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Biomedical subjects

L D Olson

Publications and source records attributed to L D Olson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Clinical evaluation of transmissible gastroenteritis virus vaccines and vaccination procedures for inducing lactogenic immunity in sows.

Two federally licensed attenuated live transmissible gastroenteritis (TGE) virus vaccines (an IM vaccine and an oral-IM vaccine) and 1 nonlicensed nonattenuated live TGE virus vaccine were evaluated and compared in sows free of TGE virus-neutralizing antibodies. Litters from the sows were challenge exposed at 3 and 5 days of age, and results were combined according to the vaccine administered to the sows. The survivability of pigs suckling sows vaccinated with the nonattenuated vaccine was significantly (P less than 0.01) greater than that of pigs suckling sows vaccinated with the IM attenuated vaccine, significantly (P less than 0.05) greater than that of pigs suckling sows vaccinated with the oral-IM attenuated vaccine, and significantly (P less than 0.05) greater than that of pigs suckling sows that had not been vaccinated. The differences, however, between survivability of litters from sows vaccinated with the IM attenuated vaccine or the oral-IM attenuated vaccine and that of litters from the sows not vaccinated were not significant (P greater than 0.10). The nonattenuated TGE vaccine, although giving a higher level of protection than the attenuated vaccine, was eventually overwhelmed. Dexamethasone did not increase the incidence of diarrhea, and levamisole did not potentiate the lactogenic immunity in sows after given their first dose of the nonattenuated vaccine. Survivability in litters suckling sows that developed diarrhea after given their first dose of the nonattenuated vaccine was not greater than that in litters suckling sows that did not develop diarrhea. The best results were obtained when 3-day-old suckling pigs were challenge exposed with virulent TGE virus.

Animals↗
PubMed1989

Relationship among transmissible gastroenteritis virus antibody titers in serum, colostrum, and milk from vaccinated sows, and protection in their suckling pigs.

We studied the antibody responses to transmissible gastroenteritis (TGE) in serum, colostrum, and milk from sows vaccinated with 2 attenuated (1 IM and 1 oral-IM) and 1 nonattenuated live vaccines and the relationship of these responses with the survivability of the sow's suckling pigs after challenge exposure with virulent TGE virus. Contrary to previous studies, the anti-TGE virus-neutralizing geometric mean titers (GMT) in the milk of sows vaccinated with attenuated vaccines at 3 and 5 days of lactation were similar to that found in the colostrum. Colostral and serum antibody titers were highest in sows given 2 injections of the IM attenuated vaccine. Half of the sows given the oral-IM attenuated vaccine did not seroconvert after 2 oral doses. Only sows vaccinated with the nonattenuated live vaccine had milk GMT that remained high for 21 days after farrowing. The linear relationship between colostral GMT and percentage of survivability of suckling pigs challenge exposed at 3 days of age was significant (P less than 0.05), although the relationship between serum GMT and percentage of survivability and the relationship between milk GMT and percentage of survivability were not significant (P greater than 0.10). The linear relationship between colostral (P less than 0.10) or pre-challenge exposure milk (P less than 0.05) GMT and percentage of survivability of suckling pigs challenge exposed at 5 days of age was significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Tiamulin in drinking water for treatment and development of immunity to swine dysentery.

The diarrhea of swine dysentery receded in swine treated with 60 or 45 mg of tiamulin/L of drinking water (60 or 45 ppm). However, within 2 to 10 days (average 4.1 days) after drug withdrawal, diarrhea recurred. Tiamulin (22.5 mg/L in drinking water) did not markedly reduce the diarrhea during medication, and tylosin (66 mg/L in the drinking water) was not effective. In swine treated with 120 mg of dimetridazole/L of drinking water, there was no recurrence of diarrhea. After the recurrence of diarrhea in swine, repeated medication with tiamulin in drinking water reduced the severity of diarrhea and prevented deaths. After 1 to 3 retreatments, swine were immune to exposure with swine dysentery inoculum, and there was a significant (P less than 0.05) increase in their serum anti-Treponema hyodysenteriae antibodies. Seemingly, drug withdrawal permitted the occurrence and recurrence of diarrhea that was necessary to stimulate immunity.

