molecular detection of west nile virus rna.west nile virus is a mosquito-borne flavivirus that is primarily maintained in nature in a mosquito-bird-mosquito transmission cycle. mammals, including humans and horses, are incidentally infected through biting by mosquitoes infected with west nile virus. since 1994, west nile virus outbreaks have occurred with a high incidence of severe disease in humans and horses. in the usa, west nile virus was first detected in 1999 in new york city and has since spread to 39 states in humans. the virus h ...200312779009
traditional and novel approaches to flavivirus vaccines.yellow fever, dengue, japanese encephalitis and tick-borne encephalitis viruses are the medically most important members of the flavivirus genus composed primarily of arboviruses. in this paper, we review the commercially available traditional flavivirus vaccines against yellow fever, japanese encephalitis, and tick-borne encephalitis, as well as modern approaches to flavivirus vaccines. formalin inactivation technology has been employed to produce killed vaccines. flaviviruses have been attenua ...200312782056
dendritic-cell-specific icam3-grabbing non-integrin is essential for the productive infection of human dendritic cells by mosquito-cell-derived dengue viruses.dengue virus (dv) is a mosquito-borne flavivirus that causes haemorrhagic fever in humans. dv primarily targets immature dendritic cells (dcs) after a bite by an infected mosquito vector. here, we analysed the interactions between dv and human-monocyte-derived dcs at the level of virus entry. we show that the dc-specific icam3-grabbing non-integrin (dc-sign) molecule, a cell-surface, mannose-specific, c-type lectin, binds mosquito-cell-derived dvs and allows viral replication. conclusive evidenc ...200312783086
poliomyelitis and flaviviruses. 200312783413
comparative population dynamics of mosquito-borne flaviviruses.among the members of the genus flavivirus are several important human pathogens, including the dengue (den) and japanese encephalitis (je) viruses. from the analysis of gene sequence data of samples of these virus populations it is possible to infer phylogenetic relationships, which in turn can yield important epidemiological information, including their demographic history in humans. in this study, we use a recently developed method, based on coalescent theory, to infer the population dynamics ...200312809802
the membrane proteins of flaviviruses form ion-permeable pores in the target membrane after fusion: identification of the pores and analysis of their possible role in virus infection.recently, we presented evidence that the e1 fusion protein of the alphavirus semliki forest virus forms ion-permeable pores in the target membrane after fusion. we proposed that the homologous fusion proteins of flaviviruses and hepatitis c virus form similar pores. to test this hypothesis for the e fusion protein of flaviviruses, the release of [(3)h]choline from liposomes by the flavivirus west nile (wn) virus was determined. [(3)h]choline was released at mildly acid ph. the ph threshold depen ...200312810864
antibody-dependent enhancement of murray valley encephalitis virus virulence in mice.enhancement of flavivirus infection in vitro in the presence of subneutralizing concentrations of homologous or heterologous antiserum has been well described. however, the importance of this phenomenon in the enhancement of flavivirus infection in vivo has not been established. in order to study antibody-mediated enhancement of flavivirus infection in vivo, we investigated the effect of passive immunization of mice with japanese encephalitis virus (je) antiserum on the outcome of infection with ...200312810865
distribution of three arbovirus antibodies among monkeys (macaca fascicularis) in the philippines.serum samples from 54 monkeys were collected from healthy individuals in a monkey farm in luzon island, philippines, in 1999, and examined by igm-capture elisa and indirect igg elisa for the presence of dengue (den), japanese encephalitis (je) and chikungunya (chik) viruses. the positive rates for igm elisa were 3.7, 35.2 and 14.8% against den, je and chik, respectively. higher positive rates were obtained when indirect igg elisa was used: 100% against flaviviruses (je or den) and 59.3% against ...200312823631
development of a quantitative real-time rt-pcr assay with internal control for the laboratory detection of tick borne encephalitis virus (tbev) rna.tick borne encephalitis virus (tbev), is a human flavivirus causing tick borne encephalitis (tbe), a viral infection of the central nervous system endemic in europe and asia.200312829035
kunjin virus replicon vectors for human immunodeficiency virus vaccine development.we have previously demonstrated the ability of the vaccine vectors based on replicon rna of the australian flavivirus kunjin (kun) to induce protective antiviral and anticancer cd8+ t-cell responses using murine polyepitope as a model immunogen (i. anraku, t. j. harvey, r. linedale, j. gardner, d. harrich, a. suhrbier, and a. a. khromykh, j. virol. 76:3791-3799, 2002). here we showed that immunization of balb/c mice with kun replicons encoding hiv-1 gag antigen resulted in induction of both gag- ...200312829819
