Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| pathogenesis of porcine reproductive and respiratory syndrome virus-induced increase in susceptibility to streptococcus suis infection. | eighty 3-week-old crossbred pigs were randomly assigned to six groups (13-14 pigs/group). group 1 pigs served as uninoculated controls, group 2 pigs were inoculated intranasally (i.n.) with streptococcus suis serotype 2, group 3 pigs were inoculated i.n. with a modified live porcine reproductive and respiratory syndrome virus (prrsv) vaccine, group 4 pigs were inoculated i.n. with the same vaccine and with s. suis, group 5 pigs were inoculated i.n. with vr-2385 (a high-virulence strain of prrsv) ... | 2000 | 10714643 |
| associations between genetics, farm characteristics and clinical disease in field outbreaks of porcine reproductive and respiratory syndrome virus. | porcine reproductive and respiratory syndrome (prrs) is a disease of domestic swine characterized by exceptionally high clinical variability. this study addresses the question of whether clinical variability in prrs results from (a) genetic variation among viral isolates and/or (b) variation in management practices among farms on which isolates are found. genetic data (open reading frame 5 gene sequences) and data on farm characteristics and associated clinical disease signs were collected for 6 ... | 2000 | 10718497 |
| introduction, persistence and fade-out of porcine reproductive and respiratory syndrome virus in a dutch breeding herd: a mathematical analysis. | the objective of this study was to investigate the dynamics of prrsv infection and to quantify transmission within a breeding herd, and its impact on herd performance. for this purpose a longitudinal study was performed in a closed breeding herd of 115 sows. statistical methods and monte carlo simulations based on stochastic sir models were used to analyse the observational data. moreover, a case-control study was performed to determine whether seroconversion of sows during gestation was associa ... | 2000 | 10722145 |
| prrsv, the virus. | porcine reproductive and respiratory syndrome virus (prrsv) is a positive-strand rna virus that belongs to the arteriviridae family. prrsv grows in primary alveolar macrophages and in monkey kidney cell lines. the genomic rna is approximately 15 kb. the genome encodes the rna replicase (orf1a and orf1b), the glycoproteins gp2 to gp5, the integral membrane protein m, and the nucleocapsid protein n (orfs 2 to 7). a comparison of nucleotide sequences of different strains indicates that european and ... | 2000 | 10726635 |
| a review of evidence for immunosuppression due to porcine reproductive and respiratory syndrome virus. | accounts of field disease and experimental studies involving porcine reproductive and respiratory syndrome (prrs) are reviewed for evidence of immunomodulation or immunosuppression by the causative virus. the conclusion is that immunomodulation through infection of alveolar macrophages is likely to occur, but that it is transient and at a local level, in the lung. there is some evidence for more subtle effects via more disseminated replication or induction of apoptosis with some isolates, but mo ... | 2000 | 10726636 |
| ultrastructural pathogenesis of the prrs virus. | porcine reproductive and respiratory syndrome virus (prrsv) was first isolated in swine alveolar macrophages (sams) and has subsequently been reported to replicate in other cell lines. entry of the virus inside the cell takes place by receptor-mediated endocytosis. following the entry of the virus into the cell, several not completely understood changes take place. prrsv has been reported to be an apoptotic-inductor virus both in vivo and in vitro. interestingly, it has been suggested that prrsv ... | 2000 | 10726637 |
| a brief review of procedures and potential problems associated with the diagnosis of porcine reproductive and respiratory syndrome. | experience has shown that, for a number of reasons, a diagnosis of porcine reproductive and respiratory syndrome (prrs) is sometimes difficult. in this review we discuss: (1) field observations and laboratory tests that are useful in arriving at a definitive diagnosis; (2) the impact of so-called atypical prrs on diagnostic procedures in north america; (3) the means by which diagnostic problems can often be circumvented by appropriate sample selection; and (4) methods used for presumptive identi ... | 2000 | 10726638 |
| the "colorful" epidemiology of prrs. | the paper describes the specifics of the epidemiology of the porcine reproductive and respiratory syndrome (prrs), that is its "behavior" as a communicable disease in porcine populations, and compares them to the general epidemiological characteristics of communicable diseases. this analysis shows that infection with the prrs virus "behaves" epidemiologically both as an epidemic and as an endemic disease: on the one hand it can spread like an epidemic in naïve populations, and on the other it se ... | 2000 | 10726639 |
| isolation and genome characterization of porcine reproductive and respiratory syndrome virus in p.r. china. | 2000 | 10730947 | |
| epidemiological and diagnostic observations following the elimination of porcine reproductive and respiratory syndrome virus from a breeding herd of pigs by the test and removal protocol. | the protocol of test and removal for the elimination of porcine reproductive and respiratory syndrome (prrs) virus was applied to an 825-sow breeding herd. all the adult animals were tested and serum samples analysed by elisa and polymerase chain reaction (pcr). eighty-eight animals (10 x 7 per cent) were removed from the herd and, of these, three were elisa-positive and pcr-positive, and 85 were elisa-positive and pcr-negative. they tended to be either individual sows, or groups of four to six ... | 2000 | 10731069 |
| a viral induced ubiquitin-specific protease (ubp) localized on porcine chromosome 5. | 2000 | 10754113 | |
| effect of cellular changes and onset of humoral immunity on the replication of porcine reproductive and respiratory syndrome virus in the lungs of pigs. | twenty-two 4- to 5-week-old gnotobiotic pigs were intranasally inoculated with 10(6.0) tcid(50) of porcine reproductive and respiratory syndrome virus (prrsv) (lelystad) and euthanized at different time intervals post-inoculation (p.i.). bronchoalveolar lavage (bal) cell populations were characterized, together with the pattern of virus replication and appearance of antibodies in the lungs. total bal cell numbers increased from 140x10(6) at 5 days p.i. to 948x10(6) at 25 days p.i. and remained a ... | 2000 | 10769076 |
| proinflammatory cytokines and viral respiratory disease in pigs. | swine influenza virus (siv), porcine respiratory coronavirus (prcv) and porcine reproductive and respiratory syndrome virus (prrsv) are enzootic viruses causing pulmonary infections in pigs. the first part of this review concentrates on known clinical and pathogenetic features of these infections. siv is a primary respiratory pathogen; prcv and prrsv, on the contrary, tend to cause subclinical infections if uncomplicated but they appear to be important contributors to multifactorial respiratory ... | 2000 | 10779199 |
