| isolation and characterization of mutants of pseudorabies virus with deletion in the immediate-early regulatory gene. | pseudorabies virus (prv) immediate-early regulatory protein (ie180) is a potent and promiscuous activator of viral and cellular gene transcription. a mutant with deletion in the ie180 gene is expected to be useful for elucidating the functions of ie180. in this study, we constructed such mutants. initially, transformants that express ie180 were established from pk-15 and vero cells by transfection with the ie180 gene of the wild-type prv. two types of the deletion mutant could be obtained by usi ... | 1994 | 8122367 |
| evaluation of swinepox virus as a vaccine vector in pigs using an aujeszky's disease (pseudorabies) virus gene insert coding for glycoproteins gp50 and gp63. | pigs were vaccinated by scarification or intramuscular injection with a swinepox virus-aujeszky's disease (pseudorabies) recombinant (rspv-ad) constructed by inserting the linked aujeszky's disease virus genes coding for glycoproteins gp50 and gp63, attached to a vaccinia virus p7.5 promoter, into the thymidine kinase gene of swinepox virus. by 21 days after vaccination, 90 and 100 per cent of the animals vaccinated by scarification or intramuscular injection, respectively, had developed serum n ... | 1994 | 8128561 |
| vaccination of pigs against pseudorabies with highly attenuated vaccinia (nyvac) recombinant viruses. | poxvirus recombinants, based on the highly attenuated nyvac strain of vaccinia virus (tartaglia et al., 1992), containing single gene inserts encoding the pseudorabies virus (prv) gii, giii, or gp50 glycoproteins were tested for their immunogenicity in pigs. twenty-four pigs were randomly divided into six groups of four. groups 1-3 were inoculated with 10(7) ccid50 of nyvac/prv gii, nyvac/prv giii, or nyvac/prv gp50, respectively, while groups 4 and 5 received the nyvac parent virus or an inacti ... | 1993 | 8128602 |
| evaluation of a recombinant vaccinia virus containing pseudorabies (pr) virus glycoprotein genes gp50, gii, and giii as a pr vaccine for pigs. | pigs vaccinated twice intramuscularly with a highly attenuated strain of vaccinia virus (nyvac) containing gene inserts for pseudorabies virus (prv) glycoproteins gp50, gii, and giii produced neutralizing antibodies for prv and were less clinically affected than were nonvaccinated pigs following oronasal exposure to virulent prv. also, following oronasal exposure to virulent prv the duration of virulent virus shedding by pigs that had been vaccinated intramuscularly with the recombinant virus wa ... | 1994 | 8129615 |
| [the control of aujeszky's disease using surface vaccination. 2. serologic studies of the occurrence of latent infection by aujeszky's disease virus in fattening swine]. | the aim of the study was to prove in a region in the north-west of germany that there is the possibility to decrease the prevalence of latent aujeszky's disease infections by means of a systematic vaccination. for this, the most important precondition of the success in a high population immunity that is maintained also in the finishing pig until slaughter. since it is known that maternal antibodies interfere with the active immunization in the prefattening period, procedures were to be found tha ... | 1994 | 8131724 |
| [prevalence of antibodies against the viruses of european swine fever, aujeszky's disease and "porcine reproductive and respiratory syndrome" in wild boars in the federal states sachsen-anhalt and brandenburg]. | during the hunting season from 1991/1992 blood samples were collected from wild boar shot in the federal states of sachsen-anhalt (482 samples) and brandenburg (177 samples) which corresponds to 2.1 and 0.4% of the total hunting bag. all sera were screened in a complex trapping blocking (ctb) elisa for antibodies against hog cholera virus (hcv) and in an indirect elisa for antibodies against aujeszky's disease virus (adv). additionally the sera were tested for neutralizing antibodies against hcv ... | 1994 | 8131731 |
| influence of vaccine medium and vaccination schedules on the induction of active immunity against aujeszky's disease in maternally immune pigs. | active immunity against aujeszky's disease virus (adv) was compared at the end of the fattening period in pigs which had been vaccinated with the attenuated bartha strain according to different schedules in the presence of different levels of maternal immunity. the percentage of seropositive pigs at the end of the fattening period varied from 21 to 94 per cent. the percentage was significantly higher when the vaccination schedules were applied to pigs from mothers vaccinated with an attenuated s ... | 1994 | 8146460 |
| optimizing semen production for artificial insemination in swine. | efficient production of high quality semen is of major importance to artificial insemination (ai) organizations. the semen produced should be free of contagious organisms, be of high quality, have good storage properties, fertilizing capacity and be of high genetic value. the best approach to prevent the spreading of microorganisms via semen in the process of ai is to collect semen from boars free from specific diseases, for example pseudorabies virus or leptospirosis. antibiotics are added to t ... | 1993 | 8145205 |
| spontaneous fusions to prv43 can suppress the export defect of pseudorabies virus giii signal peptide mutants. | we have devised an enrichment scheme for the isolation of export-competent derivatives of pseudorabies virus glycoprotein giii signal peptide mutants. enrichment is based upon a growth advantage imparted upon giii-containing virions compared with virions lacking the glycoprotein. each of identified derivatives suppressed the giii signal peptide defect by fusing the giii gene in frame to the prv43 gene that lay immediately upstream; the result was the synthesis of a prv43-giii hybrid protein. the ... | 1994 | 8151750 |
| a serologic survey of selected viral and bacterial diseases of european wild hogs, great smoky mountains national park, usa. | blood samples were collected from 108 wild hogs (sus scrofa) from the great smoky mountains national park (gsmnp), usa, february to july 1990. we found no antibodies for swine brucellosis, pseudorabies, bovine virus diarrhea virus or porcine rotavirus infection. antibody titers to porcine parvovirus were found in 15 (14%) samples and antibody to one or more leptospiral serovars was found in 48 (44%) samples. thirty-nine (89%) of the 44 positive samples reacted to all five leptospiral serovars te ... | 1994 | 8151810 |
| non-transmissible pseudorabies virus gp50 mutants: a new generation of safe live vaccines. | envelope glycoprotein gp50 of pseudorabies virus (prv) is essential for virus entry, but is not required for subsequent steps in the viral replication cycle. phenotypically-complemented gp50 null mutants can infect cells and can spread, both in vitro and in vivo, by direct cell-to-cell transmission. however, progeny virions released by the infected cells are non-infectious because they lack gp50. therefore, these viruses cannot be transmitted from infected animals to contact animals. these prope ... | 1994 | 8178562 |
| vaccination of maternally immune pigs with a live aujeszky's disease vaccine by coarse spray and other routes. | 33 ten weeks old passively immune weaners were inoculated with live, attenuated aujeszky's disease (ad) vaccine, according to four different vaccination protocols: (groups a/a2) 3 x coarse spray vaccination at 10, 11 and 13 weeks of age, (groups b/b2) 1 x coarse spray at 10 weeks of age followed by 1 x intramuscularly at 13 weeks, (c) 1 x intranasal instillation at 10 weeks of age, and (groups d/d2) 2 x intramuscularly at 10 and 13 weeks of age. a further 10 weaners were included as unvaccinated ... | 1994 | 8203117 |
