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maintaining mosquito cell lines at high temperatures: effects on the replication of flaviviruses.the upper thermal limit for maintenance of eleven mosquito cell lines was studied. although most cell lines could be grown at 32 degrees c to 34 degrees c, anopheles stephensi cell line could be maintained at 37 degrees c. at higher temperatures initial growth rate was higher, but yield of cells after about a week of incubation was lower than at the standard temperature (28 degrees c). replication of several flaviviruses in aedes albopictus cell cultures adapted to 34.5 degrees c was faster, and ...19892563994
epitopic analysis of antigenic determinants on the surface of dengue-2 virions using monoclonal antibodies.the relative binding sites of dengue serotype-specific, dengue subcomplex-specific, dengue complex-specific, flavivirus subgroup-reactive, and flavivirus group-reactive monoclonal antibody preparations were identified by using competitive antibody binding assays. a dengue complex-specific epitope, capable of mediating infection enhancement, was identified on a 20,000 dalton protein found on intracellular virions. the other epitopes were assigned relative positions on the e glycoprotein by compet ...19852578750
clinical, clinicopathologic, and hematologic features of kyasanur forest disease.in 1957, a fatal disease occurred among monkeys in a forested area of shimoga district, karnataka state, india. concurrently, there was an outbreak of febrile, occasionally fatal illness among people living in the vicinity. the disease was caused by a new tick-borne flavivirus belonging to the russian spring-summer encephalitis complex of viruses. the early clinical description of the disease included severe cases with hemorrhagic manifestations, including intermittent epistaxis, hematemesis, me ...19892665018
[serologic study of arbovirus in 2 localities of the juventud island].a serologic study is made in two population groups in the isle of youth. a total 268 blood samples in blotting paper are subjected to the hemagglutination inhibition technique, using the eastern equine encephalomyelitis, western equine encephalomyelitis, saint louis encephalitis, and dengue 2 viruses; 16% positivity to flavivirus was found. a second serum sample was taken in people positive by the hemagglutination inhibition technique in order to carry out the techniques of complement fixation a ...19892561798
rearing temperature influences flavivirus vector competence of mosquitoes.culex annulirostris skuse mosquitoes (brisbane strain) were reared at 20 degrees c or 27 degrees c and the adult females were experimentally infected by feeding murray valley encephalitis virus (mve). they were then maintained (a) in the insectary at 20 degrees c, after rearing at either 20 degrees c or 27 degrees c; (b) at ambient outdoor temperatures, range 12.2-28.9 degrees c, mean 19.6 degrees c; or (c) at 27 degrees c after rearing at 27 degrees c. there was no significant difference in rat ...19892562419
characterization of japanese encephalitis virus envelope protein expressed by recombinant baculoviruses.recombinant baculoviruses containing the coding sequences of the viral structural proteins, i.e., the capsid (c) protein, the precursor to premembrane (prem) protein, and the envelope (e) protein, as well as a nonstructural protein, ns1, of japanese encephalitis virus (jev) were constructed. infection of spodoptera frugiperda cells with these recombinant viruses produced prem and e proteins. the e proteins synthesized by the recombinants were shown to be glycosylated and similar in size to the a ...19892688300
[a seroepidemiologic and virological study of the presence of arboviruses in moldavia in 1961-1982].in romania, st. drăgănescu et al., miszkolczy et al., based on clinical and epidemiological observations, affirmed the possible presence of "tick-borne encephalitis (tbe)". however, critical retrospective evaluation of certain others' papers published through 1958-1971 reveal some uncommon features. by way of example: a very high incidence of cf- and hi-antibodies in acute and chronic cns illnesses as well as in general population; replication in nucleus and maturation in mitochondria of a strai ...19892561524
[morphological study of omsk hemorrhagic fever (ohf) virus with the electron microscope].morphological characterization of ohf virus was studied by means of thin section electron microscopy in the brains of mice infected with omsk hemorrhagic fever virus. the crystals, microvesicles, vacuoles and as beehive structures were observed in the virus-infected cells. the possible relationship between the characteristic structures and virus morphogenesis is discussed. it is indicated that these characteristic structures may be important to morphological characterization of ohf virus.19892561476
cell-associated west nile flavivirus is covered with e+pre-m protein heterodimers which are destroyed and reorganized by proteolytic cleavage during virus release.flaviviruses are enveloped viruses which accumulate in cellular vacuoles prior to release. the membrane of cell-associated virus contains the proteins pre-m and e. during release of virus the pre-m protein is cleaved, and only its carboxy-terminal segment remains associated with the virus as m protein. studies of the association of membrane proteins of intracellular and extracellular particles of west nile virus show that in cell-associated virus the pre-m and e proteins are present as e+pre-m h ...19892724410
[arbovirus transmission cycles in madagascar].some arboviruses are highly pathogenic for men or animals, arboviruses epidemiological patterns in madagascar were determined by entomological, serological, and virological surveys. we listed potentials arboviruses vectors in madagascar. entomological results generated by us during five years, as well as prior to, are shown. we caught more than 150,000 hematophagous arthropods, belonging to 107 species at least. 3 of these species were new. 4183 inoculation pools were done. we studied serologica ...19892751393
[significance of igm titration by an immunoenzyme technic for the serodiagnosis and epidemiological surveillance of dengue in french polynesia].the usefulness of igm antibody capture enzyme-linked immunosorbent assay (elisa-igm) for the diagnosis of dengue was studied using several groups of sera. an attempt was made to detect igm against each dengue serotype. of 76 paired sera from patients with dengue type 4 infection, the diagnosis was confirmed by elisa-igm in 74: in 47 out of 49 primary dengue infections and in all 27 secondary dengue infections. it was possible to detect igm in 15 of the acute sera of primary infections and in 16 ...19892667066
characterization of the mesenteronal infection with western equine encephalomyelitis virus in an incompetent strain of culex tarsalis.interactions of western equine encephalomyelitis (wee) virus are compared with mesenterons of 2 genetically selected susceptible (ws) and refractory (wr) lines of culex tarsalis. both ws and wr females had similar susceptibility when parenterally inoculated with virus, thus it was initially thought that resistance in wr cx. tarsalis was associated with a mesenteronal infection barrier. present data on viral growth in mesenterons dissected from females fed on virus-soaked pledgets suggest that vi ...19892774065
