Publications

genome sequence determinations and analyses of novel circoviruses from goose and pigeon.	the genomes of novel circoviruses from goose and pigeon, which were isolated using degenerate primer and inverse primer pcr methods, were cloned and sequenced. comparative nucleotide (nt) sequence analyses showed that the goose circovirus (gcv) and pigeon circovirus (picv) possessed genomes which were 1821 and 2037 or 2036 nt, respectively, and which had features in common with the genomes of porcine circoviruses types 1 and 2 (pcv1, pcv2) and psittacine beak and feather disease virus (bfdv), su ...	2001	11485403
optimized protocols for the detection of porcine circovirus 2 dna from formalin-fixed paraffin-embedded tissues using nested polymerase chain reaction and comparison of nested pcr with in situ hybridization.	optimized dna extraction method and nested polymerase chain reaction (pcr) were developed for the detection of porcine circovirus 2 (pcv2) from formalin-fixed, paraffin-embedded tissues. conventional pcr, nested pcr, and in situ hybridization methods were also compared for the detection of pcv2 in archival tissues. a method based on xylene deparaffinization followed by proteinase k digestion yielded dna of sufficient quality for pcr analyses reliably and consistently. twenty-six (70%) of the 37 ...	2001	11226557
porcine circovirus 2 infection in swine foetuses inoculated at different stages of gestation.	the ability of porcine circovirus 2 (pcv2) to replicate and cause pathologic abnormalities in foetuses at selected time points of gestation was examined in this study. two foetuses were inoculated in utero in each of two sows at 57, 75 and 92 days of gestation, respectively, with pcv2 (1121). the remaining foetuses were left uninoculated to assess whether intra-uterine spread occurred. twenty-one days after inoculation, the foetuses were collected and examined for gross lesions and for virus and ...	2001	11557157
nucleotide sequence analysis of a novel circovirus of canaries and its relationship to other members of the genus circovirus of the family circoviridae.	the circular, single-stranded dna genome of a novel circovirus of canaries, tentatively named canary circovirus (cacv), was cloned and sequenced. sequence analysis indicated that the genome was 1952 nucleotides (nt) in size and had the potential to encode three viral proteins, including the putative capsid and replication-associated (rep) proteins. the cacv genome shared greatest sequence similarity (58.3% nt identity) with the newly characterized columbid circovirus (cocv) and was more distantl ...	2001	11602793
[three cases of postweaning multisystemic wasting syndrome (pmws) due to porcine circovirus type 2 (pcv 2) in switzerland].	porcine circovirus type 2 (pcv 2) was found in three five- and nine-week-old pigs from two feeder pig producer farms. clinical signs were persistent diarrhea and wasting. the animals showed histomorphologic changes characteristic for "postweaning multisystemic syndrome" (pmws). one animal had the typical basophilic intracytoplasmatic circoviral inclusion bodies in the peyer's patches of the ileum. circoviral dna was detected in the lymphatic organs as well as in the liver. this case report is th ...	2001	11407249
immunohistochemical characterisation of the lymph node reaction in pig post-weaning multisystemic wasting syndrome (pmws).	the superficial inguinal lymph nodes of 10 piglets which had died spontaneously of post-weaning multisystemic wasting syndrome (pmws), in which the porcine circovirus type ii (pcv-ii) genome was revealed by pcr, were submitted to immunohistochemical investigation for cd4, cd8, igm, mac387, s-100 protein, vimentin and f-viii-ra and compared with three normal cases. the lymph node reaction was graded as initial, intermediate and end stage according to histological criteria. in the initial and inte ...	2001	11604161
avian skin diseases.	avian dermatology is an important part of avian practice. feather plucking, or self-mutilation, is one of the most common and challenging syndromes seen in avian practices, yet our understanding of it has developed piecemeal. psittacine circovirus, which causes psittacine beak and feather disease, can devastate breeding programs and cause masked distress to new bird owners and their young birds. cutaneous neoplasms are increasing in incidence as veterinarians are seeing more older bird patients.	2001	11480362
differentiation of porcine circovirus 1 and 2 in formalin-fixed, paraffin-wax-embedded tissues from pigs with postweaning multisystemic wasting syndrome by in-situ hybridisation.	non-radioactive digoxigenin (dig)-labelled probes that can differentiate porcine circovirus (pcv) 1 from pcv2 in formalin-fixed, paraffin-wax-embedded tissues by in-situ hybridisation were developed. a 349 base pair (bp) dna fragment from open reading frame (orf) 1 of pcv1 and a 481 bp dna fragment from orf2 of pcv2 generated by polymerase chain reaction (pcr) were used as pcv1 and pcv2 probes, respectively. a specific dig-labelled pcv1 dna probe did not hybridise with pcv2-infected pk-15 cells ...	2001	11676625
detection of circovirus infection in pigeons by in situ hybridization using cloned dna probes.	degenerate primers were designed based on known sequence information for the circoviruses psittacine beak and feather disease virus and porcine circovirus and applied by polymerase chain reaction (pcr) to known virus-infected bursa of fabricius (bf) from a pigeon. a 548-bp dna fragment was amplified and shown to be specific to a novel circovirus, named pigeon circovirus (picv), and was used to produce sensitive and specific probes for detection of circovirus dna by in situ hybridization (ish). u ...	2001	11724137
postweaning multisystemic wasting syndrome induced after experimental inoculation of cesarean-derived, colostrum-deprived piglets with type 2 porcine circovirus.	cesarean-derived, colostrum-deprived pigs (n = 23) were inoculated intranasally and subcutaneously with a low cell culture passage of type 2 porcine circovirus. in 11 pigs, a persistent fever that lasted 7-17 days began 12-15 days after inoculation with virus. additional signs of disease in those 11 pigs included depression (11 of 11 pigs), palpable enlargement of inguinal, prefemoral, and popliteal lymph nodes (11 of 11), icterus (6 of 11), and hyperpnea (2 of 11). the remaining 12 pigs had fev ...	2001	11482594
