Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| identification of pseudorabies virus-exposed swine with a gi glycoprotein enzyme-linked immunosorbent assay. | a monoclonal antibody specific for the gi glycoprotein of virulent pseudorabies virus was produced and used to affinity purify gi glycoprotein. the purified gi was used in an enzyme-linked immunosorbent assay (elisa) that identified and differentiated field virus-exposed animals from animals vaccinated with gi-deleted virus. the gi elisa was evaluated by comparing it with the virus neutralization test and with a standard elisa which does not distinguish between vaccinated and naturally infected ... | 1989 | 2555390 |
| general characteristics and viral susceptibility of a newborn pig kidney (npk) continuous culture. | we have developed a fibroblastic-like continuous culture of newborn pig kidney (npk). the current cell line was serially passaged 160 times and appeared to be well suited for production and assay of a number of viruses affecting pigs, such as pig parvovirus, pseudorabies and transmissible gastroenteritis. the cell line appeared aneuploid, with a modal chromosome number of 36 and induced tumors, classified as fibrosarcoma, in athymic mice. | 1989 | 2555655 |
| serologic status of pseudorabies virus in growing-finishing pigs in quarantined herds. | it has been reported that pseudorabies virus (prv) stops spreading within growing-finishing sections of a large percentage of infected farrow-to-finish herds. this study was designed to follow the prv status of growing-finishing pigs in a sample of infected herds. fifteen infected herds were selected, of which 11 had seropositive finishing pigs and 4 had seronegative finishing pigs. these herds were visited quarterly for one year, and a cross section of growing-finishing pigs was tested for the ... | 1989 | 2557311 |
| identification of pseudorabies virus-infected swine herds by evaluating the serostatus of boars or finishing pigs. | data were collected from 39 minnesota swine farms quarantined for pseudorabies virus (prv) infection. each herd was serologically evaluated for antibodies to prv in the sows, boars, and finishing pigs. to identify prv-seropositive swine herds, the kappa statistic was used to estimate the effectiveness of evaluating the prv serostatus of boars or of finishing pigs. using the serostatus of all herd boars, the sensitivity (with 95% confidence interval) of identifying prv-infected herds was 58 +/- 2 ... | 1989 | 2557313 |
| an improved hemagglutination-inhibition test for pseudorabies virus. | 1989 | 2557479 | |
| [use of the tetrazolium salt reduction test in the detection of phagocytic activity in pigs]. | one of the indicators of non-specific, cell-mediated immunity can be the ability of phagocytic system to react to the presence of antigenic impulses and stimulators. the phagocytic activity induced in this way in vitro can be evaluated quantitatively by help of different methods. in this study the method of the reduction of colourless tetrazolium salt (int) to the red formazane was used. the optimum conditions for carrying out this test in isolated peripheral pig leucocytes were determined. it w ... | 1989 | 2734992 |
| comparative pathogenesis of three strains of pseudorabies virus in pigs. | three strains of pseudorabies virus were intranasally inoculated into 10-week-old pigs and the pathogenesis of the infection was compared. virulent nia-3 virus caused widespread necrotic lesions in nasal mucosa, rapidly invading the stroma and infecting axons of olfactory nerves within 24 h of inoculation. intermediate virulent virus 2.4n3a, a mutant strain derived from nia-3, caused less necrosis of the mucosa and did not reach axons of olfactory nerves until 72 h after inoculation. bartha viru ... | 1989 | 2560112 |
| immunological surveillance in a pseudorabies quarantined herd using gilts and their progeny as sentinels. | specific pathogen free gilts and their progeny were evaluated to use as sentinels in a pseudorabies virus (prv) infected herd by immunologically monitoring for prv seroconversions. time intervals targeted were pre- and post-prv vaccinations, herd exposure, and farrowing to finishing. post-prv vaccinations, gilts showed low prv lymphocyte stimulation and humoral responses. following herd exposure, control gilts prv seroconverted and prv vaccinated gilts increased (2 to 4 times) in virus neutraliz ... | 1989 | 2560914 |
| the effect of human recombinant interleukin-2 on the porcine immune response to a pseudorabies virus subunit vaccine. | the effect of human recombinant interleukin-2 (ril-2) as an immune enhancing agent was evaluated in pigs vaccinated with a pseudorabies virus subunit vaccine (sv). two groups of three pigs received two 25 micrograms doses of sv given 3 weeks apart. one group received 10(5) kg-1 day-1 of ril-2 subcutaneously over two 5-day periods beginning on the day of the first and second vaccine inoculation. six other pigs were immunized with two 5 micrograms doses of sv. three of these pigs were treated as a ... | 1989 | 2626820 |
| appearance of interferon-alpha in serum and signs of reduced immune function in pigs after transport and installation in a fattening farm. | pigs were transported from several breeding facilities at the age of 10-12 weeks and regrouped in a fattening farm, specialized in breeding pigs for subsequent slaughter. blood samples were obtained from the animals just before transport and daily for 17 days after installation in the fattening farm. on each occasion a group of ten animals (170 animals in total) was sampled. the levels of interferon-alpha (ifn-alpha) in serum were measured as antiviral activity in a cytopathic effect inhibition ... | 1989 | 2629198 |
| interactions of pseudorabies virus with swine alveolar macrophages: effects of virus infection on cell functions. | in order to assess the effect of pseudorabies virus (prv) infection on the function of swine alveolar macrophages (am), lung lavage cells were cultured, infected with one of six strains of prv, and various activities were measured. activity measurement included viability, phagocytosis of yeast, phagosome-lysosome fusion, phagocytosis of opsonized particles, and superoxide release. am were infected with 5 x 10(-3) pfu/cell, and the comparative assessment of functions was performed at 18-20 h post ... | 1989 | 2708911 |
| monoclonal blocking elisa detecting serum antibodies to the glycoprotein gii of aujeszky's disease virus. | a monoclonal blocking enzyme-linked immunosorbent assay (elisa) for detection of antibodies to aujeszky's disease virus (adv) in porcine serum was developed. this elisa is based on the reaction between virus antigen immobilized in a microdilution plate and a monoclonal antibody (mab) reactive with a highly stable epitope on a glycoprotein complex, gii, of adv. the viral epitope was expressed by 18 european field, laboratory and vaccine strains of adv. the mab used in the test was selected among ... | 1989 | 2547813 |
| inhibition of tyrosine protein kinases by the antineoplastic agent adriamycin. | adriamycin, a lipid-interacting anti-cancer agent, was found to inhibit the phosphorylation of polyglu/tyr (4:1) by tyrosine protein kinases either from spleen or expressed by the oncogene of abelson murine leukemia virus. the dose dependent inhibition by adriamycin is accounted for by competition for the atp binding site, but it is also deeply influenced by the nature and concentration of the phosphorylatable substrate, suggesting multiple interactions with the enzyme. the phosphorylation at ty ... | 1989 | 2543396 |
