identification of a kunjin/west nile-like flavivirus in brains of patients with new york encephalitis.molecular analysis of brains from patients of the recent new york city encephalitis outbreak reveals the presence of a flavivirus not previously described in the americas.199910520637
electron microscopic diagnosis of human flavivirus encephalitis: use of confocal microscopy as an aid.the distinction between intracranial viral infections and inflammatory conditions requiring immunosuppression is important. although specific laboratory reagents are readily available for some viruses, diagnosis of arbovirus infection is more difficult. transmission electron microscopy (tem) theoretically allows identification of viral particles independent of reagent availability, but it has limited sensitivity. we report two cases of human flavivirus encephalitis diagnosed by tem. laser scanni ...199910524522
loss of dimerisation of the nonstructural protein ns1 of kunjin virus delays viral replication and reduces virulence in mice, but still allows secretion of ns1.the flavivirus nonstructural protein ns1 has been implicated in viral rna replication, although its precise role has not been identified. in its native state ns1 exists as a heat labile homodimer that is thought to be required for ns1 function and secretion. however, we have recently identified a cdna clone of kun virus (flsd) that replicates efficiently in cell culture but produces and secretes ns1 in monomeric form. sequence analysis of the ns1 gene in flsd revealed a single amino acid substit ...199910544130
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 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 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
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
studies on the serological cross-reaction between dengue and japanese encephalitis.antibody responses of sero-confirmed flavivirus-infected patients were investigated by hemagglutination-inhibition (hi) tests against acute phase sera (s1) and convalescent phase sera (s2) using je virus (jev) jagar# 01 strain antigen (j-ag) and dengue virus (dv) type 1 hawaiian strain antigen (d-ag). analysis of the test results showed that depending on the combinations of hi responses to both antigens, the sero-confirmed patients could be divided into five classes: primary je, secondary je, pr ...199710592825
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 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
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
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
mutational analysis of the gb virus b internal ribosome entry 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
rapid diagnosis of primary dengue fever by the immunochromatographic test and by electron microscopy--a case report.a 21-year-old woman presented with an acute febrile illness after a two-week holiday in jamaica. her symptoms started two days after return, with sudden onset of continuous high fever (> 39 degrees c), dizziness and nausea. three days later she developed a generalized macular rash, which led to the tentative diagnosis "acute dengue fever." laboratory confirmation was achieved by demonstrating anti-dengue igm and igg antibodies in paired sera; in addition, flavivirus particles were directly visua ...199910624599
ultrastructural aspects of the dengue virus (flavivirus) particle morphogenesis.the pathway of dengue virus infection in both mosquito and vero cells in culture has been described. however, a number of stages associated with dengue virus morphogenesis remain unclear. for this reason further study involving electron microscopic in situ hybridisation of viral rna and immunolocalisation of envelope proteins was carried out. the data obtained support the hypothesis that both viral rna and viral proteins assemble when anchored to the viral-induced smooth membrane structures whic ...199910626007
perspectives for the treatment of infections with flaviviridae.the family flaviviridae contains three genera: hepacivirus, flavivirus, and pestivirus. worldwide, more than 170 million people are chronically infected with hepatitis c virus and are at risk of developing cirrhosis and/or liver cancer. in addition, infections with arthropod-borne flaviviruses (such as dengue fever, japanese encephalitis, tick-borne encephalitis, st. louis encephalitis, murray valley encephalitis, west nile, and yellow fever viruses) are emerging throughout the world. the pestiv ...200010627492
malaria, arbovirus and hepatitis infections in macaca fascicularis from malaysia.naturally occurring malaria, arbovirus infection and hepatitis in monkeys can be a hazard for the investigator and might interfere with the outcome of experiments. 63 young adult macaca fascicularis from malaysia were screened for these infections. about 1 year after their arrival in france, parasitaemia due to plasmodium spp., was present in 6.4% of the animals and specific antibodies in 55.5%. 19 of 35 initially positive monkeys were tested again 2 years later. parasitaemia was found in 1 of 4 ...198410628790
