Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| a conserved african swine fever virus right variable region gene, l11l, is non-essential for growth in vitro and virulence in domestic swine. | the right variable region of the african swine fever virus (asfv) genome is known to contain genes with functions involving virus virulence and host range in swine. a novel open reading frame, orf l11l, which was absent in the non-pathogenic, cell culture-adapted european isolate ba71v, was identified in the pathogenic african isolate malawi lil-20/1. the location of l11l in the right variable region, together with its absence in ba71v, suggested that l11l may have a function in virus virulence ... | 1998 | 9603334 |
| cloning, expression and sequence analysis of the classical swine fever virus nucleocapsid protein. | the dna complementary to the 5'-terminal 1929 nucleotides of classical swine fever virus (csfv; alias hog cholera virus, hcv) lpc vaccine strain rna was cloned and sequenced. the sequence encompasses a 5'-noncoding region (ncr) of 264 nucleotides and an open reading frame (orf) of 1665 nucleotides. the cloned sequence contains genes of four viral proteins, p23, nucleocapsid (core) protein, e0 and part of e1 proteins. alignment of the 5'-terminal 1929 nucleotides of lpc strain with other strains ... | 1998 | 9608668 |
| the recombinant nucleocapsid protein of classical swine fever virus can act as a transcriptional regulator. | the cdna of the nucleocapsid (core) protein of classical swine fever virus (csfv) was generated by reverse transcription-polymerase chain reaction (rt-pcr) and cloned into a eukaryotic expression vector. the effect of the recombinant core protein on the transcriptional regulation of cellular as well as viral promoters was studied. using transient transfection assay, our results demonstrated that the core protein can activate the promoter of human heat shock protein 70 gene, and suppressed the sv ... | 1998 | 9617770 |
| differentiation of types 1a, 1b and 2 bovine viral diarrhoea virus (bvdv) by pcr. | there are two genotypes among bovine viral diarrhoea viruses (bvdv), bvdv1 and bvdv2. within the bvdv1 genotype there are two distinct subgenotypes, bvd1a and bvd1b. serology and monoclonal antibody binding are used to differentiate bvdv from classical swine fever virus (csfv) and border disease virus (bdv), the other members of the pestivirus genus. these techniques are less useful in the differentiation and segregation of viruses within the bvdv species. in this study, differential polymerase ... | 1998 | 9633045 |
| african swine fever: a disease characterized by apoptosis. | the cell tropism, organ distribution and resultant pathology of african swine fever were compared in domestic pigs infected with lethal (malawi) and sublethal (malta) isolates of african swine fever virus (asfv). after infections with both isolates, asfv was predominantly localized in cells of the mononuclear phagocytic system and was not observed in endothelial cells in lymphoid tissue. more severe tissue destruction and cell depletion, associated with high levels of infected macrophages, were ... | 1998 | 9634085 |
| the pathogenesis of african swine fever in the resistant bushpig. | bushpigs and warthogs are natural reservoir hosts of african swine fever virus (asfv) in the wild, showing no clinical signs of disease when infected with the same highly virulent isolates of asfv that induce rapid, haemorrhagic death in domestic pigs. in contrast to domestic pigs, infection of bushpigs with malawi isolate results in low levels of virus replication and lymphocyte apoptosis within the spleen, and a relatively low spread of virus to other lymphoid tissues. however, at 10 days post ... | 1998 | 9634086 |
| development of new cloning vectors for the production of immunogenic outer membrane fusion proteins in escherichia coli. | the pseudomonas aeruginosa lipoprotein gene (opri) was modified by cloning an in-frame polylinker in both orientations at the end of opri. the resulting plasmids pvub1 and pvub2 allow high lipoprotein production in e. coli after iptg induction. the modified lipoproteins are present in the outer membrane and surface-exposed. outer membrane-bound fusion proteins of different sizes were produced and used to generate antibodies without use of adjuvant. an 87 bp dna fragment from the vp72 capsid prot ... | 1996 | 9636324 |
| modulation of t cell and monocyte function in the spleen following infection of pigs with african swine fever virus. | infection of pigs with many strains of african swine fever virus (asfv) has been shown to cause a loss or marked decrease in the ability of splenocytes to respond to mitogens. these observations have been extended by cell fractionation and reconstitution experiments to show that the mitogen stimulated proliferative capacity of both the cd4+ and cd8+ t cells is affected. similarly, monocytes which are directly infectable by virus, are functionally defective as antigen presenting cells when added ... | 1998 | 9646434 |
| entry of african swine fever virus into vero cells and uncoating. | african swine fever virus (asfv) enters vero cells by adsorptive endocytosis [valdeira, m.l., geraldes, a., 1985. morphological study on the entry of african swine fever virus into cells, biol cell. 55, 35-40]. electron microscopy of a lysosomotropic drug-controlled penetration indicated that this step takes place in the endosomes, after fusion between the viral envelope and the limiting membrane of the endosome. inhibition studies with colcemid, cytochalasin b, sodium azide, dinitrophenol, lyso ... | 1998 | 9646445 |
| development and evaluation of a novel antigen capture assay for the detection of classical swine fever virus antigens. | an antigen-capture enzyme immunoassay (eia) was developed to detect classical swine fever virus (csfv) antigen directly from 10% w/v tissue suspension. the assay, based on the sandwich principle, uses a biotinylated monoclonal antibody bound to streptavidin-coated microplates as the capture system and a swine anti-csfv antibody and rabbit anti-swine hrpo-conjugate as the detector system. the antigen-capture eia was compared with conventional virus isolation and polymerase chain reaction (pcr) fo ... | 1998 | 9646447 |
| molecular characterization of the 3' noncoding region of classical swine fever virus vaccine strains. | the genomes of classical swine fever virus (csfv) vaccine strains are poorly characterized, and the mechanisms for their attenuation remain unknown. the aim of the present study was to characterize the 3' noncoding region (3' ncr) of a number of attenuated vaccine strains of csfv in order to examine changes in the viral genome after attenuation. the results showed that the 3' ncr:s of porcivac, rovac, russian lk and original chinese vaccine strain contain insertions very similar to that present ... | 1998 | 9654685 |
| low density blood granulocytic cells induced during classical swine fever are targets for virus infection. | classical swine fever virus infection of pigs causes a severe leukopenia and immunosuppression. in the present study, the kinetics of virus infection, and identification of target cells for the virus in peripheral blood were analysed. virus infection was often not detectable before 5-7 days p.i. a minority of animals yielded detectable infected cells at 3 days p.i., but < 5% pbmc. it was not until 10 days p.i. that this figure increased-to 35-70% pbmc depending on the animal. detailed analysis o ... | 1998 | 9656461 |
| membrane-anchored incorporation of a foreign protein in recombinant influenza virions. | the rna polymerase i system for in vivo synthesis of recombinant influenza vrna molecules was used for the expression of a chimeric protein, consisting of the 341-amino-acid ectodomain of the glycoprotein e2 of classical swine fever virus and the 37-amino-acid c-terminal membrane anchor of the influenza virus hemagglutinin (ha). during infection with an influenza a helper virus the amplified pseudo-viral rna was packaged into progeny virions together with influenza vrna segments. the foreign fus ... | 1998 | 9656996 |