| recombinant-derived modified-live herpesvirus vaccines. | 1989 | 2558526 | |
| immunohistologic study of pulmonary and lymphatic tissues from gnotobiotic pigs inoculated with ara-t-resistant strain of pseudorabies virus. | ara-t-resistant strain of pseudorabies virus (prv) was inoculated intranasally into six 2-week-old gnotobiotic pigs. five inoculated pigs were sneezing and coughing. in pigs 1 to 4 killed on postinoculation days (pid) 3, 5, 7, and 9, respectively, prv antigen was detected in respiratory epithelial cells, and pigs had severe pneumonitis. in pigs 5 and 6 killed on pid 11 and 13, respectively, prv antigen was localized in macrophages in alveoli and necrotizing nodules. immunoglobulin-containing cel ... | 1989 | 2559633 |
| aujeszky's disease. | 1989 | 2559694 | |
| sites of virus replication in the genital organs of boars inoculated in the cavum vaginale with pseudorabies virus. | to determine the sites of replication and the evolution of pseudorabies virus infection in boar genital organs, 5 belgian landrace boars were inoculated with pseudorabies virus unilaterally in the cavum vaginale of the testis. virus replication took place only in cells of the tunica vaginalis of both cava vaginalia. infection of the serosa led to exudative periorchitis and increased scrotal fluid, resulting in a severely swollen scrotal region. these experimental findings were similar to finding ... | 1989 | 2539030 |
| specific antibody against the aujeszky's disease virus in the complex cumulus oophorus-oocyte of sows. | oocytes collected from sows vaccinated and revaccinated with an inactivated vaccine against aujeszky's disease (ad) were examined for the presence of specific antibodies of the igg class against ad virus in the complex cumulus oophorus-oocyte by means of immunocytochemical methods. no specific antibody of the igg class was detected in the cumulus-oocyte complexes collected from sows before vaccination. on the other hand, the specific igg antibody was found in all immunocytochemically examined co ... | 1989 | 2540605 |
| horizontal transmission of aujeszky's disease virus from sheep to pigs. | eight 2-month-old merino lambs were inoculated intranasally with different (10(2.0)-10(5.0)tcid50) amounts of aujeszky's disease virus (adv). electron microscopic studies indicated that adv replicated in extra-neural sites, in the epithelial cells of the mucosa of the upper and lower respiratory tract. although the virus was excreted continuously in nasal discharges, horizontal transmission to contact lambs failed. the surviving exposed and contact lambs had no demonstrable antibodies against ad ... | 1989 | 2541533 |
| antibody response of pseudorabies virus subunit-vaccinated pigs to viral nucleocapsid proteins following low-dose virus challenge of immunity. | the antibody response to pseudorabies virus nucleocapsid proteins (ncp) was evaluated by the western immunoblot analysis before and after challenge of immunity by nasal inoculation of 10(2.3) plaque-forming units of virus in 10 pigs that had been vaccinated with pseudorabies virus envelope glycoproteins. antibody to 5 ncp with molecular mass of 140, 63, 41, 34, and 23 kd was first detected in vaccinated and nonvaccinated pigs on day 14 after challenge of immunity. antibody to 2 of the 5 ncp cont ... | 1989 | 2551199 |
| influence of isoprinosine on lymphocyte function in virus-infected feeder pigs. | pseudorabies is a porcine herpesvirus of major importance in the swine industry. isoprinosine is an immunomodulating drug that has been shown to be beneficial in treating herpesvirus infections. twenty-four 7-week-old pigs were allotted within litters to 1 of 4 groups: control, isoprinosine (iso), pseudorabies virus (prv), or isoprinosine and pseudorabies virus (iso-prv). isoprinosine was administered daily for 16 days to the iso and iso-prv groups (75 mg/kg of body weight/day, po). immunity in ... | 1989 | 2478051 |
| neuropathogenesis of pseudorabies: leakage of anti-viral antibody and serum constituents into cerebrospinal fluid of infected pigs. | antibody levels to pseudorabies virus (prv) in cerebrospinal fluid (csf) were compared to serum levels from immunized and infected pigs. antibody was measured by single-dilution indirect solid-phase radioimmunoassay (iria). there was significantly higher csf anti-prv igg relative to serum anti-prv igg (anti-prv index, %) from infected pigs (1.390%, n = 14) than from vaccinated ones (0.141-0.149%, n = 5 and 7). the index from vaccinated and challenged pigs was intermediate (0.627%, n = 16), sugge ... | 1989 | 2535701 |
| in vitro comparison between four variants of aujeszky's disease virus. | four aujeszky's disease (pseudorabies) virus variants were characterized in vitro by investigation of their resistance to heat at 48 degrees c, sensitivity to trypsin and ability to replicate in pig alveolar macrophages, two of these variants (ls-1 and ls-2) were cloned previously from a single isolate of virus and showed differing pathogenicity for pigs; the virulent stanley strain; and the non-virulent nia-4 strain were included for comparison. heat treatment produced slight decreases in infec ... | 1989 | 2555108 |
| the potency testing of pseudorabies vaccines in pigs. a proposal for a quantitative criterion and a minimum requirement. | a criterion for the potency testing of pseudorabies vaccine based on the difference between the mean weight gain during the seven days after pathogenic challenge of vaccinated or control piglets is proposed. this criterion, termed delta g7, has been studied as a function of initial weight variation of the animals, different challenge strains and the period between challenge and the end of the test. the statistical analysis of results optimizes the experimental parameters and gives rise to a quan ... | 1989 | 2537829 |
| interactions of pseudorabies virus with swine alveolar macrophages i: virus replication. | the replication of pseudorabies virus (prv) in cultured swine alveolar macrophages (am) was studied using 6 different virus strains. am were highly permissive to prv infection, with progeny virus titres of 10(7) tcid50/ml from some strains. virus progeny titres were higher in cultures infected with the field strains s-62 and 4892 than in cultures infected with the strains bartha or prv-c. virus replication, viral dna synthesis and the concomitant cell damage were dependent upon virus input m.o.i ... | 1989 | 2538108 |
| rapid diagnosis of aujeszky's disease in pigs by improved in situ hybridization using biotinylated probes on paraffin-embedded tissue sections. | a practical in situ hybridization (ish) method has been developed for the rapid diagnosis of pseudorabies virus (prv) infection in pigs. the method utilizes routine formalin fixed and paraffin-embedded tissue sections, non radioactive biotin-labelling, simple hybridization procedure and diaminobenzidine (dab) silver enhancement detection system. the rapid (ish) method showed concordance with the direct filter hybridization (dfh) and with the peroxidase-antiperoxidase (pap) assays. by the simplif ... | 1989 | 2538976 |