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
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
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
gb virus c/hepatitis g virus infection in saudi arabian blood donors and patients with cryptogenic hepatitis.viral hepatitis is a common infection in the developing countries. aside from hepatitis a-e viruses, a novel hepatitis virus termed gbv-c, or hgv, was recently described. we have studied the prevalence of this virus among saudi arabian healthy blood donors (n = 200) and patients with cryptogenic (non-a-e) hepatitis (n=71). after serum extraction and rna reverse transcription, amplification was carried out by the polymerase chain reaction (pcr), using primers for the 5' noncoding region (ncr), ns ...200010664407
transient expression of cellular polypyrimidine-tract binding protein stimulates cap-independent translation directed by both picornaviral and flaviviral internal ribosome entry sites in vivo.the regulation of cap-independent translation directed by the internal ribosome entry sites (iress) present in some viral and cellular rnas is poorly understood. polypyrimidine-tract binding protein (ptb) binds specifically to several viral iress. ires-directed translation may be reduced in cell-free systems that are depleted of ptb and restored by reconstitution of lysates with recombinant ptb. however, there are no data concerning the effects of ptb on ires-directed translation in vivo. we tra ...200010669736
phylogeny of the genus flavivirus using complete coding sequences of arthropod-borne viruses and viruses with no known vector.attempts to define the evolutionary relationships and origins of viruses in the genus flavivirus are hampered by the lack of genetic information particularly amongst the non-vectored flaviviruses. using a novel protocol for sequence determination, the first complete coding sequence of st louis encephalitis virus and those of two representative non-vectored flaviviruses, rio bravo (isolated from bat) and apoi (isolated from rodent), are reported. the encoded polyproteins of rio bravo and apoi vir ...200010675416
japanese encephalitis dna vaccine candidates expressing premembrane and envelope genes induce virus-specific memory b cells and long-lasting antibodies in swine.swine are an important amplifier of japanese encephalitis (je) virus in the paradomestic environment. in this study, two je dna vaccine candidates were evaluated for immunogenicity in swine. both vaccine plasmids encode a cassette consisting of the signal of premembrane (prm), prm, and envelope (e) coding regions of je virus. one plasmid, designated pcjeme, is based on a commercial vector (pcdna3), whereas the other plasmid, designated pnjeme, is based on a vector (pngvl4a) designed to address s ...200010683326
a case of dengue from pune, india.dengue is an acute infectious disease, caused by a single stranded ribonucleic acid (rna) virus of the family of flaviviridae, genus flavivirus, transmitted by aedes mosquitos, the most important vectors being aedes aegypti and aedes albopictus. there are four serotypes, den-1, den-2, den-3, den-4 that are nearly human specific. the geographical distribution of dengue is pantropical, except for madagascar and some african regions. it is endemo-epidemic in tropical and subtropical countries inclu ...200010689245
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
gb virus c/hepatitis g virus infections in traumatologic outpatients, chronic non-a-e hepatitis and extrahepatic virus c/hepatitis g virus (gbv-c/hgv) is a recently discovered flavivirus of still unknown pathogenic relevance. we examined traumatologic outpatients to determine gbv-c/hgv viremia for further epidemiological studies, as blood donors hitherto used as controls represent healthy individuals without risk factors. anti-gbv-c/hgv antibodies were detectable in 13.2% (95% confidence interval [ci] 9.3-18.2) and gbv-c/hgv rna was detectable in 4.5% (95% ci 2.4-8.2) of the outpatients. in chronic non- ...200010697788
chimeric dengue type 2 (vaccine strain pdk-53)/dengue type 1 virus as a potential candidate dengue type 1 virus vaccine.we constructed chimeric dengue type 2/type 1 (den-2/den-1) viruses containing the nonstructural genes of den-2 16681 virus or its vaccine derivative, strain pdk-53, and the structural genes (encoding capsid protein, premembrane protein, and envelope glycoprotein) of den-1 16007 virus or its vaccine derivative, strain pdk-13. we previously reported that attenuation markers of den-2 pdk-53 virus were encoded by genetic loci located outside the structural gene region of the pdk-53 virus genome. chi ...200010708416