detection of viral infection by immunofluorescence in formalin-fixed tissues, pretreated with trypsin.the presence of viral antigen in sections from formalin-fixed and paraffin-embedded human tissues was demonstrated by trypsin digestion followed by direct or indirect immunofluorescence. the specimens may be used for retrospective diagnosis. the immunofluorescence technique has to be adapted to the suspected virus infection on the basis of previous histopathologic study. variations of trypsin concentration time and temperature of incubation, expose different viral antigens and have to be previou ...19882687623
a case of dengue hemorrhagic fever in a japanese child.a 6-year-old japanese girl contracted a febrile illness with hemorrhagic manifestations when she traveled in indonesia. a remarkable decrease in the numbers of platelets and white blood cells was observed in her acute-phase blood specimens. her father, who accompanied her, showed dengue fever-like symptoms at almost the same time as her illness. it was determined by serological tests that they were infected with dengue virus type 1. moreover, she showed a secondary antibody response to the flavi ...19892779473
in vitro synthesis of japanese encephalitis virus (jev) rna: membrane and nuclear fractions of jev-infected cells possess high levels of virus-specific rna polymerase activity.japanese encephalitis virus (jev)-specific rnas (including 42s rna) were synthesized in subcellular fractions prepared from infected c6/36 cells. this in vitro rna synthesis essentially required mg2+ and four ribonucleotides, and it was enhanced by k+. the amounts of rna synthesized in vitro (in extracts from jev-infected cells) increased as a function of time after infection. the rna-synthetic activity in nuclear fractions was the highest among three kinds of subcellular fractions. our data sho ...19892816040
haemagglutination-inhibiting antibodies against arboviruses of the families togaviridae and bunyaviridae in birds caught in southern moravia, czechoslovakia.a total of 295 birds belonging to 19 species of 7 families of wild passeriformes were examined by haemagglutination-inhibition test. the birds were caught for an international research program "balt" at the time of autumn migration (august-september 1984). their blood sera were examined for antibodies against 6 arbovirus antigens of the genera alphavirus (sindbis-sin) and flavivirus (tick-borne encephalitis-tbe, west nile-wn) and family bunyaviridae (tahyna-tah, calovo-cvo and bhanja-bha). antib ...19872822552
analyses of the terminal sequences of west nile virus structural proteins and of the in vitro translation of these proteins allow the proposal of a complete scheme of the proteolytic cleavages involved in their synthesis.the proteolytic processes involved in the synthesis of the structural proteins of the west nile (wn) flavivirus were analyzed: the carboxy-terminal sequences of the structural proteins were determined and the proteins translated in vitro in the presence of membranes from a mrna coding for the structural polyprotein were analyzed. the results obtained indicate that the following proteolytic activities are involved in the synthesis and assembly of wn virus structural proteins: the growing peptide ...19892705302
enzyme immunoassay for the detection of dengue igg and igm antibodies using infected mosquito cells as antigen.the detection of immunoglobulin (ig)g and igm antibodies to dengue 1 virus was studied by a simple enzyme immunoassay, in which infected cultured cells infected with dengue virus were used as antigen (eia-icc). detection of anti-dengue 1 igg by eia-icc was correlated with haemagglutination assays. eia-icc anti-dengue 1 igm detection was less sensitive than igm capture enzyme-linked immunosorbent assay. igg and igm responses in dengue 1 infection were studied by eia-icc, using sera collected at d ...19892575811
replication strategy of kunjin virus: evidence for recycling role of replicative form rna as template in semiconservative and asymmetric replication.only three forms of kunjin virus-specified rna were isolated from cytoplasm early after the latent period (about 15 hr) viz., 44 s genomic-sized single-stranded rna, 20 s double-stranded "replicative form" (rf), and 20-28 s partially ribonuclease-resistant (about 70%) "replicative intermediate" (ri). the rf and ri were resolved by electrophoresis in aqueous-agarose gel only following licl fractionation. the ri did not enter urea-polyacrylamide gels. after denaturation of untreated or rnase-treat ...19852578239
william c. reeves and arbovirus research in australia.william c. reeves was invited to australia in 1952 to take part in field studies of murray valley encephalitis. the results of his work led to various hypotheses which directed arbovirus research in australia for a generation. that and the people he influenced in australia made him a major figure in the development of australian arbovirus research.19872825554
involvement of microtubules in kunjin virus replication. brief report.induction of microtubulin paracrystals (pc) by kunjin (kun) virus occurred after 15 hours post-infection and were often associated with convoluted membranes (cm) and virus particles. vinblastine sulphate which disrupts microtubulin, had an inhibitory effect on the virus production when added during the viral latent period. when infected samples were extracted with triton x-100 and analysed by sds-page, four viral proteins were observed.19872825618
[mac-elisa for the detection of igm antibodies to dengue type i virus (rapid diagnosis of dengue type i virus infection)].the commercial rapid diagnostic reagents for dengue virus infection is still not available at present. an abc mac-elisa (avidin biotin complex igm antibody capture enzyme linked immunosorbent assay) for the detection of dengue type i virus infection has been described. igg purified from high titer (hi = 2560) human anti-flavivirus serum is labelled with biotin for the rapid diagnosis of dengue type i virus infection. 389 serum specimens of suspected dengue fever patients including 226 hi(+) pair ...19892700156
nucleotide and complete amino acid sequences of kunjin virus: definitive gene order and characteristics of the virus-specified proteins.a kunjin (kun) virus cdna sequence of 10664 nucleotides was obtained and it encoded a single open reading frame for 3433 amino acids. partial n-terminal amino acid analyses of kun virus-specified proteins identified the polyprotein cleavage sites and the definitive gene order. the gene order relative to that proposed for yellow fever (yf) virus is as follows: kun 5'-c.gp20.e.gp44.p19.p10.p71.(?).p21.p98-3' yf 5'-c.prm.e.ns1.ns2a.ns2b.ns3.ns4a.ns4b. ns5-3'. the order of putative signal sequences ...19882826659
