| 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 |
| csiro's 'natural' vaccines. | | 1999 | 10561787 |
| pilot scale thermal treatment of pig slurry for the inactivation of animal virus pathogens. | this paper describes a pilot scale treatment plant that has been designed and built for the thermal inactivation in pig slurry of two viruses that infect pigs--african swine fever virus (asfv) and swine vesicular disease virus (svdv). the plant treats pig slurry continuously at a rate of up to 100 litres/hour and functions by heating the slurry, maintaining at least 99.99% of the slurry at the required temperature for a minimum period of 5 minutes, and then recovering the heat to raise the tempe ... | 1999 | 10565423 |
| the rna-dependent rna polymerases of different members of the family flaviviridae exhibit similar properties in vitro. | the virus-encoded rna-dependent rna polymerase (rdrp), which is required for replication of the positive-strand rna genome, is a key enzyme of members of the virus family flaviviridae. by using heterologously expressed proteins, we demonstrate that the 77 kda ns5b protein of two pestiviruses, bovine viral diarrhoea virus and classical swine fever virus, and the 100 kda ns5 protein of the west nile flavivirus possess rdrp activity in vitro. as originally shown for the rdrp of hepatitis c virus, r ... | 1999 | 10573150 |
| an african swine fever virus orf with similarity to c-type lectins is non-essential for growth in swine macrophages in vitro and for virus virulence in domestic swine. | an african swine fever virus (asfv) orf, 8cr, with similarity to the c-type lectin family of adhesion proteins has been described in the pathogenic isolate malawi lil-20/1. the similarity of 8cr to cellular and poxvirus genes associated with cell adhesion, cell recognition and virus infectivity suggested that 8cr may be of significance to asfv-host cell interactions. sequence analysis of the 8cr orf from additional pathogenic asfv isolates demonstrated conservation among isolates from both pig a ... | 1999 | 10573162 |
| the effectiveness of routine serological surveillance: case study of the 1997 epidemic of classical swine fever in the netherlands. | the authors describe the value of routine serological surveillance in detecting the introduction of classical swine fever virus into a disease-free population. the first investigation concerned the question of whether the epidemic of classical swine fever (csf), which occurred from 1997 to 1998 in the netherlands, could have been detected using the existing monitoring system for notifiable diseases. the investigation used data from the csf epidemic of 1997/1998 and from the existing monitoring s ... | 1999 | 10588006 |
| classical swine fever: the european experience and a guide for infected areas. | classical swine fever (csf) (hog cholera) virus infection is still of world-wide concern, either because of the direct effects of the disease on swine breeding in areas where the virus is epizootic or enzootic, or as a threat in areas where the virus has been eradicated. the authors provide an overview of the characteristics of the disease. special emphasis is placed on the chronic form of disease, particularly in the late stages of eradication programmes. in the early 1980s, the european union ... | 1999 | 10588007 |
| in vitro inhibition of the replication of haemorrhagic septicaemia virus (vhsv) and african swine fever virus (asfv) by extracts from marine microalgae. | we have screened for in vitro inhibition of viral replication with extracts from the following marine microalgae: porphyridium cruentum, phaeodactylum tricornutum, tetraselmis suecica, chlorella autotrophica, dunaliella tertiolecta, dunaliella bardawil, isochrysis galbana, isochrysis galbana var tiso, ellipsoidon sp. and tetraselmis tetrathele. we have used as viral models two enveloped viruses of significant economic importance, the viral hemorrhagic septicemia virus (vhsv) of salmonid fish and ... | 1999 | 10588334 |
| vaccination with a single dose of a recombinant porcine adenovirus expressing the classical swine fever virus gp55 (e2) gene protects pigs against classical swine fever. | a recombinant porcine adenovirus (rpav) with the gp55 (e2) gene from the classical swine fever virus (csfv) 'weybridge' strain inserted into the right hand end of the pav serotype 3 (pav3) genome was constructed. expression of gp55 was directed by the major late promoter and tri-partite leader sequences located and cloned from pav3. no compensatory deletions of pav dna sequences were made. vaccination of outbred pigs with a single dose of the recombinant virus (rpav-gp55) resulted in complete pr ... | 2000 | 10590324 |
