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proportions and phenotypic expression of peripheral blood leucocytes in pigs vaccinated with an attenuated c strain and a subunit e2 vaccine against classical swine fever.the influence of an attenuated classical swine fever virus c strain vaccine and a subunit e2 vaccine against classical swine fever on the peripheral blood leucocyte proportion and phenotypic expression in 12-week-old pigs was studied. the c strain was amplified in minipig kidney cell culture and final product contained 10(4 +/- 0.15) tcid50/ml, while the subunit vaccine contained 32 microg per dose of gp e2. haematological findings showed that the vaccines did not cause leucopenia or lymphocytop ...200312916689
infection of porcine reproductive and respiratory syndrome virus suppresses the antibody response to classical swine fever virus vaccination.the effects of porcine reproductive and respiratory syndrome virus (prrsv) infection on the antibody response to vaccination with classical swine fever (csf) vaccine in piglets were investigated. piglets were inoculated intranasally with the prrsv bj-4 strain, and then vaccinated intramuscularly with csf vaccine 2 days later. control animals were either vaccinated with csf vaccine or infected with prrsv alone. time course of the antibody response against either prrsv or csf vaccine was measured. ...200312935755
highly sensitive pcr assay for routine diagnosis of african swine fever virus in clinical samples.this work provides a novel, highly sensitive, hot start pcr method for rapid and specific detection of african swine fever virus (asfv) that can be used as a routine diagnostic test for asfv in surveillance, control, and eradication programs. a confirmatory test of the specificity of this method based on restriction endonuclease analysis was also developed.200312958285
analysis of hepatitis c virus/classical swine fever virus chimeric 5'ntrs: sequences within the hepatitis c virus ires are required for viral rna replication.hepatitis c virus (hcv) is classified in the genus hepacivirus of the family flaviviridae, whose members have a single-stranded rna genome of positive polarity, which encodes a single polyprotein. within this family, hcv is closely related to viruses of the genus pestivirus, which includes classical swine fever virus (csfv). translation of the hepaci- and pestiviral polyprotein is initiated by internal entry of ribosomes, promoted by the 5'ntr. the secondary and tertiary rna structures of the hc ...200312810870
classical swine fever--an update.classical swine fever (csf) is a serious and contagious viral disease of pigs and wild boar with a widespread worldwide distribution. the immunopathology of the disease is poorly understood, but the ability of the csf virus to infect cells without triggering apoptosis and to kill uninfected cells is probably highly significant. the virus may be spread by various direct and indirect methods, but in most cases the exact mechanisms involved in local spread between farms are not known. excellent dia ...200313129664
spontaneous excision of bac vector sequences from bacmid-derived baculovirus expression vectors upon passage in insect cells.repeated baculovirus infections in cultured insect cells lead to the generation of defective interfering viruses (dis), which accumulate at the expense of the intact helper virus and compromise heterologous protein expression. in particular, autographa californica multicapsid nucleopolyhedovirus (acmnpv) dis are enriched in an origin of viral dna replication (ori) not associated with the homologous regions (hrs). this non-hr ori is located within the coding sequence of the non-essential p94 gene ...200313679600
detection of porcine teschoviruses and enteroviruses by lightcycler real-time pcr.porcine picornaviruses comprising at least 23 serotypes grouped into six species were described as causative agents of neurological disorders, reproductive failure, and aphthae-like dermal lesions of swine. other viruses such as classical swine fever virus (csfv), african swine fever virus, pseudorabies virus (prv), vesicular stomatitis virus, vesicular exanthema virus, porcine respiratory and reproductive syndrome virus, and porcine parvovirus (ppv) may cause diseases with similar clinical symp ...200314500127
high-pressure freezing in the study of animal pathogens.high-pressure freezing is applicable to both morphological and immunocytochemical studies. we are investigating the morphogenesis of foot-and-mouth disease virus and african swine fever virus by the use of high-pressure freezing of infected cells. foot-and-mouth disease virus particles are not detected in sections of conventionally immersion-fixed infected cells, but when the cells are prepared by high-pressure freezing, newly formed virions are readily seen throughout the cell. we report two me ...200314516363
genetic typing of recent classical swine fever virus isolates from croatia.during a period of 5 years (1997-2001) several outbreaks of classical swine fever (csf) were recorded in croatia. for genetic typing, fragments of 150 nucleotides within the 5'-non-translated region (5'-ntr) and 190 nucleotides within the e2 glycoprotein coding gene of nine field isolates that were derived from domestic pigs and wild boars were used. for better epizootiological understanding, isolates from other european countries were included in the study. the results show that the isolates be ...200314516705
rna-dependent rna polymerase activity of classical swine fever virus ns5b protein expressed in natural host cells.the ns5b gene, cloned from classical swine fever virus (csfv) genome, was expressed in porcine kidney cells pk-15, natural host of csfv. in purifying cytoplasmic extracts from these cells by means of different concentrations of salt, glycerol and detergent four fractions, namely crude supernatant (sc) and different purified supernatants (s1, s2 and s3) were obtained. using western blot analysis the ns5b protein was found in all these fractions, showing that it was soluble in both higher and lowe ...200314524473
evaluation of the oral immunisation of wild boar against classical swine fever in baden-württemberg.the oral immunisation of wild boar against classical swine fever (csf) in baden-württemberg is described and evaluated. the bait vaccine based on the csf virus (csfv) strain "c" proved to be safe in wild boar of all age classes. the modified immunisation procedure consisting of three double vaccinations per year was very effective. csfv was not detected beyond the second immunisation campaign. the average rate of seropositive wild boar diagnosed over all immunisation periods was 49.2%. the serop ...200314526465
evaluation of the antiviral and antimicrobial activities of triterpenes isolated from euphorbia segetalis.a phytochemical reinvestigation of the whole plant of euphorbia segetalis yielded five tetracyclic triterpenes: 3beta-hydroxy-cycloart-25-en-24-one (1), cycloart-25-ene-3beta,24-diol (2), cycloart-23-ene-3beta,25-diol (3), lanosta-7,9(11),24-trien-3beta-ol (4) and lanosta-7,9(11),24(31)-trien-3beta-ol (5). beta-acetoxy-cycloart-25-en-24-one (1a) and glutinol (6), lupenone (7), dammaranodienol (9), cycloartenol acetate (10), 24-methylenecycloartanol acetate (11) and beta-sitosterol (12), isolated ...200314526920
