buoyant density of some togaviruses in sucrose density gradient and capacity of their haemagglutinin fractions to interact with antibody.the buoyant densities of western equine encephalomyelitis virus (an alphavirus) and tick-borne encephalitis (tbe) virus (a flavivirus) antigens prepared by different methods were studied. sucrose density centrifugation revealed a heterogeneity in the density of the virions. the sedimentation pattern and height of peaks of the haemagglutinating activities and infectivity, other conditions being equal, depended both on the virus species and properties of its strains and on the mode of preparation ...197611662
effects of tilorone hydrochloride on experimental flavivirus infections in mice.the effect of tilorone hydrochloride on experimental infections of mice with west nile, langat and dengue type 2 viruses were studied. the drug significantly reduced the mortality after intraperitoneal inoculation of west nile virus, but failed to affect intracerebral infection with langat or dengue viruses. tilorone partially reversed cyclophosphan-enhanced mortality after extraneural inoculation of west nile and langat viruses. the possible modes of action of tilorone, interferon-inducing abil ...197717279
absence of viruria in kyasanur forest disease patients. 197717291
transmission of kyasanur forest disease virus by rhipicephalus haemaphysaloides ticks.larvae of rhipicephalus haemaphysaloides were infected with kaysanur forest disease (kfd) virus by feeding on viraemic rodents and reared into next generation larvae. fed larvae, nymphs, unfed adults, fed adult males, and females after oviposition were found infected, while the larvae were found free from infection. nymphs and adults transmitted the infection by bite to rodents and rabbits respectively. the virus was also passed through a second rodent-tick cycle. adult ticks showed a titre of 3 ...197827975
chemically-induced temperature sensitive mutants of dengue virus type 2. i. isolation and partial characterization.temperature sensitive (ts) mutants of dengue virus type 2 (den-2, th-36 isolate) were induced by replication in primary hamster kidney cells treated with 5-azacytidine. seven ts mutants were obtained from 138 clones isolated by an immunofluorescent cloning technique. of these 7 ts mutants, 5 were sufficiently stable to permit partial characterization. complementation was detected at very low but statistically significant levels between some ts mutants at 40 degrees c. viral double-stranded rna p ...197656929
antigenic characterization of flavivirus structural proteins separated by isoelectric focusing.isoelectrofocusing of nonionic-detergent-disrupted flaviviruses separated the envelope glycoprotein of 53,000 to 58,000 daltons and the nucleocapsid protein of 14,000 daltons. the envelope protein and nucleocapsid protein were isolated at isoelectric points of pi 7.8 and 10.3, respectively. the antigenic determinants of st. louis encephalitis, japanese encephalitis, and dengue virus envelope and nucleocapsid proteins were examined by solid-phase competition radioimmunoassay. by the appropriate s ...197769040
the isolation of saumarez reef virus, a new flavivirus, from bird ticks ornithodoros capensis and ixodes eudyptidis in australia.strains of a new flavivirus, for which the name saumarez reef virus is proposed, were isolated from seabird ticks collected from four localities. two strains were isolated from ticks of the species ornithodoros capensis neumann 1901 collected from the nests of sooty terns, sterna fuscata linnaeus 1766 on coral cays off the east coast of queensland, australia. the other three strains were isolated from ticks of the species ixodes eudyptidis maskell 1885 taken from two dead silver gulls larus nova ...197775000
attempts to reproduce amyotrophic lateral sclerosis in laboratory animals by inoculation of schu virus isolated from a patient with apparent amyotrophic lateral sclerosis.a virus isolated from the csf of a patient who had amyotrophic lateral sclerosis for 7 years, and prolonged pleocytosis in the csf, was adapted to suckling mouse brain by subsequent serial blind passages. this schu virus belongs to the tick-borne encephalitis complex of the genus flavivirus (togaviridae). suckling mouse brain homogenate of the 13th passage was used for transmission experiments in various species of laboratory animals. golden hamsters infected subcutaneously fell ill after a numb ...197984063
discontinuous counter-immunoelectrophoresis in the study of viruses.a method for the use of the discontinuous counter-immunoelectropnoresis (dcie) technique in the study of viruses of the major taxonomic groups is reported. the method was successfully employed in detection of antigen of viruses in the bunyavirus, bunyavirus-like, flavivirus, orbivirus, and rhabdovirus groups, and/or of antibody to these agents. although less sensitive than the complement fixation test, the dcie test was found to be rapid and in some cases more specific in differentiating related ...197897243
"karshi" virus, a new flavivirus (togaviridae) isolated from ornithodoros papillipes (birula, 1895) ticks in uzbek s.s.r.three identical strains of an arbovirus were isolated from 475 ornithodoros papillipes ticks collected in june, 1972, in burrows of the great gerbil (rhombomys opimus licht., 1882) in the environs of beshkent, karshinsk steppe, uzbek s.s.r. the isolate was found to range among flaviviruses. complement-fixation, agar diffusion precipitation and neutralization tests is tissue culture and mice indicated a one-way antigenic relationship between the isolate and west nile virus. however, the pattern o ...1976130853
experimental infection of red grouse with louping-ill virus (flavivirus group). i. the viraemia and antibody response. 1975167055
