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transmissible enteritis of turkeys: experimental inoculation studies with tissue-culture-adapted turkey and bovine coronaviruses.four quebec isolates of turkey enteric coronaviruses (tcvs) and three isolates of bovine enteric coronaviruses (bcvs) were serially propagated in hrt-18 and compared for their pathogenicity in turkey embryos and turkey poults. by immunoelectron microscopy, hemagglutination-inhibition, and western immunoblotting assays, tissue-culture-adapted quebec tcv isolates were found to be closely related to the reference minnesota strain of tcv and the mebus strain of bcv. genomic relationships between tcv ...19911664719
characterization and location of the structural polypeptides of turkey enteric coronavirus using monoclonal antibodies and enzymatic treatments. 19901715664
evidence of close relatedness between turkey and bovine coronaviruses. 19901966438
detection of turkey enteric coronavirus by enzyme-linked immunosorbent assay and differentiation from other coronaviruses.a double-antibody elisa for the detection of coronaviruses in intestinal contents from turkey poults with diarrhea was developed. antibodies were raised in rabbits and guinea pigs against a minnesota isolate of turkey enteric coronavirus (tcv) propagated in embryonating turkey eggs and were purified by density-gradient centrifugation. the specificity of antisera was confirmed by hemagglutination-inhibition and immunoelectron microscopy. absorption of anti-tcv hyperimmune sera with egg extracts o ...19892541641
ultrastructure and protein a-gold immunolabelling of hrt-18 cells infected with turkey enteric coronavirus.the minnesota strain of turkey enteric coronavirus (tcv) was propagated in hrt-18 cells, a cell line derived from human rectum adenocarcinoma. a productive non-cytopathic infection was established, without a previous adaptation, in these cells as shown by the specific hemagglutinating activity in cell culture supernatants. a post-embedding immunochemical technique, using specific antiserum directed against the original egg-adapted virus and colloidal-gold-labelled protein a as the electron-dense ...19892548321
intracellular synthesis and processing of the structural glycoproteins of turkey enteric coronavirus.pulse labeling of cells with [35s]methionine or [3h]glucosamine at different times after infection, followed by sds-page and western immunoblotting analysis using rabbit anti-tcv hyperimmune serum, was used to resolve and identify tcv-induced intracellular proteins. the viral structural proteins (gp 200, gp 140/gp 66, gp 100/gp 120, p 52, and gp 24/p 20) were detected in radiolabeled cell extracts by 9 to 12 hours post-infection, as well as two possible non-structural proteins with apparent mol. ...19892774975
coronaviruses associated with outbreaks of transmissible enteritis of turkeys in quebec: hemagglutination properties and cell cultivation.coronaviruses were observed by electron microscopy in the intestinal contents of turkeys in quebec flocks where repeated outbreaks of enteritis occurred. three isolates could be serially propagated in turkey embryos inoculated by the amniotic route with clarified intestinal contents. purification and concentration of viral particles contained in intestinal contents of infected embryos were achieved by precipitation with polyethylene glycol and ultracentrifugation on sucrose density gradients. th ...19863015116
immunofluorescence studies on the early pathogenesis of hemorrhagic enteritis virus infection in turkeys and chickens.chickens and turkeys not previously exposed to hemorrhagic enteritis virus (hev) were inoculated orally with the virus. birds were necropsied each day from the first to the eighth day following inoculation, and specimens from various tissues were collected for examination. clinical illness was noted only in turkeys, although intestinal hemorrhages and swollen, necrotic spleens were seen in both species. the distribution and localization of viral antigens in various tissues and peripheral blood l ...19826284108
response of specific-pathogen-free turkeys to vaccines derived from marble spleen disease virus and hemorrhagic enteritis virus.tissue-culture-propagated marble spleen disease virus (msdv-tc) and two preparations of spleen homogenate (msdv-sh and msdv-sh-tc) were compared as anti-hemorrhagic enteritis virus (hev) vaccines in specific-pathogen-free turkeys. both types of vaccines spread horizontally among turkeys, induced anti-hev antibodies, and protected turkeys against challenge with virulent hev. antibody development and horizontal spread of virus occurred earlier in turkeys given msdv-sh or msdv-sh-tc than in those g ...19947832705
