| diversity and evolution of a newly emerged north american type 1 porcine arterivirus: analysis of isolates collected between 1999 and 2004. | european-like type 1 porcine reproductive and respiratory syndrome virus (prrsv) isolates, known as north american (na) type 1 prrsv, appeared in united states (u.s.) swine herds in 1999. their diversity and evolution were studied over a five-year period by constructing phylogenetic trees using nsp2 and orf5 sequences of 20 na type 1 isolates, including the only known isolate from hawaii. all but two of the isolates possessed the same 51-nt deletion in nsp2, suggesting a clonal origin. parsimony ... | 2007 | 17323198 |
| recombinant swine beta interferon protects swine alveolar macrophages and marc-145 cells from infection with porcine reproductive and respiratory syndrome virus. | swine beta interferon (swifn-beta) produced in hek 293 cells infected with a recombinant, replication-defective human adenovirus 5 (ad5) encoding the swifn-beta gene was tested for antiviral activity against porcine reproductive and respiratory syndrome virus (prrsv). marc-145 cells were incubated overnight with dilutions of supernatant fluids from hek 293 cells infected with ad5-swifn-beta or with an ad5 control virus (ad5-blue). treated cells were infected with prrsv; marc-145 cells incubated ... | 2007 | 17325366 |
| direct inoculation of rna transcripts from an infectious cdna clone of porcine reproductive and respiratory syndrome virus (prrsv) into the lymph nodes and tonsils of pigs initiates prrsv infection in vivo. | the recent construction of prrsv infectious cdna clones affords the opportunity for structural and functional studies of prrsv genes. however, the inherent instability of the prrsv genome, the requirement of cell culture propagation, and poor virus recovery have limited the usefulness of the prrsv reverse genetics system for in vivo studies. here, we report a unique strategy of infecting pigs by bypassing the traditional in vitro cell culture step required for in vivo studies. we demonstrate tha ... | 2007 | 17361326 |
| [influence of epitope a modification and n-linked glycosylated site mutation of prrsv nj-a strain orf5 gene on the ability to induce neutralizing antibodies and t cell proliferation response]. | to enhance the dna immunogencity of prrsv orf5 gene, cpg sequence and the universal helper t cell antigen epitope (padre) sequence were inserted between the decoy epitope and the neutralizing epitope. at the same time, site-mutations were introduced at n33 and n51 to diminish the coverage effect to epitope b from the polysaccharides. subsequently, the modified orf5 gene (morf5) and prrsv orf6 gene were cloned into the eukaryotic expression vector pcdna3.0 under the control of two cmv promoters, ... | 2007 | 17366885 |
| cross-reactive antibody responses to nsp1 and nsp2 of porcine reproductive and respiratory syndrome virus. | porcine reproductive and respiratory syndrome virus (prrsv) non-structural proteins (nsps) play a key role in processing and maturation of the repertoire of structural and nsps of the virion, but little is known about the anti-nsp immune response. here, it was hypothesized that pronounced antibody responses are generated to prrsv nsp1 and nsp2, as they are present in infected cells and cytolytic infection releases viral proteins into interstitial spaces. accordingly, nsp1 and nsp2 were cloned an ... | 2007 | 17374762 |
| 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 |
| genetic diversity and phylogenetic analysis of glycoprotein 5 of prrsv isolates in mainland china from 1996 to 2006: coexistence of two na-subgenotypes with great diversity. | gp5, the most important neutralizing antigen of porcine reproductive and respiratory syndrome virus (prrsv), has the highest genetic diversity among isolates. to more fully understand the extent of genetic diversity of prrsv in china, we analyzed and compared the gp5 sequences of 42 prrsv isolated from 1996 to 2006 in mainland china. we found that all of the chinese isolates examined belong to the north american (na) type. among them two highly diverse subgroups were clearly demarcated on the na ... | 2007 | 17383833 |
| advances in swine biomedical model genomics. | this review is a short update on the diversity of swine biomedical models and the importance of genomics in their continued development. the swine has been used as a major mammalian model for human studies because of the similarity in size and physiology, and in organ development and disease progression. the pig model allows for deliberately timed studies, imaging of internal vessels and organs using standard human technologies, and collection of repeated peripheral samples and, at kill, detaile ... | 2007 | 17384736 |
| monoclonal antibody and porcine antisera recognized b-cell epitopes of nsp2 protein of a chinese strain of porcine reproductive and respiratory syndrome virus. | porcine reproductive and respiratory syndrome virus (prrsv) is one of the most economically important pathogens for swine industry. the non-structural protein 2 (nsp2) is considered to be one of the immunogenic proteins of prrsv. in this study, the b-cell epitopes of the nsp2 protein of a north american type chinese strain prrsv bj-4 were identified on a prokaryotic expressed nsp2 fragment (73-567aa). a total of six monoclonal antibodies (mabs) recognizing different epitopes on the expressed pro ... | 2007 | 17416435 |
| immune responses of pigs inoculated with a recombinant fowlpox virus coexpressing gp5/gp3 of porcine reproductive and respiratory syndrome virus and swine il-18. | two recombinant fowlpox viruses (rfpv-orf5-orf3 and rfpv-il-18-orf5-orf3) containing the orf5/orf3 cdnas of prrsv (strain chang chun) and il-18 of swine were constructed and evaluated for theirs abilities to induce humoral and cellular responses in piglets. in addition, their abilities to protect piglets against homologous virus challenge were examined. all piglets were given booster vaccinations at 21 days after the initial inoculation, and all piglets were challenged at 60 after the initial in ... | 2007 | 17418456 |
| québec. isolation of the porcine reproductive and respiratory syndrome virus in québec. | | 1992 | 17424067 |
| innate immune responses to replication of porcine reproductive and respiratory syndrome virus in isolated swine alveolar macrophages. | porcine reproductive and respiratory syndrome (prrs) is an infectious disease caused by a positive rna strand arterivirus. prrs virus (prrsv) interacts primarily with lung macrophages. identifying the genetic components involved in host resistance/susceptibility would represent an important step forward in the design of disease control programs. in this study, alveolar macrophages derived from five commercial pig lines were used to study the innate immune response to prrsv infection in vitro. an ... | 2007 | 17425425 |
| impact of a modified-live porcine reproductive and respiratory syndrome virus vaccine intervention on a population of pigs infected with a heterologous isolate. | the objectives of this study were to evaluate the effects of a therapeutic vaccine intervention with a modified-live porcine reproductive and respiratory syndrome virus (prrsv) vaccine on the dynamics of a heterologous viral infection in a population of pigs, and to determine the clinical and virological response of previously exposed and vaccinated pigs against a second virulent heterologous challenge. a population of 320 pigs were infected with a field isolate, prrsv mn-30100, alone or followe ... | 2007 | 17451850 |
