Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
japanese encephalitis vaccines: current vaccines and future prospects.vaccination against je ideally should be practiced in all areas of asia where the virus is responsible for human disease. the who has placed a high priority on the development of a new vaccine for prevention of je. some countries in asia (japan, south korea, north korea, taiwan, vietnam, thailand, and the prc) manufacture je vaccines and practice childhood immunization, while other countries suffering endemic or epidemic disease (india, nepal, laos, cambodia, bangladesh, myanmar, malaysia, indon ...200212082985
host genetic resistance to japanese encephalitis group viruses. 200212082988
the emergence of west nile virus in north america: ecology, epidemiology, and surveillance.in late summer 1999, the first domestically acquired human cases of wn encephalitis were documented in the usa. aggressive vector-control and public education efforts by state and local public health officials limited the extent of human involvement. the discovery of virus-infected, overwintering mosquitoes during the winter of 1999-2000, predicted renewed virus activity for the following spring, and prompted early season vector-control activities and disease surveillance efforts in nyc and the ...200212082991
evolution of the japanese encephalitis serocomplex viruses. 200212082999
japanese encephalitis as an emerging virus: the emergence and spread of japanese encephalitis virus in australasia. 200212083000
immune responses to japanese encephalitis virus. 200212083002
emergence of usutu virus, an african mosquito-borne flavivirus of the japanese encephalitis virus group, central europe.during late summer 2001 in austria, a series of deaths in several species of birds occurred, similar to the beginning of the west nile virus (wnv) epidemic in the united states. we necropsied the dead birds and examined them by various methods; pathologic and immunohistologic investigations suggested a wnv infection. subsequently, the virus was isolated, identified, partially sequenced, and subjected to phylogenetic analysis. the isolates exhibited 97% identity to usutu virus (usuv), a mosquito- ...200212095429
the interdomain region of dengue ns5 protein that binds to the viral helicase ns3 contains independently functional importin beta 1 and importin alpha/beta-recognized nuclear localization signals.dengue virus ns5 protein is a multifunctional rna-dependent rna polymerase that is essential for virus replication. we have shown previously that the 37- amino acid interdomain spacer sequence (residues (369)x(2)kkx(14)kkkx(11)rkx(3)405) of dengue2 ns5 contains a functional nuclear localization signal (nls). in this study, beta-galactosidase fusion proteins carrying point mutations of the positively charged residues or truncations of the interdomain linker region (residues 369-389 or residues 38 ...200212105224
st. louis encephalitis virus induced pathology in cultured cells.apoptosis is a highly regulated process of cellular self-destruction with diverse functions in multicellular organisms. it is known to be one of the mechanisms of viral pathogenesis. st. louis encephalitis virus (slev), an arthropod-borne flavivirus, causes encephalitis disease of varying severity mostly in north america and in some regions of south america. this virus induces cytopathic effects in vertebrate cell lines, however, the mechanism by which this occurs is yet to be elucidated. slev i ...200212111422
complete genome sequence of montana myotis leukoencephalitis virus, phylogenetic analysis and comparative study of the 3' untranslated region of flaviviruses with no known vector.montana myotis leukoencephalitis virus (mmlv), a virus isolated from bats, causes an encephalitis in small rodents reminiscent of flavivirus encephalitis in humans. the complete mmlv genome is 10690 nucleotides long and encodes a putative polyprotein of 3374 amino acids. the virus contains the same conserved motifs in genes that are believed to be interesting antiviral targets (ntpase/helicase, serine protease and rna-dependent rna polymerase) as flaviviruses of clinical importance. phylogenetic ...200212124451
infection of scid mice with montana myotis leukoencephalitis virus as a model for flavivirus encephalitis.we have established a convenient animal model for flavivirus encephalitis using montana myotis leukoencephalitis virus (mmlv), a bat flavivirus. this virus has the same genomic organization, and contains the same conserved motifs in genes that encode potential antiviral targets, as flaviviruses that cause disease in man (n. charlier et al., accompanying paper), and has a similar particle size (approximately 40 nm). mmlv replicates well in vero cells and appears to be equally as sensitive as yell ...200212124452
seasonal abundance of culex nigripalpus theobald and culex salinarius coquillett in north florida, usa.north florida is a transition zone between widespread culex nigripalpus populations to the south and focal culex salinarius populations to the north. culex nigripalpus is a vector of st. louis encephalitis (sle) and eastern equine encephalitis (eee) viruses in south florida, while cx. salinarius is a suspected new world vector of west nile (wn) virus. abundant vector populations are often a prerequisite for epidemic and epizootic transmission of arboviruses. extensive sle transmission has never ...200212125867
etiology of encephalitis syndrome among hospitalized children and adults in takeo, cambodia, 1999-2000.whether or not japanese encephalitis virus (jev) is an important causative agent of acute encephalitis in cambodia remains unclear. this study was carried out to determine the cause of encephalitis syndrome among children and adults admitted to takeo provincial hospital from october 1999 to september 2000. ninety-nine cases were included in the study: 52 pediatric cases (12 were fatal) and 47 adult cases (10 were fatal). a causative agent such as human herpesvirus (hhv-3 or hhv-4), cryptococcus ...200212135294
catalytically active dengue virus ns3 protease forms aggregates that are separable by size exclusion chromatography.an active form of the dengue virus protease ns3 (cf40.gly.ns3pro) was expressed in escherichia coli. this construct consists of a critical 40 amino acid cofactor domain from ns2b fused to the n-terminal 184 amino acid protease domain of ns3 via a flexible, covalent linker (gly(4)sergly(4)). the recombinantly produced protein is soluble and has a hexa-histidine tag engineered at the n-terminus for ease of purification using metal affinity chromatography. however, the presence of lower molecular w ...200212135556
