-binding site, there is no equivalent metal ...199910355763
analysis of murine cd8(+) t-cell clones specific for the dengue virus ns3 protein: flavivirus cross-reactivity and influence of infecting serotype.serotype-cross-reactive dengue virus-specific cytotoxic t lymphocytes (ctl) induced during a primary dengue virus infection are thought to play a role in the immunopathogenesis of dengue hemorrhagic fever (dhf) during a secondary dengue virus infection. although there is no animal model of dhf, we previously reported that murine dengue virus-specific ctl responses are qualitatively similar to human dengue virus-specific ctl responses. we used balb/c mice to study the specificity of the ctl respo ...19999847344
identification and analysis of truncated and elongated species of the flavivirus ns1 protein.the flavivirus non-structural glycoprotein ns1 is often detected in western blots as a heterogeneous cluster of bands due to glycosylation variations, precursor-product relationships and/or alternative cleavage sites in the viral polyprotein. in this study, we determined the basis of structural heterogeneity of the ns1 protein of murray valley encephalitis virus (mve) by glycosylation analysis, pulse-chase experiments and terminal amino acid sequencing. inhibition of n-linked glycosylation by tu ...199910225275
[a study on the pathogenicity of acute hepatitis g infection].to study the infection due to hepatitis g virus (hgv) in liver tissues of patients with acute hepatitis and to investigate its pathogenicity.199911798655
[expression of non-structural region 3 gene of the chinese hgy and analysis of the antigenicity of the recombinant proteins].this study is to analyze the antigenicity of the ns3 proteins of chinese hgv and their potential use in the serological diagnosis.199912569774
[a study of hgv infection in liver tissue of hepatocellular carcinoma].to investigate the prevalence of hepatitis g virus (hgv) in hepatocellular carcinoma (hcc).199912569791
hepatitis g virus (hgv) and liver diseases.recently, a new flavi-like virus, provisionally named hepatitis gbv-c or hepatitis g virus (hgv), has been described and was initially thought to be the major etiological agent of non-a-e hepatitis. hgv does not induce an immune response that is consistently detectable by using recombinant proteins from prokaryotic expression and hence prevalence studies have been conducted by using polymerase chain reaction (pcr)-based system. hgv-rna has been detected in many human populations. this article re ...199919864743
use of the vaccinia virus/t7 expression system for studying hcv protein processing.hcv and related viruses are now classified as a separate genus in the family flaviviridae (1), which includes two other genera, flavivirus (2), and pestivirus (3). the positive-strand hcv genome rna is approx 9.4 kb in length and contains a highly conserved 5' noncoding region followed by a long open reading frame encoding a polyprotein of 3010-3033 amino acids (4,5) recently, it was determined that the 3' end contains another highly conserved noncoding region approx 100 bp in length (6-8). beca ...199921374371
diagnosis of turkey meningoencephalitis virus infection in field cases by rt-pcr compared to virus isolation in embryonated eggs and suckling mice.turkey meningoencephalitis (tme) is a paralytic epornitic disease of turkeys caused by turkey meningoencephalitis virus (tmev), an arthopod-borne flavivirus belonging to the ntaya serogroup vi. a tmev specific rt-pcr was compared with classical techniques for tmev diagnosis, which include virus isolation in 8-day-old chicken embryonated eggs and suckling mice, on 17 tme flocks with neurological signs that occurred during the fall of 1997. in 11/17 flocks both the rt-pcr and the virus isolation m ...200019184786
[hepatitis c virus infection mimicking hemorrhagic fever: a case report]acute c hepatitis, compared with hepatitis a or b, may sometimes be associated with extrahepatic manifestations of a haematologic nature. the first case of hepatitis associated with aplastic anemia was reported by lorenz in 1955. we observed a patient who developed acute hepatitis, associated with febrile purpura: pancytopenia was present, but not aplasia. this association is frequent in flavivirus-related infections, like dengue and yellow fever, and principally affects children and young peopl ...200012714845
distribution of dengue and japanese encephalitis among children in rural and suburban thai villages.in the rainy season of 1989, igg and igm antibodies against dengue and japanese encephalitis viruses (measured by enzyme-linked immunoassay [elisa]) in serum from all primary-school children in two areas of central thailand were sampled in order to choose a study site for more detailed epidemiological and entomological analysis. students in three schools in the largely non-agricultural, suburban community of bang bua thong, nontaburi province were sampled in late june and july. of 1,477 children ...200011357991