| structure of the equine arteritis virus nucleocapsid protein reveals a dimer-dimer arrangement. | equine arteritis virus (eav) is an enveloped positive-sense rna virus belonging to the arteriviridae family, which also includes the porcine pathogen prrsv and is genetically and structurally related to the coronaviruses. eav is an important equine pathogen that has caused significant economic losses to the horse-breeding industry and has been difficult to control. the eav virion consists of a genome-containing nucleocapsid core made of nucleocapsid (n) protein surrounded by a lipid envelope con ... | 2007 | 17452783 |
| effect of genotypic and biotypic differences among prrs viruses on the serologic assessment of pigs for virus infection. | genetic, antigenic, and pathogenic variability is known to exist among porcine reproductive and respiratory syndrome (prrs) viruses and has garnered great attention for diagnostics and disease control/prevention. a comparative serologic study was conducted on five field and two cell-attenuated viruses to determine if serologic responses to prrs virus infection could be influenced by biotypic and/or genotypic differences of the viruses. the isolates used for the study varied in their virulence to ... | 2007 | 17467931 |
| differential immunity in pigs with high and low responses to porcine reproductive and respiratory syndrome virus infection. | one hundred hampshire x duroc cross-bred pigs (hd) and 100 ne index line (i) pigs were infected with porcine reproductive and respiratory syndrome (prrs) virus and evaluated for resistance/susceptibility. controls (100/line) were uninfected littermates to the infected pigs. viremia, change in weight (wtdelta), and rectal temperature at 0, 4, 7, and 14 d postinfection were recorded. lung, bronchial lymph node (bln), and blood tissue were collected at necropsy (14 d postinfection). the first princ ... | 2007 | 17468430 |
| effect of vaccination with a modified-live porcine reproductive and respiratory syndrome virus vaccine on dynamics of homologous viral infection in pigs. | to determine effects of vaccination protocols with modified-live porcine reproductive and respiratory syndrome virus (prrsv) vaccine on persistence and transmission of virus in pigs infected with a homologous isolate and determine clinical and virologic responses following heterologous viral challenge. | 2007 | 17472459 |
| antibody repertoire development in fetal and neonatal piglets: xix. undiversified b cells with hydrophobic hcdr3s preferentially proliferate in the porcine reproductive and respiratory syndrome. | porcine respiratory and reproductive syndrome virus (prrsv) causes an extraordinary increase in the proportion of b cells resulting in lymphoid hyperplasia, hypergammaglobulinemia, and autoimmunity in neonatal piglets. spectratypic analysis of b cells from neonatal isolator piglets show a non-gaussian pattern with preferential expansion of clones bearing certain h chain third complementary region (hcdr3) lengths. however, only in prrsv-infected isolator piglets was nearly the identical spectraty ... | 2007 | 17475861 |
| experimental quantification of the transmission of porcine reproductive and respiratory syndrome virus. | we conducted an experiment to determine the ability of vaccine against porcine reproductive and respiratory syndrome virus (prrsv) to reduce the transmission of prrsv among pigs. at the end of the experiment, transmission rates did not differ significantly (p = 0.61) between the vaccinated and nonvaccinated pigs, the mean r-values being 0.598 (95% confidence interval [ci] 0.136 to 3.218) and 0.264 (95% ci 0.008 to 2.266), respectively. the unusually low rate of prrsv transmission in both groups ... | 2007 | 17479780 |
| porcine reproductive and respiratory syndrome virus induces apoptosis through a mitochondria-mediated pathway. | as with a number of other viruses, porcine reproductive and respiratory syndrome virus (prrsv) has been shown to induce apoptosis, although the mechanism(s) involved remain unknown. in this study we have characterized the apoptotic pathways activated by prrsv infection. prrsv-infected cells showed evidence of apoptosis including phosphatidylserine exposure, chromatin condensation, dna fragmentation, caspase activation (including caspase-8, 9, 3), and parp cleavage. dna fragmentation was dependen ... | 2007 | 17488647 |
| cd163 expression confers susceptibility to porcine reproductive and respiratory syndrome viruses. | direct functional screening of a cdna expression library derived from primary porcine alveolar macrophages (pam) revealed that cd163 is capable of conferring a porcine reproductive and respiratory syndrome virus (prrsv)-permissive phenotype when introduced into nonpermissive cells. transient-transfection experiments showed that full-length cd163 cdnas from pam, human u937 cells (histiocytic lymphoma), african green monkey kidney cells (marc-145 and vero), primary mouse peritoneal macrophages, an ... | 2007 | 17494075 |
| [enzyme-linked immunosorbent assay for detection of antibodies to porcine reproductive and respiratory syndrome virus, by using recombinant nucleocapsid protein n]. | recombinant nucleocapsid (rn) protein n of porcine reproductive and respiratory syndrome virus (prrsv) was prepared, by using the e. coli expressiom system. insertion of a polyhistidine marker into the structure of the protein allowed the latter to be purified by metal-chelate affinity chromatography. the purity of protein was confirmed by paag electrophoresis and its immunospecificity was verified by immunoblotting using rn-specific monoclonal antibodies. the protein was used as an antigen to d ... | 2007 | 17500240 |
| identification of nonessential regions of the nsp2 replicase protein of porcine reproductive and respiratory syndrome virus strain vr-2332 for replication in cell culture. | the nonstructural protein 2 (nsp2) of porcine reproductive and respiratory syndrome virus (prrsv) is a multidomain protein and has been shown to undergo remarkable genetic variation, primarily in its middle region, while exhibiting high conservation in the n-terminal putative protease domain and the c-terminal predicted transmembrane region. a reverse genetics system of prrsv north american prototype vr-2332 was developed to explore the importance of different regions of nsp2 for viral replicati ... | 2007 | 17522233 |
| porcine circovirus 2 replication in colostrum-deprived piglets following experimental infection and immune stimulation using a modified live vaccine against porcine respiratory and reproductive syndrome virus. | porcine circovirus type 2 (pcv2) infection is now recognized as the major factor in the development of post-weaning multisystemic wasting syndrome (pmws). although koch's postulates have been fulfilled for pcv2 and pmws, the severe clinical expression of the disease observed in field cases has been difficult to reproduce experimentally. some studies have demonstrated that immune stimulation associated with the use of some commercially available swine vaccines may trigger progression of pcv2 infe ... | 2007 | 17542965 |
| [construction and the immunogenicity of the recombinant modified vaccinia virus ankala co-expressing orf4, orf5 and orf6 genes of porcine reproductive and respiratory syndrome virus nj-a strain]. | to develop investigate the recombinant mva(rmva) vaccines against prrsv infection, the orf4, orf5 and orf6 of prrsv nj-a strain were subcloned into the mva transfer vector p ii lr and the resultant recombinant vector was called p ii lr-orf4/orf5/orf6. the rmva was generated by transfecting mva-infected bhk-21 cells with the recombinant vector and screened by plaque purification after x-gal staining. after six rounds of purification, insertion of prrsv gp4, gp5 and m genes into the mva genome was ... | 2007 | 17552247 |
