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At least 955 records · Page 53Linked to original sources
PubMed1996

Comparison of the antigen distribution of two US porcine reproductive and respiratory syndrome virus isolates with that of the Lelystad virus.

One hundred 4-week-old cesarean-derived colostrum-deprived pigs were inoculated with one of two different US porcine reproductive and respiratory syndrome virus (PRRSV) isolates (VR2385, VR2431) or the European Lelystad virus to detect and compare the location and amount of virus antigen. Interstitial pneumonia, myocarditis, lymphadenopathy, and encephalitis were consistently seen in all three groups; however, disease and lesions were more severe in the VR2385 group. Immunohistochemical evaluation of formalin-fixed tissues revealed virus antigen in alveolar macrophages in lungs of 22/25, 14/25, 14/25, and 0/25 of the VR2385, VR2431, Lelystad, and control pigs, respectively. Follicular macrophages and dendritic cells in the lymph nodes of 14/25, 10/25, 10/25, and 0/25 pigs from the VR2385, VR2431, Lelystad, and control groups, respectively, stained positive for virus antigen. Similar cells in the tonsils from 25/25, 21/25, 23/25, and 0/25 pigs from the VR2385, VR2431, Lelystad, and control groups, respectively, stained positive for virus antigen. Other tissues and cells in which virus antigen was detected included macrophages and endothelial cells in the heart, macrophages, and interdigitating cells in the thymus, macrophages and dendritic cells in the spleen and Peyer's patches, and macrophages in hepatic sinusoids, renal medullary interstitium, and adrenal gland. PRRSV persisted in macrophages in the lung, tonsil, lymph node, and spleen for at least 28 days. Significantly more PRRSV antigen was detected in the lung (P < 0.01), lymph nodes (P < or = 0.05), and tonsils (P < 0.05) of the VR2385 pigs than was detected in the same tissues of the VR2431 and Lelystad pigs. The cell types in which PRRSV antigen was detected and the distribution of PRRSV antigen-positive cells within particular tissues and organs were generally similar for the different virus inoculation groups despite differences in virulence of the isolates.

Animals↗
PubMed1989

Evaluation of multivalent Leptospira fluorescent antibody conjugates for general diagnostic use.

Four lots of conjugate were evaluated for optimal dilution and degree of fluorescence produced with reference cultures and bovine and porcine leptospira isolates. One lot that uniformly produced better fluorescence was evaluated for sensitivity and specificity with reference cultures, isolates, culture-positive tissues, and 13 other bacterial species. Further evaluation of the conjugates was done with bovine, porcine, and ovine specimens submitted to a diagnostic laboratory. Leptospires were detected with the fluorescent antibody test (FAT) in 9 of 21 culture-positive bovine kidneys and were detected in diluted cultures when present at concentrations of 10(2)-10(3) organisms/ml. With the exception of Treponema hyodysenteriae, FAT's of other bacterial cultures produced minimal fluorescence or were negative. Positives were characterized by moderate to brilliant fluorescence of typical cell forms, and most nonspecific fluorescence was eliminated with a flazo-orange counterstain. The results indicated that the FAT utilizing multivalent conjugates could be used successfully as an additional method for diagnosis of leptospira infections.

Animals↗
PubMed1994

Experimental porcine reproductive and respiratory syndrome virus infection in one-, four-, and 10-week-old pigs.

One-, 4-, and 10-week-old pigs were exposed to porcine reproductive and respiratory syndrome virus (PRRSV) to determine the effect of age on clinical signs, hematologic alterations, the onset and duration of viremia, routes of virus shedding, antibody production, and microscopic lesions produced by PRRSV isolate ATCC VR-2332. The response to PRRSV infection was similar among age groups. Fever, usually prolonged, and a marked dyspnea with cutaneous erythema when restrained for sample collection were the most consistent clinical signs. Prolonged periocular edema was unique to the 1-week-old pigs. The white blood cell count was decreased on day 4 postexposure (PE) due to decreases in neutrophils and lymphocytes. The virus was isolated from buffy coats at day 1 PE and was isolated from serum, buffy coat, or plasma at each sample collection period through the end of the trial (day 28 PE). Virus was most consistently isolated from lung, lymph node, spleen, and tonsil on day 7 PE and exclusively from lymph node, spleen, and tonsil on day 28 PE. Virus was infrequently isolated from urine and fecal and nasal swabs. Consistent microscopic changes in all age groups included interstitial pneumonia and lymph node hypertrophy and hyperplasia on days 7 and 28 PE, lymph node necrosis on day 7 PE, and subacute mononuclear myocarditis on day 28 PE. Findings presented here indicate that interstitial pneumonia, lymphoid necrosis, and mononuclear myocarditis are characteristic lesions of PRRSV isolate ATCC VR-2332 infection in 1-, 4-, and 10-week-old pigs.

