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Results for “Transmissible gastroenteritis”

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PubMed2000

Characterization of the sialic acid binding activity of transmissible gastroenteritis coronavirus by analysis of haemagglutination-deficient mutants.

Transmissible gastroenteritis coronavirus (TGEV) agglutinates erythrocytes of several species by virtue of sialic acid binding activity of the surface protein S. We have isolated and characterized five haemagglutination-defective (HAD) mutants. In contrast to the parental virus, the mutants were unable to bind to porcine submandibulary mucin, a substrate rich in sialic acid. Each of the mutants was found to contain a single point mutation in the S protein (Cys155Phe, Met195Val, Arg196Ser, Asp208Asn or Leu209Pro), indicating that these amino acids are affecting the sialic acid binding site. In four of the HAD mutants a nearby antigenic site is affected in addition to the sialic acid binding site, as indicated by reactivity with monoclonal antibodies. The parental virus was found to have an increased resistance to the detergent octylglucoside compared to the HAD mutants. This effect depended on cellular sialoglycoconjugates bound to the virion. If the binding of sialylated macromolecules was prevented by neuraminidase treatment, the parental virus was as sensitive to octylglucoside as were the HAD mutants. We discuss the possibility that the sialic acid binding activity helps TGEV to resist detergent-like substances encountered during the gastrointestinal passage and thus facilitates the infection of the intestinal epithelium. An alternative function of the sialic acid binding activity - accessory binding to intestinal tissues - is also discussed.

Animals↗

PubMed1988

Cell-mediated immune responses of suckling pigs inoculated with attenuated or virulent transmissible gastroenteritis virus.

Two litters of suckling pigs seronegative for transmissible gastroenteritis (TGE) virus were orally inoculated with live attenuated (P115) or virulent (M5C) strains of TGE virus. A third seronegative litter (controls) was given cell culture fluids from uninfected cells. Lymphocytes were collected from blood, spleen, mesenteric lymph nodes, and Peyer patches of euthanatized pigs at 0 day and approximately weekly until 26 days after exposure and at approximately 45 days after exposure. Sera were tested for virus-neutralizing antibody titers by use of plaque reduction. Lymphocytes were tested in a lymphocyte proliferation assay for uptake of [3H]thymidine after incubation with the homologous or the heterologous strain of inactivated TGE virus or uninfected cell culture fluids. Only pigs inoculated with virulent TGE virus developed clinical signs of TGE and shed virus. However, all pigs inoculated with TGE virus seroconverted at 6 days after exposure. Responses of lymphocytes from all sources from TGE virus-inoculated pigs peaked between 6 and 14 days after exposure. Pigs inoculated with virulent TGE virus had higher lymphocyte proliferative responses and neutralizing antibody titers than did pigs inoculated with attenuated TGE virus. Cessation of virus shedding coincided with the peak of lymphocyte proliferative responses. The highest responses were with intestinal lymphocytes (mesenteric lymph nodes and Peyer patches) from pigs inoculated with virulent TGE virus. The responses of intestinal lymphocytes from pigs inoculated with attenuated virus were not significantly different from those of pigs inoculated with cell culture fluid. Lymphocytes collected from all sources, except blood from M5C-inoculated pigs, had significantly (P less than 0.05) higher responses to the homologous than to the heterologous TGE virus stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1980

Mild transmissible gastroenteritis in pigs suckling vaccinated sows.

A strain of transmissible gastroenteritis (TGE) virus of low virulence was isolated from 14-day-old pigs suckling sows vaccinated with an attenuated TGE vaccine. Diarrhea developed in suckling pigs approximately 14 days after farrowing in 4 farrowings; however, none of these pigs died from diarrhea. Diarrhea ceased after the 4th farrowing, when vaccination of sows was discontinued. Experimentally, both the field isolate and the vaccine strain were infective and in some instances lethal for 2-day-old pigs exposed orally; however, neither strain was as virulent as the Purdue strain.

