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insect-transmitted vertebrate viruses: flaviviridae.the flaviviridae include almost 70 viruses, nearly half of which have been associated with human disease. these viruses are among the most important arthropod-borne viruses worldwide and include dengue, yellow fever, and japanese encephalitis viruses. morbidity and mortality caused by these viruses vary, but collectively they account for millions of encephalitis, hemorrhagic fever, arthralgia, rash, and fever cases per year. most of the members of this family are transmitted between vertebrate h ...19938100566
immunofluorescence studies on the replication of some arboviruses in nucleated and enucleated cells.porcine stable kidney (ps) or vero cells infected with either flavi-(japanese encephalitis--je, west nile--wn, and dengue--den-2) or alphaviruses (chikungunya--chik and sindbis--sin) were stained in indirect fluorescent antibody (fa) assay with anti-je virus monoclonal (moab) hx-3 (flavivirus cross-reactive) and polyclonal (immune pf) antibodies. by 48 hr post infection (p.i.), 15 to 20% of the three flaviviruses and chik virus infected cells, which revealed positive cytoplasmic immunofluorescen ...19938105654
analysis of the structural protein gene sequence shows kyasanur forest disease virus as a distinct member in the tick-borne encephalitis virus serocomplex.kyasanur forest disease (kfd) virus is a highly pathogenic member of the family flaviviridae producing a haemorrhagic disease in infected human beings. despite this high pathogenicity and potential epidemiological importance, there have been relatively few detailed antigenic or molecular studies on kfd virus. the nucleotide sequences of the genes encoding the structural proteins of the virus have now been determined. from these data we conclude that kfd virus is a distinct member in the tick-bor ...19948113732
geographic distribution and evolution of yellow fever viruses based on direct sequencing of genomic cdna fragments.we have compared the nucleotide sequence of an envelope protein gene fragment encoding amino acids 291 to 406 of 22 yellow fever (yf) virus strains of diverse geographic and host origins isolated over a 63 year time span. the nucleotide fragment of viral rna was examined by direct sequencing of a pcr product derived from complementary dna. alignment with the prototype asibi strain sequence showed divergence of 0 to 21.5% corresponding to a maximum of 5.2% divergence in the amino acid sequence. t ...19948113765
[flavivirus meningitis after tick bite: a new case in an urban area]. 19938115337
medically important arboviruses of the united states and canada.of more than 500 arboviruses recognized worldwide, 5 were first isolated in canada and 58 were first isolated in the united states. six of these viruses are human pathogens: western equine encephalitis (wee) and eastern equine encephalitis (eee) viruses (family togaviridae, genus alphavirus), st. louis encephalitis (sle) and powassan (pow) viruses (flaviviridae, flavivirus), lacrosse (lac) virus (bunyaviridae, bunyavirus), and colorado tick fever (ctf) virus (reoviridae, coltivirus). their scien ...19948118792
[tick-borne encephalitis in central europe: a rare cause of autochthonous meningo-encephalo-myelitis]. 19948140082
dengue: the risk to developed and developing countries.dengue viruses are members of the flaviviridae, transmitted principally in a cycle involving humans and mosquito vectors. in the last 20 years the incidence of dengue fever epidemics has increased and hyperendemic transmission has been established over a geographically expanding area. a severe form, dengue hemorrhagic fever (dhf), is an immunopathologic disease occurring in persons who experience sequential dengue infections. the risk of sequential infections, and consequently the incidence of d ...19948146129
[health economics of early summer meningoencephalitis in austria. effects of a vaccination campaign 1981 to 1990].tick-borne encephalitis (tbe) was until the early 1980s among the most frequent causes of viral induced central-nervous infectious diseases in austria. since 1981 the vaccination was forced by intensive media campaigns. aim of this study was to investigate the effects of the media campaigns and to evaluate them under health economic criteria. the number of hospitalized tbe-cases declines from 1981 to 1990, the linear trend shows a reduction from 427 to 109. if the linear trend from 1971 to 1980 ...19938147001
[what is the status of immune prevention of "tick bite diseases"?]. 19948147025
iguape: a newly recognized flavivirus from são paulo state, brazil.a new virus, sp an 71686, was isolated from sentinel mice exposed in a forest area in iguape county, são paulo state, brazil, in 1979. the results suggest [hemagglutination inhibition (hi), complement fixation, neutralization, and elisa] that sp an 71686 virus is a new arbovirus and that it demonstrates some cross-reactivity with other members of the family flaviviridae, but can be differentiated from them. although there is an intensive circulation of several arboviruses in the area, the only d ...19938150595
[presence of antibodies against venezuelan equine encephalitis virus subtype vi in patients with acute febrile illness].in argentina, there is no record of human cases produced by dengue virus (flavivirus), but paraguay and brasil (neighbouring countries) have notified human outbreaks of dengue haemorrhagic fever. in this report, we inform the serological results of a limited human outbreak of a dengue-like acute illness that occurred in general belgrano island, formosa, argentina in april 1989. this island is 35 km far from clorinda city of paraguay river, with a human population of 150 inhabitants. the weather ...19938153352
recombinant vaccinia viruses co-expressing dengue-1 glycoproteins prm and e induce neutralizing antibodies in mice.four recombinant vaccinia viruses expressing different portions of the dengue type 1 virus (den-1) genome (c-prm-e-ns1-ns2a-ns2b; prm-e; prm-e-ns1-ns2a-ns2b; or ns1-ns2a) were constructed in order to establish the most immunogenic configuration of den-1 proteins. both recombinants producing prm and e in the absence of c induced the synthesis of extracellular forms of e in vitro. mice inoculated with these two recombinants produced den-1 neutralizing (neut) and haemagglutination inhibiting (hai) ...19948165861
both ns3 and ns4a are required for proteolytic processing of hepatitis c virus nonstructural proteins.the proteolytic cleavages at the ns3-ns4a, ns4a-ns4b, ns4b-ns5a, and ns5a-ns5b junctions of hepatitis c virus (hcv) polyprotein are effected by the virus-encoded serine protease contained within ns3. using transient expression in hela cells of cdna fragments that code for regions of the hcv polyprotein, we studied whether viral functions other than ns3 are required for proteolytic processing at these sites. we found that, in addition to ns3, a c-terminal 33-amino-acid sequence of the ns4a protei ...19948189513
