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1.
Clinical, immunofluorescence and histopathological observations were found to be an efficient approach for the confirmation of the diagnosis of transmissible gastroenteritis in feeder swine. Two cases are reported to exemplify how feeder swine exposed to points of concentration such as holding areas, sales barns and auctions can play an important role in the epizootiology of transmissible gastroenteritis. A third field case is reported as an example of an outbreak of transmissible gastroenteritis beginning in feeder swine and then spreading to baby pigs on the farm. All baby pigs died that were born during the acute phase of the outbreak in the feeder swine. Baby pigs born shortly after the clinical signs had abated in the herd, and from sows that had been exposed orally to virulent transmissible gastroenteritis virus and vaccinated with a commercial transmissible gastroenteritis vaccine ten days before farrowing, survived. This was explained by a combination of a decrease in the amount of virus shed in the environment and the immunity induced in the sows. These observations of field outbreaks of transmissible gastroenteritis combined with recently reported experimental studies lend strong support to the hypothesis of a reservoir for transmissible gastroenteritis virus in feeder pigs. This reservoir would be based principally on the transmission of the virus on a continuous basis from the feces of recently infected pigs to susceptible pigs. Clinical signs of transmissible gastroenteritis in such pigs are difficult to recognize or absent and this contributes to the importance of the reservoir in the field.  相似文献   

2.
Swine exposed to attenuated transmissible gastroenteritis virus had higher virus-neutralizing antibody titers than did swine exposed to virulent virus. The cellular response, measured by the direct leukocyte migration-inhibition (LMI) procedure, was greater in swine exposed to virulent virus than in swine exposed to the attenuated virus. Leukocytes from exposed swine were inhibited more in the LMI procedure in the presence of the homologeous sensitizing antigen than in the presence of the heterologous viral antigen. The humoral response measured by virus neutralizing reached a peak 21 days after exposure, and the cellular response measured by LMI reached a peak 28 days after exposure.  相似文献   

3.
Swine exposed to transmissible gastroenteritis viral antigens developed humoral and cell-mediated immunity. Migration of leukocytes from exposed swine was inhibited in the presence of the sensitizing antigens, whereas migration of leukocytes from nonexposed swine was not inhibited in the presense of these same antigens. In virus-neutralization-positive animals, it was not possible to correlate degree of inhibition with virus-neutralization titer. Inhibition was observed 7 days after exposure and was found to persist for at least 35 days.  相似文献   

4.
A continuous line of swine testes cell culture monolayers was infected at various ages with both cell culture-adapted transmissible gastroenteritis (TGE) virus and tissue infected with TGE virus. Both produced increasing numbers of plaques as the cell monolayers aged from two to five days. Therefore, allowing the swine testes cell monolayer to age five to six days before inoculation should increase the likelihood of detecting TGE virus by plaque assay.  相似文献   

5.
The protective effect of sera produced in swine and goats exposed to virulent transmissible gastroenteritis virus (TGEV) or modified-live TGEV was tested in hysterectomy-derived, colostrum-deprived three-day-old pigs. Pigs were given serum with their daily ration of milk, and their immunity to virulent TGEV was determined. The pigs were observed for ten days for clinical signs of TGEV infection. One of nine pigs receiving goat serum was protected whereas all three pigs receiving three doses of swine serum per day were protected. Because virus was not isolated from the goats after oral/intranasal vaccination, it is suggested the virus did not replicate in either the respiratory or digestive tract of the goat.  相似文献   

6.
An enzyme-linked immunosorbent assay (ELISA) was developed for detection and quantification of serum antibodies to transmissible gastroenteritis virus (TGEV) in swine. Sera from pigs inoculated with cell culture-origin TGEV or gut-origin TGEV were tested for anti-TGEV antibody by ELISA and by serum virus-neutralization test (NT). The ELISA detected antibody 3 days (av) sooner than did the NT when sera from pigs inoculated with cell culture-origin TGEV were tested and 1 day sooner than did the NT when sera from pigs inoculated with gut-origin TGEV were tested. The ELISA appeared to be more sensitive than the NT, since ELISA was more responsive to low-level antibody and ELISA titers exceeded NT titers.  相似文献   