replication of porcine circovirus type 1 requires two proteins encoded by the viral rep gene.	the rep gene of porcine circovirus type 1 (pcv1) is indispensable for replication of viral dna. truncation or introduction of point mutations into four conserved sequence motifs led to inactivation of rep as replication initiator. transcription of rep starts at nucleotide 767 +/- 10 bp. an intron (nucleotides 1176 to 1558) is removed by splicing. this leads to synthesis of a truncated protein, which was termed rep' (19.2 kda). because of a frameshift, the last 48 amino acids of rep' deviate from ...	2001	11162799
activation of the immune system is the pivotal event in the production of wasting disease in pigs infected with porcine circovirus-2 (pcv-2).	porcine circovirus (pcv)-2, a newly described single-stranded circular dna virus pathogen of swine is the cause of postweaning multisystemic wasting syndrome (pmws). in gnotobiotic piglets, pcv-2 infection alone produces asymptomatic infection without evidence of overt pmws. gnotobiotic piglets infected with pcv-2 were injected with keyhole limpet hemocyanin in incomplete freund's adjuvant (klh/icfa), and the effects on virus production and development of pmws were determined. in the first exper ...	2001	11199162
bacterial expression of an immunologically reactive pcv2 orf2 fusion protein.	the entire coding region of open reading frame 2 (orf2) of porcine circovirus 2 (pcv2) was linked to the 3'-end of the maltose-binding protein (mbp)-his(8)-tag gene. the fusion protein was expressed as soluble form after induction by isopropylthio-beta-d-galactoside. mbp-his(8)-orf2 was purified to homogeneity by immobilized metal affinity chromatography based on the interaction of the polyhistidine-tag with metal ions. expression could represent 1% of the total protein in escherichia coli, allo ...	2001	11162395
transplacental infection with pcv-2 associated with reproductive failure in a gilt.		2001	11442241
colocalization of porcine reproductive and respiratory syndrome virus and porcine circovirus 2 in porcine dermatitis and nephrology syndrome by double-labeling technique.	simultaneous detection of porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus 2 (pcv2) was achieved by a double-labeling technique using a combination of immunohistochemistry and in situ hybridization in five pigs with naturally occurring porcine dermatitis and nephropathy syndrome (pdns). both prrsv and pcv2 were isolated from a homogenate of pooled skin and kidney from three pigs. prrsv rna was demonstrated by reverse transcription polymerase chain reaction (pcr) ...	2001	11467478
multiple porcine circovirus 2-associated abortions and reproductive failure in a multisite swine production unit.	porcine circovirus type 2 was detected in several stillborn and nonviable neonatal piglets presenting with chronic passive congestion, cardiac hypertrophy, and severe diffuse myocarditis. the presence of the virus in the heart and other tissues of affected piglets was confirmed by polymerase chain reaction, immunohistochemistry, and virus isolation techniques. other reproductive losses and associated infectious agents in the herd are discussed.	2001	11467184
association of porcine circovirus 2 with reproductive failure in pigs: a retrospective study, 1995-1998.	in order to determine if vertically transmitted porcine circovirus (pcv) has played a role in reproductive failure in pigs in areas of endemic infection, archival fixed tissues were examined by polymerase chain reaction (pcr) and immunohistochemistry. tissues tested were from routine cases of abortion or reproductive failure submitted between 1995 and 1998 to the diagnostic laboratory at the western college of veterinary medicine, saskatoon. they originated from 29 high-health herds in the provi ...	2001	11467183
genetic analysis of full-length genomes and subgenomic sequences of tt virus-like mini virus human isolates.	the phylogenetic relationship between the complete genomic sequences of ten japanese and one french isolate of tt virus-like mini virus (tlmv) was investigated. analysis of the variability of the nucleotide sequences and the detection of signature patterns for overlapping genes suggested that orfs 1 and 2 are probably functional. however, this was not the case for a putative third orf, orf3. throughout the viral genome, several nucleotide or amino acid motifs that are conserved in circoviruses s ...	2001	11161277
igm-class antibodies to tt virus (ttv) in patients with acute ttv infection.	tt virus (ttv) is a human circovirus with a single-stranded, circular dna genome of 3.8 kb. a method was developed to detect igm antibodies to ttv as a serological marker for the diagnosis of acute ttv infection. igm antibodies in test sera were captured by a monoclonal antibody against igm/µ on a solid support followed by binding of igm with ttv derived from fecal extract of a ttv carrier. the presence of igm-specific ttv particles was determined by polymerase chain reaction (pcr) using nucleic ...	2001	11137475
genetic diversity of beak and feather disease virus detected in psittacine species in australia.	the complete nucleotide (nt) sequence of eight isolates of beak and feather disease virus (bfdv) obtained from a range of psittacine species with psittacine beak and feather disease (pbfd) from throughout australia were compared with the sequences of two bfdv isolates previously reported from australia (bfdv-aus) and america (bfdv-usa), respectively. all isolates had the same basic structure including the position of the open reading frames, the hairpin structure between orf1 and orf2, the nonan ...	2001	11162795
viral replication and lesions in balb/c mice experimentally inoculated with porcine circovirus isolated from a pig with postweaning multisystemic wasting disease.	eight-week-old balb/c mice were either sham inoculated (control mice) or were inoculated intraperitoneally (ip) and intranasally (in) with a single (spcv mice) or multiple (mpcv mice) doses of porcine circovirus 2 (pcv2). four control mice and 4 spcv mice were sacrificed 7, 14, 28, and 42 days postinoculation (pi). all 4 mpcv mice were sacrificed 42 days pi. in addition, 7-day and 14-day pregnant balb/c mice were either sham inoculated (control mice) or were inoculated ip and in with a single do ...	2001	11199167
double in situ hybridization for simultaneous detection of porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus (pcv).	a double in situ hybridization method for the simultaneous detection of porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus (pcv) genomes in the same tissue section was applied to lung tissues from 9 pigs in which prrsv and pcv coinfection had been previously demonstrated. paraffin-embedded tissue sections were simultaneously hybridized with a digoxigenin-labeled antisense rna probe for prrsv and a fluorescein-labeled antisense rna probe for pcv, and hybridization ...	2001	11243366
dual infection with pcv-2 and porcine epidemic diarrhoea virus in neonatal piglets.		2001	11334076
