| prrs syndrome in quebec: isolation of a virus serologically related to lelystad virus. | | 1992 | 1314445 |
| report on the first outbreaks of the porcine reproductive and respiratory syndrome (prrs) in france. diagnosis and viral isolation. | we describe the first known occurrence in france of the porcine reproductive and respiratory syndrome (prrs), a new porcine disease that first appeared in germany in november 1990. outbreaks of the disease appeared in november 1991 in brittany (france), with comparable clinical features to those observed in other countries, were definitively confirmed by a serological analysis from the affected animals using an immunoperoxidase monolayer assay with prrs-virus infected alveolar macrophages. furth ... | 1992 | 1319124 |
| [epidemic late abortion in swine--status of research]. | this article briefly describes the prrs (porcine reproductive and respiratory syndrome), which arose in the winter of 1990 in germany and other european countries. the data are accumulated from the literature and own experiences. the clinical picture of this new disease, which led to important economical losses is dominated by 1. an increased rate of reduced length of pregnancy with late abortion before day 110 or an increased length of pregnancy; 2. an increase of stillborn piglets; 3. a larger ... | 1992 | 1412430 |
| lelystad virus, the cause of porcine epidemic abortion and respiratory syndrome: a review of mystery swine disease research at lelystad. | this paper reviews the laboratory investigations that led us to isolate the lelystad virus and demonstrate that this virus causes mystery swine disease. we describe: 1) isolating the virus from the disease; 2) characterizing the virus as a new enveloped rna virus; 3) reproducing the disease experimentally with the isolated lelystad virus; 4) isolating the virus from the experimentally induced disease. | 1992 | 1481355 |
| isolation of a lelystad virus-like agent from british pigs and scanning electron microscopy of infected macrophages. | six, one-week-old gnotobiotic piglets were inoculated with tissues or sera collected from field cases of porcine reproductive and respiratory syndrome. the piglets showed little or no illness, and two that were necropsied at 8 and 9 days post infection appeared grossly normal. however, a lelystad virus-like agent was isolated from most of the inoculated pigs using porcine alveolar macrophage cultures. seroconversion to the lelystad virus was observed and some animals developed microscopically de ... | 1992 | 1481357 |
| porcine epidemic abortion and respiratory syndrome (mystery swine disease). isolation in spain of the causative agent and experimental reproduction of the disease. | in march of 1991, a disease that affected pregnant sows and caused a high mortality in unweaned piglets was detected in spain. based on the clinical signs observed, mystery swine disease, which had been described recently in germany, holland and belgium, was suspected. from the samples obtained from the affected farm, a filtrable agent (0.22 micron) was isolated on cell culture. it produced cytopathic effects, its replication was intracytoplasmic, it was sensitive to chloroform, and cross-reacte ... | 1992 | 1481358 |
| antigenic comparison of lelystad virus and swine infertility and respiratory syndrome (sirs) virus. | this study reports the antigenic relatedness of isolates of lelystad virus collected in the netherlands, germany, and the united states. the binding of antibodies directed against these isolates was tested in a set of field sera collected during outbreaks of porcine epidemic abortion and respiratory syndrome in europe and outbreaks of swine infertility and respiratory syndrome (sirs) in north america. two sets of sera from pigs experimentally infected with lelystad virus or sirs virus were also ... | 1992 | 1616977 |
| mystery swine disease in the netherlands: the isolation of lelystad virus. | in early 1991, the dutch pig-industry was struck by the so-called mystery swine disease. large-scale laboratory investigations were undertaken to search for the etiological agent. we focused on isolating viruses and mycoplasmas, and we tested paired sera of affected sows for antibodies against ten known pig viruses. the mycoplasmas m. hyosynoviae, m. hyopneumoniae, and acholeplasma laidlawii, and the viruses encephalomyocarditis virus and porcine enterovirus types 2 and 7 were isolated from indi ... | 1991 | 1835211 |
| experimental reproduction of porcine epidemic abortion and respiratory syndrome (mystery swine disease) by infection with lelystad virus: koch's postulates fulfilled. | aerosol exposure of eight pregnant sows to cell-culture- propagated lelystad virus resulted in clinical signs characteristic of so-called mystery swine disease. after an incubation of 4-7 days, all sows were inappetant and listless for 6-9 days. two sows developed a transient red-blue discolouration of the ears ('abortus blauw' or blue ear disease) accompanied by abdominal respiration, and two had a fever for one day only. one sow aborted at 109 days of gestation. the other seven sows, farrowing ... | 1991 | 1949539 |
| pathological, ultrastructural, and immunohistochemical changes caused by lelystad virus in experimentally induced infections of mystery swine disease (synonym: porcine epidemic abortion and respiratory syndrome (pears)). | the pathogenicity and pathogenesis of lelystad virus was studied in six 6-day-old spf piglets. a third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. from day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. lelystad virus was re-is ... | 1991 | 1949540 |
| determination of the 5' end of the lactate dehydrogenase-elevating virus genome by two independent approaches. | we have determined the 5' end of the lactate dehydrogenase-elevating virus (ldv) genome (strain ldv-p) using two independent approaches. in one approach, methylmercuric hydroxide-denatured genomic rna was reverse-transcribed using as primer an oligonucleotide complementary to the 5' end of open reading frame (orf) 1a. the first-strand cdna was ligated with t4 rna ligase to an oligonucleotide of which the 3' end was blocked. the ligated product was amplified by pcr, cloned and sequenced. in the s ... | 1994 | 7512122 |
| direct detection of the porcine reproductive and respiratory syndrome (prrs) virus by reverse polymerase chain reaction (rt-pcr). | a method for direct detection of the porcine reproductive and respiratory syndrome (prrs) virus was developed, based on reverse transcription of the viral rna coupled to dna amplification by polymerase chain reaction. a set of primers was designed from lelystad virus sequence within orf 7 encoding nucleocapsid protein. from seven spanish field isolated strains the 312 bp amplified fragment was cloned and sequenced. alignment with lelystad virus sequence revealed a 96-97% homology. a maximum sens ... | 1994 | 7545931 |
| sequence analysis of open reading frames (orfs) 2 to 4 of a u.s. isolate of porcine reproductive and respiratory syndrome virus. | the sequence of orfs 2 to 4 of a u.s. isolate of porcine reproductive and respiratory syndrome virus (prrsv), atcc vr2385, was determined by analysis of a cdna lambda library. the cdna clones containing prrsv specific sequences were selected using a vr2385 orf 4 specific pcr probe and sequenced. the orfs 2, 3 and 4 overlapped each other and encoded polypeptides with predicted m(r) of 29.5 kda (orf 2), 28.7 kda (orf 3) and 19.5 kda (orf 4), respectively. no overlap was found between orfs 4 and 5, ... | 1995 | 7646363 |
| molecular analysis of the orfs 3 to 7 of porcine reproductive and respiratory syndrome virus, québec reference strain. | the cdna sequence of the 3'-terminal genomic region of the québec iaf-exp91 strain of porcine reproductive and respiratory syndrome virus (prrsv) was determined and compared to those of other reference strains from europe (lelystad virus) and us (atcc vr2385, mn-1b). the sequence (2834 nucleotides) which encompassed orfs 3 to 7 revealed extensive genomic variations between the québec strain and lelystad virus (lv), resulting from high number of base substitutions, additions and deletions. the or ... | 1995 | 7661693 |