role of birds in transmission of classical swine fever virus.active transmission of classical swine fever virus (csfv) was studied in six birds (five ravens, one hooded crow) and two laying hens. cloacal swabs, blood and organs of birds and hens as well as blood and organ samples of pigs which had been fed with faeces derived from csfv infected birds or which had come in contact with faeces of infected hens were negative for csfv. none of the animals seroconverted during the study. this result demonstrates that active virus transmission by these animals i ...200314535936
evidence for the evolution of ascoviruses from iridoviruses.ascoviruses (family ascoviridae) are large, enveloped, double-stranded (ds)dna viruses that attack lepidopteran larvae and pupae, and are unusual in that they are transmitted by parasitic wasps during oviposition. previous comparisons of dna polymerase sequences from vertebrate and invertebrate viruses suggested that ascoviruses are closely related to iridoviruses. this relationship was unexpected because these viruses differ markedly in virion symmetry, genome configuration and cellular patholo ...200314573805
a pilot study of therapeutic vaccination with envelope protein e1 in 35 patients with chronic hepatitis c.new treatments are needed for chronic hepatitis c patients in whom viral clearance cannot be achieved. thirty-five chronic hepatitis c patients (genotype 1) were randomized to receive 20 mug of recombinant hcv e1 (e1) (n = 26) or placebo (n = 9) intramuscularly at weeks 0, 4, 8, 12, and 24. thirty-four then received open-label e1 vaccine at weeks 50, 53, 56, 59, 62, and 65. twenty-four patients (12 men, 12 women; mean age, 52 y; 18 interferon-based treatment failures; mean baseline alanine amino ...200314578869
expression at mrna level of cytokines and a238l gene in porcine blood-derived macrophages infected in vitro with african swine fever virus (asfv) isolates of different virulence.porcine macrophage cultures were infected with two asfv isolates of variable virulence and mrna levels of several relevant macrophage-derived cytokines were quantified by real time pcr. at six hours post infection, a clear enhancement of mrna expression of tnfalpha, il6, il12 and il15 was observed in macrophages infected with the low virulent asfv/nh/p68 (nhv) when compared to those infected with the highly virulent asfv/l60 (l60). the sequence of the a238l gene homologue to the cellular ikappab ...200314579171
quantification of the effect of control strategies on classical swine fever epidemics.emergency vaccination during an epidemic of classical swine fever virus (csfv) has become a serious option because of the ethical problems of strategies with massive culling and the availability of a marker vaccine that reduces virus transmission. here we present a model of between-herd csfv transmission, which quantifies the effect of control strategies with and without vaccination. we estimate the model parameters from data of the dutch csfv epidemic of 1997/1998. with the model, a set of cont ...200314583170
construction of an infectious chimeric classical swine fever virus containing the 5'utr of bovine viral diarrhea virus, and its application as a universal internal positive control in real-time rt-pcr.rt-pcr is used widely as a diagnostic method to detect and differentiate pestiviruses. the construction of two chimeric classical swine fever virus (csfv) recombinants based on a marker virus constructed previously [j. virol. 72 (1998) 5318-5322] is described. these viruses, termed va187cat_5utrbvd and va187cat_iresbvd, contain the entire 5' untranslated region (5'utr) or the internal ribosome entry site (ires) of bovine viral diarrhea virus (bvdv), respectively. both chimeric viruses proved to ...200314599682
assessment of the use of gross lesions at post-mortem to detect outbreaks of classical swine fever.the performance of pathological findings as a diagnostic tool for the detection of classical swine fever (csf) outbreaks during the 1997/1998 csf-epidemic in the netherlands was evaluated by constructing and analysing receiver operating characteristic (roc) curves. this was done at the individual pig level and at the submission level (a group of pigs from the same herd submitted together for post-mortem investigation). at post-mortem examination, the tonsils, spleen, ileo-caecal valve and renal ...200314599782
vaccinology of classical swine fever: from lab to field.there are two types of classical swine fever vaccines available: the classical live and the recently developed e2 subunit vaccines. the live chinese strain vaccine is the most widely used. after a single vaccination, it confers solid immunity within a few days that appears to persist lifelong. the e2 subunit vaccine induces immunity from approximately 10-14 days after a single vaccination. the immunity may persist for more than a year, but is then not complete. the chinese strain vaccine may est ...200314599784
protection of pigs against 'in contact' challenge with classical swine fever following oral or subcutaneous vaccination with a recombinant porcine adenovirus.a recombinant porcine adenovirus expressing the classical swine fever virus (csfv) gp55 gene (rpadv-gp55) was administered to commercially available outbred pigs via the subcutaneous or oral route and their susceptibility to 'in contact' challenge with classical swine fever determined. animals vaccinated subcutaneously with a single dose of recombinant vaccine and challenged by 'in contact' exposure were protected from disease, whereas pigs given an equivalent single oral dose did not survive ch ...200314602208
host immune responses against hog cholera virus in pigs treated with an ionized alkali mineral complex.to determine the immune responses in pigs to hog cholera virus after treatment with an ionized alkali mineral complex (iamc), 40 healthy pigs (28-32 days old) from a commercial swine farm were purchased and housed into 4 groups (n=10 each). all pigs were vaccinated intramuscularly (1 ml) with an attenuated live hog cholera virus (hcv, lom strain) at 28-32 days old and challenged with a virulent hog cholera virus at 8 weeks after vaccination. each group was treated with powerfeel sprayed diet as ...200212819381
regulation of apoptosis in african swine fever virus-infected macrophages.a number of viruses have evolved antiapoptotic mechanisms to promote infected-cell survival, either to ensure efficient productive viral replication or to promote long-term survival of virus-infected cells. recent studies identified critical african swine fever virus genes involved in the complex regulation of asfv-host interactions. here we review the present knowledge of the recently identified asfv genes with special attention to those which affect viral virulence, host range, and pathogenesi ...200212805900
[detection of antibody against hepatitis c virus first envelope (hcv-e1) protein and its clinical application].to study the antibody against hepatitis c virus first envelope (hcv-e1) protein in the sera from patients with hcv and to evaluate the application of hcv-e1 antigen in detection of hcv antibody.200212665917
[cloning of the major antigen region of e2 gene of hog cholera virus and expression in escherichia coli].the major antigen region of e2 gene of hog cholera prevalent strain (guangxi yuling strain) and chinese hog cholera lapinised virus (c-strain) derived from hog and rabbit spleen tissue, was amplified by reverse transcription polymerase chain reaction(rt-pcr) and the nested polymerase chain reaction (npcr). after the amplified fragments were cloned into the expression vector pproex-htb, the recombinant plasmids pproex-gxyl and pproex-c were obtained. the insert position, the size and the reading ...200212561208
