| mosquito-borne arboviruses in arctic america. | mosquito-borne arboviruses are prevalent throughout subarctic regions of canada and alaska, principally in the boreal forest extending between latitudes 53 and 66 degrees n, but they have been identified in tundra regions as far north as 70 degrees n. all mosquito-borne agents have been bunyaviruses, comprising principally the snowshoe hare subtype of california encephalitis (ce) virus, but also northway virus. mosquito vectors comprise several aedes species and culiseta inornata, all of which h ... | 1975 | 1602 |
| overwintering of mosquito-borne viruses. | | 1975 | 1603 |
| pig kidney epithelial (ps) cells: a perfect tool for the study of flaviviruses and some other arboviruses. | | 1975 | 1999 |
| california arbovirus (la crosse) infections. iii. epidemiology of california encephalitis in minnesota. | mosquitoes (eggs, larvae, and adults), small woodland animals, and residents of an area where california encephalitis is endemic were studied to elucidate the host-vector cycle of la crosse virus. elementary schoolchildren from surrounding communities and gray squirrels from another area were tested to compare the prevelence of serum antibodies to la crosse virus in areas where the disease is endemic with the prevalence of these antibodies in areas where the disease is not endemic. from 1971 to ... | 1976 | 3613 |
| tahyna virus in tissue explants of experimentally infected suckling mice. | | 1976 | 7945 |
| the ecology and medical importance of the tahyna virus (author's transl). | in 1958 a virus transmitted by a mosquito was isolated in the slovakian village of tahyna. since this virus was unknown in europe, a detailed study was begun. it was shown that this virus belonged to the california group of arboviruses and occurs in practically all european countries. it could very well be that young hares are the hosts for this virus, and that it multiplies in them. foals and suckling pigs are also hosts and possibly also increase the virus. in patients observed so far, infecti ... | 1976 | 12467 |
| influence of temperatures corresponding to those of the host animals on tahyna virus. | the influence of temperature of 36.5 and 39.2 degrees c on uncloned low passage tahyna virus in chick embryo cell cultures was studied in the course of 10 passages. at a high multiplicity of infection, the virus titres showed a considerable variability, especially at 39.2 degrees c. the cytopathic effect (cpe) apparent at both temperatures started later and was of lower intensity at 39.2 degrees c than at 36.5 degrees c. the temperature of 39.2 degrees c intensified the thermostable character of ... | 1976 | 13644 |
| influence of temperature corresponding to that of the vector on tahyna virus. | the behaviour of uncloned, low-passage tahyna virus in an aedes albopictus (aa) cell line at 28 and 20 degrees c was studied in the course of 10 passages. the virus multiplied at both temperatures without any apparent effect on the host cell. at 28 and 20 degrees c reduction of plaque size, decrease of peripheral virulence and weakening of thermostability were observed. differences between both temperatures were only in the intensity of these changes. | 1976 | 13645 |
| experimental hazara virus infection in mice. | reproduction of hazara virus in intracerebrally (ic) inoculated newborn white mice was studied by virological, serological and histological methods, electron microscopy and the direct fluorescent antibody technique. in the course of infection the virus was detectable in the blood, brain and some viscera, the largest amounts of virus occurring in the brain and liver. pathomorphological lesions were localized in the brain and consisted of foci of neuronal destruction and marked oedema of the tissu ... | 1977 | 17280 |
| bunyavirus isolations from mosquitoes in the western canadian arctic. | strains of california encephalitis virus (snowshoe hare subtype) were isolated from 8 of 475 pools comprising 23 747 unengorged female mosquitoes of five species collected at three of six locations throughout the mackenzie valley of the northwest territories, canada, from latitudes 60 to 69 degrees n between 10 and 24 july 1976. minimum field infection rates included 1:2734 for aedes communis, 1:256 to 1:3662 for a. hexodontus and 1:911 to 1:1611 for a. punctor. northway virus was also isolated ... | 1977 | 18541 |
| ecology of keystone virus, a transovarially maintained arbovirus. | our studies in the pocomoke cypress swamp of maryland have shown that key strain of ce is endemic and is carried by the floodwater mosquito a. atlanticus. the virus is transmitted transstadially in nature, as evidenced by our recovery of virus from larvae and males of this species. serologic evidence, both here and elsewhere, indicates that vertebrates are infected with key, but their role in the transmission cycle remains unknown. we have found several animals, for example, the gray squirrel, t ... | 1975 | 20017 |
| mosquito-virus relationships of american encephalitides. | | 1978 | 24407 |
| virological examination of mosquito larvae from southern moravia. | 254 pools of 4,115 mosquito larvae belonging to nine species were examined by isolation experiments. the larvae were collected in breeding places in an inundated forest--a natural focus of tahyna virus, in april, june and july 1974 and 1975. tahyna virus was isolated from one pool of 10 culiseta annulata larvae collected in july 1974. ecological questions concerning this finding are discussed. | 1978 | 25228 |
