| mosquito-virus relationships of american encephalitides. | | 1978 | 24407 |
| cellular localization of saint louis encephalitis virus replication. | replication of saint louis encephalitis (sle) virus was inhibited when ps cells were treated with actinomycin d, daunomycin or cordycepin during the first 9 hr after infection. autoradiography of sle virus-infected pulse labelled cells demonstrated that viral rna synthesis is localized within the nuclear area. nuclei purified from cells after 12 hr of infection contained heterogeneous 20 s to 26 s viral rna but no sle virus genome sized 43 s rna. later during infection, nuclei isolated from infe ... | 1979 | 40415 |
| [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 |
| biological and immunological studies on two substrains, c-1 and c-3, derived from the nakayama-nih strain of japanese encephalitis virus. | a comparative analysis was performed on two substrains, c-1 and c-3, derived from the nakayama-nih strain of japanese encephalitis virus. the infectivity of the two substrains was inactivated at similar rates by treatment with tween 80 and tween 20 but not by treatment with tween 60. however, hemagglutinating activity as measured at ph 6.8 of the c-3 substrain treated with tween 80 was more labile than that of the c-1 substrain treated with tween 80. also, the immunogenicity (neutralizing and he ... | 1977 | 67102 |
| antigenic characterization of flavivirus structural proteins separated by isoelectric focusing. | isoelectrofocusing of nonionic-detergent-disrupted flaviviruses separated the envelope glycoprotein of 53,000 to 58,000 daltons and the nucleocapsid protein of 14,000 daltons. the envelope protein and nucleocapsid protein were isolated at isoelectric points of pi 7.8 and 10.3, respectively. the antigenic determinants of st. louis encephalitis, japanese encephalitis, and dengue virus envelope and nucleocapsid proteins were examined by solid-phase competition radioimmunoassay. by the appropriate s ... | 1977 | 69040 |
| immune response deficiency of bsvs mice. ii. generalized deficiency to thymus-dependent antigens. | bsvs mice gave abnormally low igg responses to 5 thymus-dependent antigens as well as a weak delayed-type hypersensitivity (dth) response to sheep red blood cells. in contrast to igg, the igm antibody responses of these mice were normal to three t-independent antigens as well as to all five t-dependent antigens. the low immune responsiveness of bsvs mice was also reflected in the low levels of igg(2)a, igg(2)b and igg(3) in their normal serum. the low t-dependent immune responses may result from ... | 1979 | 89033 |
| sensitivities of neurotropic arboviruses to human interferon. | the sensitivities of selected neurotropic arboviruses (st. louis encephalitis, western equine encephaltis, and la crosse viruses) to human interferon and polyriboinosinic-polyribocytidylic acid (poly i-poly c) were determined in primary human fetal glial cell cultures. the sensitivities were measured by an end point (inhibition of virus yield). all of the viruses were sensitive to human interferon and poly i-poly c; st. louis encephalitis and western equine encephalitis viruses were inhibited at ... | 1975 | 171314 |
| arboviruses in new york state: an attempt to determine the role of arboviruses in patients with viral encephalitis and meningitis. | in a reveiw of 2,963 patients with signs of infections of the central nervous system in new york state in 1966--1977, arboviruses were found to be the confirmed or presumptive etiologic agents in 60 patients. california encephalitis (ce) virus was the most common (44 patients), followed by powassan (pow) virus (8), st. louis encephalitis virus (7), and eastern equine encephalitis (eee) virus (1). most patients (47) were children. the incidence of encephalitis was higher in patients with arboviru ... | 1979 | 222159 |
| epidemic venezuelan equine encephalitis in north america in 1971: vector studies. | a major epidemic of venezuelan equine encephalitis occurred in south texas in the summer of 1971. more than 1500 equines died of vee in texas, and 110 human cases with no deaths were reported. vector studies in south texas and northern tamaulipas revealed that the overall mosquito infection rates during the peak of the epidemic were about 1:100, one of the highest rates observed for a major epidemic. mosquito infection rates of this magnitude could easily explain the intensity of vee outbreaks i ... | 1975 | 235212 |
| arbovirus vector ecology studies in mexico during the 1972 venezuelan equine encephalitis outbreak. | virus vector studies were conducted in the states of durango, chihuahua, and tamaulipas, mexico, in june and july 1972. apparently only a low level of venzuelan equine encephalitis (vee) virus transmission to equines occured at the time of the study, and the infection was restricted to areas which had not experienced overt activity during the preceding year. the low level of infection was associated with a scarcity of mosquitoes. the ib (epidemic) strain of vee virus was isolated from two pools ... | 1975 | 235213 |
| delayed-type hypersensitivity responses in mice infected with st. louis encephalitis virus: kinetics of the response and effects of immunoregulatory agents. | labeled monocyte infiltration techniques have been used to study delayed-type hypersensitivity responses in mice immunized with st. louis encephalitis virus. a delayed 24- to 48-h inflammatory response occurred 6 to 7 days after immunization. this response can be potentiated by cyclophosphamide treatment, by bcg administration, or by splenectomy. treatments known to selectivity inhibit t-cell function suppressed the response. | 1979 | 378848 |
| a simple method for the inactivation of st. louis encephalitis virus preparations for immunofluorescent microscopy. | a study was made of different treatments for the inactivation of st. louis encephalitis virus in smears prepared for immunofluorescence microscopy. treatment of infected cells with 0.3% betapropiolactone at 56 degrees c for 40 min resulted in an inactivated virus suitable for immunofluorescence studies. | 1978 | 383247 |
| st. louis encephalitis. | | 1979 | 398269 |
| survival of arboviruses in trypanosome-infected triatomines. | the potential of triatomines to maintain arboviruses was demonstrated by the ability of rhodinius prolixus with experimentally punctured abdomen to harbor venezuelan equine encephalitis (vee) virus for at least 4 months and st. louis encephalitis virus for 1 month. at 30 days after infection vee virus was found at low titers in trypanosoma cruzi-infected r. prolixus and at moderate titers in t. rangeli-infected r. neglectus. transmission of vee virus by bite of punctured bugs was successful 2 we ... | 1977 | 403822 |