the influence of viral coding sequences on pestivirus ires activity reveals further parallels with translation initiation in prokaryotes.classical swine fever virus (csfv) is a member of the pestivirus family, which shares many features in common with hepatitis c virus (hcv). it is shown here that csfv has an exceptionally efficient cis-acting internal ribosome entry segment (ires), which, like that of hcv, is strongly influenced by the sequences immediately downstream of the initiation codon, and is optimal with viral coding sequences in this position. constructs that retained 17 or more codons of viral coding sequence exhibited ...200212515388
an experimental infection to investigate the indirect transmission of classical swine fever virus by excretions of infected pigs.in this experiment transmission of classical swine fever (csf) virus via excretions of infected pigs was investigated under experimental conditions. five pairs of pigs were experimentally infected with csf virus. eight days after experimental infection, when all pigs were viraemic for at least 3 days, the pens were depopulated and 20 h later, restocked with five pairs of susceptible pigs which stayed in these pens for 35 days. during the first 3 weeks of the experiment, the pens were neither cle ...200212489714
simulated effect of pig-population density on epidemic size and choice of control strategy for classical swine fever epidemics in the netherlands.we examined the importance of pig-population density in the area of an outbreak of classical swine fever (csf) for the spread of the infection and the choice of control measures. a spatial, stochastic, dynamic epidemiological simulation model linked to a sector-level market-and-trade model for the netherlands were used. outbreaks in sparsely and densely populated areas were compared under four different control strategies and with two alternative trade assumptions. the obligatory control strateg ...200212450686
candidate peptide vaccine induced protection against classical swine fever virus.former investigations demonstrated that the envelope glycoprotein e2 could protect pigs from classical swine fever virus (csfv). based on these findings, we prepared synthetic peptide vaccine using e2 n-terminal antigenic units b/c and hoped to induce protective activity against lethal challenge of virulent csfv strain shimen. five overlapped peptides sequence-covering amino acids 693-777 on e2 of shimen were synthesized and then conjugated with bovine serum albumin (bsa), respectively. in the v ...200212450690
functional properties of a monoclonal antibody inhibiting the hepatitis c virus rna-dependent rna polymerase.the hepatitis c virus (hcv) rna-dependent rna polymerase (rdrp), represented by nonstructural protein 5b (ns5b), has recently emerged as a promising target for antiviral intervention. here, we describe the isolation, functional characterization, and molecular cloning of a monoclonal antibody (mab) inhibiting the hcv rdrp. this mab, designated 5b-12b7, binds with high affinity to a conformational epitope in the palm subdomain of the hcv rdrp and recognizes native ns5b expressed in the context of ...200211641406
the g5r (d250) gene of african swine fever virus encodes a nudix hydrolase that preferentially degrades diphosphoinositol polyphosphates.the african swine fever virus (asfv) g5r gene encodes a protein containing a nudix hydrolase motif which in terms of sequence appears most closely related to the mammalian diadenosine tetraphosphate (ap4a) hydrolases. however, purified recombinant g5r protein (g5rp) showed a much wider range of nucleotide substrate specificity compared to eukaryotic ap4a hydrolases, having highest activity with gtp, followed by adenosine 5'-pentaphosphate (p5a) and dgtp. diadenosine and diguanosine nucleotides w ...200211773415
novel swine virulence determinant in the left variable region of the african swine fever virus genome.previously we have shown that the african swine fever virus (asfv) nl gene deletion mutant e70deltanl is attenuated in pigs. our recent observations that nl gene deletion mutants of two additional pathogenic asfv isolates, malawi lil-20/1 and pr4, remained highly virulent in swine (100% mortality) suggested that these isolates encoded an additional virulence determinant(s) that was absent from e70. to map this putative virulence determinant, in vivo marker rescue experiments were performed by in ...200211884534
modeling and real-time prediction of classical swine fever epidemics.we propose a new method to analyze outbreak data of an infectious disease such as classical swine fever. the underlying model is a two-type branching process. it is used to deduce information concerning the epidemic from detected cases. in particular, the method leads to prediction of the future course of the epidemic and hence can be used as a basis for control policy decisions. we test the model with data from the large 1997-1998 classical swine fever epidemic in the netherlands. it turns out ...200211892689
a single amino acid is critical for the expression of b-cell epitopes on the helicase domain of the pestivirus ns3 protein.truncated ns3 proteins, expressed by recombinant baculoviruses, were used to investigate the location of conserved b-cell epitopes on this non-structural bovine viral diarrhoea virus (bvdv) protein. a goat anti-pestivirus antiserum, and a panel of anti-ns3 monoclonal antibodies, including the bvdv-1 specific antibody p1d8, were used to verify the presence or absence of the epitopes. interestingly, the monoclonal antibodies reacted only with the truncated protein encompassing the helicase domain ...200211900844
[the contagiousness of the pestivirus and foot and mouth disease virus]. 200211905240
african swine fever virus iap-like protein induces the activation of nuclear factor kappa b.african swine fever virus (asfv) encodes a homologue of the inhibitor of apoptosis (iap) that promotes cell survival by controlling the activity of caspase-3. here we show that asfv iap is also able to activate the transcription factor nf-kappab. thus, transient transfection of the viral iap increases the activity of an nf-kappab reporter gene in a dose-responsive manner in jurkat cells. similarly, stably transfected cells expressing asfv iap have elevated basal levels of c-rel, an nf-kappab-dep ...200211907233
electrochemical characterization of screen-printed carbonaceous electrodes for the determination of peroxidase activity in novel screen-printed flow-through modules.a novel totally screen-printed flow-through cell for immunoanalysis is presented. it contained screen-printed carbonaceous electrodes, which allowed the determination of peroxidase activity through the electrochemical reduction of p-benzoquinone. as different electrode materials differ strongly in their electrochemical properties, electrodes resulting from various screen-printable carbonaceous pastes were characterized using the hydroquinone/ p-benzoquinone redox couple. for most of the electrod ...200211936093
reconstitution of hepatitis c virus envelope glycoproteins into liposomes as a surrogate model to study virus attachment.the envelope glycoproteins, e1 and e2, of hepatitis c virus (hcv) assemble intracellularly to form a noncovalent heterodimer that is expected to be essential for viral assembly and entry. however, due to the lack of a cell culture system supporting efficient hcv replication, it is very difficult to obtain relevant information on the functions of this glycoprotein oligomer. to get better insights into its biological and biochemical properties, hcv envelope glycoprotein heterodimer expressed by a ...200211937498
