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infection of bovine fetuses at 120 days' gestation with virulent and avirulent strains of bluetongue virus serotype 11.bluetongue virus infection in sheep and cattle during fetal development causes neuropathology. two strains of bluetongue virus serotype 11 designated as uc-2 and uc-8 have different virulence patterns in newborn mice. these viruses have distinctly different electropherotype patterns on polyacrylamide gel electrophoresis indicating a genetic difference in these two viruses of the same serotype. four bovine fetuses each were inoculated intramuscularly with either uc-2 or uc-8, and one fetus was in ...19921312421
complete genomic sequences of the gp5 protein gene of bluetongue virus serotype 11 and 17.the complete nucleotide sequences of full-length copies of genomic segment 6 or m3 of us bluetongue virus serotype 11 and 17 consisted of 1638 nucleotides. the plus-strand contained an open reading frame for a protein of 526 amino acids which was equivalent to about 59,000 da, similar to the molecular weight of gp5 as determined by sds-page analysis. this long open reading frame was flanked by a 5' non-coding region of 29 nucleotides and a 3' non-coding region of 28 bases. when the predicted ami ...19921318625
association of virulent and avirulent strains of bluetongue virus serotype 11 with premature births of late-term bovine fetuses.two strains of bluetongue virus serotype 11 (btv 11), uc-2 avirulent and uc-8 neurovirulent in newborn mice, were inoculated into late-term bovine fetuses to investigate whether infection with these two btv strains in late gestation would produce congenital infection and pathological changes. fetuses were inoculated by intramuscular injection through the uterine wall at 243 days gestation and recovered after spontaneous delivery. in calves inoculated with uc-8, births occurred 15 to 27 days befo ...19921322944
complete nucleotide and deduced amino acid sequence of genome segment 5 encoding the outer capsid protein, vp5, of a u.s. isolate of bluetongue virus serotype 11.the complete nucleotide sequence of the rna genome segment coding for the outer capsid protein, vp5, of the united states prototypic strain of bluetongue virus (btv) serotype 11 was determined from two overlapping cdna clones. the genome segment was found to be 1638 nucleotides in length with a single open reading frame coding for a 526 amino acid protein of mw 59,278 and having a net charge of -4.0 at neutral ph. comparisons of the predicted amino acid sequence of vp5 of btv 11 with those of th ...19911661982
failure to establish congenital bluetongue virus infection by infecting cows in early pregnancy.two groups of 10 pregnant cows were inoculated with bluetongue virus type 11 at either 40 or 60 days of gestation. all the cows became infected as judged by the detection of viraemia and seroconversion but they showed no clinical signs. seventeen of the cows produced live calves none of which showed any evidence of prenatal infection. after challenge with the same virus all the calves became viraemic and seroconverted. the response to challenge of the two groups did not differ from that of a con ...19911852081
identification of genetic variation between strains of bluetongue virus serotype 11 using cdna probes.recombinant plasmids containing inserts representing genome segments 2, 5, 6, 8, and 9 of bluetongue virus (btv) serotype 11, with tentative coding assignments for viral proteins p2, p5, ns1, ns2, and p6, respectively, have been used to study the genetic diversity within a btv serotype using northern blot hybridization. btv 11 strains were isolated in california, nevada, oklahoma, and mexico from elk, deer, and cattle. diversity was indirectly indicated in the btv 11 strains by comparisons of el ...19892543132
molecular cloning of serogroup- and serotype-specific genome segments from bluetongue virus serotype 11.genome segments 2, 6, 8, and 9 of bluetongue virus (btv) serotype 11, coding for p2, ns1, ns2, and p6, respectively, were cloned into puc 8. sizes of segment-2 and segment-6 clones indicated partial copies (55% and 80% of full length, respectively), whereas segment 8 and 9 clones represented full-length copies. northern blot hybridizations of the clones to the 5 united states btv prototypic serotypes (2, 10, 11, 13, and 17) revealed segment-2 clone to be serotype-specific to btv-11, whereas segm ...19892552873
