| characterization of nigerian strains of west nile virus by plaque formation. | seven strains of west nile virus isolated in nigeria were investigated for their ability to form plaques in monkey kidney cell monolayers. five strains antigenically related to one another produced plaques of about the same size 3 to 4 days after the addition of the overlay medium. the two other strains closely related to each other produced no plaques. their inability to produce plaques was regarded as a significant characteristic of the intratypic group to which the two strains belong. | 1975 | 1995 |
| 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 ... | 1977 | 17279 |
| cross reactions among flaviviruses in macrophage migration inhibition assay. | adult swiss albino mice were immunized intravenously with flaviviviruses. cellular immune response was studied by macrophage migration inhibition assay. migration of cells from sensitized mice was significantly inhibited in the presence of homologous virus or antigen. migration inhibition was also significant with serologically related viruses, thus establishing cross reaction in cellular immune response. | 1978 | 29477 |
| detection of sindbis and west nile viruses in the blood of living birds by indirect haemagglutination. | | 1978 | 30270 |
| quantitative and rapid assays of togaviruses by immunofluorescence. | for the quantitative assay of selected togaviruses, suspensions of bhk cells were inoculated with virus and grown in spinner cultures. at intervals, dependent on the growth characteristics of the viruses, about 10(3) cells were centrifuged on to microscope slides and then stained with fluorescent antibody. for rapid demonstration (2--3 hr) of specific viral antigens, virus was bound in successive dilutions onto microscope slides and stained. binding of specific anti-virus antibodies in both meth ... | 1979 | 40420 |
| antigenic relationships among nigerian strains of west nile virus by complement fixation and agar gel precipitation techniques. | using two serological techniques, eight nigerian west nile virus isolates were investigated to determine antigenic relationships among them, and to find out if these virus isolates were related to west nile virus strains from the different zoogeographic areas of the world. one virus differed significantly from the seven other strains and was later found to be a strain of usutu virus. the remaining strains were differentiated into two serological intratypic groups depending on their cross reactio ... | 1976 | 60810 |
| interspecies interactions of arboviruses. i. competition phenomenon in mixed populations of japanese encephalitis and west nile viruses. | two phenomena, competition and independent reproduction, were observed on co-cultivation of japanese encephalitis (je) and west nile (wn) viruses in permissive systems. competition occurred in populations propagated in mouse brains and led to elimination of je virus. only clones of wn virus were isolated from these populations at the 1st-3rd passage level. no competition was observed in mixed infection of primary syrian hamster kidney (shk) cell culturess the population had the combined immunolo ... | 1976 | 61719 |
| interspecies interactions of arboviruses. ii. participation of the genomes of two flaviviruses, west nile and japanese encephalitis, in formation of a virus clone with dual antigenic determinants. | a peculiar clone, 41/wn+je+, possessing antigenic determinants of a flaviviruses, west nile (wn) and japanese encphalitis (je), is described. the antigenic duality of this clone exceeded the cross reactions between wn and je viruses; either antiserum neutralized 104--105 pfu/ml of the virus. the property of antigenic duality was inherited in over 340 virus generations and retained upon propagation in selective cell systems and after recloning. the progeny of infectious rna consisted of 3 types o ... | 1977 | 66864 |
| host selection patterns of some pakistan mosquitoes. | the host selection patterns of 18 species of pakistan mosquitoes are described, emphasizing the presumed malaria vectors, anopheles culicifacies, an. fluviatilis, and an. stephensi, and the probable vectors of west nile virus, culex pipiens fatigans and cx. tritaeniorhynchus. all species tested, with the exception of cx, p. fatigans, were considered to be essentially zoophilic. few human feeds were recorded for an. annularis (0.7%), an. culicifacies (0.5%), an. fluviatilis (1.1%), an. nigerrimus ... | 1979 | 110157 |
| the enhancing effect of copper, nickel, and cobalt ions on plaque formation by semliki forest virus (sfv) in chicken embryo fibroblasts. | in cultured chicken embryo fibroblasts treated with copper-(copper cation 10-minus 3.5-10-minus 5 m), nickel and cobalt salts an enhancement of the plating efficiency of semliki forest virus could be observed. this augmented plaque formation was most probably due to a higher adsorption rate of virions to the cell surface under the influence of the transition metal ions. the plating efficiency of west nile virus in chicken-embryo fibroblasts and, to a lesser degree, of poliovius type 1 and 2 in k ... | 1975 | 167680 |
| the susceptibility of isolated guts from various species of mosquito to some arboviruses. | isolated guts cultured in vitro from aedes aeaegypti and ae. togoi were more susceptible to infection by sin, sf, chik and wn viruses than tissue similarly cultured from anopheles gambiae and an. stephensi. langat tp 64, a tick-borne virus, failed to infect any of the cultured mosquito tissues. | 1976 | 178280 |
