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Results for “Transmissible gastroenteritis”

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PubMed1984

Replication of transmissible gastroenteritis coronavirus (TGEV) in swine alveolar macrophages.

Several strains of the enteropathogenic coronavirus transmissible gastroenteritis virus (TGEV) have been shown to replicate in alveolar macrophages maintained in vitro. A distinct cytopathic effect was observed at a multiplicity of infection greater than or equal to 0.1. Infected cells released infectious virus. The extent of both virus production and cell destruction was highly dependent upon the virus input. At low input, cell viability was affected only slightly, and a delayed and persistent virus production could be observed. TGEV infection of macrophages also led to a marked synthesis of type I interferon. Thus, the possibility that alveolar macrophages act as an extra-intestinal target for TGEV must be considered.

Animals↗

PubMed1991

A capture-enzyme immunoassay for rapid diagnosis of transmissible gastroenteritis virus.

Two enzyme immunoassays (EIA) were developed for the detection of swine transmissible gastroenteritis virus (TGEV) antigens. The 2 EIAs used the same detecting system, a monoclonal antibody conjugated to horseradish peroxidase, but used different capture systems including a monoclonal antibody (m-EIA) or a polyclonal antibody (p-EIA). The EIAs were compared with the fluorescent antibody test (FAT) and electron microscopy (EM) for the detection of TGEV in intestinal samples of experimentally inoculated gnotobiotic piglets and of conventional diarrheic pigs submitted for diagnosis. In the gnotobiotic piglets experimentally inoculated with TGEV, 81.8% (9/11) were positive for TGEV by p-EIA, and 72.7% (8/11) were positive by m-EIA. In comparison, 81.8% (9/11) were positive by FAT and 27.2% (3/11) were positive by EM. Three noninfected controls were negative by all tests. In the diagnostic samples, 86.0% (43/50) were positive by p-EIA, 68.2% (30/44) were positive by m-EIA, 28.6% (14/49) were positive by IFA, and 38.0% (19/50) were positive by EM. The m-EIA had a higher agreement with FAT and EM than did p-EIA.

Animals↗

PubMed2001

A serodiagnostic ELISA using recombinant antigen of swine transmissible gastroenteritis virus nucleoprotein.

A serodiagnostic ELISA utilizing the recombinant nucleoprotein (rN protein) of transmissible gastroenteritis virus (TGEV) was developed, and evaluated by examining a panel of 141 virus neutralization (VN) positive and 101 negative sera. The rN protein-based ELISA (rnELISA) appeared to be highly sensitive and specific (98.6% and 98.0%, respectively) when it was compared to the VN test. The result was similar to that of an ELISA based on purified viral antigens with showing good correlation (R=0.829). No cross-reaction was detected with antisera against porcine epidemic diarrhea virus, hog cholera virus, type A rotavirus, pseudorabies virus and swine vesicular disease virus in this ELISA. The rnELISA can be an alternative for the diagnosis of TGE with a great advantage in antigen preparation.

Animals↗

PubMed1989

Lesions of transmissible gastroenteritis virus infection in experimentally inoculated pigs suckling immunized sows.

Intestinal lesions of transmissible gastroenteritis (TGE) virus infection in conventionally reared pigs suckling either nonvaccinated, vaccinated, or previously infected sows were studied by scanning electron microscopy, light microscopy, and immunofluorescent microscopy for TGE viral antigen. Pigs were inoculated with virulent TGE virus when they were 5 or 21 days old and were euthanatized shortly after the onset of diarrhea or 96 hours after inoculation if no diarrhea developed. Pigs inoculated when they were either 5 or 21 days old and suckling nonvaccinated sows developed severe lesions, including swelling and necrosis of enterocytes and severe villus atrophy. Pigs inoculated when they were 5 days old and suckling sows vaccinated with attenuated vaccines developed less-severe villus atrophy, and those suckling sows immunized by exposure to nonattenuated TGE virus developed moderate or no villus atrophy. Pigs inoculated when they were 21 days old and suckling sows vaccinated with attenuated vaccines had severe villus atrophy, whereas those suckling sows immunized by exposure to nonattenuated virus had more-moderate villus lesions. Villus atrophy was inhibited to various degrees in pigs suckling immunized sows, depending in part on the antibody titer in the colostrum and milk.