enzootic transmission of deer tick virus in new england and wisconsin sites.to determine whether rodents that are intensely exposed to the deer tick-transmitted agents of lyme disease, human granulocytic ehrlichiosis, and human babesiosis are also exposed to deer tick virus (dtv), we assayed serum samples from white-footed mice (peromyscus leucopus) and meadow voles (microtus pennsylvanicus) in sites densely infested by deer ticks. to conduct serosurveys, we developed an enzyme-linked immunosorbent assay (elisa) and western blot assay by cloning, expressing, and purifyi ...200011357992
encephalitis and retarded growth of chicks caused by sitiawan virus, a new isolate belonging to the genus flavivirus.a new virus named sitiawan virus (sv) was isolated from sick broiler chicks in chicken embryos. the virus replicated well with cytopathogenic effect (cpe) in the chicken b-lymphocyte cell line lscc-bk3. the virus was an enveloped rna virus of approximately 41 nm in size with hemagglutinating activity (ha) to goose erythrocytes. it was cross-reactive with japanese encephalitis virus (jev), a member of flaviviruses by ha inhibition tests but not by cross-virus neutralization tests. the cdna fragme ...200011358004
west nile viral encephalitis.west nile virus (wnv) has emerged in recent years in temperate regions of europe and north america, presenting a threat to both public and animal health. the most serious manifestation of infection is fatal encephalitis in humans and horses, as well as mortality in certain domestic and wild birds. a recent development in the epizootiology of this mosquito-borne flavivirus was the occurrence of a severe outbreak in new york city and surrounding areas. during this outbreak, mortality was observed ...200011189714
west nile virus investigations in south moravia, czechland.seven virus isolates were obtained from 11,334 mosquitoes after the 1997 morava river flooding in south moravia (czech republic): 6 strains of tahyna bunyavirus, california antigenic group (5 from aedes vexans, 1 from ae. cinereus), and 1 strain of west nile flavivirus (wnv) from culex pipiens. in 1999, one isolate of tahyna virus from ae. vexans and one isolate of wnv from cx. pipiens were recovered from a total of 14,354 mosquitoes examined in the same area, whereas no virus was detected there ...200011192289
west nile encephalitis.wnv encephalitis in horses, previously reported in africa, asia, and europe, occurred for the first time in the western hemisphere in 1999. the causative agent, wnv, is a flavivirus maintained in nature by a bird-mosquito cycle. the disease in horses is manifested primarily by ataxia of variable severity. outbreaks of encephalitis may have a case fatality rate in excess of 40%, although this virus infection is inapparent in some horses. early evidence indicates that wnv has overwintered in the n ...200011219341
japanese encephalitis.japanese encephalitis (je) virus is a mosquito-borne flavivirus that can cause encephalitis and death in horses and humans. it is an emerging disease of international concern because it has been spreading into previously nonendemic areas. major epidemics may occur where the virus moves into new areas, but many infections are subclinical. this article presents information on the virus, its epidemiology, and what little information has been published on the disease in horses. the methods available ...200011219350
genetic variation of japanese encephalitis virus in taiwan.a 280-nucleotide sequence from the capsid-premembrane (c/prem) gene region of 44 japanese encephalitis (je) virus strains isolated in taiwan from mosquitoes from 1983 to 1994, and 3 strains, (ling [1965], chang [1965], and hv1 [1958]) isolated from human brain were analyzed by direct sequencing of reverse transcription-polymerase chain reaction (rt-pcr) amplified products and compared with the corresponding sequences of reference strains. the overall sequence homology of the 47 isolates was > or ...200011220759
replicon-based vectors of positive strand rna viruses.vectors based on self-replicating rnas (replicons) of positive strand rna viruses are becoming powerful tools for gene expression in mammalian cells and for the development of novel antiviral and anticancer vaccines. a relatively small genome size and simple procedure allow rapid generation of recombinants. cytoplasmic rna amplification eliminates nuclear involvement and leads to extremely high levels of gene expression, and continuous synthesis of double stranded rna results in induction of enh ...200011249758
production of active mammalian and viral proteases in bacterial expression systems. 200011255667
isolation of japanese encephalitis virus from mosquitoes (diptera: culicidae) collected in the western province of papua new guinea, 1997-1998.after japanese encephalitis (je) virus emerged in the torres strait in australia in 1995, investigations were initiated into the origin of the incursion. new guinea was considered the most likely source, given its proximity to islands of the torres strait. almost 400,000 adult mosquitoes were processed for virus isolation from 26 locations in the western province of papua new guinea (png) between february 1996 and february 1998, yielding three isolates of je virus. two isolates of murray valley ...200011289676