ns2b-3 proteinase-mediated processing in the yellow fever virus structural region: in vitro and in vivo studies.several of the cleavages required to generate the mature nonstructural proteins from the flaviviral polyprotein are known to be mediated by a complex consisting of ns2b and a serine proteinase domain located in the n-terminal one-third of ns3. these cleavages typically occur after two basic residues followed by a short side chain residue. cleavage at a similar dibasic site in the structural region is believed to produce the c terminus of the virion capsid protein. to study this cleavage, we deve ...19948189517
first isolations of arboviruses from phlebotomine sand flies in west africa.for the first time in west africa, arboviruses were isolated from phlebotomine sand fly pools. one strain of chandipura virus (a vesiculovirus), four strains of saboya virus (a flavivirus), and one strain of a not yet identified virus were isolated. three hundred twenty-two pools were established from a population of 33,917 sand flies caught in co2 light traps in the ferlo sahelian region of senegal from november 1991 to december 1992. this is the first isolation of chandipura virus from any art ...19948203705
completion of kunjin virus rna sequence and recovery of an infectious rna transcribed from stably cloned full-length cdna.completion of the kunjin virus (kun) rna sequence showed that it is the longest flavivirus sequence reported (11,022 bases), commencing with a 5' noncoding region of 96 bases. the 3' noncoding sequence of 624 nucleotides included a unique insertion sequence of 46 bases adjacent to the stop codon, but otherwise it had properties similar to those of rnas of closely related flaviviruses. a full-length kun cdna clone which could be stably propagated in escherichia coli dh5 alpha was constructed; sp6 ...19948207832
phylogenetic relationships of dengue-2 viruses.rna oligonucleotide fingerprinting studies on a large number of virus isolates previously demonstrated considerable genetic variation in isolates of dengue (den)-2 serotype. we report the entire envelope (e) glycoprotein gene and deduced amino acid sequences of 16 den-2 viruses and the phylogenetic relationships of these, plus 17 additional published den e gene sequences. comparison of den-2 e glycoprotein gene sequences revealed base substitutions scattered throughout the entire gene with as mu ...19938212556
the ns 3 nonstructural protein of flaviviruses contains an rna triphosphatase activity.the genome of flaviviruses consists of an infectious single-stranded rna molecule which contains a type 1 cap structure at the 5'-terminus. the cap is synthesized by rna triphosphatase, guanylyltransferase and methyltransferase. since flaviviruses replicate in the cytoplasm, it can be assumed that these functions are performed by virus-coded proteins. we previously showed that subtilisin treatment of membranes isolated from cells infected with the west nile flavivirus results in release of a 50 ...19938212562
ir1 genes, peripheral cross-tolerance and immunodominance in mhc class i-restricted t-cell responses: an old quagmire revisited.previous studies have shown that peripheral tolerance of one mhc molecule may influence the ability of an animal to respond to a particular antigenic determinant in the context of another mhc molecule (cross-tolerance). we describe here an investigation of the extent to which the presence of mhc molecules other than the one involved in tc cell recognition affected whether or not a particular "antigen" (mhc/peptide) was recognized during the response of mice to infection with the flavivirus, west ...19938225372
seroepidemiology of dengue and other arboviruses in a natural population of toque macaques (macaca sinica) at polonnaruwa, sri lanka.a seroepidemiological study of arboviruses infecting 115 wild toque macaques (macaca sinica) at polonnaruwa, sri lanka showed a high prevalence of antibodies to dengue and lumbo viruses. there was low seroprevalence of chandipura (2/115) and batai (1/115) virus antibodies, but no seropositivity to chikungunya or sindbis. there was no serological evidence of infection by japanese encephalitis (je) virus in spite of large human epidemics in the study area, indicating that toque macaques are unlike ...19938230174
[flavivirus infections in tropical areas]. 19938236844
use of ns3 consensus primers for the polymerase chain reaction amplification and sequencing of dengue viruses and other flaviviruses.consensus primers for the polymerase chain reaction were designed based on conserved motifs within the serine protease and rna helicase domains encoded by the ns 3 genes of dengue and other flaviviruses. target fragments of 470 bp were amplified on cdna templates synthesized from rnas of dengue types 1, 2, 3, and 4, japanese encephalitis, kunjin, and yellow fever viruses using random or specific downstream primers. pcr of oligo(dt)-primed cdnas from japanese encephalitis and kunjin viral rnas di ...19938240006
possible clinical infection with edge hill virus. 19938249078
classification of a new member of the tbe flavivirus subgroup by its immunological, pathogenetic and molecular characteristics: identification of subgroup-specific pentapeptides.the antigenic, pathogenic and molecular characteristics of turkish sheep encephalitis (tse) virus, strain tte80, were compared with other members of the tick-borne encephalitis (tbe) virus complex. monoclonal antibodies with defined specificity for the flavivirus envelope glycoprotein distinguished tse virus from louping ill (li), western or far eastern tbe, langat and powassan virus in indirect immunofluorescence, haemagglutination-inhibition and neutralization tests. on the other hand, tse vir ...19938249442
molecular approaches for the treatment of hemorrhagic fever virus infections.viruses causing hemorrhagic fevers in man belong to the following virus groups: togavirus (chikungunya), flavivirus (dengue, yellow fever, kyasanur forest disease, omsk hemorrhagic fever), arenavirus (argentinian hemorrhagic fever, bolivian hemorrhagic fever, lassa fever), filovirus (ebola, marburg), phlebovirus (rift valley fever), nairovirus (crimian-congo hemorrhagic fever) and hantavirus (hemorrhagic fever with renal syndrome, nephropathic epidemia). hemorrhagic fever virus infections can be ...19938250543
