| antigen selection and presentation to protect against transmissible gastroenteritis coronavirus. | the antigenic structure of the s glycoprotein of transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) has been determined and correlated with the physical structure. four antigenic sites have been defined (a, b, c, and d). the sites involved in the neutralization of tgev are: a, d, and b, sites a and d being antigenically dominant for tgev neutralization in vitro. these two sites have specific properties of interest: site a is highly conserved and is present in c ... | 1992 | 1282756 |
| porcine respiratory coronavirus isolated from young piglets in quebec. | | 1992 | 1322580 |
| sequence analysis of the leader rna of two porcine coronaviruses: transmissible gastroenteritis virus and porcine respiratory coronavirus. | the leader rna sequence was determined for two pig coronaviruses, transmissible gastroenteritis virus (tgev), and porcine respiratory coronavirus (prcv). primer extension, of a synthetic oligonucleotide complementary to the 5' end of the nucleoprotein gene of tgev was used to produce a single-stranded dna copy of the leader rna from the nucleoprotein mrna species from tgev and prcv, the sequences of which were determined by maxam and gilbert cleavage. northern blot analysis, using a synthetic ol ... | 1990 | 1962975 |
| experimental infection of pigs with the porcine respiratory coronavirus (prcv): measure of viral excretion. | twelve pigs were experimentally infected with a porcine respiratory coronavirus (prcv) by the oronasal route. viral excretion was measured daily by two means-deep nasal swabs and air samples obtained in a cyclone sampler. clinical signs were very slight on infected pigs. airborne virus could be recovered from day 1 to day 6 post-infection in the cyclone sampler as well as in petri dishes placed in the same loose-box. viral titres obtained from nasal swabs were significantly correlated with those ... | 1992 | 1319623 |
| a competitive inhibition elisa for the differentiation of serum antibodies from pigs infected with transmissible gastroenteritis virus (tgev) or with the tgev-related porcine respiratory coronavirus. | a competitive inhibition elisa was developed to detect non-neutralizing antibodies to the peplomer protein of transmissible gastroenteritis virus (tgev) in porcine sera using a monoclonal antibody as an indicator. it was demonstrated that field strains of the tgev-related porcine respiratory coronavirus (prcv) did not induce this antibody, whereas the miller strain and field strains of tgev did. the sensitivity of the competitive inhibition elisa appeared to be similar to that of the virus neutr ... | 1989 | 2548322 |
| comparison of the antibody response to transmissible gastroenteritis virus and porcine respiratory coronavirus, using monoclonal antibodies to antigenic sites a and x of the s glycoprotein. | pigs were inoculated with various strains of transmissible gastroenteritis virus (tgev) or with porcine respiratory coronavirus (prcv), and antigenic site-specific antibody responses were compared. a blocking-elisa was used to study to what extent antibodies in convalescent sera interfered with the binding of monoclonal antibodies (mab) 57.16 or 57.110 to the attenuated tgev/purdue virus. monoclonal antibody 57.16 is directed against the a site on the peplomer, neutralizes virus, and recognizes ... | 1992 | 1315491 |
| [the prevalence of antibodies to influenza virus and respiratory coronavirus in fattening pigs in spain]. | the presence of antibodies to two influenza viruses of the type a (h1n1 and h3n2) and to a porcine respiratory coronavirus was investigated in a study lasting a year. 735 blood serum samples were collected from 79 closed pig fattening farms in the province segovia (spain). hemagglutination inhibition was used with influenza viruses. the percentage of positive results was 78.5% and 62.5% respectively for the serotypes h1n1 and h3n2. a clear reduction in the spread of antibodies was observed in th ... | 1989 | 2554624 |
| porcine respiratory coronavirus differs from transmissible gastroenteritis virus by a few genomic deletions. | the genome organization of porcine respiratory coronavirus (prcv), a newly recognized agent which has a close antigenic relationship to the enteropathogenic transmissible gastroenteritis virus (tgev), was studied. genomic rna from cell-cultured prcv (french isolate rm4) was used to produce cdna clones covering the genomic 3' end to the start of the spike (s) glycoprotein gene (7519 nucleotides). six open reading frames (orfs) were identified that allowed the translation of three coronavirus stru ... | 1990 | 2174956 |
| intestinal replication of a porcine respiratory coronavirus closely related antigenically to the enteric transmissible gastroenteritis virus. | one-week-old piglets were inoculated with the porcine respiratory coronavirus (prcv) either intravenously or directly into the lumen of the gastrointestinal tract. both inoculation routes resulted in the isolation of virus from the caudal small intestine. viral replication, however, was only observed upon inoculation into the digestive tract in quantities of greater than or equal to 10(3) tcid50. replication remained limited to a few unidentified cells located in or underneath the epithelial lay ... | 1990 | 2169676 |
| sows infected in pregnancy with porcine respiratory coronavirus show no evidence of protecting their sucking piglets against transmissible gastroenteritis. | eighteen litters of sucking piglets were challenged with one of two strains of transmissible gastroenteritis virus (tgev). during pregnancy, their seronegative dams had been either inoculated intranasally with porcine respiratory coronavirus (prcv), inoculated orally with tgev or left untreated. on the basis of weight gain, clinical signs and survival, no differences in response to challenge was detected when piglets suckled by prcv inoculated sows were compared with those suckled by uninoculate ... | 1990 | 2168106 |
| titration of two porcine respiratory viruses in mammalian cell cultures by direct fluorescent antibody staining. | | 1974 | 4591612 |
| disorders induced by the experimental infection of pigs with the porcine respiratory coronavirus (p.r.c.v.). | five colostrum deprived hysterectomy-derived piglets were inoculated by the intratracheal route with a porcine respiratory coronavirus (prcv). the clinical effects and growth performances were compared with those in 5 similar piglets which were inoculated with minimum eagle medium only. a transient hyperthermia, mild to severe dyspnoea, polypnoea and an obvious cessation of growth were recorded on infected pigs only whereas the control group did not show any adverse reaction after inoculation. t ... | 1990 | 2166983 |
| sites of replication of a porcine respiratory coronavirus related to transmissible gastroenteritis virus. | a porcine respiratory coronavirus (prcv) was inoculated by aerosol into nine hysterectomy-derived and colostrum-deprived pigs at the age of one week. they were killed at different times after inoculation and tissues were sampled for virus isolation and immunofluorescence. results indicate that virus replicated to high titres in the respiratory tract. replication mainly occurred in alveolar cells but also in epithelial cells of nasal mucosa, trachea, bronchi, bronchioli, in alveolar macrophages a ... | 1990 | 2159175 |
| molecular aspects of the relationship of transmissible gastroenteritis virus (tgev) with porcine respiratory coronavirus (prcv). | | 1990 | 1966436 |