| porcine reproductive and respiratory syndrome virus (prrsv): kinetics of infection in lymphatic organs and lung. | pigs were infected by the oronasal route with european isolates of the porcine reproductive and respiratory syndrome virus (prrsv; i10 and cobbelsdorf). the kinetics of infection in lymphatic organs and the lung were analysed by immunofluorescence detection of virus antigen, re-isolation of the virus and reverse transcription--polymerase chain reaction (rt-pcr) for prrsv-specific rna. the kinetics of prrsv infection proceeded in three phases, irrespective of the varying infestation of lymphatic ... | 2000 | 10780169 |
| an rna helicase, rhiv -1, induced by porcine reproductive and respiratory syndrome virus (prrsv) is mapped on porcine chromosome 10q13. | the impact of porcine reproductive and respiratory syndrome virus (prrsv) infection on porcine alveolar macrophages (mo) was examined by differential display reverse transcription pcr (ddrt-pcr). a prrsv-induced expressed gene tag (est) was used to isolate and identify a single cdna clone from a library prepared from porcine peripheral blood. rapid amplification of cdna ends (race) was employed to clone a 1.5 kb fragment at the 5' end of the mrna. dna sequencing identified an open reading frame ... | 2000 | 10799277 |
| a longitudinal study of serological patterns of respiratory infections in nine infected danish swine herds. | sixteen litters of seven pigs from each of nine danish farrow-to-finish herds were followed to investigate the serological patterns caused by natural infection with mycoplasma hyopneumoniae, pasteurella multocida toxin and actinobacillus pleuropneumoniae serotypes 2, 5-7, 12. in seven of the herds, pigs were followed as two separate cohorts started 4 weeks apart, and in two herds only one cohort was followed.a total of 999 pigs were included in the study. the pigs were blood sampled at weaning a ... | 2000 | 10821962 |
| heterogeneity of porcine reproductive and respiratory syndrome virus: implications for current vaccine efficacy and future vaccine development. | porcine reproductive and respiratory syndrome virus (prrsv) continues to be a major problem to the pork industry worldwide. increasing data indicate that prrsv strains differ in virulence in infected pigs and are biologically, antigenically, and genetically heterogeneous. it is evident that the current vaccines, based on a single prrsv strain, are not effective in protecting against infections with the genetically diverse field strains of prrsv. the recent outbreaks of atypical or acute prrs in ... | 2000 | 10831854 |
| monoclonal antibodies directed against conserved epitopes on the nucleocapsid protein and the major envelope glycoprotein of equine arteritis virus. | we recently developed a highly effective immunization procedure for the generation of monoclonal antibodies (mabs) directed against the porcine reproductive and respiratory syndrome virus (e. weiland, m. wieczorek-krohmer, d. kohl, k. k. conzelmann, and f. weiland, vet. microbiol. 66:171-186, 1999). the same method was used to produce a panel of 16 mabs specific for the equine arteritis virus (eav). ten mabs were directed against the eav nucleocapsid (n) protein, and five mabs recognized the maj ... | 2000 | 10834955 |
| the effect of porcine parvovirus and porcine reproductive and respiratory syndrome virus on porcine reproductive performance. | from a worldwide perspective, porcine parvovirus (ppv) and porcine reproductive and respiratory syndrome virus (prrsv) are the most common viral causes of porcine reproductive failure. a typical epidemic of ppv-induced reproductive failure is presented as an increased number of mummified fetuses and sometimes, entire litters are mummified. if infection with ppv is very early in gestation, the number of liveborn pigs may be further reduced as a result of embryonic death and resorption. during the ... | 2000 | 10844195 |
| competitive elisa for detection of antibodies to porcine reproductive and respiratory syndrome virus using recombinant e. coli-expressed nucleocapsid protein as antigen. | the 15 kda nucleocapsid (n) protein is the most abundant protein of the porcine reproductive and respiratory syndrome virus (prrsv), and is highly antigenic, which therefore makes it a suitable candidate for the detection of virus-specific antibodies and diagnosis of the disease. in this study, complementary dna corresponding to the entire n gene of the iaf-klop strain of prrsv was cloned into the pgex-4t-1 vector, and the n protein was expressed in escherichia coli fused to the glutathione s-tr ... | 2000 | 10856758 |
| lelystad-like strain of porcine reproductive and respiratory syndrome virus (prrsv) identified in canadian swine. | 2000 | 10857036 | |
| 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 |
| development of a recombinant nucleoprotein-based enzyme-linked immunosorbent assay for quantification of antibodies against porcine reproductive and respiratory syndrome virus. | a rapid, inexpensive enzyme-linked immunosorbent assay (elisa) to quantitate antibodies to porcine respiratory and reproductive syndrome virus (prrsv) in serum was developed using a recombinant prrsv nucleoprotein (rn). the sensitivity (85.3%) and specificity (81.7%) of the kansas state university elisa were good, correlating well (82.4%) with the idexx herdchek elisa. | 2000 | 10882676 |
| current knowledge on the structural proteins of porcine reproductive and respiratory syndrome (prrs) virus: comparison of the north american and european isolates. | porcine reproductive and respiratory syndrome virus (prrsv) belongs to the recently recognized arteriviridae family within the genus arterivirus, order nidovirales, which also includes equine arteritis virus (eav), lactate dehydrogenase-elevating virus (ldv), and simian hemorrhagic fever virus (shfv). mature viral particles are composed of an envelope 50-72 nm in diameter, with an isometric core about 20-30 nm enclosing a linear positive-stranded rna genome of approximately 15 kb. the virions ar ... | 2000 | 10893147 |
| evidence of porcine circovirus infection in pigs with wasting disease syndrome from 1985 to 1999 in hokkaido, japan. | an epizootiological survey with histopathological methods was conducted for porcine circovirus in 220 diseased pigs (1-200 days old) in 49 farms from 1985 to 1999. histopathological lesions containing pcv antigen were detected mainly in the lymphoid tissues from 42 of 189 diseased pigs (22.2%) in 4 of 45 farms (8.9%) from 1990 to 1999. the rate of positive pigs gradually increased from 1997 onward and pcv infection was found in 50% of diseased pigs in 1999. histopathologically, the lesions in th ... | 2000 | 10907690 |
| rapid detection of porcine reproductive and respiratory syndrome viral nucleic acid in blood using a fluorimeter based pcr method. | porcine reproductive and respiratory syndrome virus (prrsv) is an arterivirus recognised world wide as an important cause of reproductive failure and pneumonia in pigs. american and european strains of prrsv, differentiated antigenically and genomically, have been reported. prrsv infections are currently diagnosed using serology, virus isolation and/or immunocytochemistry. in order to overcome various drawbacks associated with these techniques, conventional, block-based rt-pcr methods for the de ... | 2000 | 10925037 |