mapping the flv locus controlling resistance to flaviviruses on mouse chromosome 5.genetically determined resistance to flaviviruses in mice is a dominant trait conferred by alleles at a single autosomal locus designated flv, but no gene products have been associated with this locus and the mechanism of resistance is not well understood. to further characterize this model of genetic resistance, we conducted mapping studies to determine the chromosomal location of flv. because of evidence suggesting that the flv locus is on chromosome 5, three-point backcross linkage analyses w ...19948254755
structural changes and functional control of the tick-borne encephalitis virus glycoprotein e by the heterodimeric association with protein prm.we have used tick-borne encephalitis virus to study the involvement of acidic compartments during the entry and release phases of flavivirus infection and to elucidate the role of protein prm in immature virions. elevation of the ph in acidic intracellular compartments by either bafilyomycin a1, a specific inhibitor of the vacuolar type h(+)-atpase or by nh4cl had a strong inhibitory effect during virus penetration and also prevented the cleavage of prm when added in the late phase of the viral ...19948259646
rapid identification of flaviviruses based on conserved ns5 gene sequences.two conserved regions in the sequence of the ns5 gene of flaviviruses were identified. primers were designed from the consensus sequence of these regions and were used in a reverse transcription/polymerase chain reaction (rt/pcr) to amplify a region of the central european tick-borne encephalitis virus kumlinge ns5 gene. the authenticity of the amplified fragment was confirmed by nucleotide sequencing. a band of the expected size was also obtained when this rt/pcr was applied to 13 other flavivi ...19938263114
the molecular biology of tick-borne encephalitis virus. review article.tick-borne encephalitis (tbe) virus is a member of the flavivirus genus and the family flaviviridae. like other flaviviruses such as yellow fever, japanese encephalitis or the dengue viruses, it is an important human pathogen, endemic in many european countries, russia and china. the disease can be effectively prevented by vaccination with a formalin-inactivated whole virus vaccine. in recent years major advances have been made in the understanding of the molecular biology of tbe virus, includin ...19938267950
rapid detection of viruses of the tick-borne encephalitis virus complex by rt-pcr of viral rna.studies were performed to identify a pair of primers, specific for the tick-borne encephalitis (tbe) virus complex of the flaviviridae, with which to develop a rapid and specific identification system based on reverse transcription and the polymerase chain reaction (rt-pcr). the specificity of a putative primer pair was examined by rt-pcr of representative viruses from other antigenic complexes of the flaviviridae and by computer sequence homology checks. all viruses of the tbe complex tested, w ...19938270650
rapid dengue diagnosis and interpretation. 19938277797
localization and functions of japanese encephalitis virus nonstructural proteins ns3 and ns5 for viral rna synthesis in the infected cells.recently it has been reported that japanese encephalitis virus (jev)-specific rnas can be synthesized in vitro in the subcellular fraction including outer-nuclear membrane (takegami and hotta, 1989). the results of western blot analysis and indirect immunofluorescence test using two kinds of monospecific antisera against jev nonstructural proteins ns3 and ns5 showed that ns3 and ns5 were membrane-associated proteins and formed the complex at the perinuclear site in the infected cells. both antis ...19938321152
site-directed mutagenesis of the tick-borne encephalitis virus ns3 gene reveals the putative serine protease domain of the ns3 protein.several mutations were introduced into the putative serine protease domain of the tick-borne encephalitis virus ns3 protein and into a possible internal cleavage site within the protein. the influence of these mutations on proteolytic activity of ns3 protein and ns3' protein formation was tested in vitro. it was found that ns3' formation was not dependent on the activity of the ns3 n-terminal serine protease. mutations affecting the ser-138 residue of the ns3 protein prohibited cleavage between ...19938344415
st louis encephalitis virus establishes a productive, cytopathic and persistent infection of sf9 cells.the sf9 cell line, commonly used for gene expression by recombinant baculovirus, has been productively infected by st louis encephalitis (sle) virus, a flavivirus. sle viral infection produced a c.p.e. in the sf9 cells characterized by giant cells and the presence of 10-fold fewer cells in the infected cultures after the first week of infection compared with uninoculated control cultures. infected sf9 cells expressed sle viral antigens, and intracellular virus particles were observed by electron ...19938345362
[virologic detection of arboviruses in greater cormorants].cormorants (phalacrocorax carbo, pelecaniformes) caught in southern moravia (czech republic) in 1989-1990 were examined for arbovirus infections. isolation experiments were carried out using blood samples of 56 birds. the results were negative. serological examinations of 31 birds were performed by haemagglutination-inhibition test (hit) using 5 arboviral antigens of the genera alphavirus (sindbis--sin) and flavivirus (tick-borne encephalitis--tbe, west nile--wn) and of the family bunyaviridae ( ...19938346623
nucleotide sequence of the envelope protein gene of the tick-borne flavivirus, kumlinge a52.the envelope protein gene of the tick-borne flavivirus, kumlinge a52, the proto-type finnish strain, has been amplified and sequenced.* the nucleotide and deduced amino acid sequence has been analyzed and compared with the closely related tick-borne encephalitis (tbe) virus, western subtype, strain neudoerfl, isolated in austria. although these two virus strains were isolated 12 years apart from different hosts and in different countries, the envelope proteins only differed by a single amino aci ...19938367941
assessment of the antigenic structure of tick-borne encephalitis virus by the use of synthetic peptides.the feasibility of using synthetic peptides for the identification of individual monoclonal antibody (mab)-defined epitopes was assessed on the basis of a structural model of the tick-borne encephalitis (tbe) virus envelope glycoprotein e. for this purpose a series of 19 synthetic peptides was prepared, covering most of the e protein sequence. each of the peptides was tested by elisa for reactivity with 19 protein e-specific mabs raised against tbe virus strain neudoerfl. specific reactivity was ...19938376978