Animals↗

PubMed1980

Characterization of immunoglobulin A antibody in serum of swine inoculated with transmissible gastroenteritis virus.

Sera and contents of the small intestine from swine inoculated with transmissible gastroenteritis (TGE) virus were examined for immunoglobulin (Ig) A antibody responses by the radioimmunoprecipitation test with antiporcine IgA serum. When swine were orally inoculated with virulent virus, IgA antibody activity was detected in the contents of the small intestine and in serum from postinoculation days 7 to 56. However, IgA antibody activity was not detected in the contents of the small intestine or serum in swine inoculated IM with attenuated virus. The Ig class of serum of swine inoculated with TGE virus was examined by gel filtration chromatography. When swine were orally inoculated with virulent virus, neutralizing antibody was always detected from both fractions of IgA and IgG Neutralizing antibody ws detected only from the IgG fraction in the serum of swine inoculated IM with attenuated virus. The molecular size of serum IgA antibody was determined by sucrose density gradient centrifugation. The titer of this antibody was the highest at a position between 10.9S- and 7S-marker protein. The antibody consisted almost exclusively of dimers. It appeared that serum IgA antibody always originated from the lymphoid tissue of the intestinal tract. This antibody was regarded as an indicator of active immunity of TGE virus.

Animals↗

PubMed1996

Elimination of transmissible gastroenteritis virus from a pig farm by culling and serological surveillance.

The first and only outbreak of transmissible gastroenteritis in pigs in Ireland occurred in 1984 in a 650-sow unit which was one of three such units owned by one enterprise which supplied pigs to a 12,000 head fattening unit in the same ownership. The depopulation of the clinically infected unit and extensive serological monitoring of pigs in the other units and in pig farms throughout the country has proved successful in the elimination of transmissible gastroenteritis infections from pigs in Ireland.

Animals↗

PubMed1984

Hypoglycemia: a factor associated with low survival rate of neonatal piglets infected with transmissible gastroenteritis virus.

The main purpose of this work was to study changes in the balance of fluids, electrolytes and blood metabolites in neonatal piglets with severe transmissible gastroenteritis. Six two day old conventional piglets were infected with transmissible gastroenteritis virus while six others were used as normal controls. Blood samples were collected in heparin when the infected piglets were moribund. The following variables were measured: packed red cell volume, total plasma protein and bicarbonate, blood pH, blood urea nitrogen and plasma glucose, creatinine, chloride, inorganic phosphorus, sodium, potassium, magnesium and calcium. Vomiting and diarrhea appeared 12 to 24 hours postinoculation in the infected piglets and they were moribund one or two days later. Before becoming moribund, most of the piglets fell rapidly into a lethargic and comatose state. The most evident changes in their blood variables were an increase in packed cell volume, total protein, blood urea nitrogen, phosphorus and magnesium levels and a decrease in pH and bicarbonate concentration as well as a severe hypoglycemia. The results suggest that severe hypoglycemia coupled with metabolic acidosis and dehydration might be an important factor contributing to the high mortality rates caused by transmissible gastroenteritis in neonatal piglets. The hypoglycemia results from a combination of the inadequate glucose metabolism inherent to neonatal piglets and the acute maldigestion and malabsorption resulting from the diffuse and severe villous atrophy induced by the virus.

Animals↗

PubMed1972

Antibody responses in serum, colostrum, and milk of swine after infection or vaccination with transmissible gastroenteritis virus.

The antibody response of pregnant swine to transmissible gastroenteritis (TGE) virus was studied, with special reference to the titers and the immunoglobulin (Ig) class of TGE neutralizing antibodies in colostrum and milk. Animals vaccinated twice intramuscularly or intramammarily with live attenuated TGE virus developed high levels of antibodies in serum and colostrum, but the levels in milk declined markedly within a few days post-farrowing. In contrast, animals naturally or experimentally infected with virulent virus generally developed lower levels of antibodies in serum and colostrum but maintained higher levels in milk, as compared to the vaccinated animals. Gel filtration studies indicated that antibodies in milk from vaccinated animals were primarily of the IgG class, whereas those from the naturally or experimentally infected animals were primarily of the IgA class. The ability of sows to transmit a high degree of passive immunity to their suckling progeny was more closely associated with TGE antibodies of the IgA than the IgG class. Present evidence suggests that high levels of TGE antibodies of the IgA class occur in milk as a result of an infection of the intestinal tract. Probable reasons for this are discussed.