| comparison of the structural protein coding sequences of the vr-2332 and lelystad virus strains of the prrs virus. | the 3'-portion of the genome of a u.s. isolate of the porcine reproductive and respiratory syndrome (prrs) virus, atccvr-2332, was cloned and sequenced. the resultant 3358 nucleotides contain 6 open reading frames (orfs) with homologies to orfs 2 through 7 of the european strain of the prrs virus and other members of the free-standing genus of arteriviruses. both vr-2332 and the european isolate (called the lelystad virus) have been identified as infectious agents responsible for the swine disea ... | 1995 | 7661696 |
| production, characterization and reactivity of monoclonal antibodies to porcine reproductive and respiratory syndrome virus. | this report describes the preparation of six monoclonal antibodies (mabs) raised against a british isolate of porcine reproductive and respiratory syndrome virus (prrsv), their characterization in terms of protein specificity and their reactivity with different prrs viruses from europe and the usa. radioimmunoprecipitation and western blotting studies of mab reactivity with proteins from cell lysates of infected cells and purified virus revealed that four of the six mabs (wbe1 and wbe4-6) precip ... | 1995 | 7782765 |
| detection of porcine reproductive and respiratory syndrome virus and efficient differentiation between canadian and european strains by reverse transcription and pcr amplification. | two sets of oligonucleotide primers (1008ps-1009pr and 1010pls-1011plr) were designed according to the sequence of the nucleocapsid protein (n) gene of quebec reference strain iaf-exp91 of porcine reproductive and respiratory syndrome virus (prrsv). the primers were used in reverse transcription and pcr (rt-pcr) experiments for detection of viral genomic rna either from infected porcine alveolar macrophages (pam) or tissues from experimentally infected specific-pathogen-free pigs. considering th ... | 1994 | 7814546 |
| characterization of proteins encoded by orfs 2 to 7 of lelystad virus. | the genome of lelystad virus (lv), a positive-strand rna virus, is 15 kb in length and contains 8 open reading frames (orfs) that encode putative viral proteins. orfs 2 to 7 were cloned in plasmids downstream of the sp6 rna polymerase promoter, and the translation of transcripts generated in vitro yielded proteins that could be immunoprecipitated with porcine anti-lv serum. synthetic polypeptides of 15 to 17 amino acids were selected from the amino acid sequences of orfs 2 to 7 and antipeptide s ... | 1995 | 7831770 |
| isolation and serological characterization of porcine reproductive and respiratory syndrome (prrs) viruses from pigs with reproductive and respiratory disorders in japan. | three porcine reproductive and respiratory syndrome viruses (prrsvs) were successfully isolated from stillborn piglets and fattening pigs derived from different herds affected either with an epizootic reproductive failure or a severe chronic respiratory distress in japan. the isolates were reacted with antisera against both european (lelystad virus) and american (strain 46448) prrsvs in indirect immunofluorescence (iif). however, cross immunoperoxidase monolayer assay revealed the close serologi ... | 1994 | 7865590 |
| analysis of simian hemorrhagic fever virus (shfv) subgenomic rnas, junction sequences, and 5' leader. | full-length simian hemorrhagic fever virus (shfv) genome rna (about 15 kb in length) and six subgenomic rnas, ranging in size from 0.65 to 4.7 kb, were detected by northern blot hybridization in ma104 cytoplasmic extracts with a 3' genomic antisense probe. the 5' regions of the two smallest subgenomic rnas (rnas 6 and 7) were cloned and sequenced. sequence analysis indicated that these two rnas contained a common 5' leader sequence joined to the subgenomic rna bodies via a highly conserved junct ... | 1995 | 7886957 |
| enzymatic amplification of lactate dehydrogenase-elevating virus. | to improve the detection of lactate dehydrogenase-elevating virus (ldv), we developed a pcr assay. primers were selected from orf7, encoding nucleocapsid protein vp1. no specific amplification was observed with any other common murine virus or with rnas from the closely related lelystad virus and equine arteritis virus. in experimentally infected mice, ldv could be detected in plasma in both the acute and the persistent phases. ldv was also detected by the pcr in contaminated pools of plasmodium ... | 1994 | 7989557 |
| molecular cloning and nucleotide sequencing of the 3'-terminal genomic rna of the porcine reproductive and respiratory syndrome virus. | the genomic rna of a porcine reproductive and respiratory syndrome virus (prrsv) isolate from the u.s.a., vr 2385 (atcc), was copied into cdna after priming with oligo(dt) and cloned into phage lambda. the cdna clones representing the 3'-terminal genomic rna of the virus were isolated and sequenced. the genome is a positive-stranded, polyadenylated rna with an estimated size of 15 kb. analysis of the resulting sequence identified three complete open reading frames (orfs) with the potential to en ... | 1994 | 8021610 |
| lelystad virus belongs to a new virus family, comprising lactate dehydrogenase-elevating virus, equine arteritis virus, and simian hemorrhagic fever virus. | lelystad virus (lv) is an enveloped positive-stranded rna virus, which causes abortions and respiratory disease in pigs. the complete nucleotide sequence of the genome of lv has been determined. this sequence is 15.1 kb in length and contains a poly(a) tail at the 3' end. open reading frames that might encode the viral replicases (orfs 1a and 1b), membrane-associated proteins (orfs 2 to 6) and the nucleocapsid protein (orf7) have been identified. sequence comparisons have indicated that lv is di ... | 1994 | 8032274 |
| uterine and placental alterations in pregnant sows associated with the porcine epidemic abortion and respiratory syndrome (pears). | in the winter of 1990/91 a new, economically devastating disease occurred in european pig breeding herds, characterized by late-term abortion, stillbirth and a high morbidity and mortality of suckling piglets. because of the clinical picture the disease was named porcine epidemic and respiratory syndrome (pears). in this study investigations were carried out in tissues of uterus and placentae of late gestational sows (107 to 112 days of gestation) in three different groups of animals: group i = ... | 1993 | 8237196 |
| lelystad virus and the porcine epidemic abortion and respiratory syndrome. | lelystad virus is the causal agent of a relatively new pig disease, variously known as mystery swine disease, porcine epidemic abortion and respiratory syndrome and porcine reproductive and respiratory syndrome. the virus is a small, enveloped rna virus, that tentatively can be included in a new virus family, the arteriviridae. the virus has infected pigs throughout the world and seems to persist in many pig populations and in individual pigs. clinical signs of an infection with lelystad virus a ... | 1993 | 8343802 |
| subgenomic rnas of lelystad virus contain a conserved leader-body junction sequence. | during the replication of lelystad virus in alveolar lung macrophages, a 3'-coterminal nested set of six subgenomic rnas (rna2 to rna7) is formed. these contain a common leader sequence derived from the 5' non-coding region of the genomic rna. in this study, the sequence of the junction sites, i.e. the sites where the leader sequence joins to the body of the subgenomic rna, was determined for all six subgenomic rnas. for each subgenomic rna, six to nine cdna clones were isolated by means of reve ... | 1993 | 8345361 |