development of a rapid in vitro protein refolding assay which discriminates between peptide-bound and peptide-free forms of recombinant porcine major histocompatibility class i complex (sla-i).the extracellular domains of swine leukocyte antigen class i (sla-i, major histocompatibility complex protein class i) were cloned and sequenced for two haplotypes (h4 and h7) which do not share any alleles based on serological typing, and which are the most important in danish farmed pigs. the extracellular domain of sla-i was connected to porcine beta2 microglobulin by glycine-rich linkers. the engineered single-chain proteins, consisting of fused sla-i and beta2 microglobulin, were overexpres ...200211943330
orf virus encodes a functional dutpase gene.the present study is the first report on the functional activity of a parapoxvirus-encoded dutpase. the dutpase gene of the attenuated orf virus (orfv), strain d1701, was expressed as a bacterial thioredoxin fusion protein. in vitro assays showed that orfv dutpase was highly specific for dutp as substrate. the enzyme was active over a broad ph range (ph 6.0-9.0), with maximal enzymatic activity at ph 7.0 in the presence of mg(2+) cations. kinetic studies of the recombinant orfv dutpase revealed ...200211961258
pestivirus internal ribosome entry site (ires) structure and function: elements in the 5' untranslated region important for ires function.the importance of certain structural features of the 5' untranslated region of classical swine fever virus (csfv) rna for the function of the internal ribosome entry site (ires) was investigated by mutagenesis followed by in vitro transcription and translation. deletions made from the 5' end of the csfv genome sequence showed that the ires boundary was close to nucleotide 65: thus, the ires includes the whole of domain ii but no sequences upstream of this domain. deletions which invaded domain i ...200211967318
rate of inter-herd transmission of classical swine fever virus by different types of contact during the 1997-8 epidemic in the netherlands.in this study we quantified the rate at which classical swine fever had been transmitted by several different types of inter-herd contact during the 1997-8 epidemic in the netherlands. during that epidemic 428 csfv-infected pig herds were detected, 403 of which were include in this study. the estimated rates of transmission were 0.065 per shipment of live pigs, 0.011 per contact by a pig transportation lorry, 0.0068 per person contact, 0.0007 per dose of semen, 0.0065 per contact with a potentia ...200212002547
within- and between-pen transmission of classical swine fever virus: a new method to estimate the basic reproduction ratio from transmission experiments.we present a method to estimate basic reproduction ratio r0 from transmission experiments. by using previously published data of experiments with classical swine fever virus more extensively, we obtained smaller confidence intervals than the martingale method used in the original papers. moreover, our method allows simultaneous estimation of a reproduction ratio within pens r0w and a modified reproduction ratio between pens r'0b. resulting estimates of r0w and r'0b for weaner pigs were 100 (95% ...200212002548
apoptosis induced in an early step of african swine fever virus entry into vero cells does not require virus replication.permissive vero cells develop apoptosis, as characterized by dna fragmentation, caspases activation, cytosolic release of mitochondrial cytochrome c, and flow cytometric analysis of dna content, upon infection with african swine fever virus (asfv). to determine the step in virus replication that triggers apoptosis, we used uv-inactivated virus, inhibitors of protein and nucleic acid synthesis, and lysosomotropic drugs that block virus uncoating. asfv-induced apoptosis was accompanied by caspase- ...200212009879
identification of the principal serological immunodeterminants of african swine fever virus by screening a virus cdna library with antibody.protective immunity to african swine fever virus (asfv) may involve a combination of both serological and cellular mechanisms. this work is focused on the identification of the possible relevant serological immunodeterminants of immunity. thus, 14 serological immunodeterminants of asfv have been characterized by exhaustive screening of a representative lambda phage cdna expression library of the tissue culture-adapted ba71v strain of asfv. the library was constructed using rna extracted from ver ...200212029148
establishment and application of bicistronic classical swine fever virus genomes for foreign gene expression and complementation of e2 deletion mutants.bicistronic genomes of the classical swine fever virus (csfv) strain alfort/187 (a187) were established by insertion of a second cistron consisting of an internal ribosome entry site of the encephalomyocarditis virus and a coding sequence in the 3' untranslated region of the genome. introduction of the selectable marker gene for neomycin phosphotransferase into the second cistron of the csfv replicon a187 delta e2-cat allowed the establishment of porcine sk-6 cell lines constitutively expressing ...200212034484
[procoagulant activity of blood cells in pestivirus infection].an increased level of procoagulant activity (pca) in leukocytes of pigs with acute classical swine fever (csf) was observed on day 4 postinfection; pca level normalized during the moribund state. csf vaccine strain either did not induce an increase of pca level or induced an increase that persisted for at least 11 days. time course of pca changes in the leukocytes from sheep infected with borderline sheep disease was similar to the time course of pca in acute csf. in vitro each of the pestivirus ...200212046460
oral immunisation of wild boar against classical swine fever: concluding analysis of the recent field trials in germany.the recent oral immunisation trials in wild boar against classical swine fever (csf) in germany are described and evaluated in summary. after the first field study in lower saxony from 1993-1995 further immunisation trials started in mecklenburg-western pomerania, brandenburg, lower saxony, baden-württemberg and saxony-anhalt. the immunisation strategies and the size of the vaccination zones were different in the individual federal states. in principle, the bait vaccine based on the csf virus st ...200212058591
t-helper cells from naive to committed.t-helper cells play a central role in the onset and regulation of the antigen-specific immune response. in swine, two subpopulations of cd4 positive t-helper cells could be defined in extra-thymic compartments. both differ in the surface antigen expression of distinct antigens. besides the cd4(+)cd8(-) t-helper cell subpopulation representing the phenotype of t-helper cells known from other species, in swine cd4(+) t-helper cells exist showing expression of cd8alpha and mhcii molecules.in primar ...200212072228
leukopenia and thrombocytopenia in pigs after infection with bovine viral diarrhoea virus-2 (bvdv-2).the aim of this study was to investigate whether bovine viral diarrhoea virus-2 (bvdv-2) is pathogenic for pigs, which organs become infected and whether or to which extent the virus is excreted into the environment. ten pigs were observed for clinical reactions after infection with a bvdv-2 strain, that has been shown to be pathogenic in calves under experimental conditions. samples were taken to monitor thrombocyte and leukocyte counts as well as antibody development. post mortem examinations ...200212073495