| [vaccination recommendation for aujeszky disease]. | | 1994 | 8191487 |
| spread of aujeszky's disease virus within pig herds in an intensively vaccinated region. | an intensive vaccination programme with the glycoprotein i (gi) and thymidine kinase-deleted vaccine strain 783 was applied on all the pig farms in a region with a high pig density. to monitor the spread of aujeszky's disease virus within breeding herds in that region, all the breeding stock in nine herds were examined for antibodies to gi six times at intervals of four months. the prevalence of gi-seropositive sows decreased greatly in all nine herds. the mean percentage of gi-seropositive sows ... | 1994 | 8203108 |
| suitability of autoclaved tap water for preparation of elisa reagents and washing buffer. | the suitability of autoclaved tap water for the preparation of elisa reagents and washing buffer was compared with that of ultrapure water, in a standard indirect elisa for the detection of antibodies to pseudorabies virus (prv). the performance of the assay, using autoclaved tap water (at-elisa) compared favourably to that of the standard assay, using ultrapure water (up-elisa) in detecting anti-prv antibodies in sequential serum samples from a pig experimentally infected with prv. while both t ... | 1994 | 8188820 |
| rapid identification and quantitation of cells infected by recombinant herpesvirus (pseudorabies virus) using a fluorescence-based beta-galactosidase assay and flow cytometry. | we recently described construction and use of a beta-galactosidase expression cassette in isolating recombinant pseudorabies virus (prv) mutants (mettenleiter and rauh, 1990). we report here the identification and exact quantitation of cells infected by these mutants using an assay based on the reaction of intracellular beta-galactosidase expressed during infection by the recombinant viruses with the fluorogenic substrate fluorescein di-beta-d-galactopyranoside (fdg) followed by detection of pos ... | 1993 | 8227283 |
| role of pseudorabies virus glycoprotein ii in protection from lethal infection. | a monoclonal antibody (mab), named 1.21, with complement-dependent neutralizing activity was produced against glycoprotein ii (gii) of pseudorabies virus (prv). by immunoaffinity chromatography using a mab 1.21 column, gii was purified from nonidet p40-lysates of prv infected bhk21/13 cells. when mice and pigs were immunized with purified gii, complement-dependent virus-neutralizing antibodies were produced. the immunized animals survived potentially lethal challenge with prv. these results indi ... | 1993 | 8236782 |
| [the effect of 3 times per year random vaccination of sows against aujeszky's disease on maternal immunity in a breeding farm]. | research was undertaken to study the effect of a 'three times a year vaccination schedule in sows' against aujeszky's disease (ad) on the maternal immunity of their offspring at a large pig farm. only gi-negative sows and piglets were induced in the study. the maternal immunity was measured in the 8-week-old offspring of 6 gilts and 13 sows, vaccinated in early pregnancy and in 8-week-old piglets born from 12 gilts and 21 sows vaccinated 3 weeks prior to farrowing. at an age of 8 weeks only 5 pe ... | 1993 | 8266305 |
| circumvention of maternal antibody interference by immunization of newborn pigs with glycoprotein giii-deleted marker vaccine. | maternal antibodies interfere with the immunization of swine by modified live-virus pseudorabies virus (prv) vaccines. to test the hypothesis that a prv vaccine attenuated by deletions in the thymidine kinase (tk) and giii genes might reduce interference by maternal antibodies, pigs with moderate to low levels of colostral prv antibodies were immunized with the tk- giii-omnimark-prv vaccine. vaccinates and non-vaccinates were challenged intranasally with virulent prv at 7 weeks of age. in suppor ... | 1993 | 8270271 |
| efficacy of various non-oily adjuvants in immunization against the aujeszky's disease (pseudorabies) virus. | standard oil and various non-oily adjuvants were compared for use in immunization against the aujeszky's disease (pseudorabies) virus, both in mice and swine, and using either inactivated virions or purified glycoproteins as antigen. mineral oil, sodium alginate, aluminium hydroxide, and saponin were assayed in mice as adjuvants for inactivated virions, saponin being the most efficient. the addition of mab anti-cd3 did not improve either immune response or protection achieved in mice using viral ... | 1993 | 8237208 |
| passively transferred african swine fever virus antibodies protect swine against lethal infection. | the role of anti-viral antibodies in homologous protective immunity to a virulent african swine fever virus (asfv) strain e75 was examined by passive transfer experiments in swine. eighty-five percent of animals (n = 14) that received anti-asfv immunoglobulin (ig) survived challenge infection, while 100% mortality was observed in control group animals (n = 28) that received anti-pseudorabies virus ig, normal swine ig, or phosphate-buffered saline. with the exception of a significantly delayed an ... | 1994 | 8259670 |
| comparison of in vivo reactivation, in vitro reactivation, and polymerase chain reaction for detection of latent pseudorabies virus infection in swine. | the following methods were compared for their ability to detect latent pseudorabies virus in 24 pigs that had been experimentally infected with virulent pseudorabies virus: 1) in vivo reactivation by dexamethasone administration, 2) in vitro reactivation by 5 different techniques of explant culture or cocultivation of trigeminal ganglia, and 3) detection of pseudorabies virus genome in tissue digests of tonsils or trigeminal ganglia using the polymerase chain reaction. reactivation of pseudorabi ... | 1993 | 8286446 |
| evaluation of serological pseudorabies tests for the detection of antibodies during early infection. | six enzyme-linked immunosorbent assays, a latex agglutination test, and the standard microtitration serum virus neutralization test were compared for their ability to detect antibodies against pseudorabies virus (prv) during the early stages of infection. thirty-five pigs were infected intranasally with 10(5)-10(7) tcid50 of either the iowa 4892 pneumotropic or the becker strain of prv. blood samples were drawn from experimentally inoculated animals on days 4-10, 14, and 21 postchallenge. test s ... | 1993 | 8286450 |
| distinction between aujeszky's disease virus-infected and vaccinated pigs by hemagglutination-inhibition test. | a hemagglutination-inhibition (hi) test was applied to distinguish virulent aujeszky's disease virus infected pigs from those immunized with a glycoprotein giii deletion vaccine. the vaccine strain, dlg92/dltk, did not have hemagglutination activity with mouse erythrocytes and the pigs vaccinated five times with the dlg92/dltk strain failed to develop hi antibody, although they developed neutralizing antibody with 128 to 512 titers to aujeszky's disease virus. on the other hand, these pigs produ ... | 1993 | 8286546 |