| isolation of st. louis encephalitis virus in south brazil. | eight strains of a flavivirus identified as st. louis encephalitis (sle) virus were isolated from wild rodents, birds, and sentinel mice in three locations in the state of são paulo, brazil from 1967--1969. no illness attributable to sle virus infection was detected among the local inhabitants, although about 5% of the local population had neutralizing antibodies to this virus. | 1979 | 453451 |
| detection of arbovirus antibodies in avian sera by the complement fixation-inhibition test. | the complement fixation-inhibition (cfi) test was described for the detection of antibodies to arboviruses in bird sera. the cfi antibody present in bird sera inhibited the standard complement-fixation reaction of a reference complement-fixing antigen-antibody pair. using reference antigens (st. louis encephalitis, eastern equine encephalomyelitis, western equine encephalomyelitis, and yellow fever) prepared from infected mouse brains and reference antisera prepared in rabbits or horses, reprodu ... | 1979 | 464371 |
| st. louis encephalitis virus transmission following multiple feeding of culex pipiens pipiens (diptera: culicidae) during a single gonotrophic cycle. | | 1979 | 537010 |
| seroepidemiologic studies in oaxaca, mexico. ii. survey for arbovirus antibody. | a serologic survey was conducted in south-western mexico to obtain information on human experience with arbovirus infections. sera were collected from two semitropical areas along the pacific coast of oaxaca state, two mountain areas above 1,700 meters and the interior valley at 1,500 meters. of the 610 sera tested for group a antibody, 4.9 per cent were positive in the hemagglutination-inhibition (hi) test to venezuelan (ve), 11 per cent to eastern, and none to western encephalitis viruses. in ... | 1979 | 539866 |
| identification of saint louis encephalitis virus mrna. | saint louis encephalitis (sle) virus-specific rna was recovered from infected hela cells by sodium dodecyl sulfate (sds)-phenol-chloroform extraction, and the molecular species were resolved by sds-sucrose gradient centrifugation and agarose gel electrophoresis. sucrose gradient centrifugation revealed the presence of a 45s species, minor 20 to 30s heterogeneous species, and an 8 to 10 s rna species in the cytoplasmic extract. analysis of the same samples by electrophoresis on agarose gels, unde ... | 1978 | 625082 |
| isolation of st. louis encephalitis virus from overwintering culex pipiens mosquitoes. | two strains of st. louis encephalitis virus were isolated from overwintering mosquitoes collected in maryland and pennsylvania during january and february 1977. there isolations from culex pipiens constitute evidence that a mosquito-borne flavivirus can persist in a vector mosquito in temperate climates during the winter season. | 1978 | 628843 |
| transmission of northway and st. louis encephalitis viruses by arctic mosquitoes. | transmission of a canadian arctic isolate of northway virus has been demonstrated after incubation of arctic aedes communis mosquitoes at 13 degrees c for 27 days after intrathoracic injection of 300 plaque forming units of virus. replication has also been demonstrated after intrathoracic injection of domestic a. aegypti mosquitoes of this virus. virions of northway virus, 84--92 nm diameter were morphologically typical of a bunyavirus after propagation in salivary glands of a. communis or in ti ... | 1978 | 687117 |
| production of antibody in induced granulomas. | a method of producing antibodies in artificially induced granulomas with various microbial antigens is examined. | 1976 | 789397 |
| cellular resistance to arbovirus infection. | when an arbovirus enters an arthropod in an infected blood meal, several mechanisms may interact to affect its life cycle and ultimate transmissibility. intrinsic absolute failure in the establishment of infection must be contrasted with infection that is successfully established but is variably modulated in its viral yield throughout the vector's life-span. degrees of vertebrate host resistance make this modulation a central factor in determining whether an arthropod is an important vector in n ... | 1975 | 801110 |
| st. louis encephalitis in southern ontario: laboratory studies for arboviruses. | the first reported outbreak of st. louis encephalitis in canada occurred in the summer of 1975 in southern ontario -- in the windsor-sarnia-chatham area, the niagara region and the city of toronto. hemmagglutination inhibition and complement fixation testing of serum samples collected during the outbreak confirmed that st. louis encephalitis virus was the etiologic agent. furthermore, this virus was isolated from brain tissue of a patient who died. this outbreak was probably an extension of the ... | 1977 | 832217 |
| a comparison of saint louis encephalitis and sindbis virus rna. | rna isolated from purified st. louis encephalitis and sindbis virus particles was compared by cellulose cf-11 chromatography, and rnase t1 and pancreatic rnase a digestion. sle rna eluted from the cellulose cf-11 column as a molecule with very little secondary structure, while sindbis appears to have some internal bonding. ribonuclease digestion indicates that sle rna contains 2.4 per cent polyadenylic acid. | 1977 | 889439 |
| [reproduction and interferogenic activity of togaviruses]. | a comparative study of the correlation between reproduction and the interferon-inducing activity of viruses in chick embryo fibroblast cultures was carried out with members of different groups of togaviruses: alphavirus (venezuelan equin encephalomyelitis viru, vee) and flavivirus (saint louis encephalitis virus, sle). the correspondence between cycles of accumulation of intracellular and extracellular viruses and the dynamics of interferon production the synthesis of which began early in the st ... | 1977 | 898898 |
| serologic surveys for antibodies to western, eastern, california, and st. louis encephalitis and dengue 3 arboviruses in middle america, 1961-1975. | | 1977 | 922235 |
| arbovirus antibodies in children of rural guanabara, brazil. | school children living in guanabara state, brazil, have been tested for evidence of infection with 16 arboviruses. 3 percent were positive, and in every instance the positive reaction was attributable to st. louis encephalitis (sle) virus. evidence of familial aggregation was observed. | 1975 | 1184352 |