Animal Population Groups↗

PubMed1976

Transmissible gastroenteritis virus: plaques and a plaque neutralization test.

A plaquing system and plaque neutralization test in porcine thyroid cells were used to study different transmissible gastroenteritis isolates and hemagglutinating encephalomyelitis virus. Among transmissible gastroenteritis virus isolates, plaque size varied considerably and mixed size ranges sometimes occurred. The most recently isolated viruses produced smaller plaques than the laboratory viruses or hemagglutinating encephalomyelitis virus. All transmissible gastroenteritis virus isolates reacted in the plaque neutralization test with a transmissible gastroenteritis virus antiserum which showed no activity against hemagglutinating encephalomyelitis virus. Plaque neutralization results both from experimentally infected pigs and following a field outbreak demonstrated the reliability of this test and its greater sensitivity than the conventional tube test.

Animals↗

PubMed1976

Intestinal immune response of feeder pigs to infection with transmissible gastroenteritis virus.

Five feeder pigs 4 to 6 months old were orally inoculated with transmissible gastroenteritis virus. Diagnosis of transmissible gastroenteritis was made on the basis of clinical signs and examination of intestinal mucosa by the fluorescent antibody technique. Immunoglobulins were extracted from intestinal fluid of infected feeder pigs. Virus-binding and neutralizing antibodies were detected in intestinal extracts between 7 and 56 days after infection. The concentration of binding antibodies reached a peak at 21 days after infection and was on the decline at the end of the experiment on the 56th postinfection day. In contrast, neutralizing intestinal antibody concentration was increasing on day 56. In both systems, the predominant immunoglobulin was of the IgA class. Examination of blood serums of the pigs by the plaque-reduction technique showed progressive antibody increases ranging in titer from 1:8 on day 7 to 1:256 on day 56 after infection. An analysis of the protein profiles from these serums showed a significant increase in the concentration of gamma-globulins and a decrease in the albumin fraction.

Animals↗

PubMed1978

The use of immunofluorescence techniques for the laboratory diagnosis of transmissible gastroenteritis of swine.

Over a four year period, 74 of 250 field outbreaks of enteric disease (30%) and 110 of 440 swine (25%) were positive for transmissible gastroenteritis by immunofluorescence procedures. Of 141 swine from herds positive for transmissible gastroenteritis 110 (78%) were positive by fluorescent antibody techniques. The fastest, easiest to perform and most effective procedure was the examination of frozen sections of the jejunum from acutely ill animals by the fluorescent antibody tissue section technique. Only two herds were found to be positive by the fluorescent antibody tissue culture technique which were negative by fluorescent antibody tissue section technique. A considerable number of outbreaks, 21 of 74 (28%), of transmissible gastroenteritis were detected by immunofluorescence in swine over two weeks of age. The majority of outbreaks of transmissible gastroenteritis, 50 of 74 (68%), occurred in Missouri during the months of January through April and 63 of 74 (85%) during the months of December through May. The recurrence of the disease in a number of counties over a four-year period suggest the possibility of endemic foci.

Animals↗

PubMed1975

[Economic problems in the control of transmissible gastroenteritis of swine].

The losses ascribable to transmissible gastroenteritis of pigs were financially determined at eight sites with 133-1269 large animal units, as converted to pig stocks. The overall losses were divided as follows: mortality and confiscation - 42.38%, weight gain reduction - 30.50%, extra costs of the enterprise - 13.11%, emergency slaughters 7.79%, and losses in progenies 6.22%. The coefficient of loss per one diseased animal was 42.63 to 114.65 crowns. Furthermore, the level of the assumed losses due to mortality and morbidity prevented by veterinary measures was also calculated. The calculation of the effectiveness of these measures showed that 3.14--60.01 crowns are saved per 1 crown spent. The total number of losses, loss coefficient per one diseased animal, the level of prevented loss, and the money saved per 1 crown were calculated from the over-all societal viewpoint and from the viewpoint of the agricultural enterprise after the detraction of the indemnities from the State Insurance Company.

