Publications

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
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
photographic defocusing: a means to render recognizable line traced models of negatively stained biological specimens.	a simple method of obtaining analogue images from traced models of biological specimens is presented. it consists of the photographic defocusing of traced models and it is illustrated with negatively stained cylindrical forms of the asfv; the black lines of the trace in the model correspond to the negative stain surrounding the viral morphological subunits as seen in the electron micrograph. the photographic defocusing is the means by which the traced model is filtered and is used to introduce g ...	1981	7241589
[use of the hemadsorption method to demonstrate the african swine fever virus in angola].	attempts were made to modify the hemadsorption method used in the demonstration of the african swine fever virus. use was made of fourteen strains of the virus with known hemadsorption properties and infectious titers, which were replicated in leukocyte cultures of swine blood, in three variants: (a) at direct infection of the cultures without changing the medium; (b) at infecting with changing the medium and adding erythrocytes to the new medium; and (c) infecting the cultures with changing the ...	1981	7303482
induced african swine fever in feral pigs.	feral pigs trapped in florida were exposed by intranasal/oral inoculation or contact to african swine fever virus isolants from the iberian peninsula and the dominican republic. all exposed pigs became sick and died or were killed after becoming moribund. necropsy revealed lesions typical of african swine fever, but several pigs had marked hemorrhage surrounding the kidneys or rectum or in the gastric, hepatic, or ventral abdominal region that, in the field, might have suggested trauma or poison ...	1981	7309606
african swine fever virus (malta/78) in pigs.		1981	7345110
field evaluation of enzyme-linked immunosorbent assay for detection of antibody to african swine fever virus.	the enzyme-linked immunosorbent assay (elisa) for detection of antibodies to african swine fever virus was evaluated under field conditions in the dominican republic. a total of 3,402 swine serums were tested by elisa. all elisa-positive serums (n = 224) and 426 of 2,760 elisa-negative serums were retested by indirect immunofluorescence (iif). there were no antibodies to asf virus detected by iif in elisa-negative serums. by iif, antibodies were detected in only a small portion of the elisa-posi ...	1981	7027849
african swine fever: a reassessment.		1981	7034503
a reliable enzyme linked immunosorbent assay for african swine fever using the major structural protein as antigenic reagent.		1981	7034688
polyadenylation, methylation, and capping of the rna synthesized in vitro by african swine fever virus.		1981	6168100
leukocyte-dependent platelet vasoactive amine release and immune complex deposition in african swine fever.	fifteen pigs were inoculated with african swine fever virus in a study of the pathogenesis of the disease. all pigs surviving the first two weeks developed high circulating antibody titers against african swine fever virus and persistent viremia. hemolytic complement levels declined to 50 to 70 hemolytic complement 50 (ch50) units/ml from mean preinoculation levels of 120 ch50 units/ml. immune deposits consisting of african swine fever antigen, host immunoglobulin g, and native c3 were found in ...	1981	6170156
nucleoside triphosphate phosphohydrolase activities in african swine fever virus.	african swine fever virus contains nucleoside triphosphate phosphohydrolase activity which releases 32p phosphate from gamma-32p atp at a rate of about 1 mumol/h mg of virus protein. the hydrolase activity is slightly stimulated by adding nucleic acids to the reaction mixture and under conditions of rna synthesis. a study of the rate of atp hydrolysis at different concentrations of atp suggests the existence of two phosphohydrolase activities with apparent km values of about 0.04 and 1 mm.	1981	6271106
lymphocyte function and cell-mediated immunity in pigs with experimentally induced african swine fever.	twenty-five pigs inoculated with african swine fever virus were studied for the development of changes in lymphocyte numbers and function. the results indicated that lymphopenia and decreased percentage of circulating t-lymphocytes occurred as early as 7 days after the pigs were inoculated. these were accompanied by depressed lymphocyte function, as measured by mitogen- or antigen-induced blastogenesis. there were proportionately greater decreases in t-lymphocyte numbers and function than were f ...	1981	6975049
african swine fever virus dna: restriction endonuclease cleavage patterns of wild-type, vero cell-adapted and plaque-purified virus.	dna from african swine fever (asf) virus was isolated and was characterized by two restriction enzymes, smai and ecori. although both enzymes can distinguish vero cell-adapted asf isolates by characteristic restriction endonuclease cleavage patterns, all asf isolates examined exhibited a high degree of similarity, as measured by co-migration of most of the dna fragments. the molecular weight of asf dna, based on size estimates of dna fragments from cleavage patterns, ranged from 93 x 10(6) to 10 ...	1982	6296285
new method of antibody detection by indirect immunoperoxidase plaque staining for serodiagnosis of african swine fever.	an indirect immunoperoxidase plaque-staining method was developed for detecting antibody to african swine fever virus infection. in both sensitivity and specificity, the test was comparable to indirect immunofluorescence. because it has all of the desirable features of the indirect immunofluorescence test and may also be readily used for testing large numbers of sera, the indirect immunoperoxidase plaque-staining method can be used as a single and final serodiagnostic test in a large-scale surve ...	1982	6185528
