Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
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 ...200111370681
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 + ...200111374547
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 ...200111376957
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 ...200111395197
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 ...200111402653
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 ...200111411506
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, ...200111425255
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 ...200111427564
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.200111435984
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 ...200111437498
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 ...200111437499
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) ...200111467478
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 ...200111482613
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 ...200111498245
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 ...200111504553
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 ...200111543885
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 ...200111551659
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 ...200111572560
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 ...200111574173
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 ...200111587732
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 ...200111592614
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 ...200111594382
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 ...200111601900
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 ...200111602771
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 ...200111602772
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 ...200111665881
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 ...200111689039
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 ...200111692508
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 ...200111118739
efficacy of porcine reproductive and respiratory syndrome virus vaccine and porcine interleukin-12.the efficacy of porcine recombinant interleukin-12 (pril-12) as an adjuvant to stimulate immunity was investigated in pigs vaccinated against porcine reproductive and respiratory syndrome virus (prrsv). porcine recombinant il-12 was cloned and expressed in the insect baculovirus system. thirty pigs were randomly allocated to five groups, and individual pigs were injected with prrsv modified live virus with and without coadministration of pril2; prrsv killed virus with and without coadministratio ...200119753703
construction and immunogenicity of recombinant mycobacterium bovis bcg expressing gp5 and m protein of porcine reproductive respiratory syndrome virus.mycobacterium bovis bcg was used to express a truncated form of gp5 (lacking the first 30 nh(2)-terminal residues) and m protein of porcine reproductive and respiratory syndrome virus (prrsv). the prrsv proteins were expressed in bcg under control of the mycobacterial hsp60 gene promoter either in the mycobacterial cytoplasm (bcggp5cyt and bcgmcyt) or as mt19-fusion proteins on the mycobacterial surface (bcggp5surf and bcgmsurf). mice inoculated with bcggp5surf and bcgmsurf developed antibodies ...200212443659
genetic characterization and phylogenetic analysis of porcine circovirus type 2 (pcv2) strains from cases presenting various clinical conditions.porcine circovirus type 2 (pcv2) has been associated with a newly identified and described disease in swine called the postweaning multisystemic wasting syndrome (pmws). an association of pcv2 with various other clinical conditions in pigs are also increasingly being reported. to date molecular studies to determine the extent of genetic variations of this virus have been limited. to more fully understand the extent of genetic diversity we report the sequencing of 34 pcv2 strains from eastern can ...200212457966
chimeric arteriviruses generated by swapping of the m protein ectodomain rule out a role of this domain in viral targeting.arteriviruses are enveloped, positive-strand rna viruses for which the two major envelope proteins gp(5) and m occur as disulfide-linked heterodimers. these were assumed to serve the viral targeting functions, but recent ectodomain swapping studies with equine arteritis virus (eav) indicate that the gp(5) protein does not determine arteriviral tropism. here, we focused on the short, 13- to 18-residue ectodomain of the m protein. using an infectious cdna clone of the lelystad virus isolate of por ...200212490397
the primary neutralization epitope of porcine respiratory and reproductive syndrome virus strain vr-2332 is located in the middle of the gp5 ectodomain.pigs infected with porcine respiratory and reproductive syndrome virus (prrsv) strain vr-2332 were found to generate high levels of antibodies (abs) that bound in an indirect elisa to synthetic peptides representing segments of the primary envelope glycoprotein (gp5) ectodomain of this virus. use of overlapping gp5 ectodomain peptides of various length indicated that the epitope recognized by the abs was located in the middle of the ectodomain (amino acids 36-52), in the same relative segment th ...200212491101
leader-body junction sequence of the viral subgenomic mrnas of porcine reproductive and respiratory syndrome virus isolated in taiwan.in combination of utilizing a leader specific primer and primers complementary to porcine reproductive and respiratory syndrome virus (prrsv) genome through rt-pcr, the leader junction sequences of subgenomic mrna (sg mrna) was identified from a taiwanese isolate of prrsv. thirty-six cdna clones derived from sg mrnas 2, 3, 4, 5, 6 and 7 were determined. the junction sequences analyzed from different sg mrna were found to contain a similar 5 nucleotide sequence motif, (u/g)(c/a)(a/g)cc. the dista ...200212499678