Abattoirs↗

PubMed2003

Partial sequence of the spike glycoprotein gene of transmissible gastroenteritis viruses isolated in Korea.

The spike (S) glycoprotein of transmissible gastroenteritis virus (TGEV) is the predominant inducer of neutralizing antibodies and has been implicated in virulence and host cell tropism. In this study, the nucleotide and deduced amino acid sequences of the amino terminal half of the S glycoprotein gene of one Korean field TGEV strain (133) isolated in 1997 and three Korean field TGEV strains (KT2, KT3 and KT4) isolated in 2000 and HKT2 strain, KT2 passaged 104 times in ST cells, were determined. The amino terminal half of the S glycoprotein gene including antigenic sites A, B, C and D, were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR). Amplified PCR products were cloned, sequenced, and compared with published sequences for non-Korean TGEV strains. Korea TGEV field strains had 98.5-99.5% nucleotide sequence and 97.2-99.0% amino acid sequence similarity with each other. They had 96.5-99.0% nucleotide sequence similarity and 94.9-97.6% amino acid sequence similarity compared to non-Korean TGEV strains. Korean TGEV strains had several specific nucleotide and amino acid sequences which were not found in foreign TGEV or PRCV strains. HKT2 strain differed by 0.89% in nucleotide and 2.03% amino acid sequences compared to original KT2 strain although the regions forming four antigenic sites were not changed. By phylogenetic tree analysis, Korean field TGEV strains were branched into different groups from non-Korean TGEV or PRCV strains. Korean TGEV field strains KT2 and 133 were branched in separate groups that were differentiated from the other Korean TGEV strains. The Korean TGEV strains seemed to be evolved from a separate lineage of TGEV strain.

Amino Acid Sequence↗

PubMed1978

Intrafetal inoculation of swine with transmissible gastroenteritis virus.

Fetuses in 3 sows were inoculated (intramuscularly) with transmissible gastroenteritis (TGE) virus on 95th, 77th, and 74th days of the gestation. At 15, 14, and 37 days later (or days when pigs were obtained by hysterectomy), there was evidence of intestinal localization of virus, with villous atrophy and subsequent repair. All intrafetal-inoculated pigs became serologic-positive for TGE. A noninoculated pig shown to be seropositive for TGE at 15 days of age (after hysterectomy) was resistant to challenge exposure with virulent TGE virus given on the 32nd day, in contrast to 3 seronegative littermates that developed typical disease when challenge exposed.

Animals↗

PubMed1977

Transmissible gastroenteritis: demonstration of the virus from field specimens by means of cell culture and pig inoculation.

Isolation of transmissible gastroenteritis virus was attempted from segments of jejunum collected from piglets submitted for diagnosis of transmissible gastroenteritis. The virus was isolated more frequently in susceptible piglets than in pig kidney or pig thyroid cells. Practically, both cell systems were equally capable of demonstrating the virus when the tissue suspensions were sonicated. The pig thyroid cells prepared with glands collected from minimal disease pigs were preferred to the pig kidney cells for initial virus isolation because of their ability to respond to transmissible gastroenteritis virus with a progressive cytopathic effect. However, the pig thyroid cells, prepared from pool of glands collected in abattoirs, were often contaminated with parvoviruses and could not be used for diagnostic work. Controlled ultrasound treatments of the inoculum increased the frequency of virus isolation in both cell systems.

Animals↗

PubMedDate not supplied

[Development of test systems of immunoenzyme analysis for the detection of antibodies to the transmissible gastroenteritis virus of swine].