effect of african swine fever on lymphocyte mitogenesis.	the effect of african swine fever virus replication on t and b lymphocytes was studied by mitogen-driven assays. live attenuated isolates caused a marked suppressive effect which was dose- and time-dependent. this effect appeared to be mediated through a monokine. live virulent isolates enhanced lymphocyte mitogenesis in most cases, with increased [3h]-thymidine uptake by t cells and increased ig secretion by b cells. killed preparation had no effect. these results are discussed in the light of ...	1982	6210625
inactivation of african swine fever virus in tissues by gamma radiation.		1982	7046538
complement-mediated lysis of african swine fever virus-infected cells.	using an homologous pig system, th lysis of african swine fever virus-infected cells by antibody and complement was investigated. the optimal conditions necessary for lysis are described, and it was found that the system was unique amongst reported virus infections in that infected cells were lysed by the classical complement pathway and not the alternative pathway. development of antibody capable of initiating complement-mediated lysis was relatively late in the infected pig, although functiona ...	1982	7076281
production and titration of african swine fever virus in porcine alveolar macrophages.	the broncho-alveolar lavage of a pig (20-40 kg) contains about 1.6 x 10(9) alveolar cells, half of which were macrophages. the number of cells in the lavage of bacille calmette guerin (bcg)-treated pigs increased about 4-fold. both african swine fever virus-infected porcine alveolar macrophages and blood monocytes produced about 1000 hemadsorption units/cell, a value 10-fold larger than that obtained in virus-infected vero cells. porcine alveolar cells could be stored frozen and, after thawing, ...	1982	7085838
the immunological response of pigs and guinea pigs to antigens of african swine fever virus.	pigs vaccinated with glutaraldehyde-fixed alveolar macrophages (am) infected with african swine fever virus (asfv) had an accelerated serological response after subsequent challenge and a slight reduction in levels of viraemia. vaccination of pigs with detergent-treated infected am produced no detectable serological response and no protection against homologous challenge. guinea pigs were vaccinated with glutaraldehyde-fixed asfv-infected cells, detergent-treated infected cells, detergent-treate ...	1982	7165511
proteins specified by african swine fever virus. iv. glycoproteins and phosphoproteins.	african swine fever virus infected ms cells labeled with radioactive 14c-amino acids, 32pi or [3h]-glucosamine were examined by high resolution sodium dodecylsulfate polyacrylamide gel electrophoresis and showed 43 infected cell polypeptides. twenty-one of these proteins were present in the nuclear fraction of infected cells. at least 22 of the infected cell polypeptides induced antibodies during natural infections in swine. the pattern of infected cell polypeptides modified by incorporation of ...	1983	6416226
investigation of porcine natural-killer cell activity with reference to african swine-fever virus infection.	the natural killing of the human myeloid leukaemia cell line by pig mononuclear cells was investigated in an 18 hr assay; the most active natural-killer (nk) effectors were those cells not adhering to nylon-wool columns or rosetting with sheep red blood cells. mononuclear cells cultured in the presence of african swine-fever virus maintained nk activity. pigs infected with african swine-fever virus exhibited a suppressed nk activity, possibly due to the sensitivity of nk cells to increased tempe ...	1983	6575959
effector mechanisms in the pig. antibody-dependent cellular cytolysis of african swine fever virus infected cells.	antibody dependent cellular cytolysis (adcc) against african swine fever virus infected nucleated cells was investigated in a porcine system. of the peripheral blood components examined, only neutrophils acted as effectors. lymph node derived cells displayed no adcc activity. in vitro yield reduction assays suggested that neutrophil mediated adcc may play a role in recovery from african swine fever virus infection.	1983	6622849
effect of rifamycin derivatives and coumermycin a1 on in vitro rna synthesis by african swine fever virus. brief report.	several rifamycin derivatives inhibited the dna-dependent rna polymerase of african swine fever (asf) virus particles. the inhibition was similar to that found with vaccinia virus rna polymerase. coumermycin a1, an inhibitor of type ii dna topoisomerases, inhibited strongly rna synthesis in vitro by asf virus particles. this suggests that transcription of asf virus dna requires a dna topoisomerase.	1983	6625887
could aids agent be a new variant of african swine fever virus?		1983	6132234
african swine fever virus antibody not found in aids patients.		1983	6133121
aids and african swine fever.		1983	6134121
aids and african swine fever.		1983	6134949
african swine fever virus. brief review.		1983	6307224
interactions of porcine alveolar macrophages and bone marrow cells with african swine fever virus and virus-infected cells.	virus yields from porcine alveolar macrophages (am) infected with african swine fever virus (asfv) were greater and were achieved more rapidly, when inoculated at a high multiplicity of infection (moi) than at low moi. the difference was related to a lower percentage of cells becoming infected after low moi inoculation. the reduced yields after low moi were not caused by prolongation of the culture time, by bacterial endotoxins or by production of inhibitory substances by infected am. virus-infe ...	1983	6868333
