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Biomedical subjects

G M Robertson

Publications and source records attributed to G M Robertson.

At least 19 recordsLinked to original sources
PubMed1992

Vaccine efficacy for reducing turbinate atrophy and improving growth rate in piggeries with endemic atrophic rhinitis.

Two vaccines, based on formalin-killed whole cells of toxigenic Pasteurella multocida type D and Bordetella bronchiseptica combined with a partially toxoided cell extract of P multocida, were prepared with Freund's incomplete adjuvant (vaccine 1) or by alum precipitation (vaccine 2). Each was tested for safety and efficacy in reducing the severity of nasal turbinate atrophy and improving the growth rate of pigs in three Western Australian commercial piggeries with endemic atrophic rhinitis. In safety experiments with vaccine 1, no adverse clinical effects were observed in vaccinated sows or their progeny. Piglets receiving vaccine 2 showed no injection site abnormalities, pyrexia or turbinate atrophy. In field trials, vaccine 1 significantly reduced the prevalence of moderate to severe nasal turbinate atrophy (Done score 3 to 5) when used in two piggeries (A and B). Progeny from vaccinated sows in piggery B also grew significantly faster than controls. When vaccine 2 was used in piggery A at a later date and in another piggery (C), growth rate was not improved in either piggery and the prevalence of moderate to severe turbinate atrophy was reduced only in piggery C.

Adjuvants, Immunologic↗
PubMed1991

Use of the enzyme linked immunosorbent assay (ELISA) to detect the IgM and IgG antibody response to Leptospira interrogans Serovar hardjo in pregnant ewes.

Fourteen pregnant ewes were inoculated with Leptospira interrogans serovar hardjo via intramuscular injection or inoculation via the conjunctiva. The serological response to inoculation detected by the microscopic agglutination test was compared to IgM and IgG antibody levels detected by enzyme linked immunosorbent assay. Intramuscular injection produced a better serological response than conjunctival inoculation. The mean IgM response was short lived whereas the IgG antibody response and the MAT persisted for much longer. The IgM antibody levels may be useful as an indicator of recent exposure. Although leptospiruria was not established in any of the animals, 6 of the 14 pregnant ewes failed to rear a healthy lamb.

Agglutination Tests↗
PubMed1988

Vaccination against ovine dermatophilosis.

Zoospore, filamentous and soluble antigens were prepared from Dermatophilus congolensis and examined for their ability to protect sheep from challenge with D. congolensis zoospores. In 1 experiment, sheep were vaccinated with Antigens A, B and C. The number of sheep protected in the group vaccinated with Antigen B was greater (P less than 0.05) than that in the unvaccinated group after challenge. The group vaccinated with Antigen B had a higher antibody response (P less than 0.05) to Antigen B than to Antigen A or C. In a second experiment, 2 groups of sheep were vaccinated with Antigen B. All sheep in this study developed lesions after challenge, but those on the vaccinated sheep were less severe (P less than 0.05) than those on the unvaccinated sheep. The antibody response to Antigen A, 28 days after vaccination, was higher (P less than 0.05) than the response to Antigen B.

Actinomycetales↗
PubMed1987

Serum and skin surface antibody responses in merino sheep given three successive inoculations with Dermatophilus congolensis.

Three antigens prepared from different phases of the life cycle of Dermatophilus congolensis were used in an enzyme-linked immunosorbent assay to measure serum and skin surface antibody responses in sheep after a first, second and third inoculation with D. congolensis. After the first inoculation, a strong antibody response to the flagella, filament and soluble antigens was detected after 7-21 days in the sera from sheep that were regularly biopsied; the antibody response at the skin surface was detected 28-42 days after inoculation, when the lesions were resolving. Strong anamnestic responses were detected in the serum of sheep that were biopsied and some of the nonbiopsied sheep after the second and third inoculations, but the skin surface antibody response at these times was variable.

Actinomycetales↗
PubMed1987

Cellular responses in the skin of merino sheep to repeated inoculation with Dermatophilus congolensis.