neurovirulence of the uc-2 and uc-8 strains of bluetongue virus serotype 11 in newborn mice.in vivo and in vitro experiments were done to investigate whether the difference in neurovirulence between the two strains of bluetongue virus 11, uc-2 and uc-8, is based on a different capability to gain access to the brain from the subcutaneous inoculation site or on a different tropism for neural cells. in newborn balb/c mice subcutaneous inoculation of uc-8 at doses between 10(-0.2) plaque forming units (pfu) and 10(4.8) pfu caused a severe necrotizing encephalitis whereas uc-2 at doses of u ...19872823445
genetic reassortment of bluetongue virus serotype 11 strains in the bovine.reassortants of bluetongue virus serotype 11 (btv-11) were isolated from a yearling heifer experimentally infected with two electrophoretically different strains (uc-2 and uc-8) by subcutaneous inoculation. viruses were recovered by direct titration of sonicated blood samples onto vero cell monolayers, which were overlaid with agarose and later plaque purified. the parental electropherotype of uc-8 was identified as the predominant virus strain during the infection; uc-2 was not isolated. uc-2 i ...19872830703
strain-dependent virulence characteristics of bluetongue virus serotype 11.two strains of bluetongue virus (btv) serotype 11, uc-2 and uc-8, were identified by the electrophoretic migration pattern of their genomic rna segments on polyacrylamide gel electrophoresis. significant differences in virulence of these two viruses could be demonstrated by subcutaneous inoculation of newborn mice. no signs of disease were observed in mice infected with uc-2. mice infected with uc-8 died of a severe necrotizing encephalitis, which resembled lesions in bovine and ovine foetuses i ...19863007664
genetic variation of bluetongue virus serotype 11 isolated from host (sheep) and vector (culicoides variipennis) at the same site.genetic relatedness of 2 strains of bluetongue virus (btv) serotype 11 that were isolated from the same geographic site--one from host (sheep) and the other from the vector culicoides variipennis during an enzootic of bluetongue at bruneau, idaho, in august 1973--was determined by comparing the oligonucleotide fingerprint analyses of the individual double-stranded rna segments of the genomes. it was observed that the 2 strains of btv-11 exhibit considerable differences in their genotypes, the pe ...19836307090
growth of a neuroinvasive strain of bluetongue virus in suckling mice.some strains of bluetongue virus cause congenital brain damage in bovine and ovine fetuses, as well as in neonatal mice. two strains of bluetongue virus serotype 11 (uc-2 and uc-8) which differ in neuroinvasiveness were used to determine the biological basis for this difference. uc-2 and uc-8 were inoculated subcutaneously into newborn mice and virus was titrated from blood, plasma and brain tissues over 14 days. for the invasive uc-8 strain, 50-175 plaque forming units of virus per ml was found ...19957605202
effects of temperature on virogenesis of bluetongue virus serotype 11 in culicoides variipennis sonorensis.culicoides variipennis sonorensis females were fed bluetongue virus serotype 11 mixed in sheep blood and were held at constant temperatures of 32, 27, 21 and 15 degrees c. virogenesis, as measured by enzyme-linked immunosorbent assay (elisa), proceeded significantly faster at higher temperatures. based on elisa absorbance > or = 0.2, some flies first were categorized as infected after 1 day, 2 days and 4 days at 32, 27 and 21 degrees c, respectively. peak levels of virus antigen were seen after ...19957696691
experimentally induced infection with bluetongue virus serotype 11 in cows.the consequences of inoculation of bluetongue virus (btv) serotype 11 into 16 susceptible cows either at the time of breeding or at specified stages of pregnancy were studied. the cows were free of btv or epizootic hemorrhagic disease virus, and none had antibodies to btv before virus inoculation. a group of 4 cows was mated naturally to a bull reported to shed btv-11 (co75b300 strain) in the semen. the bull was suspected of infecting cows at mating with btv-11, which subsequently transplacental ...19947879975