| african swine fever virus infection of the bushpig (potamochoerus porcus) and its significance in the epidemiology of the disease. | warthog (phacochoerus aethiopicus), giant forest hog (hylochoerus meinertzhageni) and bushpig (potamochoerus porcus) are known to be susceptible to infection with african swine fever (asf) virus. little however, is known about the ecology of the disease in the bushpig. this study has shown that the bushpig remains viraemic for between 35 and 91 days following infection during which time it is able to infect the tick vector o. moubata. these ticks were able to transmit the disease to pigs. the vi ... | 1998 | 9659687 |
| [the situation of classical swine fever in wild boars in the european community and selected aspects of disease transmission]. | the situation of classical swine fever (csf) in europe is described on the basis of the literature. in the european community, csf is present among wild boars in germany (federal states mecklenburg-western pomerania, brandenburg and lower saxony), in france (northern vosges) and in italy (regio emìlìa romagna in 1997 and sardinia--enzootically infected). infected wild boars are important as a source of infection for domestic pigs in germany. selected aspects of the transmission of csf virus from ... | 1998 | 9674308 |
| a viral mechanism for inhibition of the cellular phosphatase calcineurin. | the transcription factor nfat (nuclear factor of activated t cells) controls the expression of many immunomodulatory proteins. african swine fever virus inhibits proinflammatory cytokine expression in infected macrophages, and a viral protein a238l was found to display the activity of the immunosuppressive drug cyclosporin a by inhibiting nfat-regulated gene transcription in vivo. this it does by binding the catalytic subunit of calcineurin and inhibiting calcineurin phosphatase activity. | 1998 | 9677199 |
| full-length gbv-c/hgv genomes from nine japanese isolates: characterization by comparative analyses. | the genomes of nine gbv-c/hgv isolates from japanese chronic hepatitis patients were fully sequenced and characterized. they shared 85% nucleotide sequence homology with previously characterized isolates from the us and west africa. homology studies and phylogenetic analyses showed that the japanese isolates formed a third group distinct from the established groups 1 and 2. the genetic distances between the three groups of gbv-c/hgv were very similar to the distances between the two classical sw ... | 1998 | 9687865 |
| border disease of sheep and goats. | border disease (bd) is a congenital virus disease of sheep and goats first reported in 1959 from the border region of england and wales. bd virus (bdv) is a pestivirus in the genus flaviviridae and is closely related to classical swine fever virus and bovine virus diarrhoea virus (bvdv). nearly all isolates of bdv are non-cytopathogenic (ncp) in cell culture. there are no defined serotypes but pestiviruses isolated from sheep exhibit considerable antigenic diversity and three distinct antigenic ... | 1998 | 9689745 |
| ultrastructural pathology of the bone marrow in pigs inoculated with a moderately virulent strain (dr'78) of african swine fever virus. | interpretation of changes in bone marrow during infectious processes is quite complex. this paper reports bone marrow lesions observed in pigs inoculated with a moderately virulent asf virus strain and studies their relationship to the pathogenesis of the disease. in this work, we have carried out the structural and ultrastructural study of the bone marrow of 14 large white x landrace pigs that were inoculated by the intramuscular route with 10(5) 50% hemodsorbing doses (had50) of the dominican ... | 1998 | 9690128 |
| macrophage culture: influence of species-specific incubation temperature. | cultured mammalian cells are traditionally maintained at 37 degrees c, despite the fact that core body temperatures differ considerably among mammals. considering the body temperature of the adult pig, comparison was made of porcine macrophage cultures maintained at 37 degrees c and 39.2 degrees c. examination of the cells showed that granularity was higher in macrophages maintained at 39.2 degrees c, although no differences in cell size were observed. the density of mhc class i and ii expressio ... | 1998 | 9692868 |
| a novel approach to the detection of classical swine fever virus by rt-pcr with a fluorogenic probe (taqman). | detection of classical swine fever virus (csfv) and its discrimination from other pestiviruses can be achieved by virus isolation (vi) in cell cultures, antigen detection, or molecular analysis. to simplify the latter, a 5'-nuclease assay (taqman) was developed for the rapid and specific detection of csfv with the minimum of downstream pcr processing. a pair of 5'-non-coding region, panpestivirus-specific pcr primers were assessed in a one-step reverse transcription-pcr with each of 36 diverse p ... | 1998 | 9694320 |
| detection of african swine fever virus in infected pig tissues by immunocytochemistry and in sity hybridisation. | the techniques for determining cellular sites of establishment and persistence of african swine fever virus (asfv) were established in susceptible domestic pigs and the resistant african reservoir hosts, the warthog and bushpig. detection, both in vitro and in vivo, was achieved by in situ hybridisation and immunocytochemistry, focusing principally on specific probes for vp73, a major capsid protein. hybridisation of radio-labelled probes for dna and rna was relatively insensitive and time consu ... | 1998 | 9694328 |
| migration of mitochondria to viral assembly sites in african swine fever virus-infected cells. | an examination by electron microscopy of the viral assembly sites in vero cells infected with african swine fever virus showed the presence of large clusters of mitochondria located in their proximity. these clusters surround viral factories that contain assembling particles but not factories where only precursor membranes are seen. immunofluorescence microscopy revealed that these accumulations of mitochondria are originated by a massive migration of the organelle to the virus assembly sites. v ... | 1998 | 9696857 |
| classical swine fever virus leader proteinase npro is not required for viral replication in cell culture. | the sequence encoding the viral leader proteinase npro was replaced by the murine ubiquitin gene in a full-length cdna clone of the classical swine fever virus (csfv) strain alfort/187. the recombinant virus va187-ubi showed growth characteristics similar to those of the parent va187-1 virus. at two occasions cells infected with va187-ubi exhibited a cytopathic effect and were found to contain a subgenomic viral rna. this rna lacked the same viral genes as the subgenomic rna which has been found ... | 1998 | 9696875 |
| [procoagulant activity in swine leukocytes, infected with the swine classical plague virus]. | an increased level of the procoagulant activity (pca) has been observed in porcine leukocytes in vitro infected with virulent or vaccine strains of hog cholera virus in comparison with intact cells. pca was similarly induced in infected leukocytes from swine immune to hog cholera virus. increased pca levels were detected in culture medium with leukocytes from intact and immune animals infected in vitro with both virulent and vaccine strains of hog cholera virus in comparison with the pca levels ... | 1998 | 9702815 |