| [porcine reproductive and respiratory syndrome round table discussion]. | 2000 | 10948601 | |
| preliminary characterization of protein binding factor for porcine reproductive and respiratory syndrome virus on the surface of permissive and non-permissive cells. | in its natural host, porcine reproductive and respiratory syndrome virus (prrsv) has been reported to have a restricted tropism for cells of the monocyte/macrophage lineage. to date, cloned monkey kidney cell lines, such as marc-145 and cl2621 cells which have been established from ma-104 cells, are the only non-porcine cells known to support prrsv replication. in the present study, a binding assay was set up to follow by flow cytometry the attachment of prrsv on the surface of porcine and non-p ... | 2000 | 10948985 |
| mutations in the genome of porcine reproductive and respiratory syndrome virus responsible for the attenuation phenotype. | 2000 | 10948988 | |
| [the discovery of the lelystad virus. a high point in dutch veterinary research during the last ten years (1990-1999)]. | 2000 | 10950729 | |
| effects of intranasal inoculation of porcine reproductive and respiratory syndrome virus, bordetella bronchiseptica, or a combination of both organisms in pigs. | to examine effects of co-infection with porcine reproductive and respiratory syndrome virus (prrsv) and bordetella bronchiseptica in pigs. | 2000 | 10951978 |
| production, characterization, and uses of monoclonal antibodies against porcine reproductive and respiratory syndrome virus 3' untranslated region and nucleoprotein rna binding proteins. | previous studies in our laboratory of interactions between the 3' untranslated region of porcine reproductive and respiratory syndrome virus (prrsv) and marc 145 cell cytoplasmic proteins have identified 11 rna binding proteins. here, we report the production and characterization of monoclonal antibodies (mabs) against a 67-kd rna binding protein of marc 145 tissue cultured cells. of the mabs produced, 11 were reactive in elisa with 67-kd protein. immunoprecipitation tests showed that six clones ... | 2000 | 10952415 |
| 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 |
| restriction fragment length polymorphism analysis of open reading frame 5 gene of porcine reproductive and respiratory syndrome virus isolates in korea. | the genetic variability of porcine reproductive and respiratory syndrome virus (prrsv) was studied by restriction fragment length polymorphism (rflp) of polymerase chain reaction (pcr)-amplified fragments among 50 korean isolates from open reading frame 5. all korean prrsvs were isolated from the field cases after the marketing of an u.s. atcc vr2332-derived modified live prrsv vaccine. combining the restriction enzyme digestion patterns obtained with mlui, hincii, sacii, and haeiii, we observed ... | 2000 | 10963352 |
| 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 |
| analysis of orf 1 in european porcine reproductive and respiratory syndrome virus by long rt-pcr and restriction fragment length polymorphism (rflp) analysis. | a rapid method was developed for partial characterization of the replicase-encoding open reading frame 1 (orf 1) of porcine reproductive and respiratory syndrome virus (prrsv). it comprised long rt-pcr amplification of 11.1 kb (94%) of orf 1, followed by restriction fragment length polymorphism analysis. the method was used to compare orf 1 sequences of two divergent european-type prrsv strains. our results indicated that the structural and replicase parts of these two strains had evolved at ove ... | 2000 | 10973697 |
| porcine reproductive and respiratory syndrome (prrs) virus down-modulates tnf-alpha production in infected macrophages. | the effect of porcine reproductive and respiratory syndrome (prrs) virus infection on the synthesis and secretion of tnf-alpha and other pro-inflammatory cytokines by porcine alveolar macrophages (pam) was investigated as well as the effect that tnf-alpha has on the replication of this virus. a clear reduction of phorbol myristate acetate (pma)-induced expression of tnf-alpha mrna was observed in cells incubated with prrs virus. moreover, the presence of prrs virus also induced a decrease in il- ... | 2000 | 10989184 |
| variations in the major envelope glycoprotein gp5 of czech strains of porcine reproductive and respiratory syndrome virus. | the major envelope glycoprotein genes (orf5) of seven czech isolates of porcine reproductive and respiratory syndrome virus (prrsv) were amplified and their nucleotide sequences were determined. orf5 displayed nucleotide and amino acid identities of 87.5-100% and 87. 6-100%, respectively, among the isolates. in a phylogenetic tree, all european isolates were grouped in a genotype distinct from that of reference american strains (vr-2332, iaf-klop). among the european isolates, two different clad ... | 2000 | 10993939 |
| antigenic variation and genotype of isolates of porcine reproductive and respiratory syndrome virus in korea. | a panel of three anti-glycoprotein 5 (gp5) protein monoclonal antibodies (mabs) (15, 28 and 246) and three anti-nucleocapsid (n) protein mabs (sdow17, vo17 and ep147) was used to investigate, by an indirect fluorescent antibody test, the antigenic variations of 50 korean isolates of porcine reproductive and respiratory syndrome virus (prrsv), and compare them with a us atcc vr2332-derived attenuated vaccine strain and the reference european lelystad strain of prrsv. a multiplex pcr assay for the ... | 2000 | 10994923 |
| comparison of serologic testing and slaughter evaluation for assessing the effects of subclinical infection on growth in pigs. | to compare serologic testing with slaughter evaluation in assessing effects of subclinical infection on average daily weight gain (adg) in pigs. | 2000 | 10997163 |
| 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 |
| a serological survey on classical swine fever (csf), aujeszky's disease (ad) and porcine reproductive and respiratory syndrome (prrs) virus infections in french wild boars from 1991 to 1998. | in early 1992, a csf epizootic was clinically recognised in a wild boar population of approximately 1300 animals within an area of 250km(2) located in the east of france. in order to check the csf situation in wild boars outside this area, a serological survey was carried out in the rest of france, for 8 consecutive years (1991-1998). this paper reports on the results obtained during this survey which included wild boars shot during the hunting period but also boars reared within fences. around ... | 2000 | 11042399 |