| increase in lipid fluidity of cellular membranes induced by adsorption of rna and dna virions. | changes in the dynamic behavior of membrane lipids of mammalian cells induced by adsorption of animal viruses were quantitatively monitored by fluorescence polarization analysis with the aid of the fluorescent probe 1,6-diphenyl 1,3,5-hexatriene embedded in the surface membrane lipid core of intact cells. adsorption of encephalomyocarditis, west nile, and polyoma viruses to hamster (baby hamster kidney) and mouse (3t3) cells is accompanied by a rapid and significant increase in the degree of flu ... | 1977 | 194057 |
| studies on the occurrence and distribution of hi antibodies against some arboviruses in the serum of domestic mammals in puglia. | the virological and serological studies previously carried out on arboviruses in italy are reviewed. the presence of antibodies to 11 arboviruses was investigated in the serum of various domestic animals (100 horses, 107 pigs, 102 sheep, 205 goats, 100 cattle and 200 dogs) from some areas of puglia. the techniques are described. the results, given in tables and discussed in detail, support the hypothesis that in this region also there are arboviruses circulating, particularly those of group b. | 1977 | 201546 |
| arboviruses in birds captured in slovakia. | virus neutralizing (vn) antibodies against sindbis, tick-borne encephalitis (tbe), west nile (wn), tahyna and calovo viruses were found in birds captured in slovakia. in parallel, sindbis, tbe and wn viruses were isolated from the blood, brain and liver of migrating birds. | 1977 | 203628 |
| inhibition of adsorption of west-nile and herpes simplex viruses by procaine. | the effect of the local anaesthetic drug procaine on the adsorption of two enveloped viruses was studied. physiological concentrations of the drug (7 x 10(-3)--7 x 10(-2) m) strongly inhibited the adsorption of both west-nile and herpes viruses as determined by plaque assay and the infective center assay. | 1978 | 204270 |
| picorna- and togavirus infection of cells detected by gas chromatography. | viral infection of cells causes chemical and metabolic changes, which can be detected by gas chromatography (gc) of ether extracts of supernatant fluids and cell homogenates before any significant damage to the cells is observable microscopically. the characteristic and specific gc patterns obtained from bhk-21 and vero cell cultures infected with encephalomyocarditis, polio, echoviruses, and a togavirus make it possible to distinguish between these infecting viruses. the appearance of 1 or 2 co ... | 1977 | 204744 |
| [interferonogenic activity of gossypol, a low-molecular substance]. | the interferonogenic activity of gossipol, a low molecular substance of polyphenolic nature was shown in the cell cultures of chick embryos and organisms of mice. pronounced prophylactic efficiency of the drug in mice with experimental infection caused by the west nile virus was found. definite parallelism between the intensity of interferonogenesis and the protection level from the virus affection due to the use of gossipol in mice was noted. difference between gossipol and other known low mole ... | 1978 | 206198 |
| use of duck embryo cell cultures for the study of arbovirus reproduction. | duck embryo cell (dec) cultures were used for the study of arbovirus reproduction. high sensitivity of dec cultures to japanese encephalitis, west nile, tyuleniy, sakhalin and baku viruses was established. dec cultures are recommended for investigation of arbovirus reproduction. | 1975 | 241248 |
| an epidemiologic and serologic study of arboviruses in lake rudolf basin. | an epidemiologic and serologic study of arboviruses was done in 1972 in the basin of lake rudolf. the main object of this study was to demarcate the southern limit of the yellow fever epidemic which occurred from 1959 to 1962 in southern sudan and ethiopia. other purposes were to contribute to the inventory of arboviruses and their distribution in this region. the ethnic groups were studied: the nyangatom and the dassanetch in ethiopia and the turkana in northern kenya. the results of tests on s ... | 1975 | 242102 |
| affinity chromatographic analysis of murine interferons induced by viruses and by t and b cell stimulants. | murine interferons induced by viruses and by non-viral substances such as lectins, tilorone, lipopolysaccharide and brucella have been analysed by affinity chromatography on a column of sepharose coupled to antiviral interferon antibodies. the results reported here suggest that virus and b-cell stimulants induced interferons which are antigenically related and that t cell-dependent mitogens induce and "interferon like" molecule which appears to be antigenically and physiocochemically different. | 1977 | 301376 |
| evaluation of immunofluorescence and immunoperoxidase methods for antibody determination against chikungunya, west nile and yellow fever viruses. | | 1979 | 391161 |
| 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 ... | 1979 | 447128 |
| in vitro translation of 42 s virus-specific rna from cells infected with the flavivirus west nile virus. | | 1979 | 462816 |
| 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 ... | 1979 | 489960 |
| [change in the nature of the persistence of alpha- and flaviviruses in the body of balb/c strain mice with a mixed infection with leukovirus]. | the features of pathogenesis of infection caused in adult balb/c mice intraperitoneally infected with sindbis virus, virulent or attenuated strains of west nile (wn) virus, individually or in combination with rauscher leukemia virus (rlv) were studied. the influence of the latter on the course of togavirus infections was characterized by 3 features: (a) different effects on the visceral and neural phases of the pathogenesis (increased period of viremia and virus reproduction in the viscera did n ... | 1979 | 506204 |