genetic studies of flavivirus resistance in inbred strains derived from wild mice: evidence for a new resistance allele at the flavivirus resistance locus (flv).studies of genetic resistance to flavivirus infection in laboratory mice have led to the development of a single model in which resistance is conferred by an autosomal dominant gene designated flvr. because of evidence suggesting that wild mice carry virus resistance genes which are not present in laboratory mice, we compared flavivirus resistance in the inbred strains casa/rk, cast/ei, and mold/rk, which are derived directly from wild mice, and the congenic strains c3h/rv (flvr/flvr) and c3h/he ...19938380081
wesselsbron virus haemagglutination: studies with erythrocytes of various animal species at different ph and temperatures.the haemagglutinating (ha) properties of the nigerian strain of wesselsbron virus have been investigated using erythrocytes from a wide range of animals. the results showed that wesselsbron virus possesses ha activity when extracted using the sucrose and acetone method. the erythrocytes of goose, horse, donkey, pig, cattle, sheep, goat, monkey, man, rabbit, rat, guinea pig and chicken were agglutinated by wesselsbron virus at different ph values (5.75-7.0) and temperatures of 4 degrees c, room ( ...19938380321
rna-stimulated ntpase activity associated with yellow fever virus ns3 protein expressed in bacteria.the nonstructural protein ns3 of the prototypic flavivirus, yellow fever virus, was investigated for possession of an ntpase activity. the entire ns3 protein coding sequence and an amino-terminal truncated version thereof were engineered into escherichia coli expression plasmids. bacteria harboring these plasmids produced the expected polypeptides, which upon cell disruption were found in an insoluble aggregated material considerably enriched for the ns3-related polypeptides. solubilization and ...19938380474
nucleotide and deduced amino acid sequence of the envelope glycoprotein of omsk haemorrhagic fever virus; comparison with other flaviviruses.the gene encoding the envelope glycoprotein of omsk haemorrhagic fever (ohf) virus was cloned and sequenced. a freeze-dried preparation of infected suckling mouse brain suspension was used as the source material for viral rna. the derived cdna was amplified using the polymerase chain reaction and the cloned dna sequenced by dideoxynucleotide sequencing. alignment of the ohf virus sequence with those of other known tick-borne flaviviruses showed that they shared n-glycosylation sites, cysteine re ...19938381470
deletion analysis of dengue virus type 4 nonstructural protein ns2b: identification of a domain required for ns2b-ns3 protease activity.most proteolytic cleavages in the nonstructural protein (ns) region of the flavivirus polyprotein are effected by a virus-encoded protease composed of two viral proteins, ns2b and ns3. the n-terminal 180-amino-acid-region of ns3 includes sequences with homology to the active sites of serine proteases, and there is evidence that this portion of ns3 can mediate proteolytic cleavages. in contrast, nothing is known about required sequences in ns2b. we constructed a series of deletion mutations in th ...19938383225
viruses as teratogens.the ability of certain viruses to affect prenatal development in domestic animals is well documented. however, differentiating a viral-induced malformation from those caused by genetic or other environmental causes is a diagnostic dilemma. understanding how viruses interact with their embryo-fetal hosts and the potential consequences on prenatal development requires refining and dispelling some old concepts and injecting new insights into this diagnostic challenge. this article discusses several ...19938384522
nucleotide and deduced amino acid sequence of the envelope gene of the vasilchenko strain of tbe virus; comparison with other flaviviruses.a strain of tick-borne encephalitis virus known as vasilchenko (vs) exhibits relatively low virulence characteristics in monkeys, syrian hamsters and humans. the gene encoding the envelope glycoprotein of this virus was cloned and sequenced. alignment of the sequence with those of other known tick-borne flaviviruses and identification of the recognised amino acid genetic marker ehlpta confirmed its identity as a member of the tbe complex. however, vs virus was distinguishable from eastern and we ...19938384766
computer-assisted identification of a putative methyltransferase domain in ns5 protein of flaviviruses and lambda 2 protein of reovirus.a sequence motif that is conserved in a number of s-adenosylmethionine (sam)-utilizing methyltransferases and is implicated in sam binding was identified in the n-terminal portion of ns5 proteins of flaviviruses and in lambda 2 protein of reovirus. an additional conserved motif was shared by these viral proteins and two distinct groups of methyltransferases including as the prototypes rhodobacter capsulatus hydroxyneurosporene methylase (crtf gene product) and yeast 3,4-dihydroxy-5-hexaprenylben ...19938385698
characterization of the hepatitis c virus-encoded serine proteinase: determination of proteinase-dependent polyprotein cleavage sites.processing of the hepatitis c virus (hcv) h strain polyprotein yields at least nine distinct cleavage products: nh2-c-e1-e2-ns2-ns3-ns4a-ns4b-ns5a-ns5b-co oh. as described in this report, site-directed mutagenesis and transient expression analyses were used to study the role of a putative serine proteinase domain, located in the n-terminal one-third of the ns3 protein, in proteolytic processing of hcv polyproteins. all four cleavages which occur c terminal to the proteinase domain (3/4a, 4a/4b, ...19938386278
australian encephalitis in western australia, 1978-1991.to review the various clinical manifestations of murray valley encephalitis (mve) or kunjin virus encephalitis in patients in western australia.19938386796
presence of viral replicative intermediates in the liver and serum of patients infected with hepatitis c virus.hepatitis c virus (hcv) is a positive-polarity, single-stranded rna virus, distantly related to the pestivirus and flavivirus genera. these viruses replicate through the formation of a minus-strand rna intermediate, which encodes the positive-strand genome, which is subsequently encapsidated, enveloped, and released from infected cells. minus-strand rna is not found in the mature, circulating virions of flaviviruses. in an attempt to study the relative amounts of viral plus and minus strand in t ...19938387574
virological and immunological studies of wesselsbron virus in experimentally infected red sokoto (maradi) goats.red sokoto goats aged four to five months were experimentally infected with the nigerian strain of wesselsbron virus. viraemia commenced 24-72 hours after infection and lasted for 3-4 days. a febrile reaction which was mostly biphasic coincided with viraemia. a 50% mortality rate was observed among infected animals. the virus was re-isolated in mice from almost every tissue (liver, spleen, lungs, brain, kidney, adrenal, lymph node and heart) obtained from dead goats. complement fixing antigens w ...19938389498