molecular cloning of african swine fever virus dna.	african swine fever virus dna (about 170 kbp) was cleaved with the restriction endonuclease ecori and most of the resulting 31 fragments were cloned in either the phage vector lambda wes lambda b or the plasmid pbr325. three fragments were not cloned in those vectors, the largest fragment ecori-a (21.2 kbp) and the two crosslinked terminal fragments, ecori-k' and d'. endonuclease sali cut fragment ecori-a into three pieces which were cloned in plasmid pbr322. the two terminal ecori fragments wer ...	1984	6324451
restriction site map of african swine fever virus dna.	treatment of african swine fever virus dna (about 170 kbp) with the restriction endonucleases sali, ecori, kpni, pvui, and smai yielded 14, 31, 17, 13, and 11 fragments, respectively. the order of the restriction fragments produced by each nuclease was established by identifying the crosslinked ecori and sali terminal fragments and then finding overlapping fragments. the five restriction fragment maps were integrated into a single map by locating sali, kpni, pvui, and smai sites in cloned ecori ...	1984	6324452
terminal and internal inverted repetitions in african swine fever virus dna.	an electron microscopic analysis of the heteroduplexes formed by reannealing denatured terminal restriction fragments of african swine fever (asf) virus dna showed y-shaped molecules with a 2.1-kilobase-pair-long double-stranded tail and two single-stranded arms. this indicated that asf virus dna has terminal inverted repetitions with a length of 2.1 kbp. in addition, under less restrictive hybridization conditions, most of the heteroduplexes showed a 0.13 kbp-long internal double-stranded regio ...	1984	6324453
foreign animal disease agent survival in animal products: recent developments.		1984	6327587
speculations on the viral etiology of acquired immune deficiency syndrome and kaposi's sarcoma.	the acquired immune deficiency syndrome (aids) appeared in the united states in late 1978 and has spread at an epidemic rate through the four major coastal cities of this country. the disease appears to show the same epidemiologic distribution as hepatitis b virus infection, and for this reason, most investigators feel that this new disease is caused by a blood-borne sexually transmitted virus. a number of viral agents have been suggested as the cause of aids, but to date, no virus has been cons ...	1984	6330223
extraction of viral dna from erythrocytes of swine with acute african swine fever.	the preparation of wild-type african swine fever (asf) virus dna from small amounts of viremic blood from acutely febrile pigs is outlined. the extracted dna is viral and not host-cell dna, because of specific homology with cell culture grown and purified asf virus and because no dna bands are obtained with an equal amount of nonviremic pig blood. thus, in the absence of suitable serologic methods for strain identification, it is now possible to catalogue wild-type isolates by characteristic dna ...	1984	6331232
porcine leukocyte cellular subsets sensitive to african swine fever virus in vitro.	african swine fever virus infected most, if not all, of the macrophages (monocytes) and ca. 4% of the polymorphonuclear leukocytes from porcine peripheral blood. b and t lymphocytes, either resting or stimulated with phytohemagglutinin, lipopolysaccharide, or pokeweed mitogen, were not susceptible to the virus. all of the mitogens used inhibited african swine fever multiplication in susceptible cells. the number of virus passages in vitro and the virulence degree of the virus did not affect the ...	1984	6384555
general morphology and capsid fine structure of african swine fever virus particles.	the structure of african swine fever virus particles has been examined by electron microscopy. the analysis of virions prepared by negative staining, thin sectioning, and freeze-drying and shadowing showed that the virus particle was composed of several concentric structures with an overall icosahedral shape. the inner region of the virus particles was a nucleoid that was surrounded by a membrane covered by the capsid. the capsid had side-to-side dimensions of 172 to 191 nm and was built up by c ...	1984	6695498
virulence in african swine fever: its measurement and implications.	a method of measuring and expressing the virulence of african swine fever virus in numerical terms was developed. seventeen viruses (13 hemadsorbing and 4 nonhemadsorbing) were tested and classified into 3 groups: highly infectious and highly virulent, highly infectious and moderately virulent, and slightly infectious and slightly virulent. this classification was based on the number of 50% hemadsorption unit (ha50) or tcid50 required to produce 1 ld50 for swine, the number of ha50 or tcid50 req ...	1984	6711963
clinical and immunologic responses of pigs to african swine fever virus isolated from the western hemisphere.	pigs in the united states were exposed to african swine fever (asf) virus isolated from pigs in brazil and the dominican republic. the former were examined for clinical response, lesions, viremia, and antibody response. sequential blood samples were tested for the presence of asf virus by the hemadsorption test (in swine buffy coat cell culture) and for antibody to asf virus by the enzyme-linked immunosorbent assay. the incubation period was 3 to 5 days; inoculated pigs had fever for 8 to 16 day ...	1984	6731983
characterization of african swine fever virus antigenic proteins by immunoprecipitation.	african swine fever virus is a large, complex virion in which numerous proteins have been identified by biochemical techniques. few of these proteins have been shown to react with antibodies from recovered swine, leading to speculation that the immunological unreactivity of some viral proteins might explain the inability of immune sera from surviving animals to neutralize the virus. we used immunoprecipitation of radiolabeled viral proteins to examine these sera in more detail. gradient sodium d ...	1984	6732509
considerations in searching for the cause of aids.		1984	6598303