| [modeling of chronic togavirus infection in an aedes aegypti mosquito cell culture at different temperatures]. | | 1979 | 514216 |
| infections in sentinel pigeons by sindbis and west nile viruses in south africa, with observations on culex (culex) univittatus (diptera: culicidae) attracted to these birds. | | 1979 | 537007 |
| 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 ... | 1979 | 503230 |
| 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, ... | 1979 | 479844 |
| studies on virus-specific nucleic acids synthesized in vertebrate and mosquito cells infected with flaviviruses. | | 1978 | 568848 |
| human arthropod-borne virus infections in nigeria. serological and virological investigations and shaki, oyo state. | during the early dry season of 1972, an arbovirus surveillance was carried out is shaki. on hundred and twenty human blood samples and 304 sera were processed for virus isolation and serology respectively. a high prevalence of antibodies to 8 arbovirus antigens was found in the community. percentage of positive sera was as follows: chikungunya (24%) sindbis (19%), yellow fever (55%), dengue (54%), west nile (58%) and wesselsbron (67%). human infections by ilesha virus (35%) and ingwavuma (15%) ... | 1978 | 570581 |
| epidemic outbreak caused by west nile virus in the crew of a romanian cargo ship passing the suez canal and the red sea on route to yokohama. | | 1977 | 602018 |
| [mixed sero-epidemiologic study of arbovirus-arenavirus in the small mammals of tunisia]. | blood samples of 156 small mammals caught in tunisia in 1976 and 1977 were examined for the presence of antibodies to some arboviruses and arena-viruses. haemagglutination-inhibiting antibodies against west nile virus were detected in 19.8 0/0 of examined sera, mainly from mus sp., rattus rattus, eliomys tunetae in the northern part of the country and from ctenodactylus gundi and pipistrellus kuhli in the south. in addition, antibodies against uukuniemi and bhanja were found in 3.2 0/0 and 4.5 0 ... | 1977 | 615674 |
| acute anterior myelitis complicating west nile fever. | a healthy young man developed acute anterior myelitis resembling the "polio syndrome." he had visited an area (the gulf of suez) in which west nile fever is endemic prior to his illness. the course of his febrile illness, the spinal fluid findings, and complement fixation antibody titers established the diagnosis of west nile fever. meningoencephalitis is a serious, and previously the only known, complication of this usually benign febrile illness. this is the first report, to our knowledge, of ... | 1979 | 435138 |
| isolations of west nile virus from man in nigeria. | | 1978 | 635967 |
| production of antibody in induced granulomas. | a method of producing antibodies in artificially induced granulomas with various microbial antigens is examined. | 1976 | 789397 |
| in vivo demyelination induced by intraneural injection of anti-galactocerebroside serum: a morphologic study. | intraneural injection of rabbit anti-galactocerebroside (anti-gc) serum produced focaldemyelinative lesions in rat sciatic nerves. recipient rats developed a sensory motordeficit of the toes and feet on the side injected with anti-gc serum. schwann cellabnormalities in recipient nerves were apparent by 20 minutes, followed by myelinsplitting and vesiculation over the next 8 hours. macrophages first appeared in moder-ate numbers by 15 hours, and degraded myelin was completely phagocvtized by 5 da ... | 1979 | 434114 |
| hemorrhagic fevers, with special reference to recent outbreaks in southern africa. | in considering the diagnosis of a patient admitted to the johannesburg hospital, suffering from an illness characterized by high fever and complicated by a hemorrhagic state from which he died, a list of possible causes of his illness was drawn up. this list included the arthropodborne viral infections prevalent in southern africa, namely, chikungunya fever, sindbis fever, west nile fever, yellow fever, and rift valley fever; viral infections associated with rodents, such as lassa fever; the vir ... | 1979 | 399369 |
| application of single-radial-haemolysis test for the detection of antibodies to togaviruses. | the newly developed single-radial-haemolysis technique was employed in this study for screening of sera for detection of antibodies to three nigerian togaviruses. this technique was compared with the standard haemagglutination-inhibition method. a close correlation between the two techniques was observed. | 1979 | 389203 |
| purification of togavirus haemagglutinins by chromatography on controlled pore glass. | purified preparations of haemagglutinins from sindbis, west nile and tick-borne encephalitis (tbe) viruses could be obtained from infected mouse brains by alkaline extraction, precipitation with protamine and chromatography on polyethylene glycol-coated controlled pore glass with 242 a pore diameter. | 1975 | 241241 |
| [dynamics of accumulation of infectious west nile virus and viral antigens in experimental infection of mice]. | the appearance of the hemagglutinating (ha), complement-fixing (cf) and soluble (s) antigens and infectious virus in the blood and brain of suckling mice inoculated with various doses of west nile virus was studied. the infectious virus was isolated from the blood and brains of mice as early as 24 hours after inoculation. its titres increased in parallel in the brain and blood reaching maximum levels by the end of infection. the ha antigen was detected only in the brain at 2-3 days after inocula ... | 1977 | 898895 |
| reactions of egyptian human and rodent sera to langat virus antigens. | | 1977 | 198509 |
| comparative biological studies on indian strains of west nile virus isolated from different sources. | | 1977 | 924558 |