| porcine reproductive and respiratory syndrome virus: description of persistence in individual pigs upon experimental infection. | we studied the persistence of porcine reproductive and respiratory syndrome virus (prrsv) in individual experimentally infected pigs, during a period of up to 150 days postinfection (dpi). the results of this study suggest that the persistence of prrsv involves continuous viral replication but that it is not a true steady-state persistent infection. the virus eventually clears the body and seems to do it in most of the animals by 150 dpi or shortly thereafter. high genetic stability was seen for ... | 2000 | 11044133 |
| quantitative relationship of systemic virus concentration on growth and immune response in pigs. | ninety-six pigs from a herd naive for porcine reproductive and respiratory syndrome (prrs) virus were weaned (10 +/- 3 d of age), penned individually in isolation rooms, and, at 29 +/- 4 d of age, oronasally inoculated with a 2-ml dose of 10(4.3) ja142 prrs virus/ ml. body weight; feed intake; and serum concentrations of prrs virus, interferon, and alpha1-acylglycoprotein were determined for each pig every 4 d on d -8 to 24 postinoculation to quantify the effect of prrs exposure on the immune re ... | 2000 | 11048935 |
| comparison of virus isolation, reverse transcription-polymerase chain reaction, immunohistochemistry, and in situ hybridization for the detection of porcine reproductive and respiratory syndrome virus from naturally aborted fetuses and stillborn piglets. | virus isolation, reverse transcription-polymerase chain reaction (rt-pcr), immunohistochemistry, and in situ hybridization methods were compared for the detection of porcine reproductive and respiratory syndrome virus (prrsv). seven aborted fetuses and 6 stillborn piglets naturally infected with prrsv were used in the study. viral antigen and viral nucleic acid were detected in macrophages and dendritic cells in the spleen, tonsil, lymph nodes, and thymus; in macrophages of liver, heart, and lun ... | 2000 | 11108465 |
| 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 |
| influence of ampicillin, ceftiofur, attenuated live prrsv vaccine, and reduced dose streptococcus suis exposure on disease associated with prrsv and s. suis coinfection. | the objective of this research was to evaluate the efficacy of two antimicrobials (ampicillin and ceftiofur), a modified-live porcine reproductive and respiratory syndrome virus (prrsv) vaccine, and low dose exposure to streptococcus suis on disease associated with prrsv/s. suis coinfection. fifty-six, crossbred, prrsv-free pigs were weaned at 10-12 days of age and randomly assigned to five treatment groups. all pigs were inoculated with 2ml of 10(6.4) tcid50/ml of high virulence prrsv isolate v ... | 2001 | 11118739 |
| [porcine reproductive and respiratory syndrome--seminar]. | 2000 | 11125611 | |
| measurement of immunoglobulin g, a and m concentrations in boar seminal plasma. | how the immune system relates to the boar reproductive tract is not well defined. this is an important area of study because disease-causing agents may be transmitted through boar semen. we have previously identified porcine reproductive and respiratory syndrome virus (prrsv) in boar semen and wanted to identify prrsv-specific antibodies within seminal plasma. however, literature documenting total immunoglobulin concentration or the predominant immunoglobulin isotype in boar semen was not availa ... | 2000 | 11131334 |
| heteroclite subgenomic rnas are produced in porcine reproductive and respiratory syndrome virus infection. | porcine reproductive and respiratory syndrome virus (prrsv) was shown to produce atypical subgenomic rnas that contain open reading frame la nucleotides and are present under a wide variety of culture conditions, including high and low multiplicities of infection, in simian and porcine host cells, and during infection with cell-adapted and wild-type prirsv strains. sequence analysis demonstrated that they are heterogeneous in 5-3' junction sequence and size and may code for different predicted f ... | 2000 | 11183205 |
| evidence for the localization of porcine reproductive and respiratory syndrome virus (prrsv) antigen and rna in ovarian follicles in gilts. | the pathogenesis of porcine reproductive and respiratory syndrome virus (prrsv) infection in ovary was studied in sexually mature, cycling, nonsynchronized gilts infected with the prrsv 16244b, a virulent field strain. previous studies have shown that prrsv can be isolated from ovaries and is transplacentally passed from gilts to the fetuses. the cause of infertility following prrsv infection is not known. in this study, we identified the tropism of prrsv in ovarian tissue from experimentally in ... | 2001 | 11199165 |
| full-length sequence of a canadian porcine reproductive and respiratory syndrome virus (prrsv) isolate. | presently, one of the most economically important pathogens affecting swine is the porcine reproductive and respiratory syndrome virus (prrsv). this virus is prevalent in herds throughout the world and continues to pose a significant threat as newer and more virulent disease phenotypes emerge. in this report we describe the full-length nucleotide sequence of a canadian prrsv isolate, designated pa8. a consecutive sequence of 15,411 nucleotides was obtained from a set of overlapping cdna clones. ... | 2000 | 11205119 |
| experimental infection of colostrum deprived piglets with porcine circovirus 2 (pcv2) and porcine reproductive and respiratory syndrome virus (prrsv) potentiates pcv2 replication. | experimental infection of colostrum-deprived (cd) pigs with a combined inoculum of porcine circovirus 2 (pcv2) and porcine reproductive and respiratory syndrome virus (prrsv) potentiated the replication and distribution of pcv2 virus, when compared with pigs inoculated with pcv2 alone. the replication and distribution of prrsv in dually infected pigs was not enhanced, when compared to pigs inoculated with prrsv alone. the mechanisms involved in the potentiation of pcv2 replication in pcv2/prrsv ... | 2000 | 11205128 |
| complete genome comparison of porcine reproductive and respiratory syndrome virus parental and attenuated strains. | two full-length porcine reproductive and respiratory syndrome virus (prrsv) genomes, strain vr-2332 and its cell culture passaged descendent respprrs vaccine strain, were compared and analyzed in order to identify possible sites of attenuation. of the 44 nucleotide changes, 13 resulted in conservative changes and 18 produced non-conservative changes. the results suggest that key amino acids in orf1 may contribute to the phenotype of respprrs, which includes increased growth rate on ma-104 cells ... | 2001 | 11226578 |
| an evaluation of test and removal for the elimination of porcine reproductive and respiratory syndrome virus from 5 swine farms. | the objective of this field study was to evaluate the protocol of test and removal (t&r) for the elimination of porcine reproductive and respiratory syndrome virus (prrsv) from 5 chronically infected breeding herds. the t&r protocol involved sampling the entire breeding herd in one day, testing sera by polymerase chain reaction and elisa to detect previously exposed and/or infected animals, and subsequently removing them from the herd. following completion of t&r, breeding herds were monitored f ... | 2001 | 11227190 |