dengue virus specific t cell responses to live attenuated monovalent dengue-2 and tetravalent dengue vaccines.the proliferative t cell responses to dengue vaccines were studied using the parental strains of dengue vaccines as antigens in 26 dengue immune individuals who resided in bangkok which is the endemic area of dengue infection. the magnitude of the t cell responses in subjects with flavivirus cross-reactive neutralizing antibody was much higher and the cross-reactivity was broader than in those with dengue serotype-specific neutralizing antibodies, japanese encephalitis (je) specific antibodies o ...200011316044
mutagenesis of the signal sequence of yellow fever virus prm protein: enhancement of signalase cleavage in vitro is lethal for virus production.proteolytic processing at the c-prm junction in the flavivirus polyprotein involves coordinated cleavages at the cytoplasmic and luminal sides of an internal signal sequence. we have introduced at the cooh terminus of the yellow fever virus (yfv) prm signal sequence amino acid substitutions (vpqaqa mutation) which uncoupled efficient signal peptidase cleavage of the prm protein from its dependence on prior cleavage in the cytoplasm of the c protein mediated by the viral ns2b-3 protease. infectiv ...200010590087
identification and characterization of the rna helicase activity of japanese encephalitis virus ns3 protein.the ns3 protein of japanese encephalitis virus (jev) contains motifs typical of rna helicase/ntpase but no rna helicase activity has been reported for this protein. to identify and characterize the rna helicase activity of jev ns3, a truncated form of the protein with a his-tag was expressed in escherichia coli and purified. the purified jev ns3 protein showed an rna helicase activity, which was dependent on divalent cations and atp. an asp-285-to-ala substitution in motif ii of the jev ns3 prot ...200010620709
rna viruses: emerging vectors for vaccination and gene therapy.the application of modern molecular techniques has profoundly influenced our understanding of virus function. as a consequence, virus biology is being directly applied to medical research. it is a reflection of the current pace of virology that we are now beginning to think of our ancient foes as useful and beneficial tools.200010637572
chimeric yellow fever virus 17d-japanese encephalitis virus vaccine: dose-response effectiveness and extended safety testing in rhesus monkeys.chimerivax-je is a live, attenuated recombinant virus prepared by replacing the genes encoding two structural proteins (prm and e) of yellow fever 17d virus with the corresponding genes of an attenuated strain of japanese encephalitis virus (je), sa14-14-2 (t. j. chambers et al., j. virol. 73:3095-3101, 1999). since the prm and e proteins contain antigens conferring protective humoral and cellular immunity, the immune response to vaccination is directed principally at je. the prm-e genome sequen ...200010644345
mutational analysis of the gb virus b internal ribosome entry site.gb virus b (gbv-b) is a recently discovered hepatotropic flavivirus that is distantly related to hepatitis c virus (hcv). we show here that translation of its polyprotein is initiated by internal entry of ribosomes on gbv-b rna. we analyzed the translational activity of dicistronic rna transcripts containing wild-type or mutated 5' nontranslated gbv-b rna (5'ntr) segments, placed between the coding sequences of two reporter proteins, in vitro in rabbit reticulocyte lysate and in vivo in transfec ...200010623739
prevalence of hepatitis g virus in patients with hemophilia and their steady female sexual partners.hepatitis g virus (hgv), also known as gb virus c, is a newly discovered flavivirus that is transmissible by blood transfusion and other possible routes.200010726654
cross-genotypic interaction between hepatitis c virus ns3 protease domains and ns4a cofactors.hepatitis c virus (hcv) nonstructural protein 3 (ns3) protease requires ns4a as a cofactor. this cofactor activity has been mapped to the central region of ns4a which interacts with the n-terminus of ns3 protease. to investigate whether this interaction is conserved among different genotypes of hcv cross-genotypic characterization were performed to delineate the importance of ns4a cofactor function in relation to the molecular evolution of hcv methods: active ns3 protease domains of genotype 1-3 ...200010735621
early diagnosis of murray valley encephalitis by reverse transcriptase-polymerase chain reaction.a 4-year-old aboriginal boy developed encephalitis due to murray valley encephalitis virus (mve) following an earlier infection with kunjin virus (kun). the illness was severe, resulting in cerebral atrophy and profound physical and intellectual disability. the earlier kun infection complicated his serological profile and delayed antibody responses to mve. by contrast, the reverse transcriptase-polymerase chain reaction (rt-pcr) assay detected mve in serum 3 days after the onset of illness and 4 ...200010740807