cis- and trans-acting elements in flavivirus rna replication.most of the seven flavivirus nonstructural proteins (ns1 to ns5) encoded in the distal two-thirds of the rna positive-sense genome are believed to be essential components of rna replication complexes. to explore the functional relationships of these components in rna replication, we used trans-complementation analysis of full-length infectious rnas of kunjin (kun) virus with a range of lethal in-frame deletions in the nonstructural coding region, using as helper a repbhk cell line stably produci ...200010708442
comparison of panbio dengue duo igm and igg capture elisa and venture technologies dengue igm and igg dot blot.a number of commercial elisa for dengue diagnosis have recently become available, though direct comparison between these assays have not been published.200010720818
the west nile virus outbreak of 1999 in new york: the flushing hospital experience.west nile virus (wnv) is a mosquito-borne flavivirus, which has been known to cause human infection in africa, the middle east, and southwestern asia. it has also been isolated in australia and sporadically in europe but never in the americas. clinical features include acute fever, severe myalgias, headache, conjunctivitis, lymphadenopathy, and a roseolar rash. rarely is encephalitis or meningitis seen. during the month of august 1999, a cluster of 5 patients with fever, confusion, and weakness ...200010722421
gb virus c/hepatitis g virus infection is frequent in american children and young adults.the novel flavivirus gb virus c/hepatitis g virus (gbv-c/hgv) has been detected in approximately 2% of blood donors in the united states, and neutralizing antibody to the envelope protein (e2), a marker of previous infection with gbv-c/hgv, is present in approximately 9% of donors. the rate of gbv-c/hgv infection among american children is unknown. to determine whether viral infection might occur during childhood, 160 serum specimens (obtained from blood bank samples) from children and young adu ...200010722444
infectious cdna clones of langat tick-borne flavivirus that differ from their parent in peripheral neurovirulence.tick-borne flavivirus strain langat tp21 (lgt tp21) recovered from ticks, is naturally attenuated for humans but retains demonstrable neurovirulence and peripheral virulence ("neuroinvasiveness") for mice. previously a mutant, strain e5, less virulent for mice was derived from lgt tp21. multiple attempts to prepare a full-length infectious tp21 cdna from cdna fragments cloned in e. coli were uniformly unsuccessful. a more informative sequence than that obtained from these cloned cdna fragments a ...200010725214
bovine viral diarrhoea virus and bovine herpesvirus-1 prime uninfected macrophages for lipopolysaccharide-triggered apoptosis by interferon-dependent and -independent pathways.the flavivirus bovine viral diarrhoea (bvd) virus exists in two biotypes, cytopathic (cp) and non-cytopathic (ncp), defined by their effect on cultured cells. cp bvd virus-infected cells undergo apoptosis and may promote apoptosis in uninfected cells by an indirect mechanism. macrophages (mφ) infected with cp, but not ncp, bvd virus release a factor(s) in the supernatant capable of priming uninfected mφ for activation-induced apoptosis in response to lipopolysaccharide. a possible role o ...200010725412
targets for inhibition of hepatitis c virus replication.considerable progress has been made in characterizing the proteins involved in hepatitis c virus (hcv) replication, despite the lack of a cell culture system. a number of systems have been developed to examine the processes involved in viral replication, including the initiation and processing of the viral proteins required for rna replication, the unwinding activities of the rna helicase and the synthesis of rna by the viral polymerase. these processes have been examined using individually clon ...199810726058
the hepatitis c virus ns3 proteinase: structure and function of a zinc-containing serine proteinase.the hepatitis c virus (hcv) ns3 protein contains a serine proteinase domain implicated in the maturation of the viral polyprotein. ns3 forms a stable heterodimer with ns4a, a viral membrane protein that acts as an activator of the ns3 proteinase. the three-dimensional structure of the ns3 proteinase complexed with an ns4a-derived peptide has been determined. the ns3 proteinase adopts a chymotrypsin-like fold. a beta-strand contributed by ns4a is clamped between two beta-strands within the n term ...199810726060
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-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 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 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
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