| sequences of 3' end of genome and of 5' end of open reading frame 1a of lactate dehydrogenase-elevating virus and common junction motifs between 5' leader and bodies of seven subgenomic mrnas. | the sequences of the 3'-terminal 3.7 kb of the genome and of a 1.7 kb 5' end cdna clone of one isolate of lactate dehydrogenase-elevating virus (ldv) are reported. the 3' end sequence encodes six major independent open reading frames (orfs 2 to 7), which are overlapping by between one and 130 nucleotides. each orf is expressed at the 5' end of one of six 3'-coterminal subgenomic mrnas (mrnas 2 to 7, respectively; 3.5 to 0.8 kb). the smallest mrna, mrna 7, encodes the nucleocapsid protein, vp1; m ... | 1993 | 8385693 |
| complete genomic sequence and phylogenetic analysis of the lactate dehydrogenase-elevating virus (ldv). | the apparently complete sequence of the rna genome of the neurovirulent isolate of lactate dehydrogenase-elevating virus (ldv-c) has been determined. the ldv-c genome is at least 14,222 nucleotides in length and contains eight open reading frames (orfs). orf 1a, which encodes a protein of 242.8 kda and is located at the 5' end of the genome, contains at least two putative papain-like cysteine protease domains, and one putative chymotrypsin-like serine protease domain. this orf terminates with a ... | 1993 | 8389075 |
| lelystad virus, the causative agent of porcine epidemic abortion and respiratory syndrome (pears), is related to ldv and eav. | the genome of lelystad virus (lv), the causative agent of porcine epidemic abortion and respiratory syndrome (previously known as mystery swine disease), was shown to be a polyadenylated rna molecule. the nucleotide sequence of the lv genome was determined from a set of overlapping cdna clones. a consecutive sequence of 15,088 nucleotides was obtained. eight open reading frames (orfs) that might encode virus-specific proteins were identified. orf1a and orf1b are predicted to encode the viral rna ... | 1993 | 8517032 |
| antigenic comparison of canadian and us isolates of porcine reproductive and respiratory syndrome virus using monoclonal antibodies to the nucleocapsid protein. | fifteen canadian field isolates of porcine reproductive and respiratory syndrome (prrs) virus from quebec and ontario were compared with 5 us prrs virus (prrsv) isolates and with the european lelystad isolate using monoclonal antibodies (mabs) sdow17, ep147, and vo17 directed to the 15-kda nucleocapsid protein of prrsv. all canadian and us isolates tested by indirect immunofluorescence were recognized by the 3 mabs, and individual titers of mabs towards canadian and us prrsv isolates were simila ... | 1995 | 8521358 |
| nucleocapsid protein n of lelystad virus: expression by recombinant baculovirus, immunological properties, and suitability for detection of serum antibodies. | the orf7 gene, encoding the nucleocapsid protein n of lelystad virus (lv), was inserted downstream of the p10 promoter into autographa californica nuclear polyhedrosis virus (baculovirus). the resulting recombinant baculovirus, designated bac-orf7, expressed a 15-kda protein in insect cells. this protein was similar in size to the n protein expressed by lv in cl2621 cells when it was analyzed on sodium dodecyl sulfate-polyacrylamide gels. the n protein expressed by bac-orf7 was immunoprecipitate ... | 1995 | 8574824 |
| comparison of the pathogenicity of two us porcine reproductive and respiratory syndrome virus isolates with that of the lelystad virus. | the lelystad virus or one of two us isolates (vr2385, vr2431) of porcine reproductive and respiratory syndrome virus were given intranasally to 25 4-week-old cesarian-derived colostrum-deprived pigs. pigs from these groups were necropsied at 1, 2, 3, 5, 7, 10, 15, 21, or 28 days postinoculation. the lelystad virus and vr2431 induced mild transient pyrexia, dyspnea, and tachypnea. vr2385 induced labored and rapid abdominal respiration, pyrexia, lethargy, anorexia, and patchy dermal cyanosis. all ... | 1995 | 8592800 |
| proteins encoded by open reading frames 3 and 4 of the genome of lelystad virus (arteriviridae) are structural proteins of the virion. | four structural proteins of lelystad virus (arteriviridae) were recognized by monoclonal antibodies in a western immunoblotting experiment with purified virus. in addition to the 18-kda integral membrane protein m and the 15-kda nucleocapsid protein n, two new structural proteins with molecular masses of 45 to 50 kda and 31 to 35 kda, respectively, were detected. monoclonal antibodies that recognized proteins of 45 to 50 kda and 31 to 35 kda immunoprecipitated similar proteins expressed from ope ... | 1996 | 8676504 |
| comparison of the antigen distribution of two us porcine reproductive and respiratory syndrome virus isolates with that of the lelystad virus. | one hundred 4-week-old cesarean-derived colostrum-deprived pigs were inoculated with one of two different us porcine reproductive and respiratory syndrome virus (prrsv) isolates (vr2385, vr2431) or the european lelystad virus to detect and compare the location and amount of virus antigen. interstitial pneumonia, myocarditis, lymphadenopathy, and encephalitis were consistently seen in all three groups; however, disease and lesions were more severe in the vr2385 group. immunohistochemical evaluati ... | 1996 | 8801709 |
| characterization of structural proteins of lelystad virus. | the genome of lelystad virus (lv), a positive-strand rna virus, is 15 kb in length and contains 8 open reading frames that encode putative viral proteins. synthetic polypeptides of 15 to 17 amino acids were selected from the amino acid sequences of orfs 2 to 7 and anti-peptide sera were raised in rabbits. using these anti-peptide sera and porcine anti-lv serum, we identified three structural proteins and assigned their corresponding genes. virions were found to contain a nucleocapsid protein of ... | 1995 | 8830491 |
| structural gene analysis of a quebec reference strain or porcine reproductive and respiratory syndrome virus (prrsv). | the 3' end genomic region of a québec prrsv reference strain (iaf-exp91), propagated in porcine alveolar macrophages (pam), was sequenced and compared to the prototype european strain, the lelystad virus (lv). the sequence, which represents the 3'-terminal 2834 nucleotides, encompassed 5 orfs corresponding to orfs 3 to 7 of lv. extensive genomic variations resulting from an important rate of nucleotide additions, substitutions, and deletions were demonstrated between the two viruses. indeed, the ... | 1995 | 8830492 |
| detection of related positive-strand rna virus genomes by reverse transcription/polymerase chain reaction using degenerate primers for common replicase sequences. | a set of degenerate sense and antisense primers were designed on the basis of short segments with identical amino acids in the predicted orf 1b replicase proteins of lactate dehydrogenase-elevating virus (ldv), equine arteritis virus (eav) and porcine reproductive and respiratory syndrome virus, strain lelystad virus (prrsv-lv), which are members of a new group of positive-strand rna viruses. reverse transcription/polymerase chain reaction amplification using this set of degenerate primers yield ... | 1995 | 8837898 |
| serological property and replication in cell cultures of porcine reproductive and respiratory syndrome viruses isolated in japan. | the serological property and replication in swine alveolar macrophages (sam) and marc-145 cell cultures of 35 porcine reproductive and respiratory syndrome (prrs) viruses isolated in sam were investigated. all the isolates were reacted almost equally with antisera against three japanese isolates including edrd-1 strain (american type) in immunoperoxidase monolayer assay (ipma), but weakly or did not react with antiserum against lelystad virus (european type) indicating that the japanese isolates ... | 1996 | 8877986 |