| intrauterine infection of mice with st. louis encephalitis virus: immunological, physiological, neurological, and behavioral effects on progeny. | intravenous injection of pregnant mice with st. louis encephalitis (sle) virus at 8 days of gestation resulted in infection of the fetus. progeny developed no antibody or tolerance to sle virus since the viral antigen was cleared by maternal antibody before antibody-forming competence developed in the young. temporary growth retardation was observed in a number of young at 3 weeks of age. after the initial setback the growth rate increased, indicating that early runting was due to an inability t ... | 1975 | 1193727 |
| transovarial transmission of arboviruses by mosquitoes: a review. | one interesting aspect of mosquito-borne arboviruses is their endemic persistence, espeically during adverse climatic conditions in the temperate zones. the hypothesis that transovarial transmission of alpha- and flaviviruses by their respective mosquito vectors could serve as an overwintering mechanism has been proposed; however, experimental data in support of this hypothesis are not very convincing. recently, some of the california encephalitis group arboviruses have been shown to be transmit ... | 1975 | 1207183 |
| st. louis encephalomyelitis in hermosillo, sonora, mexico. | this report, which describes an epidemic of st. louis encephalitis in northwestern mexico, was prompted by the apparent infrequency of previous mexican outbreaks of this disease. the site of the epidemic was the municipality of hermosillo in the state of sonora. this municipality, with a population of about 273,000, is situated in a hot flat area which is naturally dry but which is also well-irrigated. here, over an eithy-week period, 51 persons became ill and were hospitalized with symptoms inc ... | 1975 | 1212540 |
| 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 |
| use of the polymerase chain reaction for the sensitive detection of st. louis encephalitis viral rna. | polymerase chain reaction (pcr) assays were developed for the detection of rna from the st. louis encephalitis (sle) virus. using computer-assisted analysis of the msi-7 strain sle virus genome, two primer pairs were selected from the capsid-coding and the membrane associated protein-coding genes, and one from the envelope-coding gene. reverse transcription was primed with either specific oligomers or with random hexamers; these methods were compared for cdna synthesis and subsequent pcr amplifi ... | 1992 | 1348060 |
| mosquito and arbovirus ecology in southeastern california, 1986-1990. | mosquito abundance and western equine encephalomyelitis (wee) and st. louis encephalitis (sle) virus activity were monitored in five valleys in southeastern california from june 1986 through april 1990 to study virus overwintering and possible dissemination from south to north along geographically defined corridors. culex tarsalis coquillett predominated in co2 trap collections and was the only species repeatedly infected with wee and sle viruses. abundance peaked during april-may and august-oct ... | 1992 | 1352557 |
| virus-dependent mortality in rift valley fever, eastern equine encephalomyelitis, and chikungunya virus-inoculated mosquito (diptera: culicidae) larvae. | the effect of inoculation of mosquito larvae with rift valley fever (rvf) virus on survival to the adult stage was evaluated in aedes aegypti (l.), ae. fowleri (charmoy), ae. mcintoshi huang, ae. taeniorhynchus (wiedemann), ae. triseriatus (say), eretmapodites quinquevittatus theobald, anopheles albimanus wiedemann, and culex pipiens l. pupation rates were similar for rvf virus-inoculated and diluent-inoculated larvae of all mosquito species tested except cx. pipiens. however, with the exception ... | 1992 | 1357176 |
| detection of st. louis encephalitis virus in mosquitoes by use of the polymerase chain reaction. | we recently developed an assay using the polymerase chain reaction (pcr) for the specific detection of st. louis encephalitis (sle) virus rna. this assay was tested in a blind study on 7 samples of pooled mosquitoes (50 mosquitoes/pool) which were also characterized for sle virus by plaque assay in vero cell culture. one sample was positive for the sle virus as determined by both the pcr assay and a combination of the plaque assay and the indirect fluorescent antibody assay. the remaining 6 samp ... | 1992 | 1383418 |
| experimental inoculation of three arboviruses in black-bellied whistling ducks (dendrocygna autumnalis). | wild-caught, immature black-bellied whistling ducks (dendrocygna autumnalis) were inoculated with eastern equine encephalitis (eee), st. louis encephalitis (sle), or western equine encephalitis (wee) virus. susceptibility, duration and titer of viremia, and antibody response to these arboviruses were determined. birds from all inoculated groups became viremic. higher virus titers occurred in the eee group but overall mean titers were not significantly different among experimental groups. all bir ... | 1992 | 1474647 |
| ecology of mosquitoes and st. louis encephalitis virus in the los angeles basin of california, 1987-1990. | st. louis encephalitis (sle) virus has become established in the los angeles basin of california, where it most likely is maintained by horizontal transmission among culex tarsalis coquillet and passerine birds in park-riparian habitat. viral transmission also was detected at low levels in residential habitat by the infrequent seroconversion of sentinel chickens. sle virus activity was documented in all months except march and april. cx. tarsalis was incriminated as the primary vector, based on ... | 1992 | 1495066 |
| evaluation of domestic pigeons as sentinels for detecting arbovirus activity in southern california. | flocks of sentinel domestic pigeons (columbia livia) detected increases in st. louis encephalitis (sle) and western equine encephalomyelitis (wee) virus activity in southern california concurrently with flocks of sentinel chickens. however, occasional low-titered, transient seroconversions to both wee and sle viruses also occurred in pigeons during periods when virus activity was not detected by seroconversions in sentinel chickens, by virus isolation from culex mosquitoes, or by human disease. ... | 1992 | 1536386 |
| ecological observations on the 1989 outbreak of st. louis encephalitis virus in the southern san joaquin valley of california. | temporal and spatial patterns of st. louis encephalitis (sle) virus transmission were compared at permanent study areas in the southern san joaquin valley during years with low (1988 and 1990) and elevated (1989) viral activity. during 1989 and 1990, virus appeared first at sentinel chicken flocks exhibiting low to moderate seroconversion rates at the end of the previous season. this finding, and the early season seroconversion of sentinel chickens at a marsh habitat on 5 march and 2 april 1990, ... | 1992 | 1625296 |
