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R W Fulton

Publications and source records attributed to R W Fulton.

At least 19 recordsLinked to original sources
PubMed2005

Diagnosis of infectious canine hepatitis virus (CAV-1) infection in puppies with encephalopathy.

Nine weaned Labrador Retriever puppies from a litter of 11 were presented with signs of acute central nervous system (CNS) disease that included ataxia and blindness. All puppies died. Gross examination of tissues from 2 puppies revealed regionally diffuse hemorrhages in the brain stem and swollen hemorrhagic lymph nodes. Light microscopic examination of hematoxylin and eosin-stained tissues showed numerous large, basophilic intranuclear inclusion bodies within CNS vascular endothelium and occasionally in individual hepatocytes. Immunohistochemical staining of the tissue was positive using an antibody against canine adenovirus-1. Virus isolation for infectious canine hepatitis virus was achieved using inoculated cell cultures. Polymerase chain reaction amplification of DNA from cell culture material revealed shared homology with other mammalian adenoviruses.

Animals↗
PubMed2005

Viral antigen distribution in the respiratory tract of cattle persistently infected with bovine viral diarrhea virus subtype 2a.

Tissues were obtained at necropsy from the nasal vestibule, turbinates, nasopharynx, trachea, tracheobronchial bifurcation, and lung from each of 10 clinically healthy calves persistently infected (PI) with bovine viral diarrhea virus (BVDV) serotype 2a. Tissues from the nasal vestibule were obtained by biopsy from five additional PI calves. Formalin-fixed tissues were processed for immunohistochemistry to localize the distribution of BVDV throughout the respiratory tract. Antigen distribution and intensity were subjectively evaluated. Throughout the respiratory tract, mononuclear leukocytes, vascular smooth muscle, and endoneural and perineural cells had BVDV immunoreactivity (BVDV-IR). Multifocally, squamous and ciliated columnar epithelium throughout the respiratory tract contained weak to moderate BVDV antigen. Viral antigen was not seen in goblet cells. BVDV-IR in mixed tubuloalveolar glands of the nasal cavity was weak to strong in serous secretory cells and ductular epithelium. Chondrocytes of the concha often contained BVDV antigen diffusely. Nasal mucus-secreting and tracheobronchial glands multifocally contained weak viral signal. In all cases, alveolar macrophages had moderate to strong BVDV-IR, whereas BVDV-IR in alveolar epithelial cells was weak to moderate. BVDV was present in interalveolar leukocytes and mesenchymal cells. Results indicate that serous secretions of the nasal cavity, productive viral infection of epithelium, and infected leukocytes in respiratory secretions are likely major sources of infectious BVDV from PI calves. The presence of BVDV antigen in respiratory epithelium is, at least, indirect support for the notion that this virus predisposes PI cattle to secondary microbial infections.

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PubMed2003

Humoral immune response and assessment of vaccine virus shedding in calves receiving modified live virus vaccines containing bovine herpesvirus-1 and bovine viral diarrhoea virus 1a.

Susceptible calves were administered modified live virus (MLV) vaccines containing bovine herpesvirus-1 (BHV1) and bovine viral diarrhoea type 1 (BVDV1a) strains intramuscularly, with one vaccine containing both MLV and inactivated BHV-1 and inactivated BVDV1a. There was no evidence of transmission of vaccine (BHV-1 and BVDV1a) strains to susceptible non-vaccinated controls commingled with vaccinates. No vaccinates had detectable BHV-1 in peripheral blood leucocytes (PBL) after vaccination. Each of three vaccines containing an MLV BVDV1a strain caused a transient BVDV vaccine induced viremia in PBL after vaccination, which was cleared as the calves developed serum BVDV1 antibodies. The vaccine containing both MLV and inactivated BHV-1 induced serum BHV-1 antibodies more rapid than MLV BHV-1 vaccine. Two doses of MLV BHV-1 (days 0 and 28) in some cases induced serum BHV-1 antibodies to higher levels and greater duration than one dose.

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PubMed2001

Development of an ex vivo model to study adherence of Mannheimia haemolytica serovar 1 to mucosal tissues of the respiratory tract of cattle.