| infection with a new porcine respiratory coronavirus in denmark: serologic differentiation from transmissible gastroenteritis virus using monoclonal antibodies. | in 1984 neutralizing antibodies against transmissible gastroenteritis virus (tgev) were detected in pig herds in a small geographical area in the southern part of denmark. no clinical symptoms were observed and accumulating epidemiological evidence gradually pointed towards a respiratory infection. in 1986 a tge-like virus, tentatively named porcine respiratory coronavirus (prcv), was isolated from the lungs of swine. the virus was partially characterized using monoclonal antibodies against tgev ... | 1990 | 1966435 |
| sites of replication of a porcine respiratory coronavirus in 5-week-old pigs with or without maternal antibodies. | on farms, where the porcine respiratory coronavirus (prcv) is enzootic, pigs usually become infected between 5 and 10 weeks of age while losing their maternal antibodies. it was examined whether prcv replicates in the small intestine in such pigs. this point is important since intestinal replication with prcv might induce immunity against tgev not only by stimulating mucosal intestinal immunity, but also by the induction of a lactogenic iga response at later age via the gut-mammary link. five we ... | 1990 | 1966434 |
| induction of milk iga antibodies by porcine respiratory coronavirus infection. | an elisa was developed to examine the prevalence of tgev-specific immunoglobulin (ig)a in the milk of sows, infected in the field with prcv or with tgev. it was shown that previous prcv-infections can induce the secretion of iga antibodies in the milk. however, only 9 out of 28 prcv-infected sows had iga in their milk whereas 11 tgev-infected sows all secreted iga. on farms where a reinfection with prcv occurred, the number of iga-secreting sows increased from 2 to 11 on a total of 13 sows. this ... | 1990 | 1966433 |
| background paper. the appearance of the porcine respiratory coronavirus has created new problems and perspectives. | | 1990 | 1966432 |
| further characterization of aminopeptidase-n as a receptor for coronaviruses. | we recently reported that porcine aminopeptidase-n (papn) acts as a receptor for transmissible gastroenteritis virus (tgev). in the present work, we addressed the question of whether tgev tropism is determined only by the virus-receptor interaction. to this end, different non-permissive cell lines were transfected with the porcine apn cdna and tested for their susceptibility to tgev infection. the four transfected cell lines shown to express papn at their membrane became sensitive to infection. ... | 1993 | 7911642 |
| three new isolates of porcine respiratory coronavirus with various pathogenicities and spike (s) gene deletions. | three new isolates of porcine respiratory coronavirus (prcv) were isolated and partially characterized. these prcv isolates showed a selective tropism for respiratory tissue and were antigenically related to transmissible gastroenteritis virus. pcr amplification of the 5' half of the spike (s) genes of the three prcv isolates indicated that a large deletion, characteristic of prcv, was present. by using cdna probes specific for the transmissible gastroenteritis virus s gene, the pcr products wer ... | 1994 | 7929779 |
| evidence for a porcine respiratory coronavirus, antigenically similar to transmissible gastroenteritis virus, in the united states. | a respiratory variant of transmissible gastroenteritis virus (tgev), designated prcv-ind/89, was isolated from a swine breeding stock herd in indiana. the virus was readily isolated from nasal swabs of pigs of different ages and induced cytopathology on primary porcine kidney cells and and on a swine testicular (st) cell line. an 8-week-old pig infected oral/nasally with the respiratory variant and a contact pig showed no signs of respiratory or enteric disease. these pigs did not shed virus in ... | 1990 | 1965638 |
| genetic analysis of porcine respiratory coronavirus, an attenuated variant of transmissible gastroenteritis virus. | the genome and transcriptional pattern of a newly identified respiratory variant of transmissible gastroenteritis virus were analyzed and compared with those of classical enterotropic transmissible gastroenteritis virus. the transcriptional patterns of the two viruses indicated that differences occurred in rnas 1 and 2(s) and that rna 3 was absent in the porcine respiratory coronavirus (prcv) variant. the smaller rna 2(s) of prcv was due to a 681-nucleotide (nt) deletion after base 62 of the prc ... | 1991 | 1851885 |
| sequence comparison of the 5' end of mrna 3 from transmissible gastroenteritis virus and porcine respiratory coronavirus. | analysis of porcine transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) mrna species indicated a deletion in mrna 3 of prcv. polymerase chain reaction (pcr) was used to clone the 5' end of mrna 3 from prcv for comparison with the equivalent region in tgev. small deletions were observed within and around the prcv sequence equivalent to the putative open reading frame (orf) orf-3a identified in tgev. the potential rna polymerase-leader complex binding site (leader ... | 1991 | 1848593 |
| differentiation of transmissible gastroenteritis virus from porcine respiratory coronavirus and other antigenically related coronaviruses by using cdna probes specific for the 5' region of the s glycoprotein gene. | two cdna clones prepared from the virulent miller strain of transmissible gastroenteritis virus (tgev) were identified, and their nucleotide sequences were determined. the clones were nonoverlapping and located in the 5' region of the s glycoprotein gene. their nucleotide and predicted amino acid sequences were compared with published sequences of the attenuated purdue strain of tgev and feline infectious peritonitis virus (fipv). tgev clone pe21 contained 381 bp of the s glycoprotein gene and h ... | 1991 | 1847152 |
| an elisa for the detection of serum antibodies to both transmissible gastroenteritis virus and porcine respiratory coronavirus. | a competition elisa utilizing a mab directed towards a peplomer protein epitope common to tgev, prcv and related feline and canine coronaviruses is described. | 1991 | 1717102 |
| the cloning and sequencing of the virion protein genes from a british isolate of porcine respiratory coronavirus: comparison with transmissible gastroenteritis virus genes. | previous analysis of porcine respiratory coronavirus (prcv) mrna species showed that mrnas 2 and 3 were smaller than the corresponding transmissible gastroenteritis virus (tgev) mrna species (page et al. (1991) j. gen. virol. 72, 579-587). sequence analysis showed that mrna 3 was smaller due to the presence of a new putative rna-leader binding site upstream of the prcv orf-3 gene. however, this observation did not explain the deletion observed in prcv mrna 2. polymerase chain reaction (pcr) was ... | 1991 | 1662846 |
| serological studies of transmissible gastroenteritis in great britain, using a competitive elisa. | a competitive elisa which differentiates between transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) was used to detect non-neutralising antibodies to the peplomer protein of tgev in porcine sera. the test was shown to be tgev specific, having a relative specificity of 100 per cent, and to have a relative sensitivity of 94.9 per cent when compared with the virus neutralisation test. the prevalence of tgev in great britain is low; only 0.6 per cent of sows sample ... | 1991 | 1651028 |