cloning and regulation of the promoter of pseudorabies virus (tnl strain) glycoprotein e gene.the nucleotide sequence upstream to the glycoprotein e (ge) gene of pseudorabies virus (prv, tnl strain) was cloned from the genomic virus dna by polymerase chain reaction (pcr) and its dna sequences were determined. the dna segment, which was supposed to contain the ge promoter, was subcloned into a chloramphenicol acetyltransferase (cat) reporter gene and the resulting plasmid was named pgep-b-cat. to examine the promoter function of this upstream sequence of ge gene, we transfected pgep-b-cat ...200212086144
continuous porcine cell lines developed from alveolar macrophages: partial characterization and virus susceptibility.porcine monomyeloid cell lines were established following transfection of primary porcine alveolar macrophage cultures with plasmid psv3neo, carrying genes for neomycin resistance and sv40 large t antigen. the parental clone 3d4 exhibited a relatively rapid doubling time (25.5 h), high plating efficiency and mixed phenotype with respect to growth on a solid support. single cell cloning of the 3d4 parent resulted in establishment of several cell lines; three of them designated 3d4/2, 3d4/21 and 3 ...200212088830
early platelet aggregation as a cause of thrombocytopenia in classical swine fever.twenty pigs were inoculated with a virulent classical swine fever virus isolate to determine the mechanism responsible for thrombocytopenia using histopathologic, ultrastructural, and immunohistochemical (detection of viral antigens gp55 and fviii-rag) techniques. in animals euthanatized at 2, 4, and 6 days postinoculation (dpi), clusters of granular material staining positive for fviii-rag were observed in splenic cords, the marginal zone, hepatic sinusoids, and the perisinusoidal space. moreov ...200212102222
plaque assay for african swine fever virus on swine macrophages.a plaque assay developed to detect the infection of african swine fever virus on swine macrophages is described. plaques were generated by all of the virus isolates tested. the method is suitable not only for virus titration but also for the selection of clones in protocols for isolation/purification of recombinant viruses.200212111419
prevalence of antibodies to classical swine fever, aujeszky's disease, porcine reproductive and respiratory syndrome, and bovine viral diarrhoea viruses in wild boars in croatia.during the hunting season in february 1999, a total of 44 blood samples were collected from wild boars shot in the area of moslavacka gora. these blood samples were examined by enzyme immunoassay for the presence of antibodies to classical swine fever (csfv), aujeszky's disease (adv), bovine viral diarrhoea (bvdv), and porcine reproductive and respiratory syndrome (prrsv) viruses. out of 44 serum samples examined, 17 (38.63%) were positive for csfv, 24 (54.54%) were positive for adv and two (4.5 ...200212121047
pig chromosome aberrations after vaccination against classical swine fever in field trials.chromosomal aberrations were observed after vaccination against classical swine fever (csf) in a previous study done on experimental pigs. to determine if the same effect occurs in farm animals, field trials were done with immunized pigs. the cytogenetic analysis was made from lymphocyte cultures of pigs sampled in three farms of río cuarto region on six different periods: one, pre-vaccination (control) and in five post-vaccination (days 3, 7, 10, 15 and 22). vaccine inoculation induced signific ...200212126897
influence of maternal antibodies on efficacy of a subunit vaccine: transmission of classical swine fever virus between pigs vaccinated at 2 weeks of age.this study shows the effectiveness of vaccination with an e2 subunit vaccine against classical swine fever (csf) in 2-week-old piglets. half of the piglets were carrying maternally derived antibodies (mdas) at the time of vaccination. three and 6 months later, antibody levels were compared between the two treatments. moreover, reduction of virus transmission was investigated at 3 and 6 months by doing transmission experiments. the vaccine was found to be capable of reducing virus transmission si ...200212126914
development of an internal control for the detection of the african swine fever virus by pcr.for the detection of african swine fever virus (asfv) by polymerase chain reaction (pcr) in clinical samples, an internal control was constructed to identify false negative results in each reaction. the internal control was designed in such a way that the same primer pair was used to amplify the internal control and the target dna which were differentiated by size. the lower detection limit was reached at about 30 internal control dna copies and about 50 genomic asfv dna copies. the use of the i ...200212144776
[study on the expression of e2 gene of classical swine fever virus in pichia pastoris and the immunological activity of its expression product].e2 gene of classical swine fever virus (csfv) was cloned into secretory ppic9k pichia pastoris expression vector. after being linearized by digestion, the vector was transformed into pichia pastoris by electroporation to integrate with the genome, the transformants with high copies were screened by g418 and were induced to express with methonal. the results of sds-page and western blot demonstrated that the supernatant of the induced p. pastoris culture contained protein e2. the results of the s ...200212148285
[vaccination of weaner pigs against classical swine fever with the subunit vaccine "porcilis pesti": influence of different immunization plans on excretion and transmission of challenge virus].excretion and transmission of csfv after vaccination with the csf subunit marker vaccine "porcilis pesti" have been studied using the following different vaccination schedules: group a--two vaccinations with an interval of 28 d, challenge 14 d after second vaccination (p.v2.); group b--two vaccinations with an interval of 14 d, challenge 14 d later; group c--two vaccinations with an interval of 28 d, challenge at time of booster vaccination; group d--two vaccinations with an interval of 14 d, ch ...200212174723
arrest of metaphyseal ossification in pigs with experimental classical swine fever. 200212180661
[association between ns5a gene sequence and response to interferon therapy in chronic hepatitis c patients in shanghai].to elucidate relationship between amino acid sequence of non-structural protein 5a (ns5a) and outcome of hcv (1 b) patients after interferon (ifna) therapy.200212196819
structure-based combinatorial protein engineering (scope).presented here is the development a semi-rational protein engineering approach that uses information from protein structure coupled with established dna manipulation techniques to design and create multiple crossover libraries from non-homologous genes. the utility of structure-based combinatorial protein engineering (scope) was demonstrated by its application to two distantly related members of the x-family of dna polymerases: rat dna polymerase beta (pol beta) and african swine fever virus dna ...200212206782
