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Title: Epidemiological features of porcine proliferative enteropathy
Author: Smith, Sionagh Helen
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1997
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The polymerase chain reaction (PCR) assay was adapted and optimised for specific detection of Lawsonia intracellularis genomic DNA segment in swine faeces. Lawsonia intracellularis is the aetiological agent of porcine proliferative enteropathy (PPE) and the PCR represents the first diagnostic test suitable for ante-mortem use in affected swine. Various methods designed to extract bacterial DNA from faeces were evaluated to establish a convenient and optimum protocol. The PCR was utilised in pig challenge studies to investigate the excretion patterns of L. inracellularis in weaner pigs orally inoculated with pure cultures of L. intracellularis. This challenge work demonstrated that the PCR was a suitable tool for detection of infection, and indicated that individual animals could excrete L. intracellularis organisms for periods of up to ten weeks post-challenge. Such an excretion period has major implications for the transmission of organisms in the field. For example, if infected growers are still shedding L. intracellularis organisms upon entry to the breeding population, then this is a possible route for the transmission of disease to younger, susceptible pigs. A more extensive, two-part investigation of the epidemiological aspects of PPE in the field followed. The investigation comprised a farm sampling study and a questionnaire postal survey. In the farm sampling study, faeces samples were collected serially over a ten month period from breeding gilts and their litters. Samples were subjected to PCR for the detection of infection, allowing estimation of within-herd prevalence, as well as determination of possible transmission patterns. The assay successfully detected the presence of L. intracellularis in the weaners and/or growers of three of the five farms selected for this study. The within-herd prevalence for these age-groups ranged from 10 to 30%. The PCR also confirmed infection in several of the adult breeding boars and gilts.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available