| development of an elisa to differentiate between animals either vaccinated with or infected by aujeszky's disease virus. | the use of two monoclonal antibodies specific for glycoproteins gi and giii of the pseudorabies virus led to the development of a competitive elisa which made it possible to differentiate animals infected with pseudorabies virus from animals vaccinated with the strains of the virus bartha, nai4 or norden. a postvaccinal serological response could be detected from three to four weeks after vaccination. after the virulent challenge of these vaccinated pigs an infectious serological response became ... | 1989 | 2538951 |
| aujeszky's disease elisa: cross-reactions with other herpesvirus antisera. | the production of antibodies in pigs to 11 herpesviruses was investigated in relation to their ability to cross-react with aujeszky's disease virus (suid herpesvirus 1--shv1). of the herpesviruses tested only two, sheep herpesvirus (caprine herpesvirus 1) and dog herpesvirus (canid herpesvirus 1), failed to produce homologous virus antibodies. only the antibodies to bovine herpesvirus 1 (bhv1) produced a cross-reaction by shv1 enzyme-linked immunosorbent assay (elisa). no shv1 neutralizing antib ... | 1989 | 2548320 |
| erratum. | the article by marjorie sun "virginia oks rabies vaccine test" (news & comment, 14 july, p. 126) states that the first outdoor experiment with a genetically engineered virus is expected to be conducted by the boyce thompson institute for plant research at cornell university. the first outdoor test of a genetically modified virus actually took place in 1984, when saul kit of baylor college tested an altered pseudorabies virus on pigs. | 1989 | 17773341 |
| marker vaccines, virus protein-specific antibody assays and the control of aujeszky's disease. | vaccination of pigs is widely practised to control aujeszky's disease (ad). molecular biological research revealed that several conventionally attenuated virus vaccines harbour deletions in their genomes. the deleted genes are nonessential for virus replication and can be involved in the expression of virulence. these findings have prompted several groups to construct well-characterized deletion mutants of ad virus that do not express either glycoprotein gi, gx or giii. these mutants have also b ... | 1990 | 2169682 |
| [epizoologic studies of the detection of antibodies against aujeszky's disease virus in sera and blood eluates of swine from thailand using elisa ("enzygnost," behring), serum neutralization test and "aujeszky latex kit" (iffa merieux)]. | the results of three tests for aujeszky's disease were analysed and compared. the presence of aujeszky's antibodies was determined by "enzyme-linked-immunosorbent-assays" (elisa, "enzygnost"), behring company, marburg; "serum-neutralization-tests" (snt); and "latex agglutination-tests" (lt, "aujeszky-latex-kit"), iffa merieux company, laupheim. whole blood and sera samples were taken from 805 swine from 26 of thailand's provinces. these samples were analysed to determine if eluates of whole bloo ... | 1990 | 2169687 |
| exposure of pigs to a pseudorabies virus formed by in vivo recombination of two vaccine strains in sheep. | 1990 | 1965578 | |
| restriction fragment pattern analysis of genomes from french isolates of suis herpes virus 1 (aujeszky's disease virus). | purified dna from 45 isolates of suis herpes virus 1 (shv1) collected between 1980 and 1987 from clinical outbreaks of aujeszky's disease on french farms was compared by restriction fragment pattern (rfp) analysis. the bamhi generated rfps were found to be distinguishable, confirming rfp analysis as a potential epidemiological tool. the rfp could be assigned to two established major electrophoretic types and different subtypes. the rfp analysis indicated that the majority of outbreaks were cause ... | 1990 | 1974130 |
| evidence of long distance airborne transmission of aujeszky's disease (pseudorabies) virus. | aujeszky's disease has been the subject of an eradication campaign in denmark since 1980. a detailed knowledge of the virus strains present in the country was provided by restriction fragment analyses of older clinical isolates, and of isolates from all the virologically confirmed outbreaks since 1985. the introduction of foreign strains into southern border areas was demonstrated during the winters of 1984/85, 1986/87 and 1987/88. an epizootic during the winter of 1987/88 was shown to correlate ... | 1990 | 1980166 |
| economic analysis of an epizootic of pseudorabies and subsequent production following the institution of a vaccination program in a pennsylvania swine herd. | the economic impact of pseudorabies was examined in a commercial swine herd. at the onset of clinical signs, a modified-live virus vaccine was administered to the sow herd and repeated at 3-month intervals. according to production data from the 320-sow farrow-to-feeder unit, preweaning mortality increased twofold, and subsequently, the number of pigs weaned per litter decreased by 19% (p less than 0.005) during the 5-week epizootic. also, the number of pigs born alive decreased by 6% during the ... | 1990 | 2166725 |
| appearance of slow-reacting, complement-requiring hemagglutination-inhibiting antibody in swine infected with pseudorabies virus. | slow-reacting, complement-requiring hemagglutination-inhibiting (hi) antibody was detected in sera from pigs infected with pseudorabies virus; approximately 16 hemolytic units of complement were necessary for the detection of such antibody. higher hi antibody titers were obtained when antigen and serum were allowed to incubate before addition of complement than when all three components were incubated at the same time. a hi test was developed in which antigen-serum mixtures were incubated at 4 d ... | 1990 | 2167056 |
| vaccination against pseudorabies with glycoprotein gi+ or glycoprotein gi- vaccine. | subunit pseudorabies vaccines that contained only purified glycoproteins of either of 2 strains of pseudorabies virus (prv) were prepared and subsequently tested for safety and efficacy. the strains of virus used for vaccine production differed in at least 2 properties. one strain (kojnok) was virulent for pigs and was believed to code for the entire complement of viral glycoproteins. the other (kaplan) was a deletion mutant that was unable to code for structural viral glycoproteins gi and gp63. ... | 1990 | 2167620 |
| [development of an inactivated vaccine for the protection of cattle against aujeszky's disease]. | the effects of an inactivated strain of aujeszky's disease vaccine in cattle were investigated. it has not been possible to use vaccines licensed for use in pigs successfully in cattle even though cattle develop neutralizing antibodies to these vaccines. the addition of zinc compounds to the vaccines resulted in protection in cattle. the basis for the use of zinc is discussed. a mutant based vaccine was effective following local administration, but was not when administered parenterally. anti-pr ... | 1990 | 2167657 |
| rapid detection of pseudorabies virus genomic sequences in biological samples from infected pigs using polymerase chain reaction dna amplification. | the presence of the pseudorabies virus (prv) genome in infected hosts has previously been studied by standard hybridization techniques, which showed the viral genome to be present at very low levels in infected tissues. the recently introduced polymerase chain reaction (pcr) procedure provides an alternative and rapid means of amplifying small quantities of specific dna sequences. we applied this technique to a study of pigs infected by prv. the sequence selected for amplification consisted of 2 ... | 1990 | 2169679 |