purified ns2b/ns3 serine protease of dengue virus type 2 exhibits cofactor ns2b dependence for cleavage of substrates with dibasic amino acids in vitro.dengue virus type 2 ns3, a multifunctional protein, has a serine protease domain (ns3pro) that requires the conserved hydrophilic domain of ns2b for protease activity in cleavage of the polyprotein precursor at sites following two basic amino acids. in this study, we report the expression of the ns2b-ns3pro precursor in escherichia coli as a fusion protein with a histidine tag at the n terminus. the precursor was purified from insoluble inclusion bodies by ni(2+) affinity and gel filtration chro ...200010744671
evidence that the gbv-c/hepatitis g virus is primarily a lymphotropic virus.gb virus-c and the hepatitis g virus (gbv-c/hgv) are variants of the same positive sense rna flavivirus, initially thought to be associated with hepatitis. the tissue tropism of gbv-c/hgv in normal subjects has not been evaluated to date using an extended tissue spectrum. therefore, the sites of gbv-c/hgv replication were investigated in serum and twenty-three tissues collected during post-mortem examination of four apparently healthy individuals who died accidental deaths, who were infected wit ...200010745232
a single intramuscular injection of recombinant plasmid dna induces protective immunity and prevents japanese encephalitis in mice.plasmid vectors containing japanese encephalitis virus (jev) premembrane (prm) and envelope (e) genes were constructed that expressed prm and e proteins under the control of a cytomegalovirus immediate-early gene promoter. cos-1 cells transformed with this plasmid vector (je-4b clone) secreted jev-specific extracellular particles (eps) into the culture media. groups of outbred icr mice were given one or two doses of recombinant plasmid dna or two doses of the commercial vaccine jevax. all mice t ...200010756038
virus-specific cofactor requirement and chimeric hepatitis c virus/gb virus b nonstructural protein 3.gb virus b (gbv-b) is closely related to hepatitis c virus (hcv) and causes acute hepatitis in tamarins (saguinus species), making it an attractive surrogate virus for in vivo testing of anti-hcv inhibitors in a small monkey model. it has been reported that the nonstructural protein 3 (ns3) serine protease of gbv-b shares similar substrate specificity with its counterpart in hcv. authentic proteolytic processing of the hcv polyprotein junctions (ns4a/4b, ns4b/5a, and ns5a/5b) can be accomplished ...200010756044
stable high-level expression of heterologous genes in vitro and in vivo by noncytopathic dna-based kunjin virus replicon vectors.primary features of the flavivirus kunjin (kun) subgenomic replicons include continuous noncytopathic replication in host cell cytoplasm and the ability to be encapsidated into secreted virus-like particles (vlps). previously we reported preparation of rna-based kun replicon vectors and expression of heterologous genes (hg) in cell culture after rna transfection or after infection with recombinant kun vlps (a. n. varnavski and a. a. khromykh, virology 255:366-375, 1999). in this study we describ ...200010756054
[west nile fever].reviews the data on the history, distribution, ecology, epidemiology, and clinical picture of west nile (wn) fever and the ecology of the virus (flaviviridae, flavivirus, japanese encephalitis complex). analyzes the causes of sudden epidemic outbreaks with high mortality in rumania in 1996, in european southern russia, and in new york and its environs in 1999. offers recommendations on decreasing the damage inflicted by new and emerging infections leading to epidemic emergencies.200010765542
construction of a full length infectious clone for dengue-1 virus western pacific,74 strain.the flavivirus dengue 1 western pacific,74 (den1 wp) virus has a positive-stranded rna genome of 10,735 nucleotides. den1 wp genomic rna was amplified into three overlapping fragments by rt-pcr. these fragments were assembled into a full-length cdna clone in the yeast-e. coli shuttle vector prs424, using homologous recombination in yeast. rna produced by in vitro transcription of this clone was infectious upon electroporation into llcmk2 cells, as shown by cytopathic effects and detection of vir ...200010766307
phylogenetic comparison of the den-2 mexican isolate with other flaviviruses.recent attention has focused on the geographic variation of dengue viruses, since major epidemies may follow introduction of a new virus strain into susceptible populations. we cloned and sequenced a very interesting mexican isolate (200787/1983) which is antigenically unique by signature analysis with respect to all other dengue-2 topotype viruses. this strain is also unique in biological behavior (neurotropism) and is of epidemiological significance in mexico. the dengue-2 mexican isolate sequ ...200010773737