| differentiation between transmissible gastroenteritis virus and porcine respiratory coronavirus using a cdna probe. | a plasmid, pg3bs, containing a cdna clone from the 5' coding region of the peplomer glycoprotein gene appears to be specific for enteric transmissible gastroenteritis virus (tgev) strains and for live-attenuated tgev vaccines. this cdna probe is used to differentiate porcine respiratory coronavirus (prcv) isolates from tgev field and vaccine strains by a slot blot hybridization assay. probe pg3bs also hybridizes to canine coronavirus (ccv) rna but does not hybridize to antigenically related feli ... | 1991 | 1645595 |
| analysis of a 9.6 kb sequence from the 3' end of canine coronavirus genomic rna. | we have analysed the organization of the 3' end of the genomic rna of canine coronavirus (ccv), a virus which has a close antigenic relationship to transmissible gastroenteritis virus (tgev), porcine respiratory coronavirus (prcv) and feline infectious peritonitis virus (fipv). genomic rna isolated from ccv strain insavc-1-infected a72 cells was used to generate a cdna library. overlapping clones, spanning approximately 9.6 kb [from the 3' end of the polymerase gene, 1b, to the poly(a) tail] wer ... | 1992 | 1431811 |
| epitope specificity of protective lactogenic immunity against swine transmissible gastroenteritis virus. | the epitope specificity of the protective immune response against swine transmissible gastroenteritis (tge) has been investigated by using circulating and secretory antibodies. this study was carried out with sows vaccinated with tgev or the antigenically related porcine respiratory coronavirus (prcv). tgev vaccination of sows resulted in greater lactogenic protection of suckling piglets against tgev challenge and a higher secretory immune response than prcv vaccination did. these differences in ... | 1992 | 1383566 |
| antigenic variation among transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus strains detected with monoclonal antibodies to the s protein of tgev. | five nonneutralizing monoclonal antibodies (mab) generated to the virulent miller strain of transmissible gastroenteritis virus (tgev) and specific for the s protein were characterized. competition assays between purified and biotinylated mab indicated that mab 75b10 and 8g11 mapped near a new subsite, designated v and 2 mab, 44c11 and 45a8, mapped to a previously designated subsite d. a fifth mab mapped between subsites v and e. these mab were tested with 3 previously characterized mab to subsi ... | 1992 | 1379786 |
| pathogenicity of concurrent infection of pigs with porcine respiratory coronavirus and swine influenza virus. | combinations of porcine respiratory coronavirus (prcv) and either of two swine influenza viruses (h1n1 or h3n2) were administered intranasally and by aerosol to six- to eight-week-old specific pathogen-free pigs. the clinical responses, gross respiratory lesions and growth performances of these pigs were studied and compared with those of single (prcv, h1n1 or h3n2) and mock-infected animals. prcv infection caused fever, growth retardation and lung lesions, but no respiratory symptoms. infection ... | 1992 | 1334565 |
| sero-epidemiological survey of porcine respiratory coronavirus (prcv) infection in breeding herds in southeastern spain. | in 1987 we conducted a sero-epidemiological survey in the murcia region (south-east spain) to discover the prevalence and spread of prcv-infection among breeding pigs and farms and determine the association between herd size and geographical zone with prcv-infection. the murcia region was divided into four geographical zones and the farms classified by size in four categories. the random sample was statistically representative of both the breeding stock and farms in each geographical zone. we an ... | 1992 | 1325719 |
| infection with porcine respiratory coronavirus does not fully protect pigs against intestinal transmissible gastroenteritis virus. | eight nine-week-old specific-pathogen-free pigs which had been infected with the transmissible gastroenteritis virus (tgev)-related porcine respiratory coronavirus (prcv) and four uninfected littermates were challenged with tgev. the previous prcv infection failed to protect them against the enteric tgev infection. virus excretion in faeces was detected by an elisa in all the pigs for three to six consecutive days after inoculation. although little diarrhoea was observed, the infection extended ... | 1989 | 2549676 |
| antigenic differentiation between transmissible gastroenteritis virus of swine and a related porcine respiratory coronavirus. | the antigenic relationship between a recently isolated porcine respiratory coronavirus (tlm 83) and transmissible gastroenteritis (tge) virus of swine was studied by neutralization, immunoblotting and radioimmunoassay (ria) using tge virus-specific monoclonal antibodies (mabs) and polyclonal antibodies specific for both viruses. a complete two-way neutralization activity between the two viruses was found. immunoblotting revealed cross-reactions between tlm 83 and tge virus antigens at the level ... | 1988 | 2839605 |
| isolation of a porcine respiratory, non-enteric coronavirus related to transmissible gastroenteritis. | a porcine respiratory, non-enteric virus which is related to the coronavirus transmissible gastroenteritis virus (tgev) has been isolated in pigs and in cell culture. the isolate was designated tlm 83. it has become very widespread and enzootic among the swine population in belgium and in other swine raising countries. it causes an infection of the lungs and appears to spread by aerogenic route. it does not replicate in the enteric tract. the experimental infection in conventional and gnotobioti ... | 1986 | 3018993 |
| characterization of the iga and subclass igg responses to neutralizing epitopes after infection of pregnant sows with the transmissible gastroenteritis virus or the antigenically related porcine respiratory coronavirus. | in this study, we have investigated the characteristics of secreted iga and other classes of ig induced after vaccination of sows with transmissible gastroenteritis virus (tgev) or the antigenically related porcine respiratory coronavirus (prcv). both viruses induced the secretion of neutralizing antibodies of different classes in the sows' milk, but these protected suckling piglets against tgev to different degrees. quantitative differences in the induction of iga by both viruses were found amo ... | 1994 | 7523577 |
| lactogenic immunity and milk antibody isotypes to transmissible gastroenteritis virus in sows exposed to porcine respiratory coronavirus during pregnancy. | passive protection provided by sows inoculated with the virulent miller strain of transmissible gastroenteritis virus (tgev), or the isu-1 strain of porcine respiratory coronavirus (prcv), or both was evaluated in nursing pigs challenge exposed with virulent tgev. four sows (group b) were inoculated with prcv oronasally twice at 4 and 2 weeks before parturition; 1 sow (group c) was inoculated similarly, but in 2 subsequent pregnancies; and 2 sows (group d) were oronasally primed with prcv at 4 w ... | 1995 | 7653882 |
| sequence comparison of porcine respiratory coronavirus isolates reveals heterogeneity in the s, 3, and 3-1 genes. | four new porcine respiratory coronavirus (prcv) isolates were genetically characterized. subgenomic mrna patterns and the nucleotide sequences of the 5' ends of the s genes, the open reading frame (orf) 3/3a genes, and the orf 3-1/3b genes of these prcv isolates were determined and compared with those of other prcv and transmissible gastroenteritis virus (tgev) isolates. the s, orf 3/3a, and orf 3-1/3b genes are under intense study because of their possible roles in determining tissue tropism an ... | 1995 | 7707547 |