| expression and stability of foreign tags inserted into nsp2 of porcine reproductive and respiratory syndrome virus (prrsv). | the nonstructural protein 2 (nsp2) of porcine reproductive and respiratory syndrome virus (prrsv) is the single largest protein produced during infection. the cdna of the pcmv-129 infectious prrsv clone was modified for accepting foreign tags by first creating unique mlu i and sgra i restrictions sites at nucleotide (nt) positions 3219 and 3614, respectively, within the c-terminal region of nsp2. cdnas encoding oligo- and polypeptide tags, including flag, enhanced green fluorescent protein (egfp ... | 2007 | 17553585 |
| simultaneous detection of three porcine viruses by multiplex pcr. | specific oligonucleotide primers were selected and combined in a multiplex arrangement, in order to detect simultaneously three economically important porcine viruses by polymerase chain reaction (pcr). the pathogen panel was comprised of viruses that cause reproductive failure in infected herds: aujeszky's disease virus (adv), porcine parvovirus (ppv) and porcine respiratory and reproductive syndrome virus (prrsv). in order to reduce the time required for the detection of the pathogens, the ass ... | 2007 | 17555292 |
| antiviral activity of carbohydrate-binding agents against nidovirales in cell culture. | coronaviruses are important human and animal pathogens, the relevance of which increased due to the emergence of new human coronaviruses like sars-cov, hku1 and nl63. together with toroviruses, arteriviruses, and roniviruses the coronaviruses belong to the order nidovirales. so far antivirals are hardly available to combat infections with viruses of this order. therefore, various antiviral strategies to counter nidoviral infections are under evaluation. lectins, which bind to n-linked oligosacch ... | 2007 | 17560666 |
| similarity of european porcine reproductive and respiratory syndrome virus strains to vaccine strain is not necessarily predictive of the degree of protective immunity conferred. | the objective of this study was to determine the degree of protection conferred by a lelystad-like modified live virus (mlv) vaccine against a heterologous wild-type porcine reproductive and respiratory syndrome virus (prrsv) isolate of the same cluster. for this purpose, fourteen 3-week-old piglets were divided into three groups: group a pigs were vaccinated with a modified live virus vaccine, group b pigs were used as positive controls, and group c pigs as negative controls. twenty-eight days ... | 2008 | 17560818 |
| emergence of fatal prrsv variants: unparalleled outbreaks of atypical prrs in china and molecular dissection of the unique hallmark. | porcine reproductive and respiratory syndrome (prrs) is a severe viral disease in pigs, causing great economic losses worldwide each year. the causative agent of the disease, prrs virus (prrsv), is a member of the family arteriviridae. here we report our investigation of the unparalleled large-scale outbreaks of an originally unknown, but so-called "high fever" disease in china in 2006 with the essence of prrs, which spread to more than 10 provinces (autonomous cities or regions) and affected ov ... | 2007 | 17565379 |
| porcine arterivirus attachment to the macrophage-specific receptor sialoadhesin is dependent on the sialic acid-binding activity of the n-terminal immunoglobulin domain of sialoadhesin. | the sialic acid-binding lectin sialoadhesin (sn) is a macrophage-restricted receptor for porcine reproductive and respiratory syndrome virus (prrsv). to investigate the importance of psn sialic acid-binding activity for prrsv infection, an r(116)-to-e mutation was introduced in the predicted sialic acid-binding domain of psn, resulting in a mutant, psn(re), that could not bind sialic acids. psn, but not psn(re), allowed prrsv binding and internalization. these data show that the sialic acid-bind ... | 2007 | 17567703 |
| role of cd151, a tetraspanin, in porcine reproductive and respiratory syndrome virus infection. | porcine reproductive and respiratory syndrome virus (prrsv) is a rna virus causing respiratory and reproductive diseases in swine. the susceptibility for prrsv varies between the different breeds of swine. in cell culture, prrsv virus can be propagated in primary porcine alveolar macrophages and some african green monkey kidney cell lines, such as marc-145 cells. previous studies have shown that 3' untranslated region (utr) rnas of the arteriviruses play an important role in the replication of t ... | 2007 | 17572908 |
| evaluation of the survival of porcine reproductive and respiratory syndrome virus in non-processed pig meat. | | 2007 | 17602107 |
| the challenge of prrs immunology. | porcine reproductive and respiratory syndrome (prrs) is one of the most challenging subjects of research in veterinary viral immunology, and the immune response against prrs virus (prrsv) still is poorly understood. infected pigs develop a strong and rapid humoral response but these initial antibodies do not confer protection and can even be harmful by mediating an antibody-dependent enhancement of disease. in contrast, development of neutralising antibodies (nas) is delayed and generation of ce ... | 2008 | 17644436 |
| performance of fattening pigs in a farm infected with both porcine reproductive and respiratory syndrome (prrs) virus and porcine circovirus type 2 following sow and piglet vaccination with an attenuated prrs vaccine. | the purpose of the study was to investigate whether, on farms with both post-weaning multisystemic wasting syndrome (pmws) and porcine reproductive and respiratory syndrome (prrs), the prrs vaccination of sows and their fattening pigs protects against these syndromes. in a farrow-to-finish pig farm with a history of prrs and pmws, 200 gilts and sows were allocated to one of two groups of equal size. the first group (c-sow group) was used as untreated controls, while the animals of the second gro ... | 2007 | 17650147 |
| porcine beta-defensin 2 displays broad antimicrobial activity against pathogenic intestinal bacteria. | defensins are small antimicrobial peptides that play an important role in the innate immune system of mammals. here, we describe the antimicrobial activity of pbd-2, a recently discovered new porcine defensin that is produced in the intestine. a synthetic peptide corresponding to the mature protein showed high antimicrobial activity against a broad range of pathogenic bacteria, while it only showed limited hemolytic activity against porcine red blood cells. highest activity was observed against ... | 2008 | 17658606 |
| applying spatial analysis to a porcine reproductive and respiratory syndrome regional control programme. | | 2007 | 17660468 |
| molecular cloning, expression, purification and crystallographic analysis of prrsv 3cl protease. | 3cl protease, a viral chymotrypsin-like proteolytic enzyme, plays a pivotal role in the transcription and replication machinery of many rna viruses, including porcine reproductive and respiratory syndrome virus (prrsv). in this study, the full-length 3cl protease from prrsv was cloned and overexpressed in escherichia coli. crystallization experiments yielded crystals that diffracted to 2.1 a resolution and belong to space group c2, with unit-cell parameters a = 112.31, b = 48.34, c = 42.88 a, be ... | 2007 | 17671377 |