isolation and characterization of porcine circovirus 2 from cases of sow abortion and porcine dermatitis and nephropathy syndrome.	we report the isolation and characterisation of porcine circovirus 2 (pcv2) from cases of sow abortion and porcine dermatitis and nephropathy syndrome. the results suggest that the clinical scope of pcv2 infections requires continuous re-evaluation.	2001	11402869
production, characterisation and applications of monoclonal antibodies to porcine circovirus 2.	the production, preliminary characterisation and applications of monoclonal antibodies (mabs) against six porcine circovirus 2 isolates are described. a total of 14 stable hybridomas were produced, of which 7 were characterised. all of the mabs characterised were of igg isotype. all the mabs tested reacted by iif with acetone-fixed cell cultures infected with pcv2 isolates from canada, france, spain, denmark, usa and uk. no cross-reactivity with a porcine circovirus 1 field isolate was demonstra ...	2001	11448029
nuclear localization of the orf2 protein encoded by porcine circovirus type 2.	infectious porcine circovirus type 2 (pcv2) was generated following transfection of a porcine retina cell line (vido r1) with cloned circovirus dna. expression of open reading frame 2 (orf2) was detected at 24 h postinfection and onwards increasingly throughout the infection by western blot analysis using orf2 specific polyclonal antibody. moreover, the orf2 protein was also detected in purified pcv2 virus, indicating that orf2 is a structural component of pcv2 viral capsid. nuclear localization ...	2001	11414809
lack of antibodies to porcine circovirus type 2 virus in beef and dairy cattle and horses in western canada.	porcine circovirus type 2 (pcv2) is a recently recognized agent that is consistently associated with postweaning multisystemic wasting disease in swine. there are conflicting data concerning the ability of this virus to infect and cause disease in other species. to determine if normal cattle, cattle affected with various illnesses, and normal horses in endemic areas of pcv2 infection in swine have had pcv2 infections, 100 randomly selected bovine sera, 100 equine sera, and 100 colostrum samples ...	2001	11424578
pcv-2 from emaciated pigs in mexico.		2001	11465277
tt virus in hematological disorders and bone marrow transplant recipients.	tt virus (ttv) was cloned as a possible causative agent for non a to c posttransfusion hepatitis. determination of the entire sequence of the virus revealed that the virus is the first human circovirus. the nucleotide sequence of ttv has a wide range of diversity and at least sixteen genotypes have been discovered to date. the prevalence of ttv infection in the normal population differs among countries, but exceeds 10% in several countries. most of ttv infections are not associated with hepatiti ...	2001	11426521
tissue distribution and genetic typing of porcine circoviruses in pigs with naturally occurring congenital tremors.	congenital tremors (ct) type a2 is associated with porcine circovirus (pcv) and deficient and abnormal myelin. the aim of this study was to determine the tissue distribution and genetic type of pcv in 1-2-day-old pigs with naturally occurring ct type a2 using in situ hybridization, polymerase chain reaction (pcr), and indirect fluorescent antibody tests on frozen tissue sections. ct-affected and clinically normal pigs were selected from 4 farms in the midwestern usa that were undergoing outbreak ...	2001	11243364
granulomatous enteritis and lymphadenitis in iberian pigs naturally infected with lawsonia intracellularis.	intestinal samples and/or lymph nodes of two iberian pigs from two different farms were submitted for histopathologic examination. both pigs had proliferation of ileal and/or cecal crypts with almost complete absence of goblet cells. infection by lawsonia intracellularis was demonstrated by immunohistochemistry and polymerase chain reaction assay. the mesenteric lymph node of one pig had moderate lymphocyte depletion with granulomatous inflammation of the lymph node parenchyma. histiocytes and m ...	2001	11355669
prevalence of porcine reproductive and respiratory syndrome virus, porcine circovirus type 2 and porcine parvovirus from aborted fetuses and pigs with respiratory problems in korea.	porcine reproductive and respiratory syndrome virus(prrsv)0, porcine circovirus type 2(pcv-2) and porcine parvovirus (ppv)0 infections were investigated as possible causes of the postweaning multisystemic wasting syndrome(pmws). specific primers for rt-pcr and pcr were designed for the differential detection of prrsv, pcv-2 and ppv. using pcr, these viruses were detected in homogenized tissue samples from pigs that had respiratory of reproductive problems in the time period between 1998 and 2000 ...	2001	12441689
experimental reproduction of severe disease in cd/cd pigs concurrently infected with type 2 porcine circovirus and porcine reproductive and respiratory syndrome virus.	three-week-old cesarean-derived colostrum-deprived (cd/cd) pigs were inoculated with porcine circovirus type 2 (pcv2, n = 19), porcine reproductive and respiratory syndrome virus (prrsv, n = 13), concurrent pcv2 and prrsv (pcv2/prrsv, n = 17), or a sham inoculum (n = 12) to compare the independent and combined effects of these agents. necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. by 10 dpi, pcv2/prrsv-inoculated pigs had severe dy ...	2001	11572560
rep and rep' protein of porcine circovirus type 1 bind to the origin of replication in vitro.	genome replication of porcine circovirus type 1 (pcv1) relies upon expression of the full-length protein rep and a spliced isoform (rep'), and the presence of a 111-bp genomic fragment comprising the origin of replication. using an electrophoretic mobility shift assay (emsa), the capability of both rep proteins to bind to partial fragments of the origin of replication of pcv1 was investigated in vitro. both proteins formed complexes with double-stranded dna origin fragments containing a stem-loo ...	2001	11878884
nucleotide sequence-based identification of a novel circovirus of canaries.	circovirus-like, spherical particles measuring 16 to 18 nm in diameter were detected in organ homogenates from adult canaries that had died after a short illness characterized by dullness, anorexia, lethargy and feather disorder. a polymerase chain reaction method, based on degenerate primers specific to conserved amino acid sequences in the circovirus replication-associated protein, was used to amplify dna specific to a novel circovirus, tentatively named canary circovirus (ccv). sequence analy ...	2001	19184917
