| equine viral encephalitis. | the most important neurotropic viral infections of the horse are the arthropod-borne encephalitides. these include venezuelan encephalitis (ve), eastern encephalitis (ee) and western encephalitis (we), which are found in the americas, and japanese b encephalitis which occurs in the far east. all the viruses cause encephalitis in man. between 1969 and 1972 an epidemic of ve occurred in central america. in 1971 the disease was reported in texas, where it was brought under control by the vaccinatio ... | 1976 | 4301 |
| ribonucleic acid polymerase activity associated with purified calf rotavirus. | the presence of an rna-dependent rna polymerase is demonstrated in purified rotavirus particles. optimum polymerase activity was found between 45 to 50 degrees c, at ph 8, and in the presence of 10 mm-magnesium ions. the polymerase product was highly sensitive to pancreatic rnase (97%) in low or high salt concentration. the enzyme was activated by edta treatment of intact particles or heat shock. the similarities between reovirus, blue-tongue virus and rotavirus polymerases are discussed. | 1977 | 21225 |
| factors affecting the bluetongue virus neutralizing antibody response and the reaction between virus and antibody. | a study was made of different aspects of the bluetongue virus neutralizing antibody response and the reaction between the virus and antibody. optimum neutralization was obtained in a 2mm tris-hcl buffer, ph 9,0, at a temperature of 4 degrees c. the reaction of virus and antibody could be demonstrated by electron microscopy in the formation of clumps which were shown to be serotype specific. it was found that both igm and igg antibodies can neutralize the virus, but that igm reached its maximum l ... | 1979 | 45124 |
| infectious bursal disease agent: morphology by negative stain electron microscopy. | the virus of infectious bursal disease of chickens was studied by immune electron microscopy. negatively-stained preparations revealed morphological similarities with both the bluetongue virus group, and the virus of infectious pancreatic necrosis of trout. results indicated that the small particle found in such preparations is a degradation product of the large particle. | 1975 | 50057 |
| antigenic and morphologic comparisons of ibaraki and bluetongue viruses. | bluetongue disease virus, type 10, and ibaraki disease virus, which causes a bluetongue-like disease of cattle, were compared to determine whether they are the same or different viruses. they were similar in morphology, but neutralization tests, complement-fixation tests, and ferritin tagging indicated that they have antigenic differences. therefore, they should be considered as different viruses. two other viruses of this group, african horsesickness and equine encephalosis, were included to sh ... | 1975 | 56211 |
| [information transfer in the biosphere and possible evolutionary significance of this process]. | | 1976 | 58493 |
| antigenic properties of human lymphoblastoid interferons. | most virus-induced human lymphoblastoid interferons examined contained variable proportions of the le and f antigenic species described for human leukocyte interferon. the f species was not detectable in interferons liberated spontaneously from human lymphoblastoid cells in culture. lymphoblastoid interferons differed considerably in their interaction with the same anti-interferon serum. spontaneous interferons required approximately ten times less antibody for neutralization than interferon ind ... | 1979 | 84793 |
| an experimental inactivated vaccine against bluetongue. | bluetongue virus grown in bhk cells was shown to be inactivated in concentrations of betapropiolactone (bpl) higher than 0-15 per cent. when the virus, inactivated with 0-2 per cent bpl and prepared as a double emulsion vaccine, was injected into cypriot sheep, no untoward reactions were observed and neutralising antibodies developed. the antibody titre reached a high level and persisted for at least a year. after re-vaccination, a secondary response was observed. a bivalent vaccine elicited a ... | 1975 | 165609 |
| bluetongue in sheep and goats. | a description is given of the symptomatology, pathology and pathogenesis of bluetongue in sheep and goats. the economic significance of the disease in south africa is discussed. | 1975 | 169785 |
| bluetongue: the disease in cattle. | most researchers in south africa found that although bt virus could be isolated from apparently healthy cattle and from inoculated cattle the virus did not produce overt clinical disease in cattle. however, when epizootics were reported outside africa, clinical signs were observed in cattle in israel, palestine, syria, portugal, and spain. most natural bt infections in cattle in the united states do not result in overt clinical signs. however, in certain infected herds, approximately 5% of the c ... | 1975 | 169786 |
| bluetongue-like disease of deer. | a comparison has been made of the disease produced in white-tailed deer by the viruses of epizootic haemorrhagic disease and bluetongue. the similar nature of these diseases in deer and of some of the viral properties has been described. although these two viruses are considered to be distinct, it is possible by employing an unnatural procedure to produce antibody which will demonstrate a minor antigenic component common to both viruses. biological features that differ between the two viruses ha ... | 1975 | 169787 |
| ibaraki disease and its relationship to bluetongue. | ibaraki disease, an epizootic disease of cattle in japan resembling bluetongue, is characterized by fever and lesions affecting the mucous membranes, the skin, the musculature and vascular system. degeneration of striated muscular tissue is observed in the oesophagus, larynx, pharynx, tongue and the skeletal muscles. oedema and haemorrhage are marked in the mouth, lips, abomasum, around the coronets, etc., and are occasionally followed by degeneration of the epithelium leading to erosions or ulc ... | 1975 | 169788 |