| analysis of immunogenicity of minor envelope protein gp3 of porcine reproductive and respiratory syndrome virus in mice. | porcine reproductive and respiratory syndrome virus (prrsv) is one of the most economically significant viral diseases in swine industry. though the minor envelope protein gp3 is associated with protective immunity, its immunogenicity and protective mechanism are poorly known. in this study, two recombinant adenoviruses, rad-gp3 expressing complete gp3 and rad-tgp3 expressing truncated gp3 in which aa2-64 were deleted, were constructed and the immunogenicity were tested in a mouse model. four gr ... | 2007 | 17671834 |
| suppression of porcine reproductive and respiratory syndrome virus replication in marc-145 cells by shrna targeting orf1 region. | porcine reproductive and respiratory syndrome (prrs) is an economically important disease in swine producing area. the current vaccine strategies cannot provide complete protection against prrsv. the objective of this study was to determine if specific short-hairpin rna (shrna) directed against different genomic regions of orf1b of prrsv could be utilized to inhibit virus replication in marc-145 cells. two shrna expression vectors targeting orf1b gene of prrsv were constructed and delivered into ... | 2007 | 17671836 |
| influence of porcine reproductive and respiratory syndrome virus gp5 glycoprotein n-linked glycans on immune responses in mice. | porcine reproductive and respiratory syndrome virus (prrsv) is one of the most economically significant viral diseases in the swine industry. infection with prrsv following vaccination is common, since protection is incomplete. persistent infection may be one of the biggest obstacles to control of the disease. "glycan shielding" was postulated to be a primary mechanism to explain evasion from neutralizing immune response, ensuring in vivo persistence of virus, such as hiv, siv, and hbv. the obje ... | 2007 | 17671839 |
| [recovery of an infectious virus from the full-length cdna of prrsv bj-4]. | six recombinant plasmids covering cdna of porcine reproductive and respiratory syndrome virus bj-4 were sequenced, respectively, and 23 point mutations were reverted with site-directed mutagenesis kit. the full-length cdna clone pwsk-dcba was assembled and re-sequenced. the capped viral genomic rna was transcribed in vitro, mixed with liposome and transfected into marc-145 cells, and an infectious virus (designated rv68) was rescued. the rescued virus was able to induce cpe typical of prrsv on m ... | 2007 | 17672299 |
| virology. china, vietnam grapple with 'rapidly evolving' pig virus. | | 2007 | 17717158 |
| evaluation of surveillance protocols for detecting porcine reproductive and respiratory syndrome virus infection in boar studs by simulation modeling. | because porcine reproductive and respiratory syndrome virus (prrsv) can be transmitted through semen, prrsv-free boar studs need to be routinely monitored to rapidly detect any potential prrsv introduction. however, current protocols for monitoring prrsv in boar studs are diverse, sometimes very costly, and their effectiveness has not been quantified. the objective of this study was to evaluate the ability of different monitoring protocols to detect prrsv introduction into a negative boar stud b ... | 2007 | 17823392 |
| evaluation of the sensitivity of reverse-transcription polymerase chain reaction to detect porcine reproductive and respiratory syndrome virus on individual and pooled samples from boars. | boar studs are continuously monitored for the presence of porcine reproductive and respiratory syndrome virus (prrsv) by testing different biological samples by reverse-transcription polymerase chain reaction (rt-pcr). in most cases, samples are run in pools, even though the impact of pooling on the sensitivity of rt-pcr is unknown. the objective of this study was to evaluate the feasibility of using pcr on pooled samples through the estimation of the sensitivity of rt-pcr on different biologica ... | 2007 | 17823393 |
| the emergence of porcine circovirus 2b genotype (pcv-2b) in swine in canada. | since late 2004, the swine industry in the province of quebec has experienced a significant increase in death rate related to postweaning multisystemic wasting syndrome (pmws). to explain this phenomenon, 2 hypotheses were formulated: 1) the presence of a 2nd pathogen could be exacerbating the porcine circovirus 2 (pcv-2) infection, or 2) a new and more virulent pcv-2 strain could be infecting swine. in 2005, 13 pmws cases were submitted to the quebec provincial diagnostic laboratory and pcv-2 w ... | 2007 | 17824323 |
| porcine plasma ficolin binds and reduces infectivity of porcine reproductive and respiratory syndrome virus (prrsv) in vitro. | ficolins are collagenous lectins that bind n-acetylated glycans and participate in innate immune responses, including phagocytosis and complement activation. related collagenous lectins such as mannan binding lectin (mbl) and surfactant proteins a and d possess antiviral activity, but this activity has not been demonstrated for ficolins. in these studies, we used purified porcine plasma ficolin alpha and recombinant ficolin alpha to assess their ability to bind and neutralize porcine reproductiv ... | 2008 | 17850894 |
| genetic diversity of porcine reproductive and respiratory syndrome virus strains circulating in hungarian swine herds. | analysis of 37 orf5 sequences of hungarian porcine reproductive and respiratory syndrome virus (prrsv) strains revealed that most of them (35) belonged to the european genotype, forming distinct subgroups, reflecting the exceptional diversity of eastern european strains. twelve vaccine-like strains were also found in non-vaccinated animals. two strains belonged to the american genotype showing 90-91% nucleotide identity to the "quebec" canadian reference strain. the analysis of the putative ecto ... | 2008 | 17869032 |
| emergence of a highly pathogenic porcine reproductive and respiratory syndrome virus in the mid-eastern region of china. | herds of pigs in the mid-eastern region of china have experienced recent outbreaks of a severe form of porcine reproductive and respiratory syndrome (prrs) characterised by high fever and morbidity and mortality in animals of different ages. eighty-one herds were diagnosed with prrs virus (prrsv) infection from june to december 2006 on the basis of clinical signs, pathological findings and reverse transcriptase polymerase chain reaction (rt-pcr). twenty strains of prrsv were isolated from 20 her ... | 2007 | 17869553 |
| [studies on porcine reproductive and respiratory syndrome virus morphogenesis in marc-145 cell and the ultrastructural changes of the infected cells]. | electron microscopy was employed for ultrastructural observation of marc-145 cells infected with porcine reproductive and respiratory syndrome virus (prrsv) sc1 strain and studied the virus morphogenesis in infected cells. the results demonstrated that prrsv was spherical and enveloped. the virion is 45-65 nm in diameter and its nucleocapsid was approximately 25-30 nm. prrsv entered marc-145 cells by endocytosis, and replicated in the cytoplasm. the mature viruses were released from infected cel ... | 2007 | 17886720 |
| [the genome of porcine reproductive and respiratory syndrome virus and the molecular basis of pathogenesis]. | | 2007 | 17886728 |