| critical factors affecting the diagnostic reliability of enzyme-linked immunosorbent assay formats. | this paper aims to evaluate different formats of the enzyme-linked immunosorbent assays (elisas) for detection of virus-specific antibodies and focuses on factors that may influence the diagnostic reliability of such tests. newly developed and well-established elisas for detection of infections of bovine herpesvirus 1 (bhv1), bovine respiratory syncytial virus (brsv), classical swine fever virus (csfv), pseudorabies virus (prv) and bovine viral diarrhoea virus (bvdv) are used as examples. differ ... | 1998 | 9713894 |
| cholesterol affects african swine fever virus infection. | african swine fever virus (asfv) enters cells by receptor mediated endocytosis and requires a fusion event between the viral envelope and the limiting membrane of the endosome at low ph. in order to investigate the role of cholesterol in the early stages of asfv infection, we have studied the effect of the removal of cell and viral membrane cholesterol by cholesterol oxidase treatment of cells and virions, as well as the effect of some inhibitors of cholesterol synthesis on the infectious pathwa ... | 1998 | 9714715 |
| isolation and characterization of cytopathogenic classical swine fever virus (csfv). | two new classical swine fever virus (csfv) isolates obtained from naturally infected swine were found to exhibit a cytopathogenic (cp) phenotype. according to their reactivity with monoclonal antibodies (mabs) the isolates cpbw1 and cpmvp1 were classified as antigenic types "lothringen'92" and "flandern'90", respectively. in northern blot analyses and pcr assays csfv rna of subgenomic length was detected in infected cells indicating the presence of defective interfering particles. nucleotide seq ... | 1998 | 9722875 |
| serological and immunohistochemical study of african swine fever in wild boar in spain. | a serological and immunohistochemical study of african swine fever was carried out in wild boar killed in seven municipalities in the north of the province of córdoba during two hunting seasons (1991-92 and 1992-93), when the area was affected by the disease. fourteen of 147 wild boar analysed by elisa and immunoblotting had antibodies to african swine fever virus. the immunohistochemical study revealed that four cases (two seropositive and two seronegative) showed immunoreactivity to the anti-v ... | 1998 | 9725185 |
| intracellular virus dna distribution and the acquisition of the nucleoprotein core during african swine fever virus particle assembly: ultrastructural in situ hybridisation and dnase-gold labelling. | african swine fever virus (asfv) is a large complex icosahedral double-stranded dna virus that replicates in the cytoplasm of susceptible cells. assembly of new virus particles occurs within the perinuclear viroplasm bodies known as virus factories. two types of virus particle are routinely observed: "fulls," which are particles with an electron-dense dna-containing nucleoid, and "empties," which consist of the virus protein and membrane icosahedral shell but are without the incorporation of the ... | 1998 | 9740789 |
| pathogenesis of mucosal disease, a deadly disease of cattle caused by a pestivirus. | two biotypes of pestiviruses, cytopathogenic (cp) and non-cytopathogenic (noncp) viruses, are distinguished by their effects on tissue culture cells. in contrast to the bovine viral diarrhoea virus (bvdv) system, only a few cp border disease virus (bdv) and cp classical swine fever virus (csfv) strains have been described. antigenically closely related noncp and cp bvdv can be isolated from cattle with fatal mucosal disease (md) and are called a virus pair. the generation of cp bvdv in an animal ... | 1998 | 9741637 |
| maternal recognition of foetal infection with bovine virus diarrhoea virus (bvdv)--the bovine pestivirus. | pestiviruses are the veterinary viruses with genome homology to human hepatitis c virus (hcv). this group includes classical swine fever virus (csfv), border disease virus of sheep (bdv) and bovine virus diarrhoea virus (bvdv). there are some similarities in the pathology of all three virus infections; in utero transmission to the foetus can cause early embryonic losses, severe congenital abnormalities and, particularly with bvdv, lifelong persistent infections. in situ hybridisation studies hav ... | 1998 | 9741639 |
| immunohistochemical and ultrastructural evidence of hog cholera virus infection of megakaryocytes in bone marrow and spleen. | twelve pigs were inoculated with a highly virulent strain of hog cholera virus (hcv) to study viral infection of megakaryocytes in the bone marrow and spleen. immunohistochemical and ultrastructural examination revealed hcv infection in a small proportion (2.5-9.0%) of these cells from the 2nd to the 9th day after inoculation, at which time the experiment was terminated. megakaryocyte infection accounts for the presence of viral antigens in platelets. the latter may represent a passive vehicle f ... | 1998 | 9749356 |
| [classical swine fever in 1993 in switzerland: molecular-epidemiologic characterization of the virus isolate]. | rt-pcr followed by direct nucleotide sequencing of the amplified cdna was carried out to analyse most of the 5' nontranslated region (5'ntr) of classical swine fever virus (csfv) isolates from the five 1993 disease outbreaks in switzerland. sequence data were compared to other csfv strains, and dendrograms were constructed in order to determine the phylogenetic relationship of the swiss virus strains. dendrograms formed by the analysis of different parts of the 5'ntr were compared. it was shown ... | 1998 | 9757784 |
| comparative detection of classical swine fever virus in striated muscle from experimentally infected pigs by reverse transcription polymerase chain reaction, cell culture isolation and immunohistochemistry. | classical swine fever (csf) is a highly contagious viral disease, which can be transmitted by csfv-contaminated swill. in 1993, four csf outbreaks in switzerland were caused presumably by feeding pigs with improperly heated swill. the aim of the investigations was to find a suitable method for csfv detection in striated muscle samples of infected pigs in order to allow routine testing of meat for virus contamination. the sensitivity of virus detection in striated muscle was compared with the det ... | 1998 | 9763128 |
| african swine fever virus is enveloped by a two-membraned collapsed cisterna derived from the endoplasmic reticulum. | during the cytoplasmic maturation of african swine fever virus (asfv) within the viral factories, the dna-containing core becomes wrapped by two shells, an inner lipid envelope and an outer icosahedral capsid. we have previously shown that the inner envelope is derived from precursor membrane-like structures on which the capsid layer is progressively assembled. in the present work, we analyzed the origin of these viral membranes and the mechanism of envelopment of asfv. electron microscopy studi ... | 1998 | 9765444 |
| application of genetic methods to study the relationship between classical swine fever outbreaks. | eleven viruses isolated between 1993 and 1997 from outbreaks of classical swine fever in the neighbouring countries of slovakia, the czech republic and austria were compared after partial sequencing of the ns5b and e2 genes. viruses collected from south-central and west slovakia were indistinguishable during a period of four years, even when associated with outbreaks of variable severity. outbreaks that occurred in the czech republic in 1996 involved two types of virus, one of which was related ... | 1998 | 9769081 |