| serological methods in the diagnosis of bluetongue. | the viral antibodies in the serum of cattle, sheep and deer are not detectable in the ordinary direct cf test. we have shown that the so-called "non complement-fixing" viral antibodies in the serum of these animal species can be demonstrated by the mdcf test. the mdcf test, as well as the micro agp test, are group reactive, with all bt isolates studied. however, it is possible with these tests to differentiate antigenically bt virus from ehd virus. the fat was also useful in differentiating bt v ... | 1975 | 169789 |
| the comparative sensitivity of sheep and chicken embryos to bluetongue virus and observations on viraemia in experimentally infected sheep. | the virus titre in sheep blood samples received from bt-suspected cases in the field was assayed in sheep and in chicken embryos. these infected blood samples represented 3 different bt virus types: 4, 10 and 16. three identical experiments were performed, one with each of the 3 different virus types. ten-fold dilutions of the infected blood samples were prepared and 1 ml of each blood dilution was inoculated iv into series of 10 to 12-month old susceptible sheep; at the same time 0.1 ml of each ... | 1975 | 169790 |
| the epizootiology of bluetongue: the african situation. | bluetongue virus is transmitted biologically by various species of culicoides, notably c. pallidipennis and c. variipennis. factors such as rainfall, temperature and relative altitude, which influence the breeding of the insect vectors also govern the incidence and distribution of the disease. the host range of bluetongue virus includes sheep, cattle, goats and various antelopes. many other, as yet unidentified hosts could perhaps harbour the virus and influence the epizootiology of the disease. ... | 1975 | 169791 |
| bluetongue in cyprus. | | 1975 | 169792 |
| epizootiology of bluetongue: the situation in the united states of america. | bluetongue was first reported in the united states in 1948 in sheep in texas. the virus has now been isolated from sheep in 19 states. when the disease first occurs in a flock, the morbidity may reach 50 to 75% and mortality 20 to 50%. in subsequent years, the morbidity may be only 1 to 2% with very few deaths. difference in breed susceptibility has not been observed. natural bluetongue infection has not been observed in angora or dairy goats. bluetongue virus was first isolated from cattle, in ... | 1975 | 169793 |
| the control of bluetongue in an enzootic situation. | on account of the wide host range of bluetongue virus and its biological transmission by insects, control of the disease in an enzootic situation is based primarily on the active immunisation of susceptible animals as well as on the prevention of contact between the insect vectors and the susceptible hosts. in spite of their unquestionable value, the egg attenuated vaccines which are currently employed for prophylactic immunisation, have certain shortcomings. the existence of 16 known serotypes ... | 1975 | 169794 |
| certification of ruminants, semen, and ova for freedom from bluetongue virus. | | 1975 | 169795 |
| bluetongue certification -- australian policy. | australian quarantine policies with respect to bt are based on regarding this disease as one of high risk and major potential economic importance to our ruminant population. there are deficiencies in our knowledge of world distribution, epidemiology and pathogenesis. there may be unknown vectors and unsuspected animal reservoir hosts. the international distribution of bt could be extending through the movements of insects or cattle. if introduced into australia, the cattle and sheep populations ... | 1975 | 169796 |
| design and construction of an apparatus for the growth of micro cell cultures on standard glass microscope slides and its application for screening large numbers of sera by the indirect fluorescent antibody technique. | a simple stainless-steel apparatus was designed to contain standard microscope slides on which were grown micro cell cultures in the form of 16 individual monolayers per slide. the application of this apparatus for the screening of serum samples by fluorescent antibody techniques is described. | 1975 | 170316 |
| improvements in the modified direct complement fixation test and its application in the detection of bluetongue antibodies in cattle and sheep sera. | in this study, improvements were made in the technique and the preparation of the antigen. it was possible to perform three extractions and elutions resulting in a soluble reactive preparation from each batch of infected mouse brain. this led to an appreciable increase in the yield of highly reactive antigen. the presence of bluetongue antibodies was not detected in 13,210 sheep sera. of the 13,486 bovine sera tested, only three questionable reactions were obtained. it was possible to determine ... | 1975 | 164994 |
| an outbreak of a hemorrhagic disease in white-tailed deer in kentucky. | in 1971, an outbreak of a hemorrhagic disease occurred in captive and free-ranging white-tailed deer (odocoileus virginianus) in mammoth cave national park, kentucky, clinical signs and gross pathological lesions were consistent with those of epizootic hemorrhagic disease and bluetongue, as were serological and histopathological findings for samples sent to other laboratories. the infection rate among the 104 captive deer was 88-92%, and that among the free-ranging park deer appeared to be simil ... | 1975 | 167205 |