influence of certain immunodepressants on experimental flavivirus and enterovirus infections in mice.the effects of cyclophosphamide and 1,3-(piperidinomethyl)-5-phenyl-5-ethylbarbituric acid on certain flavi- and enterovirus infections in mice were studied. differential enhancement of mortality rates after extraneural and, less markedly, intracerebral virus inoculation was noted. while depression of humoral and/or cell-mediated immunity is considered to be responsible for the effects observed in flavivirus infections, impaired function of the reticuloendothelial system seems to contribute main ...1975172474
viraemia studies on the kyasanur forest disease human cases of 1966. 1975175006
critical evaluation of kyasanur forest disease virus neutralizing antibodies found in bats (a preliminary report). 1976178594
susceptibility of vandeleuria oleracea bennet, 1832 (rodentia, muridae) to experimental infection with kyasanur forest disease virus. 1976184037
susceptibility of hystrix indica kerr, 1792, indian crested porcupine (rodentia hystricidae) to kfd virus. 1976191392
susceptibility of lepus nigricollis cuvier, to experimental infection with kyasanur forest disease virus. 1977193782
correlation between the number of persons suffering from kyasanur forest disease and the intensity of infection in the tick population. 1977200556
reaction of rattus rattus wroughtoni to kyasanur forest disease virus. 1978207642
replication of dengue and junin viruses in cultured rabbit and human endothelial cells.the flavivirus dengue and the arenavirus junin are both associated with a hemorrhagic shock syndrome in man. we have demonstrated the replication of these viruses in vitro in both rabbit and human endothelial cells by viral titers and immunofluorescent antibody studies. rabbit endothelium established in continuous culture was derived from vena cava, while human cells in primary culture were derived from umbilical veins. in rabbit endothelium, dengue-2 virus passaged through monkey kidney monolay ...1978208980
[2 aspects of immunity in experimental flavivirus infections].experimentally, two aspects protective and damaging, of the immune response were demonstrated in the course of development of infection in mice inoculated with tickborne encephalitis (tbe) virus, langat, yellow fever, dengue type 2 or west nile viruses. the experiments were carried out in animals in which the functions of t- and b-lymphocytes, were temporarily inhibited with cyclophosphane (cp). it was demonstrated that the protective or damaging role of the immune response depended on the metho ...1978211731
studies of louping-ill virus (flavivirus group) in wild red grouse (lagopus lagopus scoticus).studies were made to find evidence of louping-ill virus infection in free-living red grouse and relate this to their breeding success. in areas where ticks were abundant 61 (84%) adult grouse had antibody to the virus compared with 1 (10%) in areas where ticks were relatively scarce. of 162 chicks tested 25 were shown to be viraemic. infected chicks were of significantly less weight than comparably aged uninfected birds and the probability that they died was much greater than that of uninfected ...1978212479
antibodies to kyasanur forest disease virus in bats in the epizootic-epidemic area and neighbourhood. 1978217820
ixodid ticks of red spurfowls (galloperdix spadicea spadicea) in the kfd area, karnataka state. 1978220191
susceptibility of rousettus leschenaulti to infection with kyasanur forest disease virus--a note. 1979222671
dimethyl sulfoxide enhancement of phlebotomus fever virus plaque formation.dimethyl sulfoxide (dmso)incorporated into an agar overlay containing deae-dextran enhanced plaque formation in vero cells by naples sandfly fever virus passaged in mouse brain or vero cell cultures. no plaques were visible when dmso was used without the deae-dextran, some plaques were rarely visible (less than 0.5mm) when deae-dextran was used without the dmso, and up to 10-fold more plaques were clearly visible (0.5-1.5 mm) when both chemicals were used. the combined enhancing effect of dmso a ...1979223461
susceptibility of common giant flying squirrel to experimental infection with kfd virus. 1979229076
studies on the transmission of kyasanur forest disease virus by partly fed ixodid ticks. 1979229077
[serological survey on the prevalence of arboviruses in man in forest and periforest environments of the region of lobaye (central african republic)]. 1979233526
experimental mixed infection with two tick-borne viruses and interferon-mediated interference.tick-borne encephalitis virus (tev), a flavivirus, and lipovník virus (lv), a member of the kemerovo group and complex and possible member of the rioviridae, were used to infect chick embryo cell (cec) cultures. lv reproduction was inhibited by preinfection with tev, mainly in aged cultures. in young cec cultures, tev production was stimulated slightly and interferon was sometimes depressed by this superinfection; on the contrary, in aged cultures the superinfecting lv stimulated interferon also ...1975235191
reactions of purified hemagglutinating antigens of flaviviruses with 19s and 7s antibodies.the rapidly sedimenting hemagglutinin (rha) representing the purified virion and the slower-sedimenting hemagglutinin (sha) of several flaviviruses were separated and used in hemagglutination inhibition tests with the 19s (immunoglobulin m) and 7s (immunoglobulin g) immunoglobulin fractions of rabbit antisera, prepared against purified viral antigens or against crude virus pools. the antibody specificity in tests with rha was identical to the specificity in those employing sha. 7s antibody cross ...1975235489