recent advances in the molecular biology of flaviviruses. 19862824939
nucleotide sequence of dengue 2 rna and comparison of the encoded proteins with those of other flaviviruses.we have determined the complete sequence of the rna of dengue 2 virus (s1 candidate vaccine strain derived from the pr-159 isolate) with the exception of about 15 nucleotides at the 5' end. the genome organization is the same as that deduced earlier for other flaviviruses and the amino acid sequences of the encoded dengue 2 proteins show striking homology to those of other flaviviruses. the overall amino acid sequence similarity between dengue 2 and yellow fever virus is 44.7%, whereas that betw ...19882827375
evidence that the mature form of the flavivirus nonstructural protein ns1 is a dimer.evidence is presented which indicates that the dengue-2 virus nonstructural protein ns1 (soluble complement fixing antigen) exists in infected bhk and mosquito cell cultures as part of a stable oligomer. identification of the dissociation products of the isolated oligomer and comparison of the number of n-linked glycans in native and denatured ns1 is consistent with the idea that the high-molecular-weight form of ns1 is a homodimer. by analyzing lysates of bhk cells infected with st. louis encep ...19882827377
persistence of encephalitogenic arboviruses in brain cell culture. brief report.virus recovery from brain cultures of mice infected with either semliki forest and/or langat depended on the time interval between inoculation of either virus. mixed infections may alter the course of a disease.19872827614
dengue virus, a flavivirus, propagates in human bone marrow progenitors and hematopoietic cell lines.dengue and other arbovirus diseases are frequently associated with bone marrow failure. we show that dengue type 4 (den4) propagates in colonies derived from immature human bone marrow progenitors. den4 was propagated in bfu-e-derived colonies and replication was dependent on erythropoietin. den4 was not cytotoxic. in inoculated cultures, diffuse bursts with many clusters contained large amounts of den4 rna. in contrast to dengue infection of macrophages, virus propagation in semisolid culture w ...19892765663
differential phosphorylation of the nucleoprotein of influenza a viruses.an analysis of the nucleoprotein (np) of 29 different influenza a viruses by phosphopeptide fingerprinting revealed three prototype patterns. the first, which was a complex pattern consisting of six to seven phosphopeptides, another which was relatively simple consisted of two or three phosphopeptides, and a third one which was complex but was missing the main phosphopeptide shared by the two other patterns. phosphoserine was the only labelled phosphamino acid detected. a tentative deduction of ...19892778438
biochemical and biophysical characteristics of rio bravo virus (flaviviridae).rio bravo (rb) virus has been assigned to the family flaviviridae on the basis of its antigenic relatedness to other members of this family. rb virus, unlike most members of the flaviviridae, is believed not to have an arthropod vector. we examined biochemical and biophysical characteristics of rb virus to determine whether it should be assigned to the flaviviridae and to compare it with arthropod-borne flaviviruses. purified rb virus banded at a density of 1.18 g/ml in sucrose and had a sedimen ...19882828514
conserved elements in the 3' untranslated region of flavivirus rnas and potential cyclization sequences.we have isolated a cdna clone after reverse transcription of the genomic rna of asibi yellow fever virus whose structure suggests it was formed by self-priming from a 3'-terminal hairpin of 87 nucleotides in the genomic rna. we have also isolated a clone from cdna made to murray valley encephalitis virus rna that also appears to have arisen by self-priming from a 3'-terminal structure very similar or identical to that of yellow fever. in addition, 3'-terminal sequencing of the s1 strain of dengu ...19872828633
gene mapping and positive identification of the non-structural proteins ns2a, ns2b, ns3, ns4b and ns5 of the flavivirus kunjin and their cleavage sites.partial n-terminal amino acid analyses of five radiolabelled non-structural (ns) proteins specified by kunjin (kun) virus provided positive identification of ns3, ns5 and three previously hypothetical ns proteins of flaviviruses, ns2a, ns2b and ns4b. their correct gene order was obtained from their deduced amino acid sequences. thus the gene order for kun virus relative to that proposed for yellow fever (yf) virus was as follows: kun 5'...gp44.p19.p10.p71.(?).p21.p98-3', yf 5'...ns1.ns2a.ns2b.ns ...19882826667
flavivirus-specific murine l3t4+ t cell clones: induction, characterization and cross-reactivity.murine t cell clones specific for the kunjin (kun), west nile (wn) and murray valley encephalitis (mve) flaviviruses were generated in vitro following priming in vivo. clones were isolated by limiting dilution and maintained in culture with antigen stimulation and interleukin-2(il-2). the cells were characterized as having the thy 1+, l3t4+ and lyt 2- phenotype by immunofluorescence. all clones proliferated strongly and secreted high levels of il-2 and il-3 in response to homologous antigen. bot ...19872822843
the effect of gold sodium thiomalate in adult swiss/a2g mice infected with togaviruses and flaviviruses.treatment of adult mice with gold sodium thiomalate made the normally non-lethal semliki forest virus and sindbis virus infections lethal and increased the virulence of langat and west nile viruses. these changes were associated with an enhanced virus invasion of the brain. depression of the humoral antibody response was not observed.19872822844
california serogroup and powassan virus infection of cats.one hundred and seventy five sera from cats in ontario, canada, were tested for hemagglutination inhibition (hi) antibodies to three arboviruses; namely, powassan (pow) of the flavivirus serogroup, and snowshoe hare (ssh) and jamestown canyon (jc) viruses of the california (cal) serogroup. all sera were negative for antibodies to pow virus. twelve cats possessed cal serogroup antibodies including 3 with antibodies to ssh alone, 6 with antibodies to jc alone, and 3 with antibodies to both ssh and ...19872825952
sequence and secondary structure analysis of the 5'-terminal region of flavivirus genome rna.the 5'-terminal noncoding region sequences were determined for the genome rnas of seven strains of st. louis encephalitis virus (slev) and one strain of west nile virus (wnv) using a single synthetic cdna primer complementary to the 5'-terminus of the coding region of a strain of wnv rna. the 5'-terminal sequences obtained for the slev and wnv rnas were compared with published sequences for yellow fever virus (yfv), murray valley encephalitis virus (mvev), and dengue virus. while only short regi ...19882829420