| modified hemolytic plaque technique for the detection of bluetongue virus antibody-forming cells. | a hemolytic plaque assay was developed for the detection of antibody-forming cells to bluetongue virus (btv). sheep erythrocytes (srbc), onto which btv had been absorbed, served as the indicator of lysis due to the presence of btv antibody-forming cells. the ratio of btv to srbc was found to be critical for optimum hemolytic plaque formation. for routine use, 50 mul of 12% btv srbc, 0.1 ml of a spleen cell suspension, and 0.5 ml of 0.5% agarose in a balanced salt solution were mixed and plated o ... | 1976 | 178602 |
| studies with bluetongue virus in nigeria. | using an agar gel diffusion test antibody evidence indicates that bluetongue virus is widely distributed in nigeria and commonly infects cattle, sheep and goats. in a single dairy herd serological conversions were observed in both wet and dry seasons. | 1976 | 184569 |
| a serologic survey of pronghorns in alberta and saskatchewan, 1970-1972. | to determine the exposure of free-ranging pronghorns (antilocapra americana ord) to selected pathogens, serum samples were obtained from 33 live-trapped animals from southwestern saskatchewan in 1970, and from 26 and 51 animals from southeastern alberta, in 1971 and 1972, respectively. antibodies were found to the agents of parainfluenza 3, bovine virus diarrhea, eastern and western encephalomyelitis, infectious bovine rhinotracheitis and the chlamydial group. no serologic reactors were found to ... | 1975 | 167203 |
| viral replication and interferon production in fetal and adult ovine leukocytes and spleen cells. | peripheral blood leukocyte and spleen cell cultures derived from adult sheep and from third-trimester (107 to 145 days of gestation) and second-trimester (70 to 98 days of gestation) fetal lambs were examined for their ability to support viral replication and to produce interferon. bluetongue virus, herpesvirus hominis type 2, and chikungunya virus failed to replicate in either leukocyte or spleen cell cultures derived from adult ewes or in cultures from second- or third-trimester fetal lambs. s ... | 1975 | 172452 |
| a comparison of some serological tests for bluetongue virus infection. | the plaque neutralization, complement fixation, and agar gel precipitin tests were compared by measuring bluetongue virus antibody in 137 serums from experimental animals (cattle and sheep) and suspected field reactors (cattle and deer). in general, the tests agreed well with each other. plaque neutralization titers began earlier than the other two and went much higher than the complement fixation titers. plaque neutralization titers usually peaked between two and three weeks after exposure and ... | 1976 | 187301 |
| serial cyclic transmission of bluetongue virus in sheep and culicoides variipennis. | bluetongue virus (strain 62-45s) was transmitted from sheep to sheep throughout a year by vector bites. a colonized population (sonora strain, 000 line) of the biological vector culicoides variipennis (coquilllett) was used. fifteen serial cyclic transmissions covered a period of 13 months from october through november of the following year. the mean infection rate of the biting gnats was 37 percent. the clinical response to bluetongue virus was significantly more severe in sheep infected by vec ... | 1976 | 185003 |
| plaque neutralization of bluetongue virus and epizootic hemorrhagic disease virus in bhk21 cells. | plaque assay and plaque neutralization of blue-tongue virus and epizootic hemorrhagic disease virus were studied in baby hamster kidney (bhk21) cells grown under an overlay containing gum tragacanth. tests were done in plastic panels, each with 24 wells, and variables were established for achieving reproducible results. four serotypes of bluetongue virus were compared, and their antigenic differences were confirmed with this new plaque-neutralization test. | 1976 | 185929 |
| characterisation of a rotavirus.20b. | | 1975 | 173999 |
| study on the pathogenesis of bluetongue: replication of the virus in the organs of infected sheep. | the pathogenesis of bluetongue infection was studied by the titration of the virus in tissue samples taken from sheep inoculated subcutaneously in the auricula of the ear with 76 tc id50 of the plaque-purified type 10 bluetongue virus. tissue samples were taken from individual animals killed at daily intervals over a period of 11 days. the mean incubation time was 6.9 days and the first clinical sign was pyrexia. on the 4th day, bluetongue virus was demonstrated in the lymph nodes of the cephali ... | 1976 | 191775 |
| kinetics of the igm and igg immunological response to sheep erythrocytes and bluetongue virus in mice. | the igm and igg response of mice to sheep erythrocytes (srbc) and bluetongue virus (btv) was determined by means of haemolytic plaque assays. maximum primary igm response to srbc occurred after 4 days but declined rapidly to 4% of the maximum by day 9. a lag period of about 2 days was observed in the appearance of igg haemolytic plaque-forming cells (pfc) but they reached a maximum after 6-9 days. secondary immunization resulted in the stimulation particularly of igg pfc and from day 6 onwards i ... | 1976 | 191776 |
| the isolation and preliminary genetic classification of temperature-sensitive mutants of bluetongue virus. | temperature-sensitive mutants of bluetongue virus were isolated and classified in 6 genetic recombination groups. the frequency of recombination varied both within and between groups. the 4 mutagens used viz. nitrous acid, n-methyl-n-nitroso-n-nitroguanidine, proflavine and 5-fluoro-uracil were found to differ in their efficacy. the period of incubation required for maximum recombination was 48 h at 28 degrees c. | 1976 | 191777 |
