| isoelectric focusing of hog cholera virus. | the isoelectric point of hog cholera virus (alfort strain) has been determined (phi = 4.8). a clear stimulation of its infectivity can be recorded at this ph. the isoelectrophoretic profiles of strains isolated in the field show no significant differences. | 1977 | 18081 |
| quantitative and rapid assays of togaviruses by immunofluorescence. | for the quantitative assay of selected togaviruses, suspensions of bhk cells were inoculated with virus and grown in spinner cultures. at intervals, dependent on the growth characteristics of the viruses, about 10(3) cells were centrifuged on to microscope slides and then stained with fluorescent antibody. for rapid demonstration (2--3 hr) of specific viral antigens, virus was bound in successive dilutions onto microscope slides and stained. binding of specific anti-virus antibodies in both meth ... | 1979 | 40420 |
| [effect of passive immunity on subsequent vaccination against swine fever]. | studied was the effect of a serum paratyph and aujeszky gammaglobulin injected 10, 15, and 20 days prior to the crystal-violet and the lapinized vaccine. if the animals were infected with a pathogenic swine fever virus 10 to 15 days after their treatment with serum at the rate of 0.5 cu. cm per kg, part of them died, and the remaining contracted the disease showing a protracted course. the control vaccination on the 20th day after the animals were injected with serum led to the death of all of t ... | 1975 | 53938 |
| reverse plaque formation by hog cholera virus of the gpe-strain inducing heterologous interference. | a simple and rapid plaque procedure was developed for the assay of hog cholera virus (hcv) of a particular strain, gpe-, based on its intrinsic interference with vesicular stomatitis virus (vsv) on the primary swine testicle cells and on an established swine kidney cell line; the procedure is called the reverse plaque formation (rpf) method. the plaques were produced as colonies of hcv-infected cells which were vsv-sensitive, disintegrated cell sheet. these plaques became visible after 15 to 20 ... | 1976 | 61176 |
| negative staining of a non-haemadsorbing strain of african swine fever virus. | since the application of negative staining, preceded by fixation, prevents the disruption and distortion of the capsid of the african swine fever virus, improved contrast and evaluation of the appearance and size of virus particles in the electron microscope is possible and, in addition, the icosahedral shape of the virus is demonstrable. the mature virus particle contains at least 2 capsid layers and an outer envelope. | 1977 | 78480 |
| a direct plaque assay for hog cholera virus. | direct plaque formation with representative strains of hog cholera virus (hcv) has been obtained using several pig kidney cell lines under agar overlay. hcv-infected cells appear as hazy plaques when viewed against an indirect light source, and as white plaques after neutral red staining. hcv assay by direct plaque procedure is rapid and convenient and gives infectivity titres identical to the fluorescent focus assay technique. | 1978 | 80444 |
| [control of immunity against swine plague by the viral neutralization test on rabbits]. | an idea may be got on the properties of the vaccine by applying a specific gamma-globulin against swine fever in pigs, mixed in definite amounts with lapinized k-vaccine and this mixture is injected to rabbits. by studying the mixture of sera from pigs, vaccinated against swine fever prior to a fixed period of time, and the k-vaccine, applied to rabbits, an idea may be obtained on the tension of the immunity and re-vaccination requirements may be assessed. | 1978 | 87059 |
| properties of border disease virus as studied in a sheep cell line. | a fetal lamb muscle cell line has been isolated in which two strains of border disease virus replicate well and induce a clear-cut cytopathic effect, thus providing a sensitive and practical assay system for both the virus and neutralizing antibodies. this system enabled us to study some characteristics of border disease virus in comparison with two other agents responsible for hog cholera and bovine viral diarrhea. our results indicate that the last virus and the border disease agent are indist ... | 1979 | 94539 |
| electron microscopic observation of african swine fever virus development in vero cells. | african swine fever virus emerges from infected vero cells either from areas of smooth cell surface or from microvilli. the two patterns may occur at different sites on the same cell and are unique for this virus. the scanning electron micrographs supplement regular thin section views. | 1978 | 99488 |
| synthesis of dna in cells infected with african swine fever virus. | incorporation of 14c-thymidine by cells infected with african swine fever virus (asfv) occurs in the nucleus. part of this dna is transferred to the cytoplasm and becomes resistant to dnase. the nuclear fraction washed with triton x100 retained all labeled dna and was able to synthesize viral and cellular dna under in vitro conditions in the presence of the four deoxynucleoside triphosphates, mg+2, and sucrose. under similar conditions nuclei from uninfected cells synthesized very little dna. | 1979 | 117788 |
| the structural components of hog cholera virus. | hog cholera virus grown in pk-15 cells and sk-cells was labeled with [35s]methionine and [3h]uridine. at least 3 polypeptides were resolved by polyacrylamide gel electrophoresis after disruption of the virus with sodium dodecyl-sulfate. the molecular weights of the structural proteins were determined to be 55000 (p55), 46000 (gp46), and 36000 (p36). the molecular weight of the viral rna was determined to be about 4 x 10(6) in polyacrylamide-agarose-gel electrophoresis. in sucrose gradients the r ... | 1977 | 141817 |
| swine buffy coat culture: an aid to the laboratory diagnosis of hog cholera. | a 2-step technique for the isolation of hog cholera (hc) virus consisting of an initial culture on buffy coat (bc) cultures and subinoculation to a pig kidney cell line (pk-15) was described. by this technique, hc virus was confirmed in specimens from 65 herds in which the conventional cell culture isolation technique failed. the herds were located in 20 states and puerto rico. specimens from 29 of the 65 herds were inoculated into specific-pathogen-free (spf) pigs. hog cholera virus was recover ... | 1975 | 163064 |