t cell-mediated cytotoxicity for l 929 fibroblasts infected with banzi virus (flavivirus).during infection with banzi virus, splenic thymus-derived cells of c3h/rv mice developed immunologically specific cytotoxicity for banzi virus-infected, c3h-derived l 929 fibroblasts. cytotoxic activity was detected by six days after viral inoculation, was maximal by eight days, and decreased to background levels by 16 days. there was no consistently significant difference in banzi virus-specific cytotoxicity of spleen cells from c3h/rv and c3h/he mice, which are genetically resistant and suscep ...1979315440
cultivation of tuleniy virus (strain murman) in vitro culturability of murman strain of tuleniy flavivirus isolated recently in the northern regions of the ussr was studied. stable ps pig kidney line was found suitable as a primary sensitive cell substrate for the isolation, proliferation and serial propagation of the virus. the pronounced pathogenicity of the virus to ps cells permits the testing of its infective activity comparable with i.c. titrations on mice, vnt in vitro and the plaquing technique. ps line is suitable for the demonstr ...1978363936
dengue virus infections in nigeria: a survey for antibodies in monkeys and humans.a retrospective serological survey for dengue immunity was conducted in nigeria to determine the prevalence of infection in man and non-human primates. preliminary haemagglutination-inhibition (hi) tests revealed that 63% of persons tested had hi antibodies against one or more of the following flaviviruses: dengue type 1, yellow fever, west nile and wesselsbron. parallel hi and neutralization (n) tests on 179 human sera showed that six of 20 sera (30%) negative for flavivirus hi antibody contain ...1977404737
serologic examination of human population in south moravia (czechoslovakia) on the presence of antibodies to arboviruses of the alfavirus, flavivirus, turlock groups and bunyamwera supergroup.a statistically representative group of human population from the south moravian region (cssr) was examined on the presence of antibodies against the following arboviruses: lednice, sindbis, tick-borne encephalitis, west nile, tahyna and calovo. the ascertained absence of antibodies to the lednice virus is an evidence that at present this virus is of no epidemiological importance in the region studied. no antibodies to sindbis, west nile and calovo viruses were demonstrated. 17.8 to 42.0% of ant ...1979447128
isolation of st. louis encephalitis virus in south brazil.eight strains of a flavivirus identified as st. louis encephalitis (sle) virus were isolated from wild rodents, birds, and sentinel mice in three locations in the state of são paulo, brazil from 1967--1969. no illness attributable to sle virus infection was detected among the local inhabitants, although about 5% of the local population had neutralizing antibodies to this virus.1979453451
in vitro translation of 42 s virus-specific rna from cells infected with the flavivirus west nile virus. 1979462816
proteins specified by togaviruses in infected aedes albopictus (singh) mosquito cells.yields of greater than 10(7) p.f.u./ml at 28 or 37 degrees c of the alphavirus sindbis and the flavivirus kunjin were obtained in the aedes albopictus (singh) cell line, the latent periods being 4 to 6 and 10 to 12 h, respectively. despite a high background of host protein synthesis, virtually all the virus-specified proteins of the flaviviruses kunjin, dengue-2 and japanese encephalitis were labelled and resolved by slab gel electrophoresis of infected and uninfected cell proteins. in contrast, ...1979479844
zika virus infections in nigeria: virological and seroepidemiological investigations in oyo state.a study of zika virus infections was carried out in four communities in oyo state, nigeria. virus isolation studies between 1971 and 1975 yielded two virus isolations from human cases of mild febrile illness. haemagglutination-inhibition tests revealed a high prevalence of antibodies to zika and three other flaviviruses used. the percentages of positive sera were as follows: zika (31%), yellow fever (50%), west nile (46%), and wesselsbron (59%). neutralization tests showed that 40% of nigerians ...1979489960
antibody-mediated enhancement of flavivirus replication in macrophage-like cell lines.interactions between animal viruses and antiviral antisera may exceptionally result in an apparent increase in viral infectivity. halstead and coworkers demonstrated enhanced replication of dengue virus (a flavivirus, family togaviridae) in human or simian peripheral blood leucocytes carrying fc receptors at subneutralising concentrations of antidengue antibody. we have used three continuous cell lines which express macrophage markers to explore the mechanism of this phenomenon. dengue virus fai ...1979503230
protease treatment and chemical crosslinking of a flavivirus: tick borne encephalitis virus.tick-borne encephalitis virus was treated with pronase or thermolysin. the resulting particles were banded in sucrose gradients and analyzed for polypeptide composition. both enzymes caused a reduction in particle density from 1.19 to 1.15--1.16 g/cm3. no loss of viral lipid or nucleic acid could be observed. sds-polyacrylamidegel electrophoresis showed that only the core protein v2 was unchanged whereas the envelope proteins v3 and v1 had disappeared from their original positions in the page pr ...1979508094
a comparative study of tick-borne encephalitis virus rna synthesis in acutely and persistently infected cells.rate zonal and buoyant density gradient centrifugation did not reveal any difference between tick-borne encephalitis virus virions released from acutely or persistently infected cells. all three rna species characteristic for flavivirus replication were found both in acutely or persistently infected cells, but increased levels of intracellular 42s rna polyadenylation was observed in persistently infected cells.1979518305