| identification and characterization of a sixth structural protein of lelystad virus: the glycoprotein gp2 encoded by orf2 is incorporated in virus particles. | previously we have shown that lelystad virus (lv) contains five structural proteins, a nucleocapsid protein n, an integral membrane protein m, and three glycoproteins gp3, gp4, and gp5. in this study we identified a sixth structural protein of lelystad virus. the protein has an apparent molecular weight of 29 to 30 kda, was recognized by an orf2-specific antipeptide serum in western immunoblotting using sucrose gradient purified lv virions, and was shown to be n-glycosylated. it was therefore de ... | 1996 | 8918532 |
| differential reactivity of a monoclonal antibody directed to the membrane protein of porcine reproductive and respiratory syndrome virus. | a monoclonal antibody (2c12) against the 19 kda membrane (m) protein of a canadian isolate of porcine reproductive and respiratory syndrome (prrs) virus was produced. by indirect immunofluorescence (iif) cytoplasmic fluorescence was observed in infected cells, but the pattern of fluorescence was generally different and intensity was weaker than that observed using the nucleocapsid protein-directed monoclonal antibody sdow17. when tested by iif towards a total of 26 prrs virus isolates from canad ... | 1997 | 9008806 |
| porcine reproductive and respiratory syndrome: temperature and ph stability of lelystad virus and its survival in tissue specimens from viraemic pigs. | we investigated the growth of lelystad virus (lv) in porcine alveolar macrophages, the thermal and ph stability of the virus in cell culture medium, and its survival in tissue specimens from viraemic pigs. lelystad virus grew to titres of 10(6) tcid50/ml, which were found at 40 h after virus inoculation when the macrophage cultures showed a cytopathic effect of approximately 40%. in culture medium at ph 7.5, lv was stable for prolonged periods of storage at -70 degrees c and -20 degrees c. at hi ... | 1994 | 9133061 |
| genetic variation and phylogenetic relationships of 22 porcine reproductive and respiratory syndrome virus (prrsv) field strains based on sequence analysis of open reading frame 5. | porcine reproductive and respiratory syndrome virus (prrsv) strains from 13 states in the united states, guatemala and canada were used to compare the envelope glycoprotein gene (orf 5) nucleotide and deduced amino acid sequences. the gene was the same size, 603 nt, for all the 22 field strains. these strains had 89-94% amino acid identity compared to reference strain vr 2332. a putative signal sequence and cleavage site between residues 31 and 32 was identified and three potential glycosylation ... | 1997 | 9191863 |
| molecular characterization of lelystad virus. | lelystad virus (lv), the prototype of porcine reproductive respiratory syndrome virus, is a small enveloped virus, containing a positive strand rna genome of 15 kb. lv is tentatively classified in the family arteriviridae, which consists of lactate dehydrogenase-elevating virus (ldv), equine arteritis virus (eav) and simian hemorrhagic fever virus (shfv). these viruses have a similar genome organization and replication strategy as coronaviruses, but the size of the genome is much smaller (12-15 ... | 1997 | 9220614 |
| comparative morphogenesis of three prrs virus strains. | the morphogenesis of a dutch prrs field strain virus (lelystad virus) was studied and compared to that of a u.s. field strain vr2332 and its attenuated vaccine strain jj1882. porcine lung alveolar macrophages (plam) and cl2621 cells were infected with high doses of virus (moi = 10). at 4, 6, 9, 12, 18, 24, and 48 h post infection (hpi) cells were fixed for electronmicroscopy or for detection of viral antigens by immunoperoxidase staining. from 6 hpi on, viral antigens were detected in the cytopl ... | 1997 | 9220615 |
| posttranslational processing and identification of a neutralization domain of the gp4 protein encoded by orf4 of lelystad virus. | gp4 is a minor structural glycoprotein encoded by orf4 of lelystad virus (lv). when it was immunoprecipitated from cell lysates and extracellular virus of cl2621 cells infected with lv, it was shown to have an apparent molecular mass of approximately 28 and 31 kda, respectively. this difference in size occurred because its core n-glycans were modified to complex type n-glycans during the transport of the protein through the endoplasmic reticulum and golgi compartment. a panel of 15 neutralizing ... | 1997 | 9223499 |
| monoclonal antibodies to the orf5 product of porcine reproductive and respiratory syndrome virus define linear neutralizing determinants. | complementary dna encoding the orf5 gene of a quebec reference isolate (iaf-klop) of porcine reproductive and respiratory syndrome virus (prrsv) was cloned into the prokaryotic expression vectors pgex-4t and pet21a to produce orf5-glutathione s-transferase and orf5-polyhistidine fusion proteins. five hybridoma cell lines producing monoclonal antibodies (mabs) to the 25 kda viral envelope glycoprotein (gp5) were obtained from balb/c mice immunized with the affinity chromatography-purified gst-orf ... | 1997 | 9266981 |
| performance of elisa antigens prepared from 8 isolates of porcine reproductive and respiratory syndrome virus with homologous and heterologous antisera. | porcine reproductive and respiratory syndrome virus (prrsv) elisa antigens of high quality were produced using 8 different isolates of prrsv: the european lelystad virus (lv), the u.s. mn-1b, 89-46448, 93-44927, and 93-24025b, and the canadian lhva-93-3, pa-8 and gh-6 virus isolates. the performance of each of these 8 antigens and a commercial prrsv antibody test kit (idexx's herdchek) were measured against antisera raised in 5 groups of 6 piglets inoculated with either lv, mn-1b, 89-46448, 93-4 ... | 1997 | 9342455 |
| infectious transcripts from cloned genome-length cdna of porcine reproductive and respiratory syndrome virus. | the 5'-terminal end of the genomic rna of the lelystad virus isolate (lv) of porcine reproductive and respiratory syndrome virus was determined. to construct full-length cdna clones, the 5'-terminal sequence was ligated to cdna clones covering the complete genome of lv. when rna that was transcribed in vitro from these full-length cdna clones was transfected into bhk-21 cells, infectious lv was produced and secreted. the virus was rescued by passage to porcine alveolar lung macrophages or cl2621 ... | 1998 | 9420236 |
| differentiation between porcine reproductive and respiratory syndrome virus isolates by restriction fragment length polymorphism of their orfs 6 and 7 genes. | three distinct antigenic profiles were identified by comparing the reactivities of 15 canadian field isolates, the attenuated u.s. vaccine (ingelvac mlv) strain and 2 european reference strains (lelystad and weybridge) of the porcine reproductive and respiratory syndrome virus (prrsv) by indirect immunofluorescence with a set of 4 monoclonal antibodies to the nucleocapsid (n) protein and 2 other to the matrix (m) protein. in the present study, 9 canadian isolates for which the sequences were det ... | 1998 | 9553709 |
| quantitation of porcine reproductive and respiratory syndrome virus rna in semen by single-tube reverse transcription-nested polymerase chain reaction. | porcine reproductive and respiratory syndrome virus (prrsv) is in boar semen for extended periods of time as determined by reverse transcription-nested polymerase chain reaction (rt-npcr) assay. the concentration of prrsv rna in semen and the biological significance of the detection level, however, remain to be resolved. in order to determine the concentration of prrsv vr-2332 (a prototypic strain of north american isolates) in semen following infection, we established a 'standard curve'-quantit ... | 1998 | 9672134 |