baculovirus expression of turkey coronavirus nucleocapsid protein.the nucleocapsid (n) gene of turkey coronavirus (tcv) was amplified by reverse transcriptase-polymerase chain reaction, cloned, and expressed in the baculovirus expression system. a recombinant baculovirus containing the tcv n gene (rbtcv/n) was identified by polymerase chain reaction and expression of tcv n protein as determined by western immunoblot analysis. two tcv-specific proteins, 52 and 43 kda, were expressed by rbtcv/n; one of these proteins, p52, was comparable in size to native tcv n ...200111332474
antigenic relationship of turkey coronavirus isolates from different geographic locations in the united states.the purpose of the present study was to examine the antigenicity of turkey coronavirus (tcv) isolates from various geographic areas with antibodies to different viruses. seventeen isolates of tcv were recovered from intestinal samples submitted to animal disease diagnostic laboratory, purdue university, from turkey farms located in different geographic areas. the prototype tcv minnesota isolate (tcv-atcc) was obtained from the american type culture collection. intestinal sections were prepared f ...200212061660
existence of gene 5 indicates close genomic relationship of turkey coronavirus to infectious bronchitis virus.a segment of genomic rna extending from the 3'-end of the membrane (m) protein gene to the 5'-end of the nucleocapsid (n) protein gene of turkey coronavirus (tcv) was amplified by reverse transcription-polymerase chain reaction (rt-pcr). the primers were derived from the corresponding sequences of infectious bronchitis virus (ibv). the pcr products were cloned and sequenced and their nucleic acid structure and similarity to the published sequences of ibv were analyzed. gene 5 containing two over ...200212387503
prevalence of infectious diseases in ring-necked pheasant flocks in poland.the health status of ring-necked pheasants in view of the prevalence of infectious diseases was estimated in polish pheasantries in the years 1997-2000. anatomicopathological, microbiological and serological examinations were carried out on birds derived from 26 pheasantries, including birds randomly selected from 18 flocks and sick or dead birds sent from 8 pheasantries. antibodies specific to the following viruses were detected in serum blood samples: he, ae, ap, reo, ai, adeno group 1, md, nd ...200314510048
differential detection of turkey coronavirus, infectious bronchitis virus, and bovine coronavirus by a multiplex polymerase chain reaction.the objective of the present study was to develop a multiplex polymerase chain reaction (pcr) method for differential detection of turkey coronavirus (tcov), infectious bronchitis coronavirus (ibv), and bovine coronavirus (bcov). primers were designed from conserved or variable regions of nucleocapsid (n) or spike (s) protein gene among tcov, ibv, and bcov and used in the same pcr reaction. reverse transcription followed by the pcr reaction was used to amplify a portion of n or s gene of the cor ...200616137773
isolation of a coronavirus from a green-cheeked amazon parrot (amazon viridigenalis cassin).a virus (av71/99) was isolated from a green-cheeked amazon parrot by propagation and passage in both primary embryo liver cells derived from blue and yellow macaw (ara ararauna) embryos and chicken embryo liver cells. electron microscopic examination of cytopathic agents derived from both types of cell cultures suggested that it was a coronavirus. this was confirmed using a pan-coronavirus reverse transcriptase polymerase chain reaction that amplified part of gene 1 that encodes the rna-dependen ...200616595304
complete genomic sequence analysis of infectious bronchitis virus ark dpi strain and its evolution by recombination.an infectious bronchitis virus arkansas dpi (ark dpi) virulent strain was sequenced, analyzed and compared with many different ibv strains and coronaviruses. the genome of ark dpi consists of 27,620 nucleotides, excluding poly (a) tail, and comprises ten open reading frames. comparative sequence analysis of ark dpi with other ibv strains shows striking similarity to the conn, gray, jmk, and ark 99, which were circulating during that time period. furthermore, comparison of the ark genome with oth ...200819102764