Animals↗
PubMed1986

Feeding sodium arsanilate for exciting diarrhea and identifying carriers of swine dysentery.

Sodium arsanilate was fed to nondiarrhetic swine, previously exposed to and treated for swine dysentery, for the purpose of inducing them into developing a swine dysentery diarrhea. From 40 to 100% of these swine in each pen had previously had a swine dysentery diarrhea. The isolate of Treponema hyodysenteriae in the diced colon which was used to expose the swine was resistant to sodium arsanilate. After an interim of no treatment for swine dysentery, sodium arsanilate was fed at a level of 220 parts per million for 21 days. Of the 14 pens containing swine fed sodium arsanilate, ten pens had one or more swine that developed a swine dysentery diarrhea while being fed sodium arsanilate. This was significantly (P less than 0.05) greater than the three pens that each had one pig that developed a swine dysentery diarrhea of 13 pens containing similar swine not fed sodium arsanilate during a comparable period. In the 14 pens containing swine fed sodium arsanilate, 14 swine were the first to develop a swine dysentery diarrhea since in four pens, two swine in each pen developed diarrhea within 24 hours of each other. This also was significantly (P less than 0.01) greater than the three swine in the ten pens not fed sodium arsanilate. From these results, it was theorized that sodium arsanilate excited the nondiarrhetic carrier into developing a swine dysentery diarrhea and that this phenomenon may have potential in identifying the carrier state.

Animals↗
PubMed1986

Probable elimination of swine dysentery after feeding ronidazole, carbadox or lincomycin and verification by feeding sodium arsanilate.

Swine dysentery did not recur during a nine week period after withdrawal of medication in swine fed ronidazole at a level of 60 parts per million of feed for ten weeks or fed either carbadox at 55 ppm or lincomycin at 110 ppm of feed for six weeks. During this period swine dysentery was neither transmitted to accompanying sentinels after the withdrawal of the above medication or was Treponema hyodysenteriae isolated and cultured or observed in stained smears from rectal swabs and feces or from colonic scrapings at necropsy. Beginning three weeks after the withdrawal of medication, all swine were fed sodium arsanilate at a concentration of 220 ppm of feed for three weeks in an attempt to excite the carrier of swine dysentery into developing a swine dysentery diarrhea. A swine dysentery diarrhea did recur during the feeding of sodium arsanilate in swine previously fed ronidazole at a level of 60 ppm of feed for only six weeks. It was concluded: that swine dysentery was probably eliminated with the feeding of ronidazole for the longer duration and with the feeding of carbadox and lincomycin and that sodium arsanilate was of value in identifying the carrier state.

Animals↗
PubMed1983

Comparison of stained smears and culturing for identification of Treponema hyodysenteriae.

A comparative study was made of stained fecal smears and cultured fecal swabs for identification of the large spirochetes Treponema hyodysenteriae and Treponema innocens. Feces were obtained by swabbing rectums, colons, and stools of nonexposed swine and swine experimentally exposed to swine dysentery. In this study there was a significant (P less than 0.001) correlation between the observation of one or more large spirochetes on stained slides and obtaining either a strong or a weak beta-hemolytic reaction in culture. A significant (P less than 0.001) correlation was also found between the observation of one or more large spirochetes on stained smears or obtaining either a strong or a weak beta-hemolytic reaction in culture and the occurrence of either nonhemorrhagic or hemorrhagic diarrhea in the swine. In the diarrheic swine at the time of swabbing, 157 of 393 samples (40%) were negative for both the presence of large spirochetes on stained smears and the production of either a strong or a weak beta-hemolytic reaction; in nondiarrheic swine, 42 of 278 samples (15.1%) were positive in stained smears and 32 of 268 samples (11.9%) were positive by culturing. In swine infected with swine dysentery, 17 of 1,011 samples produced weak beta-hemolytic reactions, and in swine infected with nonpathogenic large spirochetes of T. innocens, three of 34 samples produced strong beta-hemolytic reactions. It was concluded from this study that neither staining rectal smears nor culturing rectal swabs is sufficient, either together or alone, for the diagnosis of swine dysentery; however, these laboratory methods could be highly supportive of a diagnosis of swine dysentery in swine with clinical signs and lesions of the disease.