OBJECTIVE: To develop and validate an ex vivo model for study of adherence of Mannheimia haemolytica (formerly Pasteurella haemolytica) to respiratory tract mucosa of cattle and to use this model to confirm adherence of M haemolytica serovar 1 (Mh1) to several relevant respiratory mucosal surfaces. SAMPLE POPULATION: Excised nasal, nasopharyngeal, turbinate, and tonsillar mucosal tissue from the bovine upper respiratory tract. PROCEDURE: Mh1 was radiolabeled by use of tritiated leucine. Various concentrations of labeled bacteria were incubated with bovine upper respiratory tract tissues for various times. Tissue was washed to remove nonadherent bacteria, and percentage of bacteria adhered (percentage of adherence) was estimated using radioactivity. Using an optimal inoculum concentration and incubation time, percentage of Mh1 adherence was compared on nasal, nasopharyngeal, turbinate, and tonsillar mucosal tissue, and adherence to nasopharyngeal tissue was confirmed by scanning and transmission electron microscopy. RESULTS: The optimal Mh1 inoculum concentration was 1 X 10(7) colony forming units/ml and incubation time was 3 hours. Percentage of adherence of Mh1 to nasopharyngeal tissue was greater than adherence to other tissue types. CONCLUSIONS AND CLINICAL RELEVANCE: The ex vivo model maintained the functional and structural integrity of bovine upper respiratory tract mucosa, as confirmed by light and electron microscopy. Electron microscopy revealed participation of epithelial cell cilia and surface mucus in adherence of Mh1 to nasopharyngeal tissue. Adherence of Mh1 was confirmed in repeated assays, indicating that this organism adheres to upper respiratory tract mucosa of cattle.

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PubMed2000

Bovine viral diarrhea virus types 1 and 2 antibody response in calves receiving modified live virus or inactivated vaccines.

Serums from calves receiving eight different commercial vaccines containing modified live virus (MLV) or inactivated bovine viral diarrhea virus (BVDV) immunogens were assayed for antibodies to types 1 and 2 BVDV strains. The immune response to the types 1 and 2 BVDV strains were evaluated in 48 calves receiving one of the eight vaccines for each group. For 7/8 vaccines, the BVDV vaccine immunogen was only type 1 whereas the remaining vaccine contained both types 1 and 2 immunogens. Calves administered MLV vaccine received only one dose at day 0, whereas those calves receiving the inactivated vaccines were administered two doses initially at days 0 and 28. Selected calves were revaccinated with only one dose at day 140. Animals vaccinated with type 1 vaccines developed titers to a broad range of type 1 BVDV, both cytopathic (CP) and noncytopathic (NCP) biotypes, with lower titers evident to type 2 BVDV strains. For some animals, the BVDV serum antibodies did not persist. Revaccination at day 140 induced a significant four-fold increase in animals with intermediate to low antibody titers. There did not appear to be any clear differences in antibody responses between type 1 MLV or inactivated vaccines. The calves receiving the inactivated vaccine containing types 1 and 2 had similar antibody levels to both types.

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PubMed2000

Bovine viral diarrhea virus cytopathic and noncytopathic biotypes and type 1 and 2 genotypes in diagnostic laboratory accessions: clinical and necropsy samples from cattle.

One hundred three bovine samples submitted to the Oklahoma Animal Disease Diagnostic Laboratory (OADDL) that were positive for bovine viral diarrhea virus (BVDV) were typed by a nested reverse transcription-polymerase chain reaction for BVDV genotypes. These BVDV samples included supernatants from virus isolation (79), serums (17), and buffy coats (7). The biotype, cytopathic (CP) or noncytopathic (NCP), was determined by cell culture virus isolation. Twenty-eight of 103 samples were submitted for herd screening for BVDV, 32 from OADDL necropsy cases, and 43 from live cattle with varied clinical conditions. Two samples contained 2 bands indicating presence of both BVDV types 1 and 2. Of the 105 BVDV samples, 26 were type 1 CP strains (24.8%), 38 were type 1 NCP strains (36.2%), 10 were type 2 CP strains (9.5%), and 31 were type 2 NCP strains (29.5%). From the 105 BVDV isolates, NCP biotypes were isolated more frequently (69, 65.7%) than CP biotypes (36, 34.3%), and type 1 genotypes were more frequently isolated (64, 61.00%) than type 2 genotypes (41, 39.0%). The NCP strains were more common than CP in herd screening samples. Cattle with respiratory disease history at time of sampling had more NCP than CP biotypes and more type 1 than type 2 genotypes. Of the necropsy cases, more were type 1 than type 2 genotypes for the respiratory cases with fibrinous pneumonia, more were type 1 than type 2 genotypes in cattle with enteritis/colitis without systemic lesions, and more were CP than NCP biotypes in cattle with enteritis/colitis with systemic lesions. No CP biotype was isolated from serum samples.