| infection rates of aedes triseriatus following ingestion of la crosse virus by the larvae. | infection rates ranged from 0-2.1% in adults of aedes triseriaus reared from groups of larvae that had ingested la crosse (lac) virus (clifornia encephalitis group) at dosages of 7.0-8.3 log 10 smicld50/ml. females form orally infected larvae transmitted the virus to suckling mice. larvae that devoured carcasses of transovarially infected larvae containing 3.0 log 10 smicld 50/ml failed to become infected. ingestion by larvae of infected carcasses appears, therefore, to be unimportant as a metho ... | 1978 | 27990 |
| experimental studies of the interrelationships of the tahyna virus with mosquitoes. | | 1978 | 28468 |
| arbovirus isolations from mosquitoes in south slovakia. | in the years 1973 and 1975 mosquitoes and some other diptera (tabanidae, simuliidae, hippoboscidae) were tested for virus. 13,924 mosquitoes, 75 horseflies and 60 blackflies were processed in 1973. five strains of tahyna virus were isolated from mosquito species aedes vexans. 3,378 mosquitoes and 12 sheep keds were tested for virus in 1975. twelve strains of calovo virus were isolated from anopheles maculipennis and one strain of tahyna virus was obtained from aedes vexans mosquitoes. | 1978 | 28998 |
| california encephalitis group viruses isolated from mosquitoes collected in southern and arctic norway. | three virus strains serologically related to the california encephalitis group (bunyaviridae) of arboviruses were isolated from 7331 mosquitoes collected in norway in june-august 1975. two of the isolates (s 548 and s 618) seemed to be closely related and the third, s 568, more distantly related by serological techniques to tahyna virus. viruses were found in the mosquito species aedes sticticus, a. diantaeus and a. hexodontus colllected (in order) from oyern (59 degrees n, 11 degrees 12' e), tr ... | 1978 | 31761 |
| california encephalitis virus activity in mosquitoes and horses in southern ontario, 1975. | a study was undertaken in 1975 to determine california encephalitis virus activity in southern ontario. three thousand and sixty-one mosquitoes, primarily aedes species, were divided into 104 pools and inoculated into suckling mice. isolates of snowshoe hare virus were obtained from one pool each of aedes fitchii and a. triseriatus mosquitoes collected in the guelph area. serological testing of horse sera revealed extensive virus activity in southern ontario and indicated that horses may serve a ... | 1978 | 34475 |
| experimental infection of putorius eversmanni polecats and martes foina martens with tahyna virus. | three putorius eversmanni pole-cats and two martes foina martens aged about 9 months were subcutaneously infected with about 260 suckling mouse ld50 of the extraneurally passaged "236" strain of tahyna virus (california group, genus bunyavirus). viraemia with maximal titres of 1.32 (pole-cats) and 1.28 (martens) dex intraperitoneal (i.p.) mouse ld50/0.02 ml was demonstrated from 48 to 96 hr after inoculation (p.i.). by the plaque-reduction neutralization test, seroconversion was demonstrated 15 ... | 1978 | 35949 |
| experimental transmission of tahyna virus (california group) to wild rabbits (oryctolagus cuniculus) by mosquitoes. | two wild rabbits (oryctolagus cuniculus) were subcutaneously infected with a dose of 2.6 dex. i.c. ld50/0.02 ml of extraneurally passaged tahyna virus strain "236". during the 24-72 hours interval p.i. viremia was demonstrated in both animals ranging from 1.0 to 3.42 dex. i.e. ld50/0.02. mosquitoes aedes vexans, which had fed on them, transmitted the virus to one of three other rabbits. during 24-96 hours interval after terminated feeding of infectious mosquitoes viremia was detected in this ani ... | 1979 | 36333 |
| the ecology of california group viruses. | | 1979 | 42800 |
| bunyavirus development in arctic and aedes aegypti mosquitoes as revealed by glucose oxidase staining and immunofluorescence. | northway virus replication has been detected in salivary glands of wild-caught culiseta inornata and aedes communis mosquitoes from the western canadian arctic after incubation at 4 degrees c for 9 to 11 months, and after incubation at 13 degrees c for 3 to 4 months after they received virus by oral ingestion or intrathoracic injection. aedes hexodontus supported northway virus replication after incubation at 13 degrees c for one month after intrathoracic injection. aedes aegypti supported north ... | 1979 | 44464 |
| selection of la crosse virus variants by sentinel squirrels (sciuris carolinensis) and chipmunks (tamius striatus). | comparisons of la crosse (lac) virus strains, obtained from sentinel squirrels and chipmunks, were made using three viral markers: plaque size on vero cells, virulence in 8 days old laboratory mice, and antigenic characteristics as measured by the plaque reduction neutralization test. all strains were in their first suckling mouse brain passage. the mean plaque size of viruses isolated from squirrels was slightly larger than the mean plaque size of viruses isolated from chipmunks. there were no ... | 1977 | 68669 |
| [use of suspension adsorption methods for studying arboviruses]. | hemagglutinating antigens of western equine encephalomyelitis (wee) virus and 5 strains of tick-borne encephalitis (tbe) virus were charcaterized by their capacity to adsorb on inorganic (kaolin, bentonite, barium sulphate) and organic (chick embryo fibroblasts) adsorbents. the adsorption capacity of tbe virus was more marked than that of wee. the tbe virus strains 4072 and 1524 avid in serological tests adsorbed better on inorganic adsorbents than nonavid strains no. 80 and 1509. in contrast, n ... | 1977 | 72456 |