| overwintering mechanism for bluetongue virus: biological recovery of latent virus from a bovine by bites of culicoides variipennis. | bluetongue virus (btv) was biologically transmitted by the bites of colonized culicoides variipennis gnats to recipient sheep from a hereford bull with latent infection. four biological recoveries of btv were mediated over 2 years by multiple feedings of the vector during a 4- to 72-hour interval. initial stimulation by gnat bites at 0 hour permitted biological recovery of btv by gnats that fed at later intervals. the 4th biological recovery of the virus from the bull clearly indicated a vector- ... | 1977 | 192095 |
| isolation and characterization of epizootic hemorrhagic disease virus from white-tailed deer (odocoileus virginianus) in eastern washington. | a virus was isolated from the spleen of a white-tailed deer (odocoileus virginianus) that had died during an epizootic in washington state in 1967. inoculation of a 10% spleen suspension from the deer caused hemorrhagic disease in normal white-tailed deer. studies were conducted on the biological, physicochemical, and serologic properties of the washington isolate. an in vitro assay system, utilizing a cultured primary of white-tailed deer fetal cells from an entire fetus, was employed for isola ... | 1977 | 192110 |
| immunoglobulin response to bluetongue virus soluble antigen in subcutaneous chambers. | group-specific antibodies were produced by inoculation of bluetongue virus soluble antigen into polyethylene chambers implanted subcutaneously in 8 rabbits and 2 sheep. for comparison, 5 rabbits and 1 sheep were inoculated intramuscularly with the soluble antigen in freund's complete adjuvant. antibodies present in the serum and chamber fluids were detected by the agar gel precipitin or serum-neutralization tests, qualitatively examined by immunoelectrophoresis and immunofluorescence, and quanti ... | 1977 | 195497 |
| isolation of bluetongue vaccine virus from infected sheep by direct inoculation onto tissue culture. | a technique is described by which the vaccine strain of bluetongue virus (btvv) may be isolated from infected fetal, neonatal, and adult sheep tissues utilizing tissue culture. the data from these studies provides evidence that 1) btvv can be readily isolated from infected fetal and newborn tissues by tissue culture, 2) mild treatment of tissues and utilization of lysed cells as inoculum an effective means of recovering vaccine virus, 3) btvv can be isolated with equal efficacy from mononuclear ... | 1977 | 188594 |
| bluetongue virus as a cause of hydranencephaly in cattle. | hydranencephaly was produced in a foetus and a calf by intra-uterine infection with an attenuated type 10 bluetongue virus. laparotomy was performed on the respective dams and the foetuses, respectively 126 days and 138 days old, were inoculated intramuscularly through the uterine wall with 1 ml of a virus suspension containing 5 x 103 tissue culture infective doese. the younger feotus was aborted on day 262, while the other one was born alive on day 273. both foetuses showed marked hydranenceph ... | 1976 | 189265 |
| double-stranded rna of ibaraki virus. | | 1977 | 190770 |
| bluetongue in cattle: effects of vector-transmitted bluetongue virus on calves previously infected in utero. | three of 7 principal calves, after a challenge of immunity exposure by bites of bluetongue (bt) virus-infected culicoides variipennis, became latently infected with bt virus. these calves were born to heifers infected with the homologous virus by bites of c variipennis at 60 or 120 days' gestation. latent bt virus infection was detected by isolation of bt virus from washed erythrocyte samples obtained from the calves at 57, 100 to 102, 200 to 202, 300 to 302, and 400 to 402 days after challenge ... | 1977 | 201193 |
| serological evidence of bluetongue in game animals in botswana. | using the agar gel precipitin technique the sera of 397 african buffalo (syncerus caffer) and 90 sera of other common game species were examined for bluetongue antibodies. of the adult buffalo 283 out of 325 (87 per cent) were positive. buffalo calves were positive in 25 out of 72 cases (35 per cent). positive reactions were also recorded in lechwe (kobus leche), tsessebe (damaliscus lunatus), red hartebeeste (alcelaphus buselaphus), gemsbok (oryx gazella), sable (hippotragus niger) and impala ( ... | 1978 | 204086 |
| relevance of laboratory colonies of the vector in arbovirus research--culicoides variipennis and bluetongue. | relevance for laboratory colonies of culicoides variipennis (coquillett) in arbovirus research was determined during colonization by comparing a vector-competence characteristic for the parent (p) field and subsequent colonized generations. three colonies established in 1972-1973 were used to determine whether each was representative of the field population from which it was derived for oral infection to 2 to 4 serotypes of bluetongue virus (btv). two colonies that were based on small numbers of ... | 1978 | 204208 |
| heterogeneity of culicoides variipennis field populations to oral infection with bluetongue virus. | a standard colonized population (000 line) of culicoides variipennis (coquillett) was used as the control for comparing the infection rate (ir) responses of different field populations of the vector to oral infection with several strains of bluetongue virus (btv) that belonged to four serotypes. three field populations from colorado and oregon tested concurrently in 1969 were differently susceptible to three btv strains representing three serotypes. the ir's of each of the three populations vari ... | 1978 | 204209 |