| experimental studies to determine the susceptibility to infection with st. louis encephalitis virus of five species of panamanian mosquitoes. | the susceptibility to infection with a panamanian isolate of st. louis encephalitis (sle) virus was evaluated in culex quinquefasciatus, haemagogus equinus, mansonia dyari, sabethes cyaneus and deinocerites pseudes. when fed on blood-virus suspensions using the hanging drop or pledget technique, the median infective dose (id50) of sle virus for colonized strains of cx. quinquefasciatus and hg. equinus was 10(2.8) plaque forming units (pfu)/2 microliters and 10(3.5) pfu/2 microliters, respectivel ... | 1991 | 1686273 |
| distribution of st. louis encephalitis viral antibody in sentinel chickens maintained in sarasota county, florida: 1978-1988. | sentinel chicken flocks monitored arboviral transmission at 12 sites in sarasota county, fla., from 1978 through 1988. during this time, 3,452 serum samples were analyzed for hemagglutination inhibition antibody to st. louis encephalitis virus (sle) and eastern equine encephalomyelitis virus (eee). overall, 91 chickens seroconverted to sle and three to eee. the intensity of sle transmission showed considerable year-to-year variation. chickens from south-county flocks were more likely to seroconv ... | 1991 | 2033613 |
| preliminary studies of aedes bahamensis as a host and potential vector of st. louis encephalitis virus. | aedes bahamensis, a recent introduction to the state of florida, was studied to determine its capability to serve as a host or vector of st. louis encephalitis (sle) virus. females were readily infected by inoculation, and had whole body virus titers as high as 10(9.4) mosquito infectious doses 50. sixty percent of females that had been infected by inoculation were capable of orally transmitting virus. nearly half of the females feeding on viremic chickens became infected, but not all of these i ... | 1991 | 2045810 |
| vertical transmission of st. louis encephalitis virus to autogenously developed eggs of aedes atropalpus mosquitoes. | vertical transmission of st. louis encephalitis virus was demonstrated by a strain of aedes atropalpus mosquitoes from garrett county, md. five-day-old parental females containing fully formed autogenous eggs were infected by intrathoracic inoculation. st. louis encephalitis virus was detected in batches of fertilized eggs and fourth instar larvae. estimated filial infection rates of approximately 1% were observed for both eggs and larvae. | 1990 | 2098473 |
| venereal transmission of st. louis encephalitis virus by culex quinquefasciatus males (diptera: culicidae). | uninfected, virgin, colonized culex quinquefasciatus say females became infected when caged with males that had been infected with st. louis encephalitis (sle) virus by inoculation. when these females were assayed 7 or 28 d after first exposure to infected males, 23% and 25%, respectively, were infected with sle virus. fifty-eight percent (n = 83) of the inseminated females were infected with sle virus, whereas only 23% (n = 23) of virgin females were infected. these data show that at least some ... | 1990 | 2159075 |
| temporal variations in the susceptibility of a semi-isolated population of culex tarsalis to peroral infection with western equine encephalomyelitis and st. louis encephalitis viruses. | a semi-isolated population of culex tarsalis in kern county, ca was found to vary significantly in its seasonal and yearly susceptibility to peroral infection with western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses during the breeding seasons of 1975-1981. female cohorts of the population were significantly more resistant to wee virus from 1975 through 1977 than from 1978 through 1981. on the average, females were 40 times more susceptible to wee virus during may tha ... | 1990 | 2160200 |
| diel changes in adult mosquito microhabitat temperatures and their relationship to the extrinsic incubation of arboviruses in mosquitoes in kern county, california. | microhabitat temperatures experienced by nocturnally active culex tarsalis coquillett mosquitoes were measured in the southern san joaquin valley of california. temperatures of the diurnal resting shelter and nocturnal activity air space were measured by digital recorder at three cx. tarsalis habitats in kern county. temperatures measured by digital recorders agreed well with temperatures recorded concurrently at nearby california irrigation management and inspection system weather stations. mon ... | 1990 | 2167374 |
| low ph-induced cell fusion in flavivirus-infected aedes albopictus cell cultures. | cell-to-cell fusion of aedes albopictus (mosquito) cells infected with dengue and st louis encephalitis (sle) flaviviruses was induced by exposure to low ph. the parameters of this low ph-induced fusion were examined. syncytium formation was maximal in cultures 36 to 48 h post-infection and occurred when cultures were maintained at the acid ph for 15 min at 35 degrees c. the optimal ph range for fusion was 5.0 to 6.5 for dengue virus-infected cells and 5.0 to 5.5 for sle virus-infected cells. sy ... | 1990 | 2167941 |
| mosquito bionomics and the lack of arbovirus activity in the chino area of san bernardino county, california. | mosquito bionomics, including temporal abundance, metabolic status, and blood-feeding patterns, and arbovirus activity were studied at representative dairy and residential habitats in chino, calif., during 1987 and 1988. host-seeking culex tarsalis coquillett and cx. quinquefasciatus say females were more abundant and appeared earlier each season at traps near dairy breeding sources than at traps in residential areas, whereas cx. stigmatosoma dyar, which also breeds in dairy effluent, was most a ... | 1990 | 2231618 |
| persistence of mosquito-borne viruses in kern county, california, 1983-1988. | the persistence of arboviruses was studied from 1983 to 1988 in mixed agriculture, marsh, riparian, and foothill habitats in kern county, ca. western equine encephalomyelitis (wee) virus was isolated frequently during 1983 from culex tarsalis and aedes melanimon and was detected by the seroconversion of sentinel chickens. wee virus then disappeared, even though vector competence studies during 1984-1986 showed that cx. tarsalis was able to transmit wee virus. st. louis encephalitis (sle) virus w ... | 1990 | 2240370 |
| effect of the anesthetizing agent triethylamine on western equine encephalomyelitis and st. louis encephalitis viral titers in mosquitoes (diptera: culicidae). | triethylamine (tea) is a chemical compound that provides an effective means to anesthetize mosquitoes. the mosquitoes remain alive but are incapacitated for several hours; they do not recover following treatment. there was no effect on the titers of infectious virus recovered from western equine encephalomyelitis or st. louis encephalitis virus-infected culex tarsalis coquillett and aedes dorsalis (meigen) that were anesthetized with tea prior to storage at -70 degrees c. furthermore, tea had no ... | 1990 | 2280383 |