[preliminary observations on the replication of rocio virus (togavirus, flavivirus) in the brain of newborn mice]. 1979549208
[protective effect of cellular immunity in experimental flavivirus infections].experiments were conducted with the tick-borne encephalitis (te) virus; confirmation of a protective action of cellular immunity in mice was obtained. administration of sensitized splenocytes to the animals together with the virus was accompanied with an increase of their mean survival or with the reduction of mortality in comparison with control animals given nonimmune or destroyed cells. the protective action of the effector cells was not connected with the intensification of antibody formatio ...1977596025
togavirus rna: reversible effect of urea on genomes and absence of subgenomic viral rna in kunjin virus-infected cells.electrophoretic analyses showed that no rnase-sensitive rna smaller than the genome was specified by the flavivirus kunjin in infected vero cells during the period of maximum rna and protein synthesis. in contrast, rna extracted from sindbis virus-infected cells under similar conditions included the expected 42s rna (equivalent to the genome) and the smaller 26s (interjacent) rna. treatment of the genome of both togaviruses with 12 m urea produced a reversible (possibly conformational) change; m ...1977597036
togaviridae.the family togaviridae is described; it contains four genera--alphavirus, flavivirus, pestivirus and rubivirus--and additional members. the main characteristics of the family are as follows: single-stranded, linear rna, molecular weight about 4 x 10(6). virions have isometric nucleocapsids surrounded by a lipoprotein envelope containing host cell lipid and virus-specified polypeptides including one or more glycopeptides. virions yield infectious rna. there are at least 80 members; all the alphav ...1978618831
identification of saint louis encephalitis virus mrna.saint louis encephalitis (sle) virus-specific rna was recovered from infected hela cells by sodium dodecyl sulfate (sds)-phenol-chloroform extraction, and the molecular species were resolved by sds-sucrose gradient centrifugation and agarose gel electrophoresis. sucrose gradient centrifugation revealed the presence of a 45s species, minor 20 to 30s heterogeneous species, and an 8 to 10 s rna species in the cytoplasmic extract. analysis of the same samples by electrophoresis on agarose gels, unde ...1978625082
isolation of st. louis encephalitis virus from overwintering culex pipiens mosquitoes.two strains of st. louis encephalitis virus were isolated from overwintering mosquitoes collected in maryland and pennsylvania during january and february 1977. there isolations from culex pipiens constitute evidence that a mosquito-borne flavivirus can persist in a vector mosquito in temperate climates during the winter season.1978628843
emergence of a new arbovirus disease in brazil. i. isolation and characterization of the etiologic agent, rocio april, 1975, an epidemic of human encephalitis was detected in several counties in the state of são paulo, brazil; the epidemic continued into 1976. a virus was isolated from central nervous system (cns) tissues of a 39-year-old male who died on december 8, 1975; the virus was found to be a new flavivirus for which the name rocio virus is proposed. nine further isolations of rocio virus were obtained from cns tissues of 17 patients who died with clinical symptoms of encephalitis. isolations o ...1978665659
detection of antibodies to alphaviruses and flaviviruses in some migratory birds of the danube are reported on the presence of antibodies to some group a(alphavirus) b(flavivirus) arboviruses in 8 species of migratory birds (ardea cinerea, plegadis falcinellus, anas querquedula, anser albifrons, gavia arctica, fulica atra, larus minutes and and phalacrocorax corbo) of the danube delta.1978676070
[kedougou virus (ar d14701): a new arbovirus ("flavivirus") isolated in senegal (author's transl)]. 1978677616
morphological demonstration of the virus of tick-borne encephalitis in the human brain.a case is presented in which the fourfold increase of the hi titer during the progression of the disease, and an increase in igm content found at the beginning of the second week of the disease confirmed the diagnosis of tick-borne encephalitis. the light microscopic changes correspond to the findings accepted as characteristic to tick-borne encephalitis. viruses, morphologically belonging to the flavivirus genus were found by electron microscopy in the thalamus, substantia nigra, and cerebellum ...1978696243
emergence of a new arbovirus disease in brazil. ii. epidemiologic studies on 1975 april, 1975, an outbreak of human encephalitis caused by rocio virus, a new flavivirus, occurred in the coastal region of southern são paulo, brazil. the epidemic started during the second half of march, 1975, and ended in june, 1975. a total of 465 cases with 61 deaths were recorded, and the overall attack rate was 15 per thousand population. the mortality rate was two per thousand inhabitants and the overall case-fatality rate was 13%. however, the case-fatality rate was markedly decreased ...1978727209
a comparative study on translation of flavivirus and picornavirus rnas in vitro: apparently different modes of protein synthesis. 1978729787
genetic resistance to lethal flavivirus encephalitis. i. infection of congenic mice with banzi c3h/rv mice were highly resistant and adult c3h/he mice were highly susceptible to lethal encephalitis after intraperitoneal inoculation of banzi virus (flavivirus), but the infectivity of the virus was the same for both strains of mice. yields of virus were similar from lymphoid tissues of c3h/he and c3h/rv adult mice, but titers of virus in the brain were significantly lower in c3h/rv mice. lesions of encephalitis developed in both strains but remained mild and self-limiting in c3h/rv mi ...1976787444