human recombinant laminin-binding protein: isolation, purification, and crystallization.the mrna of the precursor of laminin-binding protein (lbp) was isolated from a human embryo kidney cell line and cloned. the determined sequence of the lbp gene showed complete identity with the lbp genes isolated from human lung and large intestine cells. the human lbp was expressed by e. coli cells, and it was purified using ni-nta-sepharose chromatography. the mobility of the homogeneous recombinant human laminin-binding protein on sds-page was 43 kd. a mixture of eight murine monoclonal anti ...200010851030
a model for the hepatitis c virus envelope glycoprotein e2.several experimental studies on hepatitis c virus (hcv) have suggested the envelope glycoprotein e2 as a key antigen for an effective vaccine against the virus. knowledge of its structure, therefore, would present a significant step forward in the fight against this disease. this paper reports the application of fold recognition methods in order to produce a model of the hcv e2 protein. such investigation highlighted the envelope protein e of tick borne encephalitis virus as a possible template ...200010861927
mother-to-infant transmission of gb virus type c/hgv.the potentially hepatotropic flavivirus-like virus, gb virus type c (gbv-c)/hgv, has been detected in a few patients with acute and chronic hepatitis and in a certain proportion of blood donors and recipients of blood or blood components.200010864996
report on ticks collected in the southeast and mid-west regions of brazil: analyzing the potential transmission of tick-borne pathogens to man.specimens of ticks were collected in 1993, 1996, 1997, and 1998, mostly from wild and domestic animals in the southeast and mid-west regions of brazil. nine species of amblyommidae were identified: anocentor nitens, amblyomma cajennense, amblyomma ovale, amblyomma fulvum, amblyomma striatum, amblyomma rotundatum, boophilus microplus, boophilus annulatus, and rhipicephalus sanguineus. the potential of these tick species as transmitters of pathogens to man was analyzed. a flaviviridade flavivirus ...199910881097
[the immune state against yellow fever vaccinal virus (17d) in 2 populations of bahia state, brazil].the occurrence of cases of yellow fever (yf) and also the extensive distribution of a. aegypti in brazil, inspired a study about the estimate of immunity against vaccinal virus (17d) among the residents at two cities of the bahia state, ipupiara (n = 461) and prado (n = 228). at this non-endemic area of yf, the search for serology antibody against 17d (ab17d) and 18 another arbovirus was made thereby hemagglutination inhibition (hi). only 1.2% (8/689) showed ab17d, six of those with monotypic so ...200010881117
human skin langerhans cells are targets of dengue virus infection.dengue virus (dv), an arthropod-borne flavivirus, causes a febrile illness for which there is no antiviral treatment and no vaccine. macrophages are important in dengue pathogenesis; however, the initial target cell for dv infection remains unknown. as dv is introduced into human skin by mosquitoes of the genus aedes, we undertook experiments to determine whether human dendritic cells (dcs) were permissive for the growth of dv. initial experiments demonstrated that blood-derived dcs were 10-fold ...200010888933
[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
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 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
gbv-c/hgv genotypes: proposed nomenclature for genotypes 1-5.the gb virus-c and hepatitis g virus (gbv-c/hgv) are variants of the same flavivirus. this proposal attempts to clarify the conflicting nomenclature for gbv-c/hgv genotypes. the first three genotypes described were genotype 1 (west africa); genotype 2 (us/europe) and genotype 3 (asia). subsequently, two groups published data from south africa and southeast asia both stating the presence of a novel "4th genotype." these isolates are distinct phylogenetically. it is proposed that the nomenclature ...200010935992
chimeric langat/dengue viruses protect mice from heterologous challenge with the highly virulent strains of tick-borne encephalitis virus.langat virus (lgt), a tick-borne flavivirus, is naturally attenuated for humans but it is very virulent in scid mice. in contrast, viable recombinant chimeras of lgt (prem and e genes) and dengue type 4 virus (all other sequences) recovered in mosquito cell culture were completely attenuated in scid mice but still capable of providing protection against lgt. to develop the chimeras into vaccine candidates, we adapted them to replicate efficiently in simian vero cells, a satisfactory substrate fo ...200010936085