molecular and functional analyses of kunjin virus infectious cdna clones demonstrate the essential roles for ns2a in virus assembly and for a nonconservative residue in ns3 in rna replication.a number of full-length cdna clones of kunjin virus (kun) were previously prepared; it was shown that two of them, pakun and flsdx, differed in specific infectivities of corresponding in vitro transcribed rnas by approximately 100,000-fold (a. a. khromykh et al., j. virol. 72:7270-7279, 1998). in this study, we analyzed a possible genetic determinant(s) of the observed differences in infectivity initially by sequencing the entire cdnas of both clones and comparing them with the published sequenc ...200312829820
involvement of lipids in different steps of the flavivirus fusion mechanism.flavivirus membrane fusion is triggered by acidic ph and mediated by the major envelope protein e. a structurally very similar fusion protein is found in alphaviruses, and these molecules are designated class ii viral fusion proteins. in contrast to that of flaviviruses, however, alphavirus fusion has been shown to be absolutely dependent on the presence of cholesterol and sphingomyelin in the target membrane, suggesting significant differences in the fusion protein-membrane interactions that le ...200312829825
clinical and laboratory findings on the first imported case of murray valley encephalitis in europe.murray valley encephalitis (mve) is an important mosquitoborne flavivirus infection endemic to australia and papua new guinea. we report the first imported case of mve in europe. a 23-year-old tourist developed severe encephalitis after having returned to germany from a long-term trip across the australian continent. the diagnosis was suspected on the basis of clinical findings and the patient's travel history and was confirmed by serological findings. the patient made a prolonged but complete r ...200312856229
managing occupational risks for hepatitis c transmission in the health care setting.hepatitis c virus (hcv) infection is a significant contemporary health problem in the united states and elsewhere. because it is primarily transmitted via blood, hepatitis c infection presents risks for both nosocomial transmission to patients and occupational spread to health care workers. recent insights into the pathogenesis, immunopathogenesis, natural history, and treatment of infection caused by this unique flavivirus provide a rationale for the use of new strategies for managing occupatio ...200312857782
dengue virus type 2 ns3 protease and ns2b-ns3 protease precursor induce apoptosis.apoptosis was detected in vero cell cultures expressing transfected dengue virus type 2 (denv-2) genes. approximately 17.5 and 51.5 % of cells expressing ns3 serine protease and ns2b-ns3(185) serine protease precursor protein [ns2b-ns3(185)(pro)] genes, respectively, were apoptotic. the percentage of apoptotic cells was significantly higher in cell cultures expressing ns2b-ns3(185)(pro). ns2b-ns3(185)(pro) was detected as ns2b-ns3(185)(pro)-egfp fusion protein in cytoplasmic vesicular structures ...200312867651
novel, potent phenethylamide inhibitors of the hepatitis c virus (hcv) ns3 protease: probing the role of p2 aryloxyprolines with hybrid structures.synthesis of hybrid hcv ns3 protease/ns4a inhibitors having the 4,4-difluoroaminobutyric acid (difluoroabu) phenethylamides as p1-p1' and quinolyloxyprolines as p2 fragments led to 7 (ic(50) 54 nm). molecular modelling suggests that this potent tripeptide inhibitor utilizes interactions in the s1', s1, s2, s3 and s4 sites of the protease.200312873506
tick-borne encephalitis: a retrospective study of clinical cases in bornholm, denmark.tick-borne encephalitis (tbe) is caused by a flavivirus, tick-borne encephalitis virus (tbev). for decades tbe has been known to cause disease in bornholm, a danish island. a retrospective study was performed to identify undiagnosed cases of tbe among patients hospitalized with signs and symptoms of meningitis or encephalitis in the 5 y period 1994-1999. this investigation revealed 5 new, and initially undiagnosed cases of tbe. in total, 14 cases of tbe were found in the 7 y period 1994-2000; 2 ...200312875531
incorporation of tick-borne encephalitis virus replicons into virus-like particles by a packaging cell line.rna replicons derived from flavivirus genomes show considerable potential as gene transfer and immunization vectors. a convenient and efficient encapsidation system is an important prerequisite for the practical application of such vectors. in this work, tick-borne encephalitis (tbe) virus replicons and an appropriate packaging cell line were constructed and characterized. a stable cho cell line constitutively expressing the two surface proteins prm/m and e (named cho-me cells) was generated and ...200312885909