| cross-neutralization study of seven california group (bunyaviridae) strains in homoiothermous (ps) and poikilothermous (xtc-2) vertebrate cells. | antigenic relationships among seven california group strains were studied by a plaque-reduction neutralization test (prnt). cross-reactions occurred in most cases but three subgroups were noted: (1) the major serogroup contained the viruses of california encephalitis, lacrosse, snowshoe hare and trahyna (including the lumbo strain) whereas (2) jamestown canyon and (3) trivittatus viruses were distinct. there was no significant difference between the prnt results in mammalian (ps) cells incubated ... | 1979 | 84857 |
| infection rates of ascocystis-infected aedes triseriatus following ingestion of la crosse virus by the larvae. | the la crosse (lac) virus infection rate of aedes triseriatus larvae that ingest lac virus does not appear to be increased by concomitant infection of larvae by the gregarine parasite, ascocystis barretti. infection rates ranged only from 0--2.6% in adult ae. triseriatus reared from groups of a. barretti-infected larvae that had ingested lac virus (california encephalitis group) at dosages of 2.0--7.7 log10 smicld50/ml. females resulting from orally infected larvae transmitted lac virus to suckl ... | 1979 | 116554 |
| [the use of polyethylene ampoules in virolgy (author's transl)]. | | 1977 | 137778 |
| [isolation of tahyna virus (california antigenic group, family bunyaviridae) from the blood of febrile patients in the tadzhik ssr)]. | | 1977 | 146311 |
| [tahyna virus -- neutralizing antibodies of patients in southern moravia (author's transl)]. | | 1979 | 156083 |
| [serologic surveys for the determination of antibodies against the eastern, western, california and st. louis encephalitis and dengue 3 arboviruses in central america, 1961-1975]. | | 1979 | 159062 |
| 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 |
| international arbovirus research. | international cooperation in arbovirus research became increasingly prominent shortly after it was found in the early 1940's, that antigenic relationships existed among certain viruses isolated in different areas of thw world. the interest of a number of scientists and of a private organization led to the establishment of an international information exchange and to the preparation of an international catalogue of arboviruses including certain other viruses of vertebrates. international cooperat ... | 1975 | 173936 |
| arboviruses in birds captured in slovakia. | virus neutralizing (vn) antibodies against sindbis, tick-borne encephalitis (tbe), west nile (wn), tahyna and calovo viruses were found in birds captured in slovakia. in parallel, sindbis, tbe and wn viruses were isolated from the blood, brain and liver of migrating birds. | 1977 | 203628 |
| biochemical studies on the phlebotomus fever group viruses (bunyaviridae family). | analyses of the virion polypeptides and genomes of several phlebotomus fever group viruses, karimabad, punta toro, chagres, and the sandfly fever sicilian serotype viruses, have established that they are biochemically similar to the accepted members of the bunyaviridae family. like snowshoe hare virus (a member of the california serogroup of the bunyavirus genus of the bunyaviridae family), karimabad, punta toro, chagres, and the sandfly fever sicilian serotype viruses all have three viral rna s ... | 1979 | 225523 |
| california encephalitis virus development in mosquitoes as revealed by transmission studies, immunoperoxidase staining, and electron microscopy. | isolates of the snowshoe hare subtype of california encephalitis (ce) virus from yukon mosquitoes during 1972 and 1973 were transmitted by bites of aedes aegypti mosquitoes after 4 to 5 weeks of extrinsic incubation at 55 degrees f after intrathoracic injection, and the 1973 strain was transmitted after mosquitoes were fed virus and held for 3 to 4 weeks at 75 degrees f. antigen of a 1971 isolate of ce virus (marsh lake 23) was detected in salivary glands of infected mosquitoes by the immunopero ... | 1975 | 235355 |
| california encephalitis virus prevalence throughout the yukon territory, 1971-1974. | california encephalitis (ce) virus (snowshoe hare subtype) was isolated from 1 of 38 pools comprising 970 unengorged female aedes canadensis mosquitoes and from 3 of 152 pools containing 5,676 a. communis mosquitoes which were collected in the yukon territory, canada between latitudes 61 and 66 degrees n during june and july 1974. during four summers 1971 through 1974, this virus was recovered from 26 of 648 pools derived from 30,686 mosquitoes of 4 species. isolation of ce virus from 1 of 109 p ... | 1975 | 239604 |
| selection for plaque variants of two california group arboviruses (jamestown canyon and la crosse) by passage in natural vertebrate hosts. | the plaque size and distribution of prototype la crosse (lac) and jamestown canyon (jc) viruses were investigated in vero cell cultures. the effect of serial passage of the viruses in their natural vertebrate hosts - the chipmunk and grey squirrel for lac and the white-tailed deer for jc virus - was studied. prototype jc virus was predominately a pinpoint plaque type (about 0.3 mm in diameter). a large plaque variant (about 1.0 mm in diameter), which was only 1 percent of prototype jc virus, inc ... | 1975 | 241230 |
| growth of tahyna virus at low temperatures. | replication of two tahyna virus strains in the aedes albopictus mosquito cell line was studied in the temperature range from 6 to 28 degrees c. the virus grew in this temperature range; its replication rate was related to the temperature of incubation. at lower temperatures the virus titres increased more slowly and did not reach as high maximum values as at higher temperatures. short increase in incubation temperature resulted in a short increase in the titre of virus previously incubated at 10 ... | 1975 | 241231 |
