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Biomedical subjects

D G Bryson

Publications and source records attributed to D G Bryson.

51 records · Page 3Linked to original sources
PubMed1983

Respiratory syncytial virus pneumonia in young calves: clinical and pathologic findings.

Nine young calves given respiratory syncytial virus by a combined intranasal and intratracheal route developed a severe respiratory tract disease in which coughing, tachypnea, and hyperpnea were prominent clinical features. Calves were euthanatized on postinoculation (initial) days (PID) 1 to 13. At necropsy, large areas of consolidation were present in the cranial, middle, accessory, and cranial parts of the caudal lung lobes of calves killed between PID 4 and 13. Histopathologic examination revealed widespread and severe lesions in small bronchi, bronchioli, and alveoli. Multinucleate epithelial syncytia on bronchiolar and alveolar walls, many containing eosinophilic intracytoplasmic inclusion bodies, were present in the lungs of calves killed on PID 4, 5, and 6. Necrosis and epithelial loss, hyperplasia, and metaplasia were also observed in the epithelium of small bronchi and bronchioli. The lumina of these airways were occluded to varying degrees with exudate. Exudate was present within alveoli, and interalveolar septa were markedly thickened. Collapse of the thickened septa produced large areas where alveolar air spaces were totally obliterated. Repair was evident in the lungs of calves killed at PID 10 and 13 with reepithelialization of damaged bronchiolar mucosa, organization of bronchiolar exudate leading to bronchiolitis obliterans, and peribronchial and peribronchiolar fibrosis. Inoculation of 3 calves by an intranasal route alone produced a less severe clinical disease with only minimal lesions present at necropsy.

Animals↗
PubMed1979

Observations on outbreaks of respiratory disease in calves associated with parainfluenza type 3 virus and respiratory syncytial virus infection.

In four outbreaks of indoor calf pneumonia, dyspnoea was a prominent clinical finding. At necropsy it was associated with pneumonia involving the cranial lobes of the lung and severe pulmonary emphysema. Histological examination of lung tissue revealed bronchiolitis and alveolitis with alveolar epithelial cell hyperplasia and multinucleate syncytium formation. Intraalveolar haemorrhage, intra-alveolar oedema and hyaline membrane formation were also noted. In all cases parainfluenza type 3 (PI3) virus was isolated from the lungs. In each of the four outbreaks there was evidence of PI3 virus and respiratory syncitial virus (RSV) infection.

Animals↗
PubMed1978

Observations on outbreaks of respiratory disease in housed calves--(2) Pathological and microbiological findings.

Extensive pneumonic lesions were present in 42 out of 43 calves obtained for post mortem examination from 34 outbreaks of respiratory disease in Northern Ireland. Bronchiolitis and alveolitis with necrosis of bronchiolar mucosa which progressed to bronchiolitis obliterans and peribronchiolar fibrosis were prominent histopathological features in the lungs of calves obtained live. The majority of calves which died within the first two months of these outbreaks had severe exudative bronchopneumonia with marked vascular damage and necrosis of pulmonary parenchyma. Pasteurella spp, Mycoplasma spp and P13 virus were the organisms most frequently recovered from the pneumonic lungs.

Animals↗
PubMed1978

Observations on outbreaks of respiratory disease in housed calves--(1) Epidemiological, clinical and microbiological findings.

In 47 of 50 outbreaks of respiratory disease in indoor calves which had never been to grass there was clinical evidence of pneumonia in all animals examined. Calf housing was in most cases considered unsatisfactory. Virus activity was detected in 70 per cent of outbreaks investigated within a few days post onset of respiratory signs. Parainfluenza (PI) 3 and respiratory syncitial virus (RSV) were the viruses most frequently involved. In the majority of outbreaks Mycoplasma species and Pasteurella multocida were present in the upper respiratory tract of affected calves.

Animals↗
PubMed1976

Studies on rotavirus infection and diarrhoea in young calves.

The occurrence of diarrhoea in calves was monitored during the first three weeks of life. Calves fed amounts of colostrum sufficient to produce serum Ig levels in excess of 30 mg per ml did not develop diarrhoea, whereas calves fed less colostrum did. Rotaviruses and mycoplasma-like particles were observed in the faeces of calves with and without diarrhoea. The epidemiology of rotavirus infection in calves is discussed.

Animals↗
PubMedDate not supplied

Evaluation of a competitive immunoassay for the detection of bovine haptoglobin.

A competitive immunoassay to quantify the serum concentration of bovine haptoglobin (hp) using time resolved fluorescence was compared with an indirect method of hp assay (haemoglobin binding assay), using sera taken from healthy animals (n = 158), animals experimentally infected with Haemophilus somnus (n = 10) and from sick animals requiring veterinary treatment (n = 440). Upper limits of normality (for normal animals) were tentatively established for the immunoassay (2.1 micrograms ml-1) and for the haemoglobin binding assay (103 micrograms ml-1). The competitive immunoassay detected elevated hp in 62.5 per cent of field sera by comparison with only 19.2 per cent using the conventional haemoglobin binding assay. Serum albumin concentration did not correlate with hp although concentrations of globulins and copper did correlate. However, these parameters (serum globulin and copper) were found to be insensitive markers of inflammatory disease.

Acute-Phase Reaction↗
PubMedDate not supplied

The experimental production of pneumonia in calves by intranasal inoculation of parainfluenza type III virus.

Thirteen colostrum deprived calves were inoculated with a low passage field strain of parainfluenza type III (PI 3) virus. Virus was administered by the intranasal route and the calves were experimentally infected twice daily for four consecutive days. Clinical signs of respiratory disease were noted and pneumonia was present in 12 animals at necropsy. PI 3 virus was isolated from the lung lesions and no other respiratory pathogens could be demonstrated. The pneumonic lesions grossly, histologically and in their distribution resembled those encountered in naturally occurring outbreaks of indoor calf pneumonia.

Animals↗