brazilian flavivirus phylogeny based on this work, a comprehensive phylogenetic study based on 600 base pair nucleotide and on putative 200 amino acid sequences of ns5 was carried out in order to establish genetic relationships among 15 strains of 10 brazilian flaviviruses: bussuquara, cacipacore, dengue type 1, 2 and 4, iguape, ilheus, rocio, saint louis encephalitis (sle), and yellow fever. phylogenetic trees were created by neighbor-joining and maximum parsimony methods. these trees showed brazilian flaviviruses grouped into thr ...200312886419
alteration of clinical outcome and histopathology of yellow fever virus infection in a hamster model by previous infection with heterologous flaviviruses.using a recently described hamster model of severe yellow fever (yf), we examined the hypothesis that prior infection with heterologous flaviviruses protects against severe or fatal yf. hamsters were singly or sequentially infected with japanese encephalitis, st. louis encephalitis, west nile, and/or dengue-1 viruses, and then challenged with a virulent strain of yellow fever virus (yfv). in contrast to control (naive) hamsters, many of which appeared clinically ill or died after yfv infection, ...200312887029
acute undifferentiated fever caused by infection with japanese encephalitis determine the proportion of acute undifferentiated fevers without neurologic deficits related to infection with japanese encephalitis (je) virus, flavivirus serology (dengue and je) was performed in a cohort of 156 adults presenting to a hospital in chiangrai, thailand. recent flavivirus infection was diagnosed for any individual with an igm result > 40 units. a ratio of dengue virus igm to je virus igm < 0.91 defined a je virus infection. diagnostic criteria for japanese encephalitis were me ...200312887030
a trade-off in replication in mosquito versus mammalian systems conferred by a point mutation in the ns4b protein of dengue virus type acceptable live-attenuated dengue virus vaccine candidate should have low potential for transmission by mosquitoes. we have identified and characterized a mutation in dengue virus type 4 (den4) that decreases the ability of the virus to infect mosquitoes. a panel of 1248 mutagenized virus clones generated previously by chemical mutagenesis was screened for decreased replication in mosquito c6/36 cells but efficient replication in simian vero cells. one virus met these criteria and contained a ...200312890635
[specific determination of flaviviruses by molecular hybridization with synthetic deoxyoligonucleotide probes].molecular probes were designed for the purpose of specific determination of flavioviruses transmitted by the ticks of tick-borne encephalitis (tbe) and omsk hemorrhagic fever (ohv) as well as by mosquitoes of japanese encephalitis (je), north nile (nn), murrey valley encephalitis (mve), saint-lois encephalitis (sle), dengue 1-4 and of yellow fever (yf). the probes are synthetic deoxyoligonucleotides with the 18-20 long basis and complementary for the rna fragments defined by computer analysis. t ...200312894476
antigen-expressed recombinant salmonella typhimurium driven by an in vivo-activated promoter is capable of inducing cellular immune response in transgenic explore the approaches and mechanisms for reversing the immune tolerance in transgenic mouse, and the pathogenicity of hepatitis g virus (hgv), the promoter of phop-activated gene (p(pagc)) of salmonella typhimurium was used as a transcriptionally regulating element to construct an attenuated s. typhimurium expressing hgv ns3. the recombinant s. typhimurium was orally administered to hgv transgenic mice. as the results, hgv antigen in serum and liver as well as hgv mrna in liver were decrease ...200312897963
screening for t cell-eliciting proteins of japanese encephalitis virus in a healthy je-endemic human cohort using recombinant baculovirus-infected insect cell preparations.the analysis of cell-mediated immune responses in virus-exposed but healthy individuals may contribute to define the features of the t cell response associated with resistance. we report, for the first time, on adaptive t cell responses to 5 largest of the 10 proteins that together constitute 76% of the coding potential of the japanese encephalitis virus (jev) genome in a naturally exposed healthy je-immune human cohort. fixed and sonified whole cell preparations of insect cells individually exp ...200312898332
hepatitis c: a review.hepatitis c virus is an rna virus in the flavivirus family that was identified in 1989. since then, blood donor screening has reduced the incidence of acute infections; however, because this virus frequently leads to asymptomatic chronic infection, the prevalence of infection remains high. chronic infection leads to increased risks of cirrhosis and hepatocellular carcinoma, as well as extrahepatic manifestations. guidelines for widespread screening continue to evolve, and early diagnosis is like ...200312900622
discrimination of west nile virus and japanese encephalitis virus strains using rt-pcr rflp analysis.west nile (wn) virus is a mosquito-borne flavivirus that induces lethal encephalitis in humans and horses. since an outbreak of wn encephalitis in humans and horses occurred in new york city in late august 1999, the possibility exists that wn virus will invade regions that have close links with the united states, such as japan. we developed a genetic diagnostic method that discriminates between strains of wn virus and japanese encephalitis (je) virus. the method involves rt-pcr restriction fragm ...200312906104