| rainfall-directed oviposition behavior of culex nigripalpus (diptera: culicidae) and its influence on st. louis encephalitis virus transmission in indian river county, florida. | resting culex nigripalpus theobald were collected with a ground aspirator three times a week in indian river county, fla., from january 1985 through december 1987. the number of green (newly emerged), empty, blood-fed, and gravid females in each collection was counted; up to 100 empty females were dissected to estimate the abundance of empty, parous females in the population. in general, this species was uncommon during the dry season from january through june but increased during the wet season ... | 1990 | 2299655 |
| epitope mapping of flavivirus glycoproteins. | | 1986 | 2428213 |
| 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 |
| antigenic structure of the murray valley encephalitis virus e glycoprotein. | to complement our battery of st louis encephalitis (sle) virus monoclonal antibodies (mabs), we isolated and characterized mabs reactive with another member of the sle virus serocomplex, murray valley encephalitis (mve) virus. from 40 fusion products, we isolated 10 stable hybridomas. the combination of sle and mve virus mabs defined eight epitopes on the mve envelope (e) glycoprotein. six of these epitopes (e-1a, e-1c, e-1d, e-3, e-4a, e-4b) were identical to those previously demonstrated on sl ... | 1988 | 2453607 |
| delaying virus maturation for a higher yield of cell associated virus antigens. | negligible amounts of virus were released when infected cells were maintained in low ionic strength medium. the cells accumulated a high titre of virus and its specific antigenic proteins, detected by complement-fixation test. the procedure has potential for production of virus subunit vaccines. | 1989 | 2481802 |
| kunjin virus isolates of australia are genetically homogeneous. | the genomes of 22 isolates of kunjin virus (kun) from australia were characterized and compared using rnase t1 oligonucleotide fingerprinting. the results show that all isolates belonged to one topotype, the distribution of which covered the entire australian continent. this finding is similar to that of murray valley encephalitis virus, but in contrast to the results reported for some other flaviviruses such as saint louis encephalitis virus. | 1989 | 2552010 |
| [serologic study of arbovirus in 2 localities of the juventud island]. | a serologic study is made in two population groups in the isle of youth. a total 268 blood samples in blotting paper are subjected to the hemagglutination inhibition technique, using the eastern equine encephalomyelitis, western equine encephalomyelitis, saint louis encephalitis, and dengue 2 viruses; 16% positivity to flavivirus was found. a second serum sample was taken in people positive by the hemagglutination inhibition technique in order to carry out the techniques of complement fixation a ... | 1989 | 2561798 |
| surveillance of st. louis encephalitis virus vectors in grand junction, colorado, in 1987. | grand junction, colorado, was the site of a st. louis encephalitis (sle) outbreak in 1985. epidemiologic and ecologic investigations in 1985 and 1986 suggested that culex tarsalis may not have been the exclusive vector in the outbreak and that cx. pipiens may have contributed to transmission as an accessory vector. a limited field study in 1987 generally confirmed observations from 1986 that cx. pipiens was more abundant than cx. tarsalis in late summer when sle virus transmission normally occur ... | 1989 | 2746202 |
| nucleotide and complete amino acid sequences of kunjin virus: definitive gene order and characteristics of the virus-specified proteins. | a kunjin (kun) virus cdna sequence of 10664 nucleotides was obtained and it encoded a single open reading frame for 3433 amino acids. partial n-terminal amino acid analyses of kun virus-specified proteins identified the polyprotein cleavage sites and the definitive gene order. the gene order relative to that proposed for yellow fever (yf) virus is as follows: kun 5'-c.gp20.e.gp44.p19.p10.p71.(?).p21.p98-3' yf 5'-c.prm.e.ns1.ns2a.ns2b.ns3.ns4a.ns4b. ns5-3'. the order of putative signal sequences ... | 1988 | 2826659 |
| evidence that the mature form of the flavivirus nonstructural protein ns1 is a dimer. | evidence is presented which indicates that the dengue-2 virus nonstructural protein ns1 (soluble complement fixing antigen) exists in infected bhk and mosquito cell cultures as part of a stable oligomer. identification of the dissociation products of the isolated oligomer and comparison of the number of n-linked glycans in native and denatured ns1 is consistent with the idea that the high-molecular-weight form of ns1 is a homodimer. by analyzing lysates of bhk cells infected with st. louis encep ... | 1988 | 2827377 |
| sequence and secondary structure analysis of the 5'-terminal region of flavivirus genome rna. | the 5'-terminal noncoding region sequences were determined for the genome rnas of seven strains of st. louis encephalitis virus (slev) and one strain of west nile virus (wnv) using a single synthetic cdna primer complementary to the 5'-terminus of the coding region of a strain of wnv rna. the 5'-terminal sequences obtained for the slev and wnv rnas were compared with published sequences for yellow fever virus (yfv), murray valley encephalitis virus (mvev), and dengue virus. while only short regi ... | 1988 | 2829420 |
| a rapid dot immunoassay for the detection of serum antibodies to eastern equine encephalomyelitis and st. louis encephalitis viruses in sentinel chickens. | a dot enzyme-linked immunosorbent assay utilizing a novel membrane, polyvinylidene difluoride, is described. this assay was developed for the rapid detection of serum antibodies to eastern equine encephalomyelitis virus and st. louis encephalitis virus in sentinel chickens. antigens were spot-filtered through the membrane. membranes were dipped into small vials of sera. antigen-antibody complexes were detected with enzyme-conjugated antiglobulin which, when exposed to substrate, produced a color ... | 1988 | 2829636 |
| the st. louis encephalitis epidemic. | | 1988 | 2839532 |
| further observations on the mechanism of vertical transmission of flaviviruses by aedes mosquitoes. | as previously observed for dengue viruses, vertical (i.e., transgenerational) transmission of japanese and st. louis encephalitis viruses by aedes albopictus takes place when the fully formed egg, enclosed in the chorion, is oviposited. the demonstration of such a mechanism for three flaviviruses suggests that vertical transmission of all mosquito-borne flaviviruses may occur in the same manner. | 1988 | 2840833 |