coagulation changes in african swine fever virus infection.	pigs were infected with highly virulent (tengani '62), with moderately virulent (dr '79) african swine fever (asf) virus, or with virulent hog cholera (hc) virus. changes in platelet counts, selected coagulation assays and concentrations of factor viii-related antigen (viiir:ag) were monitored. permeability of aortic endothelium was studied after the injection of evan's blue dye on various days after infection with dr '79 asf virus. virulent asf virus caused prolongation of the activated partial ...	1984	6441489
quantitative aspects of the transmission of african swine fever.	the contagiousness of pigs during different stages of infection with african swine fever virus was assessed by measuring the amount of virus excreted and the amounts of virus in the blood and other tissues, as well as determining the infectious dose of the virus by various routes. the virus was present in substantial amounts in secretions and excretions of acutely infected pigs for only 7 to 10 days after the onset of fever and was present in the greatest amount in the feces. virus persisted in ...	1984	6476567
swine diseases transmissible with artificial insemination.	the transport of fresh and frozen semen to be used for artificial insemination creates a mode of disease transmission between farms. normally, semen contains a number of nonpathogenic bacterial contaminants; however, excessive bacterial contamination can result in infertile matings. contamination with a known pathogen, eg, brucella suis, could initiate a serious outbreak of disease in a recipient herd. methods to minimize bacterial contamination of semen include sanitary collecting and processin ...	1984	6090372
antiviral action of 5-amino-2-(2-dimethyl-aminoethyl)benzo-[de]-isoquinolin-1,3-dion e.	a newly synthesized imide derivative of 3-nitro-1,8-naphthalic acid, 5-amino-2-(2-dimethylaminoethyl)benzo-[de]-isoquinolin-1,3-dione (designated m-fa-142), was tested on chick embryo cells against herpes simplex virus type 1 (hsv-1) and vaccinia virus (vv), and on vero cells against african swine fever virus (asfv). at a concentration of 4 micrograms/ml the drug inhibited vv replication by about one order of magnitude, and that of hsv-1 by about three orders of magnitude. a minor effect was sho ...	1984	6091540
cytotoxic lymphocytes induced by african swine fever infection.	the generation of lymphocytes cytotoxic to african swine fever virus infected testis cells during in vivo infection is described. peripheral blood lymphocytes from 16 pigs developed cytotoxicity seven to eight days after infection but the lysis was not restricted to autologous cells.	1984	6095388
[viral etiologies of aids: facts and hypotheses].	all the epidemiological features suggest that the acquired immunodeficiency syndrome (aids) is caused by a single transmissible agent and surely a virus. first, cytomegalovirus, epstein-barr virus and hepatitis b virus have been proposed as possible etiological agents of aids. a direct link between ubiquitous viruses and the occurrence of the disease has been discarded. at present time, etiological researches provide evidence that retroviruses are the best candidates for the etiology of aids. th ...	1984	6095408
abortion in sows experimentally infected with african swine fever virus: clinical features.	thirteen sows between 38 and 92 days of pregnancy were exposed oronasally to african swine fever virus (1979 dominican republic isolate) to determine whether infection would affect their reproductive performance. abortions occurred in sows in all stages of pregnancy. of 11 sows, 7 aborted 5 to 8 (6.1 +/- 0.90) days after inoculation or 0 to 3 (1.4 +/- 0.98) days after fever development. abortions occurred soon after clinical signs of infection first developed and viremia titers peaked. swelling ...	1984	24049897
morphological study on the entry of african swine fever virus into cells.	the early interactions between african swine fever virus (asfv) and monkey kidney cells in culture, and the effect of chloroquine were studied by electron microscopy. our results indicate that asfv uptake occurs by endocytosis: after attachment to the cell surface, the virions were seen in coated pits and were internalized by endocytosis in endosomes and finally in lysosomes. virions in coated vesicles were never seen. all these steps were completed in about 15 min. direct penetration of viruses ...	1985	2937495
an immunological approach to vaccines against african swine fever virus.	until recently there were no published reports of any immunological mechanism which could curtail the replication of african swine fever virus (asfv). we have now described three such mechanisms--complement dependent lysis, antibody dependent cellular cytotoxicity and cytotoxic t lymphocytes. this paper discusses the likely role which each might play during asfv infection and indicates where this research might help with a disease where no effective vaccine is available.	1985	3873757
monoclonal antibodies specific for african swine fever virus proteins.	we have obtained 60 stable hybridomas which produced immunoglobulins that recognized 12 proteins from african swine fever virus particles and african swine fever virus-infected cells. most of the monoclonal antibodies were specific for the three major structural proteins p150, p72, and p12. the specificity of some monoclonal antibodies for the structural proteins p150 and p37 and the nonstructural proteins p220 and p60 indicated that proteins p150 and p220 are antigenically related to proteins p ...	1985	3882998
comparative ultrastructure of iridoviridae.		1985	3893905
african swine fever virus.		1985	3893908
the epidemiology of african swine fever: the role of free-living hosts in africa.	the known distribution of african swine fever (asf) virus in africa is reviewed in relation to the distributions of its free-living hosts as are the infection rates of these species in different localities in southern africa. mechanisms by which asf virus is maintained in its sylvatic state and ways in which the infection may enter domestic pig populations are discussed.	1985	3911134