chronic hepatitis associated with gb virus b persistence in a tamarin after intrahepatic inoculation of synthetic viral rna.progress in understanding the pathogenesis of hepatitis c virus (hcv) has been slowed by the absence of tractable small animal models. whereas gb virus b (gbv-b, an unclassified flavivirus) shares a phylogenetic relationship and several biologic attributes with hcv, including hepatotropism, it is not known to cause persistent infection, a hallmark of hcv. here, we document persistent gbv-b infection in one of two healthy tamarins (saguinus oedipus) inoculated intrahepatically with infectious syn ...200312907703
characterization of rna-dependent rna polymerase activity of csfv ns5b proteins expressed in escherichia coli.the full-length ns5b protein, and the truncated ns5b proteins of classical swine fever virus (csfv) resulted from deletion of 24, 36, 65 or 82, amino acid residues at the c terminal were expressed in escherichia coli cells and purified with a c-terminal hexahistidine tag. in addition to the full-length ns5b protein, those truncated ns5b proteins with deletion of 24, 36, or 65 amino acid residues were demonstrated to have rna-dependent rna polymerase (rdrp) activity, which was not found in the tr ...200312913359
mr findings in murray valley encephalitis.murray valley encephalitis (mve) is caused by a flavivirus related to west nile and st. louis encephalitis viruses. we report a case of mve resulting in quadriplegia and respiratory failure. mr imaging demonstrated thalamic hyperintensity on t2-weighted images, with similar involvement of the red nucleus, substantia nigra, and cervical cord. these findings preceded serologic diagnosis and are similar to those of japanese encephalitis. in the appropriate setting, thalamic t2 hyperintensity is sug ...200312917132
evidence for antigen production in muscles by dengue and japanese encephalitis dna vaccines and a relation to their immunogenicity in mice.this study demonstrated viral antigen production in muscle tissues following inoculation with dna vaccines and examined its relation to antibody induction in mice using the flavivirus system. to achieve detectable levels of antigen production, we used a needle-free jet injector and examined 10% homogenate of quadriceps muscle for viral antigens in a sandwich enzyme-linked immunosorbent assay. we compared dna vaccines against dengue type 1 (designated pcd1me), dengue type 2 (pcd2me) and japanese ...200312922102
induction of cross-protection against two wild-type taiwanese isolates of japanese encephalitis virus using beijing-1 strain dna vaccine.japanese encephalitis virus (jev), a mosquito-borne flavivirus, is an important human pathogen. mouse brain-derived, inactivated jev vaccines have contributed greatly to the reduction in numbers of je patients in several countries, including taiwan. however, mice immunized with the nakayama strain inactivated vaccine show lower protection against a lethal strain of beijing-1 jev than those immunized with the homologous vaccine. dna vaccine encoding the envelope (e) protein gene appears to provid ...200312922129
large genetic differentiation and low variation in vector competence for dengue and yellow fever viruses of aedes albopictus from brazil, the united states, and the cayman islands.we conducted a population genetic analysis of aedes albopictus collected from 20 sites in brazil, the united states (florida, georgia, and illinois), and the cayman islands. using isoenzyme analysis, we examined genetic diversity and patterns of gene flow. high genetic differentiation was found among brazilian samples, and between them and north american samples. regression analysis of genetic differentiation according to geographic distances indicated that ae. albopictus samples from florida we ...200312932107
growth characteristics of the veterinary vaccine candidate chimerivax-west nile (wn) virus in aedes and culex 1999 west nile (wn) virus was introduced to north america where this flavivirus has spread rapidly among wildlife (especially birds) transmitted by various species of mosquitoes (diptera: culicidae). increasing numbers of cases and deaths among humans, horses and other domestic animals require development of effective vaccines. 'chimerivax-west nile(vet)' is being developed for use as a veterinary vaccine to protect against wn infection. this chimeric virus contains the pre-membrane (prm) and ...200312941006
functional analysis of mosquito-borne flavivirus conserved sequence elements within 3' untranslated region of west nile virus by use of a reporting replicon that differentiates between viral translation and rna replication.we have developed a reporting replicon of west nile virus (wnv) that could be used to quantitatively distinguish viral translation and rna replication. a renilla luciferase (rluc) gene was fused in-frame with the open reading frame of a subgenomic replicon in the position where the viral structural region was deleted, resulting in rlucrep. transfection of bhk cells with rlucrep rna yielded two distinctive rluc signal peaks, one between 2 and 10 h and the other after 26 h posttransfection. by con ...200312941911
