Publications

dna-dependent rna polymerase in african swine fever virus.		1980	7355576
a microtechnique for the titration for african swine fever virus.	african swine fever virus isolates were titrated in swine monocyte cultures established in microtitre trays. although technically simpler and less laborious than conventional tube assays the microtitration assay was less sensitive, but for routine and comparative titrations offers distinct advantages.	1980	7377975
experimental transmission of african swine fever virus by ornithodoros coriaceus, an argasid tick indigenous to the united states.	three ticks, indigenous to the united states, were assessed for their ability to maintain and transmit african swine fever virus (asfv). amblyomma americanum and a cajennense adults and nymphs maintained virus for 4 to 7 days after engorging on infected swine blood; however, virus was not carried through the subsequent molt of nymphs and it was not transmitted vertically to the eggs and larvae of the infected females. on refeeding of the ticks, infection was not transmitted to healthy swine. orn ...	1980	7406278
lymphocyte responses to african swine fever virus infection.	the immunological response of pigs infected with african swine fever virus was related to both quantitative and qualitative changes in the lymphocyte population. the cytolytic effect of the virus on lymphocytes caused a proportionally greater drop in b cell than in t cell numbers. a blastogenic test was developed to measure the appearance of specifically sensitised lymphocytes in the circulation. these appeared about 10 days after infection in animals infected with attenuated virus; pigs infecte ...	1980	7414064
[epizootiological prerequisites and results of use of live vaccines].	immunobiological action holds a firm position in veterinary legislation of the gdr with regard to the prevention and control of zoonoses, parasitoses, and other risk factors. here are some of the conditions which have to be satisfied for systematic and purpose-oriented application of live vaccines: (a) stringent procedures and rules for testing and acceptance of pharmaceutical preparations; (b) availability of scientifically founded concepts of application which have to be submitted for translat ...	1980	7416892
[requirements of rabbit-adapted swine fever vaccine].	studies were conducted into the demands made on both harmlessness and effectiveness of suvac, a swine fever vaccine prepared from strain "c", a rabbit-adapted chinese virus strain. the following findings were obtained: --the vaccine strain was attenuated to an extent by which it could be used without serum. --the vaccine was harmless even with immunodepressor action. its immunogenicity was good, and live weight growth of the animals was not impaired. --the vaccine was harmless to the foetuses. - ...	1980	7416897
[use of lapinized "c" vaccine as aerosol in immunoprophylaxis against swine fever].	lapinised vaccine, strain "c", was used on 3500 fattening pigs on two farms in experiments for aerogenic immunisation. two ordinary pigsties were modified for use as aerosol application chambers. a ussr-made disc-type aerosol generator, dag-2, was used for vaccine dispersion. piglets were allowed to be in contact with the aerosolic vaccine antigen for about 60 minutes. no deterioration in general health condition was observed, when longer contact periods were allowed. existing respiratory disord ...	1980	7416898
[immunologic abnormalities in pigs with hog cholera virus infection (author's transl)].	the effects of an acute hog cholera virus (hcv) infection upon immune functions of experimentally infected pis were studied. leukopenia was found to occur in both vaccinated and non-vaccinated infected animals but without any decrease in lymphocyte proportion. lymphocytes from infected pigs had an altered response to phytohemagglutinin (pha) as judged by an in vitro tritiated thymidine uptake of pha-stimulated lymphocyte cultures. the beginning of a secondary humoral immune response to lysozyme ...	1980	7436328
proteins specified by african swine fever virus. i. analysis of viral structural proteins and antigenic properties.	at least 28 polypeptides have been identified in intracellular virus, with molecular weights ranging from 11,500 to 243,000 daltons. by treatment with nonidet p-40 and 2-mercaptoethanol it is possible to obtain subviral particles that have lost some proteins and have a density in cscl of 1.31 g/cm3 which is higher than that of the complete virus (1.23 g/cm3). after addition of nacl the virus loses its major protein vp73 which indicates that it is localized in the viral envelope. cores obtained a ...	1980	7436740
experimental infection of warthos (phacochoerus aethiopicus) with african swine fever virus.	although there were no obvious signs of illness following experimental infection of young warthog with african swine fever virus, the animals developed viraemias between 10(2,4) and 10(3,6) hd50/ml within the first week of infection, and virus concentrations in a number of lymphatic tissues attained high levels (greater than or equal to 10(6) hd50/g). unlike in blood, and to some extent in the spleen, virus titres in lymph nodes did not decline appreciable during the 33-day observation period, s ...	1980	7454231
experimental transplacental transmission of hog cholera virus in pigs. i. virological and serological studies.		1980	7467990
experimental transplacental transmission of hog cholera virus in pigs. ii. immunopathological findings in the fetus.		1980	7467996
experimental study of a mild virulence strain of hog cholera: individual variations and horizontal transmission.		1980	7468006
[use and effectiveness of live vaccines in industrialized livestock production].	there is an inseparable correlation between higher livestock performance and animal health with many visible repercussions in terms of further intensification of livestock farming. this is the background against which immunobiological action is defined as a major element of all efforts which are undertaken for the purpose of ensuring high-stability and high-continuity and no-problem production. underlined in this paper is the great role played by legal provisions for immunisation concepts as wel ...	1980	6251768
possible factors influencing the immunoglobulin g concentration in swine colostrum.	the immunoglobulin (ig) g concentration in swine colostrum was determined by the single radial immunodiffusion method, using 157 samples collected from farm-raised sows in the yamaguchi prefecture of japan during 1976 and 1977. the mean igg value was 53.03 mg/ml, and the maximum and minimum values were 101.39 mg/ml and 11.74 mg/ml, respectively. the amount of igg varied greatly among sows. to clarify the possible factors influencing the amount of igg in colostrum, the following items were survey ...	1980	6254410
analysis of soluble bovine viral diarrhoea virus antigens and serological relationship to virus structural glycoproteins.		1980	6261488