| ifn-alpha treatment enhances porcine arterivirus infection of monocytes via upregulation of the porcine arterivirus receptor sialoadhesin. | the arterivirus porcine reproductive and respiratory syndrome virus (prrsv) has a specific tropism for a subset of differentiated macrophages. porcine sialoadhesin was identified as a prrsv internalization receptor that is, similarly to sialoadhesins from other species, only expressed on subsets of macrophages. sialoadhesin is not expressed or only expressed at low levels on monocytes, which might explain why monocytes are largely refractory to prrsv infection. different molecules have been iden ... | 2007 | 17892397 |
| the stealthy nature of prrsv infection: the dangers posed by that ever-changing mystery swine disease. | | 2007 | 17897848 |
| risk factors for salmonella seroconversion of fattening pigs in farrow-to-finish herds. | we did a prospective observational 9-month long study to quantify risk factors of managerial and hygiene practices, and pig-health status for salmonella seroconversion of fattening pigs reared in subclinically infected french farrow-to-finish farms. during the fattening phase, 2,649 pigs belonging to the same batch of contemporary pigs, from 89 conventional farrow-to-finish farms were individually followed and regularly blood sampled on a monthly basis. farm recruitment was based on the farmer's ... | 2007 | 17903417 |
| purification of the major envelop protein gp5 of porcine reproductive and respiratory syndrome virus (prrsv) from native virions. | porcine reproductive and respiratory syndrome virus (prrsv) is the cause of an economically important swine disease that has been devastating the global swine industry since the early 1990s. the current prrsv vaccines are not very effective largely due to heterogeneic nature of the virus. the major envelope protein, gp5, exposes outside the virion, induces neutralizing antibodies, and thus is a primary target for developing a subunit vaccine. in this study, we report a process for purification o ... | 2008 | 17913250 |
| co-expressing gp5 and m proteins under different promoters in recombinant modified vaccinia virus ankara (rmva)-based vaccine vector enhanced the humoral and cellular immune responses of porcine reproductive and respiratory syndrome virus (prrsv). | the porcine reproductive and respiratory syndrome virus (prrsv) has three major structural proteins which designated as gp5, m, and n. protein gp5 and m have been considered very important to arouse the humoral and cellular immune responses against prrsv infection and proposed to be the excellent candidate proteins in the design of prrs bioengineering vaccine. there were some attempts on expressing gp5 or m in dna vaccine and adenovirus to arouse humoral and cellular immune responses, but few pa ... | 2007 | 17922181 |
| [transmission of agents of the porcine respiratory disease complex (prdc) between swine herds: a review. part 1--diagnosis, transmission by animal contact]. | knowledge on the different ways of transmitting prdc pathogens (prrsv, influenza virus a, pcv 2, m. hyopneumoniae, a. pleuropneumoniae) between swine herds is of special interest for the development of biosecurity measures or the retrospective risk analysis in the framework of activities of the consulting veterinarian. in this literature review the current knowledge of the transmission of prdc-pathogens is summarized. since the assessment of investigations into pathogen detection in detail is in ... | 2007 | 17927073 |
| use of an experimental model to test the efficacy of planned exposure to live porcine reproductive and respiratory syndrome virus. | the objectives of this study were to test the efficacy and safety of planned exposure to porcine reproductive and respiratory syndrome virus (prrsv) in protecting naïve and previously exposed pigs against prrsv challenge and to gain information on the dose of prrsv necessary to induce a protective immune response. fifty 2-week-old pigs were randomly assigned to one of five groups: a group exposed to a low dose of autogenous prrsv vaccine (the l-vac group), a group exposed to a high dose of autog ... | 2007 | 17928430 |
| genetic perspectives on host responses to porcine reproductive and respiratory syndrome (prrs). | porcine reproductive and respiratory syndrome (prrs) is the most economically important disease in pig populations, worldwide. current research, both in vitro and in vivo, has failed to provide industry with a reliable or effective method to combat the disease. in this paper the present knowledge of the genetics of the host response to porcine reproductive and respiratory syndrome virus (prrsv) is reviewed. special reference is made to clinical signs of disease, in vitro and in vivo studies, and ... | 2007 | 17931105 |
| infection dynamics of porcine reproductive and respiratory syndrome virus in a continuous-flow population of pigs also infected with mycoplasma hyopneumoniae. | twenty-eight 10-week-old pigs were inoculated intratracheally with 1 x 10(5) colour-changing units/ml mycoplasma hyopneumoniae strain 232, and another 32 pigs were not inoculated but were divided into 12 direct-contact pigs and 20 indirect-contact pigs. thirty-five days later, the inoculated pigs were inoculated intranasally with 1 x 10(2.4) tcid50 of porcine reproductive and respiratory syndrome virus (prrsv) strain mn 30-100. viraemia, seroconversion and the transmission of prrsv in the m hyop ... | 2007 | 17938409 |
| antigen-specific b-cell responses to porcine reproductive and respiratory syndrome virus infection. | porcine reproductive and respiratory syndrome virus (prrsv) causes an acute, viremic infection of 4 to 6 weeks, followed by a persistent infection lasting for several months. we characterized antibody and b-cell responses to viral proteins in acute and persistent infection to better understand the immunological basis of the prolonged infection. the humoral immune response to prrsv was robust overall and varied among individual viral proteins, with the important exception of a delayed and relativ ... | 2008 | 17942527 |
| rapid detection and strain identification of porcine reproductive and respiratory syndrome virus (prrsv) by real-time rt-pcr. | to develop and validate assays based on real-time reverse transcriptase-polymerase chain reaction (rt-pcr) for rapid detection and strain identification (european and north american strains) of porcine reproductive and respiratory syndrome virus (prrsv) by using sybr green i and taqman probe chemistries. | 2008 | 17944835 |
| studies on the aetiology of non-suppurative encephalitis in pigs. | thirty-eight natural cases of aetiologically unclear non-suppurative encephalitis in pigs were studied retrospectively. brain samples were examined for the presence of porcine circovirus type 2 (pcv-2), porcine respiratory and reproductive syndrome virus (prrsv), porcine enteroviruses (pevs), ovine herpesvirus type 2 (ovhv-2), borna disease virus (bdv) and suid herpesvirus type 1 (suhv-1) by molecular biological and immunohistochemical methods. histological examination of the brains revealed var ... | 2007 | 17951563 |
| peptide-conjugated morpholino oligomers inhibit porcine reproductive and respiratory syndrome virus replication. | porcine reproductive and respiratory syndrome (prrs) has been devastating the global swine industry for more than a decade, and current strategies to control prrs are inadequate. in this study we characterized the inhibition of prrs virus (prrsv) replication by antisense phosphorodiamidate morpholino oligomers (pmo). of 12 peptide-conjugated pmo (ppmo), four were found to be highly effective at inhibiting prrsv replication in cell culture in a dose-dependant and sequence-specific manner. ppmo 5u ... | 2008 | 17959259 |