Aging↗
PubMed1994

Mice and rats (laboratory and feral) are not a reservoir for PRRS virus.

Porcine reproductive and respiratory syndrome (PRRS) is caused by an unclassified arterivirus. The syndrome was first reported in the USA in 1987 as epizootics of reproductive failure in sows and respiratory disease in nursery, growing, and fattening pigs. An enzootic form of the disease has now emerged, characterized by interstitial pneumonia and an increased incidence of secondary infections. Because the disease has now become enzootic on many farms, rodents were investigated as a possible reservoir for the infection. Wild rodents from an endemically infected farm were trapped, and virus isolation for PRRS virus (PRRSV) was attempted using porcine primary alveolar macrophage cultures. PRRSV was not isolated from serum and selected pooled tissues (thymus, lung, and spleen) of 14 feral mice and 2 feral rats. Also, transmission experiments were carried out on 3-week-old Balb/c mice and 12-week-old Fischer-344 rats to determine if these species were susceptible to infection. The rodents were inoculated intranasally, orally, and intraperitoneally with a virus proven to transmit PRRS to pigs. Virus isolations from selected pooled tissues (lung, spleen, thymus, and kidney) and from serum were negative, and there were neither gross nor microscopic lesions. Weight gains and white blood cell counts were not significantly different between treated and control groups. These results indicate that rodents are not susceptible to infection with PRRSV and therefore are probably not a reservoir for the disease.

Animals↗
PubMed1999

Reproduction of lesions of postweaning multisystemic wasting syndrome in gnotobiotic piglets.

Neonatal gnotobiotic piglets were inoculated with tissue homogenates and low- and high-passage cell culture material to determine if the lesions of the newly described porcine postweaning multisystemic wasting syndrome (PMWS) could be reproduced. For this, 17 3-day-old gnotobiotic piglets were inoculated intranasally with pelleted chloroform-treated, filtered extracts from cell cultures, filter-sterilized homogenates of lymphoid tissue from PMWS-affected piglets, or control materials. Piglets were maintained in germ-free isolators for up to 5 weeks after infection prior to euthanasia and collection of samples for analysis. All piglets inoculated with the viral inocula developed lesions typical of PMWS, including generalized lymphadenopathy, hepatitis, nephritis, interstitial pneumonia, myocarditis, and gastritis. Porcine circovirus (PCV), as well as porcine parvovirus (PPV), was detected in tissues by virus reisolation, polymerase chain reaction analysis, or immunohistochemistry. All infected piglets developed moderate to high titers of antibody to PCV and moderate titers to PPV. No lesions, virus, or virus-specific antibodies were detected in sham-inoculated or uninoculated control piglets. These studies demonstrate that the lesions of PMWS can be experimentally reproduced in gnotobiotic piglets using filterable viral agents derived from pigs with PMWS and provide an experimental basis for further investigation into the pathogenesis and control of this emerging infectious disease in swine.

Animals↗
PubMed2003

Domestic animals as reservoirs for sleeping sickness in three endemic foci in south-eastern Uganda.