| an rt-pcr assay for the specific detection of classical swine fever virus in clinical samples. | a simple reverse transcriptase-polymerase chain reaction (rt-pcr) assay has been developed for the specific amplification of dna after reverse transcription of rna from the classical swine fever virus (csfv). a pair of oligonucleotides was selected from an area of high homology in the genome of csfv strains, but which differed from the corresponding sequences in the genome of bovine viral diarrhea virus (bvdv) strains. using these primers (csfv1-csfv2), a csfv specific dna band of 174 bp was amp ... | 1998 | 9779556 |
| african swine fever virus nl gene is not required for virus virulence. | previously, we described a highly conserved nonessential african swine fever virus (asfv) right variable region gene, nl. deletion of nl from the european pathogenic isolate e70 resulted in almost complete attenuation of the virus in domestic swine. to study gene function further, nl gene deletion mutants were constructed from two pathogenic african asfv isolates, malawi lil-20/1 (mal) and pretoriuskop/96/4 (pr4). unexpectedly, both mal (mal-deltanl) and pr4 (pr4deltanl) null mutants remained hi ... | 1998 | 9780062 |
| classical swine fever virus: discrimination between vaccine strains and european field viruses by restriction endonuclease cleavage of pcr amplicons. | 1998 | 9787502 | |
| [methods of laboratory diagnosis of hog cholera]. | the review emphasizes the significance of laboratory methods for the diagnosis of hog cholera virus. in addition to virus isolation and immunofluorescent method, enzyme immunoassay (eia) of virus-specific antigen and antibodies are recommended. commercial eia kits for laboratory diagnosis of hog cholera virus and test-systems whose development is in progress now are characterized. | 1998 | 9791879 |
| functionality and cell anchorage dependence of the african swine fever virus gene a179l, a viral bcl-2 homolog, in insect cells. | the african swine fever virus gene a179l has been shown to be a functional member of the ced9/bcl-2 family of apoptosis inhibitors in mammalian cell lines. in this work we have expressed the a179l gene product (p21) under the control of the baculovirus polyhedrin promoter using a baculovirus system. expression of the a179l gene neither altered the baculovirus replication phenotype nor delayed the shutoff of cellular protein synthesis, but it extended the survival of the infected insect cells to ... | 1998 | 9811766 |
| the african swine fever virus thymidine kinase gene is required for efficient replication in swine macrophages and for virulence in swine. | african swine fever virus (asfv) replicates in the cytoplasm of infected cells and contains genes encoding a number of enzymes needed for dna synthesis, including a thymidine kinase (tk) gene. recombinant tk gene deletion viruses were produced by using two highly pathogenic isolates of asfv through homologous recombination with an asfv p72 promoter-beta-glucuronidase indicator cassette (p72gus) flanked by asfv sequences targeting the tk region. attempts to isolate double-crossover tk gene deleti ... | 1998 | 9811782 |
| establishment of a serum-free culture cell line, cpk-ns, which is useful for assays of classical swine fever virus. | a stable porcine kidney cell line, cpk-ns, was established and maintained in serum-free culture. a cytopathic effect (cpe) was observed clearly in cpk-ns cells infected with some classical swine fever virus (csfv) strains which did not show the exaltation of newcastle disease virus (end) phenomenon. chromosome condensation and dna fragmentation, a marker for apoptosis, were detected in cells infected with end phenomenon-negative csfv strains. by using the cpe induced by infection with an end phe ... | 1998 | 9820575 |
| identification of a 25-aminoacid sequence from the major african swine fever virus structural protein vp72 recognised by porcine cytotoxic t lymphocytes using a lipoprotein based expression system. | identification of african swine fever virus (asfv) proteins recognised by cytotoxic t lymphocytes (ctl) from swine surviving asfv/nh/p68 infection was assessed using expression vectors based on the pseudomonas aeruginosa outer membrane lipoprotein i gene (opri). viral antigens expressed as fusion lipoproteins were shown to be taken efficiently by porcine blood-derived macrophages incubated with outer membrane protein preparations from transformed e. coli. to assess recognition by ctl the fusion ... | 1998 | 9820580 |
| in vivo effect on pig chromosomes of high dosage vaccine against classic swine fever. | hog cholera virus (hcv) can induce chromosome abnormalities in diseased pigs as well as in those vaccinated with attenuated virus vaccine against classic swine fever. an experiment was made using animals from potency and safety control tests of commercial vaccines in argentina. the different types of chromosomal alterations observed were chromatid and chromosome breaks, chromatid exchanges, polyploid, multiple aberrations cells, and chromosome pulverization. in this study the occurrence of chrom ... | 1998 | 9838191 |
| comparison of a reverse transcription-polymerase chain reaction assay and virus isolation for the detection of classical swine fever virus. | the authors evaluated the ability of a reverse transcription-polymerase chain reaction (rt-pcr) assay to detect classical swine fever virus (csfv) in comparison with virus isolation and detection by an indirect immunoperoxidase assay (vi-ipa). to determine the specificity of the assay, samples from 60 spleens, 45 tonsils, ten submandibular lymph nodes, eight mesenteric lymph nodes and four kidneys, collected from pigs of various ages which had been slaughtered in abattoirs in canada (a populatio ... | 1998 | 9850538 |
| application of a computer program for genetic typing of classical swine fever virus isolates from germany. | the commercial software program hla sequityper (amersham pharmacia biotech), designed originally for human leukocyte antigen typing, was adapted for rapid typing of classical swine fever (csf) virus isolates. the program compares new sequence data with those stored in a database file and calculates the most probable assignment. for generating the csf virus sequence database, 150 bp of the 5' nontranslated genomic region (5'-ntr) from 88 german classical swine fever virus isolates from outbreaks ... | 1998 | 9870589 |
| porcine cells persistently infected with classical swine fever virus protected from pestivirus-induced cytopathic effect. | cytopathogenicity of classical swine fever virus (csfv) depends on the presence of defective particles containing a subgenomic (sg) rna with a defined deletion. in a previous report we described the spontaneous generation of this sg rna and therefore of cytopathogenic (cp) csfv in porcine kidney cell cultures persistently infected with csfv. frequently, some cells survived the cpe and could be further propagated. they remained positive for viral antigen and continued to shed complete virus and i ... | 1998 | 9880012 |
| characterization of immobilization methods for african swine fever virus protein and antibodies with a piezoelectric immunosensor. | a direct piezoelectric flow injection analysis immunoassay for the detection of african swine fever virus and antibodies is presented. the peptide-specific monoclonal antibody 18bg3 and the virus protein 73 were used for detection with a quartz crystal microbalance. accumulation of the analyte on the surface of this mass-sensitive biosensor resulted in a shift of the resonant frequency. highly selective receptor layers were applied on the sensing electrode of the quartz crystal for detection of ... | 1998 | 9883562 |
| prostaglandin a1 inhibits replication of classical swine fever virus. | prostaglandins (pgs) have been shown to inhibit the replication of several dna and rna viruses. here we report the effect of prostaglandin (pga1) on the multiplication of a positive strand rna virus, classical swine fever virus (csfv) in pk15 cells. pga1 was found to inhibit the multiplication of csfv. at a concentration of 5 micrograms/ml, which was nontoxic to the cells, pga1 inhibitis virus production in 99%. in pga1 treated cells the size and number of characteristic classical swine fever fo ... | 1998 | 9921308 |