| [transmission of agents of the porcine respiratory disease complex (prdc) between swine herds: a review. part 2--pathogen transmission via semen, air and living/nonliving vectors]. | the transmission of prdc-pathogens (prrsv, influenza virus a, pcv2, m. hyopneumoniae, a. pleuropneumoniae) between swine herds, which was summarized in the first part of the review, mainly occurs via pig movement. the risk of pathogen transmission by insemination with contaminated semen plays only a relevant role in the infection with prrsv and pcv2. a risk of the aerogen transmission of pathogens between herds within a distance of 2 to 3 km is described for m. hyopneumoniae and prrsv. evidence ... | 2007 | 17970334 |
| development of a novel hot-start multiplex pcr for simultaneous detection of classical swine fever virus, african swine fever virus, porcine circovirus type 2, porcine reproductive and respiratory syndrome virus and porcine parvovirus. | a novel hot-start multiplex pcr (mpcr) assay was developed and subsequently evaluated for its effectiveness in simultaneously detecting multiple viral infections of swine. specific primers for each of five virus genomes, namely classical swine fever virus (csfv), african swine fever virus (asfv), porcine circovirus type 2 (pcv2), porcine reproductive and respiratory syndrome virus (prrsv) and porcine parvovirus (ppv) were used. combined nucleic acid purification was carried out using a commercia ... | 2008 | 17975735 |
| attenuation of porcine reproductive and respiratory syndrome virus strain mn184 using chimeric construction with vaccine sequence. | two genetically distinct infectious recombinant virus clones (pmlv, constructed from ingelvac prrs mlv and pmn184, constructed from virulent strain mn184) were developed to study attenuation of contemporary porcine reproductive and respiratory syndrome virus (prrsv) strain mn184. two reciprocal chimeric clones (pmlvorf1/mn184 and pmn184orf1/mlv) were then constructed, such that the 5'utr/orf1 of one genotype was linked to orf2-7/3'utr from the other genotype. in vitro studies demonstrated that t ... | 2008 | 17976680 |
| construction and immunogenicity of pseudotype baculovirus expressing gp5 and m protein of porcine reproductive and respiratory syndrome virus. | baculovirus, which is extensively utilized as an excellent tool for production of recombinant protein in insect cells, has recently emerged as a novel and attractive gene delivery vehicle for mammalian cells. in the present study, a pseudotype baculovirus (with the glycoprotein of vesicular stomatitis virus (vsv-g) on the envelope) was used as vector to construct recombinant baculovirus coexpressing gp5 and m protein of porcine reproductive and respiratory syndrome virus (prrsv), under the trans ... | 2007 | 17980465 |
| intranasal administration of cpg oligonucleotides induces mucosal and systemic type 1 immune responses and adjuvant activity to porcine reproductive and respiratory syndrome killed virus vaccine in piglets in vivo. | oligonucleotides containing cpg motifs (cpg odn) are strong adjuvants for immune responses, particularly in mice. recently, it has been showed that cpg odn is a promising mucosal adjuvant in mice, but data on mucosal immune responses induced by cpg odn in piglets are scarce. we have previously demonstrated that cpg odn is a potent adjuvant to pseudorabies attenuated virus (prv) vaccine when administered subcutaneously (sc) in newborn piglets. herein, we evaluated intranasal (in) delivery of cpg ... | 2007 | 17996683 |
| the relationship between infectious and non-infectious herd factors with pneumonia at slaughter and productive parameters in fattening pigs. | this paper explores the relationship between infectious and non-infectious herd factors with the occurrence of pneumonia at slaughter and productive parameters in fattening pigs on 39 fattening herds. a questionnaire was used to obtain environmental and management factors (non-infectious factors). blood samples and lungs were obtained from 35 pigs in each herd at slaughter. serological testing was performed for antibodies against three respiratory pathogens (infectious factors): porcine reproduc ... | 2009 | 18023215 |
| [selection and inhibitory effect analysis of sirnas specific to orf2-4 of porcine reproductive and respiratory syndrome virus]. | rna interference (rnai) is a powerful tool in gene function research. in order to investigate the role of gp2, gp3 and gp4 of porcine reproductive and respiratory syndrome virus (prrsv) in the viral replication, small interference rnas (sirnas) directed to orf2, orf3 and orf4 were designed and 12 short hairpin rna (shrna) expression vectors were constructed (designed as 21,22,23,24,31,32,33,34,41,42,43 and 44). cells treated with shrna expression vectors were infected by prrsv. the effective shr ... | 2007 | 18051854 |
| simultaneous detection and genotyping of porcine reproductive and respiratory syndrome virus (prrsv) by real-time rt-pcr and amplicon melting curve analysis using sybr green. | the feasibility of using a sybr green-based real-time rt-pcr assay (sybr green reti rt-pcr) followed by melting curve analysis (mca) for detecting and genotyping porcine reproductive and respiratory syndrome virus (prrsv) was assessed. the sybr green reti rt-pcr and a previously reported two-step, non-nested rt-pcr assays were simultaneously tested on selected european (eu) and north american (us) prrsv strains and isolates collected from diverse clinical, temporal, and geographical origins. the ... | 2008 | 18054369 |
| analysis of the risk of introduction and spread of porcine reproductive and respiratory syndrome virus through importation of raw pigmeat into new zealand. | to determine the frequency with which porcine reproductive and respiratory syndrome (prrs) virus (prrsv) would become established in a non-commercial pig herd in new zealand due to illegal feeding of uncooked food waste containing virus-contaminated pigmeat. to determine the likelihood of a single incursion resulting in a multi-farm outbreak of the disease, and describe the spatio-temporal characteristics of such an outbreak. | 2007 | 18059652 |
| descriptive summary of an outbreak of porcine post-weaning multisystemic wasting syndrome (pmws ) in new zealand. | investigations were conducted to determine the cause of an acute, multi-farm outbreak of porcine respiratory disease that included diarrhoea and subsequent loss of body condition in affected pigs. a definition for post-weaning multisystemic wasting syndrome (pmws) including both clinical and pathological features, previously developed for the pig industry in new zealand, was applied to the current outbreak. in addition to self-reporting by owners of affected farms, local veterinarians, disease a ... | 2007 | 18059655 |
| [identification of porcine reproductive and respiratory syndrome virus regulation sequence in 3'-untranslated region]. | based on our established infectious clone of prrsv, designated as pcbc2, a series of mutagenesis of 3'-untranslated region (3'-utr) at primary structure and secondary structure level were constructed. then the full length mutant clones were transfected into marc-145 cells, from which the influences of the discrete 3'-utr mutation on prrsv replication and transcription were analyzed. the properties of the rescued mutant viruses were then further characterized by northern blot and plaque morpholog ... | 2007 | 18062247 |