purification and properties of african swine fever virus.	we describe a method for african swine fever (asf) virus purification based on equilibrium centrifugation in percoll density gradients of extracellular virions produced in infected vero cells that yielded about 15 +/- 9% recovery of the starting infectious virus particles. the purified virus preparations were essentially free of a host membrane fraction (vesicles) that could not be separated from the virus by previously described purification methods. the purified virus sedimented as a single co ...	1985	3989907
effect of chloroquine on african swine fever virus infection.	when present during the whole infective cycle, the lysosomotropic drug, chloroquine, inhibited cytopathic changes and production of african swine fever virus (asfv) in vero cells. this inhibition decreased when the drug was added from 1 h to 4 h after infection. chloroquine had no effect on the virus nor on viral adsorption and internalization. electron microscopy showed that, in the presence of the drug, the virions were retained in large vacuoles having a lysosomal appearance. this inhibition ...	1985	3998709
the role of antibody in protection against african swine fever virus.	intraperitoneal immunization of pigs with anti-african swine fever virus (asfv) antibody protected them against the effects of challenge with asfv. this protection, which was exemplified by a reduction in pyrexia and viraemia plus an increased survival time, appeared to be mediated through the effects of complement-dependent antibody-mediated cytotoxicity (cdac) or antibody dependent cell mediated cytotoxicity (adcc). experiments suggested that the reduction in viraemia was associated with compl ...	1985	4035978
monoclonal antibodies against african swine fever viral antigens.	monoclonal antibodies specific for african swine fever (asf) viral proteins of 14, 32, 73, 174, and 240 kda were produced and characterized. immunoelectron microscopy detected the 73 kda but not the 14-, 32-, or 240-kda proteins at the surface of the virion. the 32-kda protein was detected by radioimmunoassay 2 hr after infection of porcine monocytes and vero cells, was detected in the seven widely divergent asfv isolates tested, and stained brilliantly virus-infected cells in indirect immunoflu ...	1985	4060578
mechanism of thrombocytopenia in african swine fever.	pigs were inoculated with an african swine fever (asf) isolate of moderate virulence, and the changes in the number of circulating blood platelets during infection were correlated with the appearance of antiviral antibody and fluctuations in total plasma hemolytic complement concentrations. thrombocytopenia was detected by postinoculation days (pid) 7 and 8, and antiviral antibody was detected by pid 7, using an indirect immunofluorescence technique. the total hemolytic complement concentration ...	1985	4062007
polypeptides and structure of african swine fever virus.	extracellular and intracellular african swine fever virus (asfv) was purified using a two-phase aqueous polymer system. both the structure of the virus and the polypeptides present during the purification procedure were studied. after peg/dextran phase separation and centrifugation through 20% (w/v) ficoll, 79% of input infectivity was recovered as semi-purified virus. the density of the virus after equilibrium centrifugation in sucrose was 1.19 g/ml. the envelope of the virion consisting of a u ...	1985	4072397
experimental transmission of african swine fever virus by ornithodoros savignyi (audouin).	the 'sand tampan', ornithodoros savignyi, is susceptible to oral infection with african swine fever (asf) virus in the laboratory. infected ticks can transmit the virus transstadially and are able to maintain it for at least 106 days. transmission of asf virus by infected ticks to healthy pigs was achieved on five separate occasions between 50 and 106 days after infection. pigs infected in this way developed typical acute african swine fever. the distribution of o savignyi in africa suggests tha ...	1985	4081341
diversity of african swine fever virus.	an african swine fever virus is an heterogeneous population, consisting of clones having different biological characteristics in respect to hemadsorption, virulence, infectivity, plaque size, and antigenic determinants. the following observations were made: nonhemadsorbing virus (nhv) have been segregated from field isolates from haiti (ht-1) and a bone marrow- and buffy coat-passaged portuguese isolate (l'60bm89bc1) and appear as a major, minor, or equal mixture with hemadsorbing viruses in the ...	1985	2581483
monoclonal antibodies of african swine fever virus: antigenic differences among field virus isolates and viruses passaged in cell culture.	an analysis of the binding properties of a collection of monoclonal antibodies to african swine fever virus particles showed that virus field isolates passaged in porcine macrophages changed antigenically more than a strain of a cell-adapted virus passaged in vero cells. from seven clones isolated from the spleen of a field-infected pig, we found four clones that had the same antigenic properties, one clone that had large changes in proteins p150 and p27 and small changes in proteins p37 and p14 ...	1986	2422393
application of prpel2 plasmid to detect african swine fever virus by dna-dna hybridization. brief report.	a diagnostic assay has been developed to detect african swine fever virus in field samples. it is based on the use of 32p-dna from prpel2 plasmid as a hybridization probe. this plasmid contains essentially the h-clai dna fragment from the spain-70 strain of african swine fever virus.	1986	3942504