experimental infection of pregnant cattle with bluetongue virus serotype 11 between postbreeding days 21 and 48.four bluetongue virus (btv)-seronegative heifers and 2 btv-seropositive heifers were inoculated with the virulent strain uc-8 of btv-11 between postbreeding days (pbd) 21 and 30. the heifers were observed for 10-18 days after inoculation for clinical signs, and pregnancy was monitored by ultrasound examination of the uterus and by plasma progesterone levels. blood samples were collected daily after inoculation and processed for virus isolation and titration. heifers were euthanized between pbd 3 ...19938396981
the role of cell-mediated immunity in the pathogenesis of bluetongue virus serotype 11 in the experimental infection of vaccine/sensitized calves.the cellular immune response of cattle to virulent and avirulent (inactivated) bluetongue virus (btv) was studied. each of three calves received three vaccinations (sensitizations) with binary ethyleneimine (bei)-inactivated btv, 3 weeks apart. the sensitized animals were challenged with btv-11 strain uc8 3 weeks after the last vaccination. btv-seropositive and btv-seronegative calves were used as controls. the animals were bled weekly for virus isolation and for evidence of cell-mediated immuni ...19979280389
histamine and eicosanoid levels in plasma and peripheral blood leucocyte cultures during experimental infection of cattle with bluetongue virus serotype 11.three calves were sensitized with three doses of inactivated btv-11 uc8 strain and then experimentally infected with the homologous virus. in addition, four btv-seronegative heifers were also experimentally infected with btv-11. granulocyte rich fractions of peripheral blood leucocyte (pbl-grf) cultures from btv-sensitized/infected calves and from control unexposed cattle were exposed in vitro with btv-11. histamine, leukotriene (lt) c4 and prostaglandin (pg) d2 were assayed in supernatant fluid ...19979394610
molecular epidemiology of bluetongue virus in northern colorado.the molecular epidemiology of bluetongue virus serotype 11 (btv11) in an enzootic focus in northern colorado was investigated. viruses isolated up to 12 years apart, from both vertebrate and invertebrate hosts, were compared by phylogenetic analysis of nucleotide sequence data from three genome segments: l2, s7, and s10. for each segment, viruses isolated from ruminants in the 1980s were more similar to one another than to viruses isolated from culicoides spp. insects in the 1990s. nearly identi ...200616337708
british columbia. incursion of bluetongue virus type 11 and epizootic hemorrhagic disease of deer type 2 for two consecutive years in the okanagan valley. 198917423299
possible introduction of epizootic hemorrhagic disease of deer virus (serotype 2) and bluetongue virus (serotype 11) into british columbia in 1987 and 1988 by infected culicoides carried on the wind.outbreaks of epizootic hemorrhagic disease of deer and of bluetongue began in british columbia in august and october 1987 respectively and recrudescence of infection by both viruses was detected the following year in august. weather records for up to 18 days before the initial outbreaks of disease, isolation of virus or seroconversion were examined to determine if the viruses could have been introduced by infected culicoides carried on the wind. data on temperature, rainfall, wind speed and dire ...19911665099
isolation and identification of a variant of bluetongue virus serotype 11 from a ram in a bluetongue outbreak in western texas.a field strain of bluetongue virus was isolated from a blood sample of a ram during an outbreak of bluetongue in november 1985 in western texas. in this bluetongue outbreak at least 25 of the 2,000 sheep were infected. isolation was made by intravenous inoculation of 11-day-old embryonated chicken eggs. the serotype was identified as serotype 11 by serum neutralization tests. the genomic pattern on sodium dodecyl sulfate (sds)-polyacrylamide gel electrophoresis (page) of the new isolate is simil ...19911653269
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