| failure of an inactivated vaccine against porcine reproductive and respiratory syndrome to protect gilts against a heterologous challenge with prrsv. | this study was designed to evaluate the efficacy of an inactivated vaccine based on a european-type strain of porcine reproductive and respiratory syndrome virus (prrsv) against the reproductive form of the syndrome in breeding gilts, and any congenital disease in their piglets. five gilts were vaccinated twice, following the manufacturer's instructions, before they were inseminated. nine additional gilts remained unvaccinated and served as positive (five gilts) and negative (four gilts) control ... | 2007 | 18083979 |
| [prrsv-eradication: an option for pig herds in germany?]. | the problem of successfully controling prrs with traditional methods has led to a growing interest in eradication. this review summarizes the current literature on topics of prrs-eradication, including the relevant routine diagnostic procedures, routes of virus transmission between pig herds (as i.e. pig movement, semen, aerosols, insects, fomites, transport vehicles) and eradication by close&rollover and test&removal, respectively. on the basis of this knowledge and experiences it can be conclu ... | 2007 | 18085157 |
| changes in peripheral blood leukocyte subpopulations in piglets co-infected experimentally with porcine reproductive and respiratory syndrome virus and porcine circovirus type 2. | porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus type 2 (pcv2) are pathogens, which can significantly affect the swine industry worldwide. field surveys suggest that simultaneous prrsv and pcv2 infection is common in pigs. the objective of this study was to measure the changes in peripheral blood leukocyte subpopulations in piglets co-infected experimentally with prrsv and pcv2, in order to analyze the synergistic influence of co-infection on the immune system. ... | 2008 | 18164875 |
| effect of the serum albumin on replication of porcine reproductive and respiratory syndrome virus in a cell culture. | | 2007 | 18197738 |
| the nsp1alpha and nsp1 papain-like autoproteinases are essential for porcine reproductive and respiratory syndrome virus rna synthesis. | the two n-terminal cleavage products, nsp1alpha and nsp1beta, of the replicase polyproteins of porcine reproductive and respiratory syndrome virus (prrsv) each contain a papain-like autoproteinase domain, which have been named pcpalpha and pcpbeta, respectively. to assess their role in the prrsv life cycle, substitutions and deletions of the presumed catalytic cysteine and histidine residues of pcpalpha and pcpbeta were introduced into a prrsv infectious cdna clone. mutations that inactivated pc ... | 2008 | 18198380 |
| phenotypic and functional modulation of bone marrow-derived dendritic cells by porcine reproductive and respiratory syndrome virus. | it is well documented that there is a delay in the development of effective immunity to porcine reproductive and respiratory syndrome virus (prrsv) in infected and vaccinated pigs. this suggests that prrsv might possess some inherent properties to evade host defense mechanisms during the early stage of infection. dendritic cells (dcs) play a crucial role in the activation and control of t-cells in response to viral antigens. in this study, we investigated the phenotypic and functional property c ... | 2008 | 18221843 |
| genetic characterization of the korean porcine reproductive and respiratory syndrome viruses based on the nucleocapsid protein gene (orf7) sequences. | to investigate the genetic characteristics of the korean porcine reproductive and respiratory syndrome virus (prrsv), we determined the complete sequence of the nucleocapsid protein gene (orf7) from 105 prrsv isolates from all nine korean prefectures during the years 2003 through 2006. these sequences were then analyzed along with the published orf7 sequences for two korean prrs viruses (pl97-1/1997 and lmy/2002) and 36 non-korean viruses. the orf7 nucleotide sequence identities among the 107 ko ... | 2008 | 18227969 |
| feasibility of pooled-sample testing for the detection of porcine reproductive and respiratory syndrome virus antibodies on serum samples by elisa. | surveillance of porcine reproductive and respiratory syndrome (prrs) in negative sow farms is usually performed by testing for the presence of antibodies against prrs virus in serum with a commercial elisa test. the objective of this study was to evaluate the feasibility of pooling serum samples for detection of prrs virus antibodies by elisa. the effect of pool size on the sensitivity and specificity of the elisa test was evaluated by testing true positive samples and false positive samples, re ... | 2008 | 18243590 |
| construction of infectious cdna clones of prrsv: separation of coding regions for nonstructural and structural proteins. | porcine reproductive and respiratory syndrome virus (prrsv), the causative agent of the ongoing "porcine high fever syndrome" in china, is capable of genetic and antigenic mutations at high frequency. how to design vaccine rationally to keep up with the ever-changing prevalent prrsv variant is of great interest. we developed an infectious cdna clone of an attenuated strain of type ii prrsv, and further manipulated the infectious cdna clone by inserting polylinker between orf1 and orf2, encoding ... | 2008 | 18246315 |
| porcine reproductive and respiratory syndrome virus subverts repertoire development by proliferation of germline-encoded b cells of all isotypes bearing hydrophobic heavy chain cdr3. | isolator piglets infected with porcine reproductive and respiratory syndrome virus (prrsv), which is related to the lactate dehydrogenase-elevating virus of mice, develop severe hypergammaglobulinemia, lymph node adenopathy, and autoimmune disease. many of the polyclonally activated b cell clones bear hydrophobic h chain cdr3s (hcdr3s) and are disseminated to most lymphoid tissues. we show in this study that b cells with identical hydrophobic hcdr3s are expressed with all major isotypes in prrsv ... | 2008 | 18250444 |
| highly pathogenic porcine reproductive and respiratory syndrome, china. | | 2007 | 18252136 |
| a recombinant plasmid co-expressing swine ubiquitin and the gp5 encoding-gene of porcine reproductive and respiratory syndrome virus induces protective immunity in piglets. | we transfected a recombinant plasmid that co-expressed swine ubiquitin and a codon optimized gp5 encoding-gene of porcine reproductive and respiratory syndrome virus (prrsv), designated pca-u-optigp5, as well as the plasmid pca-optigp5 encoding codon optimized gp5, and the plasmid pca-gp5 expressing wild-type pgp5 into 293t cells. expression of gp5 was measured by indirect immunofluorescence (iif) assay and western blot and found to be considerably higher in response to pca-u-optigp5 than the wi ... | 2008 | 18262692 |
| porcine reproductive and respiratory syndrome virus infects mature porcine dendritic cells and up-regulates interleukin-10 production. | porcine reproductive and respiratory syndrome virus (prrsv) infects mature dendritic cells (mdcs) derived from porcine monocytes and matured with lipopolysaccharide. the infection of mdcs induced apoptosis, reduced the expression of cd80/86 and major histocompatibility complex class ii molecules, and increased the expression of interleukin-10, thus suggesting that such mdc modulation results in the impairment of t-cell activation. | 2008 | 18272667 |