The cellular response in the skin of Merino sheep was examined after three successive inoculations with Dermatophilus congolensis. There was a massive neutrophil influx into the infected epidermis and underlying dermis at 4-10 days after the first inoculation. A lymphocyte-macrophage response occurred at 10-12 days, followed by a plasma cell response at 14-38 days. Resolution of skin lesions after the first inoculation corresponded to the time when the plasma cell response in the skin was most intense. A second inoculation with D. congolensis, 70 days after the first, failed to produce skin lesions typical of dermatophilosis. Typical lesions of dermatophilosis did develop after a third inoculation of the same sheep 140 days after the first inoculation, but the lesions resolved in most sheep within 13 days. Dermatophilosis did not develop in some of these sheep at sites inoculated with 100-1000-fold lower infective doses of D. congolensis, whereas control sheep did develop lesions.

Actinomycetales↗
PubMed1986

Use of enzyme immunoassay in a serological survey of leptospirosis in sheep.

A total of 731 serums, all from Merino rams from 20 farms, were tested for antibodies against Leptospira interrogans serovars hardjo, pomona and tarassovi using the microscopic agglutination test (MAT). The enzyme immunoassay (EIA) technique was used to test all serums for IgM and IgG antibodies to serovar hardjo. In the MAT, reactions to serovar hardjo were most common with 236 rams (32.3%) reacting at 1/100 or greater. Only 1.9% of serums reacted against serovar tarassovi and 1.1% against serovar pomona. The percentage of sheep with positive MAT reactions to serovar hardjo ranged from 0 0 to 94.9 between farms. When using EIA, 46 (6.2%) of the serums were positive for IgM antibody and 246 (33.6%) were positive for IgG antibody. Correlation of the EIA for detection of IgG antibody with the MAT was good. The EIA detection of IgG antibody was considered to be a good alternative test to the MAT for epidemiological studies in sheep.

Agglutination Tests↗
PubMed1986

Isolation of toxigenic Pasteurella multocida from an outbreak of atrophic rhinitis in pigs.

An outbreak of severe atrophic rhinitis is described. A toxigenic strain of P. multocida was isolated from one affected pig. Severe turbinate atrophy was not associated with significantly reduced bodyweight gain in a batch of 34 pigs examined at slaughter. The history of the outbreak suggested that pigs recently introduced from overseas may have been the source of the disease.

Animals↗
PubMed1985

The use of the enzyme-linked immunosorbent assay (ELISA) to detect the IgM and IgG antibody response to Leptospira interrogans serovars hardjo, pomona and tarassovi in cattle.

Leptospira interrogans serovars pomona, hardjo and tarassovi were each used to inoculate 6 cattle. Three-hundred and ninety-nine sera collected from the inoculated animals and from a control group over a 3-month period were tested using the microscopic agglutination test (MAT) and the enzyme-linked immunosorbent assay (ELISA). Leptospiruria was monitored by microscopic examination and culture. The ELISA detected specific IgM antibody against the serovars in all infected cattle 1 week after inoculation. This IgM antibody persisted in most of the animals for 3-5 weeks. Specific IgG antibody appeared at the same time or just after IgM, but persisted for much longer. Levels of antibody detected by the ELISA and the MAT did not correlate with each other, nor with the periods of leptospiruria found in the infected cattle.

Agglutination Tests↗
PubMed1983

Detection of leptospires in tissue using an immunoperoxidase staining procedure.

An immunoperoxidase technique for the localisation of leptospires in sections of formalin fixed paraffin embedded kidney tissue is described. The procedure utilises a two-layered antibody sandwich with rabbit anti-leptospiral immunoglobin. Using antiserum to specific leptospiral serovars the presence and distribution of specific serovar in the tissue could be determined. The technique was also used to detect leptospires of given serovars in smears made from infected tissues and fluids. There was good correlation between culture results and results of the immunoperoxidase staining method on kidneys infected with leptospires. The diagnostic possibilities of the technique on formalin fixed tissue specimens are discussed.

Animals↗
PubMed1982

Bovine IgM and IgG response to Leptospira interrogans serovar hardjo as measured by enzyme immunoassay.