| establishment and characterization of st louis encephalitis virus persistent infections in aedes and culex mosquito cell lines. | persistent infections with st louis encephalitis (sle) virus were established in three mosquito cell lines (aedes albopictus, a. dorsalis and culex tarsalis) and were maintained for over 2 years. all three persistently infected cell cultures shared two features: (i) no overt cytopathic effect and (ii) a relatively high proportion of cells infected (41 to 85%). the aedes persistently infected cultures were resistant to superinfection with the homologous virus but not heterologous viruses. two sig ... | 1988 | 2842432 |
| phenotypes of st louis encephalitis virus mutants produced in persistently infected mosquito cell cultures. | viral mutants that appeared during long-term persistent infections of mosquito cell cultures (aedes albopictus, a. dorsalis and culex tarsalis) with st louis encephalitis virus were characterized. evidence was obtained for the presence of temperature-sensitive mutants in the a. dorsalis and c. tarsalis persistently infected cultures, and small plaque mutants were predominant in all cultures except one of two cell cultures of c. tarsalis. virus from persistently infected a. albopictus cell cultur ... | 1988 | 2842433 |
| antibody prevalence of st. louis encephalitis virus in avian hosts in los angeles, california, 1986. | a study was conducted to determine the pattern of st. louis encephalitis (sle) virus activity in the avian populations of the los angeles metropolitan area in 1986. in total, 679 birds of 42 species were captured at 7 study sites. the overall prevalence of sle neutralizing (n) antibody of 3% indicated enzootic transmission. antibody prevalences were higher in birds sampled in the central part of the metropolitan area, which was consistent with other epidemiologic data. the use of specific avian ... | 1988 | 2852209 |
| stability of st. louis encephalitis viral antigen detected by enzyme immunoassay in infected mosquitoes. | the use of enzyme immunoassay to detect st. louis encephalitis (sle) viral antigen in vector mosquitoes enhances the effectiveness of surveillance because infected mosquitoes can be identified more rapidly than with conventional virus isolation systems and because it is a simple and accessible procedure. infectivity among mosquitoes experimentally infected with sle virus was lost within 24 h after the mosquitoes were stored at 27 degrees c and 80% relative humidity; however, viral antigen remain ... | 1988 | 2852675 |
| the importance of autumn rainfall and sentinel flock location to understanding the epidemiology of st. louis encephalitis virus in indian river county, florida. | culex nigripalpus adults were collected from sentinel chickens at 4 sites in indian river co. (irc), florida. chickens located in well drained, open habitats attracted fewer cx. nigripalpus than did those located in a moist, forested area, but the number of mosquitoes collected in the open habitats increased significantly with heavy autumn rainfall. all st. louis encephalitis virus (sle) seroconversions (11/674) during a 7-year period were from chickens located in open, well drained habitats. a ... | 1985 | 2852706 |
| flavivirus vaccines. | diseases caused by flavivirus infection have been a scourge of mankind for over three centuries; with yellow fever, dengue fever and russian spring-summer encephalitis causing epidemics resulting in thousands of fatalities. due to the development of a safe and efficacious live-attenuated vaccine against yellow fever, this disease is no longer such a threat in countries where adequate vaccination is practised. a similarly safe and efficacious inactivated vaccine against central-european tick-born ... | 1988 | 2854336 |
| comparative susceptibility of five species of toxorhynchites mosquitoes to parenteral infection with dengue and other flaviviruses. | five species of colonized toxorhynchites mosquitoes were compared for relative susceptibility to parenteral infection with the four dengue serotypes and st. louis and japanese encephalitis viruses. tx. amboinensis, tx. brevipalpis, tx. rutilus, and tx. splendens were equally susceptible to infection with the dengue viruses, while tx. theobaldi was relatively resistant to infection with those viruses. all five mosquito species were equally susceptible to infection with the encephalitis viruses. t ... | 1985 | 2862802 |
| arbovirus investigations in argentina, 1977-1980. ii. arthropod collections and virus isolations from argentine mosquitoes. | prospective surveys for arboviruses were carried out in santa fe, corrientes, and chaco provinces, argentina, aperiodically during 1977-1980. a total of 313,233 mosquitoes and 598 biting flies other than mosquitoes were collected and tested for virus in 5,197 and 45 pools, respectively. forty virus strains were isolated, all from mosquitoes, as follows: santa fe province: 4 gamboa group viruses from aedeomyia squamipennis, 1 strain each of st. louis encephalitis virus from culex pipiens quinquef ... | 1985 | 2863989 |
| arbovirus investigations in argentina, 1977-1980. iii. identification and characterization of viruses isolated, including new subtypes of western and venezuelan equine encephalitis viruses and four new bunyaviruses (las maloyas, resistencia, barranqueras, and antequera). | forty viruses isolated from mosquitoes between 1977 and 1980 in argentina have been identified and characterized. nineteen strains of vee virus, identical by neutralization (n) tests, were shown by hemagglutination-inhibition tests with anti-e2 glycoprotein sera to represent a new subtype vi of the vee complex. rna oligonucleotide fingerprints of this virus were distinct from subtype i viruses. the virus was not lethal for english short-haired guinea pigs, indicating that it is probably not equi ... | 1985 | 2863990 |
| arbovirus investigations in argentina, 1977-1980. iv. serologic surveys and sentinel equine program. | serologic surveys of wild and domestic birds, wild mammals, and horses were conducted during arbovirus field studies in argentina from 1977 through 1980, a non-epizootic interval. the prevalence of neutralizing antibodies to eastern equine encephalitis (eee) was consistently higher than to western equine encephalitis (wee) virus in all species and all areas. the presence of antibodies in short-lived avian species and in young unvaccinated horses and the demonstration of seroconversions in horses ... | 1985 | 2863991 |