acute encephalitis, a poliomyelitis-like syndrome and neurological sequelae in a hamster model for flavivirus infections.infection of hamsters with the murine flavivirus modoc results in (meningo)encephalitis, which is, during the acute phase, frequently associated with flaccid paralysis, as also observed in patients with west nile virus encephalitis. twenty percent of the hamsters that recover from the acute encephalitis develop life-long neurological sequelae, reminiscent of those observed, for example, in survivors of japanese encephalitis. magnetic resonance imaging and histology revealed severe lesions predom ...200312946018
analysis of the complete genome of the tick-borne flavivirus omsk hemorrhagic fever virus.omsk hemorrhagic fever virus (ohf) is a tick-borne flavivirus endemic to western siberia. this virus is the only known tick-borne flavivirus to cause hemorrhagic disease in humans in the absence of encephalitis. ohf virus circulates within a small, defined niche in which other tick-borne complex flaviviruses are also present. the objectives of this study were to genetically classify ohf virus based on its complete genome and to identify genetic determinants that might be involved in tissue tropi ...200312951023
west nile virus in the united states: an update on an emerging infectious disease.west nile virus is a mosquito-borne flavivirus and human neuropathogen. since the virus was recognized in new york city in 1999, it has spread rapidly across the united states, with human disease documented in 39 states and the district of columbia. west nile virus can cause a broad range of clinical syndromes, including fever, meningitis, encephalitis, and a flaccid paralysis characteristic of a poliomyelitis-like syndrome. approximately one in 150 infections results in severe neurologic illnes ...200312952382
structural basis of a flavivirus recognized by its neutralizing antibody: solution structure of the domain iii of the japanese encephalitis virus envelope protein.the flavivirus envelope protein is the dominant antigen in eliciting neutralizing antibodies and plays an important role in inducing immunologic responses in the infected host. we have determined the solution structure of the major antigenic domain (domain iii) of the japanese encephalitis virus (jev) envelope protein. the jev domain iii forms a beta-barrel type structure composed of six antiparallel beta-strands resembling the immunoglobulin constant domain. we have also identified epitopes of ...200312952958
immunoassay targeting nonstructural protein 5 to differentiate west nile virus infection from dengue and st. louis encephalitis virus infections and from flavivirus vaccination.west nile virus (wnv) is an emerging flavivirus that has caused frequent epidemics since 1996. besides natural transmission by mosquitoes, wnv can also be transmitted through blood transfusion and organ transplantation, thus heightening the urgency of development of a specific and rapid serologic assay of wnv infection. the current immunoassays lack specificity because they are based on detection of antibodies against wnv structural proteins and immune responses to structural proteins among flav ...200312958248
diagnosis of tick-borne encephalitis by a mu-capture immunoglobulin m-enzyme immunoassay based on secreted recombinant antigen produced in insect cells.acute tick-borne encephalitis is diagnosed by detection of igm antibodies to tick-borne encephalitis virus (tbev) (genus flavivirus) in patient serum. tbev membrane (m) and envelope (e) proteins have previously been shown to form virus-like particles when expressed in mammalian cells. we expressed the prm/m and e proteins in insect cells with a recombinant baculovirus system and obtained antigenic protein secreted into the cell culture medium, as evidenced by detection by a panel of five monoclo ...200312958266
west nile virus: epidemiology, clinical presentation, diagnosis, and prevention.west nile virus was recognized in the united states for the first time in 1999, when it caused an epidemic of encephalitis and meningitis in new york city, ny. since then, the disease has been steadily moving westward, and human cases were recognized in 39 states and the district of columbia in 2002. the infection is caused by a flavivirus that is transmitted from birds to humans through the bite of culicine mosquitoes. most infections are mild, with symptoms primarily being fever, headache, and ...200312962168
characterization of resistance to non-obligate chain-terminating ribonucleoside analogs that inhibit hepatitis c virus replication in vitro.the urgent need for efficacious drugs to treat chronic hepatitis c virus (hcv) infection requires a concerted effort to develop inhibitors specific for virally encoded enzymes. we demonstrate that 2'-c-methyl ribonucleosides are efficient chain-terminating inhibitors of hcv genome replication. characterization of drug-resistant hcv replicons defined a single s282t mutation within the active site of the viral polymerase that conferred loss of sensitivity to structurally related compounds in both ...200312966103