hemorrhagic enteritis of turkeys: influence of maternal antibody and age at exposure.the effect of maternal antibody (mab) to hemorrhagic enteritis (he) on the response of turkeys to infection with virulent and avirulent strains of he virus (hev) was examined. the influence of age at exposure and treatment with hev antibody on development of clinical he also was studied. mab protected poults from clinical he for up to 6 weeks of age. mab also interfered with vaccination against the disease for at least 5 weeks after hatching, as indicated by absence of hev antigen in spleens and ...19892559708
emergence of a group 3 coronavirus through recombination.analyses of turkey coronavirus (tcov), an enteric disease virus that is highly similar to infectious bronchitis virus (ibv) an upper-respiratory tract disease virus in chickens, were conducted to determine the adaptive potential, and genetic changes associated with emergence of this group 3 coronavirus. strains of tcov that were pathogenic in poults and nonpathogenic in chickens did not adapt to cause disease in chickens. comparative genomics revealed two recombination sites that replaced the sp ...201020022075
immunity to transmissible (coronaviral) enteritis of turkeys (bluecomb).turkey flocks recovering from natural and laboratory induced coronaviral enteritis developed lifelong immunity. virus neutralization tests indicated that neutralization capacity of serums from recovered turkeys was low. one-way cross challenge test using turkeys inoculated with various bluecomb isolates revealed close antigenic relationship or antigenic identity among bluecomb isolates. the controlled application of intestinal preparations containing coronavirus as a vaccination procedure had va ...1975164801
specific real-time reverse transcription-polymerase chain reaction for detection and quantitation of turkey coronavirus rna in tissues and feces from turkeys infected with turkey coronavirus.turkey coronavirus (tcov) infection causes acute atrophic enteritis in the turkey poults, leading to significant economic loss in the u.s. turkey industry. rapid detection, differentiation, and quantitation of tcov are critical to the diagnosis and control of the disease. a specific one-step real-time reverse transcription-polymerase chain reaction (rrt-pcr) assay for detection and quantitation of tcov in the turkey tissues was developed using a dual-labeled fluorescent probe. the fluorogenic pr ...201019917315
detection of turkey coronavirus in commercial turkey poults in brazil.poult enteritis complex has been incriminated as a major cause of loss among turkey poults in other countries. we have observed this in brazil, associated with diarrhoea, loss of weight gain and, commonly, high mortality. in this study, we have used the reverse transcriptase polymerase chain reaction (rt-pcr) to detect turkey coronavirus (tcov) in sick poults 30 to 120 days of age from a particular producer region in brazil. the rt-pcr was applied to extracts of intestine tissue suspensions, and ...200717364507
development of a multiplex reverse transcription-polymerase chain reaction diagnostic test specific for turkey astrovirus and coronavirus.a multiplex reverse transcription-polymerase chain reaction (rt-pcr) assay was developed for the simultaneous detection of two enteric viruses of poultry: turkey enteric coronavirus (tcv) and turkey astrovirus (tastv). pcr primers were designed to conserved regions within the nucleocapsid gene of tcv and to the polymerase gene of tastv-2. the primer pairs were successfully used in a multiplex rt-pcr to detect nucleic acid of tastv-2 and tcv. the test was optimized for use with intestines/feces f ...200415529975
a reverse transcriptase-polymerase chain reaction assay for the diagnosis of turkey coronavirus infection.this study reports on the development of a reverse transcriptase-polymerase chain reaction (rt-pcr) for the specific detection of turkey coronavirus (tcov). of the several sets of primers tested, 1 set of primers derived from the p gene and 2 sets derived from the n gene of tcov could amplify the tcov genome in the infected samples. the rt-pcr was sensitive and specific for tcov and did not amplify other avian rna and dna viruses tested except the infectious bronchitis virus (ibv). to overcome t ...200314667027
