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Biomedical subjects

K W Theil

Publications and source records attributed to K W Theil.

At least 19 recordsLinked to original sources
PubMed1995

Rotavirus shedding in feces of gnotobiotic calves orally inoculated with a commercial rotavirus-coronavirus vaccine.

The purpose of this study was to monitor by negative stain electron microscopy the shedding of rotavirus in the feces of gnotobiotic calves orally inoculated with a commercial modified live bovine rotavirus-bovine coronavirus vaccine. Negative stain electron microscopic examination detected vaccine rotavirus in only 1 of 41 daily fecal specimens collected from 3 gnotobiotic calves during the 2 weeks following oral inoculation with a US Department of Agriculture-licensed modified live bovine rotavirus-bovine coronavirus vaccine. In contrast, rotavirus was demonstrable by the same negative stain electron microscopic examination procedure in 17 of 19 fecal specimens collected from diarrheic gnotobiotic or colostrum-deprived calves during the first 8 days after inoculation with virulent bovine rotavirus field strains. Rotavirus was also detected by this procedure in 4 enzyme-linked immunosorbent assay positive fecal specimens collected from naturally-infected diarrheic dairy calves. These results suggest that fecal shedding of vaccine rotavirus demonstrable by electron microscopic examination is uncommon following oral inoculation of calves with the bovine rotavirus-bovine coronavirus vaccine.

Animals↗
PubMed1993

Serologic evidence for rabbit syncytium virus in eastern cottontail rabbits (Sylvilagus floridanus) in Ohio.

Thirteen of 20 eastern cottontail rabbit (Sylvilagus floridanus) sera collected near Delaware, Ohio (USA) in 1991 were positive by indirect immunofluorescent antibody test (IFAT) for antibody to rabbit syncytium virus (RSV), a Kemerovo serogroup orbivirus. In addition, two of 10 domestic bovine sera and three of 30 sheep sera collected in southeastern Ohio gave weak positive IFAT reactions to RSV.

Animals↗
PubMed1991

Rabbit syncytium virus is a Kemerovo serogroup orbivirus.

Polyacrylamide gel genome electropherotyping and negative-stain electron microscopic studies, along with immunofluorescent staining and immune electron microscopy reactions, indicate that rabbit syncytium virus has the morphologic, genomic, and antigenic attributes of a Kemerovo serogroup orbivirus.

Animals↗
PubMed1989

Molecular epidemiology and subgroup determination of bovine group A rotaviruses associated with diarrhea in dairy and beef calves.

The genome electropherotyping technique was used to examine group A rotaviral infections of diarrheic calves ranging from 1 to 85 days of age in 2 beef and 27 dairy herds. Coelectrophoresis studies demonstrated 38 distinct bovine group A rotavirus genome electropherotypes; all were long genome electropherotypes, and none had extra segments or unusual segment rearrangements. Genome electropherotypes in fecal specimens from diarrheic calves previously inoculated orally with a commercial, modified-live group A rotavirus vaccine differed from the vaccine genome electropherotype. Generally, when fecal specimens for genome electropherotyping were collected from two or more different calves within the same herd over a relatively short time, only one genome electropherotype was detected within a given herd. Different genome electropherotypes were detected in the same herd, however, when fecal specimens were obtained from different diarrheic calves over longer intervals (6 months or more). Twenty-three group A rotavirus strains with distinct genome electropherotypes, from diarrheic calves in 22 herds, were isolated and plaque purified in cell culture, and all were subgroup 1 group A rotaviruses. Non-group A rotavirus genome electropherotypes were not detected in 131 fecal specimens, negative for group A rotavirus, collected from diarrheic calves in 17 dairy herds.

Animals↗
PubMed1988

Partial characterization of a bovine group A rotavirus with a short genome electropherotype.

A group A rotavirus (ID isolate) recovered from a diarrheic beef calf possessed a short genome electropherotype. This short genome electropherotype was a stable characteristic of the ID isolate as it remained unchanged through 3 passages in gnotobiotic calves or through 19 passages in MA104 cell cultures. Subgroup analysis with monoclonal antibodies in an enzyme-linked immunosorbent assay established that the isolate was a subgroup 1 rotavirus. Neutralization tests demonstrated that this isolate was a distinct serotype from the human group A rotavirus S2 isolate (short genome electropherotype) and the turkey group A rotavirus 174 isolate (semi-short genome electropherotype). The ID isolate was pathogenic for 5- to 21-day-old gnotobiotic calves, inducing diarrhea within 48 h postinoculation.