expression of open reading frame 5 protein of porcine reproductive and respiratory syndrome virus using semliki forest virus expression system.the orf5 gene encodes a major envelope glycoprotein (gp5), which is one of the three major proteins of porcine reproductive and respiratory syndrome virus (prrsv). the gp5 protein has been known to be a 24.5-26 kda n-glycosylated envelope protein. the gp5 is involved in inducing neutralizing antibodies. for this reason, the gp5 is primary candidate for the prrsv subunit vaccine. to produce the native form of gp5 in mammalian cells, we have cloned the orf5 gene from prrsv cnv-1 into the semliki f ...200214614267
risk factors for infection of sow herds with porcine reproductive and respiratory syndrome (prrs) virus.in 1992, the porcine reproductive and respiratory syndrome virus (prrsv) of european type (prrsv-eu) was introduced in denmark. by 1996, the virus had spread to approximately 25% of the danish herds. in january 1996, a modified-live vaccine based on the american type of the virus (prrsv-us) was used in replacement boars for danish artificial insemination (ai) centres and from july 1996, the vaccine was used in prrsv-eu infected herds for prevention of disease. soon after vaccine introduction, pr ...200211821139
transmission of porcine reproductive and respiratory syndrome virus by needles. 200211838995
in vitro and in vivo expression of foreign genes by transmissible gastroenteritis coronavirus-derived minigenomes.a helper-dependent expression system based on transmissible gastroenteritis coronavirus (tgev) has been developed using a minigenome of 3.9 kb (m39). expression of the reporter gene beta-glucuronidase (gus) (2-8 microg per 10(6) cells) and the porcine respiratory and reproductive syndrome virus (prrsv) orf5 (1-2 microg per 10(6) cells) has been shown using a tgev-derived minigenome. gus expression levels increased about eightfold with the m.o.i. and were maintained for more than eight passages i ...200211842252
kissing interaction between 3' noncoding and coding sequences is essential for porcine arterivirus rna replication.we used an infectious cdna clone of porcine reproductive and respiratory syndrome virus (prrsv) to investigate the presence of essential replication elements in the region of the genome encoding the structural proteins. deletion analysis showed that a stretch of 34 nucleotides (14653 to 14686) within orf7, which encodes the nucleocapsid protein, is essential for rna replication. strand-specific reverse transcription-pcr analysis of viral rna isolated from transfected bhk-21 cells revealed that t ...200211773426
immunological responses of swine to porcine reproductive and respiratory syndrome virus infection.the immunology of porcine reproductive and respiratory syndrome virus (prrs) begins with an initial encounter of prrsv with the pig. regardless of the route of entry of prrsv--via inhalation, intramuscular vaccination, insemination, or other routes--productive infection occurs predominately in alveolar macrophages of the lung. thus, innate responses of the lung and the alveolar macrophage comprise the initial defense against prrsv. the virus appears not to elicit innate interferon and cytokine r ...200212513925
cytokine mrna profiles in bronchoalveolar cells of piglets experimentally infected in utero with porcine reproductive and respiratory syndrome virus: association of sustained expression of ifn-gamma and il-10 after viral clearance.an experimental model was used to investigate mrna cytokine profiles in bronchoalvolar cells (balc) from piglets, infected in utero with porcine reproductive and respiratory syndrome virus (prrsv). the balc's were analyzed for the cytokines tnf-alpha, ifn-gamma, il-8, il-10, and il-12(p40) by real-time taqman polymerase chain reaction in 2-, 4-, and 6-week-old piglets, respectively. high levels of ifn-gamma mrna was detected in all piglets, while il-10 was upregulated in 2-week-old piglets, was ...200212513926
adjuvant danger signals increase the immune response to porcine reproductive and respiratory syndrome virus.the immune response of swine to vaccination with a live, attenuated prrsv was assessed in the presence and absence of cytokine adjuvants or cholera toxin (ct) to address the hypothesis that adjuvant danger signals, that is, inflammatory cytokines and bacterial extoxin, stimulate a more robust immune response. animals received four injections of recombinant porcine il-1 and il-6, il-12 alone, or ct alone within 1 week of intramuscular administration of a vaccine strain of prrsv, ingelvac mlv. ser ...200212513927
seroprevalence of antibody to procine reproductive and respiratory syndrome virus in diagnostic submissions.during the period from january to december of 2001, a total of 3,391 swine sera were submitted to our laboratory from 256 farms for the diagnosis of porcine reproductive and respiratory syndrome (prrs). the antibody to porcine reproductive and respiratory syndrome virus (prrsv) was tested by the indirect immunofluorescent antibody (ifa) test. of the 256 farms tested, 230 farms (89.8%) were positive for the prrsv antibody. the overall seroprevalence of the prrsv antibody was 52.1% (1765/3391). mo ...200212514325
[expression of porcine interferon-gamma gene in pichia pastoris and its effect of inhibiting porcine reproductive and respiratory syndrome virus].in order to develop recombinant porcine interferon-gamma (rpoifn-gamma) to prevent porcine viral infection, poifn-gamma cdna lacking the signal peptide was expressed in pichia pastoris gs115 strain, and the effect of rpoifn-gamma on porcine reproductive and respiratory syndrome virus (prrsv) was investigated. the poifn-gamma gene was inserted into integrative vector phil-s1, and the recombinant gs115 strain (phil-s1/poifn-gamma) was constructed by homologues recombinant. the rpoifn-gamma protein ...200212674637
