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Biomedical subjects

E J Stott

Publications and source records attributed to E J Stott.

At least 73 records · Page 4Linked to original sources
PubMed1982

A search for new microorganisms in calf pneumonia by the inoculation of gnotobiotic calves.

In a detailed microbiological and pathological study of eight outbreaks of calf pneumonia, which included the inoculation of respiratory material into 18 gnotobiotic calves, a total of five viruses, four species of mycoplasma and 19 species of bacteria were identified. The only microorganism not previously associated with bovine respiratory disease was a coronavirus. The experimental disease produced in the majority of the gnotobiotic calves by the intratracheal inoculation of unpassaged respiratory material, closely resembled the natural disease. However statistical analysis of the results could not ascribe the disease seen to a single microorganism or to a particular combination of microorganisms. Assuming therefore that no microorganisms were missed in the study, it was concluded that the microbiological cause of the experimental disease lay amongst the organisms already found and that one or more of three other factors, discussed in the paper, accounted for the experimental disease produced.

Animals↗
PubMed1981

Diagnosis of respiratory syncytial virus infection in the bovine respiratory tract by immunofluorescence.

Direct staining of nasopharyngeal smears with hyperimmune bovine serum raised against respiratory syncytial virus (RSV) and conjugated with fluorescein isothyocyanate was compared with virus isolation from 14 experimentally infected animals. Twenty-four out of 107 specimens examined were positive by the fluorescent antibody (FA) method and 21 out of 107 by virus isolation. Most of the FA positives (81 per cent) were detected after the ninth day of infection whereas 80 per cent of virus isolations were made before this time. Only one false positive (one out of 57 specimens) was detected by the FA method in nine uninfected control animals. Non-specific fluorescence presented some problems when examining nasopharyngeal material. The same conjugate was found to be more useful in detecting RSV antigen in lung tissue of eight experimentally infected animals and 11 out of 22 naturally occurring cases of calf pneumonia from five outbreaks of disease. In three of the outbreaks the diagnosis was confirmed by virus isolation and serology. The dominating histopathological response in both the experimental and the natural disease was an acute bronchiolitis and alveolitis. The finding of RSV antigen in association with these lesions provides further evidence for the role of RSV as a respiratory pathogen of cattle.

Animals↗
PubMed1981

A reverse passive haemagglutination test for the detection of respiratory syncytial virus in nasal secretions from infants.

A reverse passive haemagglutination (RPH) test has developed for the detection of respiratory syncytial (RS) virus in nasal secretions, taken from infants with acute respiratory illness. In the final form of the procedure, RS virus was detected in 24 of 25 samples positive for RS virus by tissue culture and/or fluorescence antibody staining and in two samples negative for RS virus by these techniques. The simplicity of the technique and the rapidity with which it may be performed together with its apparently high degree of sensitivity should make RPH useful in the rapid diagnosis of RS virus.

Hemagglutination Tests↗
PubMed1980

The possible role of respiratory syncytial virus and Pasteurella spp in calf respiratory disease.

In a natural outbreak of respiratory disease during 1976, 31 of 43 calves showed moderately severe clinical signs which included pyrexia (maximum 42 degrees C) and tachypnoea. During the outbreak infection by respiratory syncytial virus (RSV) was demonstrated by isolation from nasopharyngeal swabs or by serology. Pasteurella haemolytica or P multocida were isolated from the blood of four and five calves respectively. In the month before disease 65 per cent of the calves showed significant antibody responses to P haemolytica. However a similar serological response to P haemolytica was demonstrated during 1975 in a comparable group of calves in which no disease and no infection with RSV was detected. No serological response to P multocida was demonstrated in either year. The temporal correlation of RSV infection with respiratory disease in the group of 43 calves was striking but the evidence neither reinforced nor discounted the possibility of interaction between RSV and P haemolytica infection in the pathogenesis of disease.

Animals↗
PubMed1980

Experimental infection of calves with two strains of bovine virus diarrhoea virus: certain immunological reactions.

Certain immunological responses of 4-6 month old calves experimentally inoculated with either cytopathic or non-cytopathic bovine virus diarrhoea virus (BVDV) were compared with those of uninfected control calves. The tests used to demonstrate the immunological responses were the transformation of lymphocytes by PHA mitogen, the percentage of lymphocytes with surface immunoglobulin, and the antibody titres induced by an intravenous inoculation of killed Brucella abortus. There were no significant differences between the two groups of calves and therefore, the mild experimental disease produced by BVDV did not appear to affect adversely the immunological response.

Animals↗
PubMed1980

A survey of virus infections of the respiratory tract of cattle and their association with disease.