| bluetongue in cattle: repeated exposure of two immunologically tolerant calves to bluetongue virus by vector bites. | a heifer and steer that were immunologically tolerant to bluetongue (bt) virus became immunologically competent after repeated exposures by bites of bt virus-infected culicoides variipennis. immunologic tolerance ended in the heifer at 25 months of age, after the 2nd exposure to the virus, and in the steer at 22 months, after the 4th exposure. high hemic concentrations of bt virus were detected in both animals after they became immunologically competent, but neither developed an overt bt clinica ... | 1977 | 201194 |
| the immunological response to intact and dissociated blue-tongue virus in mice. | antigenic fractions of bluetongue virus were separated by ultracentrifugation in tris-buffered cscl gradients at ph 6, 7 or 8 and the bluetongue virus polypeptide composition of the bands isolated from these gradeints was monitored by polyacrylamide gel slab electrophoresis. the immunological response to these fractions in mice was determined by a haemolytic plaque-forming cell assay, using sheep erythrocytes onto which intact bluetongue virus was adsorbed as lytic indicator cells. isolated oute ... | 1977 | 206861 |
| susceptibility of bovine macrophage and tracheal-ring cultures to bovine viruses. | cultures of macrophages initiated from peripheral blood monocytes and organ cultures of tracheal rings were tested for their susceptibility to bovine viruses. with several notable exceptions, viruses cytopathogenic for bovine embryonic lung cultures were cytopathogenic for macrophages. although cowpox virus replicated in macrophages, pseudocowpox did not, and although pseudorabies virus replicated within macrophages, infectious bovine rhinotracheitis and dn-599 herpesviruses did not. bluetongue ... | 1977 | 201195 |
| bluetongue in cattle: effects of culicoides variipennis-transmitted bluetongue virus on pregnant heifers and their calves. | | 1977 | 201192 |
| serological evidence of the occurrence of bluetongue in iraq. | precipitating antibodies against bluetongue were detected in sheep and goat serum samples collected from animals slaughtered in baghdad abattoir. out of 294 sheep serum samples and 110 goat serum samples examined, 28 and 18 samples respectively showed precipitating activity. in addition, examination of sheep serum samples collected from localities where clinical cases similar to bluetongue were previously reported revealed the presence of bluetongue precipitating antibodies in 101 sera out of 19 ... | 1978 | 208202 |
| bluetongue virus, an exceptionally potent interferon inducer in mice. | the attenuated american bt-8 strain of bluetongue virus is 5 to 10 times more potent an interferon inducer than any other viral or nonviral agent reported to date, including as much as 600,000 units/ml of plasma by 8 h after intravenous injection. | 1978 | 208975 |
| bluetongue studies with sentinel cattle in kenya. | bluetongue antibody of 19 different serological types was found in a group of sentinel cattle near nairobi. a continuous challenge by these 19 strains occurred each year in this location. the sero-conversion rates were shown to vary from year to year and rainfall had no obvious effect upon the conversion rates. the 19 different strains of virus were also shown to be active at five widely scattered sites in different parts of the country. | 1978 | 204705 |
| bluetongue in cattle: a review. | | 1978 | 207405 |
| production of interferon in human cell cultures by a new, potent viral inducer. | a new discovered double-stranded rna inducer of interferon, bluetongue virus (btv), stimulates the production of large amounts of interferon in animals as well as in many types of mammalian cell cultures, including human leukocytes, and continuous cell lines. the exceptional ph lability of btv and its lack of pathogenicity for man further recommend its use as an interferon inducer. among several human cell lines tested, the most efficient producer of interferon was a continuous cell line designa ... | 1978 | 215013 |
| sheep erythrocyte and bluetongue virus antibody responses of spleen cell cultures from mice. | the optimum conditions for the culture of cells from dissociated spleens were determined. routinely, 10(7) cells were seeded per ml of rpmi 1640 medium supplemented with 20% pre-tested foetal calf serum. for the assay of the immune response, cultures were supplemented with 30 mumolar mercaptoethanol. the immune responses to sheep erythrocyte and bluetongue virus antigens were determined by the haemolytic plaque-forming cell assays described by oellermann (1974) and oellermann, carter & marx (197 ... | 1977 | 208037 |
| the use of cattle to protect sheep from bluetongue infection. | studies on the host preferences of culicoides imicola, the vector of bluetongue virus in south africa, are reviewed. there is agreement that this species prefers to feed on cattle but will also feed on other bovidae and sheep. over a seven year period cattle kept near sheep on a natal farm appear to have appreciably reduced the incidence of bluetongue in the sheep. in addition to immunization this "decoy" approach is therefore recommended to assist in the protection of stock from insect borne di ... | 1978 | 215768 |
| bluetongue and epizootic hemorrhagic disease viruses: their relationship to wildlife species. | | 1978 | 216247 |
| bluetongue virus infection in australia. | | 1978 | 217325 |
| bluetongue virus infection in australia. | | 1978 | 217326 |
| experimental infection of culicoides with a bluetongue virus isolated in australia. | | 1978 | 217328 |
| possible windborne spread of bluetongue to portugal, june-july 1956. | the possible sources for the epidemic of bluetongue in portugal at the beginning of july 1956 were examined. introduction through authorized importation of domestic or wild ruminants was not feasible, since no cattle, sheep or goats were imported and the wild ruminants were confined to lisbon zoo, which was too far from the initial outbreaks. weather maps were examined to see if the wind could have carried infected culicoides midges from north africa. on 21 june 1956 infected midges in morocco c ... | 1978 | 212475 |