| tween 80: a marker for differentiation of hog cholera and bovine viral diarrhea viruses. | markers for differentiating hog cholera and bovine viral diarrhea viruses were studied using tween 80, chloroform, trichlorotrifluoroethane and tri (n-butyl) phosphate. attenuated a and virulent ames strains of hog cholera virus were employed. moreover, the nadl pk-15 cell culture adopted strain and low cell culture passaged purdue strain of bovine viral diarrhea virus were used. these viruses were reacted with 2,500 micrograms/ml of tween 80 for one hour at 37 degrees c. when attenuated a and v ... | 1977 | 188531 |
| [the immunity against challenge with swine fever virus of piglets from sows vaccinated with c-strain virus (author's transl)]. | the protective value of maternal antibodies against exposure by contact to virulent swine fever virus was investigated in a group of 40 piglets at the age of 33-40 days. the piglets were from a single farm and derived from 10 sows which had been vaccinated once with c-strain virus 5.5 months before farrowing. four contact controls of approximately the same age as the test-groups and born from non-vaccinated sows died 4-10 days (av. 7.5 days) after the onset of symptoms. three pigs from the group ... | 1977 | 199961 |
| differences in pathogenicity and antigenicity among hog cholera virus strains. | using antiserum against a particular strain of bovine viral diarrhea virus, the strains of hog cholera virus were divided into two groups, h and b, on the basis of the difference in the degree of neutralization. group h consisted of strains reacting poorly in neutralization, and group b consisted of strains reacting well with bovine viral diarrhea antiserum. most of the strains of group h induced a typical clinical form of hog cholera in experimentally infected pigs. inoculation of pigs with a s ... | 1977 | 203871 |
| [reverse plaque formation by hog cholera virus inducing interference with vsv (author's transl)]. | infection of pk15 cells with various strains of hog cholera (hcv, togaviridae) induces a transient refractory state to vsv. the reverse plaque procedure is convenient for hcv titration of virulent, "chronic" and attenuated strains. | 1978 | 205199 |
| nonarbo-togaviridae: comparative hydrodynamic properties of the pestivirus genus. brief report. | the sedimentation coefficient and buoyant density of hog cholera, bovine viral diarrhea and border disease viruses, have been compared with those of representative members of the family togaviridae. it appears that the pestivirus genus is a homogeneous group which is not only antigenically but also structurally, unrelated to the other genera of the togavirus family. | 1979 | 232414 |
| transmission of hog hog cholera virus by mosquitoes. | mosquitoes trapped during an epizootic of hog cholera (hc) in maryland in 1969 were prepared into 40 pools which were inoculated in pigs. hog cholera virus was confirmed in pigs inoculated with 8 of 40 pools of mosquitoes. generally, the pigs contracting hc developed chronic infections with persistent viremia that lasted 30 or more days. two pigs seemed healthy when euthatized 62 and 80 days after inoculation, yet viremia of high titer was detected in each. experimental studies were performed wi ... | 1975 | 237444 |
| the growth of virulent african swine fever virus in pig monocytes and macrophages. | the replication of virulent african swine fever virus (asfv) in cultures of monocytes and macrophages derived from pig bone marrow (pbm) and pig leukocyte (pl) cells was investigated by light microscopy, immunofluorescence, haemadsorption and infective virus release. monocytes showed a high rate of infection and complete destruction within 2 to 3 days, whereas macrophages had only a very low level of infection and survived to form persistently infected cultures. these observations may explain th ... | 1978 | 340610 |
| african swine fever: microplaque assay by an immunoperoxidase method. | a microplaque assay for vero cell-adapted lisborn '60 strain of african swine fever virus (l'60-uncloned) and a large plaque-forming strain cloned from the l'60-uncloned strain was developed by an immunoperoxidase method. the immunoperoxidase method can be used to stain microplaques of 3 days after inoculation, whereas the conventional plaque assay requires 5 to 7 days to develop visible plaques. a linear relationship between viral concentration in the inoculum and plaque numbers was observed. v ... | 1978 | 345892 |
| [isolation of a cytolytic strain of hog cholera virus from ib-rs2 cells (author's transl)]. | an infectious agent, able to induce a definite cytopathic effect in pig kidney cell monolayers, was isolated from the ib-rs2 cell line. immunofluorescence, seroneutralization and ultracentrifugation studies have permitted to identify this agent as hog cholera virus (hcv). representative hcv-strains being devoid of pathogenicity in tissue culture, the practical and theoretical interest of such an isolation is discussed. | 1978 | 358888 |
| effect of disodium phosphonoacetate and iododeoxyuridine on the multiplication of african swine fever virus in vitro. | disodium phosphonoacetate (paa) was found to inhibit the replication of african swine fever virus (asfv). the action of this compound has been compared with the inhibitory capacity of iododeoxyuridine (idu) upon asfv growing in vero cells. the study was done by the immunofluorescence technique in order to detect formations of cytoplasmic virus antigens and inclusion bodies; both were found to be inhibited by idu and paa. at 100 microgram/ml, idu blocked completely the multiplication of asfv and ... | 1979 | 378573 |
| a solid-phase enzyme linked immunosorbent assay for the detection of african swine fever virus antigen and antibody. | a solid-phase enzyme-linked immunosorbent assay was developed to measure both african swine fever virus (asfv) antigen and antibody. experiments showed it to be reproducible and able to detect limiting antigen concentrations of 50--500 had50/ml. the assay was more sensitive than those used at present to detect asfv antibody and it is suggested that it might be of great diagnostic use in countries where african swine fever has recently appeared. | 1979 | 385771 |
| requirement of cell nucleus for african swine fever virus replication in vero cells. | the role of the cell nucleus in the development of african swine fever virus in vero cells has been studied. no viral growth could be detected in enucleated cells under conditions that allow normal development of sindbis virus. furthermore, african swine fever virus dna synthesis was inhibited more than 95% after infection of enucleated vero cells as compared with normal cells. | 1977 | 403300 |