| different biological characteristics of wild-type porcine reproductive and respiratory syndrome viruses and vaccine viruses and identification of the corresponding genetic determinants. | two attenuated vaccines, ingelvac prrs mlv and ingelvac prrs atp, derived from vr2332 and ja142, respectively, have been used to control porcine reproductive and respiratory syndrome (prrs) virus. however, there have been several field reports concerning the reversion of the vaccine virus to virulence. furthermore, viruses genetically indistinguishable from the vaccines and wild-type parental viruses have been detected in clinical prrs cases, raising the need for a better differential tool. as t ... | 2008 | 18272711 |
| associations between pathogens in healthy pigs and pigs with pneumonia. | the aim of this study was to evaluate the associations between different pathogens in the development of pneumonia and bronchopneumonia in pigs. samples of bronchoalveolar lavage fluid from 100 pigs showing no clinical signs and 239 pigs with clinical signs of respiratory disease were examined for mycoplasma hyopneumoniae, mycoplasma hyorhinis, us-type porcine respiratory and reproductive syndrome virus (prrsv), eu-type prrsv, porcine circovirus type 2 (pcv-2), influenza virus type a, alpha-haem ... | 2008 | 18310558 |
| rapid detection of a highly virulent chinese-type isolate of porcine reproductive and respiratory syndrome virus by real-time reverse transcriptase pcr. | an outbreak of highly virulent chinese-type of porcine reproductive and respiratory syndrome virus (h-prrsv) in most areas of china recently has led to huge economic losses and drawn great attention to its diagnosis and disease control. to facilitate rapid identification of h-prrsv, a fluorogenic-probe hydrolysis (taqman)-reverse transcriptase pcr for h-prrsv has been developed. primers and probe specificity were evaluated with rna extracted from 5 strains of h-prrsv and 24 strains of other viru ... | 2008 | 18313768 |
| detection of porcine reproductive and respiratory syndrome virus infection in porcine oral fluid samples: a longitudinal study under experimental conditions. | isolation of porcine reproductive and respiratory syndrome virus (prrsv) from oral fluids was first reported in 1997. the objective of the present study was to determine whether prrsv and/or anti-prrsv antibodies were present in oral fluids at diagnostic levels. the level and duration of prrsv and anti-prrsv antibodies in serum and oral fluids was evaluated in 3 age groups of pigs (4, 8, or 12 weeks of age) inoculated with a type 2 (north american) prrsv isolate. serum, buccal swabs, and pen-bas ... | 2008 | 18319427 |
| re: analysis of the risk of introduction and spread of porcine reproductive and respiratory syndrome virus through importation of raw pigmeat into new zealand. | | 2008 | 18322560 |
| porcine reproductive and respiratory syndrome virus (prrsv) suppresses interferon-beta production by interfering with the rig-i signaling pathway. | porcine reproductive and respiratory syndrome virus (prrsv) is the cause of an economically important swine disease that has been devastating the swine industry since the late 1980s. accumulating evidences have revealed that prrsv infection fails to induce type i interferon (ifn-alpha/beta), which are normally induced rapidly during virus replication in virus-infected cells. however, the potential mechanisms remain largely unclear. in this study, we showed that prrsv infection activated the sign ... | 2008 | 18336912 |
| generation of internal image monoclonal anti-idiotypic antibodies against idiotypic antibodies to gp5 antigen of porcine reproductive and respiratory syndrome virus. | syngeneic monoclonal anti-idiotypic antibodies (mab2s) were generated against idiotypic antibodies to membrane glycoprotein gp5 of porcine reproductive and respiratory syndrome virus (prrsv) using the sequential immunization method. six of 12 mab2s possessed potential internal image characteristics by recognizing a common idiotype on murine and swine anti-gp5 antibodies. further serological characterization demonstrated that one of the mab2 (mab2-5g2) represents internal image anti-idiotope whic ... | 2008 | 18336924 |
| elimination of porcine reproductive and respiratory syndrome virus from a seedstock breeding farm and a supplying boar stud by a modified test and removal method. | to eliminate porcine reproductive and respiratory syndrome virus (prrsv) from a supplying boar stud, samples of serum and semen from 118 boars were assessed three times a month by an indirect fluorescent antibody (ifa) test to detect antibodies, and by a nested reverse transcriptase-pcr (nrt-pcr) to detect the genome of prrsv. the boars detected as persistently infected carriers were culled. a prrsv-negative population of boars was established after three months and no semen positive for the vir ... | 2008 | 18344497 |
| comparative antiviral and proviral factors in semen and vaccines for preventing viral dissemination from the male reproductive tract and semen. | many animal and human viruses are disseminated via semen, but there is little information on how to measure and stimulate protective antiviral immunity in the male reproductive tract and semen. this information is important since successful vaccination through the stimulation of protective immune responses could be a mechanism to prevent viral contamination of semen and subsequent wide spread viral dissemination. even control of the infection by shortening the duration of viral shedding and lowe ... | 2008 | 18348741 |
| rapid detection of porcine circovirus type 2 by loop-mediated isothermal amplification. | a method of loop-mediated isothermal amplification (lamp) was employed to develop a rapid and simple detection system for porcine circovirus type 2 (pcv2). the amplification could be finished in 60 min under isothermal condition at 64 degrees c by employing a set of four primers targeting the cap gene of pcv2. the lamp assay showed higher sensitivity than the conventional pcr, with a detection limit of five copies per tube of purified pcv2 genomic dna. no cross-reactivity was observed from the s ... | 2008 | 18355932 |
| recovery of viable porcine reproductive and respiratory syndrome virus from an infectious clone containing a partial deletion within the nsp2-encoding region. | non-structural protein 2 (nsp2) of porcine reproductive and respiratory syndrome virus (prrsv) is the most variable region and postulated to play an important role in cell and tissue tropism of prrsv. to investigate the role of nsp2 in the viability and growth of prrsv in cells in vitro, two cdna clones were constructed containing a deletion of 63 consecutive nucleotides (pwsk-dcbad63) or 117 nucleotides (pwsk-dcbad117) within the nsp2-encoding region of prrsv (bj-4). the clone pwsk-dcbad63 was ... | 2008 | 18357408 |
| evaluation of the pathogenicity and transmissibility of a chilean isolate of porcine reproductive and respiratory syndrome virus. | the objective of this study was to determine clinical features, shedding and transmission of a chilean porcine reproductive and respiratory syndrome virus (prrsv) strain upon experimental inoculation of 4-week-old pigs. six groups of five animals each were used. the g1 (donor) group was inoculated with prrsv, maintained in an isolation unit for 35 days, and sampled daily to determine shedding in mucosal secretions and faeces, viraemia and seroconversion. an uninfected control group (g6) was equa ... | 2008 | 18397499 |