proteasome activator pa28gamma-dependent nuclear retention and degradation of hepatitis c virus core protein.hepatitis c virus (hcv) core protein plays an important role in the formation of the viral nucleocapsid and a regulatory protein involved in hepatocarcinogenesis. in this study, we have identified proteasome activator pa28gamma (11s regulator gamma) as an hcv core binding protein by using yeast two-hybrid system. this interaction was demonstrated not only in cell culture but also in the livers of hcv core transgenic mice. these findings are extended to human hcv infection by the observation of t ...200312970408
significance in replication of the terminal nucleotides of the flavivirus genome.point mutations that resulted in a substitution of the conserved 3'-penultimate cytidine in genomic rna or the rna negative strand of the self-amplifying replicon of the flavivirus kunjin virus completely blocked in vivo replication. similarly, substitutions of the conserved 3'-terminal uridine in the rna negative or positive strand completely blocked replication or caused much-reduced replication, respectively. the same preference for cytidine in the 3'-terminal dinucleotide was noted in report ...200312970446
dengue virus m protein contains a proapoptotic sequence referred to as apoptom.the induction of apoptotic cell death is a prominent cytopathic effect of dengue (den) viruses. one of the key questions to be addressed is which viral components induce apoptosis in den virus-infected cells. this study investigated whether the small membrane (m) protein was involved in the induction of apoptosis by den virus. this was addressed by using a series of enhanced green fluorescent protein-fused den proteins. evidence is provided that intracellular production of the m ectodomains (res ...200313679613
association of japanese encephalitis virus ns3 protein with microtubules and tumour susceptibility gene 101 (tsg101) protein.previously reported findings by our group showed that non-structural protein 3 (ns3) of japanese encephalitis virus (jev) was localized mainly in the jev-induced convoluted membrane (cm), which has been proposed to originate from rough endoplasmic reticulum (rer), golgi apparatus or the trans-golgi network (tgn), and serves as a reservoir for viral proteins during virus assembly. earlier findings indicated that ns3 of kunjin virus interacts with microtubules. in addition, one of the golgi-associ ...200313679614
serological evidence of west nile virus, usutu virus and sindbis virus infection of birds in the uk.the introduction and rapid dispersal of the african flavivirus west nile virus (wnv) throughout north america, and the high fatality rate due to encephalitis in birds, horses, other wildlife species and humans, has attracted major attention worldwide. usutu virus, another flavivirus, came to prominence in 2001, when it was identified as the agent responsible for a drop in the bird population in austria; previously this encephalitic virus was found only in birds and mosquitoes in africa. sindbis ...200313679615
mutations which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus type 2/4 vaccine candidate in vero cells.mutations which increase the replication of dengue viruses in cell culture would greatly facilitate the manufacture of both a live attenuated or inactivated dengue virus vaccine. we have identified eight missense mutations in dengue virus type 4 (den4) that increase the plaque size and kinetics of replication of recombinant den4 virus in vero cells. den4 viruses bearing these vero cell adaptation mutations were also evaluated for the level of replication in the brains of mice. two of these eight ...200314505914
genetic systems of west nile virus and their potential applications.prevention and treatment of west nile virus (wnv) and other flavivirus infections have become a global public health priority. this fact is highlighted by the recent epidemic of wnv in the us. since the first outbreak of wnv in the us in 1999, the virus has caused over 4000 known human cases and at least 263 human deaths. the epidemic of wnv in the us in 2002 represents the largest meningoencephalitis outbreak in the western hemisphere, and the largest wnv outbreak ever reported. reverse genetic ...200314508880
sentinel chicken surveillance program in australia, july 2002 to june 2003.detection of flavivirus seroconversions in sentinel chicken flocks located throughout australia is used to provide an early warning of increased levels of murray valley encephalitis (mve) and kunjin (kun) virus activity in the region. during the 2002-2003 season low levels of flavivirus activity were detected in northern australia compared to previous years. mve and kun virus activity was detected in the kimberley and pilbara regions of western australia and the northern territory but not in nor ...200314510063