A total of 1590 caves were investigated between May 1972 and December 1975. Twenty-two per cent were treated for respiratory disease and 2 . 5% died of pneumonia. Almost 80% of the respiratory illness occurred in six sharp outbreaks. Samples of virology were collected routinely from 127 healthy calves and from 354 calves treated for respiratory signs and comprised 1143 nasopharyngeal swabs and 1069 sera. Virus infections were detected on 540 occasions including 135 by parainfluenzavirus type 3 (Pi-3), 78 by respiratory syncytial virus (RSV), 103 by rhinovirus, 49 by bovine virus diarrhoea virus (BVDV), 29 by adenoviruses, 53 by reoviruses and 88 by enteroviruses. The seasonal and age distribution of infections differed between viruses. Only infections by RSV, Pi-3 and BVDV were significantly associated with disease.

Adenoviridae Infections↗
PubMed1980

Experimental infection of calves with two strains of bovine virus diarrhoea virus: virus recovery and clinical reactions.

Fifteen calves were inoculated with a mixture of two strains of bovine virus diarrhoea virus (BVDV), the cytopathogenic NADL strain which had been passaged over 20 times n vitro, and the non-cytopathogenic FCS strain, passaged only once after isolation from fetal calf serum. In a second experiment, seven calves received the NADL strain, and eight the FCS strain. The clinical and virological results of the two experiments were compared. In dual infections, the NADL strain interfered with the replication of the FCS strain resulting in less severe disease than the FCS strain alone. The FCS-BVDV was recovered from nasopharyngeal swabs and buffy coat cells whereas the NADL-BVDV was recovered only from nasopharyngeal swabs. The cytopathogenicity of the two strains did not change after passage in vivo. The differences observed are discussed in relation to cultural history and cytopathogenicity.

Animals↗
PubMed1979

The response of bovine lymphocytes from lymph and blood to phytohaemagglutinin.

Optimal conditions for stimulation of bovine lymphocytes by Phytohaemagglutin (PHA) were established in a microtitre assay. Lymphocytes from efferent duct lymph responded vigorously, with specific incorporation of 100,000 to 200,000 cpm/well, providing the conditions of cell culture are carefully controlled. Peripheral blood lymphocytes responded over a wider range of cultural conditions but optimal specific incorporation was usually only 40-100,000 cpm/well.

Animals↗
PubMed1978

The effect of pneumonia induced in mice with Mycoplasma pulmonis on resistance to subsequent bacterial infection and the effect of a respiratory infection with Sendai virus on the resistance of mice to Mycoplasma pulmonis.

The effect of pneumonia induced by Mycoplasma pulmonis in mice on the resistance of the lung to additional bacterial infection was examined. The effect of pneumonia induced by Sendai virus on the resistance of mice to M. pulmonis was also investigated and compared with the effect of Sendai virus on resistance to Staphylococcus aureus. Sendai virus infection decreased subsequent resistance to M. pulmonis in proportion to the virus dose. Decreased resistance to subsequent S. aureus and M. pulmonis infection was greatest at about the same time after inoculation of virus and was related to virus-induced lesions. Besides affecting the resistance of mice to subsequent mycoplasma infection, Sendai virus could enhance an existing mycoplasma infection. Pneumonia induced by M. pulmonis did not decrease resistance to subsequent bacterial infection. The mechanism whereby Sendai virus decreases host resistance is therefore similar for bacteria and mycoplasmas, but pneumonia induced by mycoplasmas does not have the same effect.

Animals↗
PubMed1978

An inactivated parainfluenza virus type 3 vaccine: the influence of vaccination regime on the response of calves and their subsequent resistance to challenge.

Calves maintained in insolated pens were vaccinated with an inactivated parainfluenza virus type (3) (pi3) vaccine usingparenteral and local route singly and in combination. The calves were subsequently monitored for serum antibody response and challenged intranasally with live virus to assess the protection derived from vaccination. Calves receiving one subcutaneous dose of vaccine in oil adjuvant produced a marked antibody response and were partially protected against challenge. Those receiving two successive subcutaneous doses produced a much greater antiboyd response and were completely protected against challenge. One intranasal dose of aqueous vaccine failed elicit a significant serum antibody response or protection against challenge. However, there was some evidence that intranasal vaccination following a single subcutaneous vaccination produced more effective immunity than one subcutaneous dose alone. Thus a vaccination regime was established which protected calves against experimental challenge and which could thefore be used in the field to assess the role of Pi3 virus in calf respiratory disease.