a rapid dot immunoassay for the detection of serum antibodies to eastern equine encephalomyelitis and st. louis encephalitis viruses in sentinel chickens.a dot enzyme-linked immunosorbent assay utilizing a novel membrane, polyvinylidene difluoride, is described. this assay was developed for the rapid detection of serum antibodies to eastern equine encephalomyelitis virus and st. louis encephalitis virus in sentinel chickens. antigens were spot-filtered through the membrane. membranes were dipped into small vials of sera. antigen-antibody complexes were detected with enzyme-conjugated antiglobulin which, when exposed to substrate, produced a color ...19882829636
heterologous flavivirus infection-enhancing antibodies in sera of nigerians.human sera collected from nigerians were examined for plaque reduction neutralizing and infection-enhancing antibodies against dengue 2, yellow fever, and west nile viruses. neutralization tests showed that 17 of 19 sera contained flavivirus neutralizing antibody; 11 were positive to all 3 viruses, 5 to dengue and yellow fever, and 1 to dengue virus only. two sera had no detectable neutralizing antibody to any of the flaviviruses. enhancement assays showed that 17 flavivirus neutralizing antibod ...19882829637
the status of dengue fever virus in south africa--serological studies and diagnosis of a case of dengue fever.to assess the possibility of a dengue epidemic occurring in south africa 3 groups of survey sera and 2 groups of patients' sera, from a dengue high risk area of south africa, were tested for antibodies to several flaviviruses. 3.8% (75/1951) of the survey sera and 9.2% (26/282) of the patients' sera had haemagglutination inhibition antibodies to one or more of the flaviviruses tested. one of 1951 survey sera had a spectrum of complement fixation antibody consistent with a primary dengue infectio ...19872832982
further observations on the mechanism of vertical transmission of flaviviruses by aedes mosquitoes.as previously observed for dengue viruses, vertical (i.e., transgenerational) transmission of japanese and st. louis encephalitis viruses by aedes albopictus takes place when the fully formed egg, enclosed in the chorion, is oviposited. the demonstration of such a mechanism for three flaviviruses suggests that vertical transmission of all mosquito-borne flaviviruses may occur in the same manner.19882840833
genetic variation of murray valley encephalitis virus.the genomes of 21 isolates of murray valley encephalitis virus (mve) from australia and papua new guinea were characterized and compared using rnase t1 oligonucleotide fingerprinting. most australian isolates grouped in clusters that were linked with a similarity coefficient of greater than 75%, indicating substantial homogeneity. two isolates grouped as a cluster that linked with other isolates at a level of 67%. these two isolates, one from the north and one from the south-east of australia we ...19882841405
detection of virus-specific antigen in the nuclei or nucleoli of cells infected with zika or langat virus.two monoclonal antibodies (mabs) with molecular specificities for either the viral envelope glycoprotein (mab 541) or the non-structural ns1 glycoprotein (mab 109) were derived using west nile and yellow fever (yf) viruses respectively. their antigenic reactivity with a large number of flaviviruses was tested by indirect immunofluorescence microscopy. both produced cytoplasmic fluorescent staining patterns with the homologous virus against which they were raised. additionally, mab 541 reacted wi ...19882841406
antigenic analysis of west nile virus strains using monoclonal antibodies.seventeen monoclonal antibodies (mabs) were prepared against the flavivirus west nile strain h442. while the majority of these were specific for the major envelope protein, mabs directed against the ns1 and ns4a nonstructural proteins were also identified. the mabs were tested by indirect immunofluorescence against 16 southern african west nile (wn) isolates, representative strains from the two main wn antigenic groups and several viruses from other flavivirus complexes. the mab reactivities ran ...19882833205
[flavivirus: serological survey in horses from the tandil area].sera from 282 equines from tandil country and surroundings were investigated searching for hemagglutination inhibition (hi), complement fixation (cf), and neutralizing (nt) antibodies against three flavivirus:ilheus, st. louis encephalitis, and yellow fever from the togaviridae family. sera were collected between 3-20-79 and 11-25-80 from 10 different places in tandil and ayacucho countries. animals ranged from 45 days to 27 years old. forty nine of them reacted with one or more flavivirus by hi ...19852829272
translation mapping with the flavivirus kunjin: gene order and anomalies in translation of ns5.kunjin (kun) virus-infected cells were synchronized in translation by reversal of hypertonic inhibition; cells were then pulse-labelled with [35s]methionine. electrophoretic analyses defined the sequence of incorporation of label into all the known kun gene products shown previously to be unique and unrelated. gp44 or ns1 was inadequately labelled for analysis and was assumed to be translated sequentially after e in the polyprotein sequence. the relationship of the kun gene order obtained by tra ...19882837017
cns pathogenesis following a dual viral infection with semliki forest (alphavirus) and langat (flavivirus).mice inoculated intraperitoneally with the alphavirus semliki forest were protected against a subsequent challenge with the flavivirus langat. the protection was seen as a reduction in the langat virus titres, mortality index and percentage deaths. the severity of the brain pathology was greater in the simultaneously infected mice, or when the time interval between administration of the viruses was 7 days, compared to that seen following a single infection of either semliki forest or langat viru ...19882837265
establishment and characterization of st louis encephalitis virus persistent infections in aedes and culex mosquito cell lines.persistent infections with st louis encephalitis (sle) virus were established in three mosquito cell lines (aedes albopictus, a. dorsalis and culex tarsalis) and were maintained for over 2 years. all three persistently infected cell cultures shared two features: (i) no overt cytopathic effect and (ii) a relatively high proportion of cells infected (41 to 85%). the aedes persistently infected cultures were resistant to superinfection with the homologous virus but not heterologous viruses. two sig ...19882842432
[chemoprophylaxis and chemotherapy of arbo- and arenavirus infections]. 19882845668
[monoclonal antibodies to flavivirus antigens induced by a vaccinal strain of yellow fever].monoclonal antibodies (mabs) yel-2 induced by the vaccine fns dakar yellow fever (yf) virus were characterized for their capacity to enter into serological reactions and to react with heterologous flaviviruses. yel-2 mabs belong to the igg2a class of immunoglobulins, possess the antihemagglutination properties, are active in indirect if test but do not activate complement and have no neutralizing properties. the inability to enter into cft in the presence of antihemagglutinating properties sugge ...19882848367