safety and immunogenicity of tetravalent live-attenuated dengue vaccines in thai adult volunteers: role of serotype concentration, ratio, and multiple doses.dengue fever, caused by four serotypes of a mosquito-borne virus, is a growing problem in tropical countries. currently, there is no treatment or vaccine. we evaluated safety and immunogenicity of two doses, given six months apart, of seven formulations of dengue tetravalent live-attenuated vaccine (containing different concentrations of the component viruses) versus placebo in 59 flavivirus-seronegative thai adults. the first dose was the more reactogenic. most volunteers experienced clinically ...200212139219
tick-borne encephalitis (tbe) in dogs.tick-borne encephalitis (tbe) is caused by a flavivirus and transmitted by ticks. it is known in dogs for nearly 30 years and the number of tbe cases is increasing. in addition to fever, cerebrocortical, thalamic, and brainstem symptoms occur simultaneously. not all tbe infections in dogs lead to clinical signs but peracute/lethal as well as subacute and chronic courses have been reported. tbe is a seasonal disease, depending on climate related tick activity. infected ticks are spreading the vir ...200212141763
the molecular biology of west nile virus: a new invader of the western hemisphere.west nile virus (wnv) is a mosquito-borne flavivirus that primarily infects birds but occasionally also infects humans and horses. in recent years, the frequency of wnv outbreaks in humans has increased, and these outbreaks have been associated with a higher incidence of severe disease. in 1999, the geographical distribution of wnv expanded to the western hemisphere. wnv has a positive strand rna genome of about 11 kb that encodes a single polyprotein. wnv replicates in the cytoplasm of infected ...200212142476
modes of transmission of hemorrhagic fever. 200212150658
expression, purification, and characterization of the rna 5'-triphosphatase activity of dengue virus type 2 nonstructural protein 3.dengue virus type 2 (den2), a member of the flaviviridae family of positive-strand rna viruses, contains a single rna genome having a type i cap structure at the 5' end. the viral rna is translated to produce a single polyprotein precursor that is processed to yield three virion proteins and at least seven nonstructural proteins (ns) in the infected host. ns3 is a multifunctional protein having a serine protease catalytic triad within the n-terminal 180 amino acid residues which requires ns2b as ...200212167347
a nonsense mutation in the gene encoding 2'-5'-oligoadenylate synthetase/l1 isoform is associated with west nile virus susceptibility in laboratory mice.a mouse model has been established to investigate the genetic determinism of host susceptibility to west nile (wn) virus, a member of the genus flavivirus and family flaviviridae. whereas wn virus causes encephalitis and death in most laboratory inbred mouse strains after peripheral inoculation, most strains derived from recently trapped wild mice are completely resistant. the phenotype of resistance/susceptibility is determined by a major locus, wnv, mapping to chromosome 5 within the 0.4-cm-wi ...200212186974
west nile virus.west nile (wn) virus is a mosquito-borne flavivirus and human, equine, and avian neuropathogen. the virus is indigenous to africa, asia, europe, and australia, and has recently caused large epidemics in romania, russia, and israel. birds are the natural reservoir (amplifying) hosts, and wn virus is maintained in nature in a mosquito-bird-mosquito transmission cycle primarily involving culex sp mosquitoes. wn virus was recently introduced to north america, where it was first detected in 1999 duri ...200212206968
classical swine fever virus ns5b-gfp fusion protein possesses an rna-dependent rna polymerase activity.rna-dependent rna polymerase (rdrp) is the replicase of positive-strand rna viruses. expression and characterization of the replicase are the first steps in the elucidation of the virus replication mechanism. we expressed nonstructural protein 5b (ns5b) of classical swine fever virus (csfv) as a fusion protein with green fluorescent protein (gfp) in porcine kidney cells (pk-15 cells), natural host cells of csfv. the expressed csfv ns5b-gfp fusion protein possessed rdrp activity. by fluorescence ...200212209316
antibodies against prm protein distinguish between previous infection with dengue and japanese encephalitis viruses.in southeast asia, dengue viruses often co-circulate with other flaviviruses such as japanese encephalitis virus, and due to the presence of shared antigenic epitopes it is often difficult to use serological methods to distinguish between previous infections by these flaviviruses.200212019028
t cell responses to an hla-b*07-restricted epitope on the dengue ns3 protein correlate with disease severity.dengue hemorrhagic fever (dhf), the severe manifestation of dengue virus (dv) infection characterized by plasma leakage, is more common in secondary dv infections in previously infected individuals and is associated with high levels of immune activation. to determine the ag specificity of this immune response, we studied the response to an hla-b*07-restricted t cell epitope, residues 221-232 of the dv ns3 protein, in 10 hla-b*07(+) thai children who were studied during and after acute dv infecti ...200212023403
fatal yellow fever in a traveler returning from amazonas, brazil, 2002. 200212025823
an rna cap (nucleoside-2'-o-)-methyltransferase in the flavivirus rna polymerase ns5: crystal structure and functional characterization.viruses represent an attractive system with which to study the molecular basis of mrna capping and its relation to the rna transcription machinery. the rna-dependent rna polymerase ns5 of flaviviruses presents a characteristic motif of s-adenosyl-l-methionine-dependent methyltransferases at its n-terminus, and polymerase motifs at its c-terminus. the crystal structure of an n-terminal fragment of dengue virus type 2 ns5 is reported at 2.4 a resolution. we show that this ns5 domain includes a typ ...200212032088