the african swine fever virus protein j4r binds to the alpha chain of nascent polypeptide-associated complex.the african swine fever virus (asfv) j4r protein is expressed late during the virus replication cycle and is present in both the nucleus and the cytoplasm of infected cells. by using the yeast two-hybrid system, direct binding, and coprecipitation from cells, we showed that the j4r protein binds to the alpha chain of nascent polypeptide-associated complex (alpha nac). confocal microscopy indicated that a proportion of j4r and alpha nac interact in areas close to the plasma membrane, as well as t ...200212208975
classical swine fever virus ns5b-gfp fusion protein possesses an rna-dependent rna polymerase activity.rna-dependent rna polymerase (rdrp) is the replicase of positive-strand rna viruses. expression and characterization of the replicase are the first steps in the elucidation of the virus replication mechanism. we expressed nonstructural protein 5b (ns5b) of classical swine fever virus (csfv) as a fusion protein with green fluorescent protein (gfp) in porcine kidney cells (pk-15 cells), natural host cells of csfv. the expressed csfv ns5b-gfp fusion protein possessed rdrp activity. by fluorescence ...200212209316
a new method based on entropy theory for genomic sequence analysis.we have refined entropy theory to explore the meaning of the increasing sequence data on nucleic acids and proteins more conveniently. the concept of selection constraint was not introduced, only the analyzed sequences themselves were considered. the refined theory serves as a basis for deriving a method to analyze non-coding regions (ncrs) as well as coding regions. positions with maximal entropy might play the most important role in genome functions as opposed to positions with minimal entropy ...200212211329
antibodies to selected viral and bacterial pathogens in european wild boars from southcentral spain.serum samples from 78 european wild boars (sus scrofa) harvested during the 1999-2000 hunting season were tested for antibodies to brucella spp., classical swine fever virus, erysipelothrix rhusiopathiae, haemophilus parasuis, leptospira interrogans serovar pomona, mycoplasma hyopneumoniae, pseudorabies virus (prv), porcine parvovirus (ppv), porcine reproductive and respiratory syndrome virus, salmonella serogroups b, c, and d, streptococcus suis, and swine influenza virus (siv) serotypes h1n1 a ...200212238391
a structural model of pestivirus e(rns) based on disulfide bond connectivity and homology modeling reveals an extremely rare vicinal disulfide.e(rns) is a pestivirus envelope glycoprotein and is the only known viral surface protein with rnase activity. e(rns) is a disulfide-linked homodimer of 100 kda; it is found on the surface of pestivirus-infected cells and is secreted into the medium. in this study, the disulfide arrangement of the nine cysteines present in the mature dimer was established by analysis of the proteolytically cleaved protein. fragments were obtained after digestion with multiple proteolytic enzymes and subsequently ...200212239315
synthetic peptide-based immunoassay as a supplemental test for hcv infection.hepatitis c virus (hcv) is a single strand rna hepatotrophic virus infecting 170 millions around the world and 20% of egyptian blood donors. although there has been significant improvement in the enzyme immunoassays (eias) in population screening of hcv infection, the development of a low variability, easy to automate and inexpensive supplemental test to support the current immunoassays was of a major concern to several laboratories.200212367764
recombinant hepatitis c virus-like particles expressed by baculovirus: utility in cell-binding and antibody detection assays.hepatitis c virus (hcv) is difficult to study due to the lack of an efficient cell culture system or small animal model. as a result, hcv-cell interactions are not well-defined. in addition, several studies have identified a subset of patients in whom hcv rna is present, but hcv antibody is not detected. we produced recombinant baculoviruses that expressed hcv structural proteins (core, e1 and e2, nt 342-2651) or control proteins. the hcv structural protein precursor was processed into immunorea ...200212376962
localization of classical swine fever virus in male gonads during subclinical infection.in an experiment using ten boars, the distribution of classical swine fever virus (csfv) was determined in the male reproductive tract by in situ hybridization over a period of 120 days after intranasal inoculation. csfv was detected in the testicular tissue of infected boars. viral nucleic acid was localized to spermatogonia, spermatocytes and spermatids but was not detected in the epithelia of the prostate, epididymis or bulbourethral gland. sections from control, csfv-negative, pigs showed no ...200212388807
a phylogenetic-tree analysis elucidating nosocomial transmission of hepatitis c virus in a haemodialysis unit.nosocomial transmission of hepatitis c virus (hcv) subtype 1b involving 11 haemodialysis patients occurred in a haemodialysis unit in japan in march 2000. sequencing of the hcv-e1 region (411-bp) and phylogenetic-tree analysis showed near identity between hcv isolates derived from these patients and a haemodialysis patient who was known to be hcv-positive. the mode of transmission could not be conclusively established, but retrospective analysis suggested that the sharing of contaminated multido ...200212431208
african swine fever virus polyproteins pp220 and pp62 assemble into the core shell.african swine fever virus (asfv), a complex enveloped dna virus, expresses two polyprotein precursors, pp220 and pp62, which after proteolytic processing give rise to several major components of the virus particle. we have analyzed the structural role of polyprotein pp62, the precursor form of mature products p35 and p15, in virus morphogenesis. densitometric analysis of one- and two-dimensional gels of purified virions showed that proteins p35 and p15, as well as the pp220-derived products, are ...200212438573
apoptosis of thymocytes related to cytokine expression in experimental classical swine fever.atrophy of the thymic cortex and loss of thymocytes were studied in 32 pigs inoculated with the virulent strain "alfort" of classical swine fever (csf) virus and killed at intervals from 2 to 15 days after infection. immunohistochemical, ultrastructural, elisa and tunel methods were used. the results suggested that direct action of csf virus on thymocytes played no more than a minor role. the massive lymphoid depletion observed in the thymus, may, however, have been associated with the numerical ...200212443731
lipopolysaccharide-induced impairment of classical swine fever virus infection in monocytic cells is sensitive to 2-aminopurine.lipopolysaccharide (lps) impairs classical swine fever virus (csfv) replication in monocytic cells, which are primary targets for csfv and mediators of virus-induced immunomodulation. although soluble antiviral factors including interferons (ifn) were not detected, ifn-alpha and ifn-beta mrna were induced. the serine threonine protein kinase inhibitor 2-aminopurine, impeded this antiviral activity. these results indicate that the lps-induced antiviral state employs signaling pathways, in which t ...200211684317
steatosis and liver cancer in transgenic mice expressing the structural and nonstructural proteins of hepatitis c virus.the aim of this study was to determine whether expression of hepatitis c virus proteins alters hepatic morphology or function in the absence of inflammation.200211832450