| influence of early passages on the character of freshly isolated strains of tahyna virus. | the plaque size, thermostability, virulence, and average lethal time of uncloned freshly isolated strains of tahyna virus were studied in the course of 3 passages in suckling mice. all of the 10 strains were in the 1st passage thermostable (indices 4 degrees/50 degrees c less than 1.0 log10) and highly virulent (indices ic/sc less than 1.0 log10). they differed significantly in plaque size only. the effect of 3 passages in suckling mice was manifested by titre increase and plaque size reduction. ... | 1975 | 241232 |
| virus neutralizing antibodies to arboviruses in birds of the order anseriformes in czechoslovakia. | sera from birds of the order anseriformes in czechoslovakia were examined for virus neutralizing (vn) antibodies to arboviruses. vn antibodies to sindbis, calovo and tahyna viruses were found in 15, 5 and 6 out of 106 greylag goose (anser anser) sera. out of 38 ducks, 6 mallards (anas platyrhynchos) and 1 garganey (anas querquedula) contained vn antibodies to sindbis virus, 6 mallards to calovo virus, 4 mallards and 1 garganey to tahyna virus, 2 mallards and 1 garganey to tick-borne encephalitis ... | 1975 | 241234 |
| isolation of tahyna virus from field collected culiseta annulata (schrk.) larvae. | | 1975 | 241252 |
| isolation of tahyna virus from the blood of sick children. | | 1975 | 241253 |
| california virus encephalitis in north carolina. | | 1978 | 281597 |
| california encephalitis virus transmission by arctic and domestic mosquitoes. | a zero passage arctic mosquito isolate of california encephalitis (ce) virus (showshoe hare subtype) was transmitted by wild-caught aedes communis mosquitoes after 13 days incubation at 13 degrees and 23 degrees c, after 20 days incubation at 13 degrees c, when mosquitoes imbibed 1 mouse ld50 in a blood meal. transmission occurred after 20 days incubation at 13 degrees and 23 degrees c when mosquitoes were injected intrathoracially with 1 or 0.1 mouse ld50. virus was also transmitted by a. aegyp ... | 1977 | 336009 |
| la crosse virus soluble cell culture antigen. | a virus-free soluble antigen, obtained by ammonium sulfate precipitation of the supernatant fluids of la crosse virus-infected bhk-21 cell cultures, was more reactive and more specific than infected suckling mouse brain antigen when compared by immunodiffusion and counterelectrophoresis tests. by complement fixation tests, the antigen was cross-reactive with heterologous california group arbovirus hyperimmune mouse ascitic fluids, but to a lesser degree than was the standard sucrose-acetone-extr ... | 1977 | 412862 |
| oligosaccharides of the california encephalitis viruses. | | 1979 | 442535 |
| serologic examination of human population in south moravia (czechoslovakia) on the presence of antibodies to arboviruses of the alfavirus, flavivirus, turlock groups and bunyamwera supergroup. | a statistically representative group of human population from the south moravian region (cssr) was examined on the presence of antibodies against the following arboviruses: lednice, sindbis, tick-borne encephalitis, west nile, tahyna and calovo. the ascertained absence of antibodies to the lednice virus is an evidence that at present this virus is of no epidemiological importance in the region studied. no antibodies to sindbis, west nile and calovo viruses were demonstrated. 17.8 to 42.0% of ant ... | 1979 | 447128 |
| a comparison of la crosse virus isolated obtained from different ecological niches and an analysis of the structural components of california encephalitis serogroup viruses and other bunyaviruses. | analyses of the oligonucleotide fingerprints of the three genome ribonucleic acid (rna) species of 11 isolates of la crosse (lac) virus, obtained from various ecological niches in the northern united states and compared to those of prototype lac virus, showed that in each place from which these isolates were obtained lac variants and varieties were present with related, but distinguishable, nucleotide sequences for their large, medium, or small rna species. the rna genomes of prototypes trivitta ... | 1979 | 453439 |
| investigations on the presence of antibodies to tahyna virus in romania. | serological results are presented of the hai reaction to tahyna virus performed in 1,749 apparently healthy subjects from two countries of romania where culex pipiens mosquitoes occur frequently, in 113 febrile patients (some of which exhibited signs of interstitial pneumonia) and in 675 domestic animals (swine, cattle, sheep and goats). | 1979 | 462795 |
| relationship of california group virus infection and mental retardation: seroepidemiological observations. | a plaque reduction neutralisation test was utilised to determine the prevalence of antibodies to california group virus (lacrosse subtype) among 612 moderately to profoundly retarded subjects resident in two wisconsin state institutions. neutralising antibodies were detected in the sera of fifty-one (8 per cent) of the subjects tested. age and sex differences in antibody distribution were not significant. when sero-logical data correlated with clinical case history records, antibody was found in ... | 1979 | 480342 |