| epitope mapping porcine reproductive and respiratory syndrome virus by phage display: the nsp2 fragment of the replicase polyprotein contains a cluster of b-cell epitopes. | we screened phage display libraries of porcine reproductive and respiratory syndrome virus (prrsv) protein fragments with sera from experimentally infected pigs to identify linear b-cell epitopes that are commonly recognized during infection in vivo. we identified 10 linear epitope sites (es) 11 to 53 amino acids in length. in the replicase polyprotein, a total of eight es were identified, six of which localized to the nsp2 replicase polyprotein processing end product. in the structural proteins ... | 2001 | 11238854 |
| double in situ hybridization for simultaneous detection of porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus (pcv). | a double in situ hybridization method for the simultaneous detection of porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus (pcv) genomes in the same tissue section was applied to lung tissues from 9 pigs in which prrsv and pcv coinfection had been previously demonstrated. paraffin-embedded tissue sections were simultaneously hybridized with a digoxigenin-labeled antisense rna probe for prrsv and a fluorescein-labeled antisense rna probe for pcv, and hybridization ... | 2001 | 11243366 |
| detection and duration of porcine reproductive and respiratory syndrome virus in semen, serum, peripheral blood mononuclear cells, and tissues from yorkshire, hampshire, and landrace boars. | because transmission of porcine reproductive and respiratory syndrome virus (prrsv) can occur through boar semen, it is important to identify persistently infected boars. however, even for boars given the same prrsv strain and dose, variability in the duration of viral shedding in semen has been observed, suggesting that host factors are involved in prrsv persistence. to determine whether there are host genetic factors, particularly litter and breed differences related to the persistence of prrs ... | 2001 | 11289209 |
| identification of an immunodominant epitope in the c terminus of glycoprotein 5 of porcine reproductive and respiratory syndrome virus. | glycoprotein 5 (gp(5)) is the major glycoprotein of porcine reproductive and respiratory syndrome virus (prrsv). expression of gp(5) has been improved by removing the transmembrane regions. vectors were constructed encoding complete gp(5) plus three mutants: gp(5) ns (residues 28--201), gp(5)[30--67] (residues 30--67) and gp(5)[30--201] (residues 30--67/130--201). the three deletion mutants were expressed at levels 20--30 times higher than complete gp(5). gp(5)[30--201] was well recognized in el ... | 2001 | 11297674 |
| in utero infection by porcine reproductive and respiratory syndrome virus is sufficient to increase susceptibility of piglets to challenge by streptococcus suis type ii. | porcine reproductive and respiratory syndrome (prrs) consistently elevates the frequency of disease and mortality in young pigs. many different secondary bacterial diseases occur in prrs virus (prrsv)-infected pigs. however, to date, establishing a reproducible experimental model of prrsv infection in weaned pigs, with subsequent clinical disease following secondary bacterial challenge, has been difficult. prrsv is frequently isolated during outbreaks from weak-born piglets affected by secondary ... | 2001 | 11312360 |
| large envelope glycoprotein and nucleocapsid protein of equine arteritis virus (eav) induce an immune response in balb/c mice by dna vaccination; strategy for developing a dna-vaccine against eav-infection. | equine arteritis virus (eav) is a member of the arteriviridae family, that includes lactate dehydrogenase-elevating virus (ldv), porcine reproductive and respiratory syndrome virus (prrsv), and simian haemorrhagic fever virus (shfv). equine arteritis is a contagious disease of horses and is spread via respiratory or reproductive tract. the objective of the present study is to evaluate the possibility for developing a model system for prevention horses against an eav infection by dnavaccination. ... | 2001 | 11324756 |
| comparison of the 5' leader sequences of north american isolates of reference and field strains of porcine reproductive and respiratory syndrome virus (prrsv). | the 5' leader is documented to be an important regulatory element in many (+) ssrnavirus genome. to understand the significance of the 5' leader rna of prrsv, we determined the complete leader sequences of fifteen different north american strains of prrsv and predicted their secondary structures. viruses analysed included three reference strains and nine field strains originating from different geographic locations. to further examine the leader region, one of the field strains was adapted to gr ... | 2001 | 11324758 |
| effects of intranasal inoculation with bordetella bronchiseptica, porcine reproductive and respiratory syndrome virus, or a combination of both organisms on subsequent infection with pasteurella multocida in pigs. | to determine effects of intranasal inoculation with porcine reproductive and respiratory syndrome virus (prrsv) or bordetella bronchiseptica on challenge with nontoxigenic pasteurella multocida in pigs. | 2001 | 11327458 |
| antigenic importance of the carboxy-terminal beta-strand of the porcine reproductive and respiratory syndrome virus nucleocapsid protein. | five domains of antigenic importance were previously mapped on the nucleocapsid protein (n) of the porcine reproductive and respiratory syndrome virus (prrsv), and a domain comprised of the 11 c-terminal-most amino acids (residues 112 to 123) was shown to be essential for binding of n-specific conformation-dependent monoclonal antibodies (mabs). in the present study, the importance of individual residues within this c-terminal domain for antigenicity was investigated using eight different mutant ... | 2001 | 11329465 |
| inhibition of porcine reproductive and respiratory syndrome virus by interferon-gamma and recovery of virus replication with 2-aminopurine. | porcine reproductive and respiratory syndrome virus (prrsv) belongs to a group of rna viruses that establish persistent infections. a proposed strategy for evading immunity during persistent prrsv infection is by preventing the induction of ifn activity in pigs and/or by blocking the activation of antiviral proteins in permissive cells. ifn-gamma mrna expression was observed in the lymph nodes and lungs of pigs infected with wild-type prrsv strain sdsu-23983. pretreatment of marc-145 cells with ... | 2001 | 11338389 |
| proliferative vasculopathy and cutaneous hemorrhages in porcine neonates infected with the porcine reproductive and respiratory syndrome virus. | severe cutaneous hemorrhages with dermal and subcutaneous capillary angioplasia were seen in aborted and stillborn piglets, concurrently with an acute outbreak of porcine reproductive and respiratory syndrome virus (prrsv) abortions. histologically, the lesions consisted of angioblastic endothelial cells and immature capillary vascular structures coursing through the edematous myxomatous dermis and subcutis. proliferating capillaries often were surrounded by large and foamy macrophages that stai ... | 2001 | 11355668 |