characterization of monoclonal antibodies against hokkaido strain tick-borne encephalitis virus.a tick-borne encephalitis (tbe) patient was found in hokkaido in 1993, and tbe viruses were isolated from animals and ticks in our previous studies. to develop a diagnostic reagent to identify tbe viruses, monoclonal antibodies (mabs) were produced against the tbe virus strain hokkaido (oshima 5-10). seven mabs were obtained which reacted with the envelope protein of the oshima 5-10 strain. these mabs were flavivirus genus-specific, tbe virus complex-specific or tbe virus type-specific. the mabs ...200010941938
processing of gb virus b non-structural proteins in cultured cells requires both ns3 protease and ns4a cofactor.the identification of antivirals and vaccines against hepatitis c virus (hcv) infection is hampered by the lack of convenient animal models. the need to develop surrogate models has recently drawn attention to gb virus b (gbv-b), which produces hepatitis in small primates. in a previous study in vitro, it was shown that gbv-b ns3 protease shares substrate specificity with the hcv enzyme, known to be crucial for virus replication. in this report, gbv-b ns3 activity on gbv-b precursor proteins has ...200010950975
phylogeny of the genus flavivirus using complete coding sequences of arthropod-borne viruses and viruses with no known vector 200010950993
dengue infection presenting with central nervous system manifestation.the objective of this study was to investigate the possibility of dengue virus infection causing an abnormal neurologic presentation. between 1996 and 1998, all pediatric patients with clinical manifestations of encephalitis-like illness who were admitted to the department of pediatrics, siriraj hospital were prospectively studied for any evidence of dengue virus infection. the diagnosis of dengue virus infection was based on mosquito viral isolation and serologic and polymerase chain reaction ( ...200010961794
crystal structure of dengue virus ns3 protease in complex with a bowman-birk inhibitor: implications for flaviviral polyprotein processing and drug design.dengue viruses are members of the flaviviridae and cause dengue fever and the more severe dengue hemorrhagic fever. although nearly 40 % of the world's population is at risk of dengue infection, there is currently no effective vaccine or chemotherapy for the disease. processing of the dengue polyprotein into structural and non-structural proteins in a host, which is essential for assembly of infective virions, is carried out by the combined action of host proteases and the trypsin-like, two-comp ...200010966782
modulatory effects of the human heat shock protein 70 on dna vaccination.dna vaccination with the plasmid expressing japanese encephalitis virus (jev) nonstructural protein 1 (pjns1) has been shown to induce effective immunity against jev infection. to further increase the efficacy of pjns1 dna vaccination, we coinjected pjns1 with a plasmid that expresses heat shock protein 70.1 (phsp70.1) into mice. we found that coinjection of phsp70.1 enhanced both t cell proliferation and cytotoxic effects, but not the antibody response to jev. moreover, mice immunized with both ...200010971139
substitutions at the putative receptor-binding site of an encephalitic flavivirus alter virulence and host cell tropism and reveal a role for glycosaminoglycans in entry.the flavivirus receptor-binding domain has been putatively assigned to a hydrophilic region (fg loop) in the envelope (e) protein. in some flaviviruses this domain harbors the integrin-binding motif arg-gly-asp (rgd). one of us has shown earlier that host cell adaptation of murray valley encephalitis virus (mve) can result in the selection of attenuated variants altered at e protein residue asp(390), which is part of an rgd motif. here, a full-length, infectious cdna clone of mve was constructed ...200010982329
full-length gb virus c (hepatitis g virus) rna transcripts are infectious in primary cd4-positive t virus c (gbv-c or hepatitis g virus) is a recently described flavivirus which frequently leads to chronic viremia in humans. although gbv-c is associated with acute posttransfusion hepatitis, it is not clear if the virus is pathogenic for humans. we constructed a full-length cdna from the plasma of a person with chronic gbv-c viremia. peripheral blood mononuclear cells (pbmcs) transfected with full-length rna transcripts from this gbv-c clone resulted in viral replication. this was demonstrat ...200010982359
gb virus c/hepatitis g virus replicates in human haematopoietic cells and vascular endothelial cells.a novel flavivirus, gb virus c (gbv-c)/hepatitis g virus (hgv), has been detected in chronic liver disease patients. it is known that the viral rna can be detected in approximately 5% of american blood donors. however, the implications for liver disease and the sites of virus replication remain unknown. possible sites of virus replication were studied by using cell lines and/or primary cells derived from human lymphoid cells, myeloid cells, hepatocytes and endothelial cells. rna was detected by ...200010993934
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