| porcine respiratory coronavirus-mediated interference against influenza virus replication in the respiratory tract of feeder pigs. | effect of prior porcine respiratory coronavirus (prcv) infection on replication of h1n1-influenza virus in the respiratory tract of swine was studied. in an initial experiment, 3 groups of 5 feeder pigs were studied. pigs of 2 groups were inoculated sequentially with prcv, followed by h1n1-influenza virus at 2- and 3-day intervals. pigs of the other group were inoculated with h1n1-influenza virus only. pigs were monitored clinically and examined for nasal excretion of influenza virus. in the sin ... | 1994 | 7802396 |
| serological studies in austrian fattening pigs with respiratory disorders. | serum samples of 253 fattening pigs out of 44 different herds with respiratory signs were examined for antibodies to aujeszky's disease virus by elisa, swine influenza virus (hi test), porcine respiratory coronavirus (elisa) and porcine reproductive and respiratory syndrome virus (ipma). one single case of aujeszky's disease was detected at slaughter. on the other hand 24.5% of the animals proved to be positive for swine influenza, although no vaccine is licensed in austria, and 63.6% reacted po ... | 1994 | 7810433 |
| immunity to transmissible gastroenteritis virus and porcine respiratory coronavirus infections in swine. | despite the pioneering efforts to identify correlates of passive immunity to transmissible gastroenteritis virus (tgev), effective vaccines for the control of tge in suckling pigs have remained elusive. the initial concept of an enteromammary immunologic axis in monogastrics originated from studies of lactogenic immunity to tgev in swine. these studies revealed that infection of pregnant swine with virulent tgev stimulated high titers of siga antibodies in milk which correlated with protection o ... | 1994 | 7856068 |
| prevalence of infections with enzootic respiratory and enteric viruses in feeder pigs entering fattening herds. | the prevalence of infections with h1n1- and h3n2-influenza viruses, porcine respiratory coronavirus (prcv), transmissible gastroenteritis virus (tgev) and porcine epidemic diarrhoea virus (pedv) in feeder pigs shortly after their entry into fattening units was examined. ten groups of pigs with acute respiratory disease during the months september to october 1991 and seven groups of pigs with acute diarrhoea during the months february to march 1992 were investigated. on arrival in the fattening h ... | 1994 | 7900243 |
| use of nonradioactive cdna probes to differentiate porcine respiratory coronavirus and transmissible gastroenteritis virus isolates. | | 1996 | 8744748 |
| evidence for a putative second receptor for porcine transmissible gastroenteritis virus on the villous enterocytes of newborn pigs. | aminopeptidase-n (apn) has been identified [b. delmas, j. gelfi, r. l'haridon, l. k. vogel, h. sjostrom, o. noren, and h. laude, nature (london) 357:417-420, 1992] as a major receptor for porcine transmissible gastroenteritis virus (tgev). binding of tgev to villous enterocytes from the jejuna of newborn pigs is saturable and at a higher level than that of binding of virus to newborn cryptal enterocytes or to enterocytes from older piglets (h. m. weingartl and j. b. derbyshire, vet. microbiol. 3 ... | 1994 | 7933108 |
| lymphocyte proliferation responses of pigs inoculated with transmissible gastroenteritis virus or porcine respiratory coronavirus. | cell-mediated immunity was evaluated in intestinal, respiratory, and systemic lymphoid tissues of pigs exposed when 11 days old to virulent transmissible gastroenteritis virus (tgev), attenuated tgev, or porcine respiratory coronavirus (prcv), 3 antigenically related porcine coronaviruses with distinct enteric and respiratory tissue tropisms. mononuclear cells were prepared from mesenteric lymph nodes (mln), bronchial lymph nodes (bln), and spleens of pigs and tested for virus-specific responses ... | 1994 | 8017695 |
| pathogenicity of porcine respiratory coronavirus isolated in québec. | porcine respiratory coronavirus (prcv) is present in many countries, including canada, but controversy still exists concerning its pathogenicity. eight-week-old piglets were inoculated intratracheally with a quebec prcv isolate (1q90). two contact piglets were kept with the inoculated animals. three animals served as control. polypnea and dyspnea were the main clinical signs observed. diffuse bronchioloalveolar damage occurred 24 hours postinoculation. changes compatible with bronchointerstitial ... | 1994 | 8069830 |
| immunization of pregnant gilts with prcv induces lactogenic immunity for protection of nursing piglets from challenge with tgev. | the level of passive protection against transmissible gastroenteritis virus (tgev) was evaluated by experimentally infecting 12 pregnant gilts with different doses of porcine respiratory coronavirus (prcv) and challenging their litters at 4 days of age. an overall survival rate of 70% was found for piglets nursing the 12 prcv-infected gilts, compared to a 16% survival rate for piglets of nine uninfected control gilts. six of the prcv-infected gilts had adequate levels of immunity to resist infec ... | 1993 | 8128601 |
| contribution of antibody-secreting cells induced in mucosal lymphoid tissues of pigs inoculated with respiratory or enteric strains of coronavirus to immunity against enteric coronavirus challenge. | two antigenically related porcine coronaviruses, transmissible gastroenteritis virus (tgev) which infects primarily the intestinal tract and causes severe diarrhea, and porcine respiratory coronavirus (prcv) which infects the respiratory tract and causes subclinical or mild respiratory infections, presented a unique opportunity to study the interrelationship of gut-(galt) and bronchus-associated lymphoid tissues (balt) and their contribution to protective immunity against tgev infection. pigs we ... | 1994 | 8144965 |
| sequence of the spike protein of the porcine epidemic diarrhoea virus. | the complete sequence of the spike (s) gene of the br1/87 isolate of porcine epidemic diarrhoea virus (pedv) was determined from cdna clones. the predicted polypeptide was 1383 amino acids long, contained 29 potential n-linked glycosylation sites and showed structural features similar to those of the coronavirus spike protein. the pedv s protein, like that of the members of the transmissible gastroenteritis virus (tgev)-related subset, lacks a proteolytic site to yield cleaved amino and carboxy ... | 1994 | 8176382 |
| the use of pcr genome mapping for the characterisation of tgev strains. | previous studies on different transmissible gastroenteritis virus (tgev) strains, including porcine respiratory coronavirus (prcv), have identified regions within the genome that are polymorphic as regards insertions and deletions. for example the 672 base deletion within the s gene and multiple deletions 5', within and 3' of the orf-3a gene were detected in strains of prcv. the presence of deletions may be associated with a change in the virulence, attenuation or tissue tropism of the isolate. ... | 1993 | 8209745 |