| differential production of proinflammatory cytokines: in vitro prrsv and mycoplasma hyopneumoniae co-infection model. | an in vitro culture system was developed to investigate the induction of proinflammatory cytokines by mycoplasma hyopneumoniae and porcine reproductive and respiratory syndrome virus (prrsv). m. hyopneumoniae infected porcine tracheal ring explants were co-cultured with prrsv infected pulmonary alveolar macrophages (pams) for 24h to assess the cytokine production of each pathogen alone and the interaction between the two pathogens in vitro. semiquantitative rt-pcr was used to measure interleukin ... | 2001 | 11356254 |
| increased proteolytic activity and matrix metalloprotease expression in lungs during infection by porcine reproductive and respiratory syndrome virus. | the local increase in the secretion of extracellular proteases, allowing cleavage of the extracellular matrix and thereby facilitating the infiltration of t cells, monocytes and neutrophils, is a hallmark of chronic inflammation and autoimmunity. in pulmonary genetic diseases, such as emphysema and cystic fibrosis, proteases can also favour the development of local immunodeficiency by degrading key regulators of the immune response, such as cd4, cd8, igg, icam-1 and c3b receptors. since several ... | 2001 | 11369868 |
| reversion of a live porcine reproductive and respiratory syndrome virus vaccine investigated by parallel mutations. | a live attenuated porcine reproductive and respiratory syndrome (prrs) vaccine virus has been shown to revert to virulence under field conditions. in order to identify genetic virulence determinants, orf1 from the attenuated vaccine virus and three danish vaccine-derived field isolates was sequenced and compared with the parental strain of the vaccine virus (vr2332). this revealed five mutations that had occurred independently in all three vaccine-derived field isolates, indicating strong parall ... | 2001 | 11369869 |
| generation and mapping of expressed sequence tags from virus-infected swine macrophages. | in an effort to identify genes that have a major effect on macrophage function during viral infection, we employed differential display reverse transcription (ddrt)-pcr to capture expressed sequence tags (ests) of swine alveolar macrophages infected by the porcine reproductive and respiratory syndrome virus (prrsv). sequence analyses showed that approximately 60% of these ests had significant similarity (> or =93%) to known pig ests or genes or matched sequences from other species with homology ... | 2001 | 11370681 |
| the effect of dietary soy genistein on pig growth and viral replication during a viral challenge. | twelve replications of four littermate pigs from a herd naive for porcine reproductive and respiratory syndrome (prrs) were weaned (10 +/- 2 d of age) and penned individually in isolation rooms. pigs were randomly allotted within litter to one of four dietary soy genistein concentrations (0, 200, 400, and 800 ppm) to quantify the effect of soy genistein on pig growth and virus replication during a viral challenge. genistein was provided as the soy glycoside, genistin. at 29 +/- 2 d of age (4.9 + ... | 2001 | 11374547 |
| semen from boars infected with porcine reproductive and respiratory syndrome virus (prrsv) contains antibodies against structural as well as nonstructural viral proteins. | the seminal excretion of antibodies against porcine reproductive and respiratory syndrome virus (prrsv) was examined in a group of five boars experimentally infected by the nasopharyngeal route. by using phage-displayed peptide epitopes from the prrsv replicase and envelope glycoproteins as elisa antigen, we were able to separately and specifically assay antibody responses against structural and nonstructural viral proteins. antibodies against structural as well as nonstructural viral proteins w ... | 2001 | 11376957 |
| a quantitative assessment of the effectiveness of prrsv vaccination in pigs under experimental conditions. | this paper presents a quantitative approach to evaluate effectiveness of vaccination under experimental conditions. we used two consecutive experimental designs to investigate whether prrsv transmission among vaccinated pigs was reduced compared to control pigs and to estimate the reproduction parameter r. based upon data analysis and power calculations the series of small-scale vaccination-challenge experiments ended with multiple one-to-one experiments. this new experimental design has conside ... | 2001 | 11395197 |
| sequence analysis of the membrane protein gene and nucleocapsid gene of porcine reproductive and respiratory syndrome virus isolated from a swine herd in hungary. | porcine reproductive and respiratory syndrome virus (prrsv) was isolated from blood samples taken at a pig farm in hungary from pigs showing clinical signs of the disease. the virus (abv 32) was identified as belonging to the european genotype by using type-specific monoclonal antibodies. this was confirmed by comparing the sequence of the membrane protein gene (orf 6) and the nucleocapsid gene (orf 7) with the american vr2332 and the european lv genotype reference strain, respectively. analysis ... | 2001 | 11402653 |
| polymerase chain reaction-based restriction fragment length polymorphism pattern of porcine reproductive and respiratory syndrome virus directly from lung tissues without virus isolation in korea. | polymerase chain reaction (pcr)-based restriction fragment length polymorphism (rflp) analysis was developed for directly typing porcine reproductive and respiratory syndrome virus (prrsv) from lung specimens without virus isolation. twenty nine lung specimens collected from postweaning pigs were isolated for prrsv. when the pcr products from the 29 lung specimens were digested by the restriction enzymes mlui, hincii, sacii and haeiii, the rflp patterns from the 29 lung specimens matched with th ... | 2001 | 11411506 |
| diagnostic investigation of chronic porcine reproductive and respiratory syndrome virus in a breeding herd of pigs. | forty-five sows and 15 boars were selected at random from a breeding herd known to be chronically infected with porcine reproductive and respiratory syndrome virus (prrsv) and lymphoid, immune-privileged, and non-lymphoid/non-immune-privileged tissues were tested for the presence of the virus by pcr, virus isolation, and immunohistochemistry. the virus was isolated from the lateral retropharyngeal lymph node of one sow; the isolate was nucleic acid sequenced and determined to be of field origin, ... | 2001 | 11425255 |
| interaction between mycoplasma hyopneumoniae and swine influenza virus. | an experimental respiratory model was used to investigate the interaction between mycoplasma hyopneumoniae and swine influenza virus (siv) in the induction of pneumonia in susceptible swine. previous studies demonstrated that m. hyopneumoniae, which produces a chronic bronchopneumonia in swine, potentiates a viral pneumonia induced by the porcine reproductive and respiratory syndrome virus (prrsv). in this study, pigs were inoculated with m. hyopneumoniae 21 days prior to inoculation with siv. c ... | 2001 | 11427564 |
