48 ESVP/ECVP Proceedings 2011 146:1, 2012

PATHOGENESIS OF CLOSTRIDIUM PERFRINGENS TYPE CENTERITIS: THE PORCINE CASE

H. Posthaus*, V. Schumacher*, A. Martel y, F. Pasmans y,L. Timbermont y, R. Ducatelle y and F. Van Immerseely*Institute of Animal Pathology, University of Berne, Switzerland and

yDepartment of Pathology, Bacteriology and Avian Medicine,Ghent University, Belgium

Introduction: Necrotizing enteritis caused by C. perfringens type C isa fatal disease of animals and man. C. perfringens beta toxin (CPBT) isthe essential virulence factor; however, its cellular and molecularmode of action is still unknown.Materials andMethods: The effects of purified CPBT, C. perfringenstype C culture supernatants and strains on porcine small intestinalmucosa were studied using different approaches in vitro and in vivo.Investigations included immunohistochemical and ultrastructuralstudies and cell biological and biochemical testing.Results: C. perfringens type C strains rapidly induced necrohaemor-rhagic lesions in ligated neonatal porcine small intestinal loops.CPBT was highly toxic to primary porcine endothelial cells, inducingrapid programmed necrosis in these cells. Moreover, it was able tobind to endothelial cells in small intestinal mucosal explants.However, porcine small intestinal epithelial cells were not affectedby the toxin. Nevertheless, culture supernatants were able to inducemorphological damage to intestinal epithelial cells.Conclusions: Endothelial cells are the primary target of CPBT. Theepithelial damage, required for penetration of the toxin into the tissueis induced by additional virulence factors. Identification of such fac-tors will be important to understand the pathogenesis of C. perfringensenteric diseases.

WADDLIA, PARACHLAMYDIA AND CHLAMYDIACEAEIN BOVINE ABORTION

S. Blumer*, G. Greub y, A. Waldvogel z, M. H€assig x,R. Thoma{, A. Tschuor x, A. Pospischil* and N. Borel**Institute for Veterinary Pathology, Zurich, yInstitute of Microbiology,

Lausanne, zInstitute Galli-Valerio, Lausanne, xDepartment for Farm Animals,Zurich and {Cantonal Laboratory of Veterinary Bacteriology, Chur,

SwitzerlandIntroduction: The aetiology remains unknown in many cases of bo-vine abortion in Switzerland and worldwide. Bacteria of the orderChlamydiales are known abortive agents, therefore cases of bovineabortion from three representative regions of Switzerland were inves-tigated in this study.Materials and Methods: Placenta samples (n5 343) were testedfor Chlamydiaceae and for the Chlamydia-like organisms Waddlia andParachlamydia by different PCR methods, immunohistochemistry(IHC) and serology for Chlamydia (C.) abortus.Results: In 67.3% of the 343 cases a necrotizing and/or purulent pla-centitis was found histologically. By real-time PCR, 0.9% (3/343) ofthe cases were positive for Waddlia, 13.4% (46/343) were positive forParachlamydia and 14.6% (50/343) were positive or questionably pos-itive for Chlamydiaceae. Of these samples, confirmation by IHC waspossible in 2/3 cases for Waddlia, 25/46 for Parachlamydia and 4/50for Chlamydiaceae. Of the 50 cases positive or questionably positivefor Chlamydiaceae, species identification by ArrayTube Microarray or16S rRNA PCR resulted in 41 cases positive for C. abortus, whilethe presence of C. suis was confirmed in four and C. pecorum in onecase.Conclusions: This study brought evidence of the importance of dif-ferent members of Chlamydiales in different regions of Switzerland,although Waddlia does not occur in high prevalence.