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PubMed2000

Bovine viral diarrhea viral infections in feeder calves with respiratory disease: interactions with Pasteurella spp., parainfluenza-3 virus, and bovine respiratory syncytial virus.

The prevalence of bovine viral diarrhea virus (BVDV) infections was determined in a group of stocker calves suffering from acute respiratory disease. The calves were assembled after purchase from Tennessee auctions and transported to western Texas. Of the 120 calves, 105 (87.5%) were treated for respiratory disease. Sixteen calves died during the study (13.3%). The calves received a modified live virus BHV-1 vaccine on day 0 of the study. During the study, approximately 5 wk in duration, sera from the cattle, collected at weekly intervals, were tested for BVDV by cell culture. Sera were also tested for neutralizing antibodies to BVDV types 1 and 2, bovine herpesvirus-1 (BHV-1), parainfluenza-3 virus (PI-3V), and bovine respiratory syncytial virus (BRSV). The lungs from the 16 calves that died during the study were collected and examined by histopathology, and lung homogenates were inoculated onto cell cultures for virus isolation. There were no calves persistently infected with BVDV detected in the study, as no animals were viremic on day 0, nor were any animals viremic at the 2 subsequent serum collections. There were, however, 4 animals with BVDV type 1 noncytopathic (NCP) strains in the sera from subsequent collections. Viruses were isolated from 9 lungs: 7 with PI-3V, 1 with NCP BVDV type 1, and 1 with both BVHV-1 and BVDV. The predominant bacterial species isolated from these lungs was Pasteurella haemolytica serotype 1. There was serologic evidence of infection with BVDV types 1 and 2, PI-3V, and BRSV, as noted by seroconversion (> or = 4-fold rise in antibody titer) in day 0 to day 34 samples collected from the 104 survivors: 40/104 (38.5%) to BVDV type 1; 29/104 (27.9%) to BVDV type 2; 71/104 (68.3%) to PI-3V; and 81/104 (77.9%) to BRSV. In several cases, the BVDV type 2 antibody titers may have been due to crossreacting BVDV type 1 antibodies; however, in 7 calves the BVDV type 2 antibodies were higher, indicating BVDV type 2 infection. At the outset of the study, the 120 calves were at risk (susceptible to viral infections) on day 0 because they were seronegative to the viruses: 98/120 (81.7%), < 1:4 to BVDV type 1; 104/120 (86.7%) < 1:4 to BVDV type 2; 86/120 (71.7%) < 1:4 to PI-3V; 87/120 (72.5%) < 1:4 to BRSV; and 111/120 (92.5%) < 1:10 to BHV-1. The results of this study indicate that BVDV types 1 and 2 are involved in acute respiratory disease of calves with pneumonic pasteurellosis. The BVDV may be detected by virus isolation from sera and/or lung tissues and by serology. The BVDV infections occurred in conjunction with infections by other viruses associated with respiratory disease, namely, PI-3V and BRSV. These other viruses may occur singly or in combination with each other. Also, the study indicates that purchased calves may be highly susceptible, after weaning, to infections by BHV-1, BVDV types 1 and 2, PI-3V, and BRSV early in the marketing channel.

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PubMed1999

Nested reverse transcriptase-polymerase chain reaction (RT-PCR) for typing ruminant pestiviruses: bovine viral diarrhea viruses and border disease virus.