| posttransplant lymphoproliferative disorder after liver transplantation in miniature swine. | posttransplant lymphoproliferative disorder (ptld) is a well-known, life-threatening complication of immunosuppressive therapy, occurring in both adult and pediatric transplant recipients. | 2001 | 11435984 |
| distribution of porcine reproductive and respiratory syndrome virus in stillborn and liveborn piglets from experimentally infected sows. | four pregnant sows were infected 3 weeks before their expected farrowing date with a korean isolate (north american genotype) of porcine reproductive and respiratory syndrome virus (prrsv). the distribution of virus in their stillborn and liveborn (killed 7 days after birth) offspring was assessed immunohistochemically and by in-situ hybridization. prrsv antigen and nucleic acid were detected in lung, thymus, liver, tonsil, spleen, heart, kidney and lymph nodes from both stillborn and liveborn p ... | 2001 | 11437498 |
| detection of european porcine reproductive and respiratory syndrome virus in porcine alveolar macrophages by two-colour immunofluorescence and in-situ hybridization-immunohistochemistry double labelling. | two groups of five pigs aged 6 weeks were each infected oronasally with one of two different european isolates of porcine reproductive and respiratory syndrome virus (prrsv). the animals were killed sequentially at 4, 7, 14 or 21 days post-inoculation for examination. the methods used consisted of histopathology, and mono- and double-labelling techniques based on in-situ hybridization, immunofluorescence and immunohistochemistry. porcine alveolar macrophages (pams) contained large amounts of prr ... | 2001 | 11437499 |
| colocalization of porcine reproductive and respiratory syndrome virus and porcine circovirus 2 in porcine dermatitis and nephrology syndrome by double-labeling technique. | simultaneous detection of porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus 2 (pcv2) was achieved by a double-labeling technique using a combination of immunohistochemistry and in situ hybridization in five pigs with naturally occurring porcine dermatitis and nephropathy syndrome (pdns). both prrsv and pcv2 were isolated from a homogenate of pooled skin and kidney from three pigs. prrsv rna was demonstrated by reverse transcription polymerase chain reaction (pcr) ... | 2001 | 11467478 |
| comparison of porcine reproductive and respiratory syndrome virus growth in media supplemented with fetal bovine serum or a serum replacement. | commercially available serum replacements are often used in cell culture as a cheaper and less variable substitute for fetal bovine serum (fbs). the growth of porcine reproductive and respiratory syndrome virus (prrsv) isolates in crl11171 cells maintained in a medium supplemented with fbs was compared with virus propagation in the same cell line maintained in the same medium with a serum replacement. the prrsv replicated significantly better when the cell culture medium was supplemented with fb ... | 2001 | 11482613 |
| changes in peripheral blood leukocyte populations in pigs with natural postweaning multisystemic wasting syndrome (pmws). | the objective of the present study was to analyze, by flow cytometry, changes in pbmc subsets in pigs having postweaning multisystemic wasting syndrome (pmws), a new condition associated to porcine circovirus type 2 (pcv2) infection. thirteen acutely pmws affected pigs were selected from a farm seronegative to porcine reproductive and respiratory syndrome virus (prrsv) and to aujeszky's disease virus (adv); 11 clinically healthy pigs were selected from a high health farm with no history of pmws ... | 2001 | 11498245 |
| a 10-kda structural protein of porcine reproductive and respiratory syndrome virus encoded by orf2b. | the major structural proteins of porcine reproductive and respiratory syndrome virus (prrsv) are derived from orfs 5, 6, and 7. western blots of sucrose gradient-purified virions and prrsv-infected marc-145 cells, probed with immune pig serum, showed the presence of an additional 10-kda protein. nucleotide sequence analysis of north american prrsv isolate sdsu-23983 revealed a small orf within orf2, named orf2b, which, when translated, produced a 73-amino-acid nonglycosylated protein. recombinan ... | 2001 | 11504553 |
| quantitative taqman rt-pcr for the detection and differentiation of european and north american strains of porcine reproductive and respiratory syndrome virus. | since two different types of porcine reproductive and respiratory syndrome virus (prrsv), the european (eu) and the north american (us) strain, occur or coexist in european swine herds, their rapid and reliable detection and differentiation is essential for disease surveillance. a quantitative taqman reverse transcription-polymerase chain reaction (rt-pcr) is described for prrsv detection and strain differentiation. sensitivity and specificity were compared with a conventional prrsv rt-pcr and t ... | 2001 | 11543885 |
| complete genome comparison of porcine reproductive and respiratory syndrome virus parental and attenuated strains. | two full-length porcine reproductive and respiratory syndrome virus (prrsv) genomes, strain vr-2332 and its cell culture passaged descendent respprrs vaccine strain, were compared and analyzed in order to identify possible sites of attenuation. of the 41 nucleotide changes, 12 resulted in conservative changes and 18 produced non-conservative changes. the results suggest that key amino acids in orf1 may contribute to the phenotype of respprrs, which includes increased growth rate on ma-104 cells ... | 2001 | 11551659 |
| experimental reproduction of severe disease in cd/cd pigs concurrently infected with type 2 porcine circovirus and porcine reproductive and respiratory syndrome virus. | three-week-old cesarean-derived colostrum-deprived (cd/cd) pigs were inoculated with porcine circovirus type 2 (pcv2, n = 19), porcine reproductive and respiratory syndrome virus (prrsv, n = 13), concurrent pcv2 and prrsv (pcv2/prrsv, n = 17), or a sham inoculum (n = 12) to compare the independent and combined effects of these agents. necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. by 10 dpi, pcv2/prrsv-inoculated pigs had severe dy ... | 2001 | 11572560 |
| genetic variation and phylogenetic analyses of the orf5 gene of acute porcine reproductive and respiratory syndrome virus isolates. | swine herds in the us have experienced recent outbreaks of a severe form of porcine reproductive and respiratory syndrome (designated acute or atypical prrs) characterized by abortion and high mortality in pregnant sows. most of the affected herds had been vaccinated with modified live-vaccines (mlvs) against prrs. to explore the possible mechanism of the emergence of acute prrs, the open reading frame 5 (orf5) gene encoding the major envelope protein (gp5) of acute prrsv isolates was characteri ... | 2001 | 11574173 |