| spatiotemporal responses of astrocytes, ramified microglia, and brain macrophages to central neuronal infection with pseudorabies virus. | we examined the responses of astrocytes, ramified microglia, and brain macrophages to cns neuronal infection with virulent or attenuated strains of a swine alpha herpesvirus (pseudorabies virus, prv). after prv inoculation of the rat stomach or pancreas, the temporal course of viral replication and induced pathology of infected neurons were assessed in the dorsal motor nucleus of the vagus (dmv) and amygdala using an antiserum generated against prv. specific monoclonal antibodies against glial f ... | 1993 | 8381171 |
| gene specific assay to differentiate strains of pseudorabies virus. | the need for compatibility between pseudorabies vaccination and disease eradication measures has caused the production and release of diverse pseudorabies virus (prv) vaccine strains with altered genetic makeups due to the deletion of specific genes. these genes code for antigens used as differential serologic markers. by use of polymerase chain reaction (pcr), it is possible to determine, in a rapid and sensitive way, if a given prv strain has a "wildtype" genotype, or if instead it carries a d ... | 1993 | 8384738 |
| glycoprotein gp50-negative pseudorabies virus: a novel approach toward a nonspreading live herpesvirus vaccine. | essential herpesvirus glycoproteins are involved in membrane fusion processes during infection, e.g., viral penetration and direct cell-to-cell transmission. we previously showed that the gd-homologous glycoprotein gp50 of pseudorabies virus (prv) is essential for virus entry into target cells but proved to be dispensable for direct viral cell-to-cell spread in cell culture (i. rauh and t. c. mettenleiter, j. virol. 65:5348-5456, 1991). for gp50-negative (gp50-) viruses, after phenotypic complem ... | 1993 | 8382308 |
| ribonucleotide reductase-deficient mutants of pseudorabies virus are avirulent for pigs and induce partial protective immunity. | we have mutagenized and mapped the gene encoding the large subunit of ribonucleotide reductase (rr1) in pseudorabies virus (prv; synonyms aujeszky's disease virus, suid herpesvirus type 1). prv strains carrying an oligonucleotide that leads to termination of translation of the rr1 gene are avirulent for mice. we subsequently constructed a prv strain carrying a deletion in the rr1 gene and also a prv strain carrying both the deletion in the rr1 gene and a deletion in the glycoprotein g1 gene, whi ... | 1993 | 8383170 |
| a new method for rapidly removing contaminating micro-organisms from porcine parvovirus or pseudorabies virus master-seed suspensions. | virus-contaminated cell cultures are a major problem in the bio-industry. methods employed to date to remove contaminating micro-organisms are slow and costly, and a new method is proposed here which is simple and rapid. the method uses polyacrylamide beads coated with specific antibodies which yielded bead-antibody-virus complexes when suspended in the virus solution to be cleared. the purified virus was propagated in cells which show phagocytic activity. vaccine master-seed virus is shown to b ... | 1993 | 8383386 |
| overall signal sequence hydrophobicity determines the in vivo translocation efficiency of a herpesvirus glycoprotein. | we have described three mutant strains of pseudorabies virus that contain mutations in the signal sequence coding region of a nonessential envelope glycoprotein, giii. the alterations disrupt, truncate, or eliminate the hydrophobic core domain of the signal sequence. each mutant was assayed for its ability to promote the translocation of giii across the endoplasmic reticulum membrane and the subsequent localization of the mature form of the glycoprotein to the infected cell surface or the virus ... | 1993 | 8385840 |
| protection against pseudorabies virus infection by intranasal vaccination of newborn pigs. | intranasal vaccination of newborn pigs with pseudorabies virus (prv) strain iowa s62/26 tk- gx- bgal+ was evaluated to determine whether protective immunity could be stimulated in pigs given colostrum from immune sows. three litters were vaccinated (2 litters from prv-immune sows and 1 born to a prv-free sow), and 2 were left as nonvaccinated controls (1 passively immune and 1 prv-nonimmune). pigs were then challenge-exposed at 15 weeks of age with virulent prv strain 4892. vaccinated pigs that ... | 1993 | 8387249 |
| direct isolation and identification of recombinant pseudorabies virus strains from tissues of experimentally co-infected swine. | tissue homogenates were obtained from swine co-infected with 2 vaccine strains of pseudorabies virus (prv). viral isolates derived by serial plaque purification directly from tissue homogenates, without an intervening step of isolation and amplification on cell cultures, were characterized as recombinant and parental prv genotypes on the basis of thymidine kinase and glycoprotein x gene combinations. use of limiting dilutions and recovery of virus isolates as individual plaques minimized the lik ... | 1993 | 8387251 |
| specific pseudorabies virus infection of the rat visual system requires both gi and gp63 glycoproteins. | transneuronal transport of pseudorabies virus (prv) from the retina to visual centers that mediate visual discrimination and reflexes requires specific genes in the unique short region of the prv genome. in contrast, these same viral genes are not required to infect retinorecipient areas of the brain involved in circadian rhythm regulation. in this report, we demonstrate that viral mutants carrying defined deletions of the genes encoding glycoprotein gi or gp63, or both, result in the same drama ... | 1993 | 8389905 |
| species selective interaction of alphaherpesvirinae with the "unspecific" immune system of the host. | during evolution herpesviridae have developed glycoproteins, which interact with essential components of the immune system. besides immunoglobulin-binding proteins (= fc-receptors), expressed by several members of the herpesfamily, the interaction with the complement system plays a role in the pathogenicity of herpes simplex virus. here we report that the ability to interact with the third complement component (c3), the central mediator of complement activation, was also found among several anim ... | 1993 | 8390825 |
| involvement of membrane-bound viral glycoproteins in adhesion of pseudorabies virus-infected cells. | cell-associated spread of pseudorabies virus (prv) plays an important role in the pathogenesis of the disease. besides the already known direct cell-to-cell spread of the virus in monolayers, adhesion and subsequent fusion of suspended prv infected cells to monolayers of uninfected cells are thought to occur. to study the adhesion of prv-infected cells, an in vitro model was developed in sk-6 cells. specific adhesion of prv-infected cells to an uninfected monolayer started 5 h after infection of ... | 1993 | 8392594 |
| deleting valine-125 and cysteine-126 in glycoprotein gi of pseudorabies virus strain nia-3 decreases plaque size and reduces virulence in mice. | we investigated the function of antigenic domains on gi in virulence and immunogenicity. three prv gi mutants were constructed by deleting nucleotides coding for the following amino acids: valine-125 and cysteine-126, located in a discontinuous antigenic domain (m 303); glycine-59 and aspartic acid-60 located in a continuous antigenic domain (m304); and arginine-67 and alanine-68, located in a discontinuous antigenic domain (m305). mismatch primers in the polymerase chain reaction were used to i ... | 1993 | 8394068 |