antiviral effects of an iminosugar derivative on flavivirus infections.endoplasmic reticulum (er) alpha-glucosidase inhibitors, which block the trimming step of n-linked glycosylation, have been shown to eliminate the production of several er-budding viruses. here we investigated the effects of one such inhibitor, n-nonyl-deoxynojirimycin (nn-dnj), a 9-carbon alkyl iminosugar derivative, on infection by japanese encephalitis virus (jev) and dengue virus serotype 2 (den-2). in the presence of nn-dnj, jev and den-2 infections were suppressed in a dose-dependent manne ...200211907199
membrane interactions of the tick-borne encephalitis virus fusion protein e at low ph.membrane fusion of the flavivirus tick-borne encephalitis virus is triggered by the mildly acidic ph of the endosome and is mediated by envelope protein e, a class ii viral fusion protein. the low-ph trigger induces an oligomeric rearrangement in which the subunits of the native e homodimers dissociate and the monomeric subunits then reassociate into homotrimers. here we provide evidence that membrane binding is mediated by the intermediate monomeric form of e, generated by low-ph-induced dissoc ...200211907218
kunjin virus replicon vaccine vectors induce protective cd8+ t-cell immunity.the ability of self-replicating rna (replicon) vaccine vectors derived from the australian flavivirus kunjin (kun) to induce protective alphabeta cd8+ t-cell responses was examined. kun replicons encoding a model immunogen were delivered by three different vaccine modalities: (i) as naked rna transcribed in vitro, (ii) as plasmid dna constructed to allow in vivo transcription of replicon rna by cellular rna polymerase ii (dna based), and (iii) as replicon rna encapsidated into virus-like particl ...200211907219
immunization with heterologous flaviviruses protective against fatal west nile encephalitis.prior immunization of hamsters with three heterologous flaviviruses (japanese encephalitis virus [jev] sa14-2-8 vaccine, wild-type st. louis encephalitis virus [slev], and yellow fever virus [yfv] 17d vaccine) reduces the severity of subsequent west nile virus (wnv) infection. groups of adult hamsters were immunized with each of the heterologous flaviviruses; approximately 30 days later, the animals were injected intraperitoneally with a virulent new york strain of wnv. subsequent levels of vire ...200211927020
structural surprises from the flaviviruses and alphaviruses.recent structural studies demonstrate that the alphavirus and flavivirus fusion proteins, although very similar in overall fold, are arranged very differently in the two virions. these differences raise many interesting questions about virus assembly and fusion activity.200211931753
the pathogenicity of louping ill virus for mice and lambs.mice and lambs were infected with the li/i, li/31 or ma54 strain of louping ill virus (liv) to provide information relevant to testing the efficacy and biosafety of a new generation of flavivirus vaccines based on a semliki forest virus (sfv) vector. whereas clinical signs and neuropathological lesions were consistently severe in mice, the majority of lambs showed lesions of moderate severity and only lambs with severe lesions were clinically affected. for both species, dispersal of viral antige ...200211945002
flavivirus susceptibility in aedes aegypti.aedes aegypti is the primary vector of yellow fever (yf) and dengue fever (df) flaviviruses worldwide. in this review we focus on past and present research on genetic components and environmental factors in aedes aegypti that appear to control flavivirus transmission. we review genetic relationships among ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. we describe current research into h ...200212234528
infection of polarized epithelial cells with flavivirus west nile: polarized entry and egress of virus occur through the apical surface.both polarized epithelial vero (c1008) and non-polarized vero (control) cells were grown on permeable cell culture inserts and infected either apically or basolaterally with west nile (wn) or kunjin (kun) virus. kun virus (closely related to wn virus) was used as a comparison. using indirect immunofluorescence and plaque assays of productive virus titres, entry of wn and kun viruses was confined to the apical surface of polarized epithelial cells. for the first time, these results provided evide ...200212237424
genome sequence analysis of tamana bat virus and its relationship with the genus flavivirus.tamana bat virus (tabv, isolated from the bat pteronotus parnellii) is currently classified as a tentative species in the genus flavivirus: we report here the determination and analysis of its complete coding sequence. low but significant similarity scores between tabv and member-viruses of the genus flavivirus were identified in the amino acid sequences of the structural, ns3 and ns5 genes. a series of cysteines located in the envelope protein and the most important enzymatic domains of the vir ...200212237426
in vitro determination of dengue virus type 2 ns2b-ns3 protease activity with fluorescent peptide substrates.the ns2b-ns3(pro) polyprotein segment from the dengue virus serotype 2 strain 16681 was purified from overexpressing e. coli by metal chelate affinity chromatography and gel filtration. enzymatic activity of the refolded ns2b-ns3(pro) protease complex was determined in vitro with dansyl-labeled peptide substrates, based upon native dengue virus type 2 cleavage sites. the 12mer substrate peptides and the cleavage products could be separated by reversed-phase hplc, and were identified by uv and fl ...200212297031
effect of triethylamine on the recovery of selected south american alphaviruses, flaviviruses, and bunyaviruses from mosquito (diptera: culicidae) pools.we evaluated the effect of triethylamine (tea) on the recovery of infectious virus from pools of mosquitoes for two south american alphaviruses (eastern equine encephalomyelitis and venezuelan equine encephalomyelitis subtypes iiic and id), one flavivirus (ilheus) and two bunyaviruses (mirim [guama group] and itaqui [group c]). mosquitoes were inoculated intrathoracically with virus, held for 7-10 d at 26 degrees c, and handled under one of four regimens before testing for the presence of virus ...200212349865