| polyclonal activation of b cells occurs in lymphoid organs from porcine reproductive and respiratory syndrome virus (prrsv)-infected pigs. | porcine reproductive and respiratory syndrome virus (prrsv) induces a persistent viral infection associated with an inefficient humoral immune response. a study of lymphoid b cells and specific humoral immune response was performed in blood and several lymphoid organs collected from prrsv experimentally-infected pigs. groups of specific pathogen-free (spf) pigs were infected with the lhva-93-3 isolate of prrsv, and blood, tonsils, spleen and mediastinal lymph nodes (mln) were collected at variou ... | 2001 | 11587732 |
| monitoring porcine reproductive and respiratory syndrome virus infection status in swine herds based on analysis of antibodies in meat juice samples. | an indirect elisa test was developed as a novel tool aimed at monitoring the herd infection status of swine herds. meat juice samples from pig carcasses were analysed for the presence of antibodies against porcine reproductive and respiratory syndrome virus (prrsv). a study of samples from herds with known prrs status was undertaken. the prrs status of the herds was evaluated based on the analysis of blood samples by another serological test (blocking elisa) capable of differentiating between in ... | 2001 | 11592614 |
| clinical and pathological observations on pigs with postweaning multisystemic wasting syndrome. | the aim of this work was to characterise the lesions and agents present in clinically normal and clinically affected pigs on a farm during an outbreak of postweaning multisystemic wasting syndrome (pmws), and to evaluate the diagnostic techniques for detecting porcine circovirus type 2 (pcv-2) and other microorganisms. four pigs in the early stage and 11 pigs in the late stage of the disease, and eight clinically normal pigs were necropsied. samples of lymphoid tissue and serum were also obtaine ... | 2001 | 11594382 |
| construction of chimeric arteriviruses reveals that the ectodomain of the major glycoprotein is not the main determinant of equine arteritis virus tropism in cell culture. | the recent development of arterivirus full-length cdna clones makes possible the construction of chimeric arteriviruses for fundamental and applied studies. using an equine arteritis virus (eav) infectious cdna clone, we have engineered chimeras in which the ectodomains of the two major envelope proteins, the glycoprotein gp(5) and the membrane protein m, were replaced by sequences from envelope proteins of related and unrelated rna viruses. using immunofluorescence microscopy, we monitored the ... | 2001 | 11601900 |
| 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 |
| high frequency rna recombination in porcine reproductive and respiratory syndrome virus occurs preferentially between parental sequences with high similarity. | two types of porcine reproductive and respiratory syndrome virus (prrsv) exist, a north american type and a european type. the co-existence of both types in some countries, such as denmark, slovakia and canada, creates a risk of inter-type recombination. to evaluate this risk, cell cultures were co-infected with either a north american and a european type of prrsv or two diverse types of european isolate. subsequently, an approximately 600 bp region of the prrsv genome was tested for recombinati ... | 2001 | 11602772 |
| effect of porcine reproductive and respiratory syndrome virus infection on the ovary and progesterone levels in third trimester pregnant sows. | porcine reproductive and respiratory syndrome virus (prrsv) is a common cause of reproductive failure and abortion in swine. the mechanism of abortion is not fully defined, and the effect of the virus on luteal function has not been explored. in this study, we exposed late-term pregnant swine to varied doses of prrsv strain nadc-8 and evaluated effects on ovarian function by serial determination of plasma progesterone levels and by microscopic evaluation of ovarian pathologic alterations combine ... | 2001 | 11665881 |
| a molecular clock dates the common ancestor of european-type porcine reproductive and respiratory syndrome virus at more than 10 years before the emergence of disease. | the disease caused by porcine reproductive and respiratory syndrome virus (prrsv) emerged independently and almost simultaneously in europe (1990) and north america (1987). the original reservoir of the virus and the date it entered the pig populations is not known. in this study, we demonstrate an accurate molecular clock for the european prrsv orf 3 gene, place the root in the genealogy, estimate the rate of nucleotide substitution, and date the most recent common viral ancestor of the data se ... | 2001 | 11689039 |
| immunology of the porcine respiratory disease complex. | prdc is a multifactorial respiratory syndrome that includes several respiratory pathogens. as can be observed in this article, although the pathogenesis of some of the respiratory pathogens of pigs is fairly well defined, the host response and the immune response necessary to control the pathogen often remain unclear. as our ability to evaluate the porcine immune system and its ability to respond to disease improves, the knowledge of how each of these respiratory pathogens alter and evade the im ... | 2001 | 11692508 |
| the role of pulmonary intravascular macrophages in porcine reproductive and respiratory syndrome virus infection. | the objective of this article is to summarize the current state of knowledge of the complex interaction of porcine reproductive and respiratory syndrome virus (prrsv) and porcine pulmonary intravascular macrophages (pims). pims play an important role in pulmonary surveillance, and in the past few years we have investigated their role in prrsv infection. prrsv antigens and nucleic acids have been demonstrated in pims both in vitro and in vivo. examination of cultured pims infected with prrsv reve ... | 2000 | 11708601 |
| evaluation of conjugated linoleic acid and dietary antibiotics as growth promotants in weanling pigs. | an experiment was conducted to determine the efficacy of dietary conjugated linoleic acid (cla) as a growth promotant in weanling swine. weanling pigs (n = 192; 7.6 kg and 29 d of age) were randomly assigned to four treatments that were arranged as a 2 x 2 factorial. concentrations of dietary cla (0 or 0.6%) and antibiotics (+/-) constituted the main effect variables. dietary cla treatments consisted of a 1% addition of an oil containing 60% cla isomers or 1% soybean oil, and dietary antibiotic ... | 2001 | 11721832 |
| experimental inoculation of late term pregnant sows with a field isolate of porcine reproductive and respiratory syndrome vaccine-derived virus. | the use of a live attenuated porcine reproductive and respiratory syndrome virus (prrsv) vaccine in piglets has been associated with reproductive disorders in non-vaccinated sows. vaccine-derived virus (vdv) has been isolated from foetuses, stillborn pigs, and dead piglets, indicating that the live vaccine spread from vaccinated piglets to non-vaccinated sows, and that the virus might be implicated in the severe reproductive problems observed. in the present study, one such vdv isolate was used ... | 2002 | 11731155 |