| an infectious cdna clone of porcine reproductive and respiratory syndrome virus. | a plasmid containing a full-length cdna copy of the lelystad virus isolate (lv) of porcine reproductive and respiratory syndrome virus was constructed. when rna that was transcribed in vitro from this full-length cdna clone was transfected to bhk-21 cells, infectious lv was produced and secreted. the virus was rescued by passage to porcine alveolar lung macrophages or cl2621 cells. when infectious transcripts were transfected to porcine alveolar lung macrophages or cl2621 cells no infectious vir ... | 1998 | 9782281 |
| genetic variation in the prrs virus. | porcine reproductive and respiratory syndrome (prrs) is characterized by late-term abortions and stillbirths in sows and respiratory difficulties in nursery pigs. the disease appeared in europe and north america at approximately the same time between 1985 and 1990. the prrs virus was isolated shortly thereafter and demonstrated unexpectedly profound differences between european (lelystad) and north american (vr2332) isolates as measured by serological crossreactivity and nucleotide sequence simi ... | 1998 | 9782359 |
| porcine reproductive and respiratory syndrome virus comparison: divergent evolution on two continents. | porcine reproductive and respiratory syndrome virus (prrsv) is a recently described arterivirus responsible for disease in swine worldwide. comparative sequence analysis of 3'-terminal structural genes of the single-stranded rna viral genome revealed the presence of two genotypic classes of prrsv, represented by the prototype north american and european strains, vr-2332 and lelystad virus (lv), respectively. to better understand the evolution and pathogenicity of prrsv, we obtained the 12,066-ba ... | 1999 | 9847330 |
| localization and fine mapping of antigenic sites on the nucleocapsid protein n of porcine reproductive and respiratory syndrome virus with monoclonal antibodies. | the purpose of this study was to analyze the antigenic structure of the nucleocapsid protein n of the lelystad virus isolate of porcine reproductive and respiratory syndrome virus (prrsv) and to identify antigenic differences between this prototype european isolate and other north american isolates. to do this, we generated a panel of monoclonal antibodies (mabs) directed against the n protein of lelystad virus and tested them in competition assays with other n-specific mabs described previously ... | 1998 | 9875321 |
| antigenic and genetic variations of the 15 kd nucleocapsid protein of porcine reproductive and respiratory syndrome virus isolates. | the antigenic variability of the 15 kd nucleocapsid protein of porcine reproductive and respiratory syndrome (prrs) virus was characterized with a panel of 24 monoclonal antibodies (mabs) raised against the american prrs virus isolate isu-p. five continuous epitopes designated eporf7-a through e were revealed by the reactivity pattern of these mabs with 67 american field isolates, two modified-live vaccine viruses, and the european lelystad virus as determined by the indirect immnofluorescence a ... | 1999 | 10226618 |
| determination of the complete nucleotide sequence of a vaccine strain of porcine reproductive and respiratory syndrome virus and identification of the nsp2 gene with a unique insertion. | the complete nucleotide sequence of the genomic rna of a vaccine strain (sp) of porcine reproductive and respiratory syndrome virus (prrsv) was determined. it shares approximately 94% identity of nucleotide sequence with two recently reported north american strains, 16244b and vr2332, but only 78% with a european strain, lelystad virus (lv). its genome is the longest among the four published complete sequences of prrsv, due to an insertion in the nsp2-encoding region. compared to nsp2 of the nor ... | 2000 | 10881675 |
| [the discovery of the lelystad virus. a high point in dutch veterinary research during the last ten years (1990-1999)]. | | 2000 | 10950729 |
| highly cited article published in the veterinary quarterly in 1991. | in early 1991, the dutch pig industry was struck by the so-called mystery swine disease. large-scale laboratory investigations were undertaken to search for the aetiological agent. we focused on isolating viruses and mycoplasmas, and we tested paired sera of affected sows for antibodies against ten known pig viruses. the mycoplasmas m. hysonoviae, m. hyopneumoniae, and acheloplasma laidlawii, and the viruses encephalomyocarditis virus and porcine enterovirus types 2 and 7 were isolated from indi ... | 2000 | 10952439 |
| effects of a porcine reproductive and respiratory syndrome virus infection on the development of the immune response against pseudorabies virus. | the aim of this study was to investigate the effects of a porcine reproductive and respiratory syndrome virus (prrsv) infection on the development of the immune response after pseudorabies virus (prv) vaccination in pigs. pigs were intranasally inoculated with the european prrsv strain, lelystad virus ter huurne, and were vaccinated intramuscularly with prv 2 weeks later (lv-prv group). control pigs were vaccinated with prv only (prv group). eight weeks after prv vaccination, pigs from both grou ... | 2000 | 10973691 |
| categorization of north american porcine reproductive and respiratory syndrome viruses: epitopic profiles of the n, m, gp5 and gp3 proteins and susceptibility to neutralization. | eleven epitopes were identified by murine monoclonal antibodies (mabs) that represented the n, m, gp5 and gp3 proteins of the north american (na) porcine reproductive and respiratory syndrome (prrs) virus, ky 35 (nvsl 46907). three discontinuous epitopes of the n and m proteins were designated eporf7-fd through hd and eporf6-ad through cd. five continuous epitopes of the gp5 and gp3 proteins were designated eporf5-a through c and eporf3-a and b. the mabs representing eporf5-c and eporf6-a and b ... | 2000 | 11003472 |
| expression of a foreign epitope by porcine reproductive and respiratory syndrome virus. | the potential of porcine reproductive and respiratory syndrome virus (prrsv) as a viral vector was explored by the insertion of a sequence encoding a foreign antigen into the infectious cdna clone of the lelystad virus isolate. an epitope of the hemagglutinin (ha) protein of human influenza a virus was introduced at the 5' end and at the 3' end of orf7, in each case resulting in a fusion protein between the ha epitope and the nucleocapsid (n) protein. furthermore, in the construct carrying the h ... | 2000 | 11118361 |
| viable porcine arteriviruses with deletions proximal to the 3' end of the genome. | in order to obtain attenuated live vaccine candidates of porcine reproductive and respiratory syndrome virus (prrsv), a series of deletions was introduced at the 3' end of the viral genome using an infectious cdna clone of the lelystad virus isolate. rna transcripts from the full-length cdna clones were transfected into bhk-21 cells. the culture supernatant of these cells was subsequently used to infect porcine alveolar macrophages to detect the production of progeny virus. it is shown that c-te ... | 2001 | 11602771 |
| porcine reproductive and respiratory syndrome (prrs) with special reference to clinical aspects and diagnosis. a review. | after a short introduction on porcine reproductive and respiratory syndrome (prrs) regarding the history, the first occurrence in several countries, and the causal virus, designated lelystad virus, a description is given of the clinical aspects and several diagnostic methods. after some general remarks on the clinical aspects, the epidemic and the endemic phase of the disease are described. regarding the diagnosis, special attention is paid to the detection of antibodies and of the prrs virus (p ... | 2002 | 12095084 |
| identification of radically different variants of porcine reproductive and respiratory syndrome virus in eastern europe: towards a common ancestor for european and american viruses. | we determined 22 partial porcine reproductive and respiratory syndrome virus (prrsv) orf5 sequences, representing pathogenic field strains mainly from poland and lithuania, and two currently available european-type live prrsv vaccines. also, the complete orf7 of two lithuanian and two polish strains was sequenced. we found that polish, and in particular lithuanian, prrsv sequences were exceptionally different from the european prototype, the lelystad virus, and in addition showed a very high nat ... | 2002 | 12124450 |