pigeon circovirus infection: pathological observations and suggested pathogenesis.	pigeon circovirus infection (picv) was diagnosed by light and transmission electron microscopy in 15 birds from five lofts in western france. histopathological findings were suggestive of primary bursotropism of pigeon circovirus, followed by secondary systemic spread from the bursa of fabricius, particularly to non-bursal lymphoid organs. the last stage of the disease was associated with various secondary (particularly bacterial) infections. in situ detection of apoptosis in the bursa of fabric ...	2001	19184889
a diagnostic study on columbid circovirus infection.	a systematic study was performed to examine the frequency of columbid circovirus (cocv) infection in diseased young pigeons submitted for necropsy and its relevance to pigeon health. existing diagnostic methods were compared. among 176 diseased young pigeons examined, cocv infection was detected in 83 cases using negative contrast electron microscopy. histopathological examination allowed a clear diagnosis in only 42 pigeons. therefore, a polymerase chain reaction assay and an in situ hybridizat ...	2001	19184954
circoviruses: immunosuppressive threats to avian species: a review.	circoviruses are small, non-enveloped, icosahedral viruses that are unique among animal viruses in having circular, single-stranded dna genomes. their genomes are also the smallest possessed by animal viruses. the circovirus family currently comprises three members, chicken anaemia virus, porcine circovirus, and psittacine beak and feather disease virus, with pigeon circovirus being classified as a tentative member. infections with each of the four circoviruses are associated with potentially fa ...	2000	19184829
new pig disease in hungary: postweaning multisystemic wasting syndrome caused by circovirus (short communication).	postweaning multisystemic wasting syndrome (pmws), a new disease in hungary, was recognized in a swine herd located in southeast hungary, during the early winter of 1999. the first clinical signs of paleness, anaemia, and leanness appeared immediately after weaning, at the age of 40-50 days. pustules were frequently observed on the skin of the trunk, and signs of necrotic dermatitis were also visible. a syndrome of poor growth and wasting was characteristic of the affected pigs. a porcine circov ...	2000	11402663
fecal excretion of a novel human circovirus, tt virus, in healthy children.	the role of tt virus (ttv) as a human pathogen is unclear, as is the mode of ttv transmission. to determine the prevalence of ttv infection and the possible fecal-oral route of transmission, we analyzed fecal specimens from 67 healthy, nontransfused children for ttv dna sequences by heminested pcr, using the ng and t primer sets. the overall prevalence of ttv fecal excretion was 22.4% (15 of 67), with the t primer set (19.4%) being more sensitive than the ng primer set (10.4%). ttv prevalence ba ...	2000	11063506
utilization of a rate enhancement hybridization buffer system for rapid in situ hybridization for the detection of porcine circovirus in cell culture and in tissues of pigs with postweaning multisystemic wasting syndrome.	a rapid in situ hybridization (ish) technique for the detection of porcine circovirus (pcv) nucleic acid in cell culture and formalin-fixed paraffin-embedded tissues was developed. a fluorescein-labeled rna probe was transcribed from a plasmid containing 530 bp of the orf1 of a pcv isolated from a pig with postweaning multisystemic wasting syndrome (pmws). hybridization using standard hybridization buffer was performed at 42 c for 16 hours and was compared to hybridization using rate enhancement ...	2000	11108458
evidence of porcine circovirus infection in pigs with wasting disease syndrome from 1985 to 1999 in hokkaido, japan.	an epizootiological survey with histopathological methods was conducted for porcine circovirus in 220 diseased pigs (1-200 days old) in 49 farms from 1985 to 1999. histopathological lesions containing pcv antigen were detected mainly in the lymphoid tissues from 42 of 189 diseased pigs (22.2%) in 4 of 45 farms (8.9%) from 1990 to 1999. the rate of positive pigs gradually increased from 1997 onward and pcv infection was found in 50% of diseased pigs in 1999. histopathologically, the lesions in th ...	2000	10907690
severe leukopenia and liver necrosis in young african grey parrots (psittacus erithacus erithacus) infected with psittacine circovirus.	this paper describes the signs, clinical pathology, and postmortem findings in 14 young african grey parrots (psittacus erithacus erithacus) that were naturally infected with psittacine beak and feather disease (pbfd) virus (psittacine circovirus). all but two of the parrots had severe leukopenia at clinical presentation. two other parrots also had severe anemia. all birds died within 3 wk after presentation. postmortem examination documented liver necrosis in 11 of 14 birds and secondary bacter ...	2000	10879931
characterization of immune response of young pigs to porcine circovirus type 2 infection.	a longitudinal study was conducted to characterize the immune response of young swine to infection with porcine circovirus type 2 (pcv-2). five 8-week-old cesarean-derived, colostrum-deprived pigs were inoculated intranasally and intramuscularly with a field isolate of pcv-2 at a concentration of 10(4) tcid50/ml. along with monitoring for clinical signs and viremia, serum samples were collected from all pigs at day 0 and thereafter every 7 days postinoculation (pi) until the termination of the s ...	2000	10892995
distribution of porcine parvovirus in porcine circovirus 2-infected pigs with postweaning multisystemic wasting syndrome as shown by in-situ hybridization.	in-situ hybridization with a nonradioactive digoxigenin-labelled probe was used to study the distribution of porcine parvovirus (ppv) in formalin-fixed paraffin wax-embedded tissues from 10 porcine circovirus 2 (pcv2)-infected weaned pigs with naturally occurring postweaning multisystemic wasting syndrome (pmws). a 226 base pair dna fragment from a vp2 structural gene was generated by polymerase chain reaction (pcr) and used as a probe. lymph node, spleen, thymus and tonsil were positive by pcr, ...	2000	11042001
serum antibodies to porcine circovirus type 1 and type 2 in pigs with and without pmws.		2000	10909911
open reading frame 2 of porcine circovirus type 2 encodes a major capsid protein.	porcine circovirus 2 (pcv2), a single-stranded dna virus associated with post-weaning multisystemic wasting syndrome of swine, has two potential open reading frames, orf1 and orf2, greater than 600 nucleotides in length. orf1 is predicted to encode a replication-associated protein (rep) essential for replication of viral dna, while orf2 contains a conserved basic amino acid sequence at the n terminus resembling that of the major structural protein of chicken anaemia virus. thus far, the structur ...	2000	10950986