| phylogenetic comparison and molecular epidemiology of classical swine fever virus. | the genetic diversity of classical swine fever virus (csfv) was studied by rt-pcr amplification and sequencing of a 409 bp fragment of the ns5b polymerase region. a total of 106 viruses isolated from 20 countries over a period of 52 years (1945-1997) were included in the phylogenetic study. the results showed that the viruses could be divided into two main groups. group 1 consisted of asian and south american isolates from the 1980s, as well as of old european and american isolates. group 2 cons ... | 1999 | 10595410 |
| classical swine fever virus in plasma and peripheral blood mononuclear cells of acutely infected swine. | the distribution of classical swine fever virus (csfv) in plasma, monocytes, t and b lymphocytes in peripheral blood was monitored during experimentally induced acute classical swine fever infection in piglets. six piglets were infected with 10(3.8) tcid50 of virus and blood samples taken up to 18 days post-inoculation (p.i.). infectious virus was detected in monocytes, t and b lymphocytes to similar titres in five of the six infected piglets. infectious virus was detected earlier in plasma than ... | 1999 | 10605368 |
| determination of the onset of the herd-immunity induced by the e2 sub-unit vaccine against classical swine fever virus. | for a recently developed e2 subunit vaccine against classical swine fever (csf), the reduction in transmission, at different moments after vaccination, was assessed by animal experiments and statistical calculations. two experiments were performed to estimate the reproduction ratio r. experiment 1 consisted of three groups and experiment 2 of two groups each of 10 pigs. in four of these groups, all pigs were vaccinated intramuscularly with the vaccine. the pigs in the fifth group remained unvacc ... | 2000 | 10618535 |
| laboratory decision-making during the classical swine fever epidemic of 1997-1998 in the netherlands. | the national reference laboratory for classical swine fever (csf) virus in the netherlands examined more than two million samples for csf virus or serum antibody during the csf epizootic of 1997-1998. the immense amount of samples and the prevalence of border disease (bd) virus and bovine viral diarrhoea (bvd) virus infections in dutch pig herds necessitated the diagnostic efforts of the laboratory to be focused on generating csf specific test results throughout the eradication campaign. detecti ... | 1999 | 10619155 |
| transmission of classical swine fever virus within herds during the 1997-1998 epidemic in the netherlands. | in this paper, we describe the transmission of classical swine fever virus (csf virus) within herds during the 1997-1998 epidemic in the netherlands. in seven herds where the infection started among individually housed breeding stock, all breeding pigs had been tested for antibodies to csf virus shortly before depopulation. based upon these data, the transmission of csf virus between pigs was described as exponential growth in time with a parameter r, that was estimated at 0.108 (95% confidence ... | 1999 | 10619156 |
| quantification of the transmission of classical swine fever virus between herds during the 1997-1998 epidemic in the netherlands. | in this study, we describe a method to quantify the transmission of classical swine fever virus (csfv) between herds from data collected during the 1997-1998 epidemic in the netherlands. from the contacts between infected herds and the serological findings shortly before depopulation, we estimated the week of virus introduction and the length of the period over which the herd emitted virus for each csfv-infected herd. from these data, we estimated the infection-rate parameter beta (the average n ... | 1999 | 10619157 |
| the 1997-1998 classical swine fever epidemic in the netherlands--a survival analysis. | the aim of this analysis was to characterise the temporal pattern of infection during the 1997/98 classical swine fever (csf) epidemic in the netherlands and hence identify and quantify risk factors for infection in different enterprise types and areas. survival analysis and cox proportional hazards regression were used to describe the epidemic. substantial differences in temporal survival patterns (herd breakdown rate) were found between areas where different control policies operated. factors ... | 1999 | 10619158 |
| spatial and stochastic simulation to evaluate the impact of events and control measures on the 1997-1998 classical swine fever epidemic in the netherlands. ii. comparison of control strategies. | using the spatial, temporal and stochastic simulation model intercsf, several alternative pre-emptive slaughter strategies that could have been applied in the dutch classical swine fever (csf) epidemic of 1997-1998 were evaluated. furthermore, effects of changes in some disease-spread and disease-control parameters were studied. intercsf simulates the spread of csf between farms through local spread and contacts (animals, transport and persons). disease spread is affected by control measures imp ... | 1999 | 10619161 |