| entomological studies at an enzootic venezuelan equine encephalitis virus focus in guatemala, 1977-1980. | the ecology of several potential mosquito vectors of venezuelan equine encephalitis (vee) alphavirus was studied in an enzootic focus of that virus on the pacific coast of guatemala over a four-year period. four species-culex taeniopus, mansonia titillans, culex nigripalpus and aedes taeniorhynchus-were most prevalent during the wet season when transmission normally occurs. however, only cx. taeniopus yielded vee virus. the bloodfeeding patterns of these species revealed that ae. taeniorhynchus ... | 1986 | 2873752 |
| experimental vertical transmission of saint louis encephalitis virus by florida mosquitoes. | vertical transmission of st. louis encephalitis (sle) virus to f1 larval progeny was demonstrated in 8 species of mosquitoes which occur in florida: culex quinquefasciatus, cx. nigripalpus, cx. salinarius, cx. restuans, cx. opisthopus, anopheles quadrimaculatus, an. albimanus, and aedes taeniorhynchus. relatively high rates of such transmission were observed in ae. taeniorhynchus and vertical transmission to f1 adult progeny and venereal transmission from males to females also were demonstrated ... | 1986 | 2878627 |
| arbovirus isolations from mosquitoes collected during and after the 1982-1983 epizootic of western equine encephalitis in argentina. | mosquitoes were collected in santa fe and rio negro provinces, argentina, in 1982-1983 during a western equine encephalitis (wee) epizootic. totals of 153,084 mosquitoes from santa fe province and 484 from rio negro province were tested for virus in 2,351 pools. seventeen virus strains were isolated, all from santa fe collections, as follows: 4 wee, 6 venezuelan equine encephalitis, 1 st. louis encephalitis, 2 antequera, 1 maguari, 1 melao, 1 new vesiculovirus (calchaqui), and 1 gamboa. the wee ... | 1987 | 2880521 |
| epidemiologic aspects of a st. louis encephalitis outbreak in mesa county, colorado. | an epidemic of st. louis encephalitis in 1985 in mesa county, colorado, led to 17 cases, including one fatality. risk was associated with advanced age and residence in grand junction, the county's principal city. a trend was observed toward higher risk in females. however, increased risk in females was not associated with higher infection rates (increased exposure). capture enzyme immunoassays detected specific immunoglobulin m (igm) and immunoglobulin a after infection. a serosurvey of grand ju ... | 1987 | 2887107 |
| the discovery decade of arbovirus research in western north america, 1940-1949. | | 1987 | 2891315 |
| entomologic studies after a st. louis encephalitis epidemic in grand junction, colorado. | in 1986, after a st. louis encephalitis epidemic in grand junction, colorado, in 1985, vector mosquitoes in the city were surveyed to correlate their bionomics and infection rates with the occurrence of human disease. no human cases were reported, but mosquito surveillance disclosed st. louis encephalitis virus in culex tarsalis and culex pipiens pipiens. mosquitoes were collected with gravid traps designed to attract cx. p. pipiens and with centers for disease control light traps. culex p. pipi ... | 1988 | 2899394 |
| isolation of st. louis encephalitis virus from adult dermacentor variabilis (acari: ixodidae). | | 1985 | 2984423 |
| premortem isolation of saint louis encephalitis virus: case report and implications for hospital and laboratory personnel. | | 1985 | 2995935 |
| amino-terminal amino acid sequences of structural proteins of three flaviviruses. | n-terminal amino acid sequences of structural proteins of three flaviviruses, yellow fever, st. louis encephalitis, and dengue-2 viruses, have been obtained. the glycoproteins of these three viruses are 52-60% conserved in the region sequenced, depending upon which pair of viruses are compared, and 40% of the amino acids are invariant in all three viruses. thus, flaviviruses are closely related and have in all probability descended from a common ancestor. furthermore, residues important in the s ... | 1985 | 2998002 |
| partial n-terminal amino acid sequences of three nonstructural proteins of two flaviviruses. | partial n-terminal amino acid sequences for the three largest nonstructural proteins of two flaviviruses, yellow fever virus and st. louis encephalitis virus, have been obtained. the determined sequences of these proteins exhibit significant amino acid sequence homology, and allow the positioning of these three nonstructural proteins in the polyprotein sequence deduced from the nucleotide sequence of yellow fever virus (c. m. rice, e. m. lenches, s. r. eddy, s. j. shin, r. l. sheets, and j. h. s ... | 1986 | 3008425 |
| arbovirus infections in several ontario mammals, 1975-1980. | serological studies for arboviruses were conducted on 725 animal sera collected in 22 ontario townships between 1975 and 1980 including 44 coyote (canis latrans), 277 red fox (vulpes vulpes), 192 raccoon (procyon lotor) and 212 striped skunk (mephitis mephitis). hemagglutination inhibition antibodies to two flaviviruses, namely st. louis encephalitis and powassan were found in 50% of coyote, 47% of skunk, 26% of fox and 10% of raccoon sera. similarly, hemagglutination inhibition antibodies to a ... | 1986 | 3017527 |
| relevance of detection of immunoglobulin m antibody response in birds used for arbovirus surveillance. | young chickens were inoculated with 5,000 pfu of eastern equine encephalitis (eee) virus and bled at intervals thereafter for determinations of hemagglutination-inhibiting (hi), neutralizing (n), immunoglobulin m (igm), and igg antibodies. hi, n, and igm antibodies were first detected 4 days after infection, and igg was detected 7 days after infection. all four antibodies persisted through day 90 after infection. hi, n, and igm antibody titers remained elevated and were not cross-reactive with t ... | 1986 | 3021813 |
| [meningoencephalitis caused by the st. louis encephalitis virus]. | | 1985 | 3022104 |
| partial nucleotide sequence of st. louis encephalitis virus rna: structural proteins, ns1, ns2a, and ns2b. | cdna clones of the st. louis encephalitis (sle) virus genome have been obtained and the nucleotide sequence of 4.7 kb corresponding to the 5' terminal half of the genome determined. the genome contains a 5' noncoding region of 98 nucleotides followed by a single continuous open reading frame that encodes three structural proteins in the order capsid (c), membrane precursor (prm)-membrane (m), and envelope (e). immediately following the c-terminus of e are located nonstructural proteins ns1 throu ... | 1987 | 3027980 |