complementation analysis of the flavivirus kunjin ns3 and ns5 proteins defines the minimal regions essential for formation of a replication complex and shows a requirement of ns3 in cis for virus assembly.we have previously reported successful trans-complementation of defective kunjin virus genomic rnas with a range of large lethal deletions in the nonstructural genes ns1, ns3, and ns5 (a. a. khromykh et al., j. virol. 74:3253-3263, 2000). in this study we have mapped further the minimal region in the ns5 gene essential for efficient trans-complementation of genome-length rnas in repbhk cells to the first 316 of the 905 codons. to allow amplification and easy detection of complemented defective r ...200212368319
epizootic activity of murray valley encephalitis virus in an aboriginal community in the southeast kimberley region of western australia: results of cross-sectional and longitudinal serologic studies.murray valley encephalitis (mve) virus is a mosquito-borne flavivirus causing severe encephalitis with a resultant high morbidity and mortality. in the period 1989-1993, we undertook a cross-sectional and longitudinal study by annually screening members of a small remote aboriginal community in northwestern australia for mve virus antibodies. of the estimated 250-300 people in the community, 249 were tested, and 52.6% had positive serology to mve. the proportion testing positive increased with i ...200212408675
characterization and e protein expression of mutant strains during persistent infection of kn73 cells with japanese encephalitis virus.to study the character of mutants originating from japanese encephalitis viruses and the relationship between the characterization of mutant strains and e protein expression.200212411104
sentinel chicken surveillance programme in australia, 1 july 2001 to 30 june 2002.detection of flavivirus seroconversions in sentinel chicken flocks located throughout australia is used to provide an early warning of increased levels of murray valley encephalitis (mve) and kunjin virus activity in the region. during the 2001/2002 season low levels of flavivirus activity were detected in northern australia compared to previous years. mve and kunjin virus activity was detected in the kimberley and pilbara regions of western australia and the northern territory but not in north ...200212416705
reactivity of serum samples from patients with a flavivirus infection measured by immunofluorescence assay and elisa.flavivirus infections are a significant public health problem, since several members of the flaviviridae family are highly pathogenic to humans. accurate diagnosis and differentiation of the infecting virus is important, especially in areas where many flaviviruses are circulating. in this study we evaluated a newly developed commercially available immunofluorescence assay (ifa) (indx, baltimore, md, usa) for the detection of igm and igg antibodies against dengue virus, yellow fever virus, japane ...200212467761
the epidemiology of yellow fever in africa.yellow fever (yf) is still a major public heath problem, particularly in africa, despite the availability of a very efficacious vaccine. the world health organization estimates that there are 200,000 cases of yf annually, including 30,000 deaths, of which over 90% occur in africa. in the past 15 years, the number of yf cases has increased tremendously, with most of the yf activity in west africa. this increase in yf activity is in part due to a breakdown in yf vaccination and mosquito control pr ...200212475636
novelity in gb virus c/hepatitis g virus and its controversy.several novel human rna viruses were identified in 1995-96 and were partially characterized that apparently can cause acute and chronic hepatitis both in monkeys and humans. these new viruses are related to the flavivirus hepatitis c. it is known to be distinct from other human hepatitis viruses (a, b, c, d, e). three viruses, identified by investigators at abbott labs, have been termed gb-a, gb-b and gb-c. gb-a and gb-b are likely tamarin viruses whereas gb-c infects humans only. all these thre ...200212476863
strategies for the identification of inhibitors of west nile virus and other flaviviruses.the recent outbreaks of west nile virus (wnv) and other emerging and re-emerging flaviviruses, have made prevention and treatment of flavivirus infections a global public health priority. no inhibitor is currently available for use as an antiflavivirus therapy. in this communication, i review (i) stages of flavivirus replication representing potential targets for antiviral drug discovery; (ii) strategies for identification of flavivirus inhibitors; and (iii) existing antiviral inhibitors reporte ...200212476954
poly i:clc induction of the interferon system in mice: an initial study of four detection methods.induction of a large number of the components of the interferon (ifn) system (ifn genes, their mrnas, ifn proteins, ifn receptors, ifn signaling molecules, the ifn response genes, and their effector proteins) has been studied. less well studied is the comparative induction of these components in vivo. induction of ifn by double-stranded rna (dsrna) treatment mimics certain aspects of viral infection and induces the components of the ifn system. to determine the comparative sensitivity of detecti ...200212433283
requirements for de novo initiation of rna synthesis by recombinant flaviviral rna-dependent rna polymerases.rna-dependent rna polymerases (rdrps) that initiate rna synthesis by a de novo mechanism should specifically recognize the template initiation nucleotide, t1, and the substrate initiation nucleotide, the ntpi. the rdrps from hepatitis c virus (hcv), bovine viral diarrhea virus (bvdv), and gb virus-b all can initiate rna synthesis by a de novo mechanism. we used rnas and gtp analogs, respectively, to examine the use of the t1 nucleotide and the initiation nucleotide (ntpi) during de novo initiati ...200212438578
prevalence of hepatitis g virus infection and homology of different viral strains in southern china.to investigate the prevalence of hepatitis g virus (hgv) infection and to analyse the homology of different hgv strains in southern china.200212439930
ratios of subclinical to clinical japanese encephalitis (je) virus infections in vaccinated populations: evaluation of an inactivated je vaccine by comparing the ratios with those in unvaccinated populations.japanese encephalitis (je) virus is characterized as a virus that produces a large number of subclinical infections. in this report, we estimated a ratio of subclinical to clinical infections in vaccinated human populations who acquired natural infection with je virus, and evaluated protective capacity of the currently approved inactivated je vaccine by comparing the ratio with those reported for unvaccinated populations. we developed a sensitive immunostaining method for detecting nonstructural ...200212443667