7.
Nine of 11 six-to-eight-week-old beagle puppies from a colony started from hysterectomy-derived breeding stock developed a serological response to a transmissible gastroenteritis (TGE)-associated virus following exposure to TGE-infected pig intestinal tissue. The virus was not isolated on swine testis (ST) cells from dog rectal swabs, except in one instance; however, when composites of rectal swabs from all 11 dogs taken seven days and fourteen days postexposure were fed to piglets, they developed signs of TGE and died within seven days. This TGE-associated virus was readily isolated on ST cells from the rectal swabs of the exposed piglets.  相似文献   

8.
Serologic virus neutralization tests, indirect immunofluorescence tests, and ELISA, using tissue culture-adapted feline infectious peritonitis virus (FIPV) or feline enteric coronavirus (FECV) were compared for their ability to distinguish specific virus exposure in cats. Sera of specific-pathogen-free cats inoculated with virulent or modified FIPV or FECV were used to compare the sensitivity and specificity of the homologous assays to a heterologous assay that measures antibody reactivity with transmissible gastroenteritis virus of swine. The geometric means of the serologic titers in FIPV and FECV assays were higher for FIPV- or FECV-infected specific-pathogen-free cats than the geometric means of the transmissible gastroenteritis virus assays for most groups. None of the assays was specific enough to discern the virus to which a cat had been exposed. However, the FIPV virus neutralization test appeared to be more sensitive for detection of an early response to FIPV infection than did the FIPV immunofluorescence test or FIPV-ELISA.  相似文献   

9.
Precipitating antibodies against transmissible gastroenteritis viral antigens were detected by the immunodiffusion test in two transmissible gastroenteritis viral hyperimmune antisera and in antiserum prepared against haemagglutinating encephalomyelitis virus but not in sera from several species of normal animals, in antisera prepared against a variety of othet viruses and bacteria or sera from swine with bacterial enteritis. When the immunodiffusion test was compared with the virus neutralization test for the detection of transmissible gastroeneritis viral antibodies in 20 swine sera certain samples which contained high titres of virus neutralizing antibodies failed to produce precipitation while other sera were positive in the immunodiffusion test although their virus neutralizing antibody titres were relatively low. Precipitating antibodies were also detected by immunodiffusion in several samples of milk whey from a sow which had been vaccinated with inactivated transmissible gastroenteritis virus.  相似文献   

10.
Two virus isolates from transmissible gastroenteritis (TGE) of swine were adapted to grow in primary swine kidney cells. Growth of the virus was indicated by the resistance of the infected cells to the cytopathic effect of a virus diarrhea virus of cattle, and by the development of large round cells on the cell sheet.

Evidence that these virus isolates were TGE was obtained by the development of signs of the disease followed by death of exposed SPF pigs, or the resistance of the recovered pigs to further signs of disease when they were exposed to virulent TGE contained in virus bearing intestinal tissue.

The in vitro and in vivo serum neutralization tests, along with staining of infected cells by fluorescein conjugated TGE antiserum, gave further indication of the specific nature of the virus growing in the cell cultures.

  相似文献   

11.
应用RT-PCR方法扩增了猪传染性胃肠炎病毒(TGEV)TH-98株S基因5′端含有B、C抗原位点的片段。将该片段亚克隆至杆状病毒转移载体pMelBac B中。重组质粒经纯化,与线性化的杆状病毒共转染Sf9昆虫细胞,经4轮蚀斑筛选,获得了纯化的重组病毒,最终实现了在昆虫细胞内的蛋白表达。经Dot-ELISA进行抗原性分析,结果表明重组蛋白具有抗原性。本研究猪传染性胃肠炎血清学诊断方法的建立提供了必要的物质基础。  相似文献   