| population biology of pseudorabies in swine. | a deterministic mathematical model of the population biology of pseudorabies in swine was used to clarify some of the basic features of the host-virus relationship and to inquire into the circumstances that promote or impede virus persistence in a single herd. when the basic reproductive rate of the infection (ie, the number of secondary infections resulting from the introduction of a single infective animal into a wholly susceptible herd) is greater than unity, the model suggests that the numbe ... | 1990 | 2154146 |
| [aujeszky's disease: sanitation of swine herds in enzootically infected areas using labelled vaccines]. | both in the federal republic of germany and in some neighbouring countries the epizootic situation of aujeszky's disease has been unsatisfactory for a long time, especially in areas with a high pig density. new findings on vaccines with certain protein deletions have recently indicated the possibility that the disease might be eradicated even in vaccinated herds. by using labelled vaccines it seems possible to distinguish the carriers of vaccine virus antibodies from the carriers of field virus ... | 1990 | 2154177 |
| a field trial to determine the feasibility of delivering oral vaccines to wild swine. | a field study was conducted on ossabaw island, georgia (usa) to determine the feasibility of delivering oral vaccines to wild swine (sus scrofa). baits were made of polymerbound fish meal and contained a gelatin capsule as a potential vaccine chamber. two biomarkers, iophenoxic acid and tetracycline, were incorporated into each bait, and soured chicken mash was used as an attractant. baits (n = 1,980) were distributed in a grid pattern on a 405-ha test site and monitored for animal disturbance. ... | 1990 | 2174467 |
| sero-epidemiological screening of pig sera collected at the slaughterhouse to detect herds infected with aujeszky's disease virus, porcine influenza virus and actinobacillus (haemophilus) pleuropneumoniae in the framework of an integrated quality control (iqc) system. | over a period of six months, approximately 4700 blood samples were collected from 97 pig-finishing farms in the provinces of noord-brabant and gelderland and screened for antibodies with respect to aujeszky's disease virus (adv), porcine influenza virus (pi) and actinobacillus (haemophilus) pleuropneumoniae (app). there were significant differences in the percentages of seropositive pigs between the two provinces, which may be related to the difference in the density of the pig population in the ... | 1990 | 2176752 |
| safety of an aujeszky's disease vaccine based on deletion mutant strain 783 which does not express thymidine kinase and glycoprotein i. | the safety of an aujeszky's disease virus vaccine based on strain 783, a deletion mutant which does not express glycoprotein i and thymidine kinase, was assessed in pigs, calves and sheep. four-day-old piglets which were inoculated intranasally and intramuscularly with 10(7) plaque forming units (pfu) developed only slight depression and fever. the virus was transmitted to a sentinel piglet. six weeks after inoculation, the pigs were injected with high doses of corticosteroids in an attempt to r ... | 1990 | 2177288 |
| genetic engineering of the pseudorabies virus genome to construct live vaccines. | pseudorabies virus (prv) is a herpesvirus of pigs. homologous recombination with plasmids offers a method to engineer precise changes in the prv genome to produce advantageous live vaccines. safety can be ensured by using a non-reverting deletion to inactivate the thymidine kinase gene. one particularly important feature of new prv vaccines is deletion of an antigen, so that vaccinated pigs are serologically distinguishable from infected pigs. we have constructed a live vaccine strain with delet ... | 1990 | 2170641 |
| in vivo and in vitro genetic recombination between conventional and gene-deleted vaccine strains of pseudorabies virus. | pseudorabies virus (prv), an alpha-herpesvirus, causes substantial economic losses in the swine industry and is currently the focus of eradication and control programs. some of these programs rely on the ability of veterinarians to differentiate animals exposed to virulent strains of prv from animals exposed to avirulent vaccine strains of prv on the basis of a serologic response to nonessential glycoproteins that are deleted in some vaccine strains of prv. genetic recombination resulting in the ... | 1990 | 2173449 |
| efficacy of a killed gpx deleted pseudorabies virus vaccine. | ten inactivated vaccines containing one of four adjuvants and varying concentrations of pseudorabies virus (prv) antigens were compared in order to select a vaccine suitable for commercial production. a genetically engineered strain of prv lacking the gene coding for glycoprotein x (gpx) was used in these vaccines. vaccinated pigs were challenged intranasally with virulent prv to determine the efficacy of vaccines. vaccination of pigs with one dose of experimental vaccines adjuvanted with 50% mo ... | 1990 | 2174294 |
| evaluation of two commercial elisa test kits for the detection of pseudorabies antibodies in pigs. | 1990 | 1965641 | |
| sandwich enzyme-linked immunosorbent assay (elisa) for measuring the concentration of, and detection of antibodies to, aujeszky's disease virus. | a double antibody sandwich enzyme-linked immunosorbent assay (elisa) was developed for measuring aujeszky's disease virus (adv) antigen concentration and an inhibition technique based on the former was developed for detection of antibodies to adv. the results were checked by determining the cytopathic and serum neutralization titres. the correlation was satisfactory in both cases, with correlation coefficients above 0.8. when measuring adv antigen concentration, the lower limit of detection was ... | 1990 | 1965996 |
| the bamhi j fragment (0.706 to 0.737 map units) of pseudorabies virus is transcriptionally active during viral replication. | the bamhi j fragment of the pseudorabies virus (prv) genome has not been associated with any viral transcripts during viral replication. in this report, data are presented to show that a portion of bamhi-j is transcribed during a productive infection. four oligo(dt)-cellulose-selected rna species were detected by hybridization with probes derived from bamhi-j. these rnas were partially colinear, and they were transcribed in the opposite orientation with respect to the immediate-early gene (ie180 ... | 1990 | 2154623 |
| epitope analysis of glycoprotein i of pseudorabies virus. | a panel of 11 monoclonal antibodies (mabs) raised against pseudorabies virus (prv) was used to map epitopes on the virus glycoprotein i (gi). we employed three approaches to map epitopes on gi. by a competition binding assay, six groups of mabs were defined as reacting with distinct antigenic domains on gi. to identify regions along the gi polypeptide chain encompassing the domains recognized by these mabs, dna fragments derived from the gi-coding region were cloned into pex expression plasmids. ... | 1990 | 1691269 |