prevalence of gb virus c/hepatitis g virus in hungary.in 1995 a new flavivirus, gb virus c/hepatitis g virus (gbv-c/hgv), was discovered. the aim of this study was to determine the prevalence of the virus in healthy persons and hepatitis patients in hungary. the sera of 408 healthy persons older than 60 years were tested for the presence of gbv-c/hgv antibodies, and 113 were positive (28%). eight of the 71 healthy persons younger than 60 years and twenty of the 51 sera (39%) taken from patients suffering from hepatitis of unknown origin proved to b ...200212443828
single mutation in the flavivirus envelope protein hinge region increases neurovirulence for mice and monkeys but decreases viscerotropism for monkeys: relevance to development and safety testing of live, attenuated vaccines.a chimeric yellow fever (yf) virus/japanese encephalitis (je) virus vaccine (chimerivax-je) was constructed by insertion of the prm-e genes from the attenuated je virus sa14-14-2 vaccine strain into a full-length cdna clone of yf 17d virus. passage in fetal rhesus lung (frhl) cells led to the emergence of a small-plaque virus containing a single met-->lys amino acid mutation at e279, reverting this residue from the sa14-14-2 to the wild-type amino acid. a similar virus was also constructed by si ...200211799188
clinical proof of principle for chimerivax: recombinant live, attenuated vaccines against flavivirus infections.chimerivax is a live, attenuated recombinant virus constructed from yellow fever (yf) 17d in which the envelope protein genes of yf 17d are replaced with the corresponding genes of another flavivirus. a chimerivax vaccine was developed against japanese encephalitis (je). a randomized, double-blind, outpatient study was conducted to compare the safety and immunogenicity of chimerivax-je and yf 17d. six yf immune and six non-immune adults were randomized to receive a single sc inoculation of chime ...200211803060
sequence diversity of the capsid gene and the nonstructural gene ns2b of dengue-3 virus in vivo.previously, we studied the envelope (e) gene of dengue virus and reported that dengue-3 virus is present as a quasispecies. to investigate the extent of intrahost sequence variation of other dengue viral genes, we examined in this study the capsid (c) gene and the nonstructural gene, ns2b, derived directly from plasma dengue viruses from 18 confirmed dengue-3 patients. using reverse transcription-pcr, multiple clones of a 360-nucleotide region covering the c gene and of a 404-nucleotide region c ...200212482670
hepatitis g virus (hgv): current perspectives.five viruses are usually associated with hepatitis in humans: a-e. in addition to these viruses as aetiological agents of hepatitis, there remain a number of patients with hepatitis in whom no virus could be identified. it was therefore postulated that there may be other agents which may be causing hepatitis. recently, two viruses have been associated with hepatitis: hepatitis g virus (hgv), and transfusion transmissible virus (ttv). hepatitis g virus (hgv) is a single stranded rna virus which r ...200212593580
laboratory-acquired west nile virus infections--united states, 2002.west nile virus (wnv), a mosquito-borne flavivirus introduced recently to north america, is a human, equine, and avian neuropathogen. the majority of human infections with wnv are mosquito-borne; however, laboratory-acquired infections with wnv and other arboviruses also occur. this report summarizes two recent cases of wnv infection in laboratory workers without other known risk factors who acquired infection through percutaneous inoculation. laboratory workers handling fluids or tissues known ...200212537288
intrauterine west nile virus infection--new york, 2002.west nile virus (wnv), a mosquito-borne flavivirus and human neuropathogen, is epidemic in the united states. in 2002, newly recognized mechanisms of person-to-person wnv transmission were described, including possible transmission from mother to infant through breast milk. wnv has not been previously associated with intrauterine infection or adverse birth outcomes. this report describes a case of transplacental wnv transmission. pregnant women should take precautions to reduce their risk for wn ...200212537289
new inferences from tree shape: numbers of missing taxa and population growth rates.the relative positions of branching events in a phylogeny contain information about evolutionary and population dynamic processes. we provide new summary statistics of branching event times and describe how these statistics can be used to infer rates of species diversification from interspecies trees or rates of population growth from intraspecies trees. we also introduce a phylogenetic method for estimating the level of taxon sampling in a clade. different evolutionary models and different samp ...200212554454
remotely sensed correlates of phylogeny: tick-borne flaviviruses.vector-borne pathogen systems are limited by climate, principally through its impact on the distribution, abundance and population dynamics of the vectors and on the interaction of vectors with their hosts. this leads to the prediction that climate has been a significant factor in the evolution of these pathogens and, by implication, will be important in future events on both evolutionary and ecological time-scales. new phylogenetic trees of organisms, that describe their evolutionary history, a ...200214570136
mycophenolic acid inhibits dengue virus infection by preventing replication of viral rna.dengue fever is a mosquito-borne viral disease of global importance with no available antiviral therapy. we assessed the ability of mycophenolic acid (mpa), a drug currently used as an immunosuppressive agent, to inhibit dengue virus (dv) antigen expression, rna replication, and virus production. pharmacological concentrations of mpa effectively blocked dv infection, decreasing the percentage of infected cells by 99% and the levels of secreted virus by up to a millionfold. results were reproduce ...200212504563