identification of t-cell epitopes in the structural and non-structural proteins of classical swine fever virus.to identify new t-cell epitopes of classical swine fever virus (csfv), 573 overlapping, synthetic pentadecapeptides spanning 82% of the csfv (strain glentorf) genome sequence were synthesized and screened. in proliferation assays, 26 peptides distributed throughout the csfv viral protein sequences were able to induce specific t-cell responses in pbmcs from a csfv-glentorf-infected d/d haplotype pig. of these 26 peptides, 18 were also recognized by pbmcs from a csfv-alfort/187-infected d/d haplot ...200211842250
epidemiology and control of an outbreak of classical swine fever in wild boar in switzerland.an outbreak of classical swine fever in wild boar in the southern part of switzerland (canton of ticino) was investigated after the implementation of control measures in a defined infected area (the risk zone), and in a surrounding surveillance zone (the non-risk zone). after the disease had been detected, hunting was not allowed in the risk zone for over six months, during which the disease was left to run its course, but hunting was continued in the non-risk zone for one month. after seven mon ...200211842816
method for detection of extraneous active bovine viral diarrhoea virus and classical swine fever virus in animal viral vaccines by rt-pcr, which amplify negative-strand viral rna in infected cells.an oligonucleotide sense primer, pst324alpha, was designed and used for synthesizing cdna from negative-strand viral rna in infected cells and used for rapid detection of active extraneous bovine viral diarrhoea virus (bvdv) and classical swine fever virus (csfv) in animal viral vaccines by culturing a sample in cells followed by reverse transcriptase-polymerase chain reaction (rt-pcr). active and inactivated viruses of bvdv no. 12-43 strain and csfv gpe(-)strain were inoculated to bovine testic ...200211846427
quantitative assessment of clinical signs for the detection of classical swine fever outbreaks during an epidemic.the performance of clinical signs as a diagnostic test for the detection of classical swine fever (csf) outbreaks during the 1997-1998 csf epidemic in the netherlands was evaluated by constructing and analysing a receiver operating characteristic (roc) curve. this curve assesses the discriminating ability of a diagnostic test over a range of test signals. the cut-off values for a defined diagnostic test to detect csf outbreaks were set by different combinations of clinical signs observed. the ar ...200211856582
experimental non-transmissible marker vaccines for classical swine fever (csf) by trans-complementation of e(rns) or e2 of csfv.three mutants with deletions in the e2 gene of the infectious dna copy of the classical swine fever virus (csfv) strain-c were constructed: one missing the b/c domain of csfv-e2 between amino acids (aa) 693 and 746, one missing the a domain between aa 800 and 864, and one missing the complete e2 between aa 689 and 1062. all three csfv-e2 deletion mutants were unable to generate viable virus, indicating that each of the antigenic domains of e2 is essential for viability of csfv. to rescue the csf ...200211858861
repression of african swine fever virus polyprotein pp220-encoding gene leads to the assembly of icosahedral core-less particles.african swine fever virus (asfv) polyprotein pp220, encoded by the cp2475l gene, is an n-myristoylated precursor polypeptide that, after proteolytic processing, gives rise to the major structural proteins p150, p37, p34, and p14. these proteins localize at the core shell, a matrix-like virus domain placed between the dna-containing nucleoid and the inner envelope. in this study, we have examined the role of polyprotein pp220 in virus morphogenesis by means of an asfv recombinant, v220i, containi ...200211861832
[prediction of recognition sites for genomic replication of classical swine fever virus with information analysis].in order to explore the mechanism for the genomic replication of classical swine fever virus (csfv), so as to make a basis for investigating its pathogenicity, an introduction of the information theory is presented in connection with the statistical mechanics, whence small-sample statistics appears naturally as a consequence of the bayesian approach. furthermore, a selection rule for identifying the pattern of a recognition site for an rna-binding protein is proposed by means of the maximum entr ...200211862713
sequences and replication of genomes of the archaeal rudiviruses sirv1 and sirv2: relationships to the archaeal lipothrixvirus sifv and some eukaryal viruses.the double-stranded dna genomes of the viruses sirv1 and sirv2, which infect the extremely thermophilic archaeon sulfolobus and belong to the family rudiviridae, were sequenced. they are linear, covalently closed at the ends, and 32,312 and 35,502 bp long, respectively, with an a+t content of 75%. the genomes of sirv1 and sirv2 carry inverted terminal repeats of 2029 and 1628 bp, respectively, which contain multiple direct repeats. sirv1 and sirv2 genomes contain 45 and 54 orfs, respectively, of ...200111878892
genetic typing of ruminant pestivirus strains from northern ireland and the republic of ireland.a study was performed to investigate the genotypes and sub-groups of pestiviruses present in ruminants in ireland. these comprised one ovine and eighteen bovine pestiviruses from northern ireland and six bovine pestiviruses from the republic of ireland. a 288 base pair (bp) portion of the 5'-non coding region (5'-ncr) from each of 25 pestiviruses collected over a period of 31 years was amplified by reverse-transcription-polymerase chain reaction (rt-pcr) and the product directly sequenced. from ...200111883891
rna triphosphatase component of the mrna capping apparatus of paramecium bursaria chlorella virus 1.paramecium bursaria chlorella virus 1 (pbcv-1) elicits a lytic infection of its unicellular green alga host. the 330-kbp viral genome has been sequenced, yet little is known about how viral mrnas are synthesized and processed. pbcv-1 encodes its own mrna guanylyltransferase, which catalyzes the addition of gmp to the 5' diphosphate end of rna to form a gpppn cap structure. here we report that pbcv-1 encodes a separate rna triphosphatase (rtp) that catalyzes the initial step in cap synthesis: hyd ...200111160672
chimeric (marker) c-strain viruses induce clinical protection against virulent classical swine fever virus (csfv) and reduce transmission of csfv between vaccinated pigs.two live recombinant vaccines (flc9 and flc11) against classical swine fever (csf) were evaluated for their capacity to reduce transmission of virulent csf virus (csfv) among vaccinated pigs. in flc9 the 5' terminal half of the e2 gene of the c-strain, a csfv vaccine strain, was exchanged with the homologous gene of the bovine viral diarrhoea virus (bvdv) strain 5250, the e(rns) gene was exchanged likewise in the chimeric flc11 virus. both recombinant vaccines induce an antibody response in pigs ...200111163670
dna-mediated protection against classical swine fever virus.four eukaryotic expression plasmids containing the entire e2 gene sequence of classical swine fever virus (csfv) were constructed: (a) pcdst, with 5' signal and 3' transmembrane sequences; (b) pcdsw, with 5' signal sequence only; (c) pcdwt, with transmembrane sequences only; and (d) pcdww, containing the e2 gene alone. all four plasmids were readily transfected into bhk-21 cells, with pcdst and pcdsw resulting in secretion of e2 antigen. the latter two plasmids were also shown to induce a humora ...200111163677