genetic resistance to lethal flavivrus encephalitis. ii. effect of immunosuppression.genetic resistance of c3h/rv mice to lethal infection with banzi virus (flavivirus) was severely compromised by immunosuppression with cyclophosphamide, sublethal x-irradiation, or thymus (t-) cell depletion. the mortality rate among immunosuppressed mice was usually 100%, but average survival times were shorter for mice treated with cyclophosphamide or for x-irradiated mice (10 days) than for t-cell-depleted mice (17 days). mice treated with cyclophosphamide had high titers of virus in brain, l ...1976787445
[a rapid assay of sindbis virus infectivity by counting immunofluorescence foci in "aedes albopictus" cell culture (author's transl)].the aedes albopictus cell line is susceptible to numerous arboviruses but the appearance of cytopathic effect is observed mostly with flavivirus. a method of rapid titration of sindbis virus by counting immunofluorescent foci is described, using this cell line.1976799476
the proteins of murray valley encephalitis virus.proteins specified by murray valley encephalitis virus were labelled during virus growth in vero and in ps cells, and separated by polyacrylamide gel electrophoresis. the purified virus particle contains three proteins (v-1, v-2 and v-3) whereas the slow sedimenting haemagglutinin or virus sub-particle lacks the core protein v-2 but contains nv-2, a non-structural protein. seven non-structural proteins in addition to v-2 and v-3 were identified in infected cells. electrophoretic profiles by viru ...1975806663
[transovarian transmission of a flavivirus, the koutango virus, in aedes aegypti l].the koutango virus dak an d 5443 isolated from rodents of the genus tatera belongs to the genus flavivirus of the faily togaviridae. this virus is very similar to the yellowfever, virus. it is experimentally transmitted from young mouse to young mouse by aedes aegypti. the following observations show on one hand that this virus is found in the eggs of infected a. aegypti and on the other that the females from these eggs transmit the virus to the young mouse by biting them.1976827342
heterogeneity among flavivirus proteins separated in slab gels.35s-methionine-labeled proteins specified in vero cells by flaviviruses were analysed by sds-phosphate electrophoresis in polyacrylamide slab gels. the clarity of the profile produced by kunjin virus permitted designation of the nonstructural proteins, and confirmed the identity of nv21/2; the profile included a protein previously designated v2 (core protein) but now named nv11/2 because it migrates perceptibly faster than v2. despite a varying background of labeled host proteins, identifiable p ...1977869717
immune response in rabbits to virion and nonvirion antigens of the flavivirus kunjin.the nature of the antibodies formed in rabbits in response to the following kunjin virus antigens was examined: infectious suckling mouse brain (smb), purified virion or rapidly sedimenting hemagglutinin (rha), slowly sedimenting hemagglutinin (sha), and envelope fragments prepared from rha disrupted by 0.1 or 0.2% sodium deoxycholate (doc). the hemagglutination-inhibiting (hi) and neutralizing antibody responses to smb, rha, and large envelope fragments (0.1% doc) were remarkably uniform, antib ...1977870434
proteins and glycoproteins specified by the flavivirus kunjin. 1977888348
strategy of the flavivirus genome: evidence for multiple internal initiation of translation of proteins specified by kunjin virus in mammalian cells. 1977888349
immune electron microscopy of arboviruses.representative members of four arbovirus taxons were studied by immune electron microscopy (iem) in an attempt to determine whether the technique can be applied to the specific identification of arboviruses. alphavirus, flavivirus, bunyavirus, and rhabdovirus antigens were prepared by propagation in tissue culture. the viruses were used to titrate homologous antibody and test heterologous antibody in the iem test. specific clumping together with visualization of antibody attachment was observed ...1977889020
[reproduction and interferogenic activity of togaviruses].a comparative study of the correlation between reproduction and the interferon-inducing activity of viruses in chick embryo fibroblast cultures was carried out with members of different groups of togaviruses: alphavirus (venezuelan equin encephalomyelitis viru, vee) and flavivirus (saint louis encephalitis virus, sle). the correspondence between cycles of accumulation of intracellular and extracellular viruses and the dynamics of interferon production the synthesis of which began early in the st ...1977898898
persistent infection of cultured mammalian cells by japanese encephalitis virus.persistent infections were established by serial undiluted passage of flavivirus japanese encephalitis virus in a line of rabbit kidney cells (ma-111). the persistently infected cells resembled uninfected cells in most respects. low levels of infectious virions were released from a small percentage of cells, and a larger and more variable percentage was shown to possess viral antigen by fluorescent-antibody staining. released viruses were shown to interfere with replication of wild-type japanese ...1977916028
unique peptide maps of the three largest proteins specified by the flavivirus kunjin.tryptic digests of four polypeptides found in kunjin virus-infected vero cells, nv5, nv4, v3, and nv3, were compared by peptide mapping. the polypeptides to be analyzed were labeled with radioactive methionine and separated by electrophoresis through polyacrylamide gels containing sodium dodecyl sulfate. because infection of vero cells by kunjin virus does not inhibit host cell protein synthesis, radioactively labeled viral polypeptides prepared from infected cells migrate coincidentally during ...1977916030