a new cell line from the embryonic tissues of culex tritaeniorhynchus and its susceptibility to certain flaviviruses.a new cell line from the embryonic tissue of culex tritaeniorhynchus mosquito was established. morphological studies carried out at the 45th passage level (p-45) showed four different cell types viz. epithelial-like cells, fibroblast-like cells, giant cells and vacuolated cells. karyological studies indicated diploid (2n = 6) chromosomes in majority of cells irrespective of passage level. a twelve-fold increase of cell number was observed in 10 days at p-49. the cells could be preserved in liqui ...200212693860
architecture of the flaviviral replication complex. protease, nuclease, and detergents reveal encasement within double-layered membrane compartments.flavivirus infection causes extensive proliferation and reorganization of host cell membranes to form specialized structures called convoluted membranes/paracrystalline arrays and vesicle packets (vp), the latter of which is believed to harbor flaviviral replication complexes. using detergents and trypsin and micrococcal nuclease, we provide for the first time biochemical evidence for a double membrane compartment that encloses the replicative form (rf) rna of the three pathogenic flaviviruses w ...200312700232
stable rna structures can repress rna synthesis in vitro by the brome mosaic virus replicase.a 15-nucleotide (nt) unstructured rna with an initiation site but lacking a promoter could direct the initiation of rna synthesis by the brome mosaic virus (bmv) replicase in vitro. however, bmv rna with a functional initiation site but a mutated promoter could not initiate rna synthesis either in vitro or in vivo. to explain these two observations, we hypothesize that rna structures that cannot function as promoters could prevent rna synthesis by the bmv rna replicase. we documented that four d ...200312702814
role of heparan sulfate for attachment and entry of tick-borne encephalitis virus.attachment of the flavivirus tick-borne encephalitis (tbe) virus to different permissive cell lines was investigated by a newly established quantitative assay using fluorescence-labeled virus. previous work had shown that bhk-21 cell-adapted mutants of tbe virus had acquired potential heparan sulfate (hs) binding sites on the outer surface of protein e. quantitative analysis of one of these mutants indicated that it attached to hs-expressing cell lines with a 10- to 13-fold higher affinity than ...200312706093
recent advances in japanese encephalitis.japanese encephalitis (je), the most important cause of epidemic encephalitis worldwide, is confined to asia, but its geographical area is spreading. west nile virus, and other closely related flaviviruses, cause similar disease elsewhere. recent cryoelectron microscopic studies have characterized the flavivirus envelope protein as a new class of viral fusion protein (class ii), and examined its arrangement on the virion surface. changes in the envelope protein's hinge region, or its putative re ...200312707858
serologic evidence of west nile virus infection in black bears (ursus americanus) from new jersey.serum samples obtained from 51 free-ranging black bears (ursus americanus) in northwestern new jersey in february and march 2002 were analyzed for neutralizing antibodies to west nile virus (wnv) and st. louis encephalitis virus. three (6%) of the black bears tested positive for wnv-neutralizing antibodies. one additional sample was positive for flavivirus-neutralizing antibodies but could not be differentiated for a specific virus type. this is the first report of wnv infection in black bears.200314733286
serologic evidence of west nile virus infection in birds, tamaulipas state, méxico.following the introduction of west nile virus (wnv) into north america in 1999, surveillance for wnv in migratory and resident birds was established in tamaulipas state, northern méxico in december 2001. overall, 796 birds representing 70 species and 10 orders were captured and assayed for antibodies to wnv. nine birds had flavivirus-specific antibodies by epitope-blocking enzyme-linked immunosorbent assay; four were confirmed to have antibody to wnv by plaque reduction neutralization test. the ...200314733673
[the alkhurma virus (family flaviviridae, genus flavivirus): an emerging pathogen responsible for hemorrhage fever in the middle east].to date tick-borne flaviviruses causing hemorrhagic fevers in humans have been isolated in siberia (omsk hemorrhagic fever virus), india (kyasanur forest disease virus), and saudi arabia (akhurma virus). because of their potential use as biological weapons for bioterrorism, these 3 viruses require level 4 biosafety handling facilities and have been listed as hypervirulent pathogens by the center for disease control and prevention. alkhurma virus was isolated in 1995 from patients with hemorrhagi ...200314579470
evolutionary relationship between old world west nile virus strains. evidence for viral gene flow between africa, the middle east, and europe.little is known about the genetic relationships between european and other old-world strains of west nile virus (wnv) and persistence of wnv north of mediterranean. we characterized the complete genomes of three wnv strains from france (horse-2000), tunisia (human-1997) and kenya (mosquito-1998), and the envelope, ns3 and ns5 genes of the koutango virus. phylogenetic analyses including all available full-length sequences showed that: (1) koutango virus is a distant variant of wnv; (2) the three ...200314585341
activation of dengue protease autocleavage at the ns2b-ns3 junction by recombinant ns3 and gst-ns2b fusion proteins.dengue virus possesses a protease complex made up of the non-structural proteins ns2b and ns3. this protease complex catalyzes autocleavage (cis) at the junction between ns2a and ns2b as well as between ns2b and ns3. it also catalyzes trans cleavage at the junctions between ns3 and ns4a as well as ns4b and ns5. the cis cleavage at the ns2b-ns3 junction has been demonstrated in escherichia coli by linking a 40-residue hydrophilic segment of ns2b to a ns3 n-terminal protease domain carrying the ns ...200314599678