| serologic examination of birds from the area of southern moravia for the presence of antibodies against arboviruses of the groups alfa, flavo, bunyamwera supergroup, and the virus yaba 1-lednice 110. i. domestic fowls. | 196 geese, 141 ducks, and 100 hens from 9 localities of the south moravian region (district of breclav) were examined by means of the haemagglutination-inhibition test (hit) for the presence of antibodies against 12 arbovirus antigens of the groups alfavirus (western equine encephalitis (wee), eastern equine encephalitis (eee), semliki, sindbis, chikungunya, o'nyong-nyong), flavovirus (tick-borne encephalitis (tbe), dengue and west nile virus (wn), bunyamwera supergroup (tahna and beta calovo), ... | 1975 | 175616 |
| infection of an aedes aegypti cell line with infectious arbovirus-antibody complexes. | aedes aegypti cells exposed to infectious complexes of wn or yf virus and homologous antiserum produced lower yields of virus over a 10-day observation period than were produced by aedes aegypti cells treated with a comparable dose of virus mixed with non-immune serum. when ae. aegypti cells were infected with wn virus mixed with mve, nta, den-2 or yf antisera the virus yield over 10 days was lower than in cell cultures infected at similar titres with mixtures of wn virus with non-immune serum. ... | 1976 | 982518 |
| laboratory studies on the vector capability of aedes (neomelaniconion) unidentatus mcintosh and aedes (aedimorphus/ dentatus (theobald) with west nile and sindbis viruses. | laboratory tests were made with aedes (neomelaniconion) unidentatus mcintosh and aedes (aedimorphus) dentatus (theobald) collected from the highveld region of the transvaal, south africa, to determine their ability of transmit west nile and sindbis viruses. viraemic hamsters or a viraemic chick were exposed to the mosquitoes as infective meals. infection of mosquitoes was determined by testing mosquitoes individually for the presence of virus 10-26 days later. transmission of virus, attempted be ... | 1976 | 1019752 |
| infection of the mosquito aedes aegypti with infectious west nile virus-antibody complexes. | aedes aegypti fed through chick skin membranes on west nile virus-homologous antiserum mixtures shown by an anti-globulin neutralization test to be highly infectious complexes (in terms of plaque formation in tissue culture) failed to become infected. control mosquitoes fed on west nile virus--normal rabbit serum mixtures containing similar or smaller amounts of infectious virus were shown to become infected. mosquitoes ingesting suspensions of west nile virus previously incubated with murray va ... | 1975 | 1080913 |
| assay of togavirus haemagglutination-inhibition antibodies by the micro method: loss of information and its rectification. | haemagglutination inhibition (hi) activity was assayed by the micro and macro methods in immune sera prepared against four togaviruses. hi titres were always 4 to 8 times lower by the micro method, and coincided with 4 to 8 times lower haemagglutinin titres in micro method assays. because of this phenomenon, positive sera with hi macro method titres lower than 1: 80 will be false negative for hi by the micro method when tests begin at a 1: 10 serum dilution. this was confirmed for a number of hu ... | 1976 | 1088357 |
| prevalence of antibodies to arboviruses in egypt. results of a serologic survey among 1,113 university students. | | 1975 | 173201 |
| an immunopathologic component in experimental togavirus encephalitis. | the effects of immune manipulation upon survival and histopathology in two experimental group b togavirus encephalitides were studied in inbred mice. the median survival time 8 days after intracerebral injection of langat virus increased to 10 days with an immunosuppressive course of cyclophosphamide, with concomitant reduction in the inflammatory response. adoptive immunization with immune lymphoid cells or serum also tended to prolong langat virus survival while increasing inflammation. surviv ... | 1975 | 171349 |
| structure and chemical-physical characteristics of lactate dehydrogenase-elevating virus and its rna. | lactate dehydrogenase-elevating virus (ldv) was purified from culture fluid of infected primary cultures of various mouse tissues (peritoneal macrophage, bone marrow, spleen, and embryo) and from plasma of infected mice. electron microscopy of negatively stained virus and positively stained sections of ldv revealed spherical particles of uniform size with a diameter of about 55 nm, containing an electron-dense core with a diameter of about 30 nm. during sample preparation the envelope had a tend ... | 1975 | 1171266 |
| interferon induction and action in transformed poikilothermic cells. | the production and effect of interferon in the virus-transformed cell line tgk1, originating from kidney cells of testudo gracea were studied and compared to those in the primary cell culture. west nile virus and newcastle disease virus were used as inducers. interferon production in tgk1 cells began 6 hr later than in the primary cell culture and reached the maximum 64 iu, 18 hr after virus inoculation. in the primary culture, interferon production increased till the 48th hr reaching a fourfold ... | 1975 | 168742 |
| dehydroepiandrosterone protects mice inoculated with west nile virus and exposed to cold stress. | the protective effect of pretreatment with dehydroepiandrosterone (dhea) on stress-enhanced viral encephalitis was studied in mice exposed to cold following inoculation with west nile virus (wnv). exposure of wnv-inoculated mice to cold water (1 +/- 0.5 degrees c, 5 minutes/day for 8 days) resulted in a mortality rate of 83% as compared to 50% in nonstressed mice (p < 0.05). the effect of cold stress was more pronounced when mice were inoculated with wn-25, a noninvasive neurovirulent variant of ... | 1992 | 1287129 |
