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a protective mechanism induced by live group b arboviruses against heterologous group b arboviruses independent of serum neutralizing antibodies or interferon. 19674378109
the isolation of ilhéus virus from man in panamá. 19674378148
experimental infection of red grouse with louping-ill virus (flavivirus group). i. the viraemia and antibody response. 1975167055
viraemia studies on the kyasanur forest disease human cases of 1966. 1975175006
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
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
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
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
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
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
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
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
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
[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
critical evaluation of kyasanur forest disease virus neutralizing antibodies found in bats (a preliminary report). 1976178594
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
genetic resistance to lethal flavivirus encephalitis. i. infection of congenic mice with banzi virus.adult 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
[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
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
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
"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
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
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
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
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
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
[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
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
absence of viruria in kyasanur forest disease patients. 197717291
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
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
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
[kedougou virus (ar d14701): a new arbovirus ("flavivirus") isolated in senegal (author's transl)]. 1978677616
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
emergence of a new arbovirus disease in brazil. i. isolation and characterization of the etiologic agent, rocio virus.in 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
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 epidemic.in 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
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
antibodies to kyasanur forest disease virus in bats in the epizootic-epidemic area and neighbourhood. 1978217820
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
reaction of rattus rattus wroughtoni to kyasanur forest disease virus. 1978207642
ixodid ticks of red spurfowls (galloperdix spadicea spadicea) in the kfd area, karnataka state. 1978220191
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
detection of antibodies to alphaviruses and flaviviruses in some migratory birds of the danube delta.data 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
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
[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
cultivation of tuleniy virus (strain murman) in vitro.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
in vitro translation of 42 s virus-specific rna from cells infected with the flavivirus west nile virus. 1979462816
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
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
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
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
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
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
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
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
[serological survey on the prevalence of arboviruses in man in forest and periforest environments of the region of lobaye (central african republic)]. 1979233526
studies on the transmission of kyasanur forest disease virus by partly fed ixodid ticks. 1979229077
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
[preliminary observations on the replication of rocio virus (togavirus, flavivirus) in the brain of newborn mice]. 1979549208
susceptibility of rousettus leschenaulti to infection with kyasanur forest disease virus--a note. 1979222671
transfer with dialysable transfer factor of t-lymphocyte cytolytic response to tick-bone encephalitis virus antigen in naive mice.transfer factor activity was demonstrated in the dialysable extract from lymphocytes from outbred donor mice, in which immunization with live attenuated langat (e5 "14") virus induced a stage of high resistance against challenge with virulent tick-borne encephalitis virus. administered to naive inbred recipient mice, the extract conveyed in them specific cytolytic activity, exerted by their t lymphocytes, as demonstrated by the 51cr release assay on tick-borne encephalitis virus-infected syngene ...19806111208
cross-reactive killer t lymphocytes in a flavivirus infection.splenocytes from mice immunized intravenously with one dose of langat or yellow fever viruses were cytotoxic for target cells infected with virulent tick-borne encephalitis (tbe) virus; cytotoxicity was measured by 51cr release from target l929 cells. no significant lysis of the tbe virus-infected taget cells with splenocytes from sindbis virus-infected mice was noted.19806106380
arboviruses of coastal south-eastern australia.during investigations of epidemic polyarthritis at nelson bay, new south wales, 12 strains of ross river virus, the causative agent, were recovered from pools of mosquitoes. in addition, the mosquito pools yielded 9 strains of the flavivirus edge hill, 4 strains of a bunyavirus, gan gan, 1 strain of an orbivirus tilligerry, and 1 strain of an ungrouped probable arbovirus, yacaaba. the latter 3 viruses were found to be antigenically distinct from previously recorded arboviruses. a case of epidemi ...19806108758
replication of flaviviruses: separation of membrane translation sites of kunjin virus proteins and of cell proteins. 19806251615
enhancement of dengue virus infection in monocytes by flavivirus antisera.enhanced dengue 2 virus (d2v) infection in suspension cultures of human peripheral blood mononuclear phagocytes (pbl) produced by subneutralizing concentrations of dengue antisera has been described previously. in this study, the enhancement phenomenon was found to be a general property of representative flavivirus antisera. all except one of 24 antisera, which had been raised by 1-3 injections of flaviviruses in rabbits, enhanced the growth of dengue 2 virus in human pbl. flavivirus antisera sh ...19806157332