Animals↗
PubMed1987

Physicochemical characterization of porcine pararotavirus and detection of virus and viral antibodies using cell culture immunofluorescence.

A cell culture immunofluorescence (CCIF) assay was optimized for detection of porcine pararotavirus (group C rotavirus) in intestinal contents. The greatest viral infectivity was observed when MA104 cells (5 days after subculturing) were rinsed and refed in serum-free medium before inoculation, pancreatin was added to the inocula, and the inocula were centrifuged onto the cells. Gentamicin treatment of pararotavirus samples to reduce bacterial contamination also reduced the viral infectivity of these samples for MA104 cells. An indirect CCIF assay was used to determine the prevalence of pararotavirus and rotavirus antibodies in pig sera. In pigs from four herds, pararotavirus antibodies were detected in 100% (68 of 68) of adults and 59% (24 of 41) of weanling pigs, while 86% (24 of 28) of nursing pigs from 12 herds had pararotavirus antibodies. The physicochemical properties of pararotavirus were examined and compared with those of group A rotaviruses by using the CCIF assay to quantitate in vitro changes in viral infectivity. Pararotavirus was inactivated (greater than or equal to 99% reduction in titer) by heating to 56 degrees C for 30 min, was slightly labile at pH 3 (16 to 34% reduction in titer), and was stable at pH 5 (0 to 17% reduction in titer) and in either (3 to 19% reduction in titer). One group A rotavirus (Gottfried strain) was stable at 56 degrees C (0% reduction in titer), whereas the OSU strain of group A rotavirus was inactivated at this temperature (99% reduction in titer).

Animals↗
PubMed1987

Age-related infections with rotavirus, rotaviruslike virus, and atypical rotavirus in turkey flocks.

The genome electropherotyping technique was used in longitudinal surveys to detect group A rotavirus, rotaviruslike virus (RVLV), atypical rotavirus (ATR), and reovirus in intestinal contents or fecal specimens collected from turkeys in 10 commercial and 2 research station flocks. These viruses were detected in turkeys from 8 to 10 commercial flocks surveyed. Of 278 specimens collected from turkeys less then 29 days old in commercial flocks, 79 (28.4%) contained one or more viruses, whereas only 1 of 120 specimens collected from turkeys older than 28 days had virus. Viruses were detected in commercial turkeys between 3 and 35 days old, and over a third of the specimens collected from birds during their first week of life were positive for group A rotavirus. Between 8 and 28 days of age, commercial turkeys were infected with group A rotavirus, RVLV, ATR, and reovirus. ATR was the only virus detected in birds older than 28 days. Overall, group A rotavirus and RVLV were each detected in 39 specimens, and ATR was detected in 7 specimens; reovirus was detected in 2 specimens. Eight of the positive specimens contained two viruses. All 102 specimens collected from turkeys 1 to 56 days old in the two research station flocks were negative for virus.

Aging↗
PubMed1986

Comparison of immune electron microscopy and genome electropherotyping techniques for detection of turkey rotaviruses and rotaviruslike viruses in intestinal contents.

Seventy-nine intestinal contents specimens from 65 turkey flocks were examined for rotavirus and rotaviruslike virus (RVLV) by immune electron microscopy (IEM) and genome electropherotyping. The IEM procedure was slightly more sensitive in detecting these viruses; 7 of 48 specimens (14.6%) positive for virus by IEM were negative by the genome electropherotyping technique. The genome electropherotyping technique more readily differentiated the rotaviruses and RVLVs than did the IEM procedure; 15 of 48 specimens (31%) positive for virus by IEM could not be differentiated into rotavirus of RVLV, whereas only 4 of the 41 specimens (9.7%) positive by genome electropherotyping produced incomplete genome electropherotypes and could not be differentiated. Thirty-one specimens negative by IEM were also negative by genome electropherotyping. Specimens determined to contain only rotavirus by IEM produced only rotavirus genome electropherotypes. Likewise, specimens determined to contain RVLV alone by IEM produced only RVLV genome electropherotypes. Three specimens contained viruses morphologically resembling rotaviruses that were not aggregated by either the anti-turkey rotavirus serum or the anti-turkey RVLV serum and possessed genome electropherotypes distinct from those of the turkey rotavirus and RVLV. These rotaviruses may represent a third, previously unrecognized serogroup of turkey rotaviruses.

Animals↗
PubMed1986

Experimentally induced coronavirus infections in calves: viral replication in the respiratory and intestinal tracts.