a blunted blood plasmacytoid dendritic cell response to an acute systemic viral infection is associated with increased disease severity.at least two distinct human dendritic cell (dc) subsets are produced in the bone marrow and circulate in the peripheral blood-precursor myeloid dcs (pre-mdcs) and plasmacytoid dcs (pdcs). both lineages of dcs are instrumental in antiviral innate immunity and shaping th1 adaptive immune responses. pdcs are the most potent ifn-alpha-producing cells to viral pathogens. dengue, an acute flavivirus disease, provides a model to study dc responses to a self-limited human viral infection. we analyzed ci ...200314607965
[application of one step rt-pcr assay for detection of flavivirus rna in mosquitoes].the conditions of one step rt-pcr method for detection of virus rna in field-collected mosquitoes, and preservation period of infected mosquitoes for one step rt-pcr were examined. we compared several virus rna extraction methods with artificially contaminated mosquito pools with dengue virus (dv), japanese encephalitis virus (jev), and yellow fever virus (yfv) with a known amount of plaque forming unit (pfu) to establish the condition of one step rt-pcr. in this study, most effective rna extrac ...200314608915
inhibition of interferon signaling by dengue virus.dengue virus is a worldwide-distributed mosquito-borne flavivirus with a positive strand rna genome. its transcribed polyprotein is cleaved by host- and virus-encoded peptidases into 10 proteins, some of which are of unknown function. although dengue virus-infected cells seem to be resistant to the antiviral action of ifn, the viral products that mediate this resistance are unknown. therefore, we have analyzed the ability of the 10 dengue virus-encoded proteins to antagonize the ifn response. we ...200314612562
gb virus type c/hepatitis g virus: a non-pathogenic flavivirus associated with prolonged survival in hiv-infected individuals.gb virus c (gbv-c) is a common virus that does not appear to cause disease. gbv-c persists in up to 50% of exposed individuals, and virus replication appears to be in lymphocytes including cd4+ t cells. gbv-c infection is common among hiv-positive people, and several studies have found that hiv-positive individuals co-infected with gbv-c survive for statistically significantly longer periods of time than people without gbv-c. in vitro studies suggest that gbv-c inhibits hiv replication and alter ...200314623022
the importance of the q motif in the atpase activity of a viral helicase.ns3 proteins of flaviviruses contain motifs which indicate that they possess protease and helicase activities. the helicases are members of the dexd/h box helicase superfamily and ns3 proteins from some flaviviruses have been shown to possess atpase and helicase activities in vitro. the q motif is a recently recognised cluster of nine amino acids common to most dexd/h box helicases which is proposed to regulate atp binding and hydrolysis. in addition a conserved residue occurs 17 amino acids ups ...200314623116
serologic diagnosis of west nile virus infection.the epidemic of west nile virus (wnv) in the usa in 2002 represents the largest outbreak of meningoencephalitis in the western hemisphere ever reported. besides natural transmission by mosquitoes, five new modes of wnv transmission to humans have been reported: blood transfusion, organ transplantation, transplacental transmission, breastfeeding and laboratory-acquired infection. the recognition of these new transmission routes has made the development of rapid and accurate serological diagnosis ...200314628901
epizootic activity of murray valley encephalitis and kunjin viruses in an aboriginal community in the southeast kimberley region of western australia: results of mosquito fauna and virus isolation studies.we undertook annual surveys of flavivirus activity in the community of billiluna in the southeast kimberley region of western australia between 1989 and 2001 [corrected]. culex annulirostris was the dominant mosquito species, particularly in years of above average rains and flooding. murray valley encephalitis (mve) virus was isolated in 8 of the 13 years of the study from seven mosquito species, but more than 90% of the isolates were from cx. annulirostris. the results suggest that mve virus is ...200314628944
antibody prophylaxis and therapy against west nile virus infection in wild-type and immunodeficient mice.west nile virus (wnv) is a mosquito-borne flavivirus that causes encephalitis in a subset of susceptible humans. current treatment for wnv infections is supportive, and no specific therapy or vaccine is available. in this study, we directly tested the prophylactic and therapeutic efficacy of polyclonal antibodies against wnv. passive administration of human gamma globulin or mouse serum prior to wnv infection protected congenic wild-type, b-cell-deficient ( micro mt), and t- and b-cell-deficient ...200314645550
protection of mice against experimental japanese encephalitis virus infections by neutralizing anti-glycoprotein e monoclonal antibodies.neutralizing monoclonal antibodies (mabs) to glycoprotein e (gpe) of japanese encephalitis (je) virus given intraperitoneally (i.p.) (0.1 ml of immune ascitic fluid (af) diluted 1:10 per mouse) to about 4-week-old swiss mice 1 day prior or 2 days after the virus challenge (100 ld50 of je virus administered intracerebrally (i.c.)) resulted in a decreased mortality along with an increased survival of the animals as demonstrated by the hai-positive virus-specific (hs) mabs. the protective effect pr ...200314658841
the extent of homologous recombination in members of the genus flavivirus.the family flaviviridae includes important human pathogens, such as dengue (den) virus, yellow fever (yf) virus and hepatitis c virus, many of which have emerged or re-emerged in recent years. until recently, flavivirus evolution was thought to proceed in a clonal manner, with diversity generated mainly through the accumulation of mutational changes. however, this assumption has now been shown to be invalid, with homologous recombination demonstrated in all three genera of the flaviviridae: sinc ...200312560576
a rapid and convenient variant of fusion-pcr to construct chimeric flaviviruses.so far, full-length cdnas of chimeric flaviviruses have been constructed by restriction-enzyme cleavage of the gene(s) to be exchanged or by fusion-pcr of two amplified pcr fragments. the construction of a chimeric flavivirus by a faster and more convenient variant of the standard fusion-pcr is reported. a modoc/yellow fever chimeric virus was engineered in which the structural prm and e genes of yellow fever virus 17d were replaced by the homologous genes of modoc virus. in two pcr steps, a fus ...200312565155