| an african swine fever virus erv1-alr homologue, 9gl, affects virion maturation and viral growth in macrophages and viral virulence in swine. | the african swine fever virus (asfv) genome contains a gene, 9gl, with similarity to yeast erv1 and alr genes. erv1 has been shown to function in oxidative phosphorylation and in cell growth, while alr has hepatotrophic activity. 9gl encodes a protein of 119 amino acids and was highly conserved at both nucleotide and amino acid levels among all asfv field isolates examined. monospecific rabbit polyclonal antibody produced to a glutathione s-transferase-9gl fusion protein specifically immunopreci ... | 2000 | 10627538 |
| regulation of calcineurin by growth cone calcium waves controls neurite extension. | growth cones generate spontaneous transient elevations of intracellular ca(2+) that regulate the rate of neurite outgrowth. here we report that these ca(2+) waves inhibit neurite extension via the ca(2+)-dependent phosphatase calcineurin (cn) in xenopus spinal neurons. pharmacological blockers of cn (cyclosporin a and deltamethrin) and peptide inhibitors of cn [the xenopus cn (xcn) autoinhibitory domain and african swine fever virus protein a238l] block the ca(2+)-dependent reduction of neurite ... | 2000 | 10627609 |
| african swine fever virus ep153r open reading frame encodes a glycoprotein involved in the hemadsorption of infected cells. | the open reading frame ep153r, located within the ecori e' fragment of the african swine fever (asf) virus genome, is predicted to encode a membrane protein of 153 amino acids that presents significant homology to the n-terminal region of several cd44 molecules. ep153r contains multiple putative sites for n-glycosylation, phosphorylation, and myristoylation, a central transmembrane region, a c-type animal lectin-like domain, and a cell attachment sequence. transcription of ep153r takes place at ... | 2000 | 10639320 |
| characterization of the african swine fever virus protein p49: a new late structural polypeptide. | the open reading frame b438l, located within the ecori b fragment of the african swine fever virus genome, is predicted to encode a protein of 438 amino acids with a molecular mass of 49.3 kda. it presents a cell attachment rgd (arg-gly-asp) motif but no other significant similarity to protein sequences in databases. northern blot and primer extension analysis showed that b438l is transcribed only at late times during virus infection. the b438l gene product has been expressed in escherichia coli ... | 2000 | 10640542 |
| observations on the quasispecies composition of three animal pathogenic rna viruses. | the quasispecies nature of three animal pathogenic rna viruses of field origin was examined by testing variants of classical swine fever virus (csfv) originating from geographically different areas, feline coronavirus (fcov) detected from the same animal by successive sampling, and rabbit haemorrhagic disease virus (rhdv) originating from successive outbreaks in the same geographic area. clinical samples were investigated using reverse transcriptase polymerase chain reaction (rt-pcr) and ensuing ... | 1999 | 10641337 |
| infections with flaviviridae. | the family of the flaviviridae contains 3 genera: (i) the hepaciviruses, to which belongs hepatitis c virus (hcv), (ii) the flaviviruses and (iii) the pestiviruses. over 140 million people, more than four times the number of hiv-positive individuals, are chronically infected with the hcv. hepatitis g virus (hgv) has not yet been assigned to a genus. the impact of this recently discovered virus is yet to be established. infections with flaviviruses such as yellow fever virus (yfv), dengue fever v ... | 1999 | 10655776 |
| biochemical requirements of virus wrapping by the endoplasmic reticulum: involvement of atp and endoplasmic reticulum calcium store during envelopment of african swine fever virus. | enwrapment by membrane cisternae has emerged recently as a mechanism of envelopment for large enveloped dna viruses, such as herpesviruses, poxviruses, and african swine fever (asf) virus. for both asf virus and the poxviruses, wrapping is a multistage process initiated by the recruitment of capsid proteins onto membrane cisternae of the endoplasmic reticulum (er) or associated er-golgi intermediate membrane compartments. capsid assembly induces progressive bending of membrane cisternae into the ... | 2000 | 10666244 |