| m viral rna segment of bunyaviruses codes for two glycoproteins, g1 and g2. | tryptic peptide digests of the two viral glycoproteins (g1 and g2) of snowshow hare (ssh) virus, la crosse, la crosse (lac) virus, and an ssh/lac recombinant virus which has a large (l)/medium (m)/small (s) rna segment genome composition of ssh/lac/ssh were analyzed by ion-exchange column chromatography. the analyses prove that the m rna species of bunyaviruses codes for the two viral glycoproteins. | 1979 | 480466 |
| higher venereal infection and transmission rates with la crosse virus in aedes triseriatus engorged before mating. | infection of colonized female aedes triseriatus by la crosse (lac) virus occurred more frequently when females were inseminated by infected males after the females engorged blood (49% of 39) than when mating took place before engorgement (4% of 554). salivary transmission of lac virus to mice also was more frequent in females venerally infected after engorgement on a normal mouse (35% of 34) than in females mated before engorgement (2% of 49). lac virus was transovarially transmitted by 40% of 1 ... | 1979 | 484771 |
| aedes triseriatus and la crosse virus: lack of infection in eggs of the first ovarian cycle following oral infection of females. | la crosse (lac) virus filial infection rates were 0% for 279 first ovarian cycle larvae, 43% for 380 second ovarian cycle larvae, and 58% for 363 third ovarian cycle larvae from orally infected mosquitoes representing 14 wisconsin populations of aedes triseriatus. lac virus was not detected in 72 pools representing 2,250 first ovarian cycle larvae, while 35 pools and 16 pools each containing 30 second and third ovarian cycle larvae, respectively, were all positive for lac virus. similar results ... | 1979 | 484772 |
| growth of california encephalitis and other viruses in aedes dorsalis (diptera: culicidae) cell cultures. | | 1979 | 490565 |
| recombination between snowhoe hare and la crosse bunyaviruses. | we have previously reported heterologous genetic recombination resulting from crosses involving temperature-sensitive (ts) mutants of la crosse (lac) group ii and snowshoe hare (ssh) group i ts mutants (j. gentsch, l. r. wynne, j. p. clewley, r. e. shope, and d. h. l. bishop, j. virol. 24:893-902, 1977). from those crosses two reassortant viruses having the large/medium/small viral rna segment genotypes of ssh/lac/ssh and ssh/lac/lac were obtained. in this study it has been found that the recipr ... | 1979 | 513193 |
| comparative susceptibility of ps cells, xtc-2 cells, and suckling mice to infection with california group arboviruses (bunyaviridae). | | 1979 | 531913 |
| [arbovirus infections observed in france]. | | 1979 | 545651 |
| polykaryocytosis induced by certain arboviruses in monolayers of bhk-21-528 cells. | multinucleated giant cell formation in a clone of bhk-21 cells, bhk-21-528, was tested with certain arboviruses. eleven out of 19 viruses tested, chikungunya, getah, sagiyama, sindbis, western equine encephalitis, st. louis encephalitis, japanese encephalitis, west nile, bunyamwera, germiston and california encephalitis virus induced cell fusion after infection. all cases where giant cells were observed during the experiments, involved the b type cell fusion (fusion from within). | 1977 | 557074 |
| three unique viral rna species of snowshoe hare and la crosse bunyaviruses. | two-dimensional gel electrophoreses of rnase t1-derived oligonucleotides of the three individual rna segments of the bunyavirus snowshow hare virus indicate that its three rna segments possess distinct nucleotide sequences. the fingerprints of the rna species of snowshoe hare virus differ from those of the antigenically closely related la crosse virus. three viral rna species have been identified in preparations of melao and trivittatus as well as snowshoe hare, lumbo, and la crosse bunyaviruses ... | 1977 | 559104 |
| formation of recombinants between snowshoe hare and la crosse bunyaviruses. | wild-type recombinants were obtained at high frequency from coinfections of bhk cells involving temperature-sensitive, conditional-lethal mutants of snowshoe hare (ssh) and la crosse (lac) bunyaviruses. analyses of two of the recombinants indicated that they have the genome compositions ssh/lac/ssh and ssh/lac/lac for their respective l, m, and s virion rna species. this evidence, together with that for the genetic stability of the recombinants, indicates that they were derived by segment reasso ... | 1977 | 592468 |
| experimental infection of foxes with tahyna virus. | three foxes about 18 weeks old were each subcutaneously inoculated with approximately 200 ld50 dose of extraneurally passaged strain of the tahyna virus "236". viremia was demonstrated in all animals during the 48-96 hours interval after infection. the maximum value was 1.31 dex ld50/0.02 ml. three weeks after infection a seroconversion was revealed by means of hemagglutination-inhibition test (from titre less than 1 : 10 to 1 : 320) and plaque-reduction neutralization test (from titre less than ... | 1977 | 604220 |
| vertical transmission of la crosse virus (california encephalitis group): transovarial and filial infection rates in aedes triseriatus (diptera: culicidae). | | 1977 | 609074 |
| isolation and preliminary characterization of temperature-sensitive mutants of lumbo virus. | | 1978 | 619489 |
| laboratory studies of transovarial transmission of trivittatus virus by aedes trivittatus. | aedes trivittatus were experimentally exposed through a membrane to a concentration of trivittatus (tvt) virus in dog defibrinated blood of 10(3.4)-10(3.5) smicld 50/0.025 ml. transovarial and transstadial transmission was demonstrated. fifty-five percent of the infected mosquitoes tested transovarially transmitted tvt virus. tvt virus was isolated from 16% of the f1 generation progeny examined, including 19% of the larvae, 23% of adult females, and 10% of adult males. | 1978 | 626271 |