| pseudorabies virus glycoprotein gi: in vitro and in vivo analysis of immunorelevant epitopes. | overlapping fragments of the gene encoding glycoprotein gi of pseudorabies virus (prv; herpesvirus suis 1) were expressed in bacteria. using the fusion proteins and a panel of monoclonal antibodies (mabs) against gi as well as swine sera we found that the n-terminal part of gi (residues 33 to approximately 100) contains a highly antigenic and immunogenic domain. transfer of antibodies binding to this region as well as vaccination with fusion proteins containing the n terminus of gi are able to c ... | 1990 | 1693164 |
| a novel concept for the control of aujeszky's disease: experiences in two vaccinated pig herds. | a study was conducted to examine the usefulness of a glycoprotein i (gi)-elisa to monitor aujeszky's disease virus infection in two vaccinated pig herds; the gi-elisa can differentiate between pigs infected with aujeszky's disease virus and pigs vaccinated against aujeszky's disease with gi-negative vaccines. the two herds had been vaccinated with gi-negative vaccines for several years. the first survey, in september 1986, revealed that approximately 10 per cent of the breeding pigs in a large m ... | 1990 | 2155499 |
| a major portion of the latent pseudorabies virus genome is transcribed in trigeminal ganglia of pigs. | pseudorabies virus (prv) is a porcine herpesvirus that establishes latent infections in trigeminal ganglia. to determine whether prv expresses any transcripts that could play a role in latency, the trigeminal ganglia of 14 pigs previously inoculated through the nose and latently infected with prv(ka) were assayed by in situ nucleic acid hybridization for the presence of prv-specific rna. hybridizations employing probes encompassing the entire viral genome revealed that an area extending from 0.6 ... | 1990 | 1697908 |
| comparison between results of virus neutralization test and those of two elisas when screening for antibodies to pseudorabies virus in thailand. | the virus neutralization (vn) test and two enzyme-linked immunosorbent assays (blocking and indirect elisas) were used to detect antibodies to pseudorabies virus on serum samples of 1,000 pigs from the central part of thailand. the results of these tests were compared to those of vn test. using the vn test as standard, the blocking and indirect elisas showed respectively 95.12% and 99.37% relative sensitivity and 92.0% and 93.5% relative specificity. the two elisas were considered both as practi ... | 1990 | 1964525 |
| blocking elisa to distinguish pseudorabies virus-infected pigs from those vaccinated with a glycoprotein giii deletion mutant. | a blocking enzyme-linked immunosorbent assay (elisa) test has been developed to distinguish pseudorabies virus (prv)-infected pigs from those immunized with a glycoprotein g92(giii) deletion mutant, prv(dlg92dltk). the blocking elisa utilizes 96-well microtiter test plates coated with a cloned prv g92(giii) antigen, a mouse monoclonal antibody against giii antigen (momcagiii): horseradish peroxidase (hrpo) conjugate, and undiluted test sera. analyses can be completed in less than 3 hours with re ... | 1990 | 1965296 |
| the detection of antibodies to the glycoprotein x antigen of pseudorabies virus. | the persistence of antibodies to glycoprotein x (gpx) in the serum of pigs experimentally infected with pseudorabies virus (prv) was determined using an anti-gpx enzyme-linked immunosorbent assay (elisa). antibodies to gpx were detected for at least 365 days postchallenge in nonvaccinated pigs. previous sensitization of pigs by vaccination with s/prv had no apparent effect on the antibody response of pigs to gpx postchallenge. in determining previous exposure of pigs to prv strains containing th ... | 1990 | 1965297 |
| aujeszky's disease in a cow. | a non-suppurative encephalitis accompanied by intraneuronal intranuclear inclusions were observed in the brain from a cow that died within 10 hours of developing nervous signs. immunogold-silver staining located aujeszky's disease virus antigen in neuronal cytoplasm and the virus was isolated from large volumes of suspensions of nervous tissues and tonsils. fattening pigs in adjacent buildings had high antibody titres to aujeszky's disease virus. the methods by which the cow could have acquired ... | 1990 | 2154071 |
| [safety aspects of the practical application of a gi-negative subunit vaccine against aujeszky's disease in swine]. | on two farms in an area in which aujeszky's disease is endemic, 192 pregnant sows were vaccinated with a gi-negative sub-unit vaccine against aujeszky's disease. the rectal temperatures of the sows were recorded once daily for seven consecutive days, starting on the day of vaccination, and the vaccinated animals were observed for local and systemic reactions. the temperatures recorded did not exceed 39.8 degrees c in any case, and local or systemic reactions caused by vaccinations were not obser ... | 1990 | 2154870 |
| detection by enzyme-linked immunosorbent assay of aujeszky's disease virus in tissues of infected pigs. | an enzyme-linked immunosorbent assay was developed for the detection of aujeszky's disease virus antigen in tissue extracts and in nasal swabs. the enzyme-linked immunosorbent assay is based on two different monoclonal antibodies with specificity for the gii glycoprotein of aujeszky's disease virus. viral antigen was detected in 81 of 93 tissue extracts prepared from virus-infected organs. fifteen outbreaks of aujeszky's disease were analyzed in this study, and they were all identified by the gi ... | 1990 | 2155919 |
| factors associated with circulation of pseudorabies virus within swine herds. | data were collected from 104 minnesota swine farms quarantined for pseudorabies virus (prv) infection. each herd was serologically evaluated for the presence of antibodies to prv in finishing pigs. herd management practices, swine housing design, and disease profiles were described for each farm. multiple logistic regression analysis was used to determine which factors were associated with circulation of prv in the finishing pigs of farrow-to-finish farms. sixty-seven (64%) of the herds had no s ... | 1990 | 2155892 |
| pseudorabies virus latency and reactivation in vaccinated swine. | latency and reactivation of pseudorabies virus in swine was studied. thirty-one pigs were assigned to 5 groups and were given 1 of 4 vaccines; 10 remained unvaccinated controls. all pigs were then challenge exposed with a sublethal dose of virulent pseudorabies virus. one hundred one days after challenge exposure, all pigs were treated with dexamethasone to reactivate the virus. virus-positive tonsil and nasal mucus isolates were recovered from 29 of the 31 pigs over a 12-day period. frequency a ... | 1990 | 2156472 |
| reactivation of latent pseudorabies virus infection in vaccinated commercial sows. | pseudorabies virus (prv) was isolated from 9 of 44 prv-vaccinated seropositive sows on 5 of 11 farms. although serum-neutralization antibody titers were 1:16 to 1:256, 28 virus isolates were obtained from tonsil, nasal, or buccal swab samples from 9 sows given 2 ml of dexamethasone/kg of body weight im for 5 days. pseudorabies virus was isolated from 6 of 20 sows (3 of 5 farms) given a killed-virus vaccination. virus was obtained from 3 of 24 sows (2 of 6 farms) given modified-live virus and kil ... | 1990 | 2156473 |