california encephalitis virus proliferation in yukon mosquitoes incubated at low temperatures.replication of a subarctic bunyavirus, california encephalitis (snowshoe hare subtype), was detected in salivary glands and thoraces of wild-caught aedes communis mosquitoes from the yokon territory, after intrathoracic inoculation with 0.1 to 100 mouse ld50 virus, and incubation for 7 to 21 days throughout their viable temperature range of 0 to 23 degrees c. immunoperoxidase staining confirmed that viral replication occurred in the cytoplasm of acinar cells of salivary glands, both by ligh micr ...1976963625
serological evidence of inter-epidemic infection of feral pigs in new south wales with murray valley encephalitis virus.the sera of 617 feral pigs, collected from three widely separated areas of northern and central new south wales, were examined for antibody to murray valley encephalitis (mve) virus and to ross river virus. haemagglutination-inhibition (hi) antibody was detected to mve in 58% of sera and to ross river virus in 15% of sera. neutralization tests suggested that the mve hi antibody resulted from infection with mve virus in the summers of 1971-1972 and 1972-1973 when the virus was not known to be act ...19761016127
ord river arboviruses--serological epidemiology.this paper presents the results of haemagglutination-inhibition tests carried out on sera from 441 persons, 1,080 cattle and 335 birds in the kimberley area. two alphaviruses (group a) (ross river and sindbis) and one flavivirus (murray valley encephalitis) were used for the preparation of haemagglutinins in the haemagglutination-inhibition tests. the tests showed a high percentage of antibody of murray valley encephalitis in humans, birds and cattle, with an obvious focus of infection in the st ...19761021093
experimental infection of red grouse with louping-ill virus (flavivirus group). ii. neuropathology. 19751170216
the damaging action of cellular immunity in flavivirus infections of mice.the development of acute infections caused by different flaviviruses was studied in immunosuppressed inbred and non-inbred mice. cyclophosphamide treatment of challenged animals resulted in an increase of the mean survival time by 24--144 hours in some but not all virus-mouse strain combinations. the transient protective action of cyclophosphamide was not due to suppression of the reproduction of tick-borne encephalitis (tbe) or dengue 2 (d2) virus in the brains of mice. in tbe or d2 infections ...19751207187
the basis of arbovirus classification.the biologically defined set of arboviruses contains well over 300 separate viruses which have been subdivided into some 40 serological groups on the basis of antigenic cross-reactivity. more than three quarters of all arboviruses can now bw placed into one of the following five major taxonomic genera based upon the fundamental properties of the virion: alphavirus, flavivirus, orbivirus, rhadovirus, bunyavirus. there are 20 alphaviruses, representing serological group a, and 57 flaviviruses in s ...19751207193
simian hemorrhagic fever virus: a new togavirus.using the prototype strain of shf virus, we have confirmed the nature of the genome (rna), the presence of an envelope (derived from an internal membrane), the virion size (45-50 nm), and probable cubic symmetry. we have also described four viral structural proteins and determined the phospholipid content of the virions. the known properties of shf virus suggest that it should be classified in the togavirus family, and possibly in the flavivirus group.19751208594
replication of the flavivirus kunjin: proteins, glycoproteins, and maturation associated with cell membranes. 19761258357
solid-phase radioimmunoassay for antibodies to flavivirus structural and nonstructural proteins.a micro-solid-phase radioimmunoassay (spria) is described for quantitation of antibodies to purified flaviviruses as well as to the purified envelope glycoprotein and 80,000-molecular-weight viral nonstructural protein. sera from mice experimentally infected with saint louis encephalitis (sle) virus or from humans after a primary sle virus infection reacted more specifically with the major viral envelope protein in the spria test than with antigens conventionally used in the complement fixation ...19761270142
the murray valley encephalitis virus prm protein confers acid resistance to virus particles and alters the expression of epitopes within the r2 domain of e study the role of the precursor to the membrane protein (prm) in flavivirus maturation, we inhibited the proteolytic processing of the murray valley encephalitis (mve) virus prm to membrane protein in infected cells by adding the acidotropic agent ammonium chloride late in the virus replication cycle. viruses purified from supernatants of ammonium chloride-treated cells contained prm protein and were unable to fuse c6/36 mosquito cells from without. when ammonium chloride was removed from the ...19921280384
[arbovirus antibodies in wild game caught in moravia].the hit method was used to examine blood serums of the game in moravia (roebuck, red deer, fallow deer, mouflon, wild boar, brown hare) for the presence of antibodies to arboviruses of these groups: alphavirus (sindbis-sin), flavivirus (west nile-wn), tick-borne encephalitis (tbe) and bunyamwera (tahyna-tah, calovo-cvo). antibodies to all viruses were detected, and namely in these frequencies: sin 0.9%, wn 16.9%, tah 41.5%, cvo 23.1% and tbe 8.5%.19921292172
[early summer meningoencephalitis vaccination. the indications and a critical assessment of the neurological vaccination complications]. 19921309694