| transmissible gastroenteritis virus and porcine respiratory coronavirus: molecular characterization of the s gene using cdna probes and nucleotide sequence analysis. | two transmissible gastroenteritis virus (tgev, miller strain) cdna clones were identified and their nucleotide sequences determined. the clones were non-overlapping and were located in the 5' region of the s glycoprotein gene. the tgev clone pe21 contained 381 bp of the s glycoprotein gene and had > 98% nucleotide and amino acid sequence homology with the purdue (p115) strain of tgev and over 87% sequence homology with feline infectious peritonitis virus (fipv). the tgev clone, pd24, contained 2 ... | 1993 | 8209764 |
| an overview of successful tgev vaccination strategies and discussion on the interrelationship between tgev and prcv. | porcine respiratory coronavirus (prcv) is a new variant of tge with an altered pathogenesis. prcv multiplies mainly in tonsilar tissues and the respiratory tract. there are no enteric symptoms and in experimentally infected pigs, even the respiratory tract infection is usually asymptomatic. prcv is spread aerogenically through herds and the significance of prcv as a pathogen in swine has yet to be determined. despite the differences in pathogenesis and tissue tropism, the behavior of tgev and pr ... | 1993 | 8209768 |
| construction of a recombinant adenovirus for the expression of the glycoprotein s antigen of porcine respiratory coronavirus. | | 1993 | 8209769 |
| competition elisa, using monoclonal antibodies to the transmissible gastroenteritis virus (tgev) s protein, for serologic differentiation of pigs infected with tgev or porcine respiratory coronavirus. | monoclonal antibodies (mab) to subsite a (25c9) and subsite d (44c11) of the s protein of transmissible gastroenteritis virus (tgev) were used in a blocking elisa on fixed tgev-infected swine testis cells to differentiate sera from pigs experimentally inoculated with either tgev or porcine respiratory coronavirus (prcv). serum samples were obtained from pigs at various intervals from postinoculation day (pid) 0 through at least pid 22 to 40. eleven-day-old pigs, seronegative for tgev-neutralizin ... | 1993 | 8381626 |
| intestinal protection against challenge with transmissible gastroenteritis virus of pigs immune after infection with the porcine respiratory coronavirus. | an infection of pigs with the porcine respiratory coronavirus (prcv) induces antibodies which neutralize the enteropathogenic transmissible gastroenteritis virus (tgev) and prcv to the same titre. in the present study, 10-week-old seronegative pigs (n = 8), pigs immune following tgev inoculation (n = 4) or pigs immune following aerosol (n = 8) or intragastric inoculation (n = 4) with prcv were challenged with tgev. whereas tgev-immune pigs were completely protected against challenge, all prcv-im ... | 1993 | 8382421 |
| isotype-specific antibody-secreting cells to transmissible gastroenteritis virus and porcine respiratory coronavirus in gut- and bronchus-associated lymphoid tissues of suckling pigs. | antibody-secreting cells (asc) were enumerated in gut- and bronchus-associated lymphoid tissues of pigs exposed to three antigenically related coronaviruses: virulent transmissible gastroenteritis virus (tgev), attenuated tgev, and porcine respiratory coronavirus (prcv). exposure of 11-day-old pigs to virulent tgev resulted in severe gastroenteritis and virus shedding mainly in feces but also to a limited extent in nasal secretions. prcv and attenuated tgev exposure produced no clinical signs an ... | 1993 | 8386204 |
| natural infection with the porcine respiratory coronavirus induces protective lactogenic immunity against transmissible gastroenteritis. | our objective was to evaluate the level of passive protection against transmissible gastroenteritis (tge) among 57 newborn piglets nursing from seven seropositive sows previously naturally infected with porcine respiratory coronavirus (prcv). after challenge exposure we observed mortality rates of 44% for litters of seven prcv-infected sows, 40% for litters of four sows orally immunized with the attenuated tgev strain nouzilly, and 91% for litters of seven seronegative susceptible sows. a blocki ... | 1989 | 2560280 |
| porcine respiratory coronavirus: molecular features and virus-host interactions. | since 1984, a previously unrecognized respiratory coronavirus, causing a mostly unapparent infection, has rapidly and massively spread within the swine population in europe, and few years later, a virus with similar characteristics has been identified in the usa. the agent, designated prcv, appears to be derived from the porcine enteric coronavirus tgev. the aim of the present article is to review comprehensively the state of the knowledge about this new virus and its infection. the review inclu ... | 1993 | 8393722 |
| cellular immune responses of pigs after primary inoculation with porcine respiratory coronavirus or transmissible gastroenteritis virus and challenge with transmissible gastroenteritis virus. | the contribution of cell-mediated immunity to protective immunity against virulent transmissible gastroenteritis virus (tgev) infection conferred by primary porcine respiratory coronavirus (prcv) or tgev exposure was assessed in pigs that were challenged with tgev 24 days after a primary oronasal inoculation with prcv or tgev when 11 days old. prcv exposure induced partial protection against tgev challenge in suckling pigs based upon a decreased number of diarrhea cases (42% vs. 90% in age-match ... | 1995 | 8533315 |
| cloning and sequencing of a 8.4-kb region from the 3'-end of a taiwanese virulent isolate of the coronavirus transmissible gastroenteritis virus. | the nucleotide sequence (8396 nucleotides) was determined, from the 3'-end of the putative polymerase gene to the poly(a) tail, for a taiwanese virulent isolate, tfi, of transmissible gastroenteritis virus (tgev). the tfi nucleotide sequence had very high identity to the british virulent field isolate fs772/70 (98.3%), the attenuated purdue 115 (96.7%) and from the s gene to orf-4 gene region, to the low passaged virulent miller (98.3%) strains of tgev. comparison of the tfi s protein sequence w ... | 1995 | 8546012 |
| an adenovirus recombinant expressing the spike glycoprotein of porcine respiratory coronavirus is immunogenic in swine. | the full-length spike (s) gene of porcine respiratory coronavirus (prcv) was inserted into the genome of human adenovirus type 5 downstream of the early transcription region 3 promoter. the recombinant virus replicated in cultures of the swine testicle st cell line and directed the synthesis of s antigen with a maximum yield of approximately 26 micrograms per 10(6) cells. the antigen was cell-associated except in the late phase of the infection, when a small amount (3.5 micrograms per 10(6) cell ... | 1996 | 8627235 |
| induction of protective immunity against transmissible gastroenteritis virus after exposure of neonatal pigs to porcine respiratory coronavirus. | to test the ability of porcine respiratory coronavirus (prcv) to induce protective immunity to antigenically related transmissible gastroenteritis virus (tgev) in neonatal pigs. | 1996 | 8633800 |
| contribution of passive immunity to porcine respiratory coronavirus to protection against transmissible gastroenteritis virus challenge exposure in suckling pigs. | to determine the ability of porcine respiratory coronavirus (prcv) infections to induce passive immunity in suckling pigs to transmissible gastroenteritis virus (tgev) challenge exposure. design and animals: 4 tgev seronegative sows and their litters (group a) served as controls, whereas 2 other groups (b and c) of sows (also tgev seronegative) were oronasally inoculated with live prcv during 1 or 2 subsequent pregnancies, respectively. | 1996 | 8723879 |
