characterization of nigerian strains of west nile virus by plaque 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.19751995
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 ...19769052
alterations in the developmental patterns of enzymes in chicken embryos infected with west nile virus. 197611747
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. ...197613526
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
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.197717286
cross reactions among flaviviruses in macrophage migration inhibition 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.197829477
detection of sindbis and west nile viruses in the blood of living birds by indirect haemagglutination. 197830270
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 ...197940420
detection of west nile complement-fixing antigen in aedes albopictus cell cultures. 197552295
[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 ...197554999
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 ...197660810
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 ...197661719
replication of flaviviruses in mouse organ cultures [proceedings]. 197666024
interaction of mouse peritoneal macrophages with different arboviruses in vitro [proceedings]. 197666026
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 ...197766864
comparative serological studies on indian strains of west nile virus isolated from different sources. 197772730
kinetic haemagglutination inhibition technique as a means of detecting antigenic variations among strains of nigerian 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.197877150
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 ...1979110157
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 ...1979121109
"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
the enhancing effect of copper, nickel, and cobalt ions on plaque formation by semliki forest virus (sfv) in chicken embryo 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 ...1975167680
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 ...1975168742
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 ...1975171349
prevalence of antibodies to arboviruses in egypt. results of a serologic survey among 1,113 university students. 1975173201
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), ...1975175616
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.1976178280
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 ...1977194057
reactions of egyptian human and rodent sera to langat virus antigens. 1977198509
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.1977201546
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.1977203628
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.1978204270
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 ...1977204744
[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 ...1978206198
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.1975241241
use of duck embryo cell cultures for the study of arbovirus 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.1975241248
an epidemiologic and serologic study of arboviruses in lake rudolf 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 ...1975242102
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.1977301376
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.1979389203
evaluation of immunofluorescence and immunoperoxidase methods for antibody determination against chikungunya, west nile and yellow fever viruses. 1979391161
hemorrhagic fevers, with special reference to recent outbreaks in southern 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 ...1979399369
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 ...1979434114
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 ...1979435138
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
in vitro translation of 42 s virus-specific rna from cells infected with the flavivirus west nile virus. 1979462816
proteins specified by togaviruses in infected aedes albopictus (singh) mosquito cells.yields of greater than 10(7) p.f.u./ml at 28 or 37 degrees c of the alphavirus sindbis and the flavivirus kunjin were obtained in the aedes albopictus (singh) cell line, the latent periods being 4 to 6 and 10 to 12 h, respectively. despite a high background of host protein synthesis, virtually all the virus-specified proteins of the flaviviruses kunjin, dengue-2 and japanese encephalitis were labelled and resolved by slab gel electrophoresis of infected and uninfected cell proteins. in contrast, ...1979479844
zika virus infections in nigeria: virological and seroepidemiological investigations in oyo state.a study of zika virus infections was carried out in four communities in oyo state, nigeria. virus isolation studies between 1971 and 1975 yielded two virus isolations from human cases of mild febrile illness. haemagglutination-inhibition tests revealed a high prevalence of antibodies to zika and three other flaviviruses used. the percentages of positive sera were as follows: zika (31%), yellow fever (50%), west nile (46%), and wesselsbron (59%). neutralization tests showed that 40% of nigerians ...1979489960
antibody-mediated enhancement of flavivirus replication in macrophage-like cell lines.interactions between animal viruses and antiviral antisera may exceptionally result in an apparent increase in viral infectivity. halstead and coworkers demonstrated enhanced replication of dengue virus (a flavivirus, family togaviridae) in human or simian peripheral blood leucocytes carrying fc receptors at subneutralising concentrations of antidengue antibody. we have used three continuous cell lines which express macrophage markers to explore the mechanism of this phenomenon. dengue virus fai ...1979503230