| pathology of ovine foetus infection with bluetongue virus. | | 1978 | 215253 |
| the isolation of a bluetongue virus from culicoides collected in the northern territory of australia. | | 1978 | 210754 |
| protein synthesis in bluetongue virus-infected cells. | | 1979 | 218351 |
| multiplication rate of bluetongue virus in the vector culicoides variipennis (diptera: ceratopogonidae) infected orally. | | 1979 | 220423 |
| bluetongue virus characterization. | | 1975 | 220625 |
| bluetongue antibody in botswana's domestic and game animals. | bluetongue precipitating antibody was demonstrated in sera of cattle, camels, sheep, goats and seven game species. of the domestic species the percentage of sera positive were; cattle 92%, camels 81%, goats 83% and sheep 36%. sheep sera, unlike those of other domestic species, varied greatly from area to area in the percentage positive. seroconversions were recorded in adult sheep between september and april. in adult cattle there was a gradual decline in the percentage positive with increasing ... | 1979 | 220761 |
| the 1977 outbreak of bluetongue in cyprus. | bluetongue outbreaks, ranging from isolated cases to widespread infections, have occurred in cyprus in about half of the years since 1924. serious outbreaks occurred in 1924, 1939, 1943, 1946, 1951, and 1965. most cases occurred in september, october, november and december. the last outbreak prior to 1977 was in 1969. virus types isolated in the past were types 3 and 4. in 1977 the outbreak was serious, affecting 13.1 per cent of 27,837 in-contact sheep; these were scattered in 303 flocks of 65 ... | 1978 | 218327 |
| characterization of the tubules associated with the replication of three different orbiviruses. | | 1979 | 218352 |
| the susceptibility of cell lines of aedes aegypti (linn.), aedes albopictus (skuse) and aedes pseudoscutellaris (therobald) to infection with blutongue virus. | bluetongue virus multiplied in cell lines derived from aedes albopictus and aedes pseudoscutellaris cells. virus reached a maximum titre in the ae. pseudoscutellaris cells three days post inoculation, and in ae. albopictus cells six days p.i. virus growth was demonstrated in both cell lines at 27 degrees c and 37 degrees c. significant titres of virus were still present in the ae. albopictus cells after five subcultures at 27 degrees c over a period of six weeks. no cytopathic effect was observe ... | 1979 | 218529 |
| bluetongue virus in australia--current situation. | | 1978 | 221937 |
| serological studies on sympatric barbary sheep and mule deer from palo duro canyon, texas. | sera were collected from 12 barbary sheet (ammotragus lervia) and 11 mule deer (odocoileus hemionus) occupying sympatric ranges in palo duro canyon, texas. these were tested for leptospirosis, brucellosis, bovine virus diarrhea, anaplasmosis, vesicular stomatitis, bluetongue (bt), epizootic hemorrhagic disease (ehd), infectious bovine rhinotracheitis (ibr), and coccidioidomycosis. serologic reactors were found to ibr in 3 barbery sheep, bt in 6 barbary sheep and 6 mule deer and ehd in 3 barbary ... | 1979 | 228088 |
| cytokine production by blue tongue virus-infected fetal sheep cells. | the migration inhibition of guinea pig peritoneal macrophages by a factor(s) from media obtained from blue tongue virus-infected monolayer cultures was studied. medium from blue tongue virus-infected sheep fetal cell cultures inhibited migration of guinea pig macrophages from agarose droplets. medium from control cultures and stock virus did not inhibit macrophage migration. medium containing migration inhibiting factor(s) in vitro induced an inflammatory reaction in the skin of a newborn sheep. ... | 1979 | 225275 |
| incidence of bluetongue virus precipitating antibodies in sera of some domestic animals in the sudan. | to determine the presence and prevalence of bluetongue (bt) infection in a variety of domestic animal species in different geographical regions of the sudan, a serological study using the agar gel precipitation technique was initiated. a total of 2142 serum samples were examined. of the numbers tested approximately 28% of sheep, 11.2% of goats, 8% of cattle and 4.9% of camels were positive for group-specific antibodies to bt virus antigen, indicating previous exposure to bt infection. none of th ... | 1979 | 229163 |
| possible origin of the bluetongue epidemic in cyprus, august 1977. | possible origins of an epidemic of bluetongue in cyprus in august 1977 have been analysed. first outbreaks occurred simultaneously in the south-east of the famagusta district and on the north coast of the kyrenia district respectively. although the epidemic was due to type 4, which had been responsible for the previous outbreak in 1969, no evidence of persistance of virus could be found. imports of domestic animals in the past year were not implicated since the imported cattle were introduced on ... | 1979 | 229164 |
| the transmission of the csiro19 strain of bluetongue virus type 20 to sheep and cattle. | | 1979 | 223541 |
| a rapid plaque neutralization test for bluetongue virus. | a bluetongue virus plaque neutralization test, done in small tissue culture wells (2.0 cm2) using minimal antibody-virus contact time, was found to be of comparable sensitivity to more classical methods involving preincubation. by using the cell culture plates as serum dilution wells and adding cells directly to the virus-antibody mixture, a considerable saving in time is realized. because of the small size of the wells, reagent cost and incubator space requirements are reduced making the test m ... | 1979 | 227553 |