detection of antibody to turkey coronavirus by antibody-capture enzyme-linked immunosorbent assay utilizing infectious bronchitis virus antigen.an antibody-capture enzyme-linked immunosorbent assay (elisa) for detection of antibody to turkey coronavirus (tcv) utilizing infectious bronchitis virus (ibv) antigen was developed. anti-tcv hyperimmune turkey serum and normal turkey serum were used as positive or negative control serum for optimization of the elisa system. goat anti-turkey immunoglobulin g (light plus heavy chains) conjugated with horseradish peroxidase was used as detector antibody. the performance of the elisa system was eva ...200011006996
a novel "small round virus" inducing poult enteritis and mortality syndrome and associated immune alterations.the role of a novel "small round virus" (srv) isolated from poult enteritis and mortality syndrome (pems) cases in inducing pems and associated immune alterations was examined in this study. specific-pathogen-free and conventional poults were orally challenged with srv and/or turkey coronavirus and monitored for clinical signs. intestines, thymus, bursa, and spleens were examined for srv antigen at various days postinoculation (dpi). peripheral blood lymphocytes (pbls), thymocytes, and splenic l ...200010879906
high mortality and growth depression experimentally produced in young turkeys by dual infection with enteropathogenic escherichia coli and turkey coronavirus.six-day-old turkeys were inoculated with turkey coronavirus (tcv) and an enteropathogenic escherichia coli (epec) (isolate r98/5) that were isolated from poult enteritis and mortality syndrome (pems)-affected turkeys. turkeys inoculated with only r98/5 did not develop clinically apparent disease, and only mild disease and moderate growth depression were observed in turkeys inoculated with only tcv. turkeys dually inoculated with tcv and r98/5 developed severe enteritis with high mortality (38/48 ...200010737650
hemorrhagic enteritis in turkeys: purification and quantification of the virus.two methods for purifying the virus of hemorrhagic enteritis from infected turkey spleens are described. one procedure utilized precipitation with polyethylene glycol, and the other consisted of trichlorotrifluoroethane extraction. both procedures included sucrose-cesium chloride gradient centrifugation in the final purification step. the buoyant density of the viral fraction was 1.34 g/cm3, typical for adenoviral particles, and the size and morphologic characteristics of the virions observed by ...19836303291
further studies on in vitro and in vivo assays of hemorrhagic enteritis virus (hev).isolation of hemorrhagic enteritis virus (hev) from spleens of infected turkeys in the mdtc-rp19 lymphoblastoid cell line was compared with detection of hev antigen in the same spleens using the agar gel precipitation (agp) test. a concordance of 80% was found between the two assays. virus isolation had a sensitivity of 84% and a specificity of 88% compared with the agp test. rp19 cells were also susceptible to infection with several other avian adenoviruses, but such infection was easily differ ...19873039962
quantitation of hemorrhagic enteritis virus antigen and antibody using enzyme-linked immunosorbent assays.enzyme-linked immunosorbent assays (elisas) were developed to quantitate hemorrhagic enteritis virus (hev) antibodies in turkey sera and hev antigens in tissue extracts. these assays were more sensitive than the commonly used agar-gel precipitin tests in detecting antigen and antibody. the antibody-elisa was used to monitor the presence and decline of passive antibodies in turkey poults and the seroconversion of turkeys infected with hev. the antigen-elisa was carried out using a monoclonal anti ...19863028352
hemorrhagic enteritis of turkeys in california: serologic study of hemorrhagic enteritis virus antibody with an enzyme-linked immunosorbent assay.the incidence of hemorrhagic enteritis (he) infection in california turkeys was studied by testing 2220 turkey blood samples from 173 flocks for he virus (hev) antibody by the enzyme-linked immunosorbent assay (elisa). maternal antibody was detected at 1 day of age in all flocks tested, and it vanished after 3 weeks. acquired hev antibody appeared at 8 to 10 weeks, and 100% of the meat and breeder turkey flocks were positive after 11 weeks of age. hev infection occurred earlier in the meat flock ...19852992436