[modification during experimental flavivirus infection of the formation of a b-cell immunologic memory to heterologous antigen]. 19882848369
comparisons of the pestivirus bovine viral diarrhoea virus with members of the flaviviridae.the molecular features of bovine viral diarrhoea virus (bvdv), a member of the pestivirus genus currently classified in the togaviridae, were examined for characteristics resembling those of the flaviviridae family. like flaviviruses, bvdv possesses a single-stranded rna genome (approx. 4.3 x 10(6) mr) deficient in a 3' poly(a) tract. this rna has a single open reading frame spanning the length of the genome in the viral rna sense (positive polarity), implying an expression strategy involving th ...19882844971
phenotypes of st louis encephalitis virus mutants produced in persistently infected mosquito cell cultures.viral mutants that appeared during long-term persistent infections of mosquito cell cultures (aedes albopictus, a. dorsalis and culex tarsalis) with st louis encephalitis virus were characterized. evidence was obtained for the presence of temperature-sensitive mutants in the a. dorsalis and c. tarsalis persistently infected cultures, and small plaque mutants were predominant in all cultures except one of two cell cultures of c. tarsalis. virus from persistently infected a. albopictus cell cultur ...19882842433
murray valley encephalitis virus field strains from australia and papua new guinea: studies on the sequence of the major envelope protein gene and virulence for mice.we have compared the nucleotide sequence of the gene encoding the major envelope (e) protein of a number of murray valley encephalitis virus (mve) isolates from australia and papua new guinea (png). the isolates, from widely separated geographic regions, were from four fatal human cases, a heron, and six mosquito pools and covered a period of 25 years. the sequences of the australian strains were notable for their similarity, showing not more than 1.7% nucleotide sequence divergence in pairwise ...19882838962
protection against japanese encephalitis by inactivated vaccines.encephalitis caused by japanese encephalitis virus occurs in annual epidemics throughout asia, making it the principal cause of epidemic viral encephalitis in the world. no currently available vaccine has demonstrated efficacy in preventing this disease in a controlled trial. we performed a placebo-controlled, blinded, randomized trial in a northern thai province, with two doses of monovalent (nakayama strain) or bivalent (nakayama plus beijing strains) inactivated, purified japanese encephaliti ...19882842677
occurrence of tick-borne encephalitis (tbe) virus in berlin (west).the main vector of central european tick-borne encephalitis (tbe), the hard tick ixodes ricinus, is very common in forests of berlin (west) all of which are frequently visited nearby recreation areas. while the presence of the causative agent, a flavivirus, has been demonstrated in all districts of the german democratic republic (gdr) there has been no corresponding investigation concerning berlin (west). in the present study, 4593 unengorged i. ricinus nymphs and adults were collected by the fl ...19882850694
1987 yellow fever epidemics in oyo state, nigeria: a survey for yellow fever virus haemagglutination inhibiting antibody in residents of two communities before and after the epidemics.a survey for yellow fever haemagglutination inhibiting antibody was carried out before and after the 1987 yellow fever epidemics in nigeria in two localities in oyo state, namely: ibadan and ogbomosho. a total of 129 sera were collected from the two localities before the epidemic. the overall prevalence of yellow fever hi antibody was 37%. a breakdown of positive sera showed that 30/100 and 18/29 sera tested in ibadan and ogbomosho respectively were positive. there was a higher prevalence of hi ...19882851207
flavivirus vaccines.diseases caused by flavivirus infection have been a scourge of mankind for over three centuries; with yellow fever, dengue fever and russian spring-summer encephalitis causing epidemics resulting in thousands of fatalities. due to the development of a safe and efficacious live-attenuated vaccine against yellow fever, this disease is no longer such a threat in countries where adequate vaccination is practised. a similarly safe and efficacious inactivated vaccine against central-european tick-born ...19882854336
susceptibility of mammalian cell cultures to infection with arbo-togaviruses.six alphaviruses and four flaviviruses were inoculated intracerebrally into 1 to 3 days old suckling mice. all mice developed cns diseases and died 2-5 days post-infection. it appeared that alphaviruses were more virulent than flaviviruses since they brought death to the injected mice earlier than the flaviviruses. the susceptibilities of nine different culture cells to those viruses were also investigated using plaque assay. bhk-21 cells produced clearer plaques and were more sensitive than oth ...19872835211
clinical and pathological responses of west african dwarf goats (fouta djallon) infected with nigerian strain of wesselsbron virus. 19882855376
molecular biology of the flaviviruses.an overview of the molecular biology of the flaviviruses is presented. the members of this virus family are enveloped positive-strand rna viruses capable of causing a number of important human diseases.19872856425
antigen-specific transfer factor from mice immunized with an attenuated flavivirus: augmentation of inducing activity in semipurified splenocytic dialyzates.three large batches were prepared of lyzed splenocytic leukocyte dialyzate from spf outbred mice, immunized with a live attenuated virus from the tick-borne encephalitis (tbe) complex. total mass of freeze-dried dialyzates was 1.73 g. one mg of respective batches contained 2 x 10(5), 2 x 10(4) and 2 x 10(3) units of the transfer factor, specific for the flavivirus group-antigen, as estimated according to the capacity to induce specifically cytotoxic t-cells in the recipient c3h mice. the amount ...19852859759
virus-induced decrease in the activity of serum blocking factor(s): a mechanism of activation of the autoreactive t effectors in graft versus host reaction and of controlling t suppressors.it has been shown that serum blocking factor(s) (sbf) previously detected in normal mice bind(s) to receptors on the surface membranes of virus-induced autoreactive t lymphocytes (artl) and to that of artl activity inhibiting t suppressors (tsar). the interaction of sbf with the receptors is reversible, h-2 restricted and associated with the inhibition of functional activity of the tested t lymphocyte populations. in mice during acute tick-borne encephalitis (tbe), in the course of inapparent in ...19852859760