proteins specified by african swine fever virus. ii. analysis of proteins in infected cells and antigenic properties.	infection of ms cells with african swine fever virus (asfv) produces inhibition of protein synthesis which is detectable from 4.5 hours after infection. at least 34 viral polypeptides have been indentified with molecular weights ranging between 9500 and 243,000 daltons. three of these proteins show affinity for the cell nucleus and nine are in both the nuclear and cytoplasmic fractions. ten early proteins were found, and most of the structural proteins were late proteins. most of the proteins ar ...	1980	6776940
effect of a hog cholera vaccine strain on the bactericidal activity of porcine alveolar macrophages.		1980	6794120
persistent hog cholera infection detected during virulence typing of 135 field isolates.	during the hog cholera (hc) eradication program in the united states, 135 field isolates were characterized by inoculation into specific-pathogen-free pigs. this gave origin to the classification of 61 (45%) as high virulent, 37 (27%) as low virulent, 29 (22%) as avirulent or immunizing, and 8 (6%) as capable of causing persistent infection. the persistent infections caused by the eight isolates were of long durtion, lasting in one instance to 152 days. the persistently infected pigs remained re ...	1980	6449165
[control of european (classical) hog cholera].		1980	6758195
western hemisphere isolates of african swine fever virus: asymptomatic carriers and resistance to challenge inoculation.	convalescent clinically normal pigs were tested for the persistence of african swine fever (asf) infection. one group of pigs was examined 135 days after inoculation with a brazilian isolate and a 2nd group was examined 110 days after inoculation with a dominican republic isolate. susceptible pigs exposed by contact to these groups remained clinically normal. these contact pigs plus 2 more pigs added to each group developed asf after being fed and inoculated with tissues collected from recovered ...	1980	7212418
sedimentation coefficient of african swine fever virus.	the sedimentation coefficient of the infective unit of african swine fever in tissue culture harvest fluids was measured in a preparative ultracentrifuge. the boundary locator method used also permitted making an estimate of heterogeneity. the sedimentation coefficient ranged from 3,000 to 8,000 svedberg units, representing many classes of infective particles. electron microscopy on culture fluids from infected cells showed many kinds of virus-containing units. sucrose-cscl gradient centrifugati ...	1980	7212420
atypical hog cholera infection: viral isolation and clinical study of in utero transmission.	sows in different stages of pregnancy were inoculated with a low-virulence hog cholera strain. clinical signs of disease were not observed in the sows during pregnancy, but most of their pigs were splaylegged and had nervous disorders; perinatal mortality was high. a few pigs from sows that were inoculated during the 1st trimester of pregnancy survived and remained inapparent carriers of virus, without developing antibodies. seemingly, these pigs were immunotolerant. virus was transmitted from i ...	1980	7212435
experimental transplacental transmission of hog cholera virus in pigs. iii. histopathological findings in the fetus.		1980	7223180
[one of aberrant organisms isolated from swine kidney culture cells (author's transl)].		1980	7304099
[study on hog cholera-sine erysipelas combined liver vaccine. i. experimental preparation of combined live vaccine (author's transl)].		1980	7304106
[study on hog cholera swine erysipelas combined live vaccine. -ii. indoor test of vaccination (author's transl)].		1980	7304108
[hog cholera diagnosis: an improved technique of seroneutralization based on use of a cytolytic virus strain in microplate (author's transl)].	an improved technique for the detection of hog cholera virus (hcv) neutralizing antibodies is described, in which running of the test is greatly facilitated by use of a cytolytic strain of hcv. this strain was isolated from persistently infected ib-rs 2, and was shown to induce a distinct cytopathic effect in several pig kidney cell lines (laude, 1978). for the assay, serum samples at 1 : 10 are diluted serially twofold in disposable microplates, then 1 x 10(4) pfu of the virus-stock are added i ...	1980	7259033
replication of african swine fever virus in cell cultures.	infection-specific, nonstructural, african swine fever virus antigens, as visualized by the immunofluorescence technique, appeared as fine stipplings, evenly distributed in the cytoplasm and nucleus of vero cells and in monocytes by postinoculation hour (pih) 3. cytoplasmic inclusion bodies (ib) appeared at pih 4 and continued to increase in size up to pih 8. the viral dna was solely synthesized within the ib of infected monocytes, as evidenced by an autoradiographic chase experiment; maximum sy ...	1980	7004279
enzyme linked immunoassay and fluorescent antibody techniques in the diagnosis of viral diseases using staphylococcal protein-a instead of anti-gamma-globulins.	staphylococcal protein-a (spa) is known to interact with the crystallizable fragment (fc) of igg molecules from several species. in the present study, spa coupled to either fluorescein isothiocyanate (fitc) or peroxidase was used in place of antisera to igg for the fluorescent antibody (fa) techniques and the enzyme linked immunoassay (elisa). the spa conjugates produced low background staining when applied in these techniques, and provide a rapid, highly specific and sensitive means for the ide ...	1980	15612263
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
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
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
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
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
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
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
[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
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
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
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
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
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
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
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
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
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
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
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
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
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
[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
[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
[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 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
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
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
[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