| a study comparing the immunologic responses of swine to pseudorabies viral antigens based on the elisa, serum virus neutralization, and latex agglutination tests. | a study of pseudorabies virus (prv)-vaccinated pigs comparing the immune responses detected by the latex agglutination test (lat) with responses detected by other routine tests for pseudorabies antibodies indicated that lat was more sensitive than either the enzyme-linked immunosorbent assay (elisa) or the serum virus neutralization test (svnt). the lat detected antibodies sooner than elisa and svnt in unvaccinated pigs after challenge with virulent prv. the specificities of the 3 tests were fou ... | 1990 | 1965298 |
| sequential changes in the humoral immune response of pigs to pseudorabies virus after vaccination, exposure to virulent virus, and reactivation of latent virus. | sequential changes in the humoral immune response of pigs to pseudorabies virus (prv) after each of several exposures to the virus were evaluated by determining virus neutralization (vn) and radioimmunoprecipitation (rip) activities of sera collected at selected intervals. pigs were vaccinated intramuscularly with live attenuated virus (6 pigs), inactivated attenuated virus (6 pigs), or inactivated virulent virus (6 pigs). all pigs were challenged oronasally with virulent virus 3 weeks later and ... | 1990 | 1965299 |
| genetically engineered vaccines for control of aujeszky's disease (pseudorabies). | a gene-deleted pseudorabies (pr) (aujeszky's disease) vaccine, named omnivac-prv, was licensed by the united states department of agriculture-animal and plant health inspection service (usda-aphis) on january 16, 1986, the first recombinant dna-derived modified-live virus vaccine to be licensed for manufacture and sale anywhere in the world. two months later, a second generation gene-deleted 'marker' vaccine, omnimark-prv, was described. surprisingly, these landmark applications of genetic engin ... | 1990 | 2174594 |
| detection of latent pseudorabies virus in swine using in situ hybridization. | we have examined methods for detection of pseudorabies virus (prv) latency in three groups of swine; naturally infected animals obtained from a field case; animals which have been experimentally infected with becker or iowa strains of prv; and single reactors (single seropositive animals within prv-free herds). in situ hybridization was shown to be more sensitive than explanation/co-cultivation for the detection of latent virus. nervous tissues, in particular the trigeminal ganglia, were found t ... | 1990 | 2175525 |
| polymerase chain reaction amplification of pseudorabies virus dna from acutely and latently infected cells. | a characteristic of alphaherpesviruses, including pseudorabies virus (prv), is that the acute phase of the disease is followed by lifelong latency. latently infected animals are asymptomatic but can transmit reactivated virus. corticosteroid administration, tissue explanation, blot- and in situ hybridizations have been used to demonstrate the presence of latent prv infections. the use of blot hybridization as a convenient method for defining the incidence of prv infections in swine herds has bee ... | 1990 | 2175526 |
| establishment of transformed swine fibroblast cell lines using sv40 large t antigen. | swine testicle cell lines were established by transformation of primary swine testicle (pst) cells with an sv40 plasmid (psv3-neo), which contains genes conferring resistance to neomycin and expressing sv40 large t antigen. plasmid dna was transfected into pst cells using a lipofection system. two related plasmids, psv2-neo and psv5-neo, failed to induce transformed cells. cells transformed with psv3-neo formed single colonies that were resistant to the antibiotic, g418, and expressed large t an ... | 1990 | 2175590 |
| detection of porcine parvovirus using nonradioactive nucleic acid hybridization. | nonradioactive slot blot hybridization assays were established for the detection of porcine parvovirus (ppv), using either a digoxigenin-labeled dna probe or a biotinylated rna probe. all probes were prepared from a 3.3-kb pst1-ecor1 dna fragment of the nadl8 isolate of ppv. the sensitivity and specificity of the probes in a slot blot system were evaluated in comparison with a 32p-radiolabeled rna probe. using an anti-digoxigenin alkaline phosphatase detection system, at least 1 ng of viral repl ... | 1990 | 1965580 |
| pseudorabies virus glycoprotein giii is a major target antigen for murine and swine virus-specific cytotoxic t lymphocytes. | pseudorabies virus (prv) is the etiological agent of aujeszky's disease, a disease that causes heavy economic losses in the swine industry. a rational approach to the generation of an effective vaccine against this virus requires an understanding of the immune response induced by it and of the role of the various viral antigens in inducing such a response. we have constructed mutants of prv [strain prv (ka)] that differ from each other only in expression of the viral nonessential glycoproteins g ... | 1990 | 2153244 |
| financial analysis of pseudorabies control and eradication in swine. | computerized decision-tree analysis and simulation modeling were used to evaluate control and eradication strategies for pseudorabies virus (prv) in swine. three alternative actions were considered for a hypothetical 100-sow, farrow-to-finish operation: (1) depopulation-repopulation, (2) test-and-removal of seropositives (t&r), and (3) vaccination (of the entire herd or of sows only). the expected monetary values for the vaccination and t&r alternatives were similar, which was consistent with th ... | 1990 | 2266046 |
| detection of aujeszky's disease virus in nasal cells of fattening pigs by immunoassay. | both conventional and specific pathogen free pigs were inoculated intranasally with a strain of aujeszky's disease virus (adv). nasal cells were collected daily by swab, aspiration or wash. the nasal cells were examined for adv by isolation on cell culture, direct or indirect immunofluorescence and immunoperoxidase staining by monoclonal antibodies. the infected pigs were studied for nasal shedding of infected cells until 30 days after infection. the study was also extended to naturally infected ... | 1990 | 2154020 |
| humoral immune response to immediate-early protein of pseudorabies virus in swine with induced or naturally acquired infection. | pseudorabies virus (prv) immediate-early (ie) protein is a nonglycosylated polypeptide localized in the nuclei of infected cells. the ie protein is a regulatory protein that is only synthesized during viral replication and is presented to the immune system of prv-infected swine. antibodies to the ie protein were demonstrated in swine with induced or naturally acquired infection. however, antiserum raised against purified ie protein could not neutralize prv in vitro. | 1990 | 2154150 |
| elisa detection of aujeszky's disease virus antibodies. | 1990 | 2155498 | |
| pseudorabies virus latency: restricted transcription. | cloned pseudorabies virus (prv) sequences representing over 80% of the viral genome were radiolabeled and individually hybridized to nucleic acid in the trigeminal ganglia of acutely and latently infected swine. in acutely infected animals, all cloned probes hybridized to prv rna and dna. in contrast, during latency transcription was found to be limited to a selected region, corresponding to the ie gene, analogous to that of two other alpha-herpesviruses. viral dna was not detected in latently i ... | 1990 | 2155596 |