The persistence of sleeping sickness (human African trypanosomiasis) in some areas of south-eastern Uganda has necessitated further investigations, focusing mainly on domestic animals as reservoirs of this disease in three agro-ecological zones. The inter-zone differences in the prevalences of trypanosome infection among cattle (P < 0.001) and pigs (P < 0.001) were significant. Overall, 5.0% of the cattle, 13.9% of the pigs and 0.4% of the small ruminants investigated were found to be infected with parasites of the Trypanosoma brucei subgroup. The results of blood incubation infectivity tests (BIIT) indicated that all of the T. brucei-subgroup isolates from cattle in Kamuli district (zone I) were human-serum-sensitive. Of the zone-I pigs found infected, however, almost all (82.5%) were considered to be infected with T. brucei and many (30.2%) carried human-serum-resistant T. brucei. Pig-tsetse-human appears to be a major transmission cycle in zone I. In Mukono district (zone II), 10.5% and 26.1% of the T. brucei isolates from cattle and pigs, respectively, were human-serum-resistant, indicating that cattle-tsetse-human and pig-tsetse-human are major transmission cycles in zone II. In Tororo district (zone III), 47.3% of the T. brucei isolates from cattle were human-serum-resistant but there were no T. brucei isolates from pigs, indicating that cattle-tsetse-human is the major transmission cycle. Interestingly, as the only T. brucei isolate from sheep in zone III was human-serum-resistant, there may also be a sheep-tsetse-human cycle. In south-eastern Uganda, control efforts must be designed to eliminate the parasites not only from cattle but also from pigs and small ruminants.

Animals↗
PubMed2003

Uptake of colostral immunoglobulins by the compromised newborn farm animal.

Neonatal mortality is very high in farm animals (approximately 10%) and disease resistance is greatly influenced by an adequate passive immunisation just after birth. In piglets, foals, calves and lambs, the intestinal absorption of immunoglobulins from their mother's colostrum occurs mainly by a non-specific endocytosis of macromolecules, but the details of the absorption process, and the mechanisms regulating its cessation after 1-2 days of colostrum exposure, remain poorly understood. In both normal and 'compromised' (premature, growth-retarded, hypoxic, lethargic) newborn farm animals, the intestinal capacity to absorb macromolecules is influenced by both diet- and animal-related factors. Thus, macromolecule uptake is severely reduced in response to premature birth and when macromolecules are to be absorbed from diets other than species-specific colostrum. On the other hand, fetal growth retardation, in vitro embryo production, or a stressful birth process are unlikely to reduce the ability of the intestine to absorb immunoglobulins from colostrum. More knowledge about the diet- and animal-related factors affecting intestinal immunoglobulin uptake will improve the clinical care of 'compromised' newborn farm animals. The present text gives a brief introduction to the process of intestinal immunoglobulin absorption in large farm animals and describe some recent results from the author's own studies in pigs, calves and lambs.

Animals↗
PubMed1997

Microbiological monitoring of laboratory pigs.

Purpose-bred minipigs, are often used as the non-rodent species in toxicology. Infections may interfere with animal experiments, and there are no scientific reasons why the non-rodent species should be of a lower microbiological quality than the rodent species. Therefore, a system for health monitoring of pigs was developed in order to raise the quality of laboratory pigs to the level of laboratory rodents. This system, which includes screening for several viruses, bacteria and ecto- and endoparasites, was used for monitoring minipigs from a barrier unit with the same standards applied to rodents units. In these pigs only rotaviruses are found, which was shown by both serological antibody detection and by detection of rotaviral antigen in faeces. In minipigs from another unit with far less hygienic protection rotaviruses were also found along with certain influenza- and coronaviruses, as well as Pasteurella spp. It is concluded, that it is possible to raise pigs of a microbiological quality comparable to the quality of rats and mice, and that advanced microbiological monitoring in pigs will reveal useful information.

Animals↗
PubMed1991

Prevalence of Listeria monocytogenes in intestinal contents of healthy animals in Japan.

A total of 1,705 fecal specimens or ileo-cecal contents of cattle, pigs, dogs, cats, chicken and rats were submitted for the isolation of Listeria monocytogenes by the use of the combination of Oxford-LPM agar plates after the cold enrichment in PBS at 4 degrees C for 4-6 weeks. Prevalence of L. monocytogenes was found to be 1.9% in cattle, 0.6% in pigs, 0.9% in dogs and 6.5% in rats. However, none of L. monocytogenes was isolated from chicken or cats. Among 26 isolates of L. monocytogenes, 13 strains (50%) were classified into types 1/2a (3 strains), 1/2b (5 strains) and 4b (5 strains) and were often associated with human listeriosis. The majority of the Listeria spp. other than L. monocytogenes isolated from these animals was found to be L. innocua.

Animals↗
PubMed1994

Splenic hamartoblastoma in a sow.