| molecular cloning and nucleotide sequence of 3'-terminal region of classical swine fever virus lpc vaccine strain. | a cdna of the 3'-terminus of classical swine fever virus (lpc vaccine strain) was cloned and sequenced. the 3431 nucleotides and deduced amino acid sequences were compared with those of other pestiviruses, and the similarity of nucleotide sequences and deduced amino acid sequences were found to be 84-95% and 95-98%, respectively. similar to other isolates of classical swine fever virus, the sequenced region included the non-structural gene p58 (ns5a) and part of p76 (ns5b) gene. the p76 gene of ... | 1998 | 9926397 |
| african swine fever virus infection induces tumor necrosis factor alpha production: implications in pathogenesis. | we have analyzed the production of tumor necrosis factor alpha (tnf-alpha) induced by in vitro infection with african swine fever (asf) virus (asfv) and the systemic and local release of this inflammatory cytokine upon in vivo infection. an early increase in tnf-alpha mrna expression was detected in asfv-infected alveolar macrophages, and high levels of tnf-alpha protein were detected by elisa in culture supernatants from these cells. when animals were experimentally infected with a virulent iso ... | 1999 | 9971800 |
| a lipid modified ubiquitin is packaged into particles of several enveloped viruses. | an anti-ubiquitin cross-reactive protein which migrates more slowly (6.5 kda) by sds-page than ubiquitin was identified in african swine fever virus particles. this protein was extracted into the detergent phase in triton x-114 phase separations, showing that it is hydrophobic, and was radiolabelled with both [3h]palmitic acid and [32p]orthophosphate. this indicates that the protein has a similar structure to the membrane associated phosphatidyl ubiquitin described in baculovirus particles. a si ... | 1999 | 10037162 |
| oral immunisation of swine with a classical swine fever vaccine (chinese strain) and transmission studies in rabbits and sheep. | seven experiments including a total of 47 pigs, 11 wild boars, 26 rabbits, 10 hares and 16 sheep were carried out to assess the efficacy, safety and transmission of the chinese vaccine strain of the classical swine fever virus (csfv) administrated by the oral route. within 3 weeks after oral vaccination, a clear seroconversion occurred in the pigs. six weeks after vaccination, vaccinated pigs were fully protected against a virulent challenge. the c-strain was not isolated from tonsils, spleen, l ... | 1999 | 10063532 |
| genetic heterogeneity of porcine and ruminant pestiviruses mainly isolated in japan. | the genetic variability of porcine and ruminant pestiviruses was studied by comparative nucleotide sequence analysis of 73 isolates (42 porcine and 31 ruminant), including 65 japanese isolates (35 porcine and 30 ruminant). the 5'-untranslated region (utr) amplified by reverse transcriptase-polymerase chain reaction (rt-pcr) was determined by direct sequencing and phylogenetic analysis was performed from the nucleotide sequence data. most porcine isolates were divided into two major subgroups, cl ... | 1999 | 10068129 |
| an experimental marker vaccine and accompanying serological diagnostic test both based on envelope glycoprotein e2 of classical swine fever virus (csfv). | envelope glycoprotein e2 is the most immunogenic protein of classical swine fever virus (csfv). in a proposed model of the antigenic structure of e2, the n-terminal half of e2 forms two independent structural antigenic units, a and bc. e2 without transmembrane region (e2-tmr) is expressed and secreted into the medium of insect cells by use of the baculovirus expression system. the immune response induced by e2 protects pigs against csfv. recently, we showed that the protective immune response to ... | 1999 | 10073720 |
| incidence of classical swine fever (csf) in wild boar in a densely populated area indicating csf virus persistence as a mechanism for virus perpetuation. | a virological survey was carried out to establish the distribution of classical swine fever (csf) virus among wild boar in the federal state of brandenburg, germany. organ materials and blood samples were collected from 11,670 wild boar shot or found dead during the period march 1995 to december 1997. in total 211 (1.8%) wild boar were positive for csf virus or antigen. the incidence of csf-positive animals decreased continuously from 4.6% at the beginning of the epidemic in 1995 to 0.7% in 1997 ... | 1999 | 10085775 |
| nuclear and nucleolar localization of an african swine fever virus protein, i14l, that is similar to the herpes simplex virus-encoded virulence factor icp34.5. | pcr analysis of the genomes of 18 different african swine fever virus (asfv) isolates showed that the i14l open reading frame (orf) was present as either a long form or short form in all of the isolates. sequencing of the orf from eight isolates confirmed that both forms of the orf were well conserved. antisera raised against the i14l protein identified the long form of the protein as a 21 kda protein expressed late during asfv infection. immunofluorescent analysis of transiently expressed haema ... | 1999 | 10091989 |
| [comparison of laboratory diagnostic methods for the detection of infection with the virus of classical swine fever in the early inspection phase: an experimental study]. | virus isolation in the pk-15 cell culture, two commercial antigen elisas, reverse transcriptional-polymerase chain reaction (rt-pcr), and flow cytometry have been evaluated to detect viremic pigs in the early period of classical swine fever virus (csfv) infection. domestic pigs were experimentally inoculated with the virulent csfv strain 'alfort 187' and two field isolates. csfv isolation and rt-pcr were found to be the most sensitive methods for the detection of highly virulent csfv in the earl ... | 1999 | 10189722 |
| [detection of the hog cholera virus using the polymerase chain reaction]. | a rapid and highly sensitive method for detecting hog cholera virus (hcv) based on a reverse transcription of the polymerase chain reaction (rt-pcr) is developed. primers complementary to the most homologous sites of virus genome in an area coding the precursor for glycoproteins gp44/gp48 are selected. detection of the virus in pathological material by the rt-pcr showed that use of these primers in amplification allows detection of different hcv strains. | 1999 | 10190108 |
| selective stimulation of hepatitis c virus and pestivirus ns5b rna polymerase activity by gtp. | ns5b of the hepatitis c virus is an rna template-dependent rna polymerase and therefore the key player of the viral replicase complex. using a highly purified enzyme expressed with recombinant baculoviruses in insect cells, we demonstrate a stimulation of rna synthesis up to 2 orders of magnitude by high concentrations of gtp but not with atp, ctp, utp, gdp, or gmp. enhancement of rna synthesis was found with various heteropolymeric rna templates, with poly(c)-oligo(g)12 but not with poly(a)-oli ... | 1999 | 10196156 |
| recovery of infectious classical swine fever virus (csfv) from full-length genomic cdna clones by a swine kidney cell line expressing bacteriophage t7 rna polymerase. | a new method for the recovery of infectious classical swine fever virus (csfv) from full-length genomic cdna clones of the c-strain was developed. classical reverse genetics is based on transfection of in vitro transcribed rna to target cells to recover rna viruses. however, the specific infectivity of such in vitro transcribed rna in swine kidney cells is usually low. to improve reverse genetics for csfv, a stable swine kidney cell line was established that expresses cytoplasmic bacteriophage t ... | 1999 | 10204702 |