| "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 ... | 1976 | 130853 |
| effect of passage history on dengue-2 virus replication in subpopulations of human leukocytes. | three passage levels of dengue-2 virus strain pr-159, obtained during the course of deriving the attenuated s-1 vaccine, were tested for their ability to replicate in subpopulations of human peripheral blood leukocytes: (i) 6th primary african green monkey kidney (pgmk) cell passage (parent virus); (ii) 19th pgmk cell passage of a small-plaque-forming clone derived from the parent virus (s-1 pgmk virus); and (iii) virus derived by four additional passages of the s-1 pgmk virus in diploid fetal r ... | 1979 | 121109 |
| kinetic haemagglutination inhibition technique as a means of detecting antigenic variations among strains of nigerian flaviviruses. | seven isolates of west nile virus and an additional isolate tentatively identified at the outset as west nile virus, were compared by casals' modified haemagglutination inhibition technique. two of the isolates were nearly identical; a second set of five isolates cross-reacted among themselves within a wide range and differed from the first two; the last isolate was significantly different from the others. | 1978 | 77150 |
| comparative serological studies on indian strains of west nile virus isolated from different sources. | | 1977 | 72730 |
| the prevalence of arboviral, rickettsial, and hantaan-like viral antibody among schoolchildren in the nile river delta of egypt. | a serosurvey was conducted during october and november 1989 to estimate the prevalence of selected arboviral, rickettsial, and hantaan viral antibody among a sample of schoolchildren from 4 villages in the bilbeis area of the nile river delta, egypt. blood specimens were obtained from subjects aged 8 to 14 years. enzyme immunoassay testing of the sera indicated that the prevalence of antibody was 9% (21/223) for sicilian sandfly fever, 4% (8/223) for rift valley fever, 3% (15/437) for west nile ... | 1992 | 1363163 |
| interaction of mouse peritoneal macrophages with different arboviruses in vitro [proceedings]. | | 1976 | 66026 |
| replication of flaviviruses in mouse organ cultures [proceedings]. | | 1976 | 66024 |
| [determination of arbovirus group affiliation in the indirect hemagglutination reaction]. | a dry polyvalent erythrocyte immunoglobulin diagnostic preparation for arboviruses of group b may be prepared to be used in the indirect hemagglutination test. the preparation detects antigens of arboviruses of this group in the tissue culture fluid and in suckling mouse brain tissue treated with sucrose-acetone. the test with group b arbovirus antigens is inhibited specifically by the homologous polyvalent immune gamma globulin. inhibition of hemagglutination by species-specific immune globulin ... | 1975 | 54999 |
| viral neuroinvasion and encephalitis induced by lipopolysaccharide and its mediators. | the present study was designed to test the effect of bacterial endotoxin on penetration of viruses into the central nervous system (cns). as a model we used two neurovirulent viruses that lack neuroinvasive capacity: west nile virus-25 (wn-25) and neuroadapted sindbis virus (svn). administration of lipopolysaccharide (lps, 100 micrograms/mouse) to cd-1 mice, followed by wn-25 inoculation resulted in 83% encephalitis and death, compared with less than 5% in controls. the results in svn-inoculated ... | 1992 | 1512538 |
| detection of west nile complement-fixing antigen in aedes albopictus cell cultures. | | 1975 | 52295 |
| monoclonal antibodies to kunjin and kokobera viruses. | five monoclonal antibodies (moab) were produced to the envelope (e) protein of kunjin (kun) virus. three of these were specific for the kun/west nile complex, and two reacted with epitopes that were common to the flavivirus family. these moab defined at least four distinct epitopes on the e protein of kun virus. eight moab were also produced to unidentified proteins of kokobera (kok) virus. seven were specific for kok, while the remaining antibody cross-reacted with stratford virus and an unregi ... | 1991 | 1651286 |
| protection by dehydroepiandrosterone in mice infected with viral encephalitis. | dehydroepiandrosterone (dhea) has a significant protective effect in mice infected with west nile virus (wnv), sindbis virus neurovirulent (svni) and semliki forest virus (sfv). mice injected subcutaneously (sc) with a single injection of dhea (1 g/kg) on the same day or one day pre or post infection with wnv resulted in 40-50% mortality as compared to 100% in control injected mice (p less than 0.05). the drug was effective following a single sc injection or serial intraperitoneal (ip) injection ... | 1991 | 1659799 |
| a second group of hepatitis c viruses. | cdna clone 11-7 was isolated by immunoscreening a cdna library that was prepared from a pooled plasma of non-a non-b hepatitis (nanbh) patients using expression vector lambda gt11. this cdna corresponds to known nucleotide positions 3983-4745 of the genome of hepatitis c virus (hcv). this clone was used as a probe for screening the hcv-related cdnas in a cdna library similarly prepared by using lambda gt10. as a result, six more cdna clones were isolated and analyzed for their nucleotide sequenc ... | 1991 | 1663293 |
| biological characteristic of nigerian strains of west nile virus in mice and cell cultures. | the biological characteristic in mice and cell cultures of 7 strains of west nile (wn) virus isolated in nigeria were studied. the pattern of virus development in most organs of mice infected with two of the seven strains tested was identical, while it varied with the remaining five strains. all 7 strains of wn virus multiplied with a cytopathic effect (cpe) in the four cell cultures examined. | 1977 | 17286 |