invertebrate tissue culture as a tool to study insect-transmitted viruses: a brief introduction. 19938391527
flavivirus premembrane protein cleavage and spike heterodimer secretion require the function of the viral proteinase ns3.flavivirus protein biosynthesis involves the proteolytic processing of a single polyprotein precursor by host- and virus-encoded proteinases. in this study, the requirement for the proteolytic function of the viral proteinase ns3 for correct processing of a polyprotein segment encompassing the murray valley encephalitis virus structural proteins is shown. the ns3-mediated cleavage in the structural polyprotein region presumably releases the capsid protein from its membrane anchor and triggers th ...19938392191
arbovirus infections of humans in high-risk areas of south-eastern australia: a continuing study.to determine the current immune status of high-risk populations of new south wales and victoria to the arboviral pathogens, murray valley encephalitis (mve) and kunjin (kun) viruses, which are associated with australian encephalitis (ae), and ross river (rr) and kokobera (kok) viruses which are associated with polyarthritis. further, to estimate seroconversion rates to these viruses in high-risk populations over the 10-year period 1981-1991.19938393128
evaluation of vero cell lysate antigen for the elisa of flaviviruses.the vero cell lysate antigen for the enzyme-linked immunosorbent assay (elisa) of flaviviruses was evaluated for sensitivity, specificity including cross-reactions, and background by comparing with the standard elisa. human sera, in serial dilutions, were taken from subjects 14, 35, and 210 days postvaccination with 17d antigen. early after injection, high sensitivity (82.9%) was shown by the cell lysate antigen method. late after infection, high sensitivity was achieved by the standard method ( ...19938395596
hepatitis c virus ns3 protein polynucleotide-stimulated nucleoside triphosphatase and comparison with the related pestivirus and flavivirus enzymes.sequence motifs within the nonstructural protein ns3 of members of the flaviviridae family suggest that this protein possesses nucleoside triphosphatase (ntpase) and rna helicase activity. the rna-stimulated ntpase activity of this protein from prototypic members of the pestivirus and flavivirus genera has recently been established and enzymologically characterized. here, we experimentally demonstrate that the ns3 protein from a member of the third genus of flaviviridae, human hepatitis c virus ...19938396675
a novel recombinant adenovirus vector expressing a flavivirus non-structural protein protects against lethal flavivirus challenge. 19938403779
mutagenesis of the yellow fever virus ns2b protein: effects on proteolytic processing, ns2b-ns3 complex formation, and viral replication.to study the role of specific regions of the yellow fever virus ns2b protein in proteolytic processing and association with the ns3 proteinase domain, a series of mutations were created in the hydrophobic regions and in a central conserved hydrophilic region proposed as a domain important for ns2b function. the effects of these mutations on cis cleavage at the 2b/3 cleavage site and on processing at other consensus cleavage sites for the ns3 proteinase in the nonstructural region were then chara ...19938411382
synthesis of dengue virus rna in vitro: initiation and the involvement of proteins ns3 and ns5.an assay for flavivirus rna-dependent rna polymerase activity in vitro was established using extracts of vero cells infected with dengue virus type 2 (den-2) or kunjin virus (kun). rna synthesis was initiated on a template of viral replicative form (rf) and rf was converted to the replicative intermediate (ri). the rna-dependent rna polymerase complex of den-2 utilised either den-2 or kun rf as template, and similarly the kun polymerase complex utilised either den-2 or kun rf template. in additi ...19938418788
mutagenesis of conserved residues at the yellow fever virus 3/4a and 4b/5 dibasic cleavage sites: effects on cleavage efficiency and polyprotein processing.flavivirus proteins are produced by co- and post-translational proteolytic processing of a large polyprotein using both host- and virus-encoded enzymes. the flavivirus serine proteinase, which consists of ns2b and ns3, is responsible for cleavages of at least four dibasic sites in the nonstructural region. in this study, a number of substitutions for the conserved amino acids flanking the 3/4a and 4b/5 dibasic cleavage sites [arg(p2)-arg(p1) decreases gly(p1')] were examined for their effects on ...19938421901
processing of the dengue virus type 2 proteins prm and c-prm.a glycoprotein c-prm of 35,000 m(r) was immuno-precipitated from lysates of aedes albopictus cells infected with dengue virus type 2 (den-2) using antisera directed against the c protein or an amino-terminal fragment of the prm glycoprotein. c-prm was not detected in infected vero cells. the prm glycoprotein synthesized in infected a. albopictus and vero cells was cleaved to produce the membrane-associated virion protein (m) and the non-m fragment (pr) immediately preceding or occurring simultan ...19938429301
proper maturation of the japanese encephalitis virus envelope glycoprotein requires cosynthesis with the premembrane protein.the role of the japanese encephalitis virus (jev) premembrane (prm) protein in maturation of the envelope (e) glycoprotein was evaluated by using recombinant vaccinia viruses encoding e in the presence (vp829) or absence (vp658) of prm. immunofluorescence analyses showed that e appeared to be localized in the endoplasmic reticulum of cells infected with jev, vp829, or vp658. however, reactivity with monoclonal antibodies and behavior in triton x-114 indicated that e produced in the absence of pr ...19938437237
cleavage at a novel site in the ns4a region by the yellow fever virus ns2b-3 proteinase is a prerequisite for processing at the downstream 4a/4b signalase site.flavivirus proteins are produced by co- and posttranslational proteolytic processing of a large polyprotein by both host- and virus-encoded proteinases. the viral serine proteinase, which consists of ns2b and ns3, is responsible for cleavage of at least four dibasic sites (2a/2b, 2b/3, 3/4a, and 4b/5) in the nonstructural region. since the amino acid sequence preceding ns4b shares characteristics with signal peptides used for translocation of nascent polypeptides into the lumen of the endoplasmi ...19938445732