| inactivation of the thymidine kinase gene of a gi deletion mutant of pseudorabies virus generates a safe but still highly immunogenic vaccine strain. | in an earlier report, we described the construction of the genetically engineered pseudorabies virus strain 2.4n3a which does not express glycoprotein gi. although this strain showed a strongly reduced virulence in 10-week-old seronegative pigs, it could still cause severe disease or death in 3-day-old piglets. to attenuate the strain further, we constructed mutants with a deletion in the viral thymidine kinase gene. one mutant strain, designated 783, has a deletion of 19 base pairs and was show ... | 1990 | 2165138 |
| comparative pathology of hpcd pigs infected with wild-type and ara-t-resistant strains of aujeszky's disease virus. | fourteen 1- to 4-week-old hysterectomy-produced and colostrum-deprived (hpcd) pigs were inoculated intranasally with wild-type and ara-t-resistant strains of aujeszky's disease virus (adv), and the pathological lesion induced by the two strains was compared. the wild-type strain (ys-81) led to high mortality, and the pigs developed multifocal necrosis throughout the body and encephalitis. in comparison, the ara-t-resistant strain (ys-81tr) of the virus killed only 1-week-old hpcd pigs inoculated ... | 1990 | 2155950 |
| [vaccinations in pigs]. | efficacious and safe gi-negative vaccines are available for vaccination against aujeszky's disease. an intensive vaccination programme carried out consistently will result in the reduction of virus circulating among pig populations. combined vaccination and culling of gi-seropositive pigs may lead to eradication of aujeszky's disease virus in a stock. vaccination of susceptible gilts, sows and boars against parvovirus infections is advisable. the actual period for which a sow is protected agains ... | 1990 | 2161569 |
| extent and duration of virulent virus excretion upon challenge of pigs vaccinated with different glycoprotein-deleted aujeszky's disease vaccines. | different deleted aujeszky's disease vaccines were compared for their ability to induce an immunity which suppresses virus excretion optimally upon infection. groups of pigs were vaccinated once with attenuated deleted aujeszky's disease vaccine (gi, gx or gp63 negative), suspended in phosphate buffered saline. two additional groups were vaccinated with a gi deleted vaccine virus suspended in an oil-in-water emulsion. other groups were vaccinated twice with gi deleted inactivated vaccines. the t ... | 1990 | 2162094 |
| neurotropic properties of pseudorabies virus: uptake and transneuronal passage in the rat central nervous system. | uptake, replication, and transneuronal passage of a swine neurotropic herpesvirus (pseudorabies virus, prv) was evaluated in the rat cns. prv was localized in neural circuits innervating the tongue, stomach, esophagus and eye with light microscopic immunohistochemistry. in each instance, the distribution of prv-immunoreactive neurons was entirely consistent with that observed following injection of cholera toxin-horseradish peroxidase conjugate (ct-hrp). injections of the tongue resulted in retr ... | 1990 | 2162388 |
| the 5' and 3' limits of transcription in the pseudorabies virus latency associated transcription unit. | while latent in sensory neurons of infected pigs, pseudorabies virus expresses transcripts from a limited genomic area. these rnas are transcribed from the strand opposite to that which encodes the pseudorabies immediate-early protein. using a combination of in situ nucleic acid hybridization performed on latently infected pig trigeminal ganglia and dna sequencing, 5' and 3' limits of transcription for the pseudorabies lat transcription unit have been defined. the 5' limit of transcription has b ... | 1991 | 1850931 |
| pseudorabies virus infections in explants of porcine nasal mucosa. | the spread of infection and the morphogenesis of three pseudorabies virus strains were studied in explants of porcine nasal mucosa. virulent nia-3 virus was compared with a deletion mutant 2.4n3a, and with a non-virulent bartha virus. all three virus strains infected nasal epithelial cells. nia-3 virus particles were enveloped mainly at the inner nuclear membrane; the virus rapidly invaded the stroma, causing widespread necrosis. in contrast, 2.4n3a virus particles were enveloped mainly at the e ... | 1991 | 1646473 |
| sensitive glycoprotein giii blocking elisa to distinguish between pseudorabies (aujeszky's disease)-infected and vaccinated pigs. | a blocking enzyme-linked immunosorbent assay (elisa) test has been developed to distinguish pseudorabies virus (prv) (aujeszky's disease virus) -infected pigs from those immunized with a glycoprotein g92 (giii) deletion mutant, prv (dlg92dltk) [omnimark-prv]. this blocking elisa test utilizes an anti-prv giii monoclonal antibody (mabgiii)-horseradish peroxidase (hrpo) conjugate, tmb for color development and a cloned prvg92 (giii) antigen to coat wells of microtiter test plates. undiluted sera a ... | 1991 | 1651582 |
| vaccination of pigs against aujeszky's disease by the intradermal route using live attenuated and inactivated virus vaccines. | inactivated and live aujeszky's disease virus vaccines were administered intradermally using a special device without a needle. the 88 pigs were vaccinated at the beginning of the fattening period, both under experimental conditions and in commercial herds. all the pigs were challenged at the end of the fattening period in isolation units. the same vaccines were also injected intramuscularly. vaccination by the intradermal route induced good protection, similar to that conferred with live virus ... | 1991 | 1850888 |
| [the presence of antibodies against glycoprotein i (gi) of the virus of aujeszky's disease in colostrum and milk of sows]. | the possibility of using sow's milk to detect antibodies to the gi protein of aujeszky's virus was studied by the present authors. antibody titres in serum (collected less than 30 days ante partum) and colostrum from sixty-three sows were determined using a commercially available elisa; twenty-four of thirty-seven animals vaccinated with gi-positive vaccines showed an antibody response in both colostrum and serum. the titre in colostrum was significantly higher than it was in serum. antibodies c ... | 1991 | 1851579 |
| immune response in pigs to aujeszky's disease viruses defective in glycoprotein g1 or gx. | two aujeszky's disease virus glycoprotein genes, gx and g1, have been used to produce deletion mutants which have then been developed into vaccines. these deletions then allow differentiation between pigs infected with wild type virus and those given the vaccine. it is not clear whether the glycoproteins encoded for by these genes are needed to induce a full protective immune response, in which case deletion mutants would suffer from lack of potency. to test this, commercially available aujeszky ... | 1991 | 1852057 |