| [diaplacental transfer of nonvirulent tvm-1 hog-cholera virus]. | | 1977 | 406714 |
| [comparative precipitation studies between the highly-virulent virus of european swine fever, swine-fever-virus split products and precipitating swine-fever antigens from the organs of swine-fever infected pigs]. | | 1977 | 414484 |
| thermal inactivation of hog cholera virus in ham. | experiments were conducted to determine the temperatures required to inactivate hog cholera virus (hcv) in fresh ham after 1 minute and in cured and processed (canned) ham after 90 minutes. a momentary or "flash" temperature of 71 c for 1 minute caused inactivation of the virus in 15 of 15 cubes (2 cm3) of ham. hog cholera virus was destroyed in 21 of 21 canned hams (weighing 0.91 kg each) when an internal temperature of 65 c was sustained for 90 minutes. pigs were found to be more sensitive tha ... | 1979 | 475124 |
| solid-phase radioimmunoassay techniques for the detection of african swine fever antigen and antibody. | a solid phase radioimmunoassay (ria) has been successfully developed to measure both african swine fever virus (asfv) antigen and antibody. studies show that the assay is reproducible and will detect limiting antigen concentrations equivalent to 50--500 had50/ml. both direct and indirect antibody ria have been developed and have proved to be approximately 100 times fore sensitive than the complement fixation test at present available and 1000 times more sensitive than the immuno-electro-osmophor ... | 1979 | 489964 |
| the replication of virulent and attenuated strains of african swine fever virus in porcine macrophages. | the replication of virulent and attenuated strains of african swine fever virus (asfv) was studied in pure cultures of swine macrophages. to ensure complete destruction of the macrophage monolayers about 50--100 times more virulent asfv was needed than attenuated virus although both isolates could be used to establish persistently infected cultures. interferon did not appear to influence virus yields from such cultures. fluorescent and electron microscopy studies of infected macrophages suggeste ... | 1979 | 496644 |
| [studies on the increase of weights of lymphatic glands, of lymph and peritoneal fluid and their contents of chymotrypsin and virus in pigs suffering hog cholera (author's transl)]. | swine fever is conceived as a disorder of the enzyme systems, that are controled by serine proteases. the virus is replicated in the cells of the lymphomycoid complex, whereby the production of a chymotrypsin is induced. in swine fever the lymphatic glands and the lymph flow are increased. fifteen normal pigs had chymotrypsin contents in the lymph of the body lymphnodes of 0,4 u/l, nine pigs suffering hog cholera 1,5 u/l. in the intestinal lymphnodes the chymotrypsin concentration was normally 2 ... | 1979 | 506545 |
| cross-links in african swine fever virus dna. | african swine fever virus dna sediments in neutral sucrose density gradients as a single component with a sedimentation coefficient of 60s. in alkaline sucrose density gradients, this material shows two components with sedimentation coefficients of 85s and 95s, respectively. the sedimentation rate value of alkali-denatured virus dna in neutral sucrose density gradients and the renaturation velocity of denatured dna show that is reassociated much faster than expected from its genetic complexity. ... | 1979 | 513189 |
| [nature and specificity of the auxilliary rabbit test in the diagnosis of swine fever]. | experiments were carried out with the aim to reveal the causes for the inhibited temperature reaction in rabbits to swine pest virus strain k in case of previous injection with virulent pest virus. it was established that in the serum of rabbits injected with virulent swine pest virus specific antibodies are found, which are capable to neutralize the lappinized k virus introduced later. this phenomenon which is specific enough and highly sensitive can be used with success as an auxiliary biologi ... | 1979 | 532090 |
| an immunofluorescence neutralization test in disposable plastic trays for demonstrating classical swine fever virus antibodies. comparison of a micro with a macro method. | | 1979 | 539221 |
| [viral carrier state and viral excretion in classical swine fever]. | studies on swine pest virus carrying and elimination on swine vaccinated by lapinizated vaccine strain "k" from rabbits were performed. vaccinated swine were injected with the pathogenic virus on the 60th day post vaccination and to them were added not immunized swine with the aim to discover virus elimination. the experimental swine were decapitated on the 3, 5, 6 and 7th day post infection. alternating passages were made by emulsion of the inner organs of these swine on not immunized swine as ... | 1979 | 549263 |
| african swine fever: pathogenicity and immunogenicity of two non-haemadsorbing viruses. | the virulence of 2 non-haemadsorbing african swine fever virus isolates were compared with 2 haemodsorbing viruses. while 3 of these isolates usually produced acute death in pigs, 1 non-haemadsorbing virus caused either a fatal infection with an extended course, or few or no obvious signs of infection. pigs that survived infection with the latter virus were resistant to the lethal effects of the other 3 strains as well as to a pool of 7 isolates made from ornithodorus porcinus porcinus (senus wa ... | 1979 | 551362 |
| hog cholera virus : sensitivity to hydrolytic enzymes. | the actions of trypsin and phospholipase c on th infectivity of hog cholera virus (hcv) were studied. inactivation kinetics reveal a marked decrease of the infectivity of hc virus in the presence of these two agents. the particular sensitivity of this virus towards proteolytic action sheds light on certain of its behavior characteristics in the field. virus infectivity seems to be dependent on the integrity of membrane phospholipids. no relation was observed between the rate of inactivation and ... | 1977 | 560170 |
| improved method for the purification of hog cholera virus grown in tissue culture. | a method for purification of hog cholera virus (hcv) is presented. cell-associated virus was extracted from pk15 cells 17 hours p.i. by fluorocarbon treatment. the virus was concentrated by polyethylene glycol precipitation and partially purified by pelleting on a fluorocarbon cushion. final purification was achieved by rate zonal centrifugation in a 7--35 per cent sucrose gradient. this procedure permits a recovery of approximately 40 per cent of viral infectivity. a specific infectivity of abo ... | 1977 | 560840 |