| [serosurveillance of notifiable veterinary diseases in wild boar in the netherlands]. | during the hunting season 1996-1999, blood samples were collected from wild boar shot in the netherlands. sera were screened for presence of antibodies against classical swine fever virus (csfv), swine vesicular disease virus (svdv), aujeszky's disease virus (adv), and trichinella spiralis. the results indicate that csfv, svdv, and adv are uncommon in the wild boar population. therefore, it seems that csfv, svdv, and adv infection in the wild boar population is not an important reservoir in the ... | 2000 | 10666784 |
| effects of chlorine, iodine, and quaternary ammonium compound disinfectants on several exotic disease viruses. | the effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. the viruses used were four enveloped viruses (vesicular stomatitis virus, african swine fever virus, equine viral arteritis virus, and porcine reproductive and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (svdv) ... | 2000 | 10676896 |
| within-farm spread of classical swine fever virus--a blueprint for a stochastic simulation model. | a stochastic simulation model to investigate the transmission of classical swine fever (csf) virus within an infected farm is described. the model is structured according to the processes that occur within and between management groups (pig units or houses). it uses the individual pig as the unit of interest and estimates the number of animals in the states 'susceptible', 'infected', 'infectious', and 'removed' for each day of the disease incident. probabilities are assigned to the transitions b ... | 2000 | 10682386 |
| protection of pigs against classical swine fever with dna-delivered gp55. | classical swine fever virus causes significant mortality and morbidity in commercial piggeries in many countries in europe and asia. the protective antigen, gp55, is highly conformation-dependent and thus killed virus or bacterially produced proteins are not protective. this report demonstrates that dna vaccination with the gene encoding gp55 can provide protective immunity with inoculation of two doses of 25 microg dna or a single shot of 200 microg. furthermore, the dna can be delivered intram ... | 2000 | 10699343 |
| [laboratory findings during the classic swine fever epidemic of 1997-1998]. | the results of the laboratory tests carried out by the institute for animal science and health (id-lelystad), the netherlands, on samples collected during the classical swine fever (csf) epidemic 1997-1998 are summarized in this article. the relevance of the different laboratory tests and various samples collected on the eradication of csf during an outbreak is evaluated. | 2000 | 10705606 |
| classical swine fever virus e(rns) deletion mutants: trans-complementation and potential use as nontransmissible, modified, live-attenuated marker vaccines. | an sk6 cell line (sk6c26) which constitutively expressed the glycoprotein e(rns) of classical swine fever virus (csfv) was used to rescue csfv e(rns) deletion mutants based on the infectious copy of csfv strain c. the biochemical properties of e(rns) from this cell line were indistinguishable from those of csfv e(rns). two e(rns) deletion mutants were constructed, virus flc23 and virus flc22. virus flc23 encoded only the utmost n- and c-terminal amino acids of e(rns) (deletion of 215 amino acids ... | 2000 | 10708411 |
| recombinant classical swine fever (csf) viruses derived from the chinese vaccine strain (c-strain) of csf virus retain their avirulent and immunogenic characteristics. | two recombinant classical swine fever (csf) viruses (flc2, flc3) transcribed from a dna copy of the genome of the chinese (c) strain, a csf virus vaccine strain, were characterized in vivo in rabbits and pigs. rabbits were inoculated intravenously with flc2 or flc3, the parent c-strain virus, a biologically cloned c-strain or csf virus strain brescia (c.1.1.1). after 24-96 h fever was detected in the rabbits inoculated with the different c-strain viruses. apart from those in the control group, a ... | 2000 | 10738091 |
| transient classical swine fever virus infection in wild boar piglets partially protected by maternal antibodies. | an experimental study was conducted to investigate the clinical course of classical swine fever (csf) in wild boar piglets partially protected by maternal antibodies. five healthy wild boar piglets with a low serum titre of colostral antibodies against csf virus were challenged with virulent csf virus at the age of three months. apart of reduced food intake and diarrhoea no major clinical symptoms were noticed after challenge. these signs were seen during the second and third week of infection, ... | 2000 | 10743336 |