| prevalence of pseudorabies (aujeszky's disease) virus antibodies in feral swine in florida. | serum samples collected from feral swine (sus scrofa) throughout florida (usa) from 1980 to 1989 were tested for antibodies to pseudorabies virus (prv) by the serum neutralization test, the latex agglutination test, or by the enzyme-linked immunosorbent assay. seropositive swine were detected at 11 of 13 sites with a composite seroprevalence of 34.8% (579 of 1,662 samples; range = 5.9% to 58.2%) for sites with seropositive swine. data on age and sex of the swine were available from three sites. ... | 1993 | 8394943 |
| comparison of the protective efficacy of aujeszky's disease (pseudorabies) virus glycoproteins obtained from different sources. | the immunogenic properties of a series of glycoprotein preparations are compared using inactivated conventional vaccines as reference. serological response and protective efficacy of vaccination of mice and pigs are evaluated for glycoprotein immunogens obtained from various sources. bhk-21 cell cultures were infected with aujeszky's disease virus and used as antigenic source. glycoproteins were obtained from (i) the whole culture (ii) the cell sediment and (iii) the clarified supernatant. both ... | 1993 | 8395745 |
| immunohistological study of encephalomalacia in pigs infected with aujeszky's disease virus. | seven hysterectomy-derived colostrum-deprived pigs aged 4 weeks were inoculated intranasally with 10(3) plaque-forming units (1 ml) of the yamagata ys-81 strain of aujeszky's disease virus. one pig died and five developed encephalomyelitis and trigeminal ganglionitis. three pigs killed on days 12-16 showed prominent malacic degeneration. associated with the malacic foci were many lysosome-positive cells. igg- and igm-containing cells in the perivascular cuffs and glial nodules were first detecte ... | 1993 | 8396159 |
| diagnostic compatibility of a thymidine kinase, inverted repeat, gi, and gpx modified live gene-deleted prv vaccine with three differential elisas. | the differential pseudorabies virus (prv) vaccines currently in use in the usa have deletions of the genes coding for the glycoprotein i (gi) and/or glycoprotein x (gpx). the absence of gi and/or gpx allow for the serologic differentiation of vaccinated swine from prv-infected swine using differential enzyme-linked immunosorbent assays (elisas). a newly developed pseudorabies vaccine virus has 4 deletions of the viral genome: the genes coding for gi, gpx, and thymidine kinase and a portion of th ... | 1993 | 8396984 |
| application of the polymerase chain reaction (pcr) in veterinary diagnostic virology. | the polymerase chain reaction has become an important diagnostic tool for the veterinary virologist. conventional methods for detecting viral diseases can be laborious or ineffective. in many cases pcr can provide a rapid and accurate test. in this article we explain the basic principles of pcr and supply a reference list of its uses in diagnostic veterinary virology. | 1993 | 8396281 |
| lack of stereospecificity of suid pseudorabies virus thymidine kinase. | we have partially purified suid pseudorabies virus (prv) thymidine kinase from infected thymidine kinase- mouse cells, and cytosolic swine thymidine kinase from lymphatic glands, and we have found that prv thymidine kinase, unlike the host enzyme, shows no stereospecificity for d- and l-beta-nucleosides. in vitro, unnatural l-enantiomers, except l-deoxycytidine, function as specific inhibitors for the viral enzyme in the order: l-thymidine >> l-deoxyguanosine > l-deoxyuridine > l-deoxyadenosine. ... | 1993 | 8396911 |
| evaluation of the safety and efficacy of a thymidine kinase, inverted repeat, gi, and gpx gene-deleted pseudorabies vaccine. | a thymidine kinase (tk), inverted repeat, glycoprotein i (gi) and glycoprotein x (gpx) gene-deleted modified live virus pseudorabies vaccine was evaluated for safety in swine and for efficacy in protecting swine against challenge with pseudorabies virus (prv). safety was evaluated by inoculating pregnant gilts intravenously and 3-day-old pigs intracerebrally with the vaccine. efficacy was evaluated by 1) vaccinating 3-day-old pigs with a minimal protective dose intranasally and then challenging ... | 1993 | 8396983 |
| experimental pneumonia of pigs infected with aujeszky's disease virus and actinobacillus pleuropneumoniae. | experimental infections were induced out to examine whether aujeszky's disease virus (adv) infection in pigs results in a severe pneumonia by actinobacillus pleuropneumoniae. intranasal inoculation of adv (10(6.9) median tissue culture infective dose/head) in 4-month-old primary specific-pathogen-free pigs was followed by the inoculation of a. pleuropneumoniae type 1 (10(3.1) or 10(5.1) colony-forming-units/head). the pigs inoculated with adv alone developed clinical signs of aujeszky's disease ... | 1993 | 8399736 |
| characterization of the pseudorabies virus-specific immunoglobulin m response and evaluation of its diagnostic use in pigs with preexisting immunity to the virus. | despite preexisting immunity to pseudorabies virus (prv), pigs may become infected and may or may not show clinical signs of disease. to investigate whether detection of immunoglobulin m (igm) antibodies to prv is suitable for diagnosis of recent infection in pigs with (or without) preexisting immunity, the igm responses of pigs were examined after both experimental and natural infections. upon inoculation of seronegative pigs with a low dose of a mildly virulent strain of prv, igm was first det ... | 1993 | 8408547 |
| a quantitative technique for the study of the latency of aujeszky virus. | latency represents a challenge for any herpesvirus vaccine. vaccines could differ in their ability to minimize latency of pseudorabies virus (prv). to study this possibility, a quantitative and differential prv-specific polymerase chain reaction (pcr) was developed by the authors. efficiency of amplification in different tubes is measured by co-amplification with the viral targets (either gi or gp50 genes) of the porcine gene nuclear factor 1. the criteria used to select this approach to a quant ... | 1993 | 8400390 |
| antibody prevalence of hog cholera, bovine viral diarrhoea and aujeszky's disease virus in wild boars in northern germany. | during the hunting season 1990/1991 a total of 841 blood samples was collected from shot wild boar corresponding to about 2.11% of the total hunting bag in lower saxony. all the sera were screened for neutralizing antibodies (nab) to hog cholera virus (hcv) and bovine viral diarrhoea virus (bvdv) by direct neutralizing peroxidase linked antibody (npla) assay. for the detection of antibodies (ab) against hcv a complex trapping blocking (ctb) elisa was used. cytotoxic sera were retested using an i ... | 1993 | 8404524 |
| progress after one year of a pseudorabies eradication program for large swine herds. | six large farrow-to-finish swine herds quarantined for pseudorabies in illinois participated in the usda-initiated large herd cleanup study. these herds were monitored for antibodies to pseudorabies virus (prv) for 1 year after the initiation of an intensive eradication program. herd size ranged between 425 and 1,500 females of breeding age. gene-deleted modified-live virus vaccines were used on all farms, with 3 of the 6 herds receiving a vaccine with a deletion of the gene for glycoprotein-i a ... | 1993 | 8407443 |
| deleting two amino acids in glycoprotein gi of pseudorabies virus decreases virulence and neurotropism for pigs, but does not affect immunogenicity. | the virulence, pathogenicity and immunogenicity of two pseudorabies virus (prv) variants were investigated in 3-week-old pigs that had been intranasally infected. variant m303 (delta 125,126) lacked amino acids valine (125) and cysteine(126) in an immunodominant antigenic region of glycoprotein i (gi) containing two discontinuous antigenic domains, whereas m304 (delta 59,60) lacked amino acids glycine(59) and aspartic acid(60) in a continuous antigenic domain. m303 (delta 125,126) was not virule ... | 1993 | 8409943 |