| efficacy and stability of a subunit vaccine based on glycoprotein e2 of classical swine fever virus. | the purpose of this study was to determine the efficacy and stability of an e2 subunit vaccine against classical swine fever virus (csfv). the vaccine, which contains e2 produced in insect cells by a baculovirus expression vector is a potential marker vaccine, as it allows discrimination between infected and vaccinated pigs. several vaccination-challenge experiments were performed to determine the dose that protects 95% of the vaccinated pigs (pd95), and to determine the stability and efficacy o ... | 1999 | 10227472 |
| [classical swine fever in wild boars in switzerland]. | in may 1998, wild boars with classical swine fever (csf) symptoms were detected in the southern part (canton ticino) of switzerland. csf virus was isolated from the submitted samples and rt-pcr followed by direct nucleotide sequencing of the 5' non-translated region showed that this virus was identical to the isolate previously recognized in wild boars from the area of varese (italy). in most animals, antibodies to csf virus were detected as well. an immediate measurement was taken by limiting t ... | 1999 | 10228397 |
| the biological effects induced in mice by p36, a proteinaceous factor of virulence produced by african swine fever virus, are mediated by interleukin-4 and also to a lesser extent by interleukin-10. | we have previously presented indirect evidence that both specific immunosuppression and lymphocyte mitogenicity induced in mice by p36, a proteinaceous factor of virulence produced by porcine monocytes infected by african swine fever virus, were consistent with a th2-driven response. here we show: (1) interleukin-4 (il-4) and interleukin-10 (il-10) mrna expression in the spleen and thymus of c57bl/6 mice were displayed early after p36 inoculation. the expression of thymic il-10 mrna occurred, ho ... | 1999 | 10233720 |
| ns5a, a nonstructural protein of hepatitis c virus, binds growth factor receptor-bound protein 2 adaptor protein in a src homology 3 domain/ligand-dependent manner and perturbs mitogenic signaling. | although hepatitis c virus (hcv) infection is an emerging global epidemic causing severe liver disorders, the molecular mechanisms of hcv pathogenesis remain elusive. the ns5a nonstructural protein of hcv contains several proline-rich sequences consistent with src homology (sh) 3-binding sites found in cellular signaling molecules. here, we demonstrate that ns5a specifically bound to growth factor receptor-bound protein 2 (grb2) adaptor protein. immunoblot analysis of anti-grb2 immune complexes ... | 1999 | 10318918 |
| closed one-tube reverse transcription nested polymerase chain reaction for the detection of pestiviral rna with fluorescent probes. | an assay was developed in which reverse transcription (rt), nested polymerase chain reaction (pcr) and accumulation of amplicon-specific fluorescence could take place in a single, closed reaction tube. the assay, which was classical swine fever virus rna-specific, was compared with other methods for detection of this virus, including various rt-pcr configurations, virus isolation and elisa. the new method was very sensitive, and less prone to giving false positive results compared to nested pcr ... | 1999 | 10328538 |
| replication of african swine fever virus dna in infected cells. | we have examined the ultrastructural localization of african swine fever virus dna in thin-sections of infected cells by in situ hybridization and autoradiography. virus-specific dna sequences were found in the nucleus of infected vero cells at early times in the synthesis of the viral dna, forming dense foci localized in proximity to the nuclear membrane. at later times, the viral dna was found exclusively in the cytoplasm. electron microscopic autoradiography of african swine fever virus-infec ... | 1999 | 10329562 |
| localization of pestiviral envelope proteins e(rns) and e2 at the cell surface and on isolated particles. | the glycoproteins e(rns) of classical swine fever virus (csfv) and e(rns) and e2 of bovine viral diarrhoea virus (bvdv) are shown to be located at the surface of infected cells by the use of indirect immunofluorescence and by cytofluorometric analysis. the positive immunostaining of the cell surface was further analysed by immunogold electron microscopy and it could be shown that only extracellular virions were labelled. gold granules were not seen at the cellular plasma membrane. in contrast to ... | 1999 | 10355762 |
| [use of monoclonal antibodies for studying the classical hog cholera virus]. | numerous monoclonal antibodies (mab) to hog cholera virus are a highly specific and effective instrument for studies of this agent. panels of mab for differential diagnosis of pestiviruses are characterized. international reference panel of 30 mabs is a result of cooperation of european scientists; it was approved as the official reference for assessing all available and new diagnostic agents. mab permit intraspecies differentiation between hog cholera virus strains and, which is particularly im ... | 1999 | 10358897 |
| the african swine fever virus prenyltransferase is an integral membrane trans-geranylgeranyl-diphosphate synthase. | in a previous study, it was shown that the protein encoded by the gene b318l of african swine fever virus (asfv) is a trans-prenyltransferase that catalyzes in vitro the condensation of farnesyl diphosphate and isopentenyl diphosphate to synthesize geranylgeranyl diphosphate and longer chain prenyl diphosphates (alejo, a., yáñez, r. j., rodríguez, j. m., viñuela, e., and salas, m. l. (1997) j. biol. chem. 272, 9417-9423). to investigate the in vivo function of the viral enzyme, we have determine ... | 1999 | 10364254 |
| african swine fever virus: a b cell-mitogenic virus in vivo and in vitro. | the two major characteristics of pathogenesis in african swine fever virus (asfv) infections of domestic pigs are massive b-cell apoptosis and haemorrhage. the effects of asfv on porcine b cells have therefore been systematically examined in vivo, by using virus-infected pigs and scid-beige mice reconstituted with porcine bone marrow, and in vitro, by using porcine b-cell lines and b cells from normal and asfv-infected pigs. secretion of porcine ig was stimulated by asfv both in vivo and in bone ... | 1999 | 10374963 |
| mutations in the ns5a gene predict response to interferon therapy in japanese patients with chronic hepatitis c and cirrhosis. | the virus genotype, serum hcv-rna level and liver histology are reported to be important factors in the response to interferon therapy. recent studies have revealed that hcv ns5a 2209-2248 amino acid changes affect the response to interferon therapy of genotype 1b chronic hepatitis c. in contrast, some studies done in western countries have reported no such correlation. in the present study, interferon therapy was given to 58 japanese patients, including 15 liver cirrhosis patients. ns5a 2209-22 ... | 1999 | 10381214 |
| comparative sequence analysis of classical swine fever virus isolates from the epizootic in the netherlands in 1997-1998. | sixteen classical swine fever virus (csfv) field isolates from outbreaks of classical swine fever from the period between february 1997 and march 1998 in the netherlands were sequence analysed. parts of the 5' noncoding region (5'ncr) and the e1/e2 gene were sequenced after rt-pcr. the obtained sequences were compared with isolates of recent outbreaks in europe and those of former outbreaks in the netherlands. sequence alignment of the 5'ncr region (321 bp) revealed that the isolates of the dutc ... | 1999 | 10384890 |