Administration, Intranasal↗
PubMed1977

The effect of temperature on the synthesis of rhinovirus type 2 RNA.

The reduced yields of rhinovirus type 2 at temperatures above 37 degrees C were shown to result from the degradation of virus-induced RNA, leaving little RNA available for inclusion into mature infectious virions. The degradation occurred about 6 h p.i., and appeared to be selectively effecting the single-stranded species. Lysosomal nucleases do not appear to have a role in this supra-optimal degradation.

RNA, Viral↗
PubMed1977

Interactions between calf alveolar macrophages and parainfluenza-3 virus.

Cells washed from the lungs of freshly killed calves (lung wash cells; LWC) were cytotoxic for calf kidney (CK) target cells infected with parainfluenzavirus type 3 (Pi-3) when assayed by chromium release. LWC collected from 25 calves, including two gnotobiotic animals that had not previously been infected with Pi-3, were all cytotoxic, giving a specific chromium release between 11 and 50%. Cytotoxicity was detected at ratios of LWC to target cell as low as 5:1. The cytotoxic reaction required viable LWC, was inhibited by Pi-3 antiserum, and was not the result of virus-induced damage to the target cells. The cytotoxic cells in the LWC population were identified as alveolar macrophages from observations on glass adherence, phagocytic activity, killing by silica and fine-structural appearance. When LWC were added to CK cells or organ cultures of bovine trachea infected with Pi-3, the yield of virus was reduced for the first 2 to 3 days. However, subsequently, Pi-3 virus replicated in the LWC. Infection of LWC with Pi-3 virus reduced their cytotoxic activity. The significance of these interactions between alveolar macrophages and Pi-3 virus is discussed.

Animals↗
PubMed1976

The growth of respiratory syncytial virus in organ cultures of bovine foetal trachea.

Respiratory syncytial (RS) virus grown in organ cultures of bovine foetal trachea at 37 degrees C and pH 7.2 reached maximum titres of up to 1 X 10(5) PFU/ml between 11 and 21 days after inoculation. Virus yield was increased three fold by incubation at 33 degrees C, but depressed by the addition of RS virus antiserum, with or without bovine complement, or by the addition of alveolar macrophages. Variation in pH or the concentration of foetal calf serum and magnesium chloride did not affect the virus yield. Virus growth did not affect ciliary activity of the cultures. Histological changes involved slight flattening of the epithelium and the appearance of phloxinophilic inclusion bodies. Fluorescent antibody staining showed more virus antigen in the peri-tracheal connective tissue than in the ciliated epithelium. The presence of non-cytopathic mucosal disease (MD) virus in RS virus infected organ cultures slightly depressed RS virus growth but did not influence ciliary activity. These in vitro experiments suggest that the tracheal epithelium may not be an important target in the pathogenesis of RS virus infection in vivo.

Animals↗
PubMed1976

Studies of experimental rhinovirus type 2 infections in polar isolation and in England.

After five months of total isolation a wintering party of seventeen British Antarctic Survey (BAS) personnel was inoculated under double blind concitions with placebo, or rhinovirus type 2 which had been propagated in tissue culture. The clinical and virological responses of these subjects were compared with those of volunteers in England who received a similar dose of the same strain. The virus used was apparently partly attenuated for man; at the dosage used its effects in England were similar to a smaller dose of an unattenuated strain, but in the Antarctic it caused relatively severe infections. Both the symptoms and the laboratory evidence of virus infection appeared to be more pronounced in the BAS subjects than in the volunteers in England who received the same challenge. In the former group the infection readily spread to those who were originally given placebo. In the BAS subjects serum antibody titres were well maintained during the isolation period but a significant fall in nasal immunoglobulin concentration was recorded during the 5 months of isolation after the virus challenge. Possible mechanisms for the increased sensitivity to rhinovirus of subjects who have been totally isolated in a small closed community are discussed.

Adult↗
PubMed1976

Experimentally produced calf pneumonia.

Experimental pneumonia was produced in calves by the endobronchial inoculation of pneumonic lung homogenates. Irradiated homogenates produced minimal pneumonia. Ampicillin treatment of the homogenates and the experimental calves reduced the extent of pneumonia. Treatment with tylosin tartrate prevented experimental pneumonia. These results suggest that the total pneumonia was due to organisms susceptible to tylosin tartrate and that the residual pneumonia remaining after ampicillin treatment was due to organisms susceptible to tylosin tartrate but not to ampicillin. Of the organisms isolated from the lungs, the ones in this latter category most likely to be responsible are Mycoplasma dispar and ureaplasmas (T-mycoplasmas).

Acholeplasma laidlawii↗