a comparison of virus isolation, immunohistochemistry, fetal serology, and reverse-transcription polymerase chain reaction assay for the identification of porcine reproductive and respiratory syndrome virus transplacental infection in the fetus.virus isolation (vi), immunohistochemistry (ihc), fetal serology, and reverse-transcription polymerase chain reaction assay (rt-pcr) were performed on samples from 107 fetuses comprising 10 litters taken from sows experimentally infected with porcine reproductive and respiratory syndrome virus (prrsv). in addition to comparing the relative sensitivity and specificity of each test, rt-pcr was evaluated with respect to the relative suitability of thoracic fluids and tissues as samples, the effects ...200212680637
the diagnostic sensitivity of immunohistochemistry for the detection of porcine reproductive and respiratory syndrome virus in the lung of vaccinated and unvaccinated swine.immunohistochemistry (ihc) is used routinely to detect porcine reproductive and respiratory syndrome virus (prrsv) in the lung of nursery and grow/finish pigs with respiratory disease and has been reported to be highly specific (100%) but only moderately sensitive (67%). when multiple sections of lung are examined from field cases of porcine pneumonia, it is common to detect prrsv antigen in only 1 or 2 of the sections. this study was undertaken to determine the impact of the number of lung sect ...200212680638
detection and differentiation of north american and european genotypes of porcine reproductive and respiratory syndrome virus in formalin-fixed, paraffin-embedded tissues by multiplex reverse transcription-nested polymerase chain reaction.north american and european genotypes of porcine reproductive and respiratory syndrome virus (prrsv) were distinguished in formalin-fixed, paraffin-embedded tissues from prrsv-infected pigs by multiplex reverse transcription-nested polymerase chain reaction (rt-npcr). a method based on xylene deparaffinization followed by proteinase k digestion yielded rna of quality for reliable and consistent rt-npcr analyses. the prrsv nucleic acid was detected in lung, mediastinal lymph node, tonsil, and liv ...200212680645
failure of porcine reproductive and respiratory syndrome virus to replicate in porcine endothelial cell cultures.clinical, gross, and microscopic pathologic and immunohistochemical findings in pigs infected with porcine reproductive and respiratory syndrome virus (prrsv) suggest that prrsv may replicate in endothelial cells. endothelial cell cultures from porcine aorta and pulmonary artery were tested for susceptibility to various strains of prrsv. cultures were identified as endothelium by light microscopy and immunohistochemical staining for p-selectin and von willebrand factor. five strains of prrsv, i. ...200212680651
postweaning multisystemic wasting syndrome of pigs in korea: prevalence, microscopic lesions and coexisting microorganisms.a retrospective study was performed on natural cases of postweaning multisystemic wasting syndrome (pmws), recorded from january 1999 to december 2000, to determine the prevalence, microscopic lesions, and other coexisting pathogens associated with pmws. pmws is diagnosed based on three criteria: the presence of clinical signs (retardation of growth), characteristic microscopic lesions (granulomatous inflammation and inclusion body), and the presence of porcine circovirus (pcv)-2 within these le ...200211853147
characterization of regions in the gp5 protein of porcine reproductive and respiratory syndrome virus required to induce apoptotic cell death.expression of the gp5 protein of porcine reproductive and respiratory syndrome virus in mammalian cells using a recombinant vaccinia virus has been shown to induce strong cytotoxicity due to apoptotic death. we have now developed a transient expression system that allows the observation and quantitation of the cell death due to gp5 synthesis, taking advantage of the reduction that this protein induces in the expression of two different co-transfected reporter genes. in this way, we are able to s ...200211864744
infectious agents identified in pigs with multifocal interstitial nephritis at slaughter.one kidney was taken from each of 100 pigs at slaughter; 50 had gross lesions of multifocal interstitial nephritis and 50 had no gross lesions. forty-nine of the affected kidneys had lesions that were characterised by the presence of either a few randomly distributed or numerous widely disseminated pale foci, 1 to 3 mm in diameter, on the cortical surface (white-dotted kidneys). microscopically, these focal inflammatory lesions often had a distinct lymphofollicular pattern (follicular nephritis) ...200211871667
experimental inoculation of conventional pigs with porcine reproductive and respiratory syndrome virus and porcine circovirus 2.postweaning multisystemic wasting syndrome (pmws) is a disease of nursery and fattening pigs characterized by growth retardation, paleness of the skin, dyspnea, and increased mortality rates. porcine circovirus 2 (pcv2) has been demonstrated to be the cause of pmws. however, other factors are needed for full development of the syndrome, and porcine reproductive and respiratory syndrome virus (prrsv) infection has been suggested to be one of them. twenty-four conventional 5-week-old pigs were dis ...200211884547
characterization of the carrier state in porcine reproductive and respiratory syndrome virus infection.porcine reproductive and respiratory syndrome (prrs) virus infection results in clinically normal, but persistently infected animals. an understanding of the carrier state is necessary for prevention, control and/or elimination of prrs virus. the objective of this experiment was to estimate the proportion of prrs virus carriers over time and determine which combination of sample and diagnostic assay could most effectively identify persistently infected animals. sixty 3-week-old pigs were inocula ...200211900956