| african swine fever virus replication in porcine lymphocytes. | purified preparation of porcine lymphocytes were infected with three isolates of virulent african swine fever virus (asfv). electron microscopy showed the presence of small numbers of mature virus particles in degenerating cells. the titres of infective virus released were low and reached a maximum by 24 h after infection. | 1977 | 562925 |
| the association of african swine fever virus with blood components of infected pigs. | the distribution of african swine fever virus (asfv) in whole blood, plasma, red blood cells (rbc) and white blood cell (wbc) sub-populations was determined in pigs infected with virulent virus. changes in the rbc and wbc populations were also examined. total wbc counts decreased and rbc numbers remained unchanged during the course of the disease. the number of circulating lymphocytes decreased whilst neutrophil numbers increased owing to the replacement of mature forms by juveniles. virus was p ... | 1977 | 563710 |
| residual viruses in pork products. | partly cooked canned hams and dried pepperoni and salami sausages were prepared from the carcasses of pigs infected with african swine fever virus and pigs infected with hog cholera virus. virus was not recovered from the partly cooked canned hams; however, virus was recovered in the hams before heating in both instances. both african swine fever virus and hog cholera virus were recovered from the dried salami and pepperoni sausages, but not after the required curing period. | 1978 | 564162 |
| the replication of african swine fever virus in pig endothelial cells. | | 1978 | 566606 |
| structural similarities of hog cholera virus with togaviruses. | hog cholera virus grown in pk-15 cells was purified by centrifugation through a sucrose cushion followed by sucrose gradient centrifugation. analysis of virus labeled externally with [3h]sodium borohydride on polyacrylamide gel electrophoresis revealed two glycoproteins, gp55 and gp46. a third structural polypeptide, p36, seems not to be glycosylated. the gp46 was also found in the virus-free supernatant of infected cells. it could be demonstrated by radioimmune precipitation of virus labeled wi ... | 1978 | 567468 |
| [clinical and pathomorphological studies of rabbits injected with virulent and lapinized swine plague virus]. | investigations were carried out to establish the clinical and morphological reactions in rabbits following the consecutive infection with the virulent vratsa strain and the lapinized k strain of the swine fever virus. it was found that although the virulent strain did not cause a thermal response there were morphological lesions in the body of the rabbits, characterizing the presence of an immune response. the latter was shown to inhibit the thermal reaction in the animals after infecting with l ... | 1978 | 571168 |
| comparison of the immune response in serum and bucco-pharyngeal secretions following immunization by different routes with a live hog cholera virus vaccine (thiverval strain). | the influence of vaccination route on local and systemic immune response was studied with hog cholera virus vaccine. kinetics of antibody synthesis in serum and bucco-pharyngeal secretion was observed. results show that, whatever the vaccination route (intranasal or intramuscular) a good systemic and local immune response were induced and pigs resisted to a virulent challenge. however the highest local immune response was obtained by intranasal vaccination with large vaccine dosage (10(7) p.f.u. ... | 1977 | 596794 |
| [hog cholera virus: influence of colostral passive antibody on immune response of pig following vaccination with the rabbit adapted chinese strain (author's transl)]. | using the rabbit adapted chinese strain of hog cholera, active immunization of piglets having passive colostral antibodies was studied. 65 piglets born from 11 sows were used. concerning sows, vaccination was performed 5-6 months and 1 month before service (3 sows), 30 days (2 sows) and 60 days (3 sows) after service. divided in 5 lots, piglets were vaccinated at 4 different periods after birth (15, 30, 60 and 90 days). hog cholera immunity was determined for each animal by means of kinetic of s ... | 1977 | 606138 |
| diagnostic and prophylactic problems connected with the control of foot and mouth disease, brucellosis, tuberculosis and swine fever in italy. | | 1977 | 618072 |
| cellular and humoral immune response in pigs given vaccinal and chronic hog cholera viruses. | humoral immune response (seroneutralization) and cellular immune response (lymphocyte-stimulation test) were analyzed in pigs inoculated with low virulent strains of hog cholera virus or vaccinated with a live-virus vaccine. vaccinated animals exhibited an intense neutralizing antibody production, but cellular immune response was not detected. neutralizing antibodies were not found in infected pigs, but a brief cellular immune response (18 days after inoculation) was observed. | 1978 | 736342 |
| influence of colostral antibodies on pig immunization against hog cholera virus. | | 1978 | 747321 |
| [pathomorphological changes in swine plague and their diagnostic value]. | | 1978 | 751319 |
| [attempts to purify strain k of the virus of classical swine plague]. | in the treatment of spleens and lumph nodes of rabbits infected with strain k, with the use of freon 113 the virus was freed from proteins up to 92-96 per cent. the infective power of the purified virus proved equal to that of the initial non-purified virus proved equal to that of the initial non-purified virus, and this points to the full extraction of the virus itself. the antigenic properties of the purified virus were demonstrated through agar gel precipitation with normal and hyperimmune se ... | 1975 | 814700 |
| [effect of heating on the survival of swine fever virus in pasteurised canned ham from experimentally infected animals (author's transl)]. | experimentally infected pigs were slaughtered during viraemia. the hams were prepared according to the industrial process and packed in tins with an average content of 5.6 kg. the tins were then heated in the course of which temperatures in the centre of the hams reached maximum values varying between 62.5 and 68.5 degrees c. within 24 hours of heating the centre of the ham was homogenised and one of two piglets were inoculated with 40 to 80 ml of a 25 per cent suspension. virus was recovered fr ... | 1976 | 827818 |