comparative susceptibility of five species of toxorhynchites mosquitoes to parenteral infection with dengue and other flaviviruses.five species of colonized toxorhynchites mosquitoes were compared for relative susceptibility to parenteral infection with the four dengue serotypes and st. louis and japanese encephalitis viruses. tx. amboinensis, tx. brevipalpis, tx. rutilus, and tx. splendens were equally susceptible to infection with the dengue viruses, while tx. theobaldi was relatively resistant to infection with those viruses. all five mosquito species were equally susceptible to infection with the encephalitis viruses. t ...19852862802
localization of arboviral antigen in brain tissues from patients with encephalitis.brain tissues from 38 patients with a clinical suspicion of encephalitis or encephalopathy were examined by two immunoenzymatic techniques for the detection of arboviral antigen. group b arboviral antigen was identified in 23 of these tissues. this simple method could be used for the diagnosis of the causal agent of encephalitis.19882852405
experimental study of the reproduction of karshi virus (togaviridae, flavivirus) in some species of mosquitoes and ticks.the strain kaz-816 of karshi virus was isolated in 1976 from h. asiaticum ticks collected in the north of central asia (alma-ata region of the kazakh soviet socialist republic). both ticks and mosquitoes can be vectors of karshi virus as proved experimentally by reproduction of the virus in hyalomma asiaticum and dermacentor daghestanicus ticks and culex pipiens molestus, anopheles atroparvus an aedes aegypti mosquitoes as well as by transmission to newborn mice by the bite of infected mosquitoe ...19852864824
antigen capture elisa for the identification of dengue viruses.we developed a simple antigen capture enzyme immunosorbent assay (agc-elisa) for identifying dengue (den) virus. the method employed serotype-specific monoclonal antibodies as capture antibodies and an enzyme conjugate of a flavivirus-reactive monoclonal antibody as a detecting antibody. most den virus strains, representing all 4 serotypes isolated from various parts of the tropics, were identical either visually of spectrophotometrically when infected cell culture fluids were used as sources of ...19852867103
blood value changes in flavivirus-inoculated macaca fascicularis monkeys.blood values were analysed in eighteen cynomolgus monkeys on pre-and post-neurovirulence testing of dengue-2 and yellow fever vaccine viruses, dengue-2 parental and japanese encephalitis viruses. certain changes between blood chemistry, hematology and serology were observed and briefly discussed.19862874612
changes of natural killer cell activity in different mouse lines by acute and asymptomatic flavivirus infections.effect of certain flaviviruses on the activity of mouse natural killer (nk) cells was investigated using the classical mouse splenocyte system and yac-1 cells for demonstration of nk cell cytotoxicity. infection of mice with langat and west nile (wn) viruses was accompanied by temporary activation of nk cells. in mice infected with tick-borne encephalitis (tbe) virus the stimulation phase of nk cell cytotoxicity on days 2-4 post-infection (p.i.) was followed by suppression of their activity. as ...19862876611
[arbovirus-vector-vertebrate cycles in madagascan forests]. 19862879516
stability of st. louis encephalitis viral antigen detected by enzyme immunoassay in infected mosquitoes.the use of enzyme immunoassay to detect st. louis encephalitis (sle) viral antigen in vector mosquitoes enhances the effectiveness of surveillance because infected mosquitoes can be identified more rapidly than with conventional virus isolation systems and because it is a simple and accessible procedure. infectivity among mosquitoes experimentally infected with sle virus was lost within 24 h after the mosquitoes were stored at 27 degrees c and 80% relative humidity; however, viral antigen remain ...19882852675
interferon-independent increases in class i major histocompatibility complex antigen expression follow flavivirus infection.infection of tertiary-passaged mouse embryo fibroblasts by four flaviviruses, west nile (wnv), kunjin, murray valley encephalitis and japanese b encephalitis, resulted in a six- to 10-fold increase in the expression of individual h-2k and h-2d class i major histocompatibility complex (mhc) antigens 16 to 48 h after infection. the mechanism(s) by which flaviviruses increased antigen expression has not been fully elucidated, but appears to be mediated partly independently of interferon-beta (ifn-b ...19882844965
identification of flaviviruses by the single-radial-haemolysis test. 19862883117
a study of viral and rickettsial exposure and causes of fever in juba, southern sudan.patients presenting at the juba teaching hospital, either with fever of undetermined origin or with a clinical cause of fever, gave evidence of exposure to a wide range of viral and rickettsial agents. serological tests showed high antibody levels to flaviviruses (56.9%) and alphaviruses (29.2%), with lesser levels of bunyamweraviruses (3.8%), rift valley fever (2.3%), and sandfly fever (0.75%). flavivirus exposure was significantly associated with clinical evidence of liver disease; repeated ex ...19882855284
virus isolations from mosquitoes collected during the 1982 japanese encephalitis epidemic in northern thailand.from 16 june to 15 august, 1982 cdc light traps were used to collect mosquitoes in the province of kamphaengphet, n. thailand. 353,042 mosquitoes comprising 59 species were collected and identified, and 345,173 were placed in pools for attempted virus isolation by inoculation of c6/36 aedes albopictus mosquito cell cultures. viruses were isolated from 63 mosquito pools. these comprised 56 flaviviruses, identified as 35 isolates of japanese encephalitis (je) virus strains, 18 strains of tembusu ( ...19862885948
overwintering mechanisms of mosquito-borne arboviruses in temperate climates.it can be concluded from the data cited that transovarial transmission is a plausible explanation for the overwintering of mosquito-borne bunyaviruses of the california serogroup. vertical transmission of mosquito-borne flaviviruses could explain the overwintering of this group of viruses, but this is far from having been established. at present, the mechanism by which mosquito-borne alphaviruses pass the winter is obscure.19872891312
genetic differentiation of murray valley encephalitis virus in australia and papua new guinea.the genetic relatedness of ten murray valley encephalitis virus (mve) isolates from australia has been examined by comparing haeiii and taqi restriction digest profiles of cdna to virion rna. the isolates were from the murray valley region of south-eastern australia and from the ord river region of western australia and spanned a period of 23 years (1951-1974). the isolates generated closely similar restriction digest profiles. the extent of similarity suggested that the level of nucleotide sequ ...19862884985
the importance of autumn rainfall and sentinel flock location to understanding the epidemiology of st. louis encephalitis virus in indian river county, florida.culex nigripalpus adults were collected from sentinel chickens at 4 sites in indian river co. (irc), florida. chickens located in well drained, open habitats attracted fewer cx. nigripalpus than did those located in a moist, forested area, but the number of mosquitoes collected in the open habitats increased significantly with heavy autumn rainfall. all st. louis encephalitis virus (sle) seroconversions (11/674) during a 7-year period were from chickens located in open, well drained habitats. a ...19852852706