| different pathogenicity of encephalitic togaviruses in organotypic cultures of spinal cord slices. | the pathogenicity of two encephalitic togaviruses, sindbis virus (sv), an alphavirus, and west nile virus (wnv), a flavivirus, was studied in organotypic cultures of fetal mouse spinal cord slices grown in roller tubes. after about 3 weeks in vitro, during which time the cultures became abundantly myelinated, they were infected either by 5 x 10(5) pfu sv or by 5 x 10(6) pfu wnv per culture. the viruses caused different patterns of cytopathogenicity: sv induced severe cytotoxicity in all glia cel ... | 1990 | 1691307 |
| epidemiologic study of arboviruses in the arba-minch district of ethiopia. | a yellow fever outbreak occurred in 1966 in arba-minch district, east of abaya lake, in ethiopia. the present study was undertaken to assess the southern limits of that epidemic and to contribute to the inventory of arboviruses and potential vectors in that area. in the highlands 90 sera were collected, in the lowlands 140. with regard to group b the sera reacted only with yellow fever, wesselsbron and spondweni antigens. in the highlands 17.8%, in the lowlands 22.2%, were positive for group b. ... | 1976 | 13526 |
| alterations in the developmental patterns of enzymes in chicken embryos infected with west nile virus. | | 1976 | 11747 |
| some properties of togavirus hemagglutinin studied with the aid of kaolin-adsorbed virus. | acidification (at ph 5.75) of semliki forest virus and west nile virus suspensions completely eliminated their hemagglutinating activity within several minutes, but did not affect their infectivity or change their ability to absorb homologous hemagglutination-inhibition antibodies. in order to assay antibody absorption it was necessary to remove all of the immune complex from the reaction mixture, because the immune complex inhibited additional hemagglutinin. removal of the immune complex can be ... | 1976 | 9052 |
| comparison of vector competence for west nile virus of colonized populations of culex tritaeniorhynchus from southern asia and the far east. | seven colonized stocks of cx. tritaeniorhynchus from different geographic areas of southern asia and the far east were assayed for susceptibility to wn virus infection by membrane feeding and by intrathoracic inoculation. infected females also were tested for their ability to transmit virus to baby mice. no geographic pattern of differential susceptibility to wn virus infection was apparent from the experiments; however, the per os id50 of one strain from khulna, bangladesh was over 10-fold grea ... | 1979 | 538499 |
| role of extracellular virus on the maintenance of the persistent infection induced in aedes albopictus (mosquito) cells by sindbis virus. | sindbis virus infection of cultured mosquito cells was found to have no effect on the growth of these cells; instead, a persistent infection of the culture followed an initial acute phase of rapid virus synthesis. nearly all of the cells in the acute stage of infection were found to actively release virus in an infectious-center assay and to contain significant amounts of virus antigen as determined by immunofluorescence. cells in the persistent phase of infection released few virions into the m ... | 1977 | 561193 |
| an unusually high divalent cation requirement for attachment of west nile virus to primary chick embryo cells. | | 1978 | 622400 |
| the carboxy-terminal part of the ns 3 protein of the west nile flavivirus can be isolated as a soluble protein after proteolytic cleavage and represents an rna-stimulated ntpase. | recently it has been reported that a membrane fraction can be isolated from west nile virus-infected bhk cells which contains the viral nonstructural (ns) proteins as major constituents (wengler et al., 1990). in this report we show that treatment of these membranes with subtilisin releases the carboxy-terminal segment of the ns 3 protein as a soluble protein of about 50 kda apparent molecular weight. this molecule, which is called the p50-s protein, can be purified by standard chromatographic p ... | 1991 | 1716026 |
| in vitro t-cell proliferative response to the flavivirus, west nile. | west nile virus (wnv)-specific murine t-cell proliferation in vitro was investigated in terms of conditions that optimize antigen-specific responses and reduce background proliferation. the responder populations consisted of splenocytes from wnv-primed mice enriched for l3t4+ t cells. ia+ antigen-presenting cells (apc) were derived from splenocytes of wnv-primed or naive mice. antigen was a lysate prepared from wnv-infected vero cells at 12 h postinfection. strong virus-specific proliferative re ... | 1991 | 1722099 |
| [prevalence of antibodies to west nile virus in youngsters from 5 to 20 years old in madagascar]. | in 1990 a serological investigation among 3,177 children (5 to 20 years old) sera has been conducted by the pasteur institute of madagascar in several areas of madagascar, in order to evaluate the prevalence of west nile virus antibodies. 29.9% out of human sera tested by elisa for west nile igg antibodies are positive, that shows a rather high level of west nile virus circulation in madagascar. prevalence is increasing with age but no significant difference has been registered among prevalence ... | 1991 | 1764750 |
| [clinical and epidemiologic significance of arboviruses in central europe]. | | 1976 | 794666 |