Eleven 3- to 50-day-old colostrum-deprived gnotobiotic calves and seven 25- to 63-day-old colostrum-deprived conventional calves were allotted into 3 groups. Each group was inoculated with a fecal isolate of bovine coronavirus via different routes: orally/intranasally OR/IN, No. 1 through 8, group 1 calves; OR, No. 9 through 13, group 2 calves; IN, No. 14 through 18, group 3 calves. Nasal swab specimens and fecal specimens were collected daily and were examined for coronavirus antigen by use of direct immunofluorescent staining (nasal epithelial cells) or by use of immune electron microscopy (fecal specimens). All but 4 calves (No. 11, 13, 17, and 18) were euthanatized on postinoculation days (PID) 3 to 7. Calves 11 and 17 became severely dehydrated and died at PID 5. Calves 13 and 18 were evaluated for nasal and fecal shedding of coronavirus through PID 14. Distribution of coronavirus antigen in the respiratory and intestinal tracts of the 14 euthanatized calves was evaluated by use of direct immunofluorescent staining. All calves developed profuse diarrhea by PID 2 to 4; however, calves did not develop clinical signs of respiratory tract disease before euthanasia or death. Inoculated calves shed coronavirus in their feces as detected by use of immune electron microscopy. Infected nasal epithelial cells were detected in all but 2 orally inoculated calves (No. 9 and 10). Route of inoculation influenced the sequence of initial detection of coronavirus antigen from fecal specimens or nasal swab specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Efficacy of an orally administered modified-live porcine-origin rotavirus vaccine against postweaning diarrhea in pigs.

A commercially available, porcine-origin rotavirus vaccine was evaluated for efficacy against postweaning diarrhea due to rotavirus infection in pigs. Weight gains were compared at 5 intervals after weaning. Visual scoring was used to evaluate fecal consistency. Rectal swab specimens were cultured for hemolytic E coli and evaluated for rotaviral antigen by use of enzyme-linked immunosorbent assay. Milk from dams and sera from pigs and dams were evaluated for rotavirus-neutralizing antibodies by use of a plaque-reduction test. Significant differences between vaccinates and controls were not found in the determinants evaluated. Selected rotavirus-positive fecal and rectal swab specimens were examined for double-stranded (ds) RNA by use of direct electropherotyping, and the results were compared with the dsRNA pattern of rotavirus propagated from the vaccine. Only electropherotypes typical of field strain virus were found in the fecal and rectal swab specimens evaluated. Sera from guinea pigs and from a gnotobiotic pig immunized against the field strain rotavirus neutralized Ohio State University strain rotavirus (homologous to the vaccine rotavirus strain), but did not neutralize the Gottfried strain of rotavirus. This indicated that, although the dsRNA electropherotypes of the field and vaccine strains of the virus were different, the serotypes were similar, if not identical.

Administration, Oral↗
PubMed1986

Study of porcine postweaning diarrhea involving K88(-) hemolytic Escherichia coli.

The onset of fecal shedding, serogroup involvement, and association of hemolytic Escherichia coli with the postweaning diarrhea syndrome were studied in swine. The only E coli O antigen, detected by slide agglutination with the antisera used, was O157; K antigens were not detected. The ligated intestinal loop test (LILT) was used for enterotoxigenicity testing. All O157 serogroup isolates (n = 9) were hemolytic, and 89% (8 of 9) were LILT positive. Of all hemolytic isolates tested, 59% (10 of 17) were LILT positive. Twenty-seven nonhemolytic isolates were tested for enterotoxigenicity; of these, 45% (12) were LILT positive. The onset of postweaning diarrhea coincided with the modal onset of hemolytic E coli shedding at postweaning day 7. At postweaning day 7, hemolytic E coli shedding was concurrently associated with diarrhea (P less than 0.0005), whereas later during the postweaning period, this was not the situation.

Animals↗
PubMed1985

Porcine rotavirus-like virus (group B rotavirus): characterization and pathogenicity for gnotobiotic pigs.

A rotavirus-like virus (RVLV) was isolated from a diarrheic pig from an Ohio swine herd. This virus infected villous enterocytes throughout the small intestine of gnotobiotic pigs and induced an acute, transitory diarrhea. Complete virions were rarely observed in the intestinal contents of infected animals; the predominant particle detected by immune electron microscopy was a corelike particle 52 nm in diameter. The genome of the porcine RVLV was composed of 11 discrete segments of double-stranded RNA that produced an electropherotype distinct from the genome electropherotypes of reovirus, rotavirus, and porcine pararotavirus. Porcine RVLV was antigenically unrelated to rotavirus, porcine pararotavirus, or reovirus but was antigenically related to a bovine RVLV.

Animals↗