arbovirus investigations in argentina, 1977-1980. iv. serologic surveys and sentinel equine program.serologic surveys of wild and domestic birds, wild mammals, and horses were conducted during arbovirus field studies in argentina from 1977 through 1980, a non-epizootic interval. the prevalence of neutralizing antibodies to eastern equine encephalitis (eee) was consistently higher than to western equine encephalitis (wee) virus in all species and all areas. the presence of antibodies in short-lived avian species and in young unvaccinated horses and the demonstration of seroconversions in horses ...19852863991
possible involvement of receptors in the entry of kunjin virus into vero cells.the results obtained from electron microscopy, adsorbed and internalised virus assays and immunofluorescence studies supported that the most likely mode of entry of kunjin virus into vero cells was by receptor-mediated endocytosis. this was deduced indirectly from the time sequence of events that occurred. electron microscopy revealed that endocytosis of the virus through coated vesicles had occurred. the adsorbed and internalised virus assay and immunofluorescence studies showed that there were ...19882899998
antibody prevalence of st. louis encephalitis virus in avian hosts in los angeles, california, 1986.a study was conducted to determine the pattern of st. louis encephalitis (sle) virus activity in the avian populations of the los angeles metropolitan area in 1986. in total, 679 birds of 42 species were captured at 7 study sites. the overall prevalence of sle neutralizing (n) antibody of 3% indicated enzootic transmission. antibody prevalences were higher in birds sampled in the central part of the metropolitan area, which was consistent with other epidemiologic data. the use of specific avian ...19882852209
yellow fever virus proteins ns2a, ns2b, and ns4b: identification and partial n-terminal amino acid sequence analysis.a series of fusion proteins corresponding to the hydrophobic ns2 and ns4 regions of yellow fever virus (yf) were generated in escherichia coli using trpe fusion vectors. antisera to ns2 and ns4 region fusion proteins recognize virus-specific proteins of 15 and 27 kda, respectively. n-terminal amino acid sequence analysis of the 27-kda protein indicates that the n-terminus of yf ns4b immediately follows a signalase-like cleavage site. additional sequence data generated by microsequence analysis o ...19892922923
potiskum virus: enhancement of replication in a macrophage-like cell line.replication of potiskum virus was studied in p388d1 macrophage-like cell line in the presence and absence of subneutralizing concentrations of specific antiviral antibody. the cultures were infected at multiplicities of infection (moi) ranging from 0.4 to 0.0004. the virus replicated to high titres at all moi tested, but there was an enhancement of virus replication in cultures supplemented with the antibody. enhancement of replication was moi dependent, the highest ratios being obtained in cult ...19872894139
terminal sequences of the replicative form of rna of the japanese encephalitis virus.the 5' and 3' terminal sequences of the replicative form (rf) of rna of a flavivirus, the japanese encephalitis (je) virus, strain ja0ars982, have been determined by in vitro labelling and mobility shift analysis. the plus strand sequence was 5'agaaguuuaucugugugaa...ucuoh3', while the minus strand sequence was 5'agauccuguguucuuccuca...ucuoh3'. these sequences were similar to those of west nile (wn) virus being identical in 12 nucleotides at the 5'terminal of the minus strand, and in the 5'termin ...19882897776
detection of dengue virus rna using nucleic acid hybridization.conditions for using slot-blot nucleic acid hybridization to quantitatively detect dengue-2 virus using a radiolabelled cdna probe, pvv17, were determined. as little as 11 plaque-forming units of virus were detected using a hybridization mixture without formamide and performing the test at 70 degrees c. while predominantly serotype-specific using stringent (65 degrees c) washing conditions, the probe detected all four dengue virus serotypes using astringent (28 degrees c) washing conditions. no ...19872881940
antigenic classification and taxonomy of flaviviruses (family flaviviridae) emphasizing a universal system for the taxonomy of viruses causing tick-borne encephalitis.for many years the expression "tick-borne encephalitis (tbe) virus" has been used to denote viruses causing the clinical entity tbe. no virus with the name "tbe virus" has been registered in the international catalogue of arboviruses, the generally accepted reference for naming arthropod-borne viruses, and no formal agreement has been reached within the scientific community to use the expression "tbe virus"; this term is inaccurate for indicating the etiologic agent of the disease tbe and confus ...19882904743
formation of autoimmune effectors after transfer of virus-induced autoreactive precursors to syngeneic intact receptor animals.we verified the assumption that autoimmune responses underlie immunosuppression developing in the course of virus infection. it has been shown by adoptive transfer that administration of langat-virus-induced autoreactive lymphocytes (arl) to the syngeneic recipient is followed by accumulation of autoreactive effectors (ae) eliciting a graft-verus-host reaction (gvhr) in the syngeneic system (aegvhr). in addition, cytotoxic t-lymphocytes (aec) appeared against the syngeneic macrophages. this effe ...19872894142
the isolation of arboviruses including a new flavivirus and a new bunyavirus from ixodes (ceratixodes) uriae (ixodoidea: ixodidae) collected at macquarie island, australia, 1975-1979.pools of ticks, ixodes (ceratixodes) uriae collected between 1975 and 1979 at macquarie island, yielded 33 strains of at least 4 different viruses: nugget virus (kemerovo group), 1 strain; taggert virus (sakhalin group) 9 strains; a previously undescribed flavivirus, related to central european tickborne encephalitis virus, for which the name "gadgets gully" is proposed, 9 strains; a virus serologically related to the uukuniemi serogroup, family bunyaviridae, for which the name "precarious point ...19852984951
application of enzyme immunoassay on infected cells (eia-ic) for arboviruses.comparative titrations of alpha-, flavi- and bunyamwera viruses were made by eia-ic and according to cytopathic effect (cpe). specific enzymatic reactions appeared earlier and in higher titres than cpe. the titres of dengue type 1, mayaro, powassan and langat viruses measured by eia-ic were comparable to those measured by intracerebral inoculation of mice. the cross-reactivity testing of eia-ic among alphaviruses (chikungunya, sindbis and mayaro), flaviviruses (japanese encephalitis, murray vall ...19862881468