[what are the indications in france for vaccination against japanese encephalitis?].japanese encephalitis is a mosquito-borne viral disease occurring in rural and rice-growing areas of asia, where mosquitoes proliferate, transmitting the flavivirus from viremic animals, mostly pigs, to humans. japanese encephalitis has recently spread to previously non-affected regions, leading to serious outbreaks among non-immune populations. although it has a high proportion of unsymptomatic infection, clinical encephalitis is usually severe, resulting in a very high mortality rate, and neur ...200010774494
severity-related molecular differences among nineteen strains of dengue type 2 viruses.comparative nucleotide sequencing was carried out on dengue type 2 virus (den-2) strains isolated from patients in northeast thailand during the epidemic season in 1993. the patients exhibited different clinical manifestations ranging from dengue fever (df) to dengue haemorrhagic fever (dhf)/dengue shock syndrome (dss). the results classified 19 den-2 strains into 3 subtypes according to nonsynonymous amino acid replacements. the strain isolated from a dss patient eliciting secondary serological ...200010789505
detection of anti-arboviral immunoglobulin g by using a monoclonal antibody-based capture enzyme-linked immunosorbent assay.monoclonal antibody (mab)-based capture enzyme-linked immunosorbent assays (elisas) for the detection of anti-arboviral immunoglobulin g (igg elisas) were developed for a comprehensive array of medically important arboviruses from the alphavirus, flavivirus, and bunyavirus genera. tests were optimized and standardized so that maximum homology could be maintained among working parameters for the different viral agents, enabling a wide range of viruses to be easily tested for at one time. mabs wer ...200010790108
codon-substitution models for heterogeneous selection pressure at amino acid sites.comparison of relative fixation rates of synonymous (silent) and nonsynonymous (amino acid-altering) mutations provides a means for understanding the mechanisms of molecular sequence evolution. the nonsynonymous/synonymous rate ratio (omega = d(n)d(s)) is an important indicator of selective pressure at the protein level, with omega = 1 meaning neutral mutations, omega < 1 purifying selection, and omega > 1 diversifying positive selection. amino acid sites in a protein are expected to be under di ...200010790415
definition of an epitope on japanese encephalitis virus (jev) envelope protein recognized by jev-specific murine cd8+ cytotoxic t lymphocytes.we defined an epitope on the japanese encephalitis virus (jev) envelope (e) protein recognized by cd8+ cytotoxic t lymphocytes (ctls). ctls induced in jev-infected balb/c (h-2d) mice recognized e and/or premembrane (prm) proteins, while ctls in c57bl/6j (h-2b) and c3h/hej (h-2k) mice did not. jev-specific ctls had a phenotype of cd3+ cd4- cd8+. twenty-four 9-amino acid (a.a.) peptides, which had binding motifs for h-2kd, h-2ld or h-2dd, were synthesized according to the amino acid sequences of p ...200010795519
immunisation with gamma globulin to murray valley encephalitis virus and with an inactivated japanese encephalitis virus vaccine as prophylaxis against australian encephalitis: evaluation in a mouse model.in northwestern australia, the flavivirus murray valley encephalitis (mve) poses a significant health risk to infants in some aboriginal communities, particularly during each wet season. while there are too few cases to warrant the development of a vaccine against mve, a safe, effective prophylaxis for these children is still urgently required. the use of passive transfer of human gamma globulin to mve or immunisation with a vaccine to the closely related japanese encephalitis (je) virus were in ...200010797383
first field evidence for natural vertical transmission of west nile virus in culex univittatus complex mosquitoes from rift valley province, kenya.west nile virus is a mosquito borne flavivirus endemic over a large geographic area including africa, asia, and the middle east. although the virus generally causes a mild, self-limiting febrile illness in humans, it has sporadically caused central nervous system infections during epidemics. an isolate of west nile virus was obtained from a pool of four male culex univittatus complex mosquitoes while we were conducting an investigation of rift valley fever along the kenya-uganda border in februa ...200010813479
gb virus-c/hepatitis g virus infection in a hepatitis c virus endemic village: prevalence in residents with low educational attainment and frequent recovery in females.gb virus-c/hepatitis g virus (hgv) is a newly identified flavivirus, which may share the same mode of transmission as hepatitis c virus (hcv). the aim of this study was to investigate associated factors of hgv infection and clearance in a hcv endemic village in southern taiwan.200010902972