12.
Eighteen seronegative swine weighing from 9 to 11 kg were exposed intranasally with the Shope strain of pseudorabies virus (PRV) and were observed for 21 days in an experiment to detect virus shedding and immune responses. All swine had PRV in their nasal passages at 7 days after exposure; they also had precipitating antibodies to PRV as determined by the microimmunodiffusion test (MIDT) and very low levels of virus-neutralizing (VN) antibodies. The PRV was isolated from only 2 swine at postexposure day 14; all swine were MIDT positive, and VN titers ranged from 4 to 128. Virus was not isolated from the swine at 21 days after exposure, but all were MIDT positive; VN titers ranged between 8 and greater than or equal to 256.  相似文献   

13.
This study identifies the in vitro differences (markers) between virulent and attenuated transmissible gastroenteritis (TGE) viruses. Exposure of virulent Miller strain and attenuated Purdue strain TGE viruses to a spectrum of acidities indicated that the Miller strain was more stable at pH 2. Acidities at or above pH 3 did not reduce viral infectivity of either strain. When virulent and attenuated viruses were exposed to gastric fluids of either fed or fasted swine, there was a similar degree of sensitivity. Carboxypeptidase B, alpha-amylase, and alkaline phosphatase present in porcine small intestinal fluids did not cause a significant difference in sensitivity between virulent and attenuated virus isolates. The digestive enzymes: trypsin, alpha-chymotrypsin, pancreatin, peptidase, and carboxypeptidase A did not (or only slightly) inactivate virulent Miller strain TGE virus, but greatly reduced infectivity of attenuated viruses (Purdue strain and TGE vaccine virus isolates). The attenuated strains were significantly more sensitive to small intestinal fluids from both fasted and fed adult swine. Differential sensitivities between virulent and attenuated TGE viruses to digestive fluids from stomach and small intestine further substantiate the notion of differential susceptibility to small intestinal proteases as a correlate of viral virulence.  相似文献   

14.
The interferon sensitivity of selected porcine viruses.   总被引：7，自引：0，他引：7       下载免费PDF全文
The objective of this study was to compare the sensitivity of 11 porcine viruses to the antiviral effects of porcine interferon-alpha in serum from piglets which had been infected 19 h previously with transmissible gastroenteritis virus, and of porcine interferon-beta prepared in PK-15 cells by induction with polyinosinic:polycytidylic acid, in yield reduction assays in pig kidney cells which were treated with interferon before virus challenge, and both before and after virus challenge. The most sensitive virus to both types of interferon was vesicular stomatitis. A porcine isolate of bovine herpesvirus type 1, hemagglutinating encephalomyelitis virus and porcine enterovirus types 1 and 2 were also highly sensitive to interferon-alpha. There was little reduction in the yield of porcine parvovirus or porcine rotavirus, while swinepox, swine influenza and transmissible gastroenteritis viruses were intermediate in their sensitivity to interferon-alpha. In addition to vesicular stomatitis virus, porcine adenovirus type 3, swine influenza, hemagglutinating encephalomyelitis and porcine rotavirus were highly sensitive to interferon-beta, while swinepox, bovine herpesvirus type 1, porcine parvovirus, transmissible gastroenteritis and porcine enteroviruses were less sensitive than the above viruses to interferon-beta, although all showed significant reductions in virus yield.  相似文献   

15.
A bovine viral diarrhea virus (BVDV-C) was isolated from swine tissue culture cells used to attenuate the transmissible gastroenteritis virus (TGEV) after 68 passes. Piglets given a pure culture of BVDV-C developed clinical signs similar to those of a mild TGEV infection and recovered by 10 days postexposure. Villous blunting and fusion was observed in the small intestine, and a lymphocyte depletion was observed in Peyer's patches in the ileum. Piglets given a combination of BVDV-C and attenuated TGEV developed clinical signs similar to those of a virulent TGEV infection and were euthanized. The combined infection induced a generalized lymphocyte depletion throughout the lymphatic system and villous atrophy in the intestinal tract. Piglets exposed to a another type I strain of BVDV (NY-1) either alone or in combination with the attenuated TGEV had mild clinical signs similar to those of a TGEV infection. Moderate villous atrophy in the ileum and a lymphocyte depletion in the mesenteric lymph node were observed in these piglets postmortem. The data indicate a potential problem for diagnostic laboratories in relation to a diagnosis of virulent TGEV infections and in the field for young piglets exposed to a BVDV-contaminated TGEV vaccine.  相似文献   

16.
Virus-neutralizing antibody and immunity after infection with foot-and-mouth disease virus was studied for 128 days in a group of swine. Antibody first appeared at 3 days, rose to peak levels between 7-10 days, and regressed to a plateau by 28 days. After 28 days, there was little change in mean antibody titres.

