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Title: The use of experimental infection models to investigate the correlation between clinical and pathological measures of the severity of respiratory disease in three species
Author: Reeve-Johnson, L.
ISNI:       0000 0004 2686 4333
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1999
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The objective of this research was to investigate the relationship between ante mortem assessments of disease severity and the gross pathological manifestations of disease observed during necropsy. Many clinical assessments are subjective, the hypothesis under investigation is that these correlate with the pathological progression of the disease in the animal. Bronchopneumonia due to Pasteurella haemolytica A1 in calves, Actinobacillus pleuropneumoniae infection in pigs, and Mycoplasma gallisepticum infection of chickens were investigated. The diseases were induced by experimental infection and animals were closely monitored. Both graphical and statistical methods were used to correlate ante mortem measures of disease severity with each other and with post mortem measures of gross pathological lesions and bacteriological isolation of the infecting organism. Calves showed highly correlated relationship between ante mortem and post mortem indicators of disease severity. For pigs, the relationship between clinical variables and gross pathology was much less clear and varied between the three serotypes of Actinobacillus pleuropneumoniae used (serotypes 3, 5a, 9). In chickens, there were few clinical signs evident until the pathology compromised the physiological reserve capacity of the airsacs. Beyond this "threshold", rapid increases in respiratory auscultation score, mycoplasma isolation and serological response were all indicators of increasing gross pathological changes. The relationships between ante mortem assessments of disease severity and the gross pathological lesions recorded at necropsy were usually non-linear and differed for each pair of variables correlated. The relationships between clinical variables being used as indicators of disease severity and the post mortem pathological measures need to be clearly understood for each variable before conclusions concerning the disease severity, prognosis or, in treated animals, efficacy predictions can be made.
Supervisor: Not available Sponsor: Not available
Qualification Name: Not available Qualification Level: Doctoral
EThOS ID:  DOI: Not available