identification of neutralizing and nonneutralizing epitopes in the porcine reproductive and respiratory syndrome virus gp5 ectodomain.after infection of swine with porcine reproductive and respiratory syndrome virus (prrsv), there is a rapid rise of prrsv-specific nonneutralizing antibodies (nna), while neutralizing antibodies (na) are detectable not sooner than 3 weeks later. to characterize neutralizing epitopes, we selected phages from a 12-mer phage display library using anti-prrsv neutralizing monoclonal antibody (mab) isu25-c1. in addition, phages carrying peptides recognized by swine antibodies with high seroneutralizin ...200211932389
involvement of the matrix protein in attachment of porcine reproductive and respiratory syndrome virus to a heparinlike receptor on porcine alveolar macrophages.the porcine reproductive and respiratory syndrome virus (prrsv) has a very restricted tropism for well-differentiated cells of the monocyte-macrophage lineage, which is probably determined by specific receptors on these cells. in this study, the importance of heparinlike molecules on porcine alveolar macrophages (pam) for prrsv infection was determined. heparin interacted with the virus and reduced infection of pam up to 92 or 88% for the american and european types of prrsv, respectively. other ...200211932397
evolution of porcine reproductive and respiratory syndrome virus during sequential passages in pigs.porcine reproductive and respiratory syndrome (prrs) viruses are recognized as possessing a high degree of genetic and antigenic variability. viral diversity has led to questions regarding the association of virus mutation and persistent infection in the host and has raised concerns vis-à-vis protective immunity, the ability of diagnostic assays to detect novel variants, and the possible emergence of virulent strains. the purpose of this study was to describe ongoing changes in prrs virus during ...200211967292
quantification of transmission in one-to-one experiments.we study the statistical inference from data on transmission obtained from one-to-one experiments, and compare two algorithms by which the reproduction ratio can be quantified. the first algorithm, the transient state (ts) algorithm, takes the time course of the epidemic into account. the second algorithm, the final size (fs) algorithm, does not take time into account but is based on the assumption that the epidemic process has ended before the experiment is stopped. the fs algorithm is a limiti ...200212002537
expression of tumour necrosis factor-alpha is associated with apoptosis in lungs of pigs experimentally infected with porcine reproductive and respiratory syndrome virus.expression of tumour necrosis factor (tnf)-alpha and its association with apoptosis was examined in lungs from pig experimentally inoculated with porcine reproductive and respiratory syndrome virus (prrsv). the tnf-alpha nucleic acid was detected in prrsv-infected alveolar macrophages by reverse transcription-polymerase chain reaction (rt-pcr). the tnf-alpha antigen was detected in alveolar macrophages by immunohistochemisty. dna fragmentation in apoptotic cells was detected by in situ terminal ...200212002637
porcine b-cells recognize epitopes that are conserved between the structural proteins of american- and european-type porcine reproductive and respiratory syndrome virus.by selecting phage display libraries with immune sera from experimentally infected pigs, porcine b-cell epitopes in the open reading frame (orf) 2, 3, 5 and 6 proteins of european-type porcine reproductive and respiratory syndrome virus (prrsv) were identified. the sequences of all the epitopes were well conserved in european-type prrsv and even between european- and american-type prrsv. accordingly, sera from pigs infected with american-type prrsv cross-reacted with the european-type epitopes. ...200212029156
autoantibodies against golgi apparatus induced by arteriviruses.members of the genus arterivirus within the monogeneric family arteriviridae are lactate dehydrogenase-elvating virus (ldv), porcine reproductive and respiratory syndrome virus (prrsv), equine arteritis virus (eav) and simian hemorrhagic fever virus. in ldv-infected mice the appearance of autoantibodies against golgi-antigen dominated the early immune response. shared antigenicity between ldv and golgi-antigen of normal cells could not be demonstrated. monoclonal antibodies (mabs) reacted either ...200212030432
porcine reproductive and respiratory syndrome virus-induced cell death exhibits features consistent with a nontypical form of apoptosis.porcine reproductive and respiratory syndrome virus (prrsv), an arterivirus, belongs to a group of rna viruses that are cytopathic for macrophages and establish persistent infections. apoptosis is the presumed mechanism of cell death in monkey kidney cell lines and porcine alveolar macrophages after infection with european prrsv isolates. however, evidence from in vivo and in vitro studies using north american strains have failed to identify apoptosis in cells supporting virus replication and su ...200212034480
first report of post-weaning multisystemic wasting syndrome and porcine dermatitis and nephropathy syndrome in pigs in greece.post-weaning multisystemic wasting syndrome (pmws) and porcine dermatitis and nephropathy syndrome (pdns) are two recently described conditions of pigs at the late nursery and fattening stages. the aim of this short communication was to describe the first reported occurrence of these conditions and of porcine circovirus type 2 (pcv2) infection in greece. the clinical signs, gross post-mortem changes and histopathological changes observed in affected pigs, were similar to those previously describ ...200212069275