dengue 2 virus ns2b and ns3 form a stable complex that can cleave ns3 within the helicase domain.flavivirus genomic rna is translated into a large polyprotein that is processed into structural and nonstructural proteins. the n-termini of several nonstructural proteins are produced by cleavage at dibasic sites by a two-component viral proteinase consisting of ns2b and ns3. ns3 contains a trypsin-like serine proteinase domain at its n-terminus, whereas the function of ns2b in proteolysis is yet to be determined. we have used an ns3-specific antiserum, under nondenaturing conditions, to demons ...19938460492
detection of west nile virus by the polymerase chain reaction and analysis of nucleotide sequence variation.a polymerase chain reaction (pcr) assay was developed to rapidly detect and identify west nile (wn) virus. the rna from seven isolates of wn virus from six countries and four other flaviviruses (kunjin, japanese encephalitis, st. louis encephalitis, and yellow fever viruses) was reverse-transcribed (rt) and amplified by pcr. the nucleotide sequences of the amplified products were determined by a rapid, automated dna sequencing method. the wn virus rt/pcr assay detected the target gene segment of ...19938470779
[in vitro suppression of translation of tick-borne encephalitis virus rna using antisense nucleotides].effect of antisense oligodeoxyribonucleotides on in vitro translation of rnas corresponding to fragments of the tick-borne encephalitis virus genome has been investigated. sequences optimal for oligonucleotide binding and translation arrest have been identified. the most efficient oligonucleotide (17-mer) at a concentration of 2.5 microm completely arrests translation of the rna coding for the ns3 protein.19938487765
nucleotide sequence of the envelope protein of a turkish isolate of tick-borne encephalitis (tbe) virus is distinct from other viruses of the tbe virus complex.turkish tick-borne encephalitis (tte) virus causes an acute form of meningoencephalomyelitis in sheep in the north-western region of turkey. the clinical syndrome resembles louping ill (li) and the viruses responsible for both li and tte are members of the tick-borne encephalitis (tbe) complex of the flaviviridae. the envelope protein gene of tte virus was reverse-transcribed, amplified, cloned and sequenced. alignment of the resultant sequence with those from other viruses of the tbe complex re ...19938492100
the fc portion of antibody to yellow fever virus ns1 is a determinant of protection against yf encephalitis in mice.the mechanism by which antibodies to the flavivirus nonvirion protein ns1 protect mice against encephalitis is unknown but their binding to cell surface ns1 raises the possibility of involvement of an fc piece-directed immune function. to investigate this, we prepared the f(ab')2 moiety of a protective igg2a monoclonal antibody (mab) against yellow fever virus (yf) ns1 and isolated igg2a- and igg2b-secreting isotype switch variants from a hybridoma that secretes a nonprotective igg1 anti-yf ns1 ...19938517015
regulation of the late events in flavivirus protein processing and maturation.in order to determine the requirements for secretion of flavivirus structural proteins, we analyzed the expression of several west nile flavivirus gene cassettes of different lengths in vaccinia virus expression systems. expression of the longest cassette coding for the 5'-nontranslated region, proteins c through ns2b, and the protease domain of ns3, resulted in secretion of prm-e complexes and cleavage of prm. the presence and proper processing of the ns2a-ns2b-ns3 region appeared to be necessa ...19938517028
west nile virus (flaviviridae:flavivirus) in experimentally infected argas ticks (acari:argasidae).to better define the possible role of argasid ticks in the epidemiology of west nile virus, adult argas arboreus, a. persicus, and a. hermanni were fed through a membrane on fetal bovine serum containing 10(5.5) 50% tissue culture infective doses (tcid50)/ml of west nile virus. the virus was detected for three and four days after feeding in a. persicus and a. hermanni, respectively. the virus titers then decreased to undetectable levels in both species. when the infective dose was increased to 1 ...19938517492
identification of two epitopes on the dengue 4 virus capsid protein recognized by a serotype-specific and a panel of serotype-cross-reactive human cd4+ cytotoxic t-lymphocyte clones.we analyzed the cd4+ t-lymphocyte response of a donor who had received an experimental live-attenuated dengue 4 virus (d4v) vaccine. bulk culture proliferative responses of peripheral blood mononuclear cells (pbmc) to noninfectious dengue virus (dv) antigens showed the highest proliferation to d4v antigen, with lesser, cross-reactive proliferation to d2v antigen. we established cd4+ cytotoxic t-lymphocyte clones (ctl) by stimulation with d4 antigen. using recombinant baculovirus antigens, we ide ...19968523518
[thymus hormones in the treatment and prevention of flavivirus infection under experimental conditions].the evaluation and selection of the preparations of thymic hormones for the treatment and prophylaxis of acute tick-borne encephalitis (tbe) caused by far eastern tbe virus strains have been carried out on mice under different experimental conditions. these virus strains, highly and faintly virulent with respect to noninbred mice, produce a different modulating effect of the immune responsiveness of the host, respectively suppressing or simulating immune response to sheep red blood cells. a high ...19958525716
purification and renaturation of japanese encephalitis virus nonstructural glycoprotein ns1 overproduced by insect cells.the nonstructural protein ns1 of japanese encephalitis virus is a major immunogen produced during flavivirus infection. however, the function of this protein has not been identified. to analyze its biochemical properties and evaluate its potential activity in the virus life cycle, the protein was produced in spodoptera frugiperda insect cells (sf9), using a recombinant baculovirus, and purified. as described previously by m. flamand, v. deubel, and m. girard (1992, virology 191, 826-836), a smal ...19958527939
australian-indonesian collaboration in veterinary arbovirology--a review.australian-indonesian collaboration in veterinary development programs has led to significant advances in the study of arboviruses. this paper reviews the resulting knowledge of arboviral infections of livestock in indonesia. the first recognized arboviral disease of animals in indonesia was bovine ephemeral fever. serology indicates that the virus is widespread, as are related rhabdoviruses. local sheep appear resistant to bluetongue disease, but imported sheep have suffered mortalities. blueto ...19958545953