The enzyme-linked immunosorbent assay (ELISA) was used to detect specific IgG and IgG antibodies in the sera of cattle infected or immunized with Leptospira interrogans serovar hardjo. IgM appeared first but was quickly followed by IgG which persisted longer than IgM. The levels of antibody detectable by ELISA and by the microscopic agglutination test (MAT) did not correlate, suggesting that the two techniques measured different antigen--antibody systems. The transient nature of the IgM response as measured by ELISA indicates potential usefulness as a serodiagnostic test for detecting current leptospiral infections.

Agglutination Tests↗
PubMed1982

Claimants for mobility allowance: causes of disability and the scope for prevention.

Six hundred and twenty-one claimants for Mobility Allowance were examined by the author, who recorded the patient's statement of his or her history and current disability, carried out a full physical examination and observed the gait and limitation of walking. Four hundred and seventy-five appeared to satisfy the medical conditions to qualify for the allowance. They were analysed by age, sex and body system involved and were compared with the corresponding total figure for Mobility Allowance in England, Scotland and Wales.The more common diagnoses are listed and are considered from the point of view of prevention. The implications for general practice are discussed. They concern the detection of hypertension and health education for antenatal care, smoking and the wearing of seat belts.

Adult↗
PubMed1981

Replication of infectious laryngotracheitis virus in chickens following vaccination.

The site of replication of infectious laryngotracheitis vaccine virus (ILTV) was studied in chickens vaccinated by drinking water (DW), intraconjunctival (IC) and cloacal (CL) routes. The anatomical sites exposed to vaccine were determined by simulating vaccination with rhodamine red dye. Virus replication was determined by recovering virus from various organs at necropsy. The dye simulation studies clearly demonstrated that DW vaccination did not usually expose susceptible target organs to virus while the CL and IC routes flooded susceptible organs with vaccine. Virus replication was confined to the cloaca in CL vaccination birds while in IC and DW vaccination birds most replication took place in the nasal cavity. Vaccine virus did not always become established in DW vaccinated birds and its establishment did not appear to be related to the amount of vaccine these birds were exposed. It was concluded that DW vaccination depends for its success upon the accidental contamination of the nasal cavity with vaccine virus during the act of drinking.

Animals↗
PubMed1981

The effect of challenge with virulent Brucella abortus on beef cattle vaccinated as calves or adults with either Brucella abortus strain 19 or 45/20.

Groups of female calves were vaccinated subcutaneously with the standard dose of Brucella abortus strain 19 (S19) or with B. abortus 45/20 (S45/20). These calves and non-vaccinated control calves were mated at 15 months of age and challenged by way of the conjunctival sac with B. abortus strain 544 (S544). The incidence of abortion, stillbirths, weanling calves and healthy calves was observed after challenge and specimens were collected for culture at parturition and slaughter. Fifteen healthy calves were born to 18 animals vaccinated with S19, 12 were born to 18 animals vaccinated with S45/20 and 2 were born to 8 animals that were not vaccinated. B. abortus was isolated from 5 of the animals vaccinated with S19, 13 of the animals vaccinated with S45/20 and 9 of the 12 animals that were not vaccinated. Only one of the 5 infected animals vaccinated with S19 was vaccinated as an adult.

Animals↗
PubMed1981

The association between body strike and dermatophilosis of sheep under controlled conditions.

The association of dermatophilosis with body strike of sheep caused by Lucilia cuprina was studied in a controlled environment. When sheep with areas of wet normal fleece and areas of wet fleece containing scabs induced by infection of the skin with Dermatophilus congolensis were exposed to gravid L. cuprina the files oviposited only on dermatophilosis-affected areas. In wet dermatophilosis-affected fleece, naturally oviposited L. Cuprina eggs hatched and the larvae developed to the second instar stage. Artificially implanted L cuprina eggs hatched in both wet dermatophilosis-affected fleece and wet normal fleece. In wet dermatophilosis-affected fleece the larvae from implanted eggs developed normally but in wet normal fleece they did not develop past the first instar stage. It was concluded that wet but otherwise uncomplicated dermatophilosis lesions are attractive to L. cuprina and provide sufficient protein to allow larval development to take place.

Actinomycetales Infections↗