west nile virus-associated meningoencephalitis in two chronically immunosuppressed renal transplant recipients.west nile virus is a mosquito-borne, single-stranded rna virus of the flaviviridae family. approximately 1 in 150 patients who have serologic evidence of west nile virus infection develop encephalitis or meningitis. we report two chronically immunosuppressed renal transplant recipients with confirmed west nile virus meningoencephalitis acquired through community exposure. both patients presented with fever and neurological changes in the autumn of 2002. flavivirus-specific immunoglobulin m in an ...200314510707
molecularly engineered live-attenuated chimeric west nile/dengue virus vaccines protect rhesus monkeys from west nile virus.two molecularly engineered, live-attenuated west nile virus (wn) vaccine candidates were highly attenuated and protective in rhesus monkeys. the vaccine candidates are chimeric viruses (designated wn/den4) bearing the membrane precursor and envelope protein genes of wn on a backbone of dengue 4 virus (den4) with or without a deletion of 30 nucleotides (delta 30) in the 3' noncoding region of den4. viremia in wn/den4- infected monkeys was reduced 100-fold compared to that in wn- or den4-infected ...200314517072
rna-dependent rna polymerase activity of classical swine fever virus ns5b protein expressed in natural host cells.the ns5b gene, cloned from classical swine fever virus (csfv) genome, was expressed in porcine kidney cells pk-15, natural host of csfv. in purifying cytoplasmic extracts from these cells by means of different concentrations of salt, glycerol and detergent four fractions, namely crude supernatant (sc) and different purified supernatants (s1, s2 and s3) were obtained. using western blot analysis the ns5b protein was found in all these fractions, showing that it was soluble in both higher and lowe ...200314524473
imported dengue in french university hospitals: a 6-year survey.dengue fever (df) is a mosquito-transmitted acute disease caused by any of four dengue flavivirus serotypes (den-1, den-2, den-3, and den-4) which is becoming a major public health problem in intertropical areas.1 df is increasingly observed in febrile travelers returning from tropical areas,2 especially those returning from the caribbean islands and southeast asia, but it is rarely diagnosed in travelers returning from africa.3-8 diagnosis is often serologic, and in most cases is not confirmed; ...200314531982
characterisation of human tick-borne encephalitis virus from sweden.viruses of the tick-borne encephalitis (tbe) antigenic complex, within the family flaviviridae, cause a variety of diseases including uncomplicated febrile illness, meningo-encephalitis and haemorrhagic fever. different wildlife species act as reservoir hosts with ixodid tick species as vectors. tbe virus (tbev) causes 40-130 cases confirmed serologically in sweden each year. characteristics of tbev strains circulating in sweden have not been investigated previously and no viral sequence data ha ...200314556277
two distinct size classes of immature and mature subviral particles from tick-borne encephalitis virus.flaviviruses assemble in the endoplasmic reticulum by a mechanism that appears to be driven by lateral interactions between heterodimers of the envelope glycoproteins e and prm. immature intracellular virus particles are then transported through the secretory pathway and converted to their mature form by cleavage of the prm protein by the cellular protease furin. earlier studies showed that when the prm and e proteins of tick-borne encephalitis virus are expressed together in mammalian cells, th ...200314557621
dengue 2 pdk-53 virus as a chimeric carrier for tetravalent dengue vaccine development.attenuation markers of the candidate dengue 2 (d2) pdk-53 vaccine virus are encoded by mutations that reside outside of the structural gene region of the genome. we engineered nine dengue virus chimeras containing the premembrane (prm) and envelope (e) genes of wild-type d1 16007, d3 16562, or d4 1036 virus within the genetic backgrounds of wild-type d2 16681 virus and the two genetic variants (pdk53-e and pdk53-v) of the d2 pdk-53 vaccine virus. expression of the heterologous prm-e genes in the ...200314557629
zooprophylaxis or zoopotentiation: the outcome of introducing animals on vector transmission is highly dependent on the mosquito mortality while searching.zooprophylaxis, the diversion of disease carrying insects from humans to animals, may reduce transmission of diseases such as malaria. however, as the number of animals increases, improved availability of blood meals may increase mosquito survival, thereby countering the impact of diverting feeds.200314565850
cytochrome p450 2a6: a new hepatic autoantigen in patients with chronic hepatitis c virus infection.cytochromes p4502a6 (cyp2a6) and p4501a2 (cyp1a2) were described as hepatic autoantigens in the autoimmune polyglandular syndrome type-1 (aps-1). we evaluated the significance of anti-cyp2a6 and anti-cyp1a2 in several hepatic diseases in the absence of aps-1.200314568264
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
