Experimental Actinobacillus pleuropneumoniae challenge in swine: Comparison of computed tomographic and radiographic findings during disease

Abstract

BackgroundIn pigs, diseases of the respiratory tract like pleuropneumonia due to Actinobacillus pleuropneumoniae (App) infection have led to high economic losses for decades. Further research on disease pathogenesis, pathogen-host-interactions and new prophylactic and therapeutic approaches are needed. In most studies, a large number of experimental animals are required to assess lung alterations at different stages of the disease. In order to reduce the required number of animals but nevertheless gather information on the nature and extent of lung alterations in living pigs, a computed tomographic scoring system for quantifying gross pathological findings was developed. In this study, five healthy pigs served as control animals while 24 pigs were infected with App, the causative agent of pleuropneumonia in pigs, in an established model for respiratory tract disease.ResultsComputed tomographic (CT) findings during the course of App challenge were verified by radiological imaging, clinical, serological, gross pathology and histological examinations. Findings from clinical examinations and both CT and radiological imaging, were recorded on day 7 and day 21 after challenge. Clinical signs after experimental App challenge were indicative of acute to chronic disease. Lung CT findings of infected pigs comprised ground-glass opacities and consolidation. On day 7 and 21 the clinical scores significantly correlated with the scores of both imaging techniques. At day 21, significant correlations were found between clinical scores, CT scores and lung lesion scores. In 19 out of 22 challenged pigs the determined disease grades (not affected, slightly affected, moderately affected, severely affected) from CT and gross pathological examination were in accordance. Disease classification by radiography and gross pathology agreed in 11 out of 24 pigs.ConclusionsHigh-resolution, high-contrast CT examination with no overlapping of organs is superior to radiography in the assessment of pneumonic lung lesions after App challenge. The new CT scoring system allows for quantification of gross pathological lung alterations in living pigs. However, computed tomographic findings are not informative of the etiology of respiratory disease.

Infrared Thermography of the Pig Thorax: An Assessment of Selected Regions of Interest by Computed Tomographical and Anatomical Parameters

“…In this study, the high respiratory health status of pigs was important to establish preliminary reference values for difference thorax temperatures in healthy pigs. Respiratory health was confirmed by different examination methods, because a clinical examination alone is insufficient to draw conclusions about gross pathological changes (Straw et al., ; Brauer et al., ).…”

“…For detection of respiratory disease in living pigs CT examination can serve as a diagnostic gold standard (Brauer et al., ).…”

“…The used CT equipment was not appropriate to detect these interstitial tissue alterations, due to slices as narrow as 1 mm and a longer examination time being necessary (Brauer et al., ). CT Scores reflected mild lung tissue changes in several pigs.…”

“…Imaging procedures like computed tomography (CT) or digital radiography are of high sensitivity but are suitable for working practice. Neither CT nor radiography have been established as routine diagnostic methods in livestock medicine due to being time‐consuming and both cost‐ and personnel‐intensive (Brauer et al., , ).…”

Uterustumore bei älteren Miniaturschweinen – Diagnostik und Therapie

“…Je nach Lage des Tumors kann eine transabdominale oder eine transrektale sonographische Untersuchung aussagekräftigere Ergebnisse liefern, weshalb nach Möglichkeit beide Techniken kombiniert werden sollten. Neben der sonographischen und der röntgenologischen Untersuchung, deren Aussagekraft jedoch oftmals durch einen adipösen Ernährungszustand älterer Minipigs eingeschränkt ist, lässt sich, sofern verfügbar, auch die computertomographische Untersuchung (CT) bei der Diagnostik von Erkrankungen des Schweines, insbesondere bei Miniaturschweinen, einsetzen (6,7,12). Bei Vorliegen einer neoplastischen Erkrankung kann sie zusätzliche aussagekräftige Befunde liefern oder zumindest die Befunde der sonographischen Untersuchung bestätigen.…”