| preliminary observations on transplacental infection of bluetongue virus in sheep-a possible overwintering mechanism. | sheep infected mid-gestation with bluetongue virus type 4 and type 16 produced clinically normal lambs that were viraemic at birth. viraemia persisted for two months in some lambs even though they received colostrum. it is suggested that transplacental infection of bluetongue virus in sheep may be an overwintering mechanism for the virus in some areas of the world. | 1979 | 228365 |
| temporal appearance, geographic distribution, and species of origin of bluetongue virus serotypes in the united states. | beginning in 1973, all available laboratory and field strains of bluetongue virus (btv) from the united states were serotyped. of the viral strains serotyped, 27 were collected from 1953 through 1972; 173 were collected from 1973 through 1977. although 20 btv serotypes have been found worldwide, only btv serotypes 10, 11, 13, and 17 have been found in the united states. since 1973, serotypes 11 and 17 have been the prevalent serotypes. samples were collected over a 24-year period in the united s ... | 1979 | 230763 |
| arboviruses isolated from culicoides midges in kenya. | | 1979 | 232109 |
| [orbiviruses]. | | 1979 | 229658 |
| genetic and physiological characterization of temperature-sensitive mutants of bluetongue virus. | complementation studies were carried out, using temperature-sensitive (t-s) mutants of blue-tongue virus (btv). the results proved to be inconclusive as only low indices of complementation were obtained. no discrepancy was found between the previous classification of these mutants in 6 recombination classes and the complementation data recored. in general, the t-s mutants require a latent growth period of 16-20 h at 28 degrees c and maximum titres can be demonstrated 40-48 h post-infection. one ... | 1979 | 233146 |
| the nucleic acid and proteins of epizootic haemorrhagic disease virus. | purified epizootic haemorrhagic disease virus (ehdv) was shown to contain 10 double-stranded rna segments and a double-layered protein capsid with 4 major and 4 minor polypeptides. the virus differed from bluetongue virus (btv), the orbivirus prototype, in that ehdv had an additional minor polypeptide component. this component, together with the major polypeptides p2 and p5, formed the outer capsid layer of the virus. the extra polypeptide apparently stabilizes this layer since, unlike btv, ehdv ... | 1979 | 233147 |
| further characterization of the t-s mutant f207 of bluetongue virus. | temperature-shift experiments verified that the t-s lesion of btv mutant f207 is expressed late in the replication-cycle, that is, at a stage when all virus components have already been synthesized. all viral polypeptides were indeed found in the soluble but not in the particulate fraction of cytoplasmic extracts from infected cultures grown at the non-permissive temperature. this suggests that the t-s lesion could be a defect in one or both of the polypeptides p2 and p5, which are respectively ... | 1979 | 233149 |
| the current status of research on an experimental inactivated bluetongue virus vaccine. | | 1979 | 233389 |
| comparisons of some bluetongue virus isolates by plaque neutralization and relatedness tests. | seven north american bluetongue virus isolates, cloned by plaquing, and sera to five of them were reacted in a plaque neutralization test. using a paired controls system, each virus-serum reaction was studied in terms of the regression of percent neutralization on log serum dilution. antigen-antibody interaction terms in the analysis of effective dose estimates were used to assess the relatedness of the virus isolates. the degree of cross reactivity formed a spectrum from virtually no evidence o ... | 1979 | 229803 |
| production of interferon by human tumor cell lines. | fourteen continuous human cell lines, including nine derived from tumors and five from non-neoplastic tissues, produced interferon in response to induction with bluetongue virus (btv), newcastle disease virus (ndv), and poly(i) . poly(c) complexed with deae-dextran. the seven best interferon-producing cell lines (one from a melanoma, five derived from carcinomas, and one sv40-virus-transformed kidney cell line) responded to at least one of the viral inducers with yields of interferon over 1000 u ... | 1979 | 229805 |
| detection of bluetongue virus serogroup by polymerase chain reaction. | to facilitate detection of active bluetongue virus (btv) infection, a polymerase chain reaction (pcr) protocol was developed. the btv reverse transcriptase pcr (rt-pcr) is a 1-tube reaction and involves chemical denaturation of the double-stranded viral rna target, a complementary dna (cdna) synthesis step, and pcr amplification of the cdna. btv rt-pcr using primers derived from highly conserved genome segment 10 results in a 251-base pair (bp) product. btv rna from all usa prototype serotypes 2 ... | 1992 | 1281002 |
| rna and protein of ibaraki virus. | | 1978 | 232730 |
| strategies for the identification of icosahedral virus receptors. | | 1992 | 1309536 |
| hybridization relatedness of israeli and u.s. bluetongue (blu) serotypes using cdna probes from blu virus strain 11-uc8. | partial cdna clones representing 47%, 96%, and 98% of genome segments 7, 9, and 10, respectively, of a us bluetongue virus (blu) 11 virulent strain were used to study, for the first time, the genetic relationships between israeli blu proto-serotypes and field isolates, and us blu proto-serotypes. their usefulness as group-specific identification probes was also determined. the viral nucleic acid was extracted from the infected cells and the purified dsrna genome segments were fractionated by pol ... | 1992 | 1309643 |