[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 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 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
inefficient signalase cleavage promotes efficient nucleocapsid incorporation into budding flavivirus membranes.the mechanism for efficient nucleocapsid (nc) uptake into flavivirus particles which form by budding through the membranes of the endoplasmic reticulum (er) was investigated by using murray valley encephalitis virus as a model. budding of flavivirus membranes is driven by the viral transmembrane proteins prm and e independently of nc interaction. we show that control of signalase cleavage of the multimembrane-spanning flavivirus polyprotein by the catalytic function of the viral protease is crit ...200414671099
an external loop region of domain iii of dengue virus type 2 envelope protein is involved in serotype-specific binding to mosquito but not mammalian cells.dengue virus (dv) is a flavivirus and infects mammalian cells through mosquito vectors. this study investigates the roles of domain iii of dv type 2 envelope protein (eiii) in dv binding to the host cell. recombinant eiii interferes with dv infection to bhk21 and c6/36 cells by blocking dengue virion adsorption to these cells. inhibition of eiii on bhk21 cells was broad with no serotype specificity; however, inhibition of eiii on c6/36 cells was relatively serotype specific. soluble heparin comp ...200414671119
tetracycline-inducible packaging cell line for production of flavivirus replicon particles.we have previously developed replicon vectors derived from the australian flavivirus kunjin that have a unique noncytopathic nature and have been shown to direct prolonged high-level expression of encoded heterologous genes in vitro and in vivo and to induce strong and long-lasting immune responses to encoded immunogens in mice. to facilitate further applications of these vectors in the form of virus-like particles (vlps), we have now generated a stable bhk packaging cell line, tetkuncprme, carr ...200414671135
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
high fidelity of yellow fever virus rna polymerase.three consecutive plaque purifications of four chimeric yellow fever virus-dengue virus (chimerivax-den) vaccine candidates against dengue virus types 1 to 4 were performed. the genome of each candidate was sequenced by the consensus approach after plaque purification and additional passages in cell culture. our data suggest that the nucleotide sequence error rate for sp6 rna polymerase used in the in vitro transcription step to initiate virus replication was as high as 1.34 x 10(-4) per copied ...200414694136
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
west nile virus: the indian scenario.west nile virus (wnv) is an important arthropod borne flavivirus; usually causes a mild infection called west nile fever (wnf) in human and horses. mosquitoes are the principal vectors of wnv. various culex species are found to act as vectors in different geographical regions. the virus is maintained in a bird-mosquito cycle in nature. in india, culex mosquitoes are tentatively incriminated as vectors of wnv. experimental studies have shown that culex tritaeniorhynchus, cx. vishnui, cx. bitaenio ...200314700342
flavivirus isolations from mosquitoes collected from western cape york peninsula, australia, 1999-2000.after the 1st appearance of japanese encephalitis virus (je) on mainland australia in 1998, a study was undertaken to investigate whether je had become established in enzootic transmission cycles on western cape york peninsula. adult mosquitoes were collected during the late wet season from kowanyama and pormpuraaw in april 1999, and pormpuraaw and barr's yard in april 2000. despite processing 269,270 mosquitoes for virus isolation, no isolates of je were obtained. however, other flaviviruses co ...200314710742
serodiagnosis of flaviviral infections and vaccinations in humans. 200314714429
molecular amplification assays for the detection of flaviviruses.over the past 10 years, a number of molecular amplification assays have been developed for the detection of flaviviruses. most of these assays utilize the reverse transcriptase-polymerase chain reaction (rt-pcr) as the amplification format with detection by either agarose gel electrophoresis and ethidium bromide staining or hybridization with molecular probes. recently, a modification of the standard rt-pcr using fluorescent-labeled oligonucleotide probes for detection (taqman) has been describe ...200314714430
tick-borne flaviviruses.tick-borne encephalitis (tbe), one of the most dangerous neuroinfections in europe and asia, is caused by tick-borne encephalitis virus (tbev) and currently involves approximately 11,000 human cases annually, mostly in russia. this chapter describes the main problems associated with the epidemiology, ecology, pathogenesis, and control of this disease. we have attempted to review the factors that influence the incidence and distribution of tbe, and to discuss possible reasons for the different cl ...200314714436
epidemiology of other arthropod-borne flaviviruses infecting humans. 200314714437
Displaying items 1601 - 1700 of 3318