A nested reverse transcription (RT) polymerase chain reaction (PCR) assay was evaluated for differentiating reference bovine viral diarrhea virus (BVDV) strains, BVDV from diagnostic accessions, modified-live virus (MLV) BVDV strains in bovine viral vaccines, and a reference border disease virus (BDV). The detection level of this assay was compared to viral infection in cell culture. The PCR assay was used to distinguish 3 ruminant pestiviruses, types 1 and 2 BVDV, and type 3 BDV. The consensus (first) PCR assay detected all 3 ruminant pestiviruses, a result of the shared sequence homology. The consensus PCR product was subjected to a second (nested) PCR which used type-specific primers. The nested PCR was able to differentiate the 3 ruminant pestiviruses. Viral stocks of BVDV were diluted 10-fold and processed for the 2-step PCR assay. The sensitivity of this 2-step PCR assay was compared to viral infectivity in cell culture based on identical volumes of the system tested (cell culture assay and processing for RNA). The RT-PCR type-specific assay differentiated BVDV laboratory reference strains (12), diagnostic laboratory isolates (15), 2 MLV BVDV vaccine strains, and a BDV strain. The 30 ruminant pestiviruses typed included: (1) 27 reference strains and diagnostic laboratory isolates; 18 cytopathic (CP) type 1 strains, 3 CP type 2 strains, 3 noncytopathic (NCP) type 1 strains, and 3 NCP type 2 strains; (2) 2 MLV strains, type 1; and (3) 1 CP BDV type 3. The PCR assay had a detection limit of 10 TCID50/0.025 mL of virus when 3 separate BVDV were tested. This 2 step RT-PCR assay would be useful for the typing of ruminant pestiviruses, particularly BVDV isolates from the diagnostic laboratory.

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PubMed1998

Duration of serum antibody responses following vaccination and revaccination of cattle with non-living commercial Pasteurella haemolytica vaccines.

This study was designed to determine the duration of serum antibody responses to Pasteurella haemolytica whole cells (WC) and leukotoxin (LKT) in weanling beef cattle vaccinated with various non-living P. haemolytica vaccines. Serum antibodies to P. haemolytica antigens were determined periodically through day 140 by enzyme-linked immunosorbent assays. At day 140, cattle were revaccinated, and antibody responses periodically determined through day 196. Three vaccines were used in two experiments (A and B), OneShot, Presponse HP/tK, and Septimune PH-K. In general, all three vaccines between 7 and 14 days induced antibody responses to WC after vaccination. Antibodies to LKT were induced with OneShot and Presponse. Revaccination at days 28 and 140 usually stimulated anamnestic responses. Serum antibodies to the various antigens remained significantly increased for up to 84 days after vaccination or revaccination. The intensity and duration of antibody responses were variable depending on the experiment and vaccines used. Vaccination with OneShot usually stimulated the greatest responses to WC. Vaccination with OneShot or Presponse resulted in equivalent primary anti-LKT responses. In experiment B, spontaneous seroconversion was found in numerous calves on day 112. Revaccination of those cattle at day 140 resulted in markedly variable antibody responses such that several groups had no increase in antibody responses.

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PubMed1997

Neutralizing antibodies to type 1 and 2 bovine viral diarrhea viruses: detection by inhibition of viral cytopathology and infectivity by immunoperoxidase assay.

Neutralizing antibodies to type 1 and 2 bovine viral diarrhea virus (BVDV) strains were measured by a microtiter virus neutralization test (MVNT) in cell culture. Antibodies (neutralizing) were detected by inhibition of viral infectivity, by the absence of viral cytopathology for cytopathic strains, or by immunoperoxidase staining for noncytopathic strains. The immunoperoxidase-stained monolayers could be detected without the aid of light microscopy. Twenty BVDV strains were used as challenge viruses in the in vitro MVNT, including 14 type 1 and 6 type 2 strains. Representative noncytopathic and cytopathic strains of both types were used. Positive control serum samples available for diagnostic testing contained both type 1 and type 2 BVDV antibodies. There did not appear to be major differences in antibody titers among the respective type strains, regardless of biotype (cytopathic or noncytopathic). In a study with sera from calves receiving a modified live virus or inactivated BVDV vaccine, the calves receiving type 1 strains responded with higher antibody titers to type 1 strains than to type 2 strains.

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PubMed1997

Microtiter virus isolation and enzyme immunoassays for detection of bovine viral diarrhea virus in cattle serum.