establishment of a vero cell line persistently infected with african swine fever virus.	a vero cell line persistently infected with african swine fever virus was established by infecting the cells in the presence of 10 mm nh4cl (vero-p cell line). the virus derived from the vero-p cultures infected vero cells, and virus titers were comparable to those obtained in vero cells acutely infected with african swine fever virus. the structural proteins of the virus from vero-p cells were similar to those of the virus produced in lytic infections. virus production was low when the vero-p c ...	1986	3701926
inactivation and inhibition of african swine fever virus by monoolein, monolinolein, and gamma-linolenyl alcohol. brief report.	monoolein, monolinolein and (most strongly) gamma-linolenyl alcohol inactivate asf virus and inhibit its replication in vero cells at 25 micrograms/ml while at 10 micrograms/ml no inactivation occurs but inhibition of replication in tissue culture is observed. this suggests two possibly different action mechanisms.	1986	3707358
transcription and translation maps of african swine fever virus.	a transcription map of african swine fever (asf) virus dna was obtained by hybridization of 32p-labeled early and late rnas synthesized in vero cells infected with asf virus to dot-blots containing cloned restriction fragments spanning the viral genome. early rnas synthesized in infected cells in the presence of protein or dna synthesis inhibitors hybridized preferentially to four regions in the genome, with coordinates e1 (0-51.9 kbp), e3 (63.7-75.2 kbp), e5 (100.1-111.6 kbp), and e7 (150-170 k ...	1986	3716203
glycosylated components of african swine fever virus particles.	extracellular african swine fever (asf) virus particles were specifically agglutinated by several lectins, suggesting the presence of surface glycosylated component(s) containing at least glucose, mannose, or both; galactose, n-acetylgalactosamine, or both; n-acetylneuraminic acid and n-acetylglucosamine, but not fucose. when virions were purified from infected vero cells labeled with [14c]glucosamine, [14c]galactose and analyzed by polyacrylamide gel electrophoresis, no major structural glycopr ...	1986	3716204
new agents active against african swine fever virus.	actinobolin, atropine, carrageenan, megalomycin c, suramin, and tetracenomycin c were tested for their activity against african swine fever virus replication. both viral inhibitory potency and cytotoxicity were investigated. megalomycin c, suramin, atropine, and carrageenan exhibited significant activity. megalomycin c was the most active of the four agents with respect to the concentration of compound that blocked the formation of infectious virus by 50%. suramin was the next most active agent ...	1986	3717934
african swine fever virus gene expression in infected vero cells.	polypeptides synthesized in vero cells infected with african swine fever virus (asfv) can be divided into early and late classes on the basis of their sensitivity to cytosine arabinoside. as asfv does not inhibit cell protein synthesis until late in infection, immunoprecipitation was used to identify virus-specific polypeptides. eighteen early and 15 late polypeptides were detected by polyacrylamide gel electrophoresis. early polypeptides can be further divided into those which are transiently e ...	1986	3723111
inhibition of african swine fever infection in the presence of immune sera in vivo and in vitro.	in assay cultures, sera from african swine fever convalescent pigs inhibited infection by homologous african swine fever virus. the infection-inhibition capacity did not correspond with the virus-neutralizing capacity. the serum did not prevent infection by heterologous virulent viruses. sera from pigs challenge inoculated with the homologous virulent virus and later with a heterologous virulent virus inhibited the infection by different heterologous virulent viruses. these sera did not interfer ...	1986	3729125
neutralization of african swine fever virus by sera from african swine fever-resistant pigs.	sera from african swine fever-resistant pigs with infection-inhibitory activity decreased virus replication in infected porcine buffy coat cultures. this same effect was observed even after virus was adsorbed. the infection-inhibition was not reversed by removing the immune serum from the assay cultures. reduction of african swine fever virus replication by immune sera was demonstrated by fluorescent focus assay on ms cell line cultures. virus-neutralization tests showed a persistent fraction of ...	1986	3752695
a novel selective broad-spectrum anti-dna virus agent.	a new compound has been found, (s)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine ((s)-hpmpa), that has potent and selective activity against a broad spectrum of dna viruses, including herpes simplex virus (types 1 and 2); varicella zoster virus; thymidine kinase-deficient (tk-) mutants of herpes simplex and varicella zoster virus; human cytomegalovirus; phocid, simian, suid, bovid and equid herpesviruses; african swine fever virus; vaccinia virus; and human adenoviruses. it is also active again ...	1986	3762696
african swine fever. i. morphological changes and virus replication in blood platelets of pigs infected with virulent haemadsorbing and non-haemadsorbing isolates.	replicating and mature viral particles were detected with the transmission electron microscope in blood platelets of pigs infected with virulent haemadsorbing and non-haemadsorbing african swine fever virus isolates. although platelet numbers decreased terminally in infected pigs, the most noticeable morphological damage to these cells apparent in the last 2 days of the disease included cytoplasmic swelling, vacuolation, fragmentation and loss of dense granules.	1986	3763165
hairpin loop structure of african swine fever virus dna.	the ends of african swine fever virus genome are formed by a 37 nucleotide-long hairpin loop composed, almost entirely, of incompletely paired a and t residues. the loops at each dna end were present in two equimolar forms that, when compared in opposite polarities, were inverted and complementary (flip-flop), as in the case of poxvirus dna. the hairpin loops of african swine fever and vaccinia virus dnas had no homology, but both dnas had a 16 nucleotide-long sequence, close to the hairpin loop ...	1986	3763393