| [a new inactivated vaccine against classical swine fever]. | authors used a wild strain of classical swine fever virus alfort a19, grown on pk15 cell culture. virus is concentrated by ultrafiltration technique, inactivated with glycidaldehyde and then mixed with an oil adjuvant. results have brought into evidence the absolute innocuousness of this vaccine and animals given 2 doses of 2.5 ml or 1 dose of 5 ml were resistant to a challenge 2 months after vaccination. protection lasts one year, at least. | 1976 | 828543 |
| cellular immunity demonstrated in pigs infected with african swine fever virus. | twenty-two pigs infected with african swine fever virus (asfv) were used to demonstrate delayed hypersensitivity (dh) in vitro by the leukocyte migration-inhibition test. the results indicated that asfv-infected pigs developed dh against asfv antigen (asf antigen) as early as 20 days after inoculation, and the presence of viremia did not interfere with the leukocyte migration-inhibition test. three asfv-infected pigs that were also sensitized to mycobacterium developed dh against both asf antige ... | 1977 | 835865 |
| [pathomorphological studies of the infections manifested in swine after vaccination with lapinized strain k vaccine against hog plague]. | pigs that had died after vaccination with a lapinized k strain of the swine fever virus at the persistence of another infection showed morphologic and histopathologic changes that were largely similar to those observed in cases of classic hog cholera. the difference consisted in the frequence and intensity of the lesions. histopathologically essential proved the investigation of the brain. the latter usually presents a prevailing activation and hyperplasia of the capilary endothelium, while in c ... | 1977 | 898647 |
| local immunity in the pig respiratory tract. ii. -- relationship of serum and local antibodies. | antibody passage from blood to respiratory secretions was studied on pigs. the animals were passively immunized and have a high anti-hog cholera serum antibody titer. with normal animals as with swine influenza animals, no serum antibody could be recovered neither in buccopharyngeal secretions nor in lung washings: it seems that in such conditions no detectable transudation occurs from blood to local secretions. following intranasal inoculation of swine influenza virus or intramuscular injection ... | 1977 | 907266 |
| transmission studies with african swine fever virus. infections of pigs by airborne virus. | | 1977 | 908773 |
| transmission studies with african swine fever virus. the early distribution of virus in pigs infected by airborne virus. | | 1977 | 908774 |
| purification and physicochemical characteristics of african swine fever virus. | methods for the purification of african swine fever virus (asfv) and its dissection into two fractions are described. the difficulties which have been encountered previously in attempts to purify the virus, namely contamination with large amounts of cellular constituents and aggregation of the virus particles, have been overcome by treatment with tween 80 and by the use of 1 m-nacl in the sucrose gradients. five major polypeptides, mol. wt. 10(3) x 125 (vp1), 76 (vp2), 50 (vp3), 44 (vp4) and 39 ... | 1976 | 965949 |
| sensitivity of swine buffy coat culture to infection with hog cholera virus. | the susceptibility of swine buffy coat (bc) cultures inoculated with hog cholera (hc) virus in the presence of homologous antiserum was greater than that of a pig kidney (pk-15) cell line similarly inoculated. the virus was isolated from bc cultures grown in the presence of 0.1% hyperimmune serum, whereas it could not be consistently recovered from the pk-15 cell line in which hyperimmune serum concentrations exceeded 0.025%. maximal viral titers in bc culture were reached between postinoculatio ... | 1976 | 984563 |
| sub-clinical swine fever: a survey of neutralizing antibodies in ther sera of pigs from herds having reproductive failures. | sera harvested from breeding farms where reproductive failures were observed but where swine fever vaccination was not carried out, where tested for the presence of neutralizing antibodies specific for swine fever virus. neutralization tests were performed in tissue culture using two viruses strains: the american serological variant "331" strain isolated by mengeling (1969) and the virulent "normal strain" alfort. for comparison, sera harvested from healthy, vaccinated and unvaccinated breeding ... | 1976 | 984714 |
| isolation and segregation of non-haemadsorbing strains of african swine fever virus. | | 1976 | 1014300 |
| [the propagation of swine fever virus in cultures of macrophages and lymphocytes of normal and immune pigs (author's transl)]. | swine fever virus is replicated in the cells of the lymphoid complex. during the course of the disease cell-destruction, leucopenia and a disturbance of globulin and transferrin production is described. in the case of recovering firstly the leucocyte population, specially the lymphocytes, later on antibody titer increase. the production of virus neutralizing antibodies is not recognizable to be the cause of a recovery, the latter seems to be initiated by the production of a newly formed cell pop ... | 1976 | 1015008 |
| swine fever: influence of passive immunity on pig immune response following vaccination with a live virus vaccine (thiverval strain). | the influence of passive immunity on the immune response to swine fever virus (s.f.v.) was investigated in pigs injected with variable amounts of s.f.v. antibodies instead of piglets from immune sows. the passive immunity suppresses the primary serum antibody response normally observed after vaccination with the thiverval strain of s.f.v. this inhibition is either partial or complete depending on the amount of injected antibodies. whatsoever the passive immunity intensity, a priming occurred (ev ... | 1976 | 1028380 |
| [studies of the carrier state and excretion of the pathogenic plague virus in vaccinated swine]. | investigations were carried out on the presence of carriers and the excretion of the virulent swine fever virus in pigs vaccinated with the lapinized vaccine strain k. on the 15th, 25th, and 35th day following injection with the virulent virus a pig was killed each time and material was taken for morphologic studies and immunofluorescence microscopy. the results of the investigations were negative except for two pigs the cerebrum of which showed perivascular, slightly to moderately expressed lym ... | 1976 | 1030872 |