| isolation of porcine respiratory coronavirus from pigs affected with porcine reproductive and respiratory syndrome. | four cytopathogenic viruses were isolated in cpk cells derived from porcine kidneys from tonsils and lungs of 3 of 15 pigs affected with porcine reproductive and respiratory syndrome virus. physicochemically and morphologically, the isolates were similar to a coronavirus. the isolates were not distinguished from transmissible gastroenteritis virus (tgev) by a neutralization test using polyclonal antibodies, but differentiated from tgev by monoclonal antibodies capable of discriminating between t ... | 1996 | 8741277 |
| immunohistochemistry of transmissible gastroenteritis virus antigens in fixed paraffin-embedded tissues. | an immunohistochemistry technique was developed using fixed tissues to study the presence and location of transmissible gastroenteritis virus (tgev) antigens in situ. experimentally infected gnotobiotic and conventional pigs as well as pigs with natural tgev infection were examined. the staining technique was based on detection of the major structural protein of tgev, the nucleocapsid, by using a pool of 3 monoclonal antibodies. formalin and periodate-lysine-paraformaldehyde (plp)-fixed intestin ... | 1996 | 8744736 |
| transmissible gastroenteritis coronavirus, but not the related porcine respiratory coronavirus, has a sialic acid (n-glycolylneuraminic acid) binding activity. | the hemagglutinating activity of transmissible gastroenteritis virus (tgev), an enteric porcine coronavirus, was analyzed and found to be dependent on the presence of alpha-2,3-linked sialic acid on the erythrocyte surface. n-glycolylneuraminic acid was recognized more efficiently by tgev than was n-acetylneuraminic acid. for an efficient hemagglutination reaction the virions had to be treated with sialidase. this result suggests that the sialic acid binding site is blocked by virus-associated c ... | 1996 | 8764078 |
| expression and immunogenicity of the spike glycoprotein of porcine respiratory coronavirus encoded in the e3 region of adenovirus. | the full length spike (s) gene of porcine respiratory coronavirus (prcv) was inserted into the genome of human adenovirus type 5 downstream of the early transcription region 3 promoter. the recombinant virus replicated in cultures of the swine testicle st cell line and directed the synthesis of s antigen to an amount of approximately 33 micrograms per 10(6) cells, as determined by elisa. the antigen was cell-associated except in the late phase of the infection, when a low amount (4 micrograms pe ... | 1995 | 8830490 |
| cellular receptors for transmissible gastroenteritis virus on porcine enterocytes. | the activity of aminopeptidase-n (apn), reported to be a major receptor for porcine transmissible gastroenteritis virus (tgev), in enterocyte fractions harvested from the jejunal villi and crypts of newborn and weaned piglets, did not correspond with the levels of saturable virus binding previously demonstrated for the same fractions. plasma membranes prepared from enterocytes harvested from the jejunal villi of a newborn piglet were used in the preparation of a monoclonal antibody (mab) which b ... | 1995 | 8830502 |
| molecular differentiation of transmissible gastroenteritis virus and porcine respiratory coronavirus strains. correlation with antigenicity and pathogenicity. | transmissible gastroenteritis virus (tgev) causes an economically important enteric disease of swine. differences in the pathogenicity, antigenicity and tissue tropism have been observed among porcine coronaviruses. although porcine respiratory coronavirus (prcv) is antigenically similar but not identical to tgev isolates, these respiratory coronaviruses differ markedly in pathogenicity and tissue tropism compared to tgev isolates. using a reverse transcriptase/polymerase chain reaction-restrict ... | 1995 | 8830506 |
| in situ hybridization technique for the detection of swine enteric and respiratory coronaviruses, transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv), in formalin-fixed paraffin-embedded tissues. | the in situ hybridization (ish) technique was developed to detect the swine coronaviruses, transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv), in cell culture and tissue sections from tgev-or prcv-infected pigs. the 35s-labeled rna probes were generated from two plasmids ppsp.fp1 and ppsp.fp2 containing part of the s gene of tgev. the procedure was first standardized in cell cultures. the radiolabeled ppsp.fp2 probe detected both tgev and prcv in virus-inoculat ... | 1996 | 8882645 |
| mucosal immunity: an overview and studies of enteric and respiratory coronavirus infections in a swine model of enteric disease. | based on the tenet of a common mucosal immune system, antigenic stimulation at one mucosal site results in the distribution of antigen-specific iga precursor cells to distant mucosal sites. however, recent studies suggest that functional compartmentalization and limited reciprocity may exist within some components of the common mucosal immune system. although oral immunization is often very effective in inducing immunity to respiratory pathogens, the converse (respiratory immunization to prevent ... | 1996 | 8988861 |
| dual infections of feeder pigs with porcine reproductive and respiratory syndrome virus followed by porcine respiratory coronavirus or swine influenza virus: a clinical and virological study. | dual infections of pigs with porcine reproductive and respiratory syndrome virus (prrsv) followed by a second common respiratory virus, either porcine respiratory coronavirus (prcv) or swine influenza virus (siv), were studied. the aim was to determine if dual infections, as compared to single virus infections, result in enhanced clinical manifestations. it was also examined if prrsv replication affects replication of prcv or siv in the respiratory tract. groups of conventional 10 week old pigs ... | 1996 | 9054128 |
| immunohistochemical identification of porcine respiratory coronavirus antigen in the lung of conventional pigs. | nine 3-week-old conventional pigs were inoculated intranasally with a korean isolate of porcine respiratory coronavirus (prcv). three 3-week-old conventional pigs were kept as noninoculated controls. three inoculated and one control pig were euthanatized at 5, 10, and 15 days postinoculation (dpi), respectively. all nine inoculated pigs developed respiratory disease. interstitial pneumonia characterized by mononuclear inflammatory cell infiltration into alveolar septa were seen microscopically i ... | 1997 | 9066087 |
| detection of porcine respiratory coronavirus and transmissible gastroenteritis virus by an enzyme-linked immunosorbent assay. | an enzyme-linked immunosorbent assay (elisa) for the detection of transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) was developed. a bovine tgev-specific polyclonal antibody was purified by affinity chromatography with the trio bioprocessing system and was used as the capture antibody, at a concentration of 1.5 micrograms/well. the f5.39 monoclonal antibody was obtained by the fusion of spleen lymphocytes from tgev immunized mice with ns-1 myeloma cells. this ... | 1994 | 9133060 |
| an overview of immunological and genetic methods for detecting swine coronaviruses, transmissible gastroenteritis virus, and porcine respiratory coronavirus in tissues. | transmissible gastroenteritis (tge) is an enteric disease of swine caused by a coronavirus, designated as transmissible gastroenteritis virus (tgev). commonly used methods for tgev detection include viral isolation and detection of the viral antigen by indirect immunofluorescence (ifa), immunoperoxidase, and immunogold silver staining. each of these techniques has some advantages and disadvantages. in general ifa and immunohistochemistry are preferred over viral isolation as tgev isolation is no ... | 1997 | 9191988 |