australian x disease, murray valley encephalitis and the french connection.epidemics of a severe encephalitis occurred in eastern australia between 1917 and 1925, in which over 280 cases were reported with a fatality rate of 68%. the disease had not been described previously and was called australian x disease. the next epidemic occurred in south-east australia in the summer of 1950-51. the disease was given its name of murray valley encephalitis as this was the area from which most cases were reported. a virus was isolated by eric french in victoria, and about the sam ...19958545982
infectious transcripts of tick-borne encephalitis virus, generated in days by rt-pcr.construction of infectious clones of flaviviruses can be problematic owing to instability, toxicity, and recombination events occurring while cloning cdna in the bacterial vectors. to overcome these difficulties we have devised a rapid and simple method for producing an infectious genetically engineered tick-borne encephalitis virus in less than 10 days using viral rna from an unpurified virus suspension. the experimental protocol utilized the high fidelity reverse transcription-polymerase chain ...19958553563
[tick-transmitted arbovirus in maghreb].the problem of arbovirus infections in maghreb has been relatively neglected in the pst in spite of a rich diversity of biotopes, the presence of potential reservoirs and vectors, and their position on the flight path of the palearctic-african bird migration systems, western branch. moreover, west nile virus has been isolated from southern algeria since 1968. from 1979 to 1989, ticks were collected from wild birds, pigeons, bats, rodents, poultry, camels, wild boars, domestic mammals and man, an ...19958555772
evolutionary relationship of hepatitis c, pesti-, flavi-, plantviruses, and newly discovered gb hepatitis agents.two flavivirus-like viruses, gb virus-a (gbv-a) and gb virus-b (gbv-b), were recently identified in the gb hepatitis agent, and are distinct from the hepatitis a to e viruses. the putative helicase domain of gbv-a and gbv-b was found to have amino acid sequence homology with hepatitis c virus (hcv), and distantly, is also related to pestiviruses, flaviviruses, and plant viruses. a phylogenetic tree construction showed that gbvs and hcv are closely related, and they are clustered with pestiviruse ...19968557107
evolving virus plagues. 19968570592
population dynamics of flaviviruses revealed by molecular phylogenies.the phylogeny of 123 complete envelope gene sequences was reconstructed in order to understand the evolution of tick- and mosquito-borne flaviviruses. an analysis of phylogenetic tree structure reveals a continual and asymmetric branching process in the tick-borne flaviviruses, compared with an explosive radiation in the last 200 years in viruses transmitted by mosquitoes. the distinction between these two viral groups probably reflects differences in modes of dispersal, propagation, and changes ...19968570593
nucleotide sequence of the protein e gene of the tick-borne encephalitis virus strain 595 isolated in slovakia.tick-borne encephalitis (tbe) virus, strain 595 was isolated from ixodes ricinus ticks in southern slovakia. a part of the protein e gene was sequenced and compared with the prototype strain neudorfl. seventeen silent mutations and two amino acid changes (ile-->val, residue 167; asn-->thr, residue 366) were found. the nucleotide homology in the sequenced part of protein e gene of the strain 595 and the prototype strain neudorfl is 98.6%. these findings indicate that the strain 595 is closely rel ...19958578999
viral envelope glycoproteins swing into action.analysis of tick-borne encephalitis virus e protein reveals considerable structural diversity in the glycoproteins that clothe enveloped viruses and hints at the conformational gyrations in this molecule that lead to viral fusion.19958591041
advice for travelers. 19968598821
the diagnosis of wesselsbron disease in a new-born lamb by immunohistochemical staining of viral antigen.wesselsbron disease (wsl) was diagnosed in a 2-d-old lamb on a farm in the north-eastern free state province where a few abortions and neonatal deaths occurred in sheep in april 1994. the liver of the lamb was slightly swollen and orange-brown and, microscopically, it revealed single or small groups of necrotic hepatocytes that were randomly scattered throughout the lobules. other histopathologic hepatic lesions included the presence of acidophilic bodies, intranuclear inclusion bodies in a few ...19958600439
recombinant dengue type 1 virus ns5 protein expressed in escherichia coli exhibits rna-dependent rna polymerase activity.the complete nonstructural ns5 gene of dengue type 1 virus, singapore strain s275/90 (d1-s275/90) was expressed in escherichia coli as a glutathione s-transferase (gst) fusion protein (126 kda). the gst-ns5 fusion protein was purified and the recombinant ns5 protein released from the fusion protein by thrombin cleavage. the recombinant ns5 had a predicted molecular weight of 100 kda and reacted with antiserum against d1-s275/90 virus in western blot analysis. the purified recombinant ns5 protein ...19968607261
characterization and complete genome sequences of high- and low- virulence variants of tick-borne encephalitis virus.the entire genomic sequences of two strains (hypr and 263) of the flavivirus tick-borne encephalitis (tbe) virus differing in virulence from the prototypic strain neudoerfl were determined. strain hypr is a human isolate of tbe virus with a high laboratory passage history which exhibits a significantly higher neuro-invasiveness in mice compared to the prototype strain. strain 263 is a low-passage tick-isolate with a temperature-sensitive and attenuated phenotype. except for the heterogeneous 3' ...19968609469
molecular characterization of the japanese encephalitis serocomplex of the flavivirus genus.the japanese encephalitis (je) serocomplex of flaviviruses comprises 10 members, 9 of which: alfuy (alf); koutango (kou); kokobera (kok); kunjin (kun); murray valley encephalitis (mve); je; stratford (str); usutu (usu); and west nile (wn) have been isolated from africa, southern europe, middle east, asia, and australia. the tenth member, st. louis encephalitis (sle) virus, is confined to north, central, and south america. for alf, kok, kou, str, and usu, no sequence data have as yet been reporte ...19968610471
does gbv-c cause fulminant hepatitis in japan? 19968622432
molecular evidence for transmission of hepatitis g virus by blood transfusion. 19968622433