| plaque formation by african swine fever virus in chick embryo fibroblasts in the absence of co2 atmosphere. | a plaque assay method using asfv previously adapted to growth in chick embryo fibroblasts is described. chick embryo fibroblast monolayers under bactoagar or methylcellulose have been employed using cysteine, arginine, deae-dextran and hepes as additives. plaque production was optimal under methylcellulose. hepes rendered the plaques more clear when used with the overlay. arginine enhances plaque formation with bactoagar, and deae-dextran doubles the plaque size. the growth curve of asfv in chic ... | 1976 | 1033755 |
| [comparison of 2 in vitro methods of titration of antibodies neutralizing the classic swine plague virus]. | swine fever virus neutralization have been studied by the following method: variable plaque forming units numbers are mixed with a predetermined serum dilution. infectivity is measured before (vo) and after (vr) neutralization reaction. neutralization index (n.i. = logvo/v) represent the difference between the two titers. it had been demonstrated that mass law is a good approximation to describe swine fever virus neutralization. so the most useful form in which to express the relation between n. ... | 1976 | 1036215 |
| [serological identification and behavior of the highly virulent swine fever virus in immunoelectrophoresis]. | | 1975 | 1136613 |
| the use of a microtitration technique for the routine assay of african swine fever virus. brief report. | | 1975 | 1168046 |
| the basis of arbovirus classification. | the biologically defined set of arboviruses contains well over 300 separate viruses which have been subdivided into some 40 serological groups on the basis of antigenic cross-reactivity. more than three quarters of all arboviruses can now bw placed into one of the following five major taxonomic genera based upon the fundamental properties of the virion: alphavirus, flavivirus, orbivirus, rhadovirus, bunyavirus. there are 20 alphaviruses, representing serological group a, and 57 flaviviruses in s ... | 1975 | 1207193 |
| occurrence of contaminating viruses in various swine fever virus strains. ii. studies on gillespie's cytopathic type-a strain and on other strains. | | 1975 | 1233873 |
| stabilization of hog cholera virus by dimethyl sulfoxide. | the stability of hog cholera virus through five freeze-thaw cycles in the presence and absence of dimethyl sulfoxide was studied. in the absence of dimethyl sulfoxide the hog cholera virus titer was reduced 52% to 91% following successive freezing and thawing cycles. however, when dimethyl sulfoxide was added to the viral suspension the virus titer appeared to remain the same after the same number of freezing and thawing cycles. | 1975 | 1236769 |
| ultrastructural study of african swine fever virus replication in cultures of swine bone marrow cells. | cultures from pig bone marrow cells were infected with asfv and the replication cycle was studied. in the cytoplasmic replication areas there are a differentiation of membrane segments. some of them are polygonal, which give rise to virus particles. an over production of viral coded materials, including non-polygonal membranes seems to be an important feature of the replicative cycle of asfv in this cell system. viruses are released enveloped with a cellular membrane. paracrystalline arrays of v ... | 1975 | 1239040 |
| [viability of the strein k hog cholera virus in the organism of swine]. | | 1975 | 1239847 |
| [antibody formation in swine vaccinated with a lapinized k-vaccine and serum against hog cholera]. | immunized were experimentally a total of 10 pigs with 2 cu. cm lapinized k vaccine and 10 cu. cm swine fever serum each. reimmunization was performed a month later using only vaccine. after three and a half months the experimental pigs were included into the group of pigs producing serum against swine fever that were preliminary simultaneously immunized against hog cholera by the classical method. swine fever antibodies in the serum of the experimental pigs showed a concentration that was equal ... | 1975 | 1239855 |
| [immunological reactivity of suckling pigs born to sows immunized against the lapinized k vaccine]. | the lapinized k vaccine was used to immunize 25 five-day-old pigs and 27 ten-day-old pigs. a group of 10 pigs were also included in the experiment as controls. all animals originated from eight sows treated with a lapinized k vaccine on the 70th day of pregnancy. on the 14th day following vaccination part of the pigs of the two test groups were revaccinated. three months later half of the immunized pigs were infected with a pathogenic swine fever virus. the remaining animals were infected then i ... | 1975 | 1241625 |
| [experiments to determine the immunizing dosages in a single vaccinal dose of dried, lapinized k vaccine against swine plague]. | investigated was the amount of the immunizing doses per one vaccinal pig dose of five operative numbers of the lapinized k vaccine against swine fever. for this purpose pigs were immunized with 100, 200, 300, 400, and 500 fold dilutions of the vaccinal dose. a couple of weeks later the pigs were infected with 10(6)ld50 each of a pathogenic swine fever virus. it was found that the immunizing doses for the individual operative numbers of the vaccine vary in number from 100 to 400 in one vaccinal d ... | 1976 | 1258353 |
| muscidae (diptera): experimental vectors of hog cholera virus. | | 1976 | 1263216 |
| a preliminary map of epitopes on envelope glycoprotein e1 of hcv strain brescia. | monoclonal antibodies (mabs) directed against envelope glycoprotein e1 (gp51-54) of hog cholera virus (hcv) strain brescia have been shown to recognize four different antigenic domains a, b, c and d. epitopes of within domain a have mainly been found conserved among hcv strains, whereas epitopes within domains b, c and d are not conserved. we used transiently expressed hybrid e1 genes of hcv strains brescia and "c" to map the non-conserved epitopes on e1. epitopes in domains b and c are located ... | 1992 | 1282755 |