comparison of a dengue-2 virus and its candidate vaccine derivative: sequence relationships with the flaviviruses and other viruses.a comparison of the sequence of the dengue-2 16681 virus with that of the candidate vaccine strain (16681-pdk53) derived from it identified 53 of the 10,723 nucleotides which differed between the strains. nucleotide changes occurred in genes coding for all virion and nonvirion proteins, and in the 5' and 3' untranslated regions. twenty-seven of the nucleotide changes resulted in amino acid alterations. the greatest amino acid sequence differences in the virion proteins occurred in prm (2.20%; 2/ ...19921312269
hepatitis c: basic and clinical studies.the hcv, a single stranded rna virus belonging to the family of flavivirus, has been identified as the probable cause of the majority of cases of transfusion-associated nanb hepatitis and community-acquired nanb hepatitis in japan. the hepatitis virus is present in a least 2% of the blood donor population and is extremely common in high risk groups, such as hemophiliacs and hemodialysis patients. the contribution of hcv infection to sporadic, acute and chronic hepatitis, liver cirrhosis and prim ...19921313382
virus safety of human immunoglobulins: efficient inactivation of hepatitis c and other human pathogenic viruses by the manufacturing procedure.human immunoglobulins are plasma derivatives with a low risk of transmitting viral infections. to the present, no proven case of human immunoglobulins transmitting human immunodeficiency viruses has been reported. however, there have been a few reports on the transmission of hepatitis c virus by these plasma proteins. to improve further the safety of both 5s iv human immunoglobulins and 7s im immunoglobulins, we introduced a 10-hour heat treatment of the aqueous solutions at 60 degrees c (i.e., ...19921314286
immunogenicity of experimental live attenuated japanese encephalitis vaccine viruses and comparison with wild-type strains using monoclonal and polyclonal antibodies.a total of 105 hybridomas secreting anti-japanese encephalitis (je) virus monoclonal antibodies (mabs) were generated from six fusions against four strains of je virus: wild-type strains sa14 and g8924 and live attenuated vaccines sa14-5-3 and sa14-14-2 (pdk-9). most of the mabs (87%) elicited haemagglutination inhibition activity while only a minority (24%) elicited neutralization. none of the mabs prepared against sa14-5-3, parent of sa14-14-2, elicited neutralization while the only mabs prepa ...19921315470
cloning and sequence analysis of the genes encoding the nonstructural proteins of langat virus and comparative analysis with other flaviviruses.langat virus, a member of the family flaviviridae is antigenically very similar to highly pathogenic tick-borne encephalitis viruses. we cloned and sequenced the complete nonstructural gene-coding region of langat virus (strain tp21) and compared the deduced amino acid sequences of each nonstructural protein to those of other flaviviruses. by alignment with the reported amino acid sequences of the nonstructural proteins of several flaviviruses, we were able to predict proteolytic cleavage sites ...19921316684
new approaches to flavivirus vaccine development. 19921318137
combined simian hemorrhagic fever and ebola virus infection in cynomolgus monkeys.simian hemorrhagic fever (shf) virus and a new strain of ebola virus were isolated concurrently in recently imported cynomolgus monkeys (macaca fascicularis) being maintained in a quarantine facility. ebola virus had never been isolated in the u.s. previously and was presumed to be highly pathogenic for humans. a chronology of events including measures taken to address the public health concerns is presented. the clinicopathologic features of the disease were abrupt anorexia, splenomegaly, marke ...19921318446
inactivation of viruses related to hepatitis c virus by pasteurization in human plasma derivatives. 19921319182
a stochastic analysis of three viral sequences.this paper analyzes the nucleotide sequences of three viruses: kunjin, west nile, and yellow fever. each virus has one long open reading frame of greater than 10,200 nucleotides that codes for four structural and seven nonstructural genes. the kunjin and west nile viruses are the most closely related pair, when assessed on the basis of matches between their nucleotide sequences. as would be expected, the matching is least for bases at third-position codon sites and is greatest for second-positio ...19921321321
[transfusion-associated non-a, non-b, non-c hepatitis caused by flaviviruses].hepatitis c virus was shown to be a member of the flavivirus family. tick-borne encephalitis virus and west nile virus, members of the same family occur in hungary, too. serum samples from patients suffering from transfusion associated hepatitis were tested with yellow fever virus antigens for specific igg, and igm using immunofluorescence test. eight hundred serum samples were tested. yellow fever virus related igg antibodies were found in 232 sera. in the case of 72 patients specific igm antib ...19921321397
comparison of haemagglutination inhibition and indirect fluorescent antibody tests to detect certain flavivirus antibodies in equines.formalinized goose erythrocytes were used in haemagglutination inhibition (hi) and indirect fluorescent-antibody (ifa) tests to detect antibodies to japanese encephalitis (je) and west nile (wn) viruses in equines. paired serum samples from 31 cases having clinical symptoms of flaviviral infections (je and wn viruses) and 45 controls were examined. for hi test, formalinized goose erythrocytes were used as such, whereas in ifa test, formalinized goose erythrocytes were first coated with respectiv ...19921321546