| protective efficacy of virus-like particles for bluetongue disease. | bluetongue virus-like particles (vlps) derived from multiple baculovirus expression vectors have been administered in the presence of various adjuvants to sheep, a vertebrate host susceptible to the virus, and the neutralizing antibody responses are measured. vaccinated sheep are challenged after 4 months of inoculation, and clinical reaction indices and viraemia determined. the results indicate that these multiprotein virus-like particles lacking the genetic material are highly immunogenic and ... | 1992 | 1311487 |
| comparison of the nonstructural protein, ns3, of tick-borne and insect-borne orbiviruses. | the complete nucleotide sequence of the smallest rna segment (segment 10) of broadhaven (brd) virus, a tick-borne orbivirus, was determined from a full-length cdna clone. the genome segment is 702 nucleotides in length and has a coding capacity for two proteins of either 205 or 199 amino acids, having net charges of +16.5 and +17.5, respectively, at neutral ph. comparison of the sequence of rna segment 10 of brd, bluetongue, african horse sickness, and palyam viruses revealed amino acid homology ... | 1992 | 1312282 |
| 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 ... | 1992 | 1312421 |
| three-dimensional structure of single-shelled bluetongue virus. | the three-dimensional structure of single-shelled bluetongue virus has been determined to a resolution of 3 nm by using electron cryomicroscopy and image-processing techniques. the single-shelled virion has a diameter of 69 nm. the three-dimensional structure of the virion has icosahedral symmetry with a triangulation number of 13 in a left-handed configuration. the three-dimensional structure can be described in terms of two concentric layers of density surrounding a central core density. two d ... | 1992 | 1312624 |
| detection of bluetongue virus using a cdna probe derived from genome segment 4 of bluetongue virus serotype 2. | the double-stranded (ds) rna genome segment 4 of bluetongue virus (btv) serotype 2 was cloned and used as a serogroup-specific complementary (c) dna probe for btv diagnosis. a cdna representing a 60% copy of genome segment 4 btv-2 prototype was produced. the specificity of the cdna probe was determined by hybridizing this probe to a northern blot of dsrna (separated by polyacrylamide gel electrophoresis) of plaque-purified btv-2 prototype. this cdna probe was then used to hybridize to the rna sa ... | 1992 | 1313308 |
| 3-d reconstruction of bluetongue virus tubules using cryoelectron microscopy. | bluetongue virus (btv) forms tubules in infected mammalian cells. these tubules are virally encoded entities which can be formed with only one protein, ns1. the ns1 protein does not form a part of virus particles, and its function in viral infection is uncertain. expression of the ns1 gene in insect cells by recombinant baculovirus yields high amounts of ns1 tubules (ca. 50% of cellular proteins) which are morphologically and immunologically similar to authentic btv ns1 and can be isolated to ab ... | 1992 | 1314066 |
| development and evaluation of an enzyme-linked immunosorbent assay for detection of bovine antibodies to epizootic hemorrhagic disease of deer viruses. | an indirect enzyme-linked immunosorbent assay (i.elisa) is described for detection of bovine serum antibody to epizootic hemorrhagic diseases of deer virus (ehdv). serum samples, at a dilution of 1:200, were incubated with group-specific ehdv antigens, pre-adsorbed to microtiter plates. bound antibodies were detected by a murine monoclonal antibody to bovine immunoglobulin (ig)g1 (heavy-chain specific) conjugated with horseradish peroxidase. the performance of the i.elisa in detecting antibodies ... | 1992 | 1317245 |
| antibodies to bluetongue and epizootic hemorrhagic disease viruses from white-tailed deer blood samples dried on paper strips. | the feasibility of using dried blood samples for serologic testing of white-tailed deer (odocoileus virginianus) for antibodies to bluetongue virus (btv) and epizootic hemorrhagic disease virus (ehdv) was tested with matched samples of serum and eluted dried whole blood. results from matched serum virus neutralization (sn) tests indicated that a 1-ml elution from a 1- x 2-cm section of filter paper strip containing dried blood approximated a 1:10 serum dilution. neutralizing antibody titers dete ... | 1992 | 1318425 |
| three-dimensional reconstruction of baculovirus expressed bluetongue virus core-like particles by cryo-electron microscopy. | when the viral proteins vp3 and vp7 of bluetongue virus (btv) are expressed simultaneously in the baculovirus system, core-like particles form spontaneously. the 3-d structure of these core-like particles, determined from cryo-electron micrographs, reveals an icosahedral structure 72.5 nm in diameter with 200 triangular spikes arranged on a t = 13,i lattice; the five spikes around each of the fivefold axes are absent. this is in contrast to the native btv core particles which have a complete t = ... | 1992 | 1318601 |
| sequence conservation among the cognate nonstructural ns3/3a protein genes of six bluetongue viruses. | full-length cdna copies of segment 10 genes of bluetongue virus serotypes 2, 11, 13 and 17 were synthesized by the clamp-r method and inserted into the plasmid puc19. the complete nucleotide sequences of these four cognate genes were sequenced and determined to be 822 nucleotides in length, smallest of the 10 genes in the bluetongue virion. these four cognate gene segments contained two in-phase and overlapping open reading frames capable of coding for two non-structural proteins of 229 and 216 ... | 1992 | 1318624 |