270 ESVP/ECVP Proceedings 2009 141:4, 2009

3COMPARISON OF THE PATHOLOGY OBSERVED IN LAMBSAND ADULT SHEEP EXPERIMENTALLY INFECTED WITH

MYCOBACTERIUM AVIUM SUBSP. PARATUBERCULOSISL. Delgado, M. Munoz, C. Garcıa-Pariente, M. Fuertes,

J. Benavides, J. Gonzalez, M. Ferreras, V. Perez andJ.F. Garcıa Marın

IGM-CSIC-ULE, Department of Animal Health, University of Leon, SpainIntroduction: The objective of this study was to evaluate the suscep-tibility of adult sheep to Mycobacterium avium subsp. paratuberculosis(Map) infection using different doses of Map.Materials and Methods: 24 lambs and 22 adult sheep were orallyinfected with two doses of Map (1010 and 103 CFU). Fourteen ani-mals remained as uninfected controls. The animals were necropsiedat 120 and 210 days post-infection. Numbers of granulomas werecounted and the severity of lesions was evaluated in samples of intes-tine and associated lymphoid tissue. Peripheral cellular immune re-sponse was assessed fortnightly.Results: No gross lesions were observed in any of the animals. Mi-croscopical lesions of paratuberculosis were detected only in thehigh dose-infected groups. Adult sheep showed small, demarcated fo-cal granulomas restricted to areas of lymphoid tissue. Lesions werelarger, more numerous and extended to the lamina propria in thelambs. The peripheral IFN-g response appeared earlier in the adultsheep than in the lambs.Conclusions: These results indicate the possibility of infection anddevelopment of characteristic lesions of paratuberculosis in adultsheep. Adult sheep seem better able to control the progression ofthe disease than lambs.

4PATHOGENESIS OF CHRONIC GASTRITIS IN AN ANIMAL

MODEL OF HELICOBACTER INFECTIONB. Flahou, S. Kumar, K. Van Deun, M. Vermoote, K. Chiers,

F. Pasmans, F. Haesebrouck and R. DucatelleFaculty of Veterinary Medicine, Ghent University, Belgium

Introduction: The role of Helicobacter spp. other than H. pylori in thedevelopment of gastric pathology in domestic animals is unclear. Re-cently, we isolated and characterized Helicobacter suis from the gastricmucosa of pigs.Materials and Methods: Mongolian gerbils were experimentallyinfected with the newly described species H. suis. The developmentof gastric pathology was studied microscopically at different time in-tervals after infection.Results: From 3 weeks after infection onwards, bacterial coloniza-tion of the antrum was associated with gradually increasing infiltra-tions of T and B lymphocytes in the propria mucosae, extendinginto the submucosa and the tunica muscularis at later stages. The ger-minal centres of the lymphoid follicle-like structures were expanded.Simultaneously, there was a mild loss of parietal cells at the transitionzone between fundus and antrum and an expansion of the dividingepithelial cell population. Ultrastructurally, the helically shaped bac-teria were found in close association with parietal cells and in debris ofnecrotic parietal cells.Conclusions: H. suis induces necrosis of parietal cells. We previouslyfound a similar phenomenon with Helicobacter felis. This has promptedongoing in-vitro studies of necrosis-inducing virulence factors.

5A COMPARISON OF STUDENT LEARNING USING

MICROSCOPES AND GLASS SLIDES OR DIGITIZEDIMAGES

P.J. Brown*, D. Fews y and N.J. Belly

*University of Nottingham, School of Veterinary Medicine and Science andyUniversity of Bristol School of Clinical Veterinary Science, UK

Introduction: Histopathology has traditionally been taught usingmicroscopes and histology slides, but the use of computers to view dig-itized images is becoming more common. The student experience ofusing both methods was assessed both objectively and subjectively.Materials and Methods: Students, at either Bristol, where histopa-thology has traditionally been taught using glass slides, or at Notting-ham, that makes use of digitized images (Digital Slidebox[�Slidepath, Dublin]) completed a simple formative test before andafter taking part in a practical class using either microscopes and his-tology slides or digitized images of the same slides.Results: In general, the performance of the students in the tests im-proved after participation in the practical classes; there was little dif-ference between students using glass slides or Digital Slidebox. Use ofDigital Slidebox improved performance in questions that requiredmore depth of knowledge beyond simple recognition of tissues or his-topathological changes; use of microscopes improved performance insome questions relating to tissue recognition. A subjective assessmentshowed no consistent student preference for digitized images or micro-scopes; the importance of the teacher/instructor during practical clas-ses was emphasized.Conclusions: Digitized images are useful in teaching veterinary his-topathology, but they are not more effective than teaching using mi-croscopes and histology slides.