in vivo studies on cytokine involvement during acute viral respiratory disease of swine: troublesome but rewarding.the early cytokines interferon-alpha (ifn-alpha), tumour necrosis factor-alpha (tnf-alpha), interleukin-1, -6 and -8 (il-1, -6, -8) are produced during the most early stage of an infection. the activities of these cytokines have been studied extensively in vitro and in rodents, but in vivo studies on the role of these cytokines in infectious diseases of food animals are few. this review concentrates on in vivo studies of cytokine involvement in infectious respiratory diseases of swine, with an e ...200212072230
continuous porcine cell lines developed from alveolar macrophages: partial characterization and virus susceptibility.porcine monomyeloid cell lines were established following transfection of primary porcine alveolar macrophage cultures with plasmid psv3neo, carrying genes for neomycin resistance and sv40 large t antigen. the parental clone 3d4 exhibited a relatively rapid doubling time (25.5 h), high plating efficiency and mixed phenotype with respect to growth on a solid support. single cell cloning of the 3d4 parent resulted in establishment of several cell lines; three of them designated 3d4/2, 3d4/21 and 3 ...200212088830
porcine reproductive and respiratory syndrome (prrs) with special reference to clinical aspects and diagnosis. a review.after a short introduction on porcine reproductive and respiratory syndrome (prrs) regarding the history, the first occurrence in several countries, and the causal virus, designated lelystad virus, a description is given of the clinical aspects and several diagnostic methods. after some general remarks on the clinical aspects, the epidemic and the endemic phase of the disease are described. regarding the diagnosis, special attention is paid to the detection of antibodies and of the prrs virus (p ...200212095084
porcine reproductive-respiratory syndrome virus infection predisposes pigs for respiratory signs upon exposure to bacterial lipopolysaccharide.this study examined whether an infection with porcine reproductive and respiratory syndrome virus (prrsv) potentiates respiratory signs upon exposure to bacterial lipopolysaccharides (lps). five-week-old conventional pigs were inoculated intratracheally with the lelystad strain of prrsv and received 5 days later one or two intratracheal lps administrations. the necessary controls were included. after lps administration, pigs were intensively monitored for clinical signs. additionally, some pigs ...200212119134
evaluation of aerosol transmission of porcine reproductive and respiratory syndrome virus under controlled field conditions.the aim of this study was to determine whether porcine reproductive and respiratory syndrome virus (prrsv) could be transmitted by aerosol under field conditions. a total of 210 five-month-old prrsv-negative pigs were housed in a mechanically ventilated finishing facility containing 11 pens. pen 1 contained 10 pigs (indirect contact controls) and pen 2 remained empty, providing a barrier of 2.5 m from the remaining pigs in pens 3 to 11. fifteen or 16 of the pigs in each of pens 3 to 11 were infe ...200212120923
prevalence of antibodies to classical swine fever, aujeszky's disease, porcine reproductive and respiratory syndrome, and bovine viral diarrhoea viruses in wild boars in croatia.during the hunting season in february 1999, a total of 44 blood samples were collected from wild boars shot in the area of moslavacka gora. these blood samples were examined by enzyme immunoassay for the presence of antibodies to classical swine fever (csfv), aujeszky's disease (adv), bovine viral diarrhoea (bvdv), and porcine reproductive and respiratory syndrome (prrsv) viruses. out of 44 serum samples examined, 17 (38.63%) were positive for csfv, 24 (54.54%) were positive for adv and two (4.5 ...200212121047
identification of radically different variants of porcine reproductive and respiratory syndrome virus in eastern europe: towards a common ancestor for european and american viruses.we determined 22 partial porcine reproductive and respiratory syndrome virus (prrsv) orf5 sequences, representing pathogenic field strains mainly from poland and lithuania, and two currently available european-type live prrsv vaccines. also, the complete orf7 of two lithuanian and two polish strains was sequenced. we found that polish, and in particular lithuanian, prrsv sequences were exceptionally different from the european prototype, the lelystad virus, and in addition showed a very high nat ...200212124450
functional properties of the predicted helicase of porcine reproductive and respiratory syndrome virus.porcine reproductive and respiratory syndrome virus (prrsv) is a member of the positive-strand rna virus family arteriviridae. although considerable research has focused on this important pathogen, little is known about the function of most prrsv proteins. to examine characteristics of putative nonstructural proteins (nsp) encoded in orf1b, which have been identified by nucleotide similarity to domains of equine arteritis virus, defined genomic regions were cloned and expressed in the prset expr ...200212127789
mechanical transmission of porcine reproductive and respiratory syndrome virus by mosquitoes, aedes vexans (meigen).the objective of this study was to determine whether porcine reproductive and respiratory syndrome virus (prrsv) could be transmitted to naive pigs by mosquitoes following feeding on infected pigs. during each of 4 replicates, mosquito-to-pig contact took place on days 5, 6, and 7 after prrsv infection of the donor pig. a total of 300 mosquitoes [aedes vexans (meigen)] were allowed to feed on each viremic donor pig, housed in an isolation room. after 30 to 60 s, feeding was interrupted, and the ...200212146891