| venereal transmission of la crosse virus from male to female aedes triseriatus. | horizontal transmission of la crosse (lac) arbovirus in colonized aedes triseriatus was first observed in mating cages. lac antigen was visualized by fluorescent antibody technique in multiple organs of 5 (2.5% of 198 females dissected after contact in mating cages with males, with a transovarial infection rate of 31%. venereal transmission of lac virus was demonstrated by limited contact induced mating. antigen was detected in bursal contents of 35 (53%) of 66 females dissected within 24 h afte ... | 1978 | 626272 |
| towards a quantitative understanding of the epidemiology of keystone virus in the eastern united states. | the implications of the keystone virus--aedes atlanticus transmission cycle are explored in the context of a quantitative model. among the variables considered are the vertical transmission rate, the effect of the virus upon vector fertility and survival, vector densities and distributions, the proportion susceptible in the vertebrate population, the attractiveness of different vertebrates to the vector and vector survival rates. the logical relationships between these several variables are expl ... | 1978 | 646025 |
| diagnosis of california la crosse virus infection by counterimmunoelectrophoresis. | la crosse virus cell culture-derived soluble antigen was used in a counterimmunoelectrophoresis procedure to assess the presence or absence of la crosse antibodies in 79 paired acute- and convalescent-phase human sera. the counterimmunoelectrophoresis test appeared to measure the same antibody as the complement fixation test but was more sensitive and rapid. | 1978 | 670382 |
| [experimental infection of ades caspius caspius pall. mosquitoes with the tahyna virus]. | | 1978 | 672780 |
| antibodies to snowshoe hare virus of the california group in the snowshoe hare (lepus americanus) population of nova scotia. | serological study showed the presence of antibodies to snowshoe hare virus in 6--14% of snowshoe hares (lepus americanus) samples in nova scotia. this report extends the known range of this virus in north america. | 1978 | 686253 |
| natural transmission of keystone virus to sentinel rabbits on the delmarva peninsula. | domestic rabbits were exposed in the pocomoke cypress swamp from early may through october 1973, to act as sentinel indicators of keystone (key) virus transmission on the delaware-maryland-virginia (delmarva) peninsula. rabbits were bled weekly and their sera were tested for the presence of neutralizing antibody to both key and james-town canyon (jc) viruses. adult mosquito activity was monitored concurrently by cdc miniature light traps with dry ice. of 100 rabbits exposed, 20 rabbits acquired ... | 1978 | 717629 |
| delineation of la crosse virus in developmental stages of transovarially infected aedes triseriatus. | the tropisms and development of la crosse (lac) virus in stages of transovarially infected aedes triseriatus were studied with fluorescent antibody (fa) stained dissected organs and titrations of individual arthropods in suckling mice. viral antigen was detected by fa in 95 of 387 dissected larvae, pupae, and adults. in larvae highest levels of fluorescence were detected in the alimentary tract, followed by ganglia, malpighian tubule, muscle, and other tissues. no specific organs or germ layer-d ... | 1976 | 779503 |
| [clinical and epidemiologic significance of arboviruses in central europe]. | | 1976 | 794666 |
| isolates of california encephalitis (la crosse) virus from field-collected eggs and larvae of aedes triseriatus: identification of the overwintering site of california encephalitis. | california encephalitis is caused primarily by la crosse virus, a mosquito-borne agent of which the vector is the mosquito aedes triseriatus. once la crosse virus has been detected in a given geographical area, observations in the same area during subsequent seasons usually have revealed continuing presence of the virus. field studies were conducted around the homes of children who had had california encephalitis in an effort to define the mechanism by which the virus survived the winter. eggs a ... | 1975 | 805813 |
| california encephalitis virus: some biological and biochemical properties. | | 1977 | 835232 |
| natural foci of california encephalitis virus activity in the yukon territory. | | 1977 | 849577 |
| venereal transmission of la crosse (california encephalitis) arbovirus in aedes triseriatus mosquitoes. | veneral transmission of la crosse virus by males of aedes triseriatus was demonstrated. la crosse virus was detected in the bursa of females after induced copulation, and disseminated infection was shown to occur occasionally. since males of aedes triseriatus have transovarial filial infection rates similar to those of females and can repeatedly mate, veneral transmission may be an important supplement to other natural endemic maintenance mechanisms. | 1977 | 850794 |
| electron microscopy of the segmented rna genome ofla crosse virus: absence of circular molecules. | the three species of single-stranded rna present in la crosse virus were examined in the electron microscope. because large amounts of contaminating cellular dna are copurified with the virus despite extensive attempts to purify the virus, it was necessary to use procedures that eliminated the bulk of this dna before the viral rna was analyzed. when this was done, the modal lengths of la crosse virus rna were 0.4, 2.0, and 3.1 mum. these lengths correspond well to their known molecular weights o ... | 1977 | 853565 |