Animals↗
PubMed1983

Mutagen sensitivity of Neurospora meiotic mutants.

The Neurospora meiotic mutants, mei-1, mei-2, mei-3, and mei-4 were tested for cross sensitivity to mutagens. Mei-2 and mei-3 are sensitive to MMS, gamma-irradiation and histidine. Mei-2 is not sensitive to ultraviolet (UV) at 20 degrees C. Tests with recombinants with crossovers to either side of mei-2 or mei-3 show that these traits are the pleiotropic properties of a single gene which also determines meiotic behavior. The mei-2 gene maps to the right of al-3 on linkage group V. It is not allelic to mus-11. Upon backcrossing, the originally dominant meiotic effect of mei-2 becomes recessive to partially dominant. The histidine sensitivity is recessive.

Alleles↗
PubMed1983

Detecting anti-Treponema hyodysenteriae antibodies in swine serum using immunofluorometry.

An indirect fluorescent antibody test was adapted for measuring serum anti-Treponema hyodysenteriae antibodies with a fluorometer. The immunofluorescence was recorded as fluorescent signal units. Cultures of T. hyodysenteriae and Treponema innocens were used as antigen. There was a significant (P less than 0.01) correlation between the immunofluorescence recorded with the fluorometer and that evaluated visually with a microscope. The swine exposed orally to swine dysentery infective inoculum and subsequently hyperimmunized by the intravenous inoculation of live cultures of T. hyodysenteriae had the highest average fluorescent signal unit, which was 104.5. There was a significant (P less than 0.01) correlation between the level of anti-T. hyodysenteriae antibody and the interval length between the last day of diarrhea and the day of bleeding. However, in measuring fluorescent signal units in serum from swine infected with nonpathogenic large spirochetes, (T. innocens), there was also a significant (P less than 0.01) correlation between T. hyodysenteriae and T. innocens as antigen. The coefficient of variation of the average fluorescent signal unit for a highly positive serum and a highly negative serum between 16 runs of assays were 5.7% and 19% respectively; the coefficient of variation of the average fluorescent signal unit for duplicate samples on 358 serum samples tested was 5.8%.

Animals↗
PubMed1983

Frequency of jowl abscesses in feeder and market swine exposed to group E streptococci as nursing pigs.

Weaning and isolation were evaluated as management methods in controlling streptococcic lymphadenitis of swine. Nursing pigs in 3 experiments were exposed to group E streptococcus (GES) by contact with their GES-inoculated dams or other GES-inoculated pen mates. The exposed pigs were either weaned and isolated when 5, 6, or 8 weeks old or left in contact with the inoculated swine until 14 to 32 weeks old when all were necropsied. Abscesses were not recognized in 13 weaned or 7 unweaned pigs necropsied at 14 to 15 weeks of age, but GES was isolated from mandibular lymph nodes of 4 of the 7 unweaned pigs. Abscesses were recognized in 1 of 49 unweaned and 4 of 53 weaned swine when examined at market weight (24 or 32 weeks of age). In the 3rd experiment, 10 of 11 inoculated sows, one of 33 unweaned, and 11 of 25 weaned swine had serum titers greater than 4 to GES in a microtitration agglutination test.

Abscess↗
PubMed1981

Influence of prior hauling on pathogenesis of Pasteurella multocida in turkeys.

Turkeys were hauled in a truck and exposed to Pasteurella multocida in the drinking water. The clinical course of fowl cholera was modified in hauled turkeys as compared to unhauled turkeys by delaying the onset of depression and reducing the severity of the disease. In unhauled turkeys, there was a marked increase in mortality in the first experiment and a marked increase in depression at the end of the second experiment. In both experiments average cloacal temperature was higher during the first 5 days after inoculation in unhauled than in hauled turkeys. On the day after hauling, plasma corticosterone concentration decreased in both hauled and unhauled turkeys.