assessing the duration of persistence and shedding of porcine reproductive and respiratory syndrome virus in a large population of breeding-age gilts.porcine reproductive and respiratory syndrome virus (prrsv) is an rna virus in the order nidovirales, family arteriviridae, genus arterivirus. the virus induces a prolonged viremia, replicates in macrophages, and produces persistent infection. the purpose of this study was to determine if prrsv could persist for 90 d or more in a large population of breeding-age gilts housed under environmental conditions typical of commercial swine production and to determine if experimentally infected gilts co ...200212146892
a survey of agents associated with neonatal diarrhea in iowa swine including clostridium difficile and porcine reproductive and respiratory syndrome virus.this survey was undertaken to determine the relative frequency of agents that are currently associated with neonatal diarrhea in swine, including clostridium difficile and porcine reproductive and respiratory syndrome virus (prrsv). the subjects for this study were the first 100 live 1-7-day-old piglets submitted to the iowa state university veterinary diagnostic laboratory with a clinical signalment of diarrhea, beginning on january 1, 2000. the evaluation of each pig included bacterial culture ...200212152806
restriction fragment length polymorphism of porcine reproductive and respiratory syndrome viruses recovered from ontario farms, 1998-2000.from january 1998 to july 2000, 2,456 clinical samples, including lung, tonsil, lymph node, and serum, from 760 cases submitted to the animal health laboratory, ontario, canada, were tested for porcine reproductive and respiratory syndrome viruses (prrsv) using reverse transcriptase polymerase chain reaction (rt-pcr) and rt-pcr product restriction fragment length polymorphism (rflp) analysis. a total of 516 samples from 284 cases were rt-pcr positive for the prrsv open reading frame (orf) 7 sequ ...200212152819
the genetic diversity of european type prrsv is similar to that of the north american type but is geographically skewed within europe.porcine reproductive and respiratory syndrome virus (prrsv) is a recently emerged pathogen. two prrsv genotypes exist, north american and european, which are only 55-70% identical at the nucleotide level. previous studies have shown high nucleotide diversity in the north american genotype and low nucleotide diversity in the european genotype. here, we analyzed the orf5 and orf7 genes for a large number of new european type prrsv isolates in conjunction with existing database sequences. this new ...200212167339
evaluation of enzyme-linked immunosorbent assay (elisa) and immunofluorescent antibody (ifa) test for the detection of porcine reproductive and respiratory syndrome virus (prrsv) antibody in pigs from conventional farms.to evaluate the immunofluorescent antibody (ifa) test and enzyme-linked immunosorbent assay (elisa) for detecting the porcine reproductive and respiratory syndrome virus (prrsv) antibody, conventional pigs in prrsv-positive and -negative commercial farms were examined. antibody development patterns in elisa and ifa tests were compared in 3 week old piglets experimentally infected with the prrsv. the virus was detected from 2 days post infection (pi) and then the antibody titers and s/p ratios ro ...200212185311
antibodies to selected viral and bacterial pathogens in european wild boars from southcentral spain.serum samples from 78 european wild boars (sus scrofa) harvested during the 1999-2000 hunting season were tested for antibodies to brucella spp., classical swine fever virus, erysipelothrix rhusiopathiae, haemophilus parasuis, leptospira interrogans serovar pomona, mycoplasma hyopneumoniae, pseudorabies virus (prv), porcine parvovirus (ppv), porcine reproductive and respiratory syndrome virus, salmonella serogroups b, c, and d, streptococcus suis, and swine influenza virus (siv) serotypes h1n1 a ...200212238391
phosphorylation of the porcine reproductive and respiratory syndrome virus nucleocapsid protein.porcine reproductive and respiratory syndrome virus (prrsv) is a cytoplasmic rna virus with the unique or unusual feature of having a nucleocapsid (n) protein that is specifically transported to the nucleolus of virus-infected cells. in this communication, we show that the n protein is a phosphoprotein. phosphoamino acid analysis of authentic and recombinant n proteins demonstrated that serine residues were exclusively phosphorylated. the pattern of phosphorylated n protein cellular distribution ...200212239338
expression of interferon-gamma and tumour necrosis factor-alpha in pigs experimentally infected with porcine reproductive and respiratory syndrome virus (prrsv).the expression of mrna encoding interferon-gamma (ifn-gamma) and tumour necrosis factor-alpha (tnf-alpha) was studied, by reverse transcription-polymerase chain reaction and by in-situ hybridization with a non-radioactive digoxigenin-labelled probe, in formalin-fixed, paraffin wax-embedded lung tissue from pigs experimentally infected with a korean isolate (north american genotype) of prrsv. both ifn-gamma and tnf-alpha mrna were detected in the lung as early as 1 day post-inoculation (dpi) and ...200212354520
effects of different us isolates of porcine reproductive and respiratory syndrome virus (prrsv) on blood and bone marrow parameters of experimentally infected pigs.seventy five-week-old, crossbred, caesarean-derived, colostrum-deprived pigs were randomly divided into five groups of 14 pigs and assigned one of five treatments: the intranasal inoculation of 1 (5.7) tcid50 of one of four plaque-purified isolates of porcine reproductive and respiratory syndrome virus (prrsv) (vr2385, vr2431, isu-984 and isu-22), or uninfected cell culture and media. haematological variables were measured for 21 days and bone marrow was analysed when the pigs were killed three, ...200212371690