nitric oxide and viral infection: no antiviral activity against a flavivirus in vitro, and evidence for contribution to pathogenesis in experimental infection in vivo.upon stimulation murine macrophages produce high levels of nitric oxide (no), a potent microbicidal and tumoricidal agent recently also implicated as a mediator of antiviral defense. as dysregulated production of no may lead to extensive tissue damage, the production of this powerful mediator is tightly regulated. viral infection, however, may alter the regulation of certain macrophage functions, and recent work from our group demonstrated that viral infection--via induction of interferon-alpha ...19968623546
identification of amino acids involved in recognition by dengue virus ns3-specific, hla-dr15-restricted cytotoxic cd4+ t-cell clones.the majority of t-cell clones derived from a donor who experienced dengue illness following receipt of a live experimental dengue virus type 3 (den3) vaccine cross-reacted with all four serotypes of dengue virus, but some were serotype specific or only partially cross-reactive. the nonstructural protein, ns3, was immuno-dominant in the cd4+ t-cell response of this donor. the epitopes of four ns3-specific t-cell clones were analyzed. jk15 and jk13 recognized only den3 ns3, while jk44 recognized d ...19968627790
persistence and transmission of tick-borne viruses: ixodes ricinus and louping-ill virus in red grouse populations.the population dynamics of tick-borne disease agents and in particular the mechanisms which influence their persistence are examined with reference to the flavivirus that causes louping-ill in red grouse and sheep. pockets of infection cause heavy mortality and the infection probably persists as a consequence of immigration of susceptible hosts. seroprevalence is positively associated with temporal variations in vectors per host, although variation between areas is associated with the abundance ...19958632924
[new hepatitis viruses "e, gb, etc."].some cases of hepatitis were non a, non b, non c, non d. hepatitis e virus (calicivirus) transmission is fecal-oral similar to that of the hepatitis a virus. viral hepatitis e is endemic and frequently epidemic in many developing countries, but exceptionally observed in france. a high mortality rate was observed in pregnant women. recently, elisa assays for igm anti-hcv are available. many hepatitis cases (acute and chronic) are not caused by known viruses (non a-non e). four flavivirus like hav ...19968640310
pathogen-derived resistance to dengue type 2 virus in mosquito cells by expression of the premembrane coding region of the viral genome.the full-length premembrane (prm) coding region of the dengue virus type 2 (den-2; jamaica) genome was expressed in c6/36 (aedes albopictus) cells in either the sense or the antisense orientation from a double subgenomic sindbis (dssin) virus. northern (rna) blot analysis confirmed the expression of sense or antisense den-2 prm rna in infected c6/36 cells. prm protein was demonstrated in cells infected with dssin virus expressing den-2 sense rnas by an immunofluorescence assay. c6/36 cells were ...19968642634
cytokine regulation by virus infection: bovine viral diarrhea virus, a flavivirus, downregulates production of tumor necrosis factor alpha in macrophages in vitro.bovine bone marrow-derived macrophages were infected in vitro with noncytopathic or cytopathic strains of bovine viral diarrhea virus. infection with both biotypes resulted in a decreased production of tumor necrosis factor alpha upon stimulation with heat-inactivated salmonella dublin or lipopolysaccharide. other macrophage functions were not downregulated, indicating that the observed effect was not due to a loss in macrophage viability. the downregulated production of tumor necrosis factor al ...19968642701
rna binding properties of core protein of the flavivirus kunjin.kunjin virus (kun) c is a typical flavivirus core protein which is truncated in vivo to a mature form of 105 residues enriched in lysine and arginine. in order to study the possible association of kun c with rna in vitro, we prepared several recombinant c proteins with specific deletions, each fused at the amino-terminus to glutathione-s-transferase (gst) and expressed in e. coli. they were reacted with kun rna probes transcribed in vitro from cdna representing the 5' untranslated region (5' utr ...19968645104
immunisation with dna polynucleotides protects mice against lethal challenge with st. louis encephalitis virus.in vivo transfection by intramuscular injection with plasmids expressing the immunogenic proteins of microbial pathogens has considerable potential as a vaccination strategy against many pathogens of both man and animals. here we report that weanling mice given a single intramuscular injection of 50 micrograms of a plasmid, psle1 expressing the st. louis encephalitis virus (sle) prm/e protein under the control of the cytomegalovirus immediate early protein promoter produced sle-specific antibody ...19968645110
immunolocalization of the dengue virus nonstructural glycoprotein ns1 suggests a role in viral rna replication.although many workers have investigated the maturation and processing of the flavivirus nonstructural glycoprotein ns1 in infected cells, these studies have provided little insight into a possible function for ns1. in this study we investigated the subcellular localization of ns1 both by immunofluorescence and cryo-immuno electron microscopy of infected vero and c6/36 cells. ns1 was found to be tightly associated with intracellular membranes, in particular with vesicle packets and large cytoplas ...19968659120
hepatitis g virus in long-term survivors of haematological malignancy. 19968667905
evidence for the existence of a pseudoknot structure at the 3' terminus of the flavivirus genomic rna.the 3'-terminal nucleotides of the flavivirus genomic rna form conserved secondary structures that may function as cis-acting signals for rna replication. here we provide evidence for the existence of a conserved pseudoknot structure at the 3' terminus of the flavivirus genomic rna. a truncated version of the west nile virus (wnv) 3'-terminal rna sequence was used as the model for these studies. circular dichroism spectra indicated the presence of a highly structured rna conformation with a sign ...19968672458
recombinant subviral particles from tick-borne encephalitis virus are fusogenic and provide a model system for studying flavivirus envelope glycoprotein functions.recombinant subviral particles (rsps) obtained by coexpression of the envelope (e) and premembrane (prm) proteins of tick-borne encephalitis virus in cos cells (s. l. allison, k. stadler, c. w. mandl, c. kunz, and f. x. heinz, j. virol. 69:5816-5820, 1995) were extensively characterized and shown to be ordered structures containing envelope glycoproteins with structural and functional properties very similar to those in the virion envelope. the particles were spherical, with a diameter of about ...19968676481
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