arthropod-borne virus zoonosis surveillance in the cape province: 1. prospective serological investigations for virus activity in the beaufort west and middelburg districts during 1981.in addition to the routine sero-epidemiological surveillance for arthropod-borne viral zoonoses in the cape province carried out by the department of medical microbiology and state health department of virology laboratory, we conducted a prospective serological investigation for virus activity during 1981 in two districts of the province, namely the beaufort west and middelburg districts, which experienced heavy rainfall during the first two months of that year. the approach used was to obtain p ...19852987499
modoc-like virus isolated from wild deer mice (peromyscus maniculatus) in alberta.small mammals were trapped in northeastern alberta, canada during 1976. blood samples from these animals were tested for virus by inoculation of suckling mice. blood clots from two deer mice yielded isolates of the same virus. the virus was related antigenically to a number of flaviviruses which have been isolated from mammals in central america and north america and was related most closely to modoc virus. physical, chemical, and biological properties of the virus were similar also to those of ...19852987550
characterization of protease cleavage sites involved in the formation of the envelope glycoprotein and three non-structural proteins of dengue virus type 2, new guinea c strain.amino terminal sequences of the envelope protein e and the three largest nonstructural proteins ns1, ns3, and ns5 of the new guinea c strain of dengue virus type 2 (den-2) were obtained by nucleotide and protein sequencing. clones were prepared containing cdna of den-2 virus in the plasmid puc8. the nucleotide sequences of viral cdna inserts were determined and the cdna of each clone positioned on the flavivirus genomic map by comparison of the deduced amino acid sequence with that of yellow fev ...19872952760
antibody-dependent enhancement of tick-borne encephalitis virus infectivity.fourteen mouse monoclonal antibodies raised against tick-borne encephalitis virus (tbev) and polyclonal antisera raised against six other flaviviruses, edge hill (ehv), japanese encephalitis (jev), langat (lgtv), louping ill (liv), west nile (wnv) and yellow fever (yfv), were tested for their ability to enhance the replication of tbev in cells of the mouse macrophage-like line p388 d1, and for their reactivity in elisa and haemagglutination inhibition (hi) tests. irrespective of their specificit ...19852991448
a focus assay method for japanese encephalitis virus using complement and anti-virus serum.a sensitive, quantitative, short-time, and reproducible focus assay for japanese encephalitis (je) virus is described. after 2 or 3 days of incubation, the infected cells were treated with anti-je virus serum and complement, and subsequently stained with trypan blue; then clear foci were produced. this method made it easy to titrate the infectivities not only of all seven je virus strains tested but also of west nile (wn), murray valley encephalitis (mve), and st. louis encephalitis (sle) viruse ...19852985940
the isolation of meaban virus, a new flavivirus from the seabird tick ornithodoros (alectorobius) maritimus in france.seven strains of a new flavivirus, for which the name of meaban virus is proposed, were isolated from the seabird tick ornithodoros (a.) maritimus collected during 1981 and 1982 in nests of herring gulls (larus argentatus) on islands of south brittany, france. the new virus was compared serologically with 65 other flaviviruses including tyuleniy virus and was found to be most closely related to, but different from saumarez reef virus, an agent previously isolated in australia and tasmania. some ...19852982352
characterization of west nile virus persistent infections in genetically resistant and susceptible mouse cells. ii. generation of temperature-sensitive mutants.long-term persistent infections were established with the flavivirus, west nile virus (wnv), strain e101, in embryofibroblast cultures derived from susceptible c3h/he and congenic-resistant c3h/rv mice. cultures were initially maintained by weekly subculture at 37 degrees, but at passage 6 sister cultures were shifted to 32 degrees. virus progeny titers were observed to increase after the shift to 32 degrees indicating the possible presence of temperature-sensitive mutants. temperature-sensitive ...19852981450
viral infections of little blue penguins (eudyptula minor) along the southern coast of australia.serum antibodies to strains of avian paramyxovirus and flavivirus were detected in little blue penguins sampled at port campbell and phillip island, victoria, australia. no antibody to newcastle disease virus (ndv) was detected in 267 sera collected, although one penguin captured for experimental studies had a hemagglutination-inhibition antibody titer of 2(4) to this virus. experimental studies showed that the avian paramyxovirus designated apmv-im and strain v4 of ndv were non-pathogenic for p ...19852993680
conditions for haemolysis by flaviviruses and characterization of the haemolysin.the 17d vaccine strain of yellow fever virus (yf 17d) was used to establish the optimal conditions for lysis of chick erythrocytes. tissue culture-grown, polyethylene glycol-concentrated virus showed peak activity at ph 5.4 in citrate buffer when incubated at 37 degrees c. a further two- to fourfold increase in titre was obtained by pretreatment of the chick erythrocytes with 250 micrograms/ml trypsin. these conditions were also shown to be optimal for japanese encephalitis (je), west nile (wn) ...19852995565
human antibody response to immunization with 17d yellow fever and inactivated tbe vaccine.the antibody response against flaviviruses tick-borne encephalitis (tbe), kyasanur forest disease (kfd), murray valley encephalitis (mve), west nile fever (wnf), japanese b encephalitis (je), dengue 2 (den-2), and yellow fever (yf) was studied in humans after administration of an inactivated tbe virus vaccine. individuals were either prevaccinated with 17d yellow fever (experimental group) or without any previous exposure to flaviviruses (control group). the appearance of serum titres of homolog ...19852995571
premortem isolation of saint louis encephalitis virus: case report and implications for hospital and laboratory personnel. 19852995935
powassan viral encephalitis: a review and experimental studies in the horse and rabbit.powassan virus strain m794, a member of the flavivirus genus known to infect man and animals in canada, was inoculated intracerebrally into rabbits and horses. no clinical signs were observed in rabbits, but widespread encephalitis resulted, characterized by lymphoid perivascular cuffing, lymphocytic meningitis, and lymphocytic choroiditis. in horses, eight days after inoculation, prominent neurological signs occurred and lesions were those of non-suppurative encephalomyelitis, neuronal necrosis ...19852996203
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