isolation of kunjin virus from a patient with a naturally acquired describe the first isolation of kunjin virus from a patient with a natural infection.19921321945
a new genotype of japanese encephalitis virus from indonesia.primer-extension sequencing of the rna template of polio, dengue, rift valley fever, and japanese encephalitis (je) viruses has provided new information on their geographic distribution, origin, and evolution. in a previous study of 46 diverse je virus strains, we demonstrated the existence of three distinct je genotypes in asia. we now report the occurrence of a fourth genotype. in the present study, 19 je virus isolates, representing various geographic regions of asia and a 50-year time span, ...19921322071
the complete nucleotide sequence of cell fusing agent (cfa): homology between the nonstructural proteins encoded by cfa and the nonstructural proteins encoded by arthropod-borne flaviviruses.cell fusing agent (cfa) is an rna virus originally isolated from a line of aedes aegypti mosquito cells. although our characterization of the virus many years ago showed that it resembled the flaviviruses, there was no detectable serological cross-reaction with members of the genus flavivirus. furthermore, unlike the well-studied members of the genus flavivirus, cfa did not replicate in any of several vertebrate cell lines tested. we have now determined the nucleotide sequence of the cfa genome. ...19921322586
molecular and ultrastructural analysis of heavy membrane fractions associated with the replication of kunjin virus subcellular extracts of kunjin virus-infected cells prepared by lysis and differential centrifugation, the viral rna polymerase, rna and proteins were associated mainly with cytoplasm. when the cytoplasmic extract (500 g supernate) of infected cells labelled for 3 h from 24 h post-infection was further fractionated by rapid centrifugation through a sucrose density gradient, all viral products were located only in dense or "heavy membrane" fractions, which contained three types of virus-induce ...19921322651
heterologous resistance to superinfection by louping ill virus persistently infected cell cultures.louping ill virus, a tick-borne arbovirus readily established a persistent infection in porcine kidney (ps) cells after initially inducing minor cytopathic changes. nucleotide sequence analysis of the envelope glycoprotein of the viral rna recovered from the persistently infected cells showed no changes as compared with the virus used to establish persistent infections. more than 80 per cent of the cells contained virus specific antigen when analysed by indirect immunofluorescence microscopy. th ...19921322654
neuronal cell cultures as a model for assessing neurotoxicity induced by encephalitic viruses.primary dispersed and organotypic cultures were prepared from selected brain areas and spinal cords of rat (sprague-dawley) and mouse (sjl/ola(f) ness-ziona) fetuses and neonates. following fiber regeneration, synapse formation and myelination, cultures were infected with one of the following viruses: rabies cvs-21 strain, sindbis alphavirus, west-nile flavivirus and theiler murine encephalomyelitis virus. light and electron microscopical studies showed clear differences in the target cells for ...19921324447
molecular genetics of pestiviruses.recent developments in understanding the molecular genetics of pestiviruses are reviewed. the genomic rna of several pestiviruses has been molecularly cloned and sequenced. the genetic organization of the viral protein coding region has been refined, and the complete complement of virus-encoded proteins has been elucidated. viral gene expression involves both co-translational and post-translational precursor polyprotein processing. biogenesis of the virion structural proteins requires the proteo ...19921325329
nucleotide sequence of the envelope glycoprotein of negishi virus shows very close homology to louping ill virus.negishi virus, a member of the family flaviviridae, was originally isolated in japan, during an outbreak of japanese encephalitis. antigenically, however, negishi virus resembles the tick-borne rather than the mosquito-borne flaviviruses. monoclonal antibodies that bind louping ill virus showed a close antigenic relationship between louping ill and negishi virus. the genes encoding the envelope glycoprotein of negishi virus (strain 3248/49/p10) and louping ill virus (strain sb526) were cloned an ...19921326816
proteolytic processing of a murray valley encephalitis virus non-structural polyprotein segment containing the viral proteinase: accumulation of a ns3-4a precursor which requires mature ns3 for efficient processing.the proteolytic processing of a non-structural polyprotein segment from the cytoplasmic domain of ns2a to the c terminus of ns5 of murray valley encephalitis (mve) virus was examined, when expressed from cdna via a vaccinia virus recombinant, in transiently transfected cos cells, or synthesized by cell-free translation. cleavages mediated by the virus-encoded proteinase domain in ns3 at the junctions of ns2a-2b, ns2b-3 and ns4b-5 were catalysed efficiently. however, the cleavage at the ns3-4a ju ...19921328486
restimulated memory tc cells have a higher apparent avidity of interaction with targets than primary virus-immune tc cells as indicated by anti-cd8 blocking.previous experiments have shown that whereas a secondary in vitro kunjin-immune cytotoxic t (tc) cell population lysed equally well targets infected with either native flavivirus or a recombinant vaccinia virus expressing the immunodominant determinant, primary in vivo kunjin-immune tc cells were able to lyse only the recombinant vaccinia virus-infected targets. using cd8 blockade to assess the avidity of t cell-target interaction, recombinant-infected targets express antigen more efficiently th ...19921330899
Displaying items 1 - 100 of 3318