Animals↗

PubMedDate not supplied

Transmissible gastroenteritis coronavirus: surface antigens induced by virulent and attenuated strains.

Three strains of the transmissible gastroenteritis virus (TGEV) possessing different degrees of pathogenicity for piglets were examined for their capacity to express M and S glycoproteins on the infected cell surface using a microwell immunoperoxidase test. These two viral glycoproteins were easily detected on the plasma membrane of 0.1% paraformaldehyde-fixed swine testis (ST) or pig kidney (RP.D) cells which were infected with high-passaged Purdue-115 and low-passaged D-52 strains and a high-passaged attenuated (188-SG) mutant of TGEV. No significant differences were found between attenuated and virulent strains with regard to the viral antigen expression on the membrane of infected cells over a 14-h period.

Animals↗

PubMed1986

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 gnotobiotic pigs in isolation remains subclinical. The infection, either experimental or in the field, results in the formation of antibodies which neutralise the classical enteric TGEV. Based on this relationship, this virus is assumed to be a new TGEV-related porcine respiratory coronavirus or TGEV itself which has totally lost its tropism for the enteric tract.

Animals↗

PubMed1991

Infection of pigs with transmissible gastroenteritis virus from contaminated carcases.

Sixteen 6-month-old pigs were exposed to transmissible gastroenteritis (TGE) virus by placing them in close contact with piglets infected at 1 week of age. Fourteen of the older pigs were slaughtered between 1 and 5 d after exposure to infection and their carcases dressed in simulated abattoir conditions. Samples of muscle, bone marrow and carcase lymph nodes were stored at -25 degrees C for at least 30 d and then homogenised and fed to groups of 1-week-old and 3-week-old pigs. Four of 12 one-week-old pigs died and TGE virus was isolated from intestinal contents of one of these. All pigs of both age groups developed neutralising antibody to TGE virus over the ensuing 4 w. The results indicate that carcases from pigs infected with TGE virus can represent a source of infection for susceptible pigs given access to them.

Abattoirs↗

PubMed1976

Partial characterization of the principal soluble antigens associated with the coronavirus of transmissible gastroenteritis by complement fixation and immunodiffusion.

A microtiter complement fixation (CF) test to detect transmissible gastroenteritis (TGE) viral antigen was developed, using TGE hyperimmune pig serum as an antibody source. Sera from TGE covalescent pigs did not fix complement by this test. Maximal virus and soluble antigen (SA) titers were obtained 36 to 48 h after inoculation of swine testes cells. Cell-associated virus and SA titers were higher than those in the culture fluid, which had to be concentrated 20X before use as antigen in agar immunodiffusion tests (ID). By sucrose density-gradient centrifugation, the SA had a buoyant density of 1.10 g/ml and could be separated from the virus that banded in the 1.19-g/ml region. Virus and SA from three different isolates of TGE had the same buoyant densities. Heating and proteolytic enzyme digestion established the protein nature of the SA. As assayed by CF and ID, there were stability differences between crude and purified preparations of SA. Antibody prepared in rabbits against the SA neutralized the TGE virus.

Animals↗

PubMed1991

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 sampled in 1990 were seropositive to TGEV. Seroconversion to the virus neutralisation test occurred in a closed herd in 1984, with no apparent spread, but later testing by the ELISA did not detect any blocking antibodies. The possibility of the existence of a less contagious strain of PRCV is discussed. All British isolates of TGEV tested by the indirect fluorescent antibody test were recognised by the monoclonal antibody 1D.B12, the indicator antibody in the ELISA.

Animals↗

PubMed2000

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 serum retrospectively after disease outbreaks. A reverse transcription (RT)-nested polymerase chain reaction (PCR) with primers targeted to the S gene deletion region to differentiate TGEV/PRCV was developed. The specificity of the RT-nested PCR was confirmed with reference and recent field strains of TGEV/PRCV, and its sensitivity was analyzed by testing nasal and fecal samples collected from pigs at various days postinoculation (DPI) with TGEV or PRCV. Specific PCR products for TGEV/PRCV were detected only with the homologous reference or field coronaviruses and for 10-14 DPI of pigs with TGEV (feces) or PRCV (nasal samples). The RT-nested PCR assay was more sensitive than antigen-based assays on the basis of duration of virus detection in experimentally infected pigs and was directly applicable to nasal as well as fecal specimens from the field.