wesselsbron disease: virological and serological studies in experimentally infected sheep and goats.adult sheep and goats and new-born lambs and kids were experimentally infected with a wesselsbron disease virus. the viraemia in lambs commenced approximately 27 h after infection and lasted on the average for 50 h. a febrile reaction, which was mostly biphasic, commenced several hours after the viraemia and outlasted it by 50 h. the viraemia in adult animals began about 50 h after infection and lasted for 30 h. the fever usually commenced several hours after the viraemia and, as in 3 cases out ...19806262694
transovarial transmission of murray valley encephalitis virus by aedes aegypti (l).in laboratory studies, murray valley encephalitis virus was transmitted transovarially by orally infected aedes aegypti to approximately 1.5% of both adult male and female progeny.19806263238
[serological evaluation of vaccine against human encephalitis caused by rocio virus]. 19806258211
nomenclature of flavivirus-specified proteins.flavivirus structural proteins are designated e, c, and m, replacing the former nomenclature of v3 (envelope), v2 (core), and v1 (membrane-like) proteins, respectively. the nonstructural proteins, formerly nv1 through nv5, are designated by their apparent size in kilodaltons, prefixed by p (or gp if a glycoprotein), if they are stable unrelated end-products; the lower case p or gp is used for variants or uncharacterized products. a relationship to any structural protein is indicated by adding e, ...19806259086
[the course of flavivirus infections in mice in the presence of the graft versus host reaction under conditions of 2-way incompatibility].the graft versus host reaction (gvhr) under conditions of two-way incompatibility was shown to increase average longevity (al) of mice with experimental tick-borne encephalitis (tbe) and to activate asymptomatic infection caused by langat virus. experiments with tbe virus demonstrated participation of viable t lymphocytes in gvhr. inhibition of function of both humoral and cellular immunity was shown to occur in gvhr. the assumption that the increase in the average longevity in tbe is associated ...19806247848
enzyme linked immunosorbent assay (elisa) using beta-lactamase for the detection of antibodies to kfd virus. 19806248460
serological response to formolized kyasanur forest disease virus vaccine in humans at sagar and sorab talukas of shimoga district. 19806249824
comparison of haemagglutination inhibition (hi) and indirect fluorescent antibody (ifa) techniques for the serological diagnosis of certain flavivirus infections.paired serum samples from 25 patients having clinical evidence of arboviral infections and 15 controls were examined for antibodies against dengue, japanese encephalitis and west nile viruses by haemagglutination inhibition (hi) and indirect fluorescent antibody (ifa) methods. the two tests were comparable in specificity but the ifa test was found to be more sensitive than the hi test. like the hi test, the antibodies detected by ifa test cross-reacted within the flavivirus group under test. use ...19806249938
[comparative characteristics of reproduction of getah and west nile viruses in cell cultures of mosquitoes of 3 species]. 19806252429
a micro-neutralization test for flavivirus antibodies.a micro-neutralization test for the detection of flavivirus antibodies is described. the test utilizes the ps line of cells in flat bottomed microtiter plates to detect the neutralization of cytopathic effect by specific antibodies. cross-neutralization of flaviviruses found in southeast asia with homologous and heterologous hyperimmune mouse ascitic fluids revealed the test to be specific. the test is simple and inexpensive to perform.19806254186
development of a kit for the assay of haemagglutination inhibition antibodies to flaviviruses using formalinized goose erythrocytes.haemagglutination inhibition (hi) test using goose erythrocytes (grbc) is the method of choice for screening antibodies to various arboviruses. this test makes use of fresh grbc preserved in dextrose-gelatin-veronal (dgv). we have tried formalinizing grbc and have found that such cells can retain the surface property of being agglutinated by arboviruses and, therefore, can be used in haemagglutination (ha) and hi tests. unlike fresh cells preserved in dgv, formalinized cells can be preserved for ...19806254214
serological survey for human arbovirus infections in the province of quebec. 19806256047
method to detect asymptomatic carriers of simian hemorrhagic fever virus.evidence was obtained that mononuclear phagocytic cells are the target cells for simian hemorrhagic fever virus replication. using peritoneal macrophages from rhesus monkeys in an in vitro, 18 of 20 asymptomatic chronically infected patas monkeys were detected from coded samples. the two chronically infected patas monkeys not detected by the test, nevertheless, contained virus. this was determined by inoculating macrophage cultures with plasma from macaques dying as a result of inoculation with ...19806257971
turkey meningo-encephalitis in south africa.turkey meningo-encephalitis is a neuroparalytic disease of turkeys first described and shown to be caused by a flavivirus in israel. during 1978 a similar disease was observed in south africa. in addition to the lesions described in israel, myocarditis, regression of the ovary and egg peritonitis were constant findings. the similarity in host range, symptoms and pathological changes produced by the virus isolated locally and in israel and the serological cross-reaction between the 2 virus isolat ...19806251413
replication of tbe and langat viruses in cells from immune individuals.the replication of tbe virus and langat virus in cells of immune and non-immune individuals was compared in phytohemagglutinin (pha)-stimulated and non-pha-stimulated cultures and also following infection with low and high infection multiplicity. following infection of spleen cells from langat-immune mice with langat virus having a high infection multiplicity, higher virus replication rates than in non-immune cells were found to be present. replication of langat virus was generally superior to t ...19806252718
variation in virulence for mice and rhesus monkeys among st. louis encephalitis virus strains of different origin.the virulence characteristics of 67 strains of st. louis encephalitis (sle) virus isolated from various sources in north, middle, and south america were compared in mice and rhesus monkeys. each virus strain was titrated in mice exactly 21 days old and virulence was expressed as the ratio of intracerebral (ic)/intraperitoneal (ip) ld50. virus strains fell into three groups: 1) high virulence (ic/ip ld50 ratio approximately 1.0); 2) intermediate virulence (variable mortality over a wide dose rang ...19806254384
towards prediction and surveillance of murray valley encephalitis activity in australia.current practices for early warning of activity of murray valley encephalitis and other medically-important arboviruses are reviewed with view to improvement. data from previous papers on culex annulirostris populations, environmental factors and virus infection rates were reanalysed and the results considered as a basis for prediction and surveillance. this goal will only be achieved with improved national cooperation, a better epidemiological understanding and greater knowledge of the bionomic ...19806255919
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