interferons, interferon inducers, and interferon-ribavirin in treatment of flavivirus-induced encephalitis in mice.we evaluated the prophylactic and therapeutic efficacy of interferon alpha-2b, pegylated interferon alpha-2b, poly(i. c), and ampligen against modoc virus encephalitis in an animal model for flavivirus infections. all compounds significantly delayed virus-induced morbidity (paralysis) and mortality (due to progressive encephalitis). viral load (as measured on day 7 postinfection) was significantly reduced by 80 to 100% in the serum, brain, and spleen in mice that had been treated with either int ...200312543691
spinal cord disease in west nile virus infection. 200312575663
impact of direct virus-induced neuronal dysfunction and immunological damage on the progression of flavivirus (modoc) encephalitis in a murine model.flavivirus encephalitis is believed to be the result of two main mechanisms: (i) direct damage to and dysfunction of neurons as a result of viral replication and (ii) destruction of the brain tissue by an inflammatory response. the differential impact of both mechanisms on the progression of flavivirus encephalitis has not been clearly determined. we have now studied the encephalitis caused by modoc virus (modv) infection in (i) severe combined immunodeficiency (scid) mice, (ii) immunocompetent ...200312587070
vaccinia virus recombinant expressing gene of tick-borne encephalitis virus non-structural ns1 protein elicits protective activity in mice.a vaccinia virus recombinant containing the non-structural tick-borne encephalitis virus (tbev) ns1 gene was developed. the recombinant expressed native dimeric form of the ns1 protein in infected cells and protected mice against lethal infection with tbev.200314687719
preface to the flaviviruses. 200314689688
preface to volume 60 the flaviviruses: pathogenesis and immunity. 200314689689
molecular determinants of virulence: the structural and functional basis for flavivirus attenuation. 200314689690
genetic resistance to flaviviruses.resistance to flavivirus-induced disease in mice was first discovered in the 1920s and was subsequently shown to be controlled by the resistant allele of a single dominant autosomal gene. while the majority of current laboratory mouse stains have a homozygous-susceptible phenotype, the resistant allele has been found to segregate in wild mouse populations in many different parts of the world. resistance is flavivirus specific and extends to both mosquito- and tick-borne flaviviruses. resistant a ...200314689691
immunobiology of mosquito-borne encephalitic flaviviruses. 200314689692
immune modulation by flaviviruses.flaviviruses cause pleomorphic disease with significant morbidity and mortality worldwide. interestingly, in contrast to most viruses, which subvert or avoid host immune systems, members of the neurotropic japanese encephalitis serocomplex cause functional changes associated with increased efficacy of the immune response. these viruses induce increased cell surface expression of immune recognition molecules, including class i and ii major histocompatibility complex (mhc) and various adhesion mol ...200314689693
dynamics of flavivirus infection in mosquitoes. 200314689695
dynamics of infection in tick vectors and at the tick-host interface.tick-borne flaviviruses are common, widespread, and successfully adapted to their mode of transmission. most tick vectors of flaviviruses are ixodid species. these ticks are characterized by a comparatively long life cycle, lasting several years, during which the infecting virus may be maintained from one developmental stage of the tick to the next. hence ticks act as highly efficient reservoirs of flaviviruses. many tick-borne flaviviruses are transmitted vertically, from adult to offspring, al ...200314689696
pathogenesis of flavivirus encephalitis. 200314689697
molecular biology of flaviviruses. 200314696326
flavivirus structure and membrane fusion. 200314696327
kunjin rna replication and applications of kunjin replicons.the kunjin virus (kunv) has provided a useful laboratory model for flavivirus rna replication. the synthesis of progeny rna(+) strands occurs via asymmetric and semiconservative replication on a template of recycling double-stranded rna (dsrna) or replicative form (rf). kinetics of viral rna synthesis indicated a cycle period of about 15 min during which, on average, a single nascent rna (+) strand displaces the pre-existing rna(+) strand in the replicative intermediate. data on the composition ...200314696328
antigenic structure of flavivirus proteins.the increased activity of dengue virus in the tropical regions of the world and the recent movement of west nile virus from the eastern to the western hemisphere emphasize the fact that vector-borne flaviviruses are medically important emerging infectious diseases. these facts warrant continued efforts to decode all facets of flavivirus immunology. this chapter reviews current understanding of the antigenic fine structure of flaviviral structural and nonstructural (ns) proteins and their involve ...200314696329
5'- and 3'-noncoding regions in flavivirus rna. 200314696330
manipulation of cell surface macromolecules by flaviviruses.cell surface macromolecules play a crucial role in the biology and pathobiology of flaviviruses, both as receptors for virus entry and as signaling molecules for cell-cell interactions in the processes of vascular permeability and inflammation. this review examines the cell tropism and pathogenesis of flaviviruses from the standpoint of cell surface molecules, which have been implicated as receptors in both virus-cell as well as cell-cell interactions. the emerging picture is one that encompasse ...200314696331
origins, evolution, and vector/host coadaptations within the genus flavivirus.although viruses in the genus flavivirus share complex antigenic interrelationships, they can be divided into four phylogenetic/ecological groups: two mosquito-borne groups, a tick-borne group, and nonvectored viruses. these divisions largely reflect the selective constraints imposed on the viruses by the vertebrate hosts, the invertebrate vectors, and the associated ecologies. phylogenetic trees based on the flavivirus genetic sequence show characteristic branching patterns that reflect these g ...200314696332
Displaying items 1501 - 1600 of 3318