immunosuppressive effects of virulent strain of hemorrhagic enteritis virus in turkeys vaccinated against newcastle disease.one week after infection with a virulent strain of hemorrhagic enteritis virus (hev), turkeys were vaccinated for newcastle disease. the effect of a virulent strain of hev on turkeys' immune response to newcastle disease vaccine and the mitogenic response of their whole blood peripheral lymphocytes were examined. the results revealed a statistically significant difference (p less than .01) in the newcastle disease hemagglutination inhibition (ndhi) antibody titers from turkeys infected with viru ...19852986088
enzyme immunoassay studies on the serological response of turkeys to hemorrhagic enteritis virus.an enzyme-linked immunosorbent assay (elisa) was developed for the detection of antibodies in turkey serum to hemorrhagic enteritis virus. the elisa antigen was extracted from turkey spleens and partially purified with fluorocarbon. antibodies were demonstrated in serum samples of breeding and meat flocks that had been naturally exposed to infection. these samples were also examined in parallel by agar-gel precipitin (agp); most of the sera were agp-positive. elisa, however, was more sensitive i ...19852985040
viral agents associated with outbreaks of diarrhea in turkey flocks in quebec.the relative importance of various enteric viruses associated with diarrhea of turkey poults was investigated by an evaluation of specimens received since 1982. specimens originated from one to eight week old turkey poults, with mild to severe diarrhea, from 114 flocks in 42 commercial operations located in southern quebec. the acute phase of enteritis occurred usually in poults between two and four weeks of age. clarified intestinal contents were examined by direct electron microscopy and enzym ...19882832044
identification and location of the structural glycoproteins of a tissue culture-adapted turkey enteric coronavirus.the minnesota strain of turkey enteric coronavirus (tcv) was grown on a human rectal tumor (hrt-18) cell line in the presence of radiolabeled amino acids and glucosamine to analyse virion structural proteins. in addition to the 52,000 unglycosylated nucleocapsid protein, three major glycoprotein species were found to be associated with the viral envelope. a predominant glycosylated protein with a molecular weight of 22-24,000 represented the transmembrane matrix protein. larger glycoproteins wit ...19892673155
isolation and trypsin-enhanced propagation of turkey enteric (bluecomb) coronaviruses in a continuous human rectal adenocarcinoma cell line.turkey enteric coronavirus (tcv) from intestinal contents of diarrheal poults was isolated and serially propagated in hrt-18 cells, an established cell line derived from a human rectal adenocarcinoma. in these cells, tcv induced cytopathic changes, including polykaryocytosis, which depended on trypsin in the medium and incubation at 41 c. viral antigens could be demonstrated in the cytoplasm by immunofluorescence, and extracellular virus was detected by an elisa and negative electron microscopy. ...19892551201
antigenic and polypeptide structure of turkey enteric coronaviruses as defined by monoclonal antibodies.twenty-nine hybridoma cells lines, producing monoclonal antibodies (mabs) to the minnesota strain of turkey enteric coronavirus (tcv), have been established by fusion of sp2/0 myeloma cells with spleen cells from balb/c mice immunized with purified preparations of the egg-adapted or tissue culture-adapted virus. the hybridomas produced mainly igg2a or igg1 antibodies. western immunoblotting experiments with purified virus, and immunoprecipitation tests with [35s]methionine-labelled infected cell ...19892472464
sequence analysis of the turkey enteric coronavirus nucleocapsid and membrane protein genes: a close genomic relationship with bovine coronavirus.the 3' end of the turkey coronavirus (tcv) genome and the gene encoding the nucleocapsid protein (n) were cloned and sequenced. the gene encoding the membrane protein (m) was obtained by cloning a polymerase chain reaction (pcr)-amplified fragment obtained using bovine coronavirus (bcv)-specific primers. furthermore, five tcv dna fragments, obtained by pcr on rna from clinical specimens and corresponding to either the n terminus of the m protein or the complete m protein were also cloned and seq ...19911856695