| genes homologous to ubiquitin-conjugating proteins and eukaryotic transcription factor sii in african swine fever virus. | the nucleotide sequence of the 6004-bp ecori i fragment of african swine fever virus dna has been determined. translation of the sequence revealed eight closely spaced open reading frames (orfs), three of them reading rightward and five leftward. northern blot hybridization analysis indicated that orfs i73r and i78r were transcribed early in infection, whereas orfs i177l, i196l, and i329l were expressed at late times. transcripts for orfs i215l, i226r, and i243l were detected at low levels in ea ... | 1992 | 1309282 |
| heterogeneous expression of the non-structural protein p80/p125 in cells infected with different pestiviruses. | in order to analyse the expression of the non-structural (ns) protein p80/p125 in cells infected with different pestiviruses at the protein level, radioimmunoprecipitations with the pestivirus-specific monoclonal antibody (mab) bvd/c16 were performed. cell lysates infected with cytopathic (cp) and non-cytopathic (ncp) bovine viral diarrhoea (bvd) virus strains and isolates, and with hog cholera (hc) virus strains were analysed. from cpbvd virus-infected cells, the mab precipitated one or more pr ... | 1992 | 1309861 |
| a ubiquitin conjugating enzyme encoded by african swine fever virus. | the post-translational modification of proteins by covalent attachment of ubiquitin occurs in all eukaryotes by a multi-step process. a family of e2 or ubiquitin conjugating (ubc) enzymes catalyse one step of this process and these have been implicated in several diverse regulatory functions. we report here the sequence of a gene encoded by african swine fever virus (asfv) which has high homology with ubc enzymes. this asfv encoded enzyme has ubc activity when expressed in escherichia coli since ... | 1992 | 1310934 |
| the pestiviruses. | | 1992 | 1315479 |
| a gene homologous to topoisomerase ii in african swine fever virus. | a putative topoisomerase ii gene of african swine fever virus was mapped using a degenerate oligonucleotide probe derived from a region highly conserved in type ii topoisomerases. the gene is located within ecori fragments p and h of the african swine fever virus genome. sequencing of this region has revealed a long open reading frame, designated p1192r, encoding a protein of 1192 amino acids, with a predicted molecular weight of 135,543. open reading frame p1192r is transcribed late after infec ... | 1992 | 1316688 |
| evolution of thymidine and thymidylate kinases: the possibility of independent capture of tk genes by different groups of viruses. | phylogenetic analysis of viral and cellular thymidine and thymidylate kinases was performed using computer-assisted methods. multiple alignments and tentative phylogenetic trees were generated for the two families of these enzymes, which include a) thymidine kinases (tk) of mammals, poxviruses, african swine fever virus, e. coli, and bacteriophage t4; and b) thymidylate kinases (thyk) of yeast and poxviruses and distantly related herpesvirus proteins with both enzymatic activities. analysis of t ... | 1992 | 1317076 |
| identification of an african swine fever virus gene with similarity to a myeloid differentiation primary response gene and a neurovirulence-associated gene of herpes simplex virus. | here we describe an open reading frame (lmw23-nl) in the african swine fever virus genome that possesses striking similarity to a murine myeloid differentiation primary response gene (myd116) and the neurovirulence-associated gene (icp34.5) of herpes simplex virus. in all three proteins, a centrally located acidic region precedes a highly conserved, hydrophilic 56-amino-acid domain located at the carboxy terminus. lmw23-nl predicts a highly basic protein of 184 amino acids with an estimated mole ... | 1992 | 1323711 |
| protection of piglets born from ruminant pestivirus experimentally infected sows, and their contacts, to the challenge with hog cholera virus. | two groups, a and b, of two specific pathogen-free pregnant sows were experimentally infected between the 25th and 29th days post-breeding with two strains of ruminant pestivirus: nadl cytopathic bovine viral diarrhoea virus for group a and aveyron non-cytopathic border disease virus french strain for group b. two other pregnant sows (group c) were kept uninoculated as control. when 7 weeks old, 8 piglets of group c were put in contact with 4 piglets of group a (group d), and 8 other piglets of ... | 1992 | 1324630 |
| the hog cholera virus. | hog cholera virus (hcv) is a spherical enveloped particle of about 40-60 nm dia. the viral genome is a single strand rna of about 12,000 bases with positive polarity. one single large open reading frame codes for presumably four structural, i.e. three glycoproteins and a core protein, and about three to five nonstructural proteins. the functional role is not yet fully clear for all viral proteins. hcv belongs to the pestivirus group and it is closely related to bovine viral diarrhoea and border ... | 1992 | 1325334 |
| hog cholera diagnostic techniques. | clinical signs and lesions can sometimes provide the basis for a presumptive diagnosis of hog cholera (hc). however, an accurate diagnosis requires laboratory testing. the usual procedure for the detection of viral antigen is the examination of cryostat sections stained with fluorescein-conjugated hc antiserum. a more definitive technique is isolation of the virus in pk-15 cell cultures and identification of the viral antigen in cells using an hc fluorescent antibody conjugate. as bovine viral d ... | 1992 | 1325335 |
| african swine fever virus encodes a gene with extensive homology to type ii dna topoisomerases. | nucleotide sequencing of a virulent african swine fever virus (asfv) isolate (malawi lil20/1) identified an open reading frame of 1191 amino acid residues encoding a protein of 134.9 kda. this gene mapped to the sali i and j restriction endonuclease fragments of the asfv genome. the predicted polypeptide was found to share 21.1% identity over a 1077 amino acid region with the human type ii dna topoisomerase. the sequence is compared to other type ii dna topoisomerases and the possible roles in a ... | 1992 | 1335084 |
| thermal and ph stability of pestiviruses. | three strains/isolates of hog cholera virus (hcv) and two strains/isolates each of cytopathogenic (cp) and non-cytopathogenic (ncp) biotype of bovine virus diarrhoea virus (bvdv) were each exposed to ph 3, 3.5 and 4 at 4 degrees c, 21 degrees c and 37 degrees c in a number of combinations. infectivity titration and half-life determinations following correlation and regression analysis showed a significant temperature-dependent shortening of half-lives within the ph range investigated. at ph 3, m ... | 1992 | 1335310 |