experimental airborne transmission of porcine reproductive and respiratory syndrome virus and bordetella bronchiseptica.experiments were designed to determine if porcine reproductive and respiratory syndrome virus (prrsv) or bordetella bronchiseptica could be transmitted through indirect airborne contact. three principal pigs were infected with prrsv, b. bronchiseptica or both. five days after the principal pigs were challenged, the three principal pigs and one direct-contact pig were placed into one isolation tent together, and three indirect-contact pigs were placed into another isolation tent which received it ...200212383636
viral pharmacovigilance study of haemophiliacs receiving porcine factor viii.porcine factor viii (fviii; hyate:c; speywood biopharm ltd, uk) has been used since 1980 for the treatment both of patients with acquired haemophilia and those with congenital haemophilia and inhibitory antibodies. each batch is extensively screened using cell-culture techniques to confirm the absence of viruses. the production process does not incorporate specific virucidal treatment steps, such as heat treatment or the addition of a solvent/detergent mixture. low levels of porcine parvovirus w ...200212410650
nucleocapsid protein-based enzyme-linked immunosorbent assay for detection and differentiation of antibodies against european and north american porcine reproductive and respiratory syndrome virus.two types of porcine reproductive and respiratory syndrome virus (prrsv) have been reported, the european type (eu prrsv) and the north american type (us prrsv). we developed a dual enzyme-linked immunosorbent assay (elisa) for the simultaneous detection and differentiation of serum antibodies directed against either of the two prrsv types. this tandem prrs elisa is based on affinity-purified recombinant nucleocapsid protein expressed in escherichia coli. sensitivity and specificity were assesse ...200212414748
cytokine profiles in peripheral blood mononuclear cells and lymph node cells from piglets infected in utero with porcine reproductive and respiratory syndrome virus.the aim of the present study was to investigate at 2, 4, and 6 weeks after birth cytokine expression by peripheral blood mononuclear cells and bronchial lymph node cells from piglets infected in utero with porcine reproductive and respiratory syndrome virus (prrsv). technically, by flow cytometry we were able to measure gamma interferon (gamma-ifn), tumor necrosis factor alpha (tnf-alpha), interleukin-4 (il-4), and il-8 levels. in general, we found increases in the percentages of il-4-, gamma-if ...200212414754
comparison of molecular and biological characteristics of a modified live porcine reproductive and respiratory syndrome virus (prrsv) vaccine (ingelvac prrs mlv), the parent strain of the vaccine (atcc vr2332), atcc vr2385, and two recent field isolates of prrsv.the objectives of this study were to compare the molecular and biological characteristics of recent porcine reproductive and respiratory syndrome virus (prrsv) field isolates to those of a modified live virus (mlv) prrs vaccine and its parent strain. one hundred seventeen, 4-week-old pigs were randomly assigned to six groups. group 1 (n = 20) served as sham-inoculated negative controls, group 2 (n = 19) was inoculated with ingelvac prrs mlv vaccine, group 3 (n = 20) was inoculated with the paren ...200212414926
stable and long-lasting immune response in horses after dna vaccination against equine arteritis virus.equine arteritis virus (eav) is the causative agent of the equine viral arteritis. it is a small rna virus with a linear, non-segmented plus rna genome. eav is a member of the arteriviridae family that includes porcine reproductive and respiratory syndrome virus (prssv), simian haemorrhagic fever virus (shfv) and lactate dehydrogenase virus (ldv). the viral transmission is via respiratory and reproductive routes. clinical signs in horses vary, and severe infection can lead to abortions in pregna ...200212418451
mechanical transmission of porcine reproductive and respiratory syndrome virus throughout a coordinated sequence of events during cold weather.using a field-based model, mechanical transmission of porcine reproductive and respiratory syndrome virus (prrsv) wa assessed throughout a coordinated sequence of events that replicated common farm worker behavior during cold weather (< 0 degrees c). the model involved fomites (boots and containers), vehicle sanitation, transport, and the movement of personnel. a field strain of prrsv was inoculated into carriers consisting of snow and water, and carriers were adhered to the undercarriage of a v ...200212418778
case-control study on the association of porcine circovirus type 2 and other swine viral pathogens with postweaning multisystemic wasting syndrome.a field-based case-control study was conducted to assess the strength of association of porcine circovirus type 2 (pcv2) and some major swine viruses with postweaning multisystemic wasting syndrome (pmws). cases were defined as individual pigs with a clinical history of progressive weight loss and histopathological lesions characteristic of pmws. controls were pigs without clinical signs and histopathological lesions typical of pmws. a total of 31 cases and 56 controls was identified from diagno ...200212423025
effect of formalin fixation on the immunohistochemical detection of prrs virus antigen in experimentally and naturally infected pigs.the purpose of this study was to determine the effect of formalin fixation on the immunohistochemical detection of porcine reproductive and respiratory syndrome (prrs) viral antigen in lungs of experimentally and naturally infected pigs. in separate trials, five 24-day-old pigs and six 10-day-old pigs were housed as separate groups in isolation and inoculated intranasally with 10(5.5) tcid50 of an isolate of prrs virus (prrsv; p129). the older and younger pigs were euthanatized at 7 and 10 days ...200212423035