| genetic variation in the 5' end and ns5b regions of classical swine fever virus genome among japanese isolates. | sixteen clinical strains of classical swine fever virus (csfv) isolated in japan were subjected to analyses of nucleotide sequence variations in the 5' end and ns5b regions of the genome. these isolates were divided into three genovars, csfv-1, csfv-2 and csfv-3, based on palindromic nucleotide substitutions at the three variable loci in the 5' untranslated region (utr). phylogenetic trees constructed from nucleotide sequences in the 5'-utr and ns5b gene indicated that the csfv strains were divi ... | 1999 | 10385204 |
| virus antigen expression and alterations in peripheral blood mononuclear cell subpopulations after classical swine fever virus infection. | depletion in the number of lymphocytes and viral persistence are thought to be the most important outcomes of classical swine fever virus (csfv) infection. to define the change in peripheral blood mononuclear cells (pbmc) and virus replication in leukocytes after csfv infection, 8-week old pigs were infected with the lpc vaccine strain or virulent csfv (hcv-yl strain). changes in the relative number of pbmcs were analyzed by flow cytometry. the results showed a significant increase in the relati ... | 1999 | 10392774 |
| [genetic characteristics of the kc vaccine strain of hog cholera virus: comparative analysis of the primary sequence of surface glycoprotein e(rns), e1, and e2 genes]. | primary structure of a genome fragment of attenuated strain cs of hog cholera virus (hcv) coding for three surface glycoproteins erns, e1, and e2 (fragment size 2379 nucleotides) is analyzed. by the nucleotide sequence the homology between strain cs and ten other virulent and attenuated hcv strains in this area is 84.9-94.6%, 87.2-94.6% in gene erns, 84.6-96.9% in gene e1, and 83.3-94.3% in gene e2. by amino acid sequence the homology is 90.9-94.3%, 92.9-95.0%, 92.3-95.6%, and 88.9-94.1%, respec ... | 1999 | 10396731 |
| genetic analysis of pestiviruses at the 3' end of the genome. | specific pcr primers were selected for each pestivirus genotype which flanked the 3'-part of the ns5b gene and more than three quarters of the 3'-utr. pcr products were sequenced in both directions using an automatic sequencing device and analyzed by computer package program dnastar. a comparative analysis of the 3' untranslated region (3'-utr) of 82 viruses, representing the four genotypes of the pestivirus genus, provided a similar phylogenetic grouping as other genomic regions. intertypic rec ... | 1999 | 10403696 |
| prevalence of gbv-c/hepatitis g virus rna and e2 antibody among subjects infected with human immunodeficiency virus type 1 after parenteral or sexual exposure. | gb virus c (gbv-c) or hepatitis g virus (hgv) is transmitted by the parenteral route but the importance of sexual transmission needs to be ascertained. gbv-c/hgv infections were investigated using rna and e2-antibody detection methods in 80 subjects infected by the human immunodeficiency virus type 1 (hiv-1) divided into 4 groups of 20 individuals each according to their main risk factor for hiv-1 infection: blood product recipients (group 1), intravenous drug users (group 2), homosexuals (group ... | 1999 | 10421404 |
| phenotypic analysis of peripheral leukocytes in piglets infected with classical swine fever virus. | the phenotypic changes in circulating leukocytes in swine fever influenced by classical swine fever virus (csfv) infection with different strain virulence was studied in piglets. the phenotypic differences were measured by monoclonal antibodies specific for porcine differentiation antigens. the pattern of phenotypic change varied with the virulence of csfv. infection with virulent, but not the attenuated strain of csfv resulted in the dramatic early loss of cd8-bearing t lymphocytes from the cir ... | 1999 | 10425241 |
| laboratory-scale inactivation of african swine fever virus and swine vesicular disease virus in pig slurry. | two methods were evaluated for the inactivation of african swine fever (asv) and swine vesicular disease (svd) viruses in pig slurry: chemical treatment and heat treatment. the addition of naoh or ca(oh)2 at different concentration/time combinations at 4 degrees c and 22 degrees c was examined, as was virus stability at different temperature/time combinations. asf virus (asfv) was less resistant to both methods than svd virus (svdv). in slurry from one source, asfv was inactivated at 65 degrees ... | 1999 | 10432596 |
| cytopathogenic and noncytopathogenic rna replicons of classical swine fever virus. | to determine the minimal requirements for autonomous rna replication of classical swine fever virus (csfv), genomes having in-frame deletions within the genes for structural and flanking nonstructural proteins were constructed, based on an infectious cdna clone of csfv alfort/187. rna was transcribed in vitro from the respective plasmids and transfected into sk-6 swine kidney cells. the replication competence of the rna was determined by immunostaining transfected cells for csfv ns3 protein and ... | 1999 | 10438869 |
| classical swine fever in sardinia: epidemiology of recent outbreaks. | a variable region of the gene encoding the major glycoprotein (e2) of classical swine fever virus (csfv) was sequenced from 12 sardinian isolates which had been obtained from three geographically distinct regions of the island. phylogenetic analysis of these viruses and others characterized in previous studies [1, 2] indicated that (a) the sardinian viruses were all members of the common european subgroup 2.3 and were clearly distinct from live vaccines recently used in this area; (b) they could ... | 1999 | 10459661 |
| transmission of classical swine fever virus by artificial insemination. | classical swine fever (csf) virus was introduced into an artificial insemination centre during the csf epizootic of 1997-1998 in the netherlands. the risk of further spread of csf virus via contaminated semen was recognised, but could not be assessed because scientific data on this issue were not available. an animal experiment was performed to determine whether csf virus could be transmitted via artificial insemination with contaminated semen. three boars were inoculated with a csf virus field ... | 1999 | 10466500 |
| design and construction of african swine fever virus chimeras incorporating foreign viral epitopes. | in the present work we have studied the feasibility of introducing foreign epitopes into the african swine fever virus (asfv) particle by genetic manipulation of the virus. for this purpose, we developed specific transfer vectors containing the gene encoding for the highly antigenic structural asfv protein p54 in which foreign sequences were introduced. dna sequences encoding continuous linear epitopes, the antigenic site a from foot-and-mouth disease virus (fmdv) vp1 protein and the da3 antigen ... | 1999 | 10481737 |
| virus-specific cell receptors are necessary, but not sufficient, to confer cell susceptibility to african swine fever virus. | the entry of african swine fever (asf) virus into vero cells and swine macrophages is mediated by saturable binding sites located in the plasma membrane, which have been related, as in other virus-cell systems, to the sensitivity of the cell to the virus. in order to define this correlation, we have analyzed up to 16 cell lines derived from different species for their sensitivity to virus infection, to determine the step in the virus infective cycle that was blocked in each resistant cell, the p ... | 1999 | 10481739 |
| african swine fever virus replication in the midgut epithelium is required for infection of ornithodoros ticks. | although the malawi lil20/1 (mal) strain of african swine fever virus (asfv) was isolated from ornithodoros sp. ticks, our attempts to experimentally infect ticks by feeding them this strain failed. ten different collections of ornithodorus porcinus porcinus ticks and one collection of o. porcinus domesticus ticks were orally exposed to a high titer of mal. at 3 weeks postinoculation (p.i.), <25% of the ticks contained detectable virus, with viral titers of <4 log(10) 50% hemadsorbing doses/ml. ... | 1999 | 10482612 |