| polymerase chain reaction (pcr) amplification for the detection of porcine parvovirus. | a polymerase chain reaction (pcr) amplification method was developed and evaluated to detect porcine parvovirus (ppv). a pair of 20-base primers and an oligonucleotide probe were derived from the dna sequences common to two isolates of ppv, nadl-8 and nadl-2. the primers flanked 118-bp nucleotides within the region coding for the major structural protein vp2. after dna amplification of ppv replicative form (rf), a 158-bp fragment was detected in agarose gels. this amplified fragment was shown to ... | 1991 | 1874916 |
| immunohistological demonstration of spread of aujeszky's disease virus via the olfactory pathway in hpcd pigs. | the spread of aujeszky's disease virus (adv) from nasal mucosa via the olfactory pathway was studied in hpcd pigs. adv antigen was detected in the epithelial cells, nasal gland cells, olfactory nerve cells and peripheral nerve fibres in the nasal cavity and in neuroglial cells in the olfactory bulb. results indicate that the olfactory pathway is one of the most important neuronal pathways of adv infection in pigs. | 1991 | 1663956 |
| antibody response to glycoprotein i in maternally immune pigs exposed to a mildly virulent strain of pseudorabies virus. | to study the antibody response to glycoprotein i (gi) of pseudorabies virus (prv) in maternally immune pigs, 3 groups of 6 pigs were given low doses of the mildly virulent sterksel strain of prv at 3 and 11 weeks of age. group a consisted of seronegative pigs; groups b and c consisted of pigs with maternal antibodies deficient of antibodies to gi. at 3 weeks of age, 3 pigs of each group were inoculated intranasally with 10(2.5) plaque-forming units (groups a and b), or with 10(3.5) plaque-formin ... | 1991 | 1664670 |
| investigation of sites of pseudorabies virus latency, using polymerase chain reaction. | pseudorabies virus (prv) latency was investigated, using polymerase chain reaction (pcr). a pcr protocol was developed that specifically amplified a 217-base pair sequence within the gene encoding the essential glycoprotein gp50 of prv. using this pcr procedure, the gp50 sequence was amplified from tissues of pigs infected with various doses of prv (becker strain). at postinoculation day 64, viral isolation was performed on nasal swab specimens and homogenates of tonsils and trigeminal nerve gan ... | 1991 | 1664672 |
| effect of brefeldin a on alphaherpesvirus membrane protein glycosylation and virus egress. | in this work we used brefeldin a (bfa), a specific inhibitor of export to the golgi apparatus, to study pseudorabies virus viral glycoprotein processing and virus egress. bfa had little effect on initial synthesis and cotranslational modification of viral glycoproteins in the endoplasmic reticulum (er), but it disrupted subsequent glycoprotein maturation and export. additionally, single-step growth experiments demonstrated that after the addition of bfa, accumulation of infectious virus stopped ... | 1991 | 1847436 |
| factors associated with the seroprevalence of pseudorabies virus in breeding swine from quarantined herds. | strategies for the elimination of pseudorabies virus (prv) from swine herds include test and removal, offspring segregation, and depopulation/repopulation. the prevalence of prv in a herd is a major factor in selection of the most appropriate strategy. the purpose of the study reported here was to describe the prevalence of prv in adult swine in prv quarantined herds in minnesota, and to determine herd factors associated with the seroprevalence. questionnaires describing the health history of th ... | 1991 | 1664820 |
| the genome type of aujeszky's disease virus isolated from a cat in japan. | 1991 | 1665082 | |
| non-pathogenic strains of aujeszky's disease virus are not reactivated in swine after corticosteroid treatment. | 1. the bartha-k and nia-4 strains of aujeszky's disease virus (adv) were readily isolated from oropharyngeal swabs up to 7 days after intranasal vaccination of young piglets. 2. neither strain could be reisolated 14 days after starting treatment with 10 mg of the corticosteroid isoflupredone acetate per kg of body weight, administered intramuscularly for 4 consecutive days when pigs were 7-9 months of age. 3. similar treatment with corticosteroid pigs infected with two virulent adv strains resul ... | 1991 | 1668397 |
| the genomic diversity and stability of field strains of suid herpesvirus 1 (aujeszky's disease virus). | the genomic diversity among isolates of suid herpesvirus 1 (shv-1) collected in the same herd and among clones from the same isolate was studied by restriction fragment pattern (rfp) analysis using bamhi. tentatively defining a field strain as a transmissible entity, it was concluded that strains of shv-1 commonly comprise distinguishable genomic variants. contrary to the hypothesis of genomic lability, it is suggested that the pool of variants is sufficiently stable to specifically characterize ... | 1991 | 1673808 |
| pig herds having a single reactor to serum antibody tests to aujeszky's disease virus. | the introduction of aujeszky's disease virus into a herd of pigs usually results in a rapid spread of the virus and a high percentage of pigs become seropositive. however, herd monitoring for the virus occasionally reveals a single seropositive breeding pig, referred to as a single reactor. the seropositive status of single reactors may be due to previous vaccination against aujeszky's disease, or to exposure to a field strain of the virus, or to a false positive reaction in the serological assa ... | 1991 | 1848382 |
| factors associated with spread of pseudorabies virus among breeding swine in quarantined herds. | knowledge of the factors that place susceptible gilts at highest risk of pseudorabies virus (prv) infection in a quarantined herd is crucial to reduce spread of prv within the herd. cohorts of prv seronegative gilts were monitored in 17 herds that were endemically infected with prv to determine the location of breeding females at the time of infection with prv and identify herd characteristics and management and housing factors that may influence spread of prv in the breeding section of swine he ... | 1991 | 1653190 |
| efficacy of a pseudorabies virus vaccine based on deletion mutant strain 783 that does not express thymidine kinase and glycoprotein i. | the vaccine efficacy of a genetically engineered deletion mutant strain of pseudorabies virus, strain 783, was compared with that of the conventionally attenuated bartha strain. strain 783 has deletions in the genes coding for glycoprotein i and thymidine kinase. in experiment 1, which had a 3-month interval between vaccination and challenge exposure, strain 783 protected pigs significantly (p less than 0.05) better against virulent virus challenge exposure than did the bartha strain. the growth ... | 1991 | 1654033 |
| the influence of porcine recombinant interferon-alpha 1 on pseudorabies virus infection of porcine nasal mucosa in vitro. | to determine the effect of interferon (ifn) on the pathogenesis of pseudorabies virus (prv), porcine nasal mucosal explants were first treated with recombinant porcine methionyl-ifn-alpha 1 and then infected with one of three strains of prv. the stroma of treated mucosal explants were protected against infection with virulent prv or prv of intermediate virulence because the infection was restricted to the epithelial cells. in contrast, untreated mucosal explants were readily infected by virulent ... | 1991 | 1849975 |