[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 ...1979506204
[modeling of chronic togavirus infection in an aedes aegypti mosquito cell culture at different temperatures]. 1979514216
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. 1979537007
comparison of vector competence for west nile virus of colonized populations of culex tritaeniorhynchus from southern asia and the far 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 ...1979538499
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 ...1977561193
studies on virus-specific nucleic acids synthesized in vertebrate and mosquito cells infected with flaviviruses. 1978568848
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%) ...1978570581
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. 1977602018
[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 ...1977615674
an unusually high divalent cation requirement for attachment of west nile virus to primary chick embryo cells. 1978622400
isolations of west nile virus from man in nigeria. 1978635967
production of antibody in induced granulomas.a method of producing antibodies in artificially induced granulomas with various microbial antigens is examined.1976789397
[clinical and epidemiologic significance of arboviruses in central europe]. 1976794666
[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 ...1977857119
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
west nile virus infection of adult mice by oral 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.1977889447
[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 ...1977898895
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 ...1977906078
comparative biological studies on indian strains of west nile virus isolated from different sources. 1977924558
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 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 ...1976978368
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. ...1976982518
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 ...19761019752
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 ...19751080913
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 ...19761088357
[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.19751092073
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 ...19751159458
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 ...19751171266
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
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 ...19921287129
a stochastic analysis of three viral sequences.this paper analyzes the nucleotide sequences of three viruses: kunjin, west nile, and yellow fever. each virus has one long open reading frame of greater than 10,200 nucleotides that codes for four structural and seven nonstructural genes. the kunjin and west nile viruses are the most closely related pair, when assessed on the basis of matches between their nucleotide sequences. as would be expected, the matching is least for bases at third-position codon sites and is greatest for second-positio ...19921321321
[transfusion-associated non-a, non-b, non-c hepatitis caused by flaviviruses].hepatitis c virus was shown to be a member of the flavivirus family. tick-borne encephalitis virus and west nile virus, members of the same family occur in hungary, too. serum samples from patients suffering from transfusion associated hepatitis were tested with yellow fever virus antigens for specific igg, and igm using immunofluorescence test. eight hundred serum samples were tested. yellow fever virus related igg antibodies were found in 232 sera. in the case of 72 patients specific igm antib ...19921321397
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 ...19921349926
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 ...19921360756
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 ...19921363163
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 ...19921375278
[search for inhibitors of west nile virus among antibiotics].the activity of 24 antibiotics was studied in treatment of albino mice with experimental encephalitis caused by west nile virus. the antiviral activity of gentamicin and kanamycin was stated. the survival rate of the animals 19. contaminated with 10-100 ld50 of the west nile virus and treated parenterally with gentamicin in a dose of 80 to 400 micrograms/mouse was higher than that in the controls by 29.5 to 100 per cent and depended on the drug regimen. the efficacy of kanamycin was lower. the c ...19921456820
flavivirus induces mhc antigen on human myoblasts: a model of autoimmune myositis?infection of human embryonic myoblasts by west nile virus (wnv), a flavivirus, caused significant upregulation of class i and ii mhc expression as determined by flow cytometry. after 48 hours at a multiplicity of infection of 5 pfu/cell, a sixfold increase in mhc class i expression was induced from initially low levels of expression. in contrast, mhc class ii was induced de novo to five times the control fluorescence level. at least 70% of the cells were infected as determined using fluorescence ...19921488065
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 ...19921512538