| pathogenicity and sequence analysis studies suggest potential role of gene 3 in virulence of swine enteric and respiratory coronaviruses. | coronaviruses have been commonly associated with enteric and respiratory diseases. two of the swine coronaviruses, namely transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv), have been extensively studied. tgev replicates in both the enteric and respiratory tracts and causes enteric disease, whereas, prcv replicates in the respiratory tract with limited to no replication in the enteric tract. we have isolated prcv from swine herds with respiratory disease and ha ... | 1997 | 9192036 |
| a sero-epizootiological study of porcine respiratory coronavirus in belgian swine. | a porcine respiratory coronavirus (prcv), antigenically closely related to transmissible gastroenteritis virus (tgev), appeared in the european swine population in 1984. the present serological study was performed to obtain insight into the epizootiology of prcv and of tgev. prcv-induced neutralizing antibodies were found in 90.6 per cent of the 160 sera collected from sows at slaughter, demonstrating the enzootic appearance of prcv in the belgian swine population. a serological study of fatteni ... | 1993 | 8388592 |
| experimental reproduction of pneumonia in gnotobiotic pigs with porcine respiratory coronavirus isolate ar310. | the pathogenicity of porcine respiratory coronavirus (prcv) isolate ar310 was determined for gnotobiotic pigs. prcv-ar310 was isolated from the intestines of a nursery pig from a herd with endemic transmissible gastroenteritis. the ar310 isolate was plaque purified and cell culture propagated, passed once in a gnotobiotic pig, then used as inoculum for a gnotobiotic pig pathogenicity study. eight pigs were inoculated oronasally with 2 x 10(6) plaque-forming units of prcv-ar310. eight pigs served ... | 1993 | 8389599 |
| field isolates of transmissible gastroenteritis virus differ at the molecular level from the miller and purdue virulent and attenuated strains and from porcine respiratory coronaviruses. | the diversity in selected regions of the transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) genomes was analyzed among known tgev and prcv strains and field isolates. the n-terminal half of the spike (s) glycoprotein gene and open reading frames (orf) 3, 3-1 and 4 were amplified by reverse transcriptase reaction and polymerase chain reaction (rt/pcr), and analyzed using restriction fragment length polymorphism (rflp) patterns of the amplified dna. reference tge ... | 1998 | 9637293 |
| in vivo and in vitro interferon (ifn) studies with the porcine reproductive and respiratory syndrome virus (prrsv). | some of the interactions between the porcine reproductive and respiratory syndrome virus (prrsv) and the porcine interferon-alpha (ifn-alpha) system were studied. in a first experiment, it was shown that pretreatment of primary porcine alveolar macrophages (ams) with recombinant porcine (rpo) ifn-alpha 1 resulted in significant reductions of prrsv yield and numbers of antigen expressing cells. in a second experiment, sensitivity of prrsv to ifn-alpha was confirmed in vivo. in pigs inoculated wit ... | 1998 | 9782316 |
| one-tube fluorogenic reverse transcription-polymerase chain reaction for the quantitation of feline coronaviruses. | a one-tube reverse transcription-polymerase chain reaction (rt-pcr) for absolute feline coronavirus (fcov) quantitation was developed. the assay is based on the 5' nuclease activity of the thermus flavus (tfl) polymerase and a fluorogenic probe which generates fluorescence when it is cleaved. the fluorogenic probe, also called taqman(tm) probe (perkin elmer, foster city, usa), is an oligonucleotide designed to bind between the two pcr primers to the target cdna and is labeled with a reporter and ... | 1999 | 10029323 |
| evaluation of the baculovirus-expressed s glycoprotein of transmissible gastroenteritis virus (tgev) as antigen in a competition elisa to differentiate porcine respiratory coronavirus from tgev antibodies in pigs. | the spike (s) glycoprotein of the miller strain of transmissible gastroenteritis virus (tgev) was recently cloned and expressed in baculovirus. the recombinant s protein was used as the coating antigen in a competition (blocking) enzyme-linked immunosorbent assay (elisa) in combination with monoclonal antibodies to the s protein epitope a (conserved on tgev and porcine respiratory coronavirus [prcv]) or epitope d (present on tgev only) to differentiate prcv- from tgev-induced antibodies. one set ... | 1999 | 10353350 |
| complete genomic sequences, a key residue in the spike protein and deletions in nonstructural protein 3b of us strains of the virulent and attenuated coronaviruses, transmissible gastroenteritis virus and porcine respiratory coronavirus. | transmissible gastroenteritis virus (tgev) isolates that have been adapted to passage in cell culture maintain their infectivity in vitro but may lose their pathogenicity in vivo. to better understand the genomic mechanisms for viral attenuation, we sequenced the complete genomes of two virulent tgev strains and their attenuated counterparts: virulent tgev miller m6 and attenuated tgev miller m60 and virulent tgev purdue and attenuated tgev purdue p115, together with the isu-1 strain of porcine ... | 2007 | 17023013 |
| characterisation of a recent virulent transmissible gastroenteritis virus from britain with a deleted orf 3a. | analyses of transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) isolates have suggested that tropism and pathogenicity are influenced by the spike protein and orf 3. in general, enteric viruses (tgev) have been shown to contain intact spike and orf 3 genes, whilst respiratory isolates (prcv) have major deletions within both regions. virulence has been correlated to a functional orf 3. here, sequence analysis of a recent isolate of virulent tgev, revealed a varia ... | 1999 | 10365166 |
| porcine respiratory coronavirus in quebec: serological studies using a competitive inhibition enzyme-linked immunosorbent assay. | porcine respiratory coronavirus (prcv) was identified for the first time in quebec, using a blocking enzyme-linked immunosorbent assay (elisa). unlike the virus neutralization test (vnt), this elisa was able to distinguish transmissible gastroenteritis virus (tgev) from prcv. among the 15 seropositive fattening herds from group a, sera containing prcv antibodies represented 74.8%, whereas those with tgev antibodies represented only 7.2%. in group b, which consisted of 15 sow herds, nine herds ex ... | 1992 | 17424115 |
| the emergence of porcine circovirus 2b genotype (pcv-2b) in swine in canada. | since late 2004, the swine industry in the province of quebec has experienced a significant increase in death rate related to postweaning multisystemic wasting syndrome (pmws). to explain this phenomenon, 2 hypotheses were formulated: 1) the presence of a 2nd pathogen could be exacerbating the porcine circovirus 2 (pcv-2) infection, or 2) a new and more virulent pcv-2 strain could be infecting swine. in 2005, 13 pmws cases were submitted to the quebec provincial diagnostic laboratory and pcv-2 w ... | 2007 | 17824323 |