Cattle immunotolerant to and persistently infected (PI) with bovine viral diarrhea (BVD) virus (BVDV) constitute the mechanism by which BVDV persists in cattle herds. Two procedures for using serum to detect PI cattle were developed and evaluated. BVDV was found to remain viable for 7 days in serum samples stored at room temperature. The tests use cell culture virus isolation (VI) in 96-well microtiter plates, followed by immunostaining of cell monolayers with monoclonal antibodies. One technique, the immunoperoxidase monolayer assay (IPMA), forms a red intracellular precipitate while the other, the monolayer enzyme-linked immunosorbent assay (M-ELISA) produces a yellow color in solution. The optimal incubation period for microtiter VI was determined to be 4 days. Optimal IPMA staining was obtained by fixing cell monolayers with 20 to 30% acetone, whereas a simple dry-rehydrate-dry cycle provided optimal M-ELISA staining. The M-ELISA and IPMA had the same sensitivities and specificities, but the M-ELISA was a more rapid procedure and use of a spectrophotometer for reading samples allowed for greater objectivity. When compared to standard VI with routine samples submitted for the diagnosis of BVD, M-ELISA and IPMA had a relative sensitivity of 85% and a relatively specificity of 100%. When only samples from cattle suspected of being PI were considered, these two parameters were 100% for both IPMA and M-ELISA. The two procedures, especially the M-ELISA, are suitable for whole-herd testing to identify PI cattle. The appeal of these tests is derived from the convenience of using serum as a diagnostic sample and the ability to rapidly screen large numbers of samples at low cost.

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PubMed1995

Antibody responses by cattle after vaccination with commercial viral vaccines containing bovine herpesvirus-1, bovine viral diarrhea virus, parainfluenza-3 virus, and bovine respiratory syncytial virus immunogens and subsequent revaccination at day 140.

Calves were vaccinated with four different commercial viral vaccines containing bovine herpesvirus-1 (BHV-1), bovine viral diarrhea (BVDV), parainfluenza-3 virus (PI-3V), and bovine respiratory syncytial virus (BRSV) immunogens. For the initial vaccination certain vaccines were given twice (days 0 and 28), whereas other vaccines were given on day 0. The calves received another injection on day 140 with the vaccine originally given on day 0. The sera were collected at days 0, 7, 14, 21, 28, 42, 56, 84, 112, 140, 154, 168, and 196 and assayed for viral neutralizing antibodies. The calves were seronegative to BHV-1, BVDV, and BRSV at the onset of the experiment; however, the calves were PI-3V antibody positive due to prior active infection. The commercial vaccines were: (I) inactivated; (II) modified live virus (MLV); (III) combination of chemically altered live virus, MLV, and inactivated virus; and (IV) combination of inactivated and MLV. Among the vaccine groups there were differences in onset and duration of antibodies as measured by geometric mean titers to each immunogen in postvaccination collection dates compared to day 0 titers; and likewise compared to day 140 titers after revaccination at day 140. There were also differences in antibody titers to the various viruses among the vaccine groups on specific collection dates. All four vaccines induced increased BHV-1 antibodies by day 14 after the initial injection. The antibody titers induced by MLV BHV-1 and the chemically altered BHV-1 vaccines had greater duration than those induced by the inactivated vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Action of quail and chicken interferons on a quail cell line, QT35.

Production of interferon (IFN) in quail cells (QT35) and the activity of quail IFN and heterologous avian IFN (chicken) on QT35 cells were examined. Quail cells produced IFN after induction by bluetongue virus serotype 10; chicken and quail IFN conferred antiviral resistance on the quail cells. Both chicken and quail IFN induced increased levels of 2',5'-oligoadenylate synthetase (2',5'-OAS) in QT35 cells and reduced levels of intracellular Salmonella typhimurium postchallenge. These results indicate that the quail cells produce IFN and respond to homologous and heterologous avian IFN as evidenced by enhanced (1) resistance to viral infection, (2) production of 2',5'-OAS, and (3) resistance to invasion by bacteria. QT35 quail cell monolayer cultures offer an alternative to primary chicken embryo fibroblasts cultures used for avian IFN studies.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Vaccination of cattle with outer membrane protein-enriched fractions of Pasteurella haemolytica and resistance against experimental challenge exposure.