An attempt to reinfect 10 swine at 28 days was not successful. At 128 days, the immune status of 4 convalescent swine neutralized more than 4 logarithms of virus in an in vivo titration. However, in another group of 5 convalescent swine, one developed vesicular lesions when exposed to infected swine.

Efforts to demonstrate latent virus in one pig 128 days after infection were not successful.

  相似文献   

17.
Clinical signs of transmissible gastroenteritis were not observed in newborn pigs orally inoculated with the high-passaged vaccinal transmissible gastroenteritis virus (TO-163 strain). Vaccinal viral multiplication in digestive tract of newborn pigs fed colostrum before inoculation and kept at 21 to 22 C was diminished, but was not diminished in those fed colostrum and kept at 10 to 11 C. Other groups of newborn pigs inoculated with the attenuated vaccinal virus and kept at 18 to 22 C or at 31 to 34 C were challenge exposed with virulent intestinal virus on the 1st, 2nd, . . ., or 6th postinoculation (PI) days. In the groups kept at 18 to 22 C, 2 of 7 inoculated pigs challenge exposed with virulent virus on the 3rd PI day, 4 of 7 pigs exposed on the 4th PI day, and all of the pigs exposed on and after the 5th PI day survived the exposure. In the groups kept at 18 to 22 C, the attenuated vaccinal virus was distributed mainly in the respiratory organs and lymphatic tissues. On the contrary, in the groups kept at 31 to 34 C, all of the pigs died in 2 to 5 days after challenge exposure, and the attenuated vaccinal virus was scarcely detected in any of the pigs.  相似文献   

18.
Butylated hydroxytoluene (BHT) was evaluated for antiviral effectiveness on pseudorabies virus (PRV) in cell culture, mice, and swine. When relatively small amounts of BHT were mixed with PRV and incubated at 37 C for 30 or 60 minutes before inoculation into cell cultures, the cell cultures did not become infected with virus. The PRV was not infectious when the virus was treated with BHT and then inoculated intraperitoneally into mice, but was infectious when BHT and PRV were inoculated simultaneously or when BHT was inoculated either 30 or 60 minutes before PRV. Swine fed BHT-medicated feed for 10 days before they were intranasally exposed with virulent PRV did not have overt signs of pseudorabies, had a lower concentration of PRV in nasal mucus than did control swine, and had acceptable blood enzyme and cholesterol concentrations during the experiment. The BHT was detected in tissues of 2 swine after they were fed BHT-medicated feed for 10 days, and higher concentrations of BHT were detected in tissues of 3 swine given BHT feed for 29 days.  相似文献   

19.
A serological survey of selected pathogens in wild boar in Slovenia   总被引：6，自引：0，他引：6  
Serum samples collected from 178 shot wild boars (Sus scrofa) were tested for the presence of antibodies against classical swine fever virus, Aujeszky's disease virus (ADV), porcine reproductive and respiratory syndrome virus, porcine respiratory coronavirus (PRCV), transmissible gastroenteritis virus, swine influenza virus, porcine parvovirus (PPV), swine vesicular disease virus, Actinobacillus pleuropneumoniae (APP), Mycoplasma hyopneumoniae, Salmonella spp., Brucella spp. and Haemophilus parasuis (HPS) throughout Slovenia during the hunting season 2003/2004. The number of samples corresponds to 3% of the total hunting bag. By enzyme-linked immunosorbent assay (ELISA) antibodies against ADV were detected in 55 sera (31%), against PRCV in five sera (3%), PPV in 87 sera (49%), APP in 93 sera (52%), M. hyopneumoniae in 38 sera (21%), Salmonella spp. in 85 sera (47%) and HPS in 33 sera (18%).  相似文献   

20.
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.  相似文献   

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