isolation and characterization of porcine circovirus type 2 from pigs showing signs of post-weaning multisystemic wasting syndrome in the netherlands.	pigs with wasting syndrome were examined for macroscopic and histopathological lesions, and for porcine circovirus (pcv). histopathological lesions were comparable to those previously documented for post-weaning multisystemic wasting syndrome (pmws). in addition, in seven out of ten examined pmws-affected pigs focal-to-slight mononuclear meningitis and focal cerebral mononuclear infiltrates (4 out of 10) were observed. a virus was isolated from organs and sera from pigs showing wasting syndrome. ...	2000	10952449
quantitative, competitive pcr analysis of porcine circovirus dna in serum from pigs with postweaning multisystemic wasting syndrome.	a competitive pcr (cpcr) assay was developed for monitoring porcine circovirus (pcv) dna in serum samples from piglets. the cpcr was based on competitive coamplification of a 502- or 506-bp region of the pcv type 1 (pcv1) or pcv2 orf2, respectively, with a known concentration of competitor dna, which produced a 761- or 765-bp fragment, respectively. the cpcr was validated by quantification of a known amount of pcv wild-type plasmids. we also used this technique to determine pcv genome copy numbe ...	2000	10970408
the sensitivities of various erythrocytes in a haemagglutination assay for the detection of psittacine beak and feather disease virus.	the erythrocytes of various species were tested in psittacine beak and feather disease (pbfd) virus haemagglutination (ha) and haemagglutination inhibition assays to determine which are suitable for use in these assays. ha activity was observed for erythrocytes of the salmon-crested cockatoo, the sulphur-crested cockatoo, the umbrella cockatoo, the goffin's cockatoo and the cockatiel, with differences amongst individuals within species, but not for erythrocytes of humans, the pig, the guinea pig ...	2000	11014065
development and application of a competitive enzyme-linked immunosorbent assay for the detection of serum antibodies to porcine circovirus type 2.	we report the development of a competitive enzyme-linked immunosorbent assay (c-elisa) for the detection of antibodies to porcine circovirus type 2 (pcv2), the agent associated with the recently described postweaning multisystemic wasting syndrome in pigs. at present, no method has been published describing a c-elisa for the detection of antibodies to pcv2, and currently employed tests are impractical for use in some laboratories. the assay described here uses a cell culture isolate of porcine c ...	2000	11021425
increase in pdns diagnoses in the netherlands.		2000	11037736
xenotransplantation and the potential risk of xenogeneic transmission of porcine viruses.	the clinical success of allotransplantation and the shortage of donor organs have led to a proposal for the use of animal organs as alternative therapeutic materials for humans. in that regard, swine are preferable to non-human primates as a source of donor organs. while applications for clinical trials for xenotransplantation have not yet been received in canada, several trials have already been authorized in the united states. a major concern, however, is the potential for xenogeneic transmiss ...	2000	11041495
seroprevalence of porcine circovirus types 1 and 2 in the belgian pig population.		2000	11087137
retrospective study of porcine circovirus 2 infection in japan: seven cases in 1989.	retrospectively, we demonstrated that seven pigs necropsied in 1989 had characteristic porcine circovirus 2 (pcv-2) lymphoid tissue lesions of severe lymphoid depletion, syncytial giant cell formation, and intracytoplasmic inclusion bodies in macrophages. immunohistochemically, pcv-2 antigen was detected in these tissues and the distribution of positive staining corresponded to the distribution of inclusion bodies. electron microscopy demonstrated viral particles compatible with porcine pcv-2. t ...	2000	11105959
analysis of seroconversion to porcine circovirus 2 among veterinarians from the united states and canada.		2000	11110452
porcine circovirus induces b lymphocyte depletion in pigs with wasting disease syndrome.	to disclose the mechanism of cellular injury following porcine circovirus (pcv) infection, 12 pigs were examined by the terminal deoxynucleotidyl transferase-mediated dutp-nick end labeling (tunel) method and immunohistochemistry. histologically, the lymphoid tissues were characterized by marked apoptosis of lymphocytes, lymphocyte depletion, and macrophages and giant cells containing numerous inclusion bodies with or without apoptotic bodies. immunohistochemically, there were many lysozyme-posi ...	2000	11129853
pcr detection and evidence of shedding of porcine circovirus type 2 in boar semen.	an experimental study was conducted to evaluate the potential presence of porcine circovirus type 2 (pcv2) in the semen of infected boars. four mature boars were inoculated intranasally with pcv2 isolate lhva-v53 propagated on pk15 cells. two boars inoculated with the supernatant of noninfected pk15 cells were kept as controls. serum samples were collected from all boars at 4, 7, 11, 13, 18, 21, 25, 28, 35, and 55 days postinoculation (dpi) and from the four pcv2-infected boars at 90 dpi. sample ...	2000	11101608
experimental transmission of porcine circovirus type 2 (pcv2) in weaned pigs: a sequential study.	weaned specific pathogen-free pigs were inoculated intranasally with porcine circovirus type 2 (pcv2) and killed in groups of two or three animals at 6, 13, 20, 27 and 34 days post-inoculation (dpi), together with appropriate uninfected controls, for examination by histopathological, immunohistochemical (immunogold silver staining; igss), polymerase chain reaction (pcr) and viral isolation techniques. serum samples were also collected for detection of antibodies. no major clinical signs were obs ...	2000	11041995
hepatitis and staging of hepatic damage in pigs naturally infected with porcine circovirus type 2.	a total of 100 liver samples from pigs with postweaning multisystemic wasting syndrome (pmws) were studied. all livers were evaluated microscopically and were staged based on the severity and localization of lesions. presence of porcine circovirus type 2 (pcv-2) was evaluated using an in situ hybridization technique. eighty-eight of 100 livers (88%) had a variable degree of lymphohistiocytic hepatitis, with apoptotic bodies, disorganization of hepatic plates, and/or perilobular fibrosis. twelve ...	2000	11105965