| cellular immune response to hog cholera virus (hcv): t cells of immune pigs proliferate in vitro upon stimulation with live hcv, but the e1 envelope glycoprotein is not a major t-cell antigen. | t-cell responses of pigs to hog cholera virus (hcv) have reportedly been absent or difficult to detect. therefore, little is known about cellular immunity to hcv. in this study, we used an attenuated strain of pseudorabies virus expressing the envelope glycoprotein e1 of hcv and purified recombinant e1 to examine whether the e1 protein is a target antigen recognized by the t cells of hcv-immune pigs. we were unable to identify the e1 protein as a major target antigen recognized by the t cells of ... | 1993 | 8474180 |
| prophylactic application of propionibacterium avidum kp-40 in swine with acute experimental infections. i. viral infections--aujeszky's disease and classical swine fever. | the usefulness of the prophylactic application of propionibacterium avidum kp-40 (pa), a potent stimulator of the macrophage-monocyte system and inducer of endogenous interferons, was demonstrated in swine infected experimentally with aujeszky's disease or classical swine fever viruses. some of the infected animals were preimmunized with respective vaccines containing live, attenuated viruses. in vaccinated and non-vaccinated swine infected with aujeszky's disease virus, pretreatment with pa low ... | 1993 | 8486091 |
| estimating sample sizes for a two-stage sampling survey of seroprevalence of pseudorabies virus (prv)-infected swine at a regional level in the netherlands. | in the european union, vaccination campaigns against pseudorabies virus (prv) in swine have been started to eradicate prv. specific sampling designs are needed to monitor prv seroprevalence at a regional level. this paper demonstrates how sampling theory can be applied to design a disease seroprevalence survey, using prv as an example. in the spring of 1994, the four regions in the netherlands covered by the regional animal health services were monitored with respect to prv seroprevalence. per r ... | 1995 | 8525602 |
| comparison of freund's adjuvant and titermax in inducing anti-idiotype to idiotypic antibodies against pseudorabies virus antigens. | freund's adjuvant (fa) and titermax (tm) were compared for their effectiveness in the induction of the anti-idiotypic antibodies (anti-id or ab2) in pigs, goats and mice against swine polyclonal anti-pseudorabies virus (prv) antibodies (ab1) by sequential immunization procedures. both adjuvants had similar effects on inducing anti-swine immunoglobulin antibodies in the animals. however, high levels of the anti-id were only generated in animals that received fa. serological characterization of th ... | 1995 | 8533307 |
| transneuronal spread of the pseudorabies virus after injection into the central nucleus of the amygdala in the rat. | the pseudorabies virus (prv) is a swine alpha herpes virus that is widely used as a neural tracer because of its marked neurotropism and transneuronal transmissibility (card et al., 1991, 1992; strack and loewy 1990). prv has been used to retrogradely identify spinal cord and brainstem connections to various peripheral organs, but few anatomical studies have used cns inoculation of prv to investigate intrinsic brain connectivity. improved knowledge of the mode and temporal pattern of transneuron ... | 1994 | 8542420 |
| study of immune function in inbred miniature pigs vaccinated and challenged with suid herpesvirus 1. | specific immune responses of inbred miniature pigs following vaccination and challenge with suid herpesvirus 1 (shv-1) were determined. vaccination of swine with shv-1 elicited both specific neutralizing antibody and lymphoproliferative responses. moreover, pigs vaccinated with shv-1 were fully protected against a lethal virus challenge. pigs vaccinated with a recombinant (r) shv-1 virus, followed by challenge with a virulent shv-1, had lower percentages of circulating t- and b-lymphocytes, and ... | 1995 | 8548690 |
| epitope-specific antibody response against glycoprotein e of pseudorabies virus. | in this study we investigated the epitope-specific antibody response against glycoprotein e (ge) of pseudorabies virus. epitope-specific antibody responses were investigated by enzyme-linked immunoperoxidase monolayer assays. in a vaccinated crossbred pig population, most pigs responded to antigenic domain e and to a lesser degree to antigenic domains c and d. only few pigs responded to antigenic domains f, a, and b. using vaccinated pigs, we investigated the influence of two different pseudorab ... | 1994 | 8556492 |
| development and antigen specificity of the lymphoproliferation responses of pigs to pseudorabies virus: dichotomy between secondary b- and t-cell responses. | to better understand the contribution of t cells to the immunity of pigs to pseudorabies virus (prv), we examined the lymphoproliferation response to this virus. depletion studies demonstrated that both cd2+cd8+ and cd2+cd4+ cells contributed to lymphoproliferation, but to varying degrees upon stimulation with live and ultraviolet (uv) light-inactivated prv. flow cytometric analysis revealed the emergence of both cd2+cd8+ and cd2+cd4+ lymphoblastoid cells. to examine the contribution of specific ... | 1995 | 8550073 |
| benefit-cost analysis of the national pseudorabies virus eradication program. | an epidemiologic model of pseudorabies virus (prv) in swine was developed. this model was used to project future herd-to-herd disease transmission under alternative eradication or control programs over 20 years (1993 to 2012). with current prv eradication program funding, it was projected that prevalence would be 23% in higher-risk states in the united states, 10% in moderate-risk states, and 1% in lower-risk states. increased funding for the prv eradication program was projected to reduce prv p ... | 1996 | 8567375 |
| gastrointestinal and skin lesions in piglets naturally infected with pseudorabies virus. | pseudorabies virus (prv) infection was diagnosed in 4 piglets from a litter by immunohistopathologic examination and virus isolation. three piglets had moderate to severe neuronal degeneration, and prv antigen was detected in auerbach's myenteric plexus and meissner's submucosal plexus of the gastrointestinal tract. one piglet had 2 types of skin lesions. one lesion appeared on the hip and ear and was characterized by ballooning degeneration, necrosis of epithelial cells, and intranuclear inclus ... | 1995 | 8580164 |
| [diagnosis of contagious diseases in animals using pcr]. | the pcr is used for diagnostic purposes as it allows to detect infections agents within a much shorter time than by cultural isolation. in addition, it can detect non-infectious viruses and bacteria in clinical samples. these advantages are important factors in the diagnosis of highly contagious animal diseases (mainly caused by viruses) since a rapid laboratory diagnosis will allow to take immediate disease control actions. pcr is routinely used at the institute of african and classical swine f ... | 1995 | 8584867 |
| [progress in the development of vaccines against aujeszky's disease]. | new insights into the molecular biology of pseudorabies virus (prv), the causative agent of aujeszky's disease (ad) of pigs, led to novel concepts for eradication of the disease. virus mutants, which lack certain nonessential glycoproteins, formed the basis for the development of the first available marked vaccines. they allow a differentiation between infected and vaccinated animals. further molecular studies resulted in the identification of several prv genes whose products modulate virulence ... | 1995 | 8585074 |