single-stranded deoxyribonucleic acid nuclease induced by african swine fever virus and associated to the virion.	infection of vero cells with african swine fever (asf) virus resulted in a marked increase of dnase active on single-stranded dna (ss-dnase). no increase was observed for double-stranded dna-specific nuclease activity. in contrast to uninfected cell ss-dnase, which has a ph optimum at ph range 8.5-9, virus-induced ss-dnase is most active at ph 7. differences in sensitivity to several ions and other modifications of the reaction mixture and considerable difference in reaction kinetics suggest tha ...	1986	3776099
african swine fever virus-induced polypeptides in vero cells.	african swine fever virus induces in vero cells 81 acid and 14 basic polypeptides which account for most of the information content of the virus dna. the kinetics and the cytosine arabinoside sensitivity of the synthesis of the virus-induced polypeptides showed the existence of three classes of proteins, two early and one late. most of the early proteins were synthesized along the whole replication cycle, but the synthesis of some of the early proteins was switched-off after virus dna replicatio ...	1986	3776350
african swine fever virus and aids.		1986	2869298
african swine fever and aids.		1986	2873310
aids and african swine fever virus.		1986	2876270
localization of structural proteins in african swine fever virus particles by immunoelectron microscopy.	seven african swine fever virus structural proteins were localized in the virion by immunoelectron microscopy. african swine fever virus-infected cells were incubated, before or after embedding and thin sectioning, with monoclonal antibodies specific for different structural proteins, and after labeling with protein a-gold complexes, the samples were examined in the electron microscope. proteins p14 and p24 were found in the external region of the virion, proteins p12, p72, p17, and p37 were fou ...	1986	3517383
[african swine fever in the netherlands].	african swine fever (asf) was diagnosed for the first time in the netherlands on a farm near the hague, illegally feeding swill from hospitals, hotels and restaurants. laboratory diagnosis was based initially on the indirect immunofluorescence test (ift) and the immunoperoxidase monolayer assay (ipma) for antibodies in tissue extracts and later on confirmed by the direct-ift on cryostat sections, animal inoculation and haemadsorption. clinical signs and post-mortem lesions were consistent with t ...	1986	3518145
two-dimensional analysis of african swine fever virus proteins and proteins induced in infected cells.	two-dimensional (2d) analysis of african swine fever (asf) virus purified by percoll gradient centrifugation resolves 54 structural proteins, 30 in conventional ief gels and 24 in nephge gels, while only 26 structural proteins are separated by sds-page. the two main bands separated by sds-page, with mol wt 150k and 72k, correspond to single spots in 2d gels. other bands, including major bands of 38k, 35k, 24k, 17k, and 15.5k mol wt, correspond to multiple proteins of the same molecular weight bu ...	1986	3521071
in vitro and in vivo association of african swine fever virus with swine erythrocytes.	the association of african swine fever virus (asfv) with swine erythrocytes in vivo, in high titers, was verified by inoculating 30 pigs with 17 asfv isolates and assaying their plasma and washed erythrocyte fractions for residual virus. viral antigens were specifically localized on the surface of in vitro and in vivo swine erythrocytes, using the fluorescent antibody technique and 3 monoclonal antibodies specific for asfv. the same monoclonal antibodies immunoprecipitated virus-specific polypep ...	1986	3521406
identification of african swine fever viral antigens in the hemolymph of soft ticks (argasidae: ornithodoros) by the immunodot blot test.	the immunodot blot test was used to identify african swine fever virus (asfv) antigens in the hemolymph from soft ticks (ornithodoros coriaceus) fed on asfv-infected pigs. the immunodot blot test was sensitive and specific for asfv antigens and has potential field application. hemolymph from field-collected ticks can be screened for asfv and a variety of other tick-borne pathogens using this test.	1986	3532842
an epizootic of african swine fever in belgium and its eradication.	in march 1985 an outbreak of african swine fever was diagnosed in belgium, in the province of west flanders. the source of the infection was probably pork imported from spain which was fed to only one boar. a total of 12 farms were infected in the epizootic out of 185 farms which were in contact. severe control measures were imposed and the pigs on 60 farms were slaughtered (34,041 animals). in september 1985, it was concluded that african swine fever had been eradicated. this conclusion was bas ...	1987	3603981
glycosylated components induced in african swine fever (asf) virus-infected vero cells.	african swine fever (asf) virus production was inhibited more than 100 fold by 5 mm glucosamine, 2 mm 2-deoxyglucose and 3 microm tunicamycin. asf virus induced in vero cells the synthesis of 19 glycosylated components of molecular weights ranging from 9k to 220k, the major ones being those of 9k, 13k, 14k, 74k and 220k. at least five of the induced glycosylated components, of molecular weights 13k, 33k, 34k, 38k and 220k, were probably virus-coded glycoproteins, as suggested by a comparative an ...	1987	3617927
african swine fever. ii. functional disturbances of thrombocytes in pigs infected with virulent haemadsorbing and non-haemadsorbing virus isolates.	increased bleeding time, impaired blood clot retraction and decreased thrombocyte aggregation were observed in pigs infected with virulent haemadsorbing and non-haemadsorbing african swine fever virus isolates. these changes appeared to be more frequent and more severe in pigs infected with the haemadsorbing virus isolates than in those infected with the non-haemadsorbing isolate. moreover, the onset and severity of these changes followed the numerical decrease and morphological damage to these ...	1987	3627730