| chimeric arteriviruses generated by swapping of the m protein ectodomain rule out a role of this domain in viral targeting. | arteriviruses are enveloped, positive-strand rna viruses for which the two major envelope proteins gp(5) and m occur as disulfide-linked heterodimers. these were assumed to serve the viral targeting functions, but recent ectodomain swapping studies with equine arteritis virus (eav) indicate that the gp(5) protein does not determine arteriviral tropism. here, we focused on the short, 13- to 18-residue ectodomain of the m protein. using an infectious cdna clone of the lelystad virus isolate of por ... | 2002 | 12490397 |
| the primary neutralization epitope of porcine respiratory and reproductive syndrome virus strain vr-2332 is located in the middle of the gp5 ectodomain. | pigs infected with porcine respiratory and reproductive syndrome virus (prrsv) strain vr-2332 were found to generate high levels of antibodies (abs) that bound in an indirect elisa to synthetic peptides representing segments of the primary envelope glycoprotein (gp5) ectodomain of this virus. use of overlapping gp5 ectodomain peptides of various length indicated that the epitope recognized by the abs was located in the middle of the ectodomain (amino acids 36-52), in the same relative segment th ... | 2002 | 12491101 |
| genetic diversity and phylogenetic analysis of glycoprotein 5 of european-type porcine reproductive and respiratory virus strains in spain. | the gene encoding glycoprotein 5 (orf5) of 21 porcine reproductive and respiratory syndrome virus (prrsv) isolates from spain and two european-type vaccines currently available in that country were analysed using rt-pcr and sequencing. sequences were then compared with other european-type sequences available through genbank. results showed percentages of similarity to lelystad virus (lv), which, in most cases, were below 90 %. in contrast, two strains were very similar (>99 %) to a prrsv variant ... | 2003 | 12604802 |
| safety and protective efficacy of porcine reproductive and respiratory syndrome recombinant virus vaccines in young pigs. | three porcine reproductive and respiratory syndrome virus (prrsv) recombinants, generated by mutagenesis of an infectious cdna clone of the lelystad virus (lv) isolate, were tested for their safety and protective efficacy as potential prrsv vaccines in pigs. recombinant vabv688 contains two amino acid substitutions in the minor structural protein gp(2) resulting in improved growth on cell line cl2621; in recombinant vabv707 the region encoding the ectodomain of the major unglycosylated membrane ... | 2003 | 12744891 |
| apoptosis in the lungs of pigs infected with porcine reproductive and respiratory syndrome virus and associations with the production of apoptogenic cytokines. | apoptosis was studied in the lungs of pigs during an infection with a european strain of porcine reproductive and respiratory syndrome virus (prrsv) and it was examined if cytokines were involved in the induction of apoptosis. twenty-two 4- to 5-week-old gnotobiotic pigs were inoculated intranasally with 10(6.0) tcid50 of the lelystad virus and euthanised between 1 and 52 days post inoculation (pi). the lungs and broncho-alveolar lavage (bal) cells were assessed both for virus replication and ap ... | 2003 | 12791235 |
| heterogeneity in nsp2 of european-like porcine reproductive and respiratory syndrome viruses isolated in the united states. | recently, isolates of porcine reproductive and respiratory syndrome virus (prrsv) that possess nucleotide sequences similar to european isolates have been reported in united states herds. the origin, diversity and prevalence of european-like north american prrsv isolates in the u.s. remain unknown. nucleotide sequence analysis of the 12kb orf1 of a north american isolate, sdprrs 01-08 (01-08), showed 93.7% identity with lelystad virus (lv), the prototypic european isolate, but only 58% identity ... | 2004 | 15019241 |
| gp5 ectodomain epitope of porcine reproductive and respiratory syndrome virus, strain lelystad virus. | sera from pigs infected with the european porcine reproductive and respiratory syndrome virus (prrsv), strain lelystad virus (lv), were screened by indirect elisa for antibodies that bound to a series of overlapping synthetic peptides covering amino acids (aa) 19-60 of the primary envelope glycoprotein (gp)5. antibodies were detected that bound to an epitope(s) located in an ectodomain segment composed of aa 38-54. the antibodies strongly cross-reacted with peptides specific for the north americ ... | 2004 | 15084406 |
| genetics and geographical variation of porcine reproductive and respiratory syndrome virus (prrsv) in thailand. | the thai isolates of porcine reproductive and respiratory syndrome virus (prrsv) were obtained from the chulalongkorn university-veterinary diagnostic laboratory (cu-vdl). virus isolation was confirmed by immunoperoxidase monolayer assay (ipma) using sdow-17. the virus genotype was determined using nested multiplex rt-pcr (nm rt-pcr) of orf 1b. the nm rt-pcr was able to detect at least 10tcid50/ml of prrsv. of 137 thai isolates, 66.42% belonged to the european (eu) genotype and 33.58% to the nor ... | 2004 | 15201029 |
| genomic characterization of two chinese isolates of porcine respiratory and reproductive syndrome virus. | the genomes of two isolates of porcine respiratory and reproductive syndrome virus (prrsv) from china, designated hb-1(sh)/2002 and hb-2(sh)/2002, were sequenced and analyzed. the size of the genomes of hb-1(sh)/2002 and hb-2(sh)/2002 were 15,411 and 15,373 nucleotides respectively, excluding the poly(a) tails. comparative analysis with the genomic sequences of another chinese isolate (bj-4) and north american (vr2332) and european (lelystad virus, lv) viruses revealed that hb-1(sh)/2002 shared ... | 2004 | 15221535 |
| detection of u.s., lelystad, and european-like porcine reproductive and respiratory syndrome viruses and relative quantitation in boar semen and serum samples by real-time pcr. | transmission of porcine reproductive and respiratory syndrome virus (prrsv) via boar semen has been documented. since semen is widely disseminated for artificial insemination and the virus can cause significant health and economic consequences, it is essential to have well-validated, rapid diagnostic techniques to detect and quantitate the virus for diagnostic and research purposes. previously, boar semen was tested by a nested pcr (npcr) assay which was compared to the "gold standard" swine bio ... | 2004 | 15472293 |
| effect of virus-specific antibodies on attachment, internalization and infection of porcine reproductive and respiratory syndrome virus in primary macrophages. | porcine reproductive and respiratory syndrome virus (prrsv) induces respiratory distress in young pigs and reproductive failure in sows. in prrsv infected pigs, virus persists for several weeks to several months. although ipma antibodies are detected from 7 days post inoculation (pi), virus neutralizing (vn) antibodies are commonly detected starting from 3 weeks pi with an sn test on marc-145 cells. since infection of marc-145 cells is quite different compared to infection of macrophages, the in ... | 2004 | 15507304 |
| the primary gp5 neutralization epitope of north american isolates of porcine reproductive and respiratory syndrome virus. | i have used indirect elisa with overlapping synthetic peptides representing the gp5 ectodomain to study the generation and specificity of peptide-binding abs in pigs that were infected in utero with porcine reproductive and respiratory syndrome virus (prrsv) strain vr2332 and in north american field sera submitted for prrsv infection diagnosis. peptide-binding abs appeared in sera of the vr2332-infected pigs within about 30 days post-farrowing (dpf), reaching maximum titers 100-200 dpf and then ... | 2004 | 15507310 |