porcine circovirus type 2 (pcv-2) coinfections in us field cases of postweaning multisystemic wasting syndrome (pmws).the prevalence of different pathogens detected in combination with porcine circovirus type 2 (pcv-2) was studied retrospectively in field cases of postweaning multisystemic wasting syndrome (pmws) diagnosed at the iowa state university veterinary diagnostic laboratory, ames, iowa, between january 2000, and september 2001. the presence of pcv-2 antigen in lymphoid tissues and/or lung, demonstrated by immunohistochemistry, together with moderate to severe lymphoid depletion and/or granulomatous ly ...200212423038
passive transfer of virus-specific antibodies confers protection against reproductive failure induced by a virulent strain of porcine reproductive and respiratory syndrome virus and establishes sterilizing immunity.immune mechanisms mediating protective immunity against porcine reproductive and respiratory syndrome virus (prrsv) are not well understood. the prrsv-specific humoral immune response has been dismissed as being ineffective and perhaps deleterious for the host. the function of prrsv antibodies in protective immunity against infection with a highly abortifacient strain of this virus was examined by passive transfer experiments in pregnant swine. all of a group of pregnant gilts (n = 6) that recei ...200212429512
thymocyte and peripheral blood t lymphocyte subpopulation changes in piglets following in utero infection with porcine reproductive and respiratory syndrome virus.piglets infected in utero with porcine reproductive and respiratory syndrome virus (prrsv) are born severely immunocompromised. in this article we more closely examine the effects of in utero prrsv infection on circulating and thymic t cell populations. numbers of cd4+, cd8+, and dual-positive lymphocytes were quantitated in circulation and in the thymus during the 2 weeks following birth. at birth we found that the number of circulating lymphocytes was suppressed by 60%. lymphocyte numbers were ...200212441080
assessment of porcine reproductive and respiratory syndrome virus rna load in sera and tissues during acute infection.porcine reproductive and respiratory syndrome virus (prrsv) rna load in sera and tissues during acute phase of infection was evaluated using a pcr- based quantitative assay. more than 80% of infected pigs (21/25) showed the peak level of viral rna concentrations in serum (up to 8.6 x 10(8) copies/ml) at day 5 postinfection (pi), and started to clear the virus from the systemic circulation thereafter. regression analysis using the viral rna concentrations in sera obtained from days 5 to 14 pi sho ...200212441676
localization of porcine reproductive and respiratory syndrome virus infection in boars by in situ riboprobe hybridization.the capability of porcine reproductive and respiratory syndrome virus (prrsv) to be shed in semen for extended periods of time has been suggested to be a principal factor for viral transmission via insemination. in attempts to gain insights into the mechanism of prrsv persistence in boars, tissue distribution and sites of viral infection were investigated by in situ hybridization (ish) using digoxigenin-labeled rna probe and the ish results were compared with those of reverse transcription-neste ...200212441677
modified indirect porcine circovirus (pcv) type 2-based and recombinant capsid protein (orf2)-based enzyme-linked immunosorbent assays for detection of antibodies to pcv.postweaning multisystemic wasting syndrome of swine associated with porcine circovirus (pcv) is a recently reported and economically important disease. simple and reliable diagnostic methods are needed for detecting antibodies to pcv type 2 (pcv2) for monitoring of pcv infection. here, we report the development of two modified indirect enzyme-linked immunosorbent assays (elisas): a pcv2 elisa based on cell-culture-propagated pcv2 and an orf2 elisa based on recombinant major capsid protein. pcv2 ...200211777826
porcine reproductive and respiratory syndrome virus (prrsv) infection status in pigs naturally affected with post-weaning multisystemic wasting syndrome (pmws) in spain.the purpose of the study reported here was to determine the prevalence of porcine reproductive and respiratory syndrome virus (prrsv) in pigs affected with post-weaning multisystemic wasting syndrome (pmws), a disease believed to be caused by porcine circovirus type 2 (pcv2). from may 1997 to february 2000, pmws was diagnosed in 277 pigs (from 120 farms) submitted to the veterinary pathology diagnostic service, veterinary school of barcelona, spain. in each case, the pmws diagnosis was based on ...200211792488
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 ...200211731155
differentiation of a vero cell adapted porcine epidemic diarrhea virus from korean field strains by restriction fragment length polymorphism analysis of orf 3.a porcine epidemic diarrhea virus (pedv) designated dr13 was isolated in vero cells and serially passaged by level 100. the virus was titrated at regular intervals of the passage level. open reading frame (orf) 3 sequences of the virus at passage levels 20, 40, 60, 80, and 100 were aligned and compared using a computer software program. suitability of the restriction fragment length polymorphism (rflp) analysis for differentiating the virus from other korean field strains was investigated. the d ...200312706667
virological kinetics and immunological responses to a porcine reproductive and respiratory syndrome virus infection of pigs at different ages.the objective of this study was to measure the effect of two variables (pig age and virus strain) on selected responses (clinical signs, viraemia, virus excretion and seroconversion) of pigs following exposure to porcine reproductive and respiratory syndrome (prrs) virus. therefore, young (6 till 8 weeks old) and old (6 months old) pigs were infected with 3 different prrsv strains, i.e. lv ter huurne (lvth), lv4.2.1 and sdsu#73. regardless of the strain used for exposure, young pigs were more su ...200312706683
Refresh
firstprev
12345678910...
nextlast
Displaying items 401 - 500 of 2577