Two variants of enzyme immunoassay (EIA) using purified swine transmissible gastroenteritis virus antigen for sensitization of the solid phase and using infected cells on the solid phase have been developed for quantitation of specific antibodies to swine transmissible gastroenteritis (STG) virus. Both variants of the method were found to have approximately similar sensitivity and to be highly specific. The developed EIA proved to be approximately 100 times as sensitive as neutralization test. The optimal concentration of purified antigen for sensitization of microplates, as well as the multiplicity of infection of the heterologous cell culture grown in microplate wells have been determined. The above methods may be widely used in virological and epizootiological studies.

Animals↗

PubMed2006

Assembly of pseudorabies virus genome-based transfer vehicle carrying major antigen sites of S gene of transmissible gastroenteritis virus: potential perspective for developing live vector vaccines.

Two severe porcine infectious diseases, pseudorabies (PR) and transmissible gastroenteritis (TGE) caused by pseudorabies virus (PRV) and transmissible gastroenteritis virus (TGEV) respectively often result in serious economic loss in animal husbandry worldwide. Vaccination is the important prevention means against both infections. To achieve a PRV genome-based virus live vector, aiming at further TGEV/PRV bivalent vaccine development, a recombinant plasmid pUG was constructed via inserting partial PK and full-length gG genes of PRV strain Bartha K-61 amplified into pUC119 vector. In parallel, another recombinant pHS was generated by introducing a fragment designated S1 encoding the major antigen sites of S gene from TGEV strain TH-98 into a prokaryotic expression vector pP(RO)EX HTc. The SV40 polyA sequence was then inserted into the downstream of S1 fragment of pHS. The continuous region containing S1fragment, SV40 polyA and four single restriction enzyme sites digested from pHS was subcloned into the downstream of gG promoter of pUG. In addition, a LacZ reporter gene was introduced into the universal transfer vector named pUGS-LacZ. Subsequently, a PRV genome-based virus live vector was generated via homologous recombination. The functionally effective vector was purified and partially characterized. Moreover, the potential advantages of this system are discussed.

Animals↗

PubMed1985

[Demonstration of a transmissible gastroenteritis virus by contrast immunofluorescence].

Tested were a number of procedures to employ the immunofluorescence method for diagnosing transmissive gastroenteritis in pigs--impression preparations, frozen cross-sectioned material, and infected cell cultures of the established cell line SPEV. It was found that immunofluorescence microscopy was a dependable method for the express diagnosis of transmissive gastroenteritis. It could be employed in its three variants. The use of impression preparations, however, did not prove as dependable as the remaining ways of applying the method, and this drawback had to be compensated for with the study of a greater number of impression preparations taken from more pigs that had contracted the disease. It was also established that most promising and effective was to apply the method with the use of cell cultures infected with suspensions of organs. Cell cultures of the established SPEV cell line infected with material that contained the virus could produce dependable positive results in immunofluorescence investigations at the 24th hour following inoculation. This method could be employed for the express diagnosis of transmissive gastroenteritis.

Animals↗

PubMed1978

Effects of ambient temperatures on induction of transmissible gastroenteritis in feeder pigs.

Experiments were carried out to investigate the effects of ambient temperatures on the induction of transmissible gastroenteritis in feeder pigs 2 to 3 months old. Pigs maintained at a high temperature (30 +/- 2 degrees C) and exposed to the virulent transmissible gastroenteritis virus did not show clinical signs of the disease during their maintenance at the high temperature. On the other hand, a sudden decrease in the ambient temperature, either before or after virus inoculation, induced severe disease in feeder pigs exposed to the virus. However, continuous maintenance of pigs at the low temperature (4 +/- 1 degrees C) tended to somewhat reduce the frequency of occurrence of signs in proportion to the length of the maintenance periods at that temperature. Pigs raised at temperatures that fluctuated between 20 +/- 2 and 4 +/- 1 degrees C every 24 h developed profuse diarrhea. The duration of clinical signs was longer in pigs maintained under the fluctuating temperatures than in those at the constantly low temperature. With one exception, antibody against transmissible gastroenteritis virus was demonstrated in sera collected from pigs both with and without clinical signs. Antibody titers obtained, however, were somewhat higher in sera collected from pigs that had developed clinical signs than in those from pigs that had endured the infection without showing signs.