Animals↗
PubMed1981

Gross and microscopic lesions of middle and inner ear infections in swine.

In all infected middle ears from 36 swine, there was purulent material in the tympanic cavity and tympanic bulla. Frequently, there were lysis of the tympanic membrane and ossicles and purulent material in the external ear canal. Sometimes, there were desquamation of the stratified squamous epithelium lining the tympanic cavity, and osteolysis of the underlying osseous wall with subsequent fibrosis. In those swine with inner ear infections, there were infiltration of neutrophils and fibrin in the cochlea and vestibule. The predominant isolation from the infected middle ears was non-groupable beta-hemolytic streptococci, although isolations of streptococcic groups C, E, and G, Pasteurella multocida, and Corynebacterium pyogenes were made.

Animals↗
PubMed1981

Induction of swine dysentery in swine by the intravenous injection of filtered Treponema hyodysenteriae.

Swine dysentery was induced in 18 swine exposed by intravenous injection of a filtrate which contained Treponema hyodysenteriae and was obtained from macerated colonic scrapings of swine dysentery. However, swine dysentery did not develop in swine injected intravenously with a pure culture of T. hyodysenteriae or when combined with a colonic filtrate from normal swine. Diarrheal feces from the swine injected intravenously with the filtered T. hyodysenteriae contained more mucus, and fecal smears contained more T. hyodysenteriae and fewer other bacteria than did swine exposed orally to colon infected with swine dysentery or filtered T. hyodysenteriae. In the colons of the 12 swine injected intravenously with filtered T. hyodysenteriae that died, there was a minimum amount of croupous membrane and, microscopically, the T. hyodysenteriae were located deep in the colonic crypts. Five of the six surviving swine injected intravenously with filtered T. hyodysenteriae developed serum anti-T. hyodysenteriae antibodies using the indirect fluorescent antibody test and four of these swine developed diarrhea when reexposed with swine dysentery infected colon six weeks after initial exposure. None of the swine injected intravenously with cultured T. hyodysenteriae developed serum anti-T. hyodysenteriae antibodies and all were highly susceptible to swine dysentery.

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↗
PubMed1980

Mutagen-sensitive mutants in Neurospora.

Initial work on the fungus Neurospora crassa has shown that a least two DNA-repair systems exist in this eukaryote: excision repair and a mutation-prone repair. The evidence suggests that there is also a third repair system. Recently, new mutagen-sensitive strains have been isolated in several laboratories, but they are not yet fully characterized. A hunt for cytoplasmically inherited UV sensitivity has failed to turn up any such mutants among 25 new UV-sensitive isolates.

DNA Repair↗
PubMed1980

Upper lethal environmental temperature in turkeys.

Of a total of 16 turkeys in a temperature controlled chamber with a low air velocity, 14 died during an accidental 16-hr exposure, because of a malfunction of a thermostat, to a temperature of 38.5 C and 80% relative humidity. These turkeys had been previously maintained at a temperature of 20 C for 6 days. Of the 2 surviving turkeys, one alert and one depressed, there were 1) an increased percent erythrocytes in the hematocrit, 2) a decreased ratio of blood mononuclear cells to blood polymorphonuclear cells, 3) a marked increase in plasma corticosterone concentration, and 4) a definite reduction of lymphocytes in the bursal follicles of the alert turkey and a nearly complete depletion in the depressed turkey.

Adrenal Glands↗
PubMed1980

Experimental induction of cutaneous streptococcal abscesses in swine as a sequela to swinepox.

Streptococcal abscesses were experimentally induced in skin of swine as a sequela to swinepox. Swinepox lesions were more uniform in distribution when infection was induced by IV injection of swinepox virus than when induced by lice (Haematopinus suis) or scarification of skin. The incubation period for swinepox was between 10 and 14 days when virus was administered IV. Cutaneous abscesses developed in swine given IV injection of streptococci 10 and 14 days after they were injected with swinepox virus, but not when they were given the streptococci 7 days after virus injection or simultaneously with virus injection. Abscesses did not develop when streptococci were applied topically to swinepox lesions.

Abscess↗