dengue virus infection of human skin fibroblasts in vitro production of ifn-beta, il-6 and gm-csf.dengue virus is transmitted to humans by the bite of infected mosquitos. in our efforts to understand the pathogenesis of dengue virus infection, we examined whether skin fibroblasts can be infected in vitro with dengue viruses. fibroblasts could be infected with dengue viruses, yellow fever virus and west nile virus. dengue virus antigen-positive cells were detected as early as 4 h and the percentage of dengue virus antigen-positive cells reached maximum levels by 24 h after infection. high tit ...19921571018
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 ...19911651286
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 ...19911659799
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 ...19911663293
functional analysis of macrophages, b cells and splenic dendritic cells as antigen-presenting cells in west nile virus-specific murine t lymphocyte this paper, the relative efficacy of macrophages, b cells and splenic dendritic cells (sdc) in presenting west nile virus (wnv) antigens to wnv memory cd4+ t cells is examined. the results indicate that, under appropriate conditions, all these cell types can function as antigen-presenting cells (apc). listeria-induced peritoneal macrophages induced higher proliferative responses than sdc or b cells derived from naive or 14 day wnv-primed mice. the ability of listeria-induced macrophage popula ...19911680803
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 ...19901691307
west nile virions aligned along myelin lamellae in organotypic spinal cord cultures.organotypic spinal cord cultures infected with west nile virus (wnv) exhibited a remarkable arrangement of virions among lamellae of the myelin sheath. virions were first observed in neurons and only at day 4 after infection appeared within the myelin lamellae. virions were observed only in the central myelin, aligned along the interperiod lines and therefore attached to the outer side of the oligodendrocyte membrane. in spite of this peculiar location of the virions, their presence was not asso ...19901700138
computer analysis of antigenic domains and rgd-like sequences (rgwg) in the e glycoprotein of flaviviruses: an approach to vaccine development.antigenic domains and rgd-like sequences in the e glycoprotein of the flaviviruses japanese encephalitis virus, yellow fever virus, west nile virus, dengue type 4 virus, and tick-borne encephalitis virus were analyzed by computer programs that provide information on the physical properties of the polypeptides. the use of computer programs for the development of vaccines based on the synthesis of antigenic peptides is discussed. synthetic viral peptides are proposed to be used for topical applica ...19901702915
comparative analysis of west nile virus strains isolated from human and animal hosts using monoclonal antibodies and cdna restriction digest profiles.three west nile (wn) virus strains isolated in bangui, central african republic (car), from patients with hepatitis were analysed comparatively with the prototype wn virus strain and 7 wn strains previously isolated from birds (2 strains), mosquitoes (3 strains) and ticks (2 strains) in car. the comparison was based on two techniques: an epitopic analysis by indirect immunofluorescence assay using a panel of 9 monoclonal antibodies to wn virus, and an analysis of haeiii and taqi restriction dige ...19901703658
dengue virus-specific, human cd4+ cd8- cytotoxic t-cell clones: multiple patterns of virus cross-reactivity recognized by ns3-specific t-cell clones.thirteen dengue virus-specific, cytotoxic cd4+ cd8- t-cell clones were established from a donor who was infected with dengue virus type 3. these clones were examined for virus specificity and human leukocyte antigen (hla) restriction in cytotoxic assays. six patterns of virus specificities were determined. two serotype-specific clones recognized only dengue virus type 3. two dengue virus subcomplex-specific clones recognized dengue virus types 2, 3, and 4, and one subcomplex-specific clone recog ...19911705990
recognition of helper t cell epitopes in envelope (e) glycoprotein of japanese encephalitis, west nile and dengue viruses.helper t (th) cell antigenic sites were predicted from the primary amino acid sequence (approximately 500 in length) of the envelope (e) glycoprotein (gp) of japanese encephalitis (je), west nile (wn) and dengue (den) i-iv flaviviruses. prediction of th epitopes was done by analyzing the occurrence of amphipathic segments, rothbard-taylor tetra/pentamer motifs and presence of alpha helix-preferring amino acids. the simultaneous occurrence of all these parameters in segments of e gp were used as ...19911707135
preliminary analysis of murine cytotoxic t cell responses to the proteins of the flavivirus kunjin using vaccinia virus expression.a series of recombinant vaccinia viruses expressing various parts of the entire kunjin virus (kun) coding region was used to analyse the cytotoxic t (tc) cell responses to kun. cba/h mice inoculated with kun or west nile virus were shown to develop responses to kun or various vaccinia virus expression constructs in either primary cytotoxic assays, or after secondary stimulation of the tc cells in vitro with kun antigens. tc cells from cba mice showed the strongest response to target cells infect ...19911713261
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 ...19911716026
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 ...19911722099
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