| [west nile arbovirus antibodies with hemagglutination inhibition (hi) in residents of southeast anatolia]. | 937 sera collected from different persons in southeast anatolia were studied for antibodies against west nile - virus by hi test. 763 out of 937 sera were from the research area, 42 from the neighboring districts and 21 from soldiers recently come to the research area, the features of the remaining 111 sera, except the ages of 4 could not be recorded. in the sera from the research area the west nile antibodies were positive in 41.80%. the positive ratios were 40.49% in diyarbakir, 47.83% in mard ... | 1977 | 857119 |
| 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 ... | 1977 | 870434 |
| west nile virus infection of adult mice by oral route. | adult swiss albino mice were fed orally with suspensions of a strain of west nile virus isolated in nigeria. most of these mice became sick and died 7 days post feeding and virus was recovered from organs of such infected mice. histological lesions were observed in some tissues and antibody to the strain of west nile virus developed in mice that survived infection. | 1977 | 889447 |
| epidemiological investigations on arbovirus infections at igbo-ora, nigeria. | a study of arbovirus infections occurring in igbo-ora community was carried out between may and october 1975. haemagglutination inhibition test performed on seventy-eight human sera showed a high prevalence of antibodies against all the six arboviruses used. percentage of positive sera were as follows: chikungunya, (28%); yellow fever (36%); dengue type 1 (67%); dengue type 2 (45%). prevalence of hi antibodies to west nile and wesselsbron viruses were 44% and 59% respectively. virus isolation st ... | 1977 | 906078 |
| in vitro homotypic and heterotypic interference by defective interfering particles of west nile virus. | defective interfering (di) particles of the flavivirus west nile (wn) were generated after as few as two high multiplicity serial passages in vero and llc-mk2 cells. six cell lines (vero, llc-mk2, l929, hela, bhk-21 and sw13) were used to assay interference by di particles in a yield reduction assay. interference was found to vary depending on the cell type used. the highest levels of interference were obtained in llc-mk2 cells, whereas no detectable effect was observed in bhk-21 and sw13 cells. ... | 1991 | 1940867 |
| the ornithodoros (alectorobius) capensis group (acarina: ixodoidea: argasidae) of the palearctic and oriental regions. o. (a.) maritimus: identity, marine bird hosts, virus infections, and distribution in western europe and northwestern africa. | in 1967, vermeil and marguet described ornithodoros coniceps maritimus from larvae reared from larvae taken from marine birds on dumet island (atlantic ocean), basse bretagne, france. we collected o. (a.) coniceps canestrini, 1890, from the type locality (venice, italy) and determined that the taxons coniceps and maritimus each require full species status. we selected a lectotype and paralectotypes for the taxon maritimus from the original dumet island material. the larva of maritimus is redescr ... | 1976 | 978368 |
| [fibrin removal from mouse immune ascitic fluids to arbovirus using beta-propiolactone]. | a modification of acid precipitation of fibrin in immune ascitic fluids (iaf) employing beta-propiolactone has been developed. the procedure removes fibrin completely without affecting the titres of specific antibody. this modification is not inferior to previously described methods for fibrin removal from iaf and has a number of advantages. in addition to removing fibrin from iaf, beta-propiolactone prevents possible virus contamination of iaf and sterilizes the preparation additionally. | 1975 | 1092073 |
| virus infections in infant mice causing persistent impairment of turnover of brain catecholamines. | newborn mice were inoculated with attenuated coxsackie type b4 virus. three-to-4-day old mice were infected with yellow fever virus vaccine. a number of mice survived the acute infections. some of these demonstrated residual neurological symptoms, some showed recovery from symptoms while others survived the infection without revealing symptoms of disease. determinations of dopamine, noradrenaline, 5-hydroxytryptamine, homovanillic acid and 5-hydroxyindoleacetic acid in the inoculated brains indi ... | 1975 | 1159458 |
| [use of monoclonal antibodies for the antigenic analysis of west nile viral strains isolated in madagascar. contribution to the understanding of the epidemiological cycle]. | the antigenic relationship of 53 madagascar west nile isolates to each other and to the two prototype viruses (eg 101 and g 2266) was assessed using monoclonal antibodies. in madagascar exist 5 antigenic groups: 4 which are much closer to the egyptian strain eg 101 than to the indian, and antigenically distinct from south african h 442 strain. one other is closely related to indian strain g 2266. antigenic variations are observed in every periods of transmission cycle. some differences between s ... | 1990 | 2078079 |
| west nile complement fixing antibodies in nigerian domestic animals and humans. | a survey for west nile complement fixing (cf) antibody was carried out in humans and domestic animals in nigeria. human sera were obtained from two communities namely ibadan and ogbomoso but animal sera were collected from ibadan and maiduguri. the overall cf antibody to west nile virus in the two localities surveyed was 65%. of 170 persons tested, 53% and 75% were positive in ibadan and ogbomoso respectively. antibody prevalence increased with age in both communities. tests for antibody against ... | 1990 | 2100749 |
| 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 ... | 1976 | 1270142 |