| the receptor-binding domain of pseudorabies virus glycoprotein gc is composed of multiple discrete units that are functionally redundant. | many herpesviruses attach to cells in a two-step process, using the glycoprotein gc family of homologs to bind the primary receptor, heparan sulfate (hs) proteoglycan, and glycoprotein gd homologs to bind an unknown secondary receptor. we have previously shown by deletion analysis that the amino-terminal one-third of gc from pseudorabies virus (prv), a swine herpesvirus, includes at least the principal hs receptor-binding domain. this portion of prv gc contains three discrete clusters of basic r ... | 1996 | 8627651 |
| cell-mediated immunity to pseudorabies virus: cytolytic effector cells with characteristics of lymphokine-activated killer cells lyse virus-infected and glycoprotein gb- and gc-transfected l14 cells. | we examined cytolytic cells that lyse pseudorabies virus (prv)-infected cells in pigs. in vitro stimulation of peripheral blood mononuclear cells from prv-immune pigs with live prv generated cells that lysed prv-infected immortalized b cells. several lines of evidence indicated a major contribution of non-major histocompatibility complex (mhc)-restricted cytolytic cells, which displayed characteristics of natural killer (nk) or lymphokine-activated killer cells: cytolysis was non-mhc-restricted, ... | 1996 | 8609496 |
| mode of interaction between pseudorabies virus and heparan sulfate/heparin. | it has been demonstrated that the efficient attachment of pseudorabies virus (prv) is mediated by an interaction between glycoprotein c (gc) and a cellular heparin-like substance (t. c. mettenleiter, l. zsak, f. zuckermann, n. sugg, h. kern, and t. ben-porat, j. virol. 64, 278-286, 1990). according to the prevalent concept, this interaction is likely to occur between clusters of basic residues of prv gc and the negatively charged sulfate esters and carboxylate groups of heparan sulfate/heparin. ... | 1996 | 8615039 |
| acetylcholine activates latent pseudorabies virus in pigs. | pseudorabies virus (prv) was isolated from the nasal swabs and the cultured trigeminal ganglia of latently infected pigs after they were treated with acetylcholine (ach). these results indicate that ach activates latent infections of prv. | 1996 | 8629944 |
| functional characterization of porcine cd4+cd8+ extrathymic t lymphocytes. | the porcine immune system is unique in that the expression of cd4 and cd8 antigens defines four subpopulations of resting, extrathymic (cd1-) t lymphocytes. in addition to cd4-cd8+ and cd4+cd8- t lymphocytes, cd4-cd8- and cd4+cd8+ lymphocyte subpopulations are prominent in blood as well as in lymphoid tissues. in the present study, a functional comparison was made between cd4+cd8- and cd4+cd8+ t lymphocyte subpopulations. in a primary in vitro immune response against alloantigenic stimulator cel ... | 1996 | 8640877 |
| identification of cell surface molecules that interact with pseudorabies virus. | the alphaherpesvirus pseudorabies virus (prv) has been shown to attach to cells by interaction between the viral glycoprotein gc and cell membrane proteoglycans carrying heparan sulfate chains (hspgs). a secondary binding step requires gd and presumably another, hitherto unidentified cellular receptor. by use of a virus overlay protein binding assay (vopba), cosedimentation analyses, and affinity chromatography, we identified three species of cell membrane constituents that bind prv. by treatmen ... | 1996 | 8642635 |
| glycoprotein d-negative pseudorabies virus can spread transneuronally via direct neuron-to-neuron transmission in its natural host, the pig, but not after additional inactivation of ge or gi. | envelope glycoprotein d (gd) is essential for entry of pseudorabies virus (prv) into cells but is not required for the subsequent steps in virus replication. phenotypically complemented gd mutants can infect cells and can spread, both in vitro and in mice, by direct cell-to-cell transmission. progeny virions released by infected cells are noninfectious because they lack gd. the aim of this study was to determine the role of gd in the neuropathogenicity of prv in its natural host, the pig. we inv ... | 1996 | 8642642 |
| the use of marker vaccines in eradication of herpesviruses. | marker vaccines are vaccines that allow serological differentiation between infected and vaccinated individuals. this differentiation is based on the absence of one or more microbial proteins in the vaccine that are present in the wild-type micro-organism. consequently, after infection, but not after vaccination, an antibody response against that specific protein(s) can be detected. with a protein-specific antibody test infected individuals can thus be distinguished from vaccinated individuals. ... | 1996 | 8717389 |
| transmission of two pseudorabies virus strains that differ in virulence and virus excretion in groups of vaccinated pigs. | to determine whether 2 pseudorabies virus (prv) strains that differ in virulence differ in transmission among vaccine strain 783-inoculated pigs. | 1996 | 8720236 |
| experimental quantification of transmission of genetically engineered pseudorabies virus. | there is concern that live pseudorabies virus (prv) vaccine or prv vector vaccine strains may spread from vaccinated to unvaccinated pigs. moreover, it is feared that recombining prv vaccine strains with related vaccine or wild-type strains may lead to spread and survival of recombinant prv. to learn more about to what extent different prv vaccine strains could spread we used a previously described experimental model to study the transmission of intranasally inoculated prv mutant strains under e ... | 1995 | 8701591 |
| infection of pigs by aerosols of aujeszky's disease virus and their shedding of the virus. | on three consecutive days, six pigs were exposed for 15 minutes to aerosols of aujeszky's disease virus. the total estimated dose was 4.5 log 10 tcid50. within each isolation room, a sentinel pig was placed on a deck two feet away from the infected pig. the breath of the pigs that had inhaled the aerosols was collected on days 3, 7 and 13. the respiratory and other clinical signs of the infected pigs resembled those in field cases of aujeszky's disease. all the pigs infected with aujeszky's dise ... | 1996 | 8735512 |
| comparison of the abilities of serologic tests to detect pseudorabies-infected pigs during the latent phase of infection. | to compare the sensitivities of all available serologic tests in detecting pseudorabies virus (prv) antibodies in pigs during long-term latent pseudorabies. | 1996 | 8723868 |
| pseudorabies virus eradication by area-wide vaccination is feasible. | this article reviews the rationale for using marker vaccines and companion diagnostic tests in the eradication of pseudorabies virus (prv). recent advances in vaccinology and epidemiology indicate that, despite the inability to induce complete immunity, vaccination is a useful tool in the battle against prv. this review focuses on the effectiveness of vaccination under field conditions and on herd, management and regional factors that are associated with prv introduction or transmission. | 1995 | 8751278 |