genomic relationship between turkey and bovine enteric coronaviruses identified by hybridization with bcv or tcv specific cdna probes.genomic relationships between turkey and bovine coronavirus (tcv and bcv), which are currently placed in distinct antigenic groups, were demonstrated by hybridization using specific cdna probes. bcv-specific recombinant plasmid probes p 52, p 27, and p 247, holding inserts derived from (probably nonstructural) genes, and plasmids pn 17 and pn 9 holding the n and m gene, respectively, permitted the detection of isolates of both bcv and tcv with similar sensitivities. similarly, probing supernatan ...19911662038
immunopathogenesis of haemorrhagic enteritis virus (hev) in turkeys.infection of turkeys with the haemorrhagic enteritis virus (hev), a type ii avian adenovirus, results in varying rates of morbidity and mortality. the disease is characterised by splenomegaly, intestinal haemorrhage, sudden death and immunosuppression. the mechanisms of hev immunopathogenesis and immunosuppression are not fully understood. recent studies indicate that immune responses play a central role in disease pathogenesis. hev infects b cells and macrophages and induces necrosis as well as ...200010717290
detection and molecular characterization of enteric viruses in breeder turkeys.the present study was undertaken to detect and characterize enteric viruses (rotavirus, astrovirus, reovirus, and coronavirus) in breeder poults. five turkey breeder flocks were selected. faecal samples were collected from all flocks at 1 week of age and then every other week until the poults reached 9 weeks of age. the faecal samples were pooled in groups of five. of the 193 pools ("samples") tested by reverse transcription-polymerase chain reaction, 47.2%, 30.6%, and 10.4% samples were positiv ...201020390537
haemorrhagic enteritis of turkeys. 19901964777
identification and characterization of a neutralizing-epitope-containing spike protein fragment in turkey coronavirus.little is known about the neutralizing epitopes in turkey coronavirus (tcov). the spike (s) protein gene of tcov was divided into 10 fragments to identify the antigenic region containing neutralizing epitopes. the expression and antigenicity of s fragments was confirmed by immunofluorescence antibody (ifa) assay using an anti-histidine monoclonal antibody or anti-tcov serum. polyclonal antibodies raised against expressed s1 (amino acid position 1 to 573 from start codon of s protein), 4f/4r (482 ...201121594597
seroprevalence of turkey coronavirus in north american turkeys determined by a newly developed enzyme-linked immunosorbent assay based on recombinant antigen.turkey coronavirus (tcov) causes diarrhea in young turkey poults, but little is known about its prevalence in the field. to address this, the complete nucleocapsid gene was cloned and expressed in escherichia coli. expressed nucleocapsid gene produced two distinct proteins (52 and 43 kda); their specificity was confirmed by western blotting using two different monoclonal antibodies. recombinant n protein was purified and used as an antigen to develop an enzyme-linked immunosorbent assay (elisa) ...200818971306
antigenic characterization of a turkey coronavirus identified in poult enteritis- and mortality syndrome-affected turkeys.a turkey coronavirus (tcv [nc95]) was characterized by antigenic comparison with other avian and mammalian coronaviruses using immunofluorescence (fa) and immunoperoxidase (ip) procedures. based on fa and ip procedures, tcv (nc95) was determined to be antigenically indistinguishable from turkey enteric (bluecomb) coronavirus (tecv). in addition, tcv (nc95) and tecv were found to be closely related to infectious bronchitis virus (ibv); a one-way antigenic relationship was demonstrated. polyclonal ...19979356703
visual detection of turkey coronavirus rna in tissues and feces by reverse-transcription loop-mediated isothermal amplification (rt-lamp) with hydroxynaphthol blue dye.a sensitive reverse-transcription loop-mediated isothermal amplification (rt-lamp) assay was developed for the rapid visual detection of turkey coronavirus (tcov) infection. the reaction is performed in one step in a single tube at 65 °c for 45 min, with hydroxynaphthol blue (hnb) dye added prior to amplification. the detection limit of the rt-lamp assay was approximately 10(2) eid(50/50 μl) tcov genome, and no cross-reaction with other avian viruses was observed. the assay was evaluated further ...201020732411
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