| single inoculation immune hamster sera for typing california group arboviruses by the complement-fixation test. | eight reference california group viruses of north america were typed using sera of immune hamsters bled 21 days after a single inoculation. the complement-fixation test reactions were relatively specific, although only 2-fold differences were observed reciprocally with the closely-related la crosse and snowshoe hare viruses. hamster serum taken 10 days post inoculation was more specific than a 21-day serum. sepcificity after second inoculation was lost with some antigens. jamestown canyon and so ... | 1977 | 869106 |
| two more mosquito species proved as vectors of tahyna virus in czechoslovakia. | two strains of tahyna virus were isolated during mosquito virological testing in summer 1975 in the littoral zone of large fishponds in south moravia. the first of them was isolated from culex modestus mosquito, the other one from aedes sticticus. virus isolation from these species proved them to be vectors of tahyna virus, as it was found already experimentally that tahyăn virus multiplies in these mosquitoes. this virus was isolated from the two species for the first time in central europe and ... | 1977 | 881145 |
| isolation of trivittatus virus from larvae and adults reared from field-collected larvae of aedes trivittatus (diptera: culicidae). | | 1977 | 886560 |
| viremia and antibody response to la crosse virus in sentinel gray squirrels (sciuris carolinensis) and chipmunks tamias striatus). | six isolates of la crosse (lac) virus were obtained from sentinel gray squirrels (sciuris carolinensis) and four from sentinel chipmunks (tamias striatus) in an endemic area. viremia titers were measured by plaquing on vero cells. antibody responses of the animals were measured by a microneutralization test employing four california group viruses: lac, snowshoe hare (ssh), trivittatus, and jamestown canyon. in both species lac antibody titers peaked at approximately 21 days and were still detect ... | 1977 | 889022 |
| aedes triseriatus and la crosse virus: geographic variation in vector susceptibility and ability to transmit. | in laboratory tests, 20 strains of aedes triseriatus differed widely in response to la crosse virus. infection rates ranged from 40% to 93%, and rate of transmission ranged from 20% to 90%. a control strain, tested in seven different trials, showed no significant variation in susceptibility (71--77%) or transmission ability (54--68%). a distinct geographic pattern was evident. the susceptibility and transmission rates of strains from areas where la crosse virus is endemic were lower than that of ... | 1977 | 907059 |
| [acute infections induced by tahyna virus, evaluation of the years 1959--1976 (author's transl)]. | | 1977 | 908056 |
| california encephalitis virus proliferation in yukon mosquitoes incubated at low temperatures. | replication of a subarctic bunyavirus, california encephalitis (snowshoe hare subtype), was detected in salivary glands and thoraces of wild-caught aedes communis mosquitoes from the yokon territory, after intrathoracic inoculation with 0.1 to 100 mouse ld50 virus, and incubation for 7 to 21 days throughout their viable temperature range of 0 to 23 degrees c. immunoperoxidase staining confirmed that viral replication occurred in the cytoplasm of acinar cells of salivary glands, both by ligh micr ... | 1976 | 963625 |
| structural proteins of la crosse virus. | preparations of la crosse virus, a member of the california encephalitis group of bunyaviruses, were found to possess three major virion proteins. two of the proteins were glycosylated (g1 and g2) and were located on the surface of the virus particles. these two glycoproteins were present in equimolar amounts and possessed apparent molecular weights of 120 x 10(3) and 34 x 10(3). virion nucleocapsids, isolated by a nonionic detergent and salt treatment, contained another major protein, n (molecu ... | 1976 | 972436 |
| segmented genome and nucleocapsid of la crosse virus. | la crosse (lac) virions purified by velocity and equilibrium gradient centrifugation contained three single-stranded rna species. the three segments had sedimentation coefficients of 31s, 25s, and 12s by sodium dodecyl sulfate-sucrose gradient centrifugation. by comparison with other viral and cellular rna species, the lac viral rnas had molecular weights of 2.9 x 10(6), 1.8 x 10(6), and 0.4 x 10(6). phenol-sodium dodecyl sulfate-extracted lac virion rna was not infectious for bhk-21 cell cultur ... | 1976 | 994302 |
| serum dilution neutralization test for california group virus identification and serology. | the serum dilution neutralization test was evaluated for serological diagnosis of california group arbovirus infections and identification of virus isolates. the technical advantages and the degree of subtype specificity of the serum dilution neutralization test over the hemagglutination inhibition test and the complement fixation test were demonstrated with paired specimens from human cases, single human survey sera, and sentinel rabbit sera. twenty-one virus isolates from various geographical ... | 1976 | 1002829 |
| dynamics of the natural focus of tahyna virus in southern moravia and species succession of its vectors, the mosquitoes of the genus aedes. | the paper deals with the occurrence of aedes mosquitoes in southern moravia and with tahyna virus infection rates for them in 1972; a comparison of the data from previous years reveals the dynamics of the natural focus under long-term study. a total of 13,204 mosquitoes of the genus aedes was processed in 122 tests, resulting in 17 tahyna virus strains isolates. as concerns the valence of the natural focus, the most important was the inundated forest in the drnholec locality. infection rates for ... | 1976 | 1010493 |