| altered pathogenesis of porcine respiratory coronavirus in pigs due to immunosuppressive effects of dexamethasone: implications for corticosteroid use in treatment of severe acute respiratory syndrome coronavirus. | the pathogenesis and optimal treatments for severe acute respiratory syndrome (sars) are unclear, although corticosteroids were used to reduce lung and systemic inflammation. because the pulmonary pathology of porcine respiratory coronavirus (prcv) in pigs resembles sars, we used prcv as a model to clarify the effects of the corticosteroid dexamethasone (dex) on coronavirus (cov)-induced pneumonia. conventional weaned pigs (n = 130) in one of four groups (prcv/phosphate-buffered saline [pbs] [n ... | 2007 | 17942563 |
| differential production of proinflammatory cytokines in the pig lung during different respiratory virus infections: correlations with pathogenicity. | the acute stages of infection with swine influenza virus (siv), porcine respiratory coronavirus (prcv) and porcine reproductive-respiratory syndrome virus (prrsv) were shown to differ in terms of clinical and lung inflammatory effects and proinflammatory cytokine profiles in bronchoalveolar lavage (bal) fluids. caesarian-derived colostrum-deprived pigs were inoculated intratracheally with one of the three viruses. siv infection was followed within 1 day post inoculation (d pi) by characteristic ... | 1999 | 10425240 |
| proinflammatory cytokines and viral respiratory disease in pigs. | swine influenza virus (siv), porcine respiratory coronavirus (prcv) and porcine reproductive and respiratory syndrome virus (prrsv) are enzootic viruses causing pulmonary infections in pigs. the first part of this review concentrates on known clinical and pathogenetic features of these infections. siv is a primary respiratory pathogen; prcv and prrsv, on the contrary, tend to cause subclinical infections if uncomplicated but they appear to be important contributors to multifactorial respiratory ... | 2000 | 10779199 |
| a potential role for tumour necrosis factor-alpha in synergy between porcine respiratory coronavirus and bacterial lipopolysaccharide in the induction of respiratory disease in pigs. | this study examined whether exposure of pigs to both porcine respiratory coronavirus (prcv) and bacterial lipopolysaccharide (lps) can potentiate respiratory disease and lung secretion of tumour necrosis factor-a (tnf-alpha) and interleukin-1 (il-1). caesarian-derived colostrum-deprived pigs were inoculated intratracheally with prcv, with lps from escherichia coli o111:b4 (20 microg/kg), or with a combination of the two, and killed at set times after inoculation. clinical signs, virus replicatio ... | 2000 | 10882086 |
| development of a reverse transcription-nested polymerase chain reaction assay for differential diagnosis of transmissible gastroenteritis virus and porcine respiratory coronavirus from feces and nasal swabs of infected pigs. | transmissible gastroenteritis virus (tgev), a coronavirus, replicates in intestinal enterocytes and causes diarrhea in young pigs. porcine respiratory coronavirus (prcv), a spike (s) gene natural deletion mutant of tgev, has a respiratory tissue tropism and causes mild or subclinical respiratory infections. conventional antigen-based diagnostic tests fail to differentiate tgev and prcv, and a blocking elisa test to serologically differentiate tgev/prcv-infected pigs is conducted on convalescent ... | 2000 | 10907874 |
| porcine reproductive and respiratory syndrome virus modifies innate immunity and alters disease outcome in pigs subsequently infected with porcine respiratory coronavirus: implications for respiratory viral co-infections. | the innate immune response is critical for host defence against respiratory coronaviruses (covs). this study demonstrated that an ongoing respiratory virus infection compromises innate immune responses and affects the pathogenesis of a respiratory cov co-infection. an innate immunosuppressive respiratory virus infection was established by infecting weaned pigs with porcine reproductive and respiratory syndrome virus (prrsv); 10 days later, the pigs were exposed to porcine respiratory coronavirus ... | 2009 | 19656969 |
| molecular characterization and pathogenesis of transmissible gastroenteritis coronavirus (tgev) and porcine respiratory coronavirus (prcv) field isolates co-circulating in a swine herd. | tgev replicates in intestinal enterocytes and causes diarrhea in young pigs. prcv, a spike (s) gene deletion mutant of tgev with an altered respiratory tissue tropism, causes mild or subclinical respiratory infections. comparisons of tgev and prcv strains suggest that tropism and pathogenicity are influenced by the s gene and orf3, respectively. recently, outbreaks of tge of reduced virulence were reported in the field. we investigated a similar suspect tgev outbreak of reduced virulence in nurs ... | 2000 | 10948987 |
| seroprevalence of porcine respiratory coronavirus in selected korean pigs. | a total of 446 serum samples from 88 herds in korea were examined for antibody to porcine respiratory coronavirus (prcv) using blocking enzyme-linked immunosorbent assay (elisa). all serum samples were collected from 24- to 26-week-old finishing pigs between december 1998 and june 1999. by elisa, 237 out of 446 sera tested (53.1%) and 54 out of 88 sampled herds (61.3%) were positive against prcv. of 446 sera from 88 herd tested, 185 (41.5%) serum samples from 22 (25%) herds were seronegative aga ... | 2000 | 10960715 |
| field validation of a commercial blocking elisa to differentiate antibody to transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus and to identify tgev-infected swine herds. | a commercially available blocking elisa was analyzed for its ability to identify antibodies to porcine coronaviruses (transmissible gastroenteritis virus [tgev] or porcine respiratory coronavirus [prcv]), to differentiate antibodies to tgev and prcv, and to identify tgev-infected herds. nine sera from uninfected pigs, 34 sera from 16 pigs experimentally infected with tgev, and sera from 10 pigs experimentally infected with prcv were evaluated using both the tgev/prcv blocking elisa and a virus n ... | 2002 | 11939346 |
| 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 ... | 2002 | 12072230 |
| 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 ... | 2002 | 12423025 |
| neutralizing antibody decay and lack of contact transmission after inoculation of 3- and 4-day-old piglets with porcine respiratory coronavirus. | ten female neonatal piglets were infected with porcine respiratory coronavirus (prcv) to measure the decay of a specific neutralizing antibody. by 42 weeks after exposure,1 of the gilts was serologically negative (< 5) for prcv, and by 48 weeks 2 more gilts were serologically negative. these data demonstrate that young mature gilts can be serologically negative, yet they could have been exposed to prcv. sentinel pigs were commingled with the prcv-infected pigs at 8 weeks after exposure, and no v ... | 2002 | 12423041 |
| pathogenicity of three isolates of porcine respiratory coronavirus in the usa. | the pathogenicity of three isolates of porcine respiratory coronavirus (ar310, lepp and 1894) from the usa was assessed in specific pathogen-free pigs. pigs inoculated with 1894 developed mild respiratory disease and pigs inoculated with ar310 and lepp developed moderate respiratory disease from four to 10 days after they were inoculated, but all the pigs recovered fully by 14 days after inoculation. gross and microscopic examination revealed mild (1894) to moderate (ar310 and lepp) multifocal b ... | 2003 | 12678259 |