retrospective serological survey of antibodies to porcine circovirus type 1 and type 2.	a retrospective serological survey was performed to determine the presence of antibodies to porcine circovirus type 1 (pcv1) and porcine circovirus type 2 (pcv2) in serum samples collected from sows at slaughterhouses in canada in 1985, 1989, and 1997. each serum sample was tested by indirect immunofluorescence on pcv-free pk15 cells, on pcv1-infected pk15 cells and on pcv2-infected pk15 cells. for the 3 years studied, sera positive to pcv1 and pcv2 were identified and the number of sera positiv ...	2000	10935885
cloning and sequencing of columbid circovirus (cocv), a new circovirus from pigeons.	the complete nucleotide sequence of columbid circovirus (cocv) isolated from pigeons is described. cocv was amplified using a consensus primer pcr approach directed against conserved sequences within the rep genes of vertebrate circoviruses. the genome of cocv is circular and 2037 nt in size. it displays 55% homology to the genome of psittacine beak and feather disease virus and is more distantly related (< 40% homology) to porcine circovirus type 1 and 2. two major open reading frames were iden ...	2000	11205099
experimental infection of colostrum deprived piglets with porcine circovirus 2 (pcv2) and porcine reproductive and respiratory syndrome virus (prrsv) potentiates pcv2 replication.	experimental infection of colostrum-deprived (cd) pigs with a combined inoculum of porcine circovirus 2 (pcv2) and porcine reproductive and respiratory syndrome virus (prrsv) potentiated the replication and distribution of pcv2 virus, when compared with pigs inoculated with pcv2 alone. the replication and distribution of prrsv in dually infected pigs was not enhanced, when compared to pigs inoculated with prrsv alone. the mechanisms involved in the potentiation of pcv2 replication in pcv2/prrsv ...	2000	11205128
immunostimulation, pcv-2 and pmws.		2000	10975340
a sequential study of experimental infection of pigs with porcine circovirus and porcine parvovirus: immunostaining of cryostat sections and virus isolation.	the sequential tissue distribution of virus was investigated using virus isolation and immunofluorescence tests in 1-day-old piglets inoculated with porcine circovirus 2 (pcv2) and/or porcine parvovirus (ppv). enlarged mesenteric lymph nodes were seen in the pig inoculated with pcv2 alone and killed at 26 days post-inoculation (pi). one of the pigs inoculated with pcv2 and ppv and killed at 21 days pi had an enlarged liver. the pig killed at 26 days pi in this group had enlarged liver, kidneys a ...	2000	10763376
reproduction of lesions of postweaning multisystemic wasting syndrome by infection of conventional pigs with porcine circovirus type 2 alone or in combination with porcine parvovirus.	post-weaning multisystemic wasting syndrome (pmws) has recently emerged as an important disease of pigs in north america, europe and asia. porcine circovirus type 2 (pcv2) and porcine parvovirus (ppv) have been isolated from affected pigs. to investigate the pathogenicity of these isolates, groups of colostrum-deprived conventional pigs were inoculated with pcv2 alone (n=4), ppv alone (n=3) or dually with pcv2 and ppv (n=7) and examined post mortem between 21 and 26 days post-infection (dpi). tw ...	2000	10627387
characterisation of pcv-2 isolates from spain, germany and france.	the new isolated circovirus variant pcv-2 is discussed to be the etiological agent of a new emerging swine disease with a variable morbidity and high lethality, postweaning multisystemic wasting syndrome (pmws). pmws has been diagnosed in north america and west europe. clinical signs include dyspnea, loss of weight, lymph node enlargement and lymphocyte depletion in lymphoid tissues. this report describes the characterisation of pcv-2 isolates from animals affected with pmws from germany, spain ...	2000	10653918
identification of porcine circovirus in tissues of pigs with porcine dermatitis and nephropathy syndrome.	thirty-three pigs affected by porcine dermatitis and nephropathy syndrome, 30 from spain and three from the usa, were investigated in order to detect porcine circovirus (pcv) in their tissues. a standard in situ hybridisation technique using a specific dna 317-bp probe based on a well-conserved sequence of pcv (which recognises both pcv-1 and pcv-2) was applied to formalin-fixed, paraffin-embedded tissues. twenty-eight of the 30 spanish pigs and all three american pigs had pcv in at least one ti ...	2000	10678809
pcr detection and characterization of type-2 porcine circovirus.	a polymerase chain reaction (pcr) assay was developed for detecting porcine circovirus (pcv). the assay readily detected type-2 pcv (pcv-2) and type-1 pcv (pcv-1). the pcr primers were designed based on dna sequences conserved in all reported pcv genomes. type 1 pcv and type 2 pcv both produced 438 bp amplification products, which were easily identified and differentiated from one another by restriction fragment length polymorphism (rflp) analysis. porcine circovirus was detected in 55% (931/169 ...	2000	10680656
prevalence of the newly described human circovirus, ttv, in united states blood donors.	a novel nonenveloped single-stranded circular dna virus (ttv) was recently identified. the prevalence of ttv in blood donors in the united states is, however, still unclear.	2000	10686010
porcine circoviruses: a review.	porcine circoviruses (pcv) are small nonenveloped dna viruses containing a unique single-stranded circular genome. previously, no recognized link was found between pcv infection of pigs and disease, and pcv was considered a nonpathogenic agent. over the last 5 years, a "novel" pcv, designated pcv2, has been associated with various disease syndromes in pigs, primarily postweaning multisystemic wasting syndrome (pmws). pigs with pmws have a variety of clinical signs, including debility, dyspnea, p ...	2000	10690769
coinfection by porcine circoviruses and porcine parvovirus in pigs with naturally acquired postweaning multisystemic wasting syndrome.	postweaning multisystemic wasting syndrome (pmws) is an emerging disease in swine. recently, the disease has been reproduced with inocula containing a newly described porcine circovirus (pcv), designated pcv 2, and porcine parvovirus (ppv). in order to determine if these viruses interact in naturally acquired pmws, affected tissues from field cases were examined by immunohistochemistry (ihc) and polymerase chain reaction (pcr) for pcv 2 and ppv, as well as by pcr for the other recognized porcine ...	2000	10690771
pmws and porcine dermatitis nephropathy syndrome in great britain.		2000	10706335