| [isolation of tahyna virus from the blood of sick children]. | | 1976 | 1017053 |
| transovarial transmission of lacrosse virus in aedes triseriatus. | as part of a continuing investigation on the ecology of lacrosse virus in wisconsin, field and laboratory studies were conducted to explore the possibility that the virus is transmitted transovarially in a. triseriatus mosquitoes. in laboratory experiments, a. triseriatus mosquitoes were infected by ingesting lacrosse virus in defibrinated blood. lacrosse virus was recovered from f1 eggs, larvae, and adults that originated from the infected parent mosquitoes. in a subsequent field study aimed at ... | 1975 | 1072592 |
| emergence of la crosse virus from endemic foci. fluorescent antibody studies of overwintered aedes triseriatus. | the frequency and distribution of la crosse (lac) virus overwintering in aedes triseriatus diapause eggs were studied during 1974 by following 64 tree-hole oviposition sites in four enzootic hardwood forest areas. a direct fluorescent antibody technique, adapted for detection of lac virus in individual mosquitoes, proved to be a rapid, reliable and economical tool for ascertaining true field infection rates. virus was found in larvae from each of the four study areas before the seasonal emergenc ... | 1975 | 1098500 |
| serological diagnosis of california (la crosse) encephalitis by immunofluorescence. | a method of indirect immunofluorescence was developed and examined retrospectively as a serological test for the laboratory diagnosis of california encephalitis (ce). lacrosse virus immunofluorescence immunoglobulin (ig) g and igm studies were done on paired sera from 50 patients with acute central nervous system infections. ce had been documented in 25 patients by hemagglutination inhibition, neutralizing, complement fixing, and/or precipitin tests. five (20%) of the acute and 16 (64%) of the c ... | 1975 | 1100666 |
| the role of mammals in the circulation of tahyna virus. | | 1975 | 1104418 |
| isolation of la crosse virus (california encephalitis group) from the chipmunk (tamias striatus), an amplifier host. | la crosse (lac) virus was isolated from the blood of seven chipmunks (tamias striatus) captured during the summer of 1970 in southwestern wisconsin. with the exception of the original isolate obtained from human brain after fatal encephalitis, these represent the first known isolations of lac virus from a naturally infected free-living vertebrate. the chipmunks were trapped and periodically recaptured in two study areas where 59 chipmunks became infected and developed neutralizing antibody durin ... | 1975 | 1106233 |
| isolations of california encephalitis virus from tundra mosquitoes. | | 1975 | 1122430 |
| arbovirus surveillance in florida: wild vertebrate studies 1965-1974. | wildlife species from 38 of florida's 67 counties were surveyed over a 10 year period for the presence of antibody to the five major arboviruses circulating in the state. the routine screening of 7891 sera from wild birds and mammals via the hemagglutination-inhibition (h1) test with selected reactors subjected to serum neutralization testing has 1) provided information regarding geographic distribution and seasonality of circulation of these viruses 2) identified enzootic foci of infection and ... | 1975 | 1152173 |
| laboratory studies of transovarial transmission of la crosse and other arboviruses by aedes albopictus and culex fatigans. | transovarial transmission of la crosse virus by experimentally infected aedes albopictus females to 2.7% of their f1 generation offspring was demonstrated. progeny of both sexes were infected. mean virus titers in parent mosquitoes and infected f1 generation adults were 10(4.6) and 10(3.4) plaque forming units/insect, respectively. the la crosse-infected offspring were randomly distributed among the female parents. after two serial passages in a. albopictus, a marked change occurred in the plaqu ... | 1975 | 1190373 |
| host preferences of aedes trivittatus (diptera: culicidae) in central iowa. | the vertebrate host preferences of aedes trivittatus mosquitoes were studied to gain an insight into the possible hosts of trivittatus (tvt) virus (california encephalitis group) in iowa. engorged mosquitoes were collected with a malaise trap and dry ice-baited cdc miniature light traps. the origin of mosquito blood meals was determined by the capillary tube precipitin test. of 600 a. trivittatus blood meals tested, 409 (68.2%) reacted positively with anti-rabbit serum. the incidences of mosquit ... | 1975 | 1190374 |
| aedes hendersoni: failure of laboratory-infected mosquitoes to transmit lacrosse virus (california encephalitis group). | | 1975 | 1195294 |
| trivittatus virus infections in wild mammals and sentinel rabbits in central iowa. | a serological survey was conducted in iowa to determine the prevalence rate of california group virus antibodies in sera of several vertebrate species. serum specimens were assayed for infectivity-neutralizing antibody in a microneutralization system with baby hamster kidney cell culture. of 77 sera assayed, 21 (27%) neutralized trivittatus (tvt) virus infectivity. the antibody prevalence rate was highest for eastern cottontail rabbits inasmuch as 46% (10/22) of the serum specimens form this spe ... | 1975 | 1200251 |