| functional and phenotypic analysis of porcine peripheral blood cd4/cd8 double-positive t cells. | functional and phenotypic properties of porcine peripheral blood cd4/cd8 double-positive (dp) lymphocytes were examined. in cross-sectional and longitudinal studies involving a total of 103 pigs, this lymphocyte population was found to increase gradually in proportion with age, comprising < 2% of the total peripheral blood lymphocyte pool in 1-week-old swine and reaching 30-55% by 3 years of age. cd4/cd8 dp lymphocytes were able to proliferate in response to stimulation with recall viral antigen ... | 1996 | 8778040 |
| marked reduction of the prevalence of pseudorabies virus-infected pigs in pig dense regions of the netherlands during the first year of a nation-wide vaccination campaign. | the breeding and finishing pig populations in four animal health service regions in the netherlands were monitored with respect to pseudorabies virus (prv) seroprevalence. analysis of data of the seroprevalence survey of 1994 indicated that two samples per herd was sufficient to estimate the seroprevalence in both the sow and finishing pig populations. in the northern, eastern, southern, and western regions, 115, 645, 940, and 218 sow herds and 114, 1036, 954, and 323 pig finishing herds were sa ... | 1996 | 8792598 |
| replication and pathogenicity after intranasal and intracranial inoculation of swine with a recombinant pseudorabies virus containing a deletion at the ul/ir junction. | pseudorabies virus (prv) is a neurotropic herpesvirus of swine. previously, we described construction of a recombinant strain of prv (llt beta delta 2) which contains a 3.0-kb deletion spanning the junction of the unique long and internal repeat sequences. compared to the parental strain, indiana-funkhauser, and a virus rescued for the deleted sequences (llt beta res), llt beta delta 2 replicated efficiently at the site of inoculation, yet exhibited significantly reduced virulence when inoculate ... | 1996 | 8806536 |
| comparison of the protective efficacy of recombinant pseudorabies viruses against pseudorabies and classical swine fever in pigs; influence of different promoters on gene expression and on protection. | the glycoprotein e (ge) locus in the genome of pseudorabies virus (prv) was used as an insertion site for the expression of glycoprotein e1 of classical swine fever virus (csfv). transcription of e1 in the recombinants m401, m402 or m403 was regulated by the gd promoter of prv, the immediate early gene promoter of human cytomegalovirus, or the ge promoter of prv, respectively. groups of four pigs were vaccinated once intramuscularly with 10(6) plaque forming units (p.f.u.) of the recombinant vir ... | 1996 | 8821642 |
| genetic immunization of seronegative one-day-old piglets against pseudorabies induces neutralizing antibodies but not protection and is ineffective in piglets from immune dams. | immune response inhibition by maternal antibodies is a major impediment to the vaccination of the young born to immune dams. this study explored the efficiency of genetic immunization of the neonates at bypassing this inhibition, by testing the muscular inoculation of the gd glycoprotein gene of pseudorabies virus (prv) in piglets. plasmid dna (400 micrograms) was inoculated in four groups of one-day-old piglets, from sows vaccinated or not against prv. half of the groups received a booster inje ... | 1996 | 8822614 |
| pathologic changes in closed porcine intestinal loops inoculated with aujeszky's disease virus. | development of enteric lesions in closed jejunal and ileal loops inoculated with aujeszky's disease virus (adv) was examined in four 6-week-old spf pigs. a large number of adv antigens were detected first in necrotic foci in the subepithelial areas, and subsequently in the epithelial cells, lymphoid follicles in peyer's patches and neuronal cells of meissner's and auerbach's plexuses. | 1996 | 8877987 |
| no major outbreaks of pseudorabies virus in well-immunized sow herds. | in this study we quantified the transmission of pseudorabies virus (prv) in well-immunized sow herds in the netherlands. in three herds, sows were tested for antibodies to ge of prv every time after they had been transported to another barn (survey a). in 99 other herds, sows were tested simultaneously once or twice yearly (survey b). we observed six introductions in survey a and 53 in survey b. none of these introductions resulted in extensive spread of the virus. the reproduction ratio r, whic ... | 1996 | 8879100 |
| a fluorescence-based quantitative pcr method for investigation of pseudorabies virus latency. | a quantitative pcr method was developed in order to quantitate the number of copies of pseudorabies virus (prv) genome present in tissues from infected pigs. the method is based on the use of an internal standard that differs from the target dna by a deletion of ten base pairs, and that is co-amplified with the target dna. the resulting pcr products are labelled with a fluorescent primer and are then separated and detected by means of an automated sequencer. the assay was found to be specific an ... | 1996 | 8882940 |
| comparison of the protective response induced by nyvac vaccinia recombinants expressing either gp50 or gii and gp50 of pseudorabies virus. | a nyvac vaccinia vector containing genes for pseudorables virus glycoproteins gii and gp50 was administered to pigs to determine if it would have a greater protective effect than a vector containing the gene for gp50 alone. both nyvac vectors protected pigs similarly from virulent pseudorabies virus challenge. | 1996 | 8904669 |
| synthesis, processing, and oligomerization of bovine herpesvirus 1 ge and gi membrane proteins. | this study reports the identification and initial characterization of the precursors, modified forms, and oligomers of bovine herpesvirus 1 (bhv-1) gi and ge proteins with polyvalent rabbit serum specific for gi or ge. our experiments used the colorado strain of bhv-1 and mutant viruses with insertions of the escherichia coli lacz gene into the predicted ge and gi reading frames. we also translated the ge and gi open reading frames in vitro and expressed them in uninfected cells using eukaryotic ... | 1996 | 8892910 |
| spatial and temporal epidemiology of pseudorabies virus infection. | to examine the pattern of pseudorabies virus (prv) infection in pennsylvania and identify the area factors associated with herd quarantine status. | 1996 | 8915430 |
| lack of serum antibodies against glycoprotein e in pseudorabies virus-immune pigs infected with wild-type virus. | to examine whether pigs with solid immunity against pseudorabies virus (prv) could harbor latent infection with wild-type prv without developing antibodies against glycoprotein e (ge), which is used as a marker protein to differentiate pigs that have been vaccinated from pigs infected with wild-type prv. | 1996 | 8915423 |
| a double-strand break in a herpesvirus genome stimulates targeted homologous recombination with exogenous, cloned viral sequences. | a method is described for the highly efficient recovery of recombinant pseudorabies virions; the approach should be applicable to other herpesviruses. pseudorabies virus (prv) strain prv509 contains a unique ecori site in its genome, largely replacing the glycoprotein gc gene. by digesting prv509 dna with ecori prior to cotransfection with plasmid dna that harbored a cloned copy of gc, we isolated recombinant viruses containing the cloned gc allele at a frequency exceeding 75%. this represented ... | 1996 | 8919827 |