| epitope specificity of monoclonal antibodies to the n-protein of porcine reproductive and respiratory syndrome virus determined by elisa with synthetic peptides. | in an attempt to develop an alternate to elisas using recombinant n-proteins as antigen for the sero-diagnosis of porcine reproductive and respiratory syndrome virus (prrsv) infections of pigs i have measured the binding of nine anti-n-protein mabs, which had been previously generated by various investigators, to overlapping peptides encompassing amino acids 19-70 of the n-proteins of the north american prototype (vr2332) and the european prototype (lelystad virus, lv) of prrsv. i also measured ... | 2005 | 15661331 |
| evolution of orf5 of spanish porcine reproductive and respiratory syndrome virus strains from 1991 to 2005. | orf5 sequences of porcine reproductive and respiratory syndrome virus (prrsv) were analysed to determine genetic diversity, codon usage, positive and negative selection sites and potential changes in the predicted glycoprotein 5 (gp5). a hypothetical gp5 containing all selected sites was constructed to determine its characteristics. these sequences corresponded to isolates obtained 10 years apart (1991-1995, 18 strains) and a second set (n = 46) from 2000 to 2005. similarity to lelystad virus (l ... | 2006 | 16269197 |
| assessment of the efficacy of commercial porcine reproductive and respiratory syndrome virus (prrsv) vaccines based on measurement of serologic response, frequency of gamma-ifn-producing cells and virological parameters of protection upon challenge. | the efficacy of two different types of commercial vaccines against prrsv (euro-type) was evaluated based on clinical parameters upon challenge as well as post-challenge virological profiles (viremia and viral load in tissues upon necropsy, measured in both cases by quantitative real time pcr). in an attempt to establish correlates of protective immunity, two commonly proposed parameters predictive of immunity were measured: (1) serologic responses (elisa and neutralizing antibodies), (2) frequen ... | 2007 | 17376612 |
| swine reproductive and respiratory syndrome in québec: isolation of an enveloped virus serologically-related to lelystad virus. | sera were collected from convalescent sows and sick piglets from six pig farms in southern quebec that have experienced outbreaks of the so-called porcine reproductive and respiratory syndrome. by indirect immunoperoxidase, a few of these sera (4 of 14) (28.6%) were found to be positive for antibody to the lelystad virus, whereas by indirect immunofluorescence 30 of 36 (83.3%) were positive for antibody to the antigenically-related american isolate atcc-vr2332. pregnant sows inoculated intranasa ... | 1992 | 17424133 |
| porcine reproductive and respiratory syndrome virus (prrsv) infection in wild boars. | the porcine reproductive and respiratory syndrome (prrs) is one of the economically most important swine diseases worldwide. the virus can be spread by viraemic and persistent infected pigs. spread and infection are advanced in areas with high herd and population densities. as wild boars have been found seropositive for prrsv in germany, france, and the usa, exchange between wild and domestic pig populations may exist. however, comprehensive information on prrsv infection in wild boars is presen ... | 2009 | 19131188 |
| development of a one-step real-time quantitative pcr assay based on primer-probe energy transfer for the detection of porcine reproductive and respiratory syndrome virus. | a one-step real-time rt-pcr method has been developed for the simultaneous detection of both genotypes of porcine reproductive and respiratory syndrome virus (prrsv). the assay is based on primer-probe energy transfer, and the most important advantage of this is the relative tolerance towards mutations in the target-probe region. the primers and the probe were designed using an alignment of 235 type 1 (including all subtypes) and type 2 prrsv strains. according to the alignment, multiple degener ... | 2009 | 19200443 |
| functional impairment of prrsv-specific peripheral cd3+cd8high cells. | the replication of porcine reproductive and respiratory syndrome virus (prrsv) in lungs and lymphoid tissues of prrsv-infected pigs is already strongly reduced before the appearance of neutralizing antibodies, indicating that other immune mechanisms are involved in eliminating prrsv at those sites. this study aimed to determine whether prrsv lelystad virus (lv)-specific cytotoxic t-lymphocytes (ctl) can efficiently eliminate prrsv-infected alveolar macrophages. therefore, ctl assays were perform ... | 2009 | 19445889 |
| genetic analysis of orf5 of recent korean porcine reproductive and respiratory syndrome viruses (prrsvs) in viremic sera collected from mlv-vaccinating or non-vaccinating farms. | the 23 open reading frame (orf) 5 sequences of korean type ii porcine reproductive and respiratory syndrome virus (prrsv) were collected from viremic sera from the (modified live vaccine) mlv-vaccinating and non-vaccinating farms from 2007 to 2008. the samples were phylogenetically analyzed with previous orf5 sequences, including type i korean prrsv, and previously reported or collected sequences from 1997 to 2008. a mn184-like subgroup of type ii korean prrsv was newly identified in the viremic ... | 2009 | 19461207 |
| comparative analysis of complete nucleotide sequence of porcine reproductive and respiratory syndrome virus (prrsv) isolates in thailand (us and eu genotypes). | porcine reproductive and respiratory syndrome virus (prrsv) is a causative agent of porcine reproductive and respiratory syndrome (prrs). in this study, the complete nucleotide sequences of the selected two thai prrsv isolates, eu (01cb1) and us (01np1) genotypes were determined since both isolates are the thai prototypes. | 2009 | 19754975 |
| prevalence and phylogenetic analysis of the isolated type i porcine reproductive and respiratory syndrome virus from 2007 to 2008 in korea. | the first korean strain of porcine reproductive and respiratory syndrome virus (prrsv) was isolated in 1997, and it exhibited high similarity to strain vr-2332 (type ii prrsv; north american type). recently, however, infection with type i prrsv (european type) has also been reported in korea. to date, preliminary data about type i prrsv prevalence in korea have not been reported. here, using reverse transcriptase (rt)-pcr, we analyzed 383 archived field samples from 101 pig farms in korea that w ... | 2010 | 20063118 |
| complete genomic characterization of a chinese isolate of porcine reproductive and respiratory syndrome virus. | the genome of one isolate of porcine reproductive and respiratory syndrome virus (prrsv) from china, designated gdqy2, was sequenced and analyzed. the full length of gdqy2 was 15,215 nucleotides, excluding the poly(a) tail. comparative analysis with the genomic sequences of numerous worldwide north american isolates revealed that gdqy2 shared 85.0-98.9% identity with these isolates, but only 60.9% with the european virus-lv (lelystad virus), indicating that this new chinese isolate was closely r ... | 2011 | 20667670 |
| a variable region in gp4 of european-type porcine reproductive and respiratory syndrome virus induces neutralizing antibodies against homologous but not heterologous virus strains. | porcine reproductive and respiratory syndrome virus (prrsv) can induce severe reproductive failure in sows, and is involved in the porcine respiratory disease complex. the glycoprotein gp4 of the european prototype prrsv strain lelystad virus (lv) contains a linear neutralizing epitope that is located in a highly variable region. the current study aimed to evaluate the antibody response against this and other epitopes on gp4 to infection of pigs with european-type prrsv. it was shown that three ... | 2010 | 20712485 |