in vivo and in vitro effects of moderately virulent african swine fever virus on mitogenesis of pig lymphocytes.	six pigs were infected oro-nasally with a moderately virulent african swine fever (asf) virus from the dominican republic (dr ii). the effect of virus infection on the pig's immune system was tested by measuring peripheral leucocyte numbers and the ability of mononuclear leucocytes (mnl) to respond by lymphocyte proliferation (lp) to the mitogens phytohemagglutinin-p (pha-p), concanavalin-a (con-a), and pokeweed mitogen (pwm). all 6 pigs developed high viremias between 4 and 18 days post-inocula ...	1987	3629941
proteins synthesized in african swine fever virus-infected cells analyzed by two-dimensional gel electrophoresis.	at least 74 acidic and 37 basic proteins are synthesized in african swine fever virus (asfv)-infected monkey cells not detected in uninfected cells analyzed by two-dimensional gel electrophoresis. essentially all the proteins synthesized early during infection are also observed at late times. the use of inhibitors such as cycloheximide and phosphonoacetate has led to the identification of 34 immediate early and 13 delayed early polypeptides. therefore 64 proteins were classified as late polypept ...	1987	3629977
in vitro immune serum-mediated protection of pig monocytes against african swine fever virus.	serum samples from pigs that had recovered from infection with a dominican republic isolate of african swine fever virus (asfv) were mixed with dilutions of the virus, then assayed in microcultures of normal pig mononuclear leukocytes to determine whether the samples contained antibodies that protected monocytes against the virus. protection was determined by the difference in titer (log10) between virus mixed with healthy pig serum and virus mixed with immune pig serum, using 50% cytopathogenic ...	1987	3631688
ultrastructure of the liver in pigs with experimental african swine fever.		1987	3672813
synthesis of african swine fever (asf) virus-specific antibodies in vitro in a porcine leucocyte system.	we have developed a system of porcine peripheral blood mononuclear cells for the synthesis of antibodies in vitro, induced by partially purified african swine fever virus particles inactivated with formaldehyde. the antibodies synthesized were detected by a radioimmunoassay with a sensitivity of 3 ng of immunoglobulin. primary responses were dependent on supernatants from peripheral blood mononuclear cells incubated with concanavalin a, macrophages and t lymphocytes. secondary responses did not ...	1987	3679284
dna-binding proteins specified by african swine fever virus.	[35s]methionine-labeled proteins from total or cytoplasmic extracts of vero cells infected with african swine fever virus were chromatographed on native and denatured dna-cellulose and dna-binding proteins were analyzed by sds-polyacrylamide gel electrophoresis (sds-page), by dna binding to western blots, or by two-dimensional electrophoresis. thirteen virus-specific dna-binding proteins were detected by one-dimensional analysis. major species have molecular mass 44,000 (44k), 38k, 20k, 18k, 14k ...	1987	3686826
phosphonylmethoxyalkylpurines and -pyrimidines as inhibitors of african swine fever virus replication in vitro.	several phosphonylmethoxyalkylpurine and -pyrimidine derivatives related to (s)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [(s)-hpmpa] and 9-(2-phosphonylmethoxyethyl)adenine (pmea) were evaluated as inhibitors of african swine fever virus (asfv) replication in vero cells. (s)-hpmpa has previously been shown to inhibit asfv replication at a minimum inhibitory concentration (mic) of 0.01 microgram/ml with a selectivity index of 15000. of the new compounds tested, the following emerged as the ...	1987	3451699
comparative efficacy of broad-spectrum antiviral agents as inhibitors of african swine fever virus replication in vitro.	various nucleoside analogues, selected on the basis of their previously established broad-spectrum antiviral properties, were evaluated for their potency and selectivity as inhibitors of the in vitro replication of the iridovirus, african swine fever virus (asfv). the test compounds included (s)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [(s)-hpmpa], 9-(2-phosphonylmethoxyethyl)adenine, (rs)-3-adenin-9-yl-2-hydroxypropanoic acid isobutyl ester, (s)-9-(2,3-dihydroxypropyl)adenine, carbocyclic ...	1987	3475038
modulation of porcine peripheral blood-derived macrophage functions by in vitro infection with african swine fever virus (asfv) isolates of different virulence.	macrophages play an important role in defense against invading pathogens and neoplastic diseases. their ability to maintain their functional characteristics is also important in the survival of the host. loss of macrophage function during infection may be important in determining resistance or susceptibility of a host species. in this communication, we describe the effect of asfv replication, in macrophages in vitro, on the functional characteristics of these cells. infection with asfv did not a ...	1987	3509675
abortion in sows experimentally infected with african swine fever virus: pathogenesis studies.	thirteen sows that were 38 to 92 days pregnant were experimentally infected with an african swine fever (asf) virus strain of low virulence (dominican republic isolate). seven of 11 sows that were not killed had aborted. the pathogenesis of the abortions was studied, using virus isolation, tissue immunofluoresence, and histopathologic techniques. african swine fever virus was recovered from 179 of 1,329 (13.5%) fetal tissues tested. the 3 fetal tissues most frequently yielding virus were the fet ...	1987	3826864