| evaluation of nucleic acid amplification methods for the detection of hog cholera virus. | a blind panel was tested in a diagnostic evaluation of a reverse transcription (rt) polymerase chain reaction (pcr) method for detecting hog cholera virus (hcv) from pig tissues. the capability of the rt-pcr test to discriminate between hcv and related pestiviruses, bovine viral diarrhea virus (bvdv), and those viruses causing similar diseases in swine, including african swine fever virus (asfv) and pseudorabies virus (prv), was also considered. nucleic acid extraction involved either kit-based ... | 1996 | 8953524 |
| acute outbreak of porcine parvovirus infection in mozambique. | investigations were made to determine the causal agent of an acute outbreak of abortions recorded in a swine herd in mozambique. isolation of porcine parvovirus and demonstration of its specific antibodies accomplished by using enzyme-linked immunosorbent assay, haemagglutination inhibition and immunofluorescent tests, indicated that porcine parvovirus was the causal agent of the abortions. other pathogenic agents causing reproductive failure, e.g. pseudorabies virus, leptospira or brucella spec ... | 1995 | 8966762 |
| assessment of the quality of tests for the detection of antibodies to aujeszky's disease virus glycoprotein ge in a target population by the use of receiver operating characteristic curves. | the performance of tests for the detection of antibodies to aujeszky's disease virus glycoprotein e (ge) in a target population was evaluated by constructing and analysing receiver operating characteristic (roc) curves. these curves assess the discriminating ability of a test over the entire range of test signals. the advantages of applying the analysis to a sample of the target population (all commercial pigs in the netherlands), as compared to using a panel of test sera, are that the estimates ... | 1996 | 8938859 |
| detection of lymphoproliferative responses against pseudorabies virus immediate early protein (ie180) in swine immunized with a modified live virus vaccine. | the immediate early protein (ie180) of pseudorabies virus (prv) was generated by cycloheximide (chx) reversal procedures in prv-infected swine skin cells. using this ie180 preparation as antigen, specific proliferation was detected in mononuclear cells (pbmncs) from swine vaccinated with a modified live virus (mlv) prv vaccine. two sets of data support this conclusion. (a) pbmncs of c/csla inbred swine vaccinated with an mlv vaccine a year before the test exhibited significant responses against ... | 1996 | 8978021 |
| immunobiology of pseudorabies (aujeszky's disease). | aujeszky's disease (ad), a serious illness of pigs causing significant economic losses in the pig industry, is caused by pseudorabies virus (prv). prv belongs to the alphaherpesvirus subfamily of the herpesviruses with a double-stranded dna genome in an enveloped capsid capable of encoding approximately 70 proteins. for disease control, vaccination with live and killed vaccines is performed. recently, 'marked' vaccines have become available for use in eradication programs based on the differenti ... | 1996 | 8988868 |
| effect of vaccination against aujeszky's disease compared with test and slaughter programme: epidemiological and economical evaluations. | in january 1990, a 6-year program was initiated to eliminate endemic aujeszky's disease virus (adv) infection from the pig herds in an area of northern germany, bordering southern denmark, with intensive pig farming. in the first 3 years of the campaign, an intensive compulsory vaccination program, with glycoprotein i (gi)-deleted vaccines, of all pigs in the area was employed. beginning in june 1990 and for the first 3 years of the project, approximately 200 herds randomly selected from all her ... | 1996 | 8996885 |
| negative regulation of immediate-early gene expression of pseudorabies virus by interferon-alpha. | pseudorabies rabies (prv) replication in vero cells was suppressed by treatment with human natural interferon-alpha (ifn-alpha). messenger rna transcribed from the prv immediate-early (ie) gene was reduced in the ifn-alpha-treated cells. transient expression assays showed that transcription from the prv ie promoter was selectively inhibited in the ifn-alpha-treated cells. analysis of deletion mutants of the prv ie promoter sequence suggested that at least one element between the transcription in ... | 1996 | 9008338 |
| latency characteristics of an epo and llt mutant of pseudorabies virus. | | 1996 | 9026066 |
| a pseudorabies virus mutant with deletions in the latency and early protein o genes: replication, virulence, and immunity in neonatal piglets. | the pathogenicity of a double mutant of pseudorabies virus (prv) with deletions in the latency gene and the early protein o gene was examined. in comparison to the parent indiana-funkhauser virus, the ability of this mutant to replicate and to cause disease in piglets is greatly reduced. at an infection dose that caused no clinical signs in 5-day-old neonatal piglets, this mutant was capable of eliciting solid protective immunity against a lethal prv challenge. thus, the double-gene deletion att ... | 1996 | 9026076 |
| comparison of two pseudorabies virus vaccines, that differ in capacity to reduce virus excretion after a challenge infection, in their capacity of reducing transmission of pseudorabies virus. | pseudorabies virus (prv) vaccines are often compared for their capacity to reduce virus excretion after a challenge infection. vaccines, used for the eradication of prv, however, should reduce transmission of prv among pigs. the purpose of this study was to investigate whether the amount of virus excreted after a challenge infection is an accurate measure of the capacity of a vaccine to reduce transmission of prv among pigs. two experiments were carried out, each using two groups of 10 pigs. the ... | 1997 | 9057255 |
| antiviral activity of crude extracts of guarea guidona. | crude extracts of leaves and fruits of guarea guidona were tested for antiviral activity against pseudorabies virus and foot-and-mouth disease virus in the ib-rs-2 pig cell line and against bovine herpesvirus-1 (bhv-1) in the gbk bovine cell line. the highest nontoxic doses of extracts from fruits and leaves were 125 micrograms/ml and 500 micrograms/ml. respectively. crude extracts presented antiviral activity against pseudorabies virus with a decrease in virus titer of 3.0 log units at 500 micr ... | 1996 | 9033817 |
| the us3-encoded protein kinase from pseudorabies virus affects egress of virions from the nucleus. | we examined the influence of inactivation of various genes located in the unique short (u(s)) region of pseudorabies virus on virus replication and assembly in porcine nasal mucosa explant cultures. the following strains were used: the virulent wild-type strain nia-3, and strains derived from nia-3 containing a mutation inactivating the genes encoding either the us3-encoded protein kinase (pk), gg, gd, gi, ge, the 28 kda ('28k') protein (single mutant), or the 28k and 11 kda ('11k') proteins (do ... | 1995 | 9049392 |
| discrete cleavage patterns of pseudorabies virus immediate early protein (ie180) seen in some cell lines upon extraction after cycloheximide reversal. | pseudorabies virus (prv) encodes for a single and essential immediate early phosphoprotein designated ie180. in this study, ie180 was examined in lysates from various cell lines infected at high multiplicities under cycloheximide inhibition of protein synthesis and subsequent reversal. three distinct protein patterns of ie180 which were cell-specific and dependant on the extraction procedure were revealed. detergent lysates of prv infected mdbk cells yielded almost exclusively wild type ie molec ... | 1997 | 9079763 |