development of a competitive elisa using a truncated e2 recombinant protein as antigen for detection of antibodies to classical swine fever virus.the sequence encoding a truncated e2 glycoprotein of the alfort/187 strain of classical swine fever virus (csfv) was expressed in escherichia coli using the pet expression system and the recombinant product purified by ni-nta agarose affinity chromatography. the antigenicity of this recombinant protein was demonstrated by immunoblot using anti- csfv-specific antibodies. a monoclonal antibody was produced against the truncated e2 protein and used as competitor in an elisa for the detection of ant ...200111170845
the non-haemadsorbing african swine fever virus isolate asfv/nh/p68 provides a model for defining the protective anti-virus immune response.african swine fever virus asfv/nh/p68 is a naturally occurring, non-haemadsorbing and non-fatal isolate. longitudinal clinical and immunological studies on 31 pigs inoculated oronasally or intramuscularly with this isolate defined two discrete groups of animals: those developing asf chronic type lesions and those remaining asymptomatic. animals developing lesions had viraemia and fever late after infection, nk activity levels close to that of control animals and high levels of anti-asfv specific ...200111172092
depletion of cd4(+) and cd8(high+) t-cells before the onset of viraemia during classical swine fever.leukopenia, in particular lymphopenia, is a characteristic early event during classical swine fever (csf). this was the case in both highly virulent (csf virus (csfv) strain brescia) and moderately virulent (csfv uelzen) infections. the leukopenia involved leukocyte sub-populations in a disparate manner, with b-lymphocytes, helper t-cells and cytotoxic t-cells being the most affected. depletion of lymphocyte sub-populations occurred 1-4 days before virus could be detected by rt-pcr in the serum. ...200111182144
duration of the protection of an e2 subunit marker vaccine against classical swine fever after a single vaccination.the period during which pigs are protected after vaccination is important for the successful usage of a marker vaccine against classical swine fever virus (csfv) in an eradication programme. in four animal experiments with different vaccination-challenge intervals we determined the duration of protection of an e2 subunit marker vaccine in pigs after a single vaccination. unvaccinated pigs were included in each group to detect transmission of the challenge virus. three groups of six pigs were vac ...200111182497
solution structure of a viral dna repair polymerase.dna polymerase x (pol x) from the african swine fever virus (asfv) specifically binds intermediates in the single-nucleotide base-excision repair process, an activity indicative of repair function. in addition, pol x catalyzes dna polymerization with low nucleotide-insertion fidelity. the structural mechanisms by which dna polymerases confer high or low fidelity in dna polymerization remain to be elucidated. the three-dimensional structure of pol x has been determined. unlike other dna polymeras ...200111685238
solution structure of a viral dna polymerase x and evidence for a mutagenic function.the african swine fever virus dna polymerase x (asfv pol x or pol x), the smallest known nucleotide polymerase, has recently been reported to be an extremely low fidelity polymerase that may be involved in strategic mutagenesis of the viral genome. here we report the solution structure of pol x. the structure, unique within the realm of nucleotide polymerases, consists of only palm and fingers subdomains. despite the absence of a thumb subdomain, which is important for dna binding in other polym ...200111685239
epitope mapping and affinity purification of monospecific antibodies by escherichia coli cell surface display of gene-derived random peptide libraries.we report a method for the precise mapping of linear epitopes by presenting a peptide library on the surface of escherichia coli cells. a random library of gene fragments derived from the classical swine fever virus (csfv) envelope protein e(rns) was generated by dnase i cleavage and cloned into a specially designed bacterial surface display vector. a carboxyterminally truncated intimin, an adhesin from enteropathogenic e. coli, serves as a carrier protein to present foreign peptides on the surf ...200111687250
the trans golgi network is lost from cells infected with african swine fever virus.the cellular secretory pathway is important during the assembly and envelopment of viruses and also controls the transport of host proteins, such as cytokines and major histocompatibility proteins, that function during the elimination of viruses by the immune system. african swine fever virus (asfv) encodes at least 26 proteins with stretches of hydrophobic amino acids suggesting entry into the secretory pathway (r. j. yanez, j. m. rodriguez, m. l. nogal, l. yuste, c. enriquez, j. f. rodriguez, ...200111689656
antigenic and immunogenic properties of a chimera of two immunodominant african swine fever virus proteins.a chimera of the two immunodominant african swine fever (asf) virus proteins p54 and p30 was constructed by insertion of the gene cp204l into a not i restriction site of e183l gene. the resulting chimeric protein p54/30, expressed by a recombinant baculovirus in insect cells and in trichoplusia ni larvae, retained antigenic determinants present in both proteins and reacted in western blot with a collection of sera from inapparent asf virus carrier pigs. remarkably, pigs immunized with the chimer ...200111699955
oral and sub-cutaneous vaccination of commercial pigs with a recombinant porcine adenovirus expressing the classical swine fever virus gp55 gene.a recombinant porcine adenovirus expressing the classical swine fever virus (csfv) gp55/e2 gene was administered to commercially available pigs via oral or subcutaneous routes and their susceptibility to oral and subcutaneous challenge with csfv was determined. 100% of animals vaccinated and challenged subcutaneously were protected. in the groups of pigs vaccinated either orally or subcutaneously and then challenged orally, 60% of animals were protected. before challenge, neutralising antibodies ...200111699963
adsorption of colostral antibodies against classical swine fever, persistence of maternal antibodies, and effect on response to vaccination in baby pigs.to determine kinetics of antibody absorption, persistence of antibody concentrations, and influence of titers on vaccination of baby pigs with a vaccine against classical swine fever (csf).200111703028
an experimental infection with classical swine fever virus in pregnant sows: transmission of the virus, course of the disease, antibody response and effect on gestation.an experimental infection with classical swine fever (csf) virus in 12 conventional gilts, housed in a sow-box housing system, was conducted in order to evaluate horizontal transmission, clinical, virological and serological response, and the effect on gestation. two of the 12 gilts, of which 10 were pregnant, were experimentally inoculated. they became viraemic for the first time 6 days post-inoculation (dpi). the contact gilts became viraemic between 18 and 21 days post inoculation. on the bas ...200111708677
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