Administration of an N-lauroylsarcosine-derived outer membrane protein fraction of Pasteurella haemolytica A1 (SCI-1) induced a protective response in calves against intrathoracic challenge exposure with the homologous serovar. Outer membrane proteins from heterologous serovars, A6 and A9, induced partial protection that was associated with their respective similarities to serovar A1 in outer membrane protein profiles derived by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Calves vaccinated with SCI preparations did not have detectable neutralizing antibody to P haemolytica A1 leukotoxin. Antibodies to whole-cell antigens, carbohydrate-protein subunit antigen, and SCI-1 were associated with resistance, which indicates that protein antigens shared among cell surface, carbohydrate-protein subunit, and SCI preparations are immunogenic and enhance resistance to experimental challenge exposure.

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PubMed1993

The use of interferon modulates the negative effects of heat stress on poultry production.

A trial was conducted with broilers reared in two temperature environments; one was thermoneutral and the other had cycling ambient temperatures. Human interferon alpha (HuIFN-alpha) was added to the drinking water daily at four dose levels (0.0, 0.01, 0.1 and 1.0 international units (IU) per ml of drinking water). The trial began with 21 day old chicks housed either in a thermoneutral (24 degrees C) or a cycling ambient temperature (24-36 degrees C) environment. Interferon added to water at the highest concentration (1.0 IU/ml) improved surviability of birds in the cycling ambient temperature (24-36 degrees C) environment (P < 0.05). Birds housed in the cycling (24-36 degrees C) environment, drinking the lowest concentration of IFN-alpha 0.01 IU/ml, had a significantly improved weight gain-to-feed ratio. Oral IFN-alpha reduced the cost of production for birds reared in a cycling ambient temperature environment.

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PubMed1993

Isolation and characterization of encephalitic bovine herpesvirus type 1 isolates from cattle in North America.

Nine CNS bovine herpesvirus type 1 (BHV-1) isolates, recovered from bovine brain samples submitted to the Texas Veterinary Medical Diagnostic Laboratories from 1974-1989, were compared by analyzing their DNA restriction endonuclease (RE) fragment migration pattern. Seven had pattern similar to that of the respiratory BHV-1 Cooper strain. The remaining 2 isolates, however, had variant patterns, similar to that of each other, but completely different from patients for the other 7. The RE patterns of these 2 variants were similar to published RE patterns for 2 encephalitic or neuropathogenic BHV-1 strains--the Australian N-569 strain and the Argentine A-663 strain. One of the Texas encephalitic variants (No. 30326) was isolated from the CNS of a calf that died during an epizootic of encephalitis in 1974. The other, designated TX-89, was isolated in 1989 from the CNS of a 7-month-old feedlot steer with acute fatal encephalitis. Microscopic lesions of encephalitis with neuronal degeneration and intranuclear inclusions were observed for 3 of the 9 isolates, the 2 variant isolates (No. 30326 and TX-89), and a respiratory isolate. The remaining 6 CNS isolates, all respiratory subtypes, were recovered from cattle that did not have clinical CNS disease or gross or microscopic CNS lesions; in 5 of these cattle, virus was recovered from at least 1 other organ (lungs) besides the CNS. We conclude that the CNS of calves can be naturally infected with 2 distinct BHV-1 subtypes, the respiratory and the encephalitic, and that the encephalitic subtype (subtype 3 or BHV-1.3) has been present in Texas cattle since at least 1974.

Animals↗
PubMed1993

Fluorometric measurement of IgG antibody responses in cattle vaccinated with Tritrichomonas foetus.

A photometrically-measured indirect fluorescent antibody (IFA) test was developed to measure antibody levels in three heifers vaccinated intramuscularly with two injections (two-week interval) of a vaccine containing formalin-killed Tritrichomonas foetus in oil adjuvant; a separate animal served as a nonvaccinated control. Sera were collected weekly and tested for specific IgG against T. foetus. Antibodies were detectable within two weeks of the initial injection and reached reciprocal titers as high as 7700 as estimated from previously tested reference sera. Titers peaked at six to eight weeks and remained at relatively high levels for the eleven-week study period. The fluorometric assay was easily developed and economical to perform; in addition, it more accurately estimated IgG levels than standard slide IFA tests.

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