HISTOLOGICAL FINDINGS IN BOVINE SKIN AFTERNATURAL INFECTION WITH BESNOITIA BESNOITI

M. Langenmayer*, M. Majzoub*, N. Gollnick y, J. Scharr y,G. Schares z and W. Hermanns*

*Institute of Veterinary Pathology, yClinic for Ruminants with Ambulatory andHerd Health Services, Ludwig-Maximilians-Universit€at M€unchen and

zFriedrich-Loeffler-Institut, Federal Research Institute for Animal Health,

Wusterhausen, GermanyIntroduction: Besnoitia besnoiti, a cyst-forming coccidian, is the causeof bovine besnoitiosis. Little is known about the life cycle and trans-mission of the parasite. During an infection trial, clinical and patho-logical changes after natural infection with B. besnoiti were monitored.Materials and Methods: Five Simmental heifers and one Simmen-tal bull were held on pasture with three Limousin cows infectedchronically with besnoitiosis. All animals were examined daily andblood and skin samples were taken at regular intervals. During thetrial, two additional Limousin cows suspected to be suffering fromacute besnoitiosis were added to the group of trial animals.Histological sections were stained with HE and Giemsa. Immunohis-tochemistry (IHC) for parasite detection was performed using a poly-clonal rabbit antiserum.Results: Infection with B. besnoiti was confirmed by serology andPCR in the two Limousin cows added during the trial and in threeof the Simmental heifers. Parasites were detected in routine stainsand by IHC. Cyst formation from young to mature stages and hostimmune response to the parasite were monitored.Conclusions: B. besnoiti can be transmitted naturally in our climaticregion. Infection can be confirmed by PCR, serology or histology.

HISTOPATHOLOGICAL FINDINGS IN ANIMALS AFFECTEDBY BOVINE BESNOITIOSIS, WITH SPECIAL FOCUS ON

MALE GENITAL ORGANSJ. L�opez*, L. Grau-Roma*, J. Mart�ınez*, N. Maj�o*,y,

A. Marco*, A. Castillo z and M. Domingo*,y*Departament de Sanitat i Anatomia Animals, Universitat Aut�onoma deBarcelona (UAB), yCentre de Recerca en Sanitat Animal (CReSA),

UAB-IRTA, Barcelona and zAnimal Pathology Department, Faculty ofVeterinary Sciences, University of Zaragoza, Spain

Introduction: Bovine besnoitiosis, caused by Besnoitia besnoiti, is anemerging disease in the EU. Although some work has mentionedthe presence of orchitis and sterility in bulls suffering from besnoitio-sis, there are no studies describing the testicular lesions.Materials and Methods: Seventeen animals from the same herd(10 cows and seven bulls) with skin lesions (scleroderma, hyperkera-tosis and multifocal alopecia) were slaughtered for sanitary reasons.Several tissues, including skin, mucous membranes and sexual organswere studied histopathologically, using haematoxylin and eosin andMasson’s trichrome stains, and by immunohistochemistry (IHC) forexpression of factor VIII and vimentin.Results: Multifocal, chronic, granulomatous and eosinophilic inflam-mation, mainly associated with intracellular protozoan cysts, was ob-served in several tissues. Skin, nasal and oral mucosa, tongue, eye,eyelid, conjunctiva andmale genital organs were the most frequently af-fected. In the male genital organs, the lesions were observed within theepididymis and/or pampiniform plexus of three bulls, but not in the tes-ticular parenchyma. One of the bulls had multifocal and extensive areasof necrosis and mineralization within testicular parenchyma, togetherwith lack of spermatozoa in one epididymis and few in the other. Often,cysts were associated with vascular structures. IHC showed that the cellscontaining the cysts were negative for factorVIII andpositive for vimen-tin.Masson’s trichrome stainmarked the cells containing the cysts in red.Conclusions: The results suggest that cysts of B. besnoiti may havea tropism for vascular walls of the pampiniform plexus and epididy-mis. Histochemistry and IHC indicated that cysts are located withinthe muscular cells of the tunica media of the vascular wall, causingcompression and vascular stenosis. This situation may cause subse-quent ischaemia, testicular necrosis, azospermia and infertility.