| immunohistochemical detection of hog cholera virus antigen in paraffin wax-embedded tissues from naturally infected pigs. | in 17 pigs submitted for diagnosis in 1980, hog cholera was confirmed by viral isolation, by a direct immunofluorescent antibody test for viral antigen, and by the presence of characteristic histopathological lesions. in the present study, hog cholera viral antigen was demonstrated in these pigs by immunohistochemical examination of formalin-fixed paraffin wax-embedded tissues that had been stored for 18 years. viral antigen was detected in crypt epithelial cells of the tonsil, collecting tubula ... | 1999 | 10486165 |
| diva vaccines that reduce virus transmission. | this brief review deals with the effect of diva (differentiating infected from vaccinated individuals) vaccines (also termed marker vaccines) on transmission of herpesviruses and pestiviruses in swine and cattle. pseudorabies and bovine herpesvirus 1 diva vaccines have been demonstrated to reduce transmission of wild-type virus in populations of pigs and cattle in the laboratory as well as in the field. a subunit diva vaccine based on the immunodominant e2 protein of classical swine fever virus ... | 1999 | 10486928 |
| genetic diversity of pestiviruses: identification of novel groups and implications for classification. | the complete npro coding sequences were determined for 16 pestiviruses isolated from cattle, pig, and several wild ruminant species including reindeer, bison, deer, and bongo. phylogenetic analysis enabled the segregation of pestiviruses into the established species bovine viral diarrhea virus-1 (bvdv-1), bvdv-2, border disease virus (bdv), and classical swine fever virus (csfv). for bvdv-1 five distinct subgroups were identified, while bvdv-2, bdv, and csfv were each subdivided into two subgrou ... | 1999 | 10489341 |
| molecular epidemiology of classical swine fever in cuba. | the origin and evolution of the classical swine fever (csf) epizootic that occurred in cuba from 1993 to 1997 has been investigated by the analysis of e2 gene sequences from 15 representative viral isolates as well as the vaccine and the challenge strains used in this country. in the phylogenetic tree derived from these sequences, the cuban isolates were located in a defined cluster within the previously reported genomic subgroup 1.2. this cluster was related, although distinguishable, from the ... | 1999 | 10500283 |
| experimental infection of slaughter pigs with classical swine fever virus: transmission of the virus, course of the disease and antibody response. | the spread of classical swine fever virus was investigated in an isolation unit containing four pens, each containing six slaughter pigs. one pig in the middle pen of three adjacent pens was inoculated intramuscularly and intranasally with the virus. the fourth pen was located in a separate compartment. the pens were visited in a strict order to study, first, the effect of indirect contact via contaminated clothing and footwear on the spread of the virus to adjacent pens and, secondly, the airbo ... | 1999 | 10504066 |
| african swine fever virus dutpase is a highly specific enzyme required for efficient replication in swine macrophages. | the african swine fever virus (asfv) gene e165r, which is homologous to dutpases, has been characterized. a multiple alignment of dutpases showed the conservation in asfv dutpase of the motifs that define this protein family. a biochemical analysis of the purified recombinant enzyme showed that the virus dutpase is a trimeric, highly specific enzyme that requires a divalent cation for activity. the enzyme is most probably complexed with mg(2+), the preferred cation, and has an apparent k(m) for ... | 1999 | 10515998 |
| does porcine reproductive and respiratory syndrome virus potentiate classical swine fever virus infection in weaner pigs? | fifteen 6-week-old crossbred weaners weighing about 12 kg each were randomly divided into three groups of five animals each. one group of pigs was inoculated first with porcine reproductive and respiratory syndrome (prrs) virus and then 3 days later with csf virus. the second group received classical swine fever (csf) virus, while the third group was inoculated with prrs virus only. the aim of the experiment was to determine whether a primary prrs virus infection influences the clinical outcome ... | 1999 | 10528545 |
| intermediate stages in monocyte-macrophage differentiation modulate phenotype and susceptibility to virus infection. | the kinetics of monocyte-macrophage differentiation was analysed using two swine workshop cluster (swc) cd molecules: swc1 and swc9. myeloid cells were selected by labelling for the common myeloid antigen, swc3. confirmation of macrophage identification used acid phosphatase and phagocytosis activities. during differentiation, swc1 was gradually lost. swc9 was absent on monocytes but up-regulated early. consequently, monocytes were swc1+ swc9- and macrophages were swc1- swc9+. an additional, int ... | 1999 | 10540219 |
| recovery and assay of african swine fever and swine vesicular disease viruses from pig slurry. | assaying samples for infectious virus is more difficult when the sample is toxic to cells used in the assay, e.g. with samples of infected pig slurry. various techniques were compared for the recovery of african swine fever virus (asfv) and swine vesicular disease virus (svdv) in pig slurry. extraction with freon led to 80-100% recovery of svdv added to pig slurry. the assay sensitivity enabled undiluted, centrifuged sample to be put directly onto monolayers of ib-rs2 cells, allowing a minimum d ... | 1999 | 10540248 |
| classical swine fever virus is genetically stable in vitro and in vivo. | phylogenetic analyses of large numbers of classical swine fever strains have revealed a high degree of sequence conservation in the genomic regions examined, suggesting either a recent common ancestor or a low evolution rate. this low variability is in contrast to findings with other rna viruses. to investigate the consequence of this apparent genetic stability on phylogenetic examinations, the belgian field isolate wingene'93 was passaged in pigs as well as in cell culture by various methods. s ... | 1999 | 10542017 |
| differentiation between vaccine strain and field isolates of classical swine fever virus using polymerase chain reaction and restriction test. | the cs vaccine strain of classical swine fever virus is a derivative from the lk parental strain that has been used in russia for more than 30 years. a 10697 nucleotide fragment of the cs strain's genome has been sequenced. sixteen unique restriction markers have been found in the cs genome comparing to the following strains: alfort187, alfort tubingen, brescia, cap, glentorf, ald, gpe-, chinese, c-strain, riems, p97. fourteen of these sites (aflii, avai, cfoi, eco47ii, haeii, kpni, muni, nspi, ... | 1999 | 10547932 |
| mutations abrogating the rnase activity in glycoprotein e(rns) of the pestivirus classical swine fever virus lead to virus attenuation. | classical swine fever (csf) is a severe hemorrhagic disease of swine caused by the pestivirus csf virus (csfv). amino acid exchanges or deletions introduced by site-directed mutagenesis into the putative active site of the rnase residing in the glycoprotein e(rns) of csfv abolished the enzymatic activity of this protein, as demonstrated with an rnase test suitable for detection of the enzymatic activity in crude cell extracts. incorporation of the altered sequences into an infectious csfv clone ... | 1999 | 10559339 |