Animals↗

PubMed1999

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 variant with an intact spike gene, but a large deletion in ORF 3a. This suggests that ORF 3a is not essential for enteric virulence.

Animals↗

PubMed1993

Antigenic and biological diversity among transmissible gastroenteritis virus isolates of swine.

Twenty-four field isolates of transmissible gastroenteritis virus (TGEV) were isolated and examined for antigenic and biological characteristics. Most TGEV isolates produced a typical cytopathic effect (CPE) in swine testis (ST) cell culture, which included a ballooning or lifting away of the infected cells from the cell monolayer with heavy granulation evident. Minor variations in CPE were observed with one isolate, IA-145. Protein profiles of the TGEV isolates as determined by SDS-PAGE were essentially identical, with the exception of the isolate IA-101. The TGEV isolate IA-101 presented a higher molecular mass M protein and lacked an N protein doublet that was present in all other TGEV isolates. The TGEV isolates were shown to be closely related antigenically by using hyperimmune sera in a virus neutralization (VN) test. Some antigenic diversity was detected by utilizing monoclonal antibodies (mAbs) in a VN test. Titers of the mAbs were highest with the homologous Miller TGEV, and one virus isolate, IA-156, was very poorly neutralized with the mAbs used in this study. Indirect immunofluorescence assay (IFA) results were similar to those obtained by the VN test. These studies show that some biologic and antigenic diversity exists among TGEV isolates.

Animals↗

PubMed2005

Use of monoclonal antibodies in blocking ELISA detection of transmissible gastroenteritis virus in faeces of piglets.

Monoclonal antibodies (mAb) to the transmissible gastroenteritis virus (TGEV) nucleoprotein (N) and membrane protein (M) were prepared and used for the comparative assessment of three blocking ELISA variants to detect TGEV. The competitive blocking ELISA format showed the highest sensitivity, allowing detection of 10(3) TCID50 TGEV/ml in culture medium. Ninety-nine porcine field faecal samples obtained from 37 herds affected with diarrhoea were examined, and various TGEV levels were found in nine samples from six herds. However, only in three samples were significant TGEV concentrations demonstrated. The relationship between incidence of TGEV gastroenteritis and the spread of porcine respiratory coronavirus infection in pig farms is discussed.

Animals↗

PubMed1988

Solid phase immune electron microscopy for diagnosis of transmissible gastroenteritis in pigs.

A serological trapping technique is described for detecting transmissible gastroenteritis (TGE) virus in faeces. The technique involves the coating of electron microscope grids with protein A and specific TGE virus antiserum. Optimal conditions for performing this solid phase immune electron microscopy technique were a concentration 250 micrograms ml-1 of protein A; 1:100 diluted rabbit anti-TGE virus hyperimmune serum for coating the grids and overnight incubation with virus samples. The possibility of detecting coronavirus in crude faeces was highly improved with solid phase immune electron microscopy, compared with conventional negative staining electron microscopy, by specific trapping of virus and prevention of adsorption of contaminants. The sensitivity of the method was evaluated by coded investigation of a dilution series of stock virus mixed with different pools of faeces. The improvement of virus detection in faeces by solid phase immune electron microscopy, compared with standard electron microscopy was at least 100-fold. Faecal shedding of coronavirus by pigs infected with virulent and attenuated strains of TGE virus was studied. Virus detection in faeces by a standard electron microscopy technique was not practical, since the virus was obscured by a large quantity of debris in the faeces. By using solid phase immune electron microscopy, however, the aspect of the specimens on the grids improved so much that, in addition to more common immunofluorescence, the technique might be useful as a diagnostic test for TGE. Virus was detected in daily faecal samples from one or two days after experimental infection with virulent TGE virus, until death in five out of eight animals. Unlike immunofluorescence, solid phase immune electron microscopy may be used for diagnosis in living animals.

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