| analysis of t lymphocyte subsets proliferating in response to infective and uv-inactivated african swine fever viruses. | the proliferative response to infective and uv-inactivated african swine fever virus was analyzed in cells from pigs surviving an experimental infection with attenuated virus. all the pigs showed strong dose-dependent proliferative responses to both infective and uv-inactivated virus. this response was also observed when nitrocellulose-bound solubilized virus proteins were used in the assay. heterologous isolates also induced proliferation, however it was significantly lower than that induced by ... | 1992 | 1362304 |
| flow cytometric analysis of african swine fever virus-induced plasma membrane proteins and their humoral immune response in infected pigs. | african swine fever (asf) virus-induced plasma membrane proteins may contribute to the protective immune response against the disease since they can be involved in the antibody-mediated lysis of infected cells. in this study we describe the regulation of asf virus-induced plasma membrane protein expression and its antibody induction in pigs after viral infection by flow cytometric analysis. more than 80% of infected cells contained viral antigens on the surface membranes at 6 hr postinfection (h ... | 1992 | 1376539 |
| characterization and pathogenicity for pigs of a hog cholera virus strain isolated from wild boars. | one hog cholera virus strain isolated from an outbreak of the disease in a wild boar breeding herd in brittany (france) in 1990 has been characterized with a panel of monoclonal antibodies to hog cholera virus and ruminant pestiviruses: the strain was found to be indistinguishable from that of other domestic pig isolates. the pathogenicity of the strain to domestic pigs was evaluated by infecting intranasally, intramuscularly and by contact 17 specific pathogen-free 6-week- and 12-week-old pigs. ... | 1992 | 1387299 |
| african swine fever virus infection in the iberian soft tick, ornithodoros (pavlovskyella) marocanus (acari: argasidae). | one thousand six hundred ornithodoros (pavlovskyella) marocanus velu larvae were fed on a pig infected with african swine fever virus (titer: 10(7.4) had50/ml), and 1,600 larvae were fed on an uninfected pig. ticks in each group were compared for mortality rates, mean time to death for ticks that died, mean time from feeding to either molting or eclosion, percentage of ticks that eclosed or molted, and the number of blood meals per nymph or instar. cumulative virus-induced mortality for all imma ... | 1992 | 1404269 |
| transcriptional analysis of multigene family 110 of african swine fever virus. | a transcriptional analysis of the 3.2-kb region of the african swine fever virus genome containing the five members of the multigene family 110 is presented. the mrnas corresponding to the genes studied have short leader sequences with no intervening aug codons before the translational start site, and their 3' ends map within a conserved sequence motif formed by a stretch of seven or more consecutive thymidylate residues. the possible role of this sequence as a signal for the 3'-end formation of ... | 1992 | 1404609 |
| african swine fever virus-induced dna polymerase is resistant to aphidicolin. | african swine fever virus (asfv) induces the synthesis of a virus-specific dna polymerase, which is inhibited by phosphonoacetic acid and cytosine arabinoside. in contrast to all other alpha-like dna polymerases of dna viruses, asfv-specific dna polymerase is resistant to aphidicolin. concentrations of the drug as high as 160 microm had no effect on virus production or plaquing efficiency. the resistance of asfv dna polymerase to aphidicolin was confirmed by analyzing the effect of the drug on v ... | 1992 | 1413523 |
| distribution of asfv antigens in pig tissues experimentally infected with two different spanish virus isolates. | lymph nodes, spleen, liver, lung and kidney obtained from pigs experimentally infected with two african swine fever virus (asfv) isolates of differing virulence were fixed by perfusion with glutaraldehyde and embedded in paraffin. an immunoperoxidase technique using a polyclonal anti-asfv serum was performed on tissue sections in order to detect asfv antigen. the distribution of asfv antigen in such infected organs is shown and the differences between both infections compared and discussed. mono ... | 1992 | 1414093 |
| localization of african swine fever viral antigen, swine igm, igg and c1q in lung and liver tissues of experimentally infected pigs. | an immunohistological study was carried out on lungs and livers of pigs experimentally infected with two different african swine fever virus (asfv) isolates. asfv antigen, swine immunoglobulins (igm and igg) and (clq) complement were demonstrated in both organs at different stages of infection. the asfv antigen was mainly found in mononuclear phagocytic system (mps) cells. immunoglobulins and complement were observed in plasma, infected and non-infected phagocytic cells and cell debris. these fi ... | 1992 | 1430349 |
| molecular characterisation of a dna ligase gene of the extremely thermophilic archaeon desulfurolobus ambivalens shows close phylogenetic relationship to eukaryotic ligases. | a 3382 bp fragment containing a gene for a dna ligase from the extremely thermophilic, acidophilic, and facultatively anaerobic archaeon (archaebacterium) desulfurolobus ambivalens was cloned and sequenced. the deduced amino acid sequence (600 amino acids, 67619 molecular weight) showed 30-34% sequence identity with the atp-dependent eucaryal (eukaryotic) dna ligases of schizosaccharomyces pombe, saccharomyces cerevisiae, the human dna ligase i, and with the vaccinia dna ligase. distant similari ... | 1992 | 1437556 |
| [polypeptides p14 and p31 of the african swine fever virus--early proteins located on the membrane of the infected cell]. | african swine fever virus polypeptides p14 and p31 are synthesized in the presence of phosphonacetic acid which inhibits viral dna replication, and therefore they are early viral proteins. these polypeptides were found to be localized on plasma membranes by immunofluorescence with monospecific antisera and monoclonal antibodies and by selective solubilization of infected cells. the p14-specific antibodies mediate complement-dependent cytolysis and antibody-dependent cytotoxicity of the cells inf ... | 1992 | 1441444 |