Animals↗

PubMed1985

[Trials of peroral vaccination of newborn pigs against transmissible gastroenteritis (TGE)].

Experiments were carried out to apply oral vaccination to newborn pigs against transmissive gastroenteritis on a stationary swine breeding complex at the time when the disease assumed an acute course and on newly infected farms. Used was an attenuated strain an hour prior to allowing the pig to suck. It was found that such vaccination approach was innocuous. It proved effective when applied at the moment of birth both on the infected (stationary) farms and in the new foci of infection--morbidity and mortality were lowered and the body development of pigs was improved. Such vaccination was shown to produce also an antiepizootic effect if systematically used on stationary farms--clinically, there were no new epizootic outbreaks of the diseases.

Administration, Oral↗

PubMed1993

Comparative study of different immunoserological techniques for the detection of antibodies against transmissible gastroenteritis (TGE) coronavirus.

In order to carry out a sero-epidemiological survey of transmissible gastroenteritis (TGE) infection in a high-density pig-breeding area the Murcia region, Spain), the sensitivity and the specificity of 5 different techniques were compared. Twenty-four sera from non-infected and infected pigs were analyzed by the following tests: in vitro neutralization, indirect ELISA with concentrated virus, indirect ELISA with purified virus, immunocapture ELISA and VELCIA (virus-enzyme linked cell immunoassay). All sera from infected pigs were detected as positive only by seroneutralization, ELISA with purified virus and VELCIA (sensitivity 100%). False-positive sera were detected with several tests (ELISA with purified virus and concentrated virus, ELISA immunocapture with a specificity of 88, 88 and 76% respectively). Only VELCIA provided a specificity as high as that obtained with seroneutralization (100%).

Animals↗

PubMed1985

[Isolation of the transmissible gastroenteritis virus in a continuous pig embryo kidney cell line].

Attempts were made to isolate the virus of transmissive gastroenteritis in a permanent cell line SPEV in view of the diagnostics of the disease. Used were small intestines of pigs during the first 24 hours after the setting in of clinical symptoms. The successful isolation of the virus in a SPEV line depended on the methods employed to handle the material as well as on the ways of inoculating the cell cultures. In the conditions of the investigation most proper proved centrifugation of the organ suspensions and the suspension method of infection. The SPEV line, however, was shown to be insufficiently sensitive to isolate the virus of transmissive gastroenteritis. About 30 per cent only of the positive material could be used to demonstrate the virus following direct infection, while the study of the remaining (up to 62 per cent) material required additional passing. The SPEV line could replicate the virus after its infection with organ suspensions containing the virus, and this could be demonstrated through immunofluorescence investigations. The same method could likewise be employed in the express diagnosing of the disease. The passing of the virus strains in the SPEV line led to their attenuation. In order to retain the virulence of the strains passing should take place in nonimmune pigs or should alternate with the use of both pigs and cell cultures.

Animals↗

PubMed1984

The effect of adoptive transfer of mononuclear leukocytes from an adult donor on spontaneous cell-mediated cytotoxicity and resistance to transmissible gastroenteritis in neonatal piglets.

The purpose of this study was to attempt to establish spontaneous cell-mediated cytotoxicity effector activity in the intraepithelial lymphocytes of neonatal piglets by adoptive transfer of mononuclear leukocytes from an adult donor and to determine the effect of transfer on the resistance of piglets to transmissible gastroenteritis. Cytotoxicity was determined by a chromium release assay using PK-15 cells persistently infected with transmissible gastroenteritis virus as targets. The experimental animals were inbred miniature pigs, in which a high degree of uniformity in lymphocyte defined histocompatibility complex antigens was demonstrated by the mixed lymphocyte reaction. Adoptive transfer of 8 X 10(7)-4 X 10(8) adult pig leukocytes established effector activity in eight recipient piglets, and leukocytes labelled with fluorescein isothiocyanate homed to the epithelium of the small intestine. When four recipients of 5 X 10(8) adult leukocytes were challenged with transmissible gastroenteritis virus, the onset of diarrhea was delayed for 24 h and the diarrhea was usually milder than in four untreated control piglets. It was concluded that the adoptive transfer of leukocytes with spontaneous cell-mediated cytotoxicity effector activity, which homed to the small intestinal epithelium, may have contributed to an increased resistance to transmissible gastroenteritis.

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