| detection of st. louis encephalitis virus antigen in mosquitoes by capture enzyme immunoassay. | surveillance methods that measure st. louis encephalitis (sle) virus activity in nature may provide forewarning of its epidemic occurrence in humans. an antigen capture enzyme immunoassay was developed to detect sle virus in infected mosquitoes. the assay detected purified sle viral antigen at a concentration of 62 pg/0.1 ml when antigen was incubated overnight; 250 pg/0.1 ml was detected in a single-day assay (antigen incubated for 3 h). the assay detected 67.9 and 70.8% of laboratory-prepared ... | 1987 | 3029170 |
| st. louis encephalitis: lessons from the last decade. | in 1980 reeves wrote that epidemics of st. louis encephalitis (sle) are preventable by means of surveillance and vector abatement. this view is examined in the light of epidemic activity during the last decade (1977-1986), in which 9 discrete outbreaks occurred. in addition, 5 interactive factors (virus, vector, viremic host, human immunity, environmental temperature) described by reeves as essential to the development of an sle epidemic are reviewed in the light of recent research. although muc ... | 1987 | 3318523 |
| susceptibility of aedes albopictus c6/36 cells to viral infection. | the susceptibility of the c6/36 clone of aedes albopictus monolayer cell cultures was determined with 46 prototype viruses passed through three subcultures. viral growth was confirmed by titration of the passage material in other susceptible host systems. nineteen viruses demonstrated good growth in c6/36 cells: coxsackievirus group a type 10 and group b types 2, 3, 4, and 5; enterovirus 69; mumps virus; poliovirus types 1 to 3; reovirus types 1 to 3; vaccinia virus; dengue virus type 2; eastern ... | 1987 | 3611315 |
| isolation of cache valley virus and detection of antibody for selected arboviruses in michigan horses in 1980. | blood samples collected in september and november 1980 from 87 horses in southwestern michigan were examined for virus isolation and for plaque-reduction neutralizing antibody against selected arboviruses. cache valley virus was isolated from the blood of a clinically normal horse in st joseph county in september. the age-specific antibody prevalence for cache valley virus indicated enzootic transmission in the study area. the high antibody prevalence and the lack of age-specific antibody preval ... | 1987 | 3631684 |
| viremic enhancement due to transovarially acquired antibodies to st. louis encephalitis virus in birds. | adult house sparrows (passer domesticus) were captured and experimentally inoculated with st. louis encephalitis (sle) virus to produce high concentrations of circulating antiviral antibody. nestlings, 5-7 and 14-16 days of age, from sle immune adult females and challenged with sle virus, exhibited viremic enhancement by producing viremias of greater duration and magnitude than did controls. nestlings possessing maternal antibody and challenged with sle virus between 8 and 13 days of age did not ... | 1986 | 3735578 |
| distribution of dopa-oxidase isozymes among mosquito vectors of viral encephalitis. | distribution of dopa-oxidase isozymes in larval culex pipiens pipiens, culex pipiens quinquefasciatus and their hybrids was determined by agarose gel electrophoresis. three zones of enzyme activity were detected in the subspecific and hybrid populations. zone i was cathodic whereas zones ii and iii were anodic. electrophoretic variability was evident only in zone ii which was dimorphic for enzyme activity. zones i and iii were monomorphic. the subspecific and hybrid populations were distinguisha ... | 1985 | 3917888 |
| experimental studies of st. louis encephalitis virus in vertebrates. | serologically negative birds and mammals of species, known from other studies to be exposed naturally to st. louis encephalitis (sle) virus in memphis, tennessee, and other selected species were inoculated experimentally with strains of sle virus to determine their potential as natural hosts. mosquitoes (culex sp.) were allowed to feed on some of the inoculated vertebrate species, held for 14 days, and tested for sle infection. the cardinals (richmondena cardinalis), robins (turdus migratorius), ... | 1985 | 3999258 |
| arbovirus investigations in argentina, 1977-1980. i. historical aspects and description of study sites. | this is the introductory paper to a series on the ecology of arboviruses in argentina. epizootics of equine encephalitis have occurred since at least 1908, principally in the pampa and espinal biogeographic zones, with significant economic losses; human cases of encephalitis have been rare or absent. both western equine and eastern equine encephalitis viruses have been isolated from horses during these epizootics, but the mosquitoes responsible for transmission have not been identified. a number ... | 1985 | 4037184 |
| group b arbovirus structural and nonstructural antigens. i. serological identification of saint louis encephalitis virus soluble antigens. | saint louis encephalitis virus-infected cells were solubilized with brij-58 nonionic detergent, and the clarified supernatant fluid was analyzed by diethyl-aminoethyl-cellulose chromatography. three serologically distinguishable antigens were identified in viral protein peaks which eluted from diethylaminoethyl-cellulose at 0.05, 0.075, 0.125 and 0.2 m kcl. antigen i was found in all column peaks, whereas antigen ii was found only in the 0.05 m kcl eluate and antigen iii was found only in the 0. ... | 1973 | 4121413 |
| group b arbovirus structural and nonstructural antigens. ii. purification of saint louis encephalitis virus intracellular antigens. | three serologically distinct antigens were identified in homogenates of saint louis encephalitis (sle) virus-infected cells after brij-58 solubilization and diethylaminoethyl (deae)-cellulose chromatography. these antigens were designated as antigen i, ii, and iii. immunodiffusion analyses showed that all antigen peaks which eluted from the deae-cellulose column contained the intracellular major envelope protein, antigen i. this protein was the only viral antigen which eluted at 0.125 m kcl in d ... | 1973 | 4131772 |
| group b arbovirus structural and nonstructural antigens. 3. serological specificity of solubilized intracellular viral proteins. | solubilized nonstructural antigen iii from saint louis encephalitis (sle)-japanese b encephalitis (jbe)-west nile (wn) and dengue-2 arbovirus-infected pig kidney cells was purified by employing brij-58 solubilization, organic solvent extraction, and column chromatography. diethylaminoethyl-cellulose column peak c eluate contained only intracellular viral envelope protein designated antigen i. antigen i of sle virus absorbed homologous neutralizing antibody; however, the intracellular nonstructur ... | 1973 | 4131773 |