| description of a procedure which allows isolation of viral nonstructural proteins from bhk vertebrate cells infected with the west nile flavivirus in a state which allows their direct chemical characterization. | we have developed a procedure which allows isolation of virus-coded nonstructural (ns) proteins from bhk cells infected with the west nile (wn) flavivirus in a state of purity which allows their chemical characterization. a crude membrane fraction proved to be a suitable starting material. incubation of crude membranes in buffer containing 1.2 m guanidine hydrochloride (gh) allows isolation of weakly washed membranes. incubation of weakly washed membranes in the presence of either 5 m gh or 8 m ... | 1990 | 2142559 |
| the influence of cold or isolation stress on resistance of mice to west nile virus encephalitis. | the effect of cold or isolation stress on mortality rate and brain virus level were investigated in mice infected with west nile virus (wnv). exposure of mice for 5 min/day to cold water (1 +/- 0.5 degrees c) for 8-10 days resulted in 92% mortality as compared to 47% in control mice (p less than 0.001). mice housed in individual cages (isolation stress) were also more susceptible to wn viral infection, as shown by increased mortality rate reaching 85% as compared to 50% in mice housed 6 per cage ... | 1990 | 2155814 |
| a survey for haemagglutination-inhibiting antibody to west nile virus in human and animal sera in nigeria. | a survey for west nile virus (wnv) haemagglutination-inhibition (hi) antibody was carried out in humans and domestic animals. human sera were collected from ibadan, while the animal sera were collected from both ibadan and maiduguri. out of 304 human sera tested, 123 were positive (40%). there was a higher prevalence of hi antibody in adults than children. sex distribution of positive sera showed that 37% of males and 43% of females had wnv hi antibody. there was no significant difference in the ... | 1990 | 2323182 |
| [serological surveillance of west nile virus infection in a village of the central highlands in madagascar]. | a serological survey on the frequency of west nile virus antibodies has been carried out in a village near antananarivo. igg antibodies were searched for by enzyme-linked immunosorbent assay on 460 sera collected in december 1988 and on 494 sera collected in july 1989. the prevalence of west nile virus antibodies varied from 13.4% to 21.8% between the beginning and the end of the rainy season. seroconversion was observed in 14.7% of 354 paired serum samples collected in december and july which h ... | 1990 | 2369170 |
| antigenic comparison of envelope protein e between japanese encephalitis virus and some other flaviviruses using monoclonal antibodies. | the antigenic relationships between japanese encephalitis (je) virus and several other flaviviruses have been investigated using anti-je virus monoclonal antibodies (mabs). seventeen mabs directed against envelope protein e of je virus were characterized and divided into eight mab groups based on reactivity patterns in haemagglutination inhibition test, neutralization (n) test, elisa and competitive binding assay with je virus. the results suggest the existence of at least eight epitopes on the ... | 1986 | 2432163 |
| microcarriers as a culturing system of insect cells and insect viruses. | there is an increasing interest in culturing of insect cells, which are host for arthropod-born (arbo) viruses. the potential applications of arbo viruses are in the following two main fields: 1. medical applications (e.g. preparation of viral vaccines and viral antigens for diagnostic purposes). 2. as bioinsecticides in pest control in horticulture, agriculture and forestry. one of the potential cell substrates for these applications is an anchorage-dependent-mosquito cell line established from ... | 1987 | 2438174 |
| 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 ... | 1992 | 1321321 |
| [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 ... | 1992 | 1321397 |
| analysis of murine major histocompatibility complex class ii-restricted t-cell responses to the flavivirus kunjin by using vaccinia virus expression. | the present paper analyzes the influence of major histocompatibility complex (mhc) class ii (ir) genes on mhc class ii-restricted t-cell responses to west nile virus (wnv) and recombinant vaccinia virus-derived kunjin virus antigens and identifies the immunodominant kunjin virus antigens. generally, mice were primed by intravenous infection with wnv or kunjin virus, and their cd4+ t cells were stimulated in vitro 14 days later with wnv or kunjin virus antigens to pulse macrophage or b-cell antig ... | 1992 | 1349926 |
| two-way cross-protection between west nile and japanese encephalitis viruses in bonnet macaques. | cross-protection between japanese encephalitis (je) and west nile (wn) viruses was tested in bonnet macaques (macaca radiata) immunized either with je virus (jev) or wn virus (wnv). jev immunized monkeys were challenged by intranasal (i.n.) route with wnv and vice versa. four control unimmunized monkeys were similarly infected either with wnv or jev. two of three control monkeys infected with wnv, developed paralysis followed by death. virus was recovered from the central nervous system (cns) of ... | 1992 | 1360756 |
| broad cross-reactivity with marked fine specificity in the cytotoxic t cell response to flaviviruses. | cytotoxic t (tc) cells were generated in mice of five h-2 haplotypes against the flaviviruses kunjin and west nile (wnv). a panel of recombinant vaccinia viruses which between them expressed cdna of the entire kunjin virus genome were used to infect targets. anti-kunjin virus responses to determinants derived from non-structural proteins, especially ns3, ns4a and ns4b, were dominant in most mouse strains; usually only one class i major histocompatibility complex (mhc) restriction element was inv ... | 1992 | 1375278 |