migratory birds and spread of west nile virus in the western hemisphere.west nile virus, an old world flavivirus related to st. louis encephalitis virus, was first recorded in the new world during august 1999 in the borough of queens, new york city. through october 1999, 62 patients, 7 of whom died, had confirmed infections with the virus. ornithophilic mosquitoes are the principal vectors of west nile virus in the old world, and birds of several species, chiefly migrants, appear to be the major introductory or amplifying hosts. if transovarial transmission or survi ...200010905964
isolation of two strains of west nile virus during an outbreak in southern russia, 1999.from july to september 1999, a widespread outbreak of meningoencephalitis associated with west nile virus (flavivirus, flaviviridae) occurred in southern russia, with hundreds of cases and dozens of deaths. two strains of west nile virus isolated from patient serum and brain-tissue samples reacted in hemagglutination-inhibition and neutralization tests with patients' convalescent-phase sera and immune ascites fluid from other strains of west nile virus.200010905970
solid phase synthesis of aminoboronic acids: potent inhibitors of the hepatitis c virus ns3 proteinase.use of a resin bound diol as a boronic acid protecting group has been developed to allow the parallel synthesis of potent inhibitors of the hepatitis c virus ns3 serine proteinase.200010915055
role of the dexh motif of the japanese encephalitis virus and hepatitis c virus ns3 proteins in the atpase and rna helicase activities.the role of the conserved dexh motif of the japanese encephalitis virus (jev) ns3 protein in the atpase and rna helicase activities was compared with that of the hepatitis c virus (hcv) ns3 protein. in the dexh motif of jev ns3, asp-285 and glu-286 were essential for both atpase and rna helicase activities. cys-287 was critical for the rna helicase activity of jev ns3 but not for atpase activity. a his-288-to-ala substitution in the dexh motif of hcv ns3 resulted in an increase in atpase activit ...200010915602
ns3 serine protease of bovine viral diarrhea virus: characterization of active site residues, ns4a cofactor domain, and protease-cofactor interactions.the gene expression of bovine viral diarrhea virus (bvdv), a pestivirus, occurs via translation of a hypothetical polyprotein that is processed cotranslationally and posttranslationally by viral and cellular enzymes. a protease located in the n-terminal region of nonstructural (ns) protein ns3 catalyzes the cleavages, leading to the release of ns4a, ns4b, ns5a, and ns5b. our study provides experimental evidence that histidine at position 1658 and aspartic acid at position 1686 constitute togethe ...200010915606
[ocular manifestation in dengue fever].dengue-fever is a mosquito transmitted viral disease. it is endemic mainly in south-east asia and africa. the clinical manifestation is divided into different stages. ocular manifestations in travellers have been rarely reported.200010916388
[identification of the encephalitis equine virus, parana, brazil].in the period of 1996-1999 some virus associated with encephalitis have been reported in horses from different regions of paraná state, brazil. to identify the etiologic agent associated with this illness, mosquitoes and serum samples were collected in the endemic area.200010920444
[serological survey on arbovirus infection in residents of an ecological reserve].serological inquires conducted in the ribeira valley, s. paulo state, brazil, showed an intense circulation of pathogenic arboviruses in the region. the goal was to verify the prevalence of arboviral infections in people living at the local ecological, and its potential association with these population' individual and familiar characteristics.200010920445
the molecular epidemiology of kokobera virus.we describe herein the molecular epidemiology and phylogeny of kokobera (kok) virus, a flavivirus found in australia and papua new guinea. we sequenced a region encompassing the 200 nucleotides of the 3' terminus of the ns5 gene, and the first 300 nucleotides of the 3' untranslated region (utr). the study included 25 isolates of the virus, including an isolate from png, and several recent isolates from the south-west of western australia (wa), where the virus had not previously been detected. we ...200010930658
chimeric yellow fever/dengue virus as a candidate dengue vaccine: quantitation of the dengue virus-specific cd8 t-cell response.we have constructed a chimeric yellow fever/dengue (yf/den) virus, which expresses the premembrane (prm) and envelope (e) genes from den type 2 (den-2) virus in a yf virus (yfv-17d) genetic background. immunization of balb/c mice with this chimeric virus induced a cd8 t-cell response specific for the den-2 virus prm and e proteins. this response protected yf/den virus-immunized mice against lethal dengue encephalitis. control mice immunized with the parental yfv-17d were not protected against de ...200010933719
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