Multiple lesions of splenic hamartoblastoma were found incidentally in a 2- to 3-year-old crossbred sow. The predominant cells, characterized by extreme nuclear irregularity and hemidesmosome-like structures, were considered to be derived from reticular cells of the spleen, and demonstrated infiltrative growth. Their cytological atypism and growth pattern suggest that the present lesions are true neoplasms.

Animals↗
PubMed1995

Experimental infection of SPF piglets with porcine reproductive and respiratory syndrome (PRRS) viruses isolated from two farms.

Porcine reproductive and respiratory syndrome (PRRS) viruses were isolated from pig samples obtained from two farms characterized by an increased number of stillbirth and high mortality in new-born piglets (farm A), and respiratory distress with high mortality in weaning and growing pigs (farm B) in 1993, respectively. When primary specific pathogen-free piglets, 5-day-old or 13-day-old, were experimentally inoculated with the isolates, they showed clinical signs of depress, anorexia, pyrexia, diarrhea, sitting posture and periocular edema. Rate of the weight gain was reduced in the inoculated piglets compared with the non-inoculated pig. There were no apparent differences in clinical signs between the piglets inoculated with the virus samples derived from farms A and B. Microscopically, the most prominent changes observed in experimentally inoculated piglets were interstitial pneumonia, nonpurulent myocarditis and catarrhal lymphnoditis post inoculation day (PID) 28. Viruses were recovered from tissues collected from the inoculated piglets on PID 7 or 28. Furthermore, the viruses were continuously recovered from the sera from PID 7 to PID 28. Antibodies measured by indirect immunofluorescence assay to PRRS virus were first detected in sera on PID 14, and the antibody titer rose to 1:1280 on PID 28.

Animals↗
PubMed1996

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 TGEV and porcine respiratory coronavirus (PRCV), indicating that the isolates were PRCV. In a serological survey of 30 serum samples each collected from about 50 days old pigs in the 2 affected farms, 29 (97%) and 15 (50%) sera were positive for neutralizing antibody against the isolate with the titers ranging from 2 to 64, respectively.

Animals↗
PubMed1996

Ultrastructure of the cyst wall of Sarcocystis species with canine final host in Japan.

The ultrastructural characteristics of cyst wall are a useful clue to the identification of Sarcocystis species. Among the eight species examined, S. cruzi, S. sp. 1 from sheep and S. hircicanis had the thin cyst wall with long, tapered hair-like villar protrusions. The protrusions arose from the dome-like bulges of cyst wall and ran parallel to the surface. No clear ramification was observed in the tip of protrusion of these three species. S. tenella, S. capracanis, S. miescheriana, S. fayeri, and S. sp. 2 from Japanese deer had the thick cyst wall. The villar protrusions of the former three species were palisade-like in shape, but those of S. tenella and S. Capracanis were slightly thinner than those of S. miescheriana. The villar protrusions of S. fayeri and S. sp. 2 were finger-like, but those of the former species were shorter and thicker than those of the latter species. S. fayeri had many minute depressions on the surface of protrusion in a reticular pattern. Microtubules in the core of protrusion were seen in S. miescheriana, S. fayeri and S. sp. 2 but not in the other species. Microdepressions were observed on the surface of cyst wall among the protrusions in all the Sarcocystis species examined, but their function was not made clear.

Animals↗
PubMed2003

Development of a method of diagnosing ovarian disorders in sows and gilts using uterine ultrasonography.

In ultrasonographic diagnosis of ovarian disorders and the estrous cycle in sows, transverse observation of the uterus yielded more characteristic findings than observation of sagittal sections. Transverse ultrasonography revealed that the low progesterone (P) type uterus showed a round structure, while the high P type uterus showed a flattened structure. These results corresponded well with rectal palpation findings: the low P type uterus had a hard, pipe-like structure and the high P type a soft, balloon-like structure. For gilts, we employed a minimum convex type transrectal prostate probe that had an approximately 18 cm insertion handle. The images of the uterus obtained thereby were a similar to those obtained from sows. The above results suggest that it should be possible to diagnose and treat many ovarian disorders in sows and gilts based only on the ultrasonograhic findings. In short, ultrasonograhic findings of a round structure of the uterine wall might be an indication for PMSG (pregnant mare serum gonadotropin) treatment, while findings of a flattened structure might be an indication for PGF(2) (alpha) administration.

Animals↗