| gp4-specific neutralizing antibodies might be a driving force in prrsv evolution. | the structural envelope glycoprotein gp4 of european porcine reproductive and respiratory syndrome virus (prrsv) strains contains a highly variable neutralizing epitope that is susceptible to neutralizing antibody-mediated selective pressure in vitro. in this study, it was analyzed what happens with this neutralizing epitope during infection in vivo in the presence of neutralizing antibodies. a neutralizing antibody-mediated selective pressure was created in 30 pigs by vaccination prior to inocu ... | 2010 | 20837070 |
| characterization of a circulating prrsv strain by means of random pcr cloning and full genome sequencing. | abstract: prrs is a pig disease of major economic importance that causes respiratory and reproductive problems in pigs. over the last years it has become clear that prrsv heterogeneity is increasing. consequently, this has a potential impact on diagnosis and strategies to counter this disease. the use of sequence-independent pcr techniques for the detection and characterization of prrsv could be useful to bypass problems associated with the heterogeneity of this virus.a random pcr cloning approa ... | 2011 | 21477345 |
| characterization of antigenic regions in the porcine reproductive and respiratory syndrome virus by the use of peptide-specific serum antibodies. | the porcine reproductive and respiratory syndrome virus (prrsv) is an rna virus that causes reproductive failure in sows and boars, and respiratory disease in pigs of all ages. antibodies against several viral envelope proteins are produced upon infection, and the glycoproteins gp4 and gp5 are known targets for virus neutralization. still, substantial evidence points to the presence of more, yet unidentified neutralizing antibody targets in the prrsv envelope proteins. the current study aimed to ... | 2011 | 21554913 |
| increased pathogenicity of european porcine reproductive and respiratory syndrome virus is associated with enhanced adaptive responses and viral clearance. | porcine reproductive and respiratory syndrome (prrs) is one of the most economically important diseases of swine worldwide. since its first emergence in 1987 the prrs virus (prrsv) has become particularly divergent with highly pathogenic strains appearing in both europe and asia. however, the underlying mechanisms of prrsv pathogenesis are still unclear. this study sets out to determine the differences in pathogenesis between subtype 1 and 3 strains of european prrsv (prrsv-i), and compare the i ... | 2012 | 23313323 |
| emergence of a novel highly pathogenic porcine reproductive and respiratory syndrome virus in china. | from 2014 to 2015, four novel highly pathogenic prrs virus (hp-prrsv) strains named 14ly01-fj, 14ly02-fj 15ly01-fj, and 15ly02-fj were isolated from high morbidity (100%) and mortality (40%-80%) in piglets and sows in fujian province. to further our knowledge about these novel virus strains, we characterized their complete genomes and determined their pathogenicity in piglets. full-length genome sequencing analysis showed that these four isolates were closely related to type 2 (north american ty ... | 2017 | 28198110 |
| complete genomic characterization of two european-genotype porcine reproductive and respiratory syndrome virus isolates in fujian province of china. | porcine reproductive and respiratory syndrome (prrs) is considered one of the most devastating swine diseases worldwide, resulting in immense economic losses. prrs virus (prrsv) is divided into two major genotypes, european (type 1) and the north american (type 2). type 1 prrsv have recently emerged in fujian province (south china), and this might have a significant impact on the chinese pig industry. from 2013 to 2014, two type 1 prrsv strains, named fjeu13 and fjqeu14, were isolated from pigle ... | 2017 | 27858288 |
| comparative analysis of cytokine transcript profiles within mediastinal lymph node compartments of pigs after infection with porcine reproductive and respiratory syndrome genotype 1 strains differing in pathogenicity. | porcine reproductive and respiratory syndrome virus (prrsv) induces a weak immune response enabling it to persist in different organs of infected pigs. this has been attributed to the ability of prrsv to influence the induction of cytokine responses. in this study, we investigated the cytokine transcriptional profiles in different compartments of the mediastinal lymph node of pigs infected with three genotype 1 prrsv strains of differing pathogenicity: the low virulence prototype lelystad virus ... | 2015 | 25889072 |
| diagnosis of the lelystad strain of porcine reproductive and respiratory syndrome virus infection in individually housed pigs: comparison between serum and oral fluid samples for viral nucleic acid and antibody detection. | there has been a developing interest in the use of oral fluid for the diagnosis of different pathogens such as porcine reproductive and respiratory syndrome virus (prrsv). prrsv and prrsv-specific antibodies have been shown to be present in oral fluid samples, but the correlation between diagnostic results in oral fluid and serum samples has been insufficiently addressed. studies investigating this correlation focused on boars older than 6 months and type 2 strains, but it is known that the outc ... | 2015 | 25525137 |
| pathology and virus distribution in the lung and lymphoid tissues of pigs experimentally inoculated with three distinct type 1 prrs virus isolates of varying pathogenicity. | porcine reproductive and respiratory syndrome (prrs) continues to be the most economically important disease of swine worldwide. the appearance of highly pathogenic prrs virus (prrsv) strains in europe and asia has raised concerns about this disease and initiated increased efforts to understand the pathogenesis. in this study, we have compared the pathology and the virus distribution in tissues of pigs experimentally inoculated with three different genotype 1 prrsv isolates. sixty 5-week-old pig ... | 2016 | 25382098 |
| complete genome sequence of european genotype porcine reproductive and respiratory syndrome virus strain lneu12 in northern china. | we report the complete genome sequence of a european genotype porcine reproductive and respiratory syndrome virus isolated from swine in northern china in 2012. genome alignment revealed that the virus (lneu12) strain shares 90.1% nucleotide identity with the european prototype lelystad virus. here, we announce the complete genome sequence of lneu12. | 2014 | 25301644 |
| efficacy of type 2 prrsv vaccine against chinese and vietnamese hp-prrsv challenge in pigs. | porcine reproductive and respiratory syndrome virus (prrsv) causes significant reproductive losses in the sow herd and respiratory disease in growing pigs. the virus belongs to the family arteriviridae and there are two major genotypes. type 1 is represented by lelystad virus, the european prototype virus, and type 2 is represented by the north american prototype virus, vr-2332. depending on husbandry, immune status of the herd, and virulence of the isolate, the severity of disease and magnitude ... | 2014 | 25285886 |
| complete genomic characterization of a porcine reproductive and respiratory syndrome virus isolate in xinjiang province of china. | porcine reproductive and respiratory syndrome (prrs) is a swine disease of major economic importance that causes reproductive and respiratory problems in pigs. in the present study, one strain of porcine reproductive and respiratory syndrome virus (prrsv) was isolated in xinjiang province, northwest china, designated xju-1. the full-length genome of xju-1 was found to be 14,987 nucleotides in length, including the poly(a) tail. comparative analysis with the genomic sequences of type 2 isolates r ... | 2015 | 25272960 |