prevalence of tt virus infection in blood donors with elevated alt in the absence of known hepatitis markers.	recently a novel dna virus (tt virus) has been identified in japan and shown to be associated with elevated aminotransferase levels after blood transfusion. the exact role of ttv in the pathogenesis of liver disease is yet to be established. our aim was to determine the prevalence and role of ttv in the pathogenesis of elevated transaminases in healthy blood donors in the absence of markers for viral hepatitis a-c.	2000	10710073
porcine postweaning multisystemic wasting syndrome in korean pig: detection of porcine circovirus 2 infection by immunohistochemistry and polymerase chain reaction.	this report describes the first diagnosis of porcine circovirus (pcv) infection in weaned pigs with postweaning multisystemic wasting syndrome in korea by immunohistochemistry and polymerase chain reaction. the most unique lesions were multifocal granulomatous inflammation affecting lymph nodes, liver, and spleen, characterized by infiltrates of epithelioid macrophages and multinucleated giant cells. circoviral antigen was detected in formalin-fixed sections and was usually present in large, rou ...	2000	10730945
high frequency of postnatal transmission of tt virus in infancy.	dna of tt virus (ttv), a novel human circovirus, was tested for in 116 mother-infant pairs who had participated in the adult t-cell leukemia prevention program (app) in nagasaki, japan, and refrained from breast-feeding. by polymerase chain reaction with okamoto's seminested primers, 36 of the 115 (31%) mothers were positive. at the age of 6-8 months, 7 of 29 (24%) and 6 of 72 (8%) infants born to infected and uninfected mothers were positive, respectively (p = 0.047; rr, 2.90). maternal ttv dna ...	2000	10795520
viral wasting syndrome of swine: experimental reproduction of postweaning multisystemic wasting syndrome in gnotobiotic swine by coinfection with porcine circovirus 2 and porcine parvovirus.	one-day-old gnotobiotic piglets were inoculated intranasally with in vitro passaged porcine circovirus 1 (pcv-1), pcv-2, and porcine parvovirus (ppv) alone or in combination (pcv-1/pcv-2, pcv-1/ppv, and pcv-2/ppv). piglets were evaluated for 1) the development of porcine postweaning multisystemic wasting syndrome (pmws), 2) distribution of viral antigens by immunochemistry, and 3) viremia and the presence of viral dna in nasal and ocular secretions and feces. all single agent-infected piglets an ...	2000	10810990
pcv-2-associated pdns in northern ireland in 1990. porcine dermatitis and nephropathy syndrome.		2000	10887989
porcine circovirosis in spain.		2000	10839241
differential recognition of orf2 protein from type 1 and type 2 porcine circoviruses and identification of immunorelevant epitopes.	two types of porcine circovirus (pcv) have been isolated and are referred to as pcv1 and pcv2. pcv1 represents an apathogenic virus, whereas pcv2 is associated with post-weaning multisystemic wasting syndrome. the two pcvs are related, since they display about 70% identity based on nucleotide sequences. in order to discriminate between common and type-specific antigens, an immunocytological approach was used following transfections with cloned circovirus dnas, as well as recombinant proteins exp ...	2000	10859388
development of probes to differentiate porcine circovirus types 1 and 2 in vitro by in situ hybridization.	porcine circovirus type 1 (pcv1), a pk-15 cell line contaminant, and porcine circovirus type 2 (pcv2), associated with post-weaning multisystemic wasting syndrome (pmws), are genetically and antigenically related. several techniques have been developed to detect pcv, including in situ hybridization (ish). previously reported probes used for ish may hybridize with both pcv1 and pcv2 nucleic acids. we attempted to produce probes for ish that can detect and differentiate pcv2 from pcv1 in pcv-infec ...	2000	10865154
pdns, pmws and porcine circovirus type 2 in scotland. porcine dermatitis and nephropathy syndrome. post-weaning multisystemic wasting syndrome.		2000	10872790
genetic characterization of type 2 porcine circovirus (pcv-2) from pigs with postweaning multisystemic wasting syndrome in different geographic regions of north america and development of a differential pcr-restriction fragment length polymorphism assay to detect and differentiate between infections with pcv-1 and pcv-2.	postweaning multisystemic wasting syndrome (pmws) is an emerging disease in swine. increasing evidence indicates that a variant strain of porcine circovirus (pcv), designated type 2 pcv (pcv-2), is responsible for pmws. to determine the extent of genetic heterogeneity of pcv-2 isolates, the complete genomes of six pcv-2 isolates from different regions of north america were amplified by pcr and sequenced. sequence and phylogenetic analyses confirmed that two distinct genotypes of pcv exist: nonpa ...	2000	10878032
atrophy of the primary lymphoid organs of meat pigeons in italy associated with circoviruslike particles in the bursa of fabricius.	during a survey effected in a meat pigeon slaughterhouse of central italy, atrophy of primary lymphoid organs (bursa of fabricius and thymus) and hypoplasia of bone marrow were observed. histologic, ultrastructural, and hematologic examinations were performed on a total of 80 randomly selected 30-day-old meat pigeons. by histologic studies, lymphocytic depletion and necrosis with cyst formations in the bursa of fabricius were detected in all subjects that showed thymus and bursa atrophy at necro ...	2000	10879928
absence of evidence for porcine circovirus type 2 in cattle and humans, and lack of seroconversion or lesions in experimentally infected sheep.	no antibodies to porcine circovirus type 2 were detected in sera from cattle, sheep and humans. experimental infection of lambs with this virus failed to produce lesions or seroconversion.	2000	10893163
electron microscopical observations of psittacine beak and feather disease in an umbrella cockatoo (cacatua alba).	psittacine beak and feather disease (pbfd) was diagnosed in an umbrella cockatoo (cacatua alba) with severe feather dystrophy and loss. electron microscopically, the intranuclear and intracytoplasmic inclusion bodies observed by light microscopy were composed of viral particles forming paracrystalline arrays, whorls, semicircles or concentric circles. recovered viral particles from the skin and feather follicle tracts were icosahedral and 15 to 20 nm in diameter.	1999	10535515
evidence that a plant virus switched hosts to infect a vertebrate and then recombined with a vertebrate-infecting virus.	there are several similarities between the small, circular, single-stranded-dna genomes of circoviruses that infect vertebrates and the nanoviruses that infect plants. we analyzed circovirus and nanovirus replication initiator protein (rep) sequences and confirmed that an n-terminal region in circovirus reps is similar to an equivalent region in nanovirus reps. however, we found that the remaining c-terminal region is related to an rna-binding protein (protein 2c), encoded by picorna-like viruse ...	1999	10393941
typing of porcine circovirus in clinical specimens by multiplex pcr.	a multiplex pcr assay was developed to detect and differentiate between the porcine circovirus (pcv) infecting persistently the pk 15 cell line (pcv type i) and the pcv associated with postweaning multisystemic wasting syndrome (pmws) (pcv type ii). dna products with unique sizes characteristic of each type of pcv were obtained. sequencing of these products demonstrated that the nucleotide sequences were type-specific. tissue samples from a total of 42 field cases from québec were studied, among ...	1999	10403678
experimental inoculation of conventional pigs with tissue homogenates from pigs with post-weaning multisystemic wasting syndrome.	this report describes the experimental inoculation of conventional pigs with a tissue homogenate obtained from two pigs affected with postweaning multisystemic wasting syndrome (pmws). eight 2-month-old pigs were inoculated by the intranasal route, and two pigs were left as uninfected controls. clinical signs, rectal temperatures and body weights were recorded. pigs were necropsied at days 14 or 21 post-inoculation, and tissue samples were taken for histopathology and porcine circovirus (pcv) in ...	1999	10405306
post-weaning multisystemic wasting syndrome in spain.		1999	10460036
identification and incidence of porcine circovirus in routine field cases in québec as determined by pcr.		1999	10466832
a comparison of in situ hybridization and immunohistochemistry for the detection of a new porcine circovirus in formalin-fixed tissues from pigs with post-weaning multisystemic wasting syndrome (pmws).	post-weaning multisystemic wasting syndrome (pmws) is a recently identified condition affecting pigs in north america and europe. porcine circovirus antigen and nucleic acid have been demonstrated associated with lesions, and a new porcine circovirus designated pcv2 has been recovered from tissues of these animals. in this study, in situ hybridisation and immunohistochemical protocols were developed, optimized and compared for their relative sensitivity in detecting pcv2 antigens and nucleic aci ...	1999	10471021
in-situ hybridization for the detection of porcine circovirus in pigs with postweaning multisystemic wasting syndrome.	in-situ hybridization with a non-radioactive digoxigenin-labelled probe was used to detect porcine circovirus (pcv) in formalin-fixed paraffin wax-embedded tissues from 10 weaned pigs with naturally occurring postweaning multisystemic wasting syndrome (pmws). a 530 base pair dna fragment from an open reading frame 1 was generated by the polymerase chain reaction. by in-situ hybridization, a distinct positive signal was detected in all 10 pigs. the morphology of host cells was preserved despite t ...	1999	10486162
[possible pathogen: porcine circovirus (pcv)].		1999	10486869
ultrastructure of porcine circovirus in persistently infected pk-15 cells.	the ultrastructure of porcine circovirus was examined in persistently infected porcine kidney (pk)-15 cells. virus-infected pk-15 cells had large numbers of intracytoplasmic inclusions, and a few cells had intranuclear inclusions. intracytoplasmic inclusions were dispersed throughout the cytoplasm but were most numerous in the perinuclear cytoplasm. inclusion were of various sizes, round to oval, and electron dense and were of two general types. inclusions of the first type were small (0.1-0.5 m ...	1999	10490204
observations on pigeon circovirus infection in ontario.	subclinical pigeon circovirus infection was diagnosed in 1-day-old to 6-week-old birds from a loft with no history of clinical disease. pigeons from other lofts presented with various illnesses and were found at necropsy to be concurrently infected with pigeon circovirus.	1999	10495910
detection of porcine circovirus from lesions of a pig with wasting disease in japan.	a wasting disease characterized by progressive weight loss and dyspnea has been observed in weaning pigs on a farm in yamagata prefecture in 1998. histopathologic findings in an affected pig were bronchointerstitial pneumonia and intracytoplasmic clusters of basophilic inclusions in macrophages of lymph nodes, which were similar to those in pigs with postweaning multisystemic wasting syndrome (pmws) recently reported in north america and europe. porcine circovirus (pcv)-like particles were obser ...	1999	10563289
multiplex pcr for detection and typing of porcine circoviruses.	sets of oligonucleotide primers were designed according to the sequences of the open reading frames (orfs) orf1 and orf2 of the prototype nonpathogenic pk-15 strain of porcine circovirus (pcv) type 1 (pcv-1). by the pcr performed with the various primer sets, genomic dna or rna from other bacterial or viral pathogens of the respiratory tracts of pigs could not be amplified. a positive amplification reaction could be visualized with dna extracted from a viral suspension containing as few as 10 vi ...	1999	10565907
persistent infection with chicken anaemia virus and some effects of highly virulent infectious bursal disease virus infection on its persistency.	chicken anaemia virus (cav) infectivity and the effect of highly virulent infectious bursal disease virus (hv ibdv) infection on cav's infectivity were examined in chickens inoculated with cav or inoculated dually with cav and hv ibdv. five chickens inoculated dually with hv ibdv at 35 days old and then with cav at 40 days old exhibited no clinical signs of disease, but showed atrophic bursae of fabricius when necropsied 4 weeks later. upon examining the chickens at 7 days postinoculation (dpi) ...	1999	10607503
a universal polymerase chain reaction for the detection of psittacine beak and feather disease virus.	a universal pcr assay was designed that consistently detected psittacine beak and feather disease virus (bfdv) in psittacine birds affected with psittacine beak and feather disease (pbfd) from different geographic regions across australia. primers within open reading frame 1 (orf1) of the bfdv genome consistently amplified a 717 bp product from blood and/or feathers of 32 birds with pbfd lesions. the pcr did not amplify a product from the feathers or blood from 7 clinically normal psittacine bir ...	1999	10501171