Bacillus anthracis as a cause of bovine abortion - a necropsy case requiring special biosafety measures.

INTRODUCTION: In spring 2017, the first case of bovine anthrax in 20 years in Switzerland occurred in the canton of Jura. Carcasses of anthrax-deceased animals should not be opened due to the formation of highly resistant spores bearing the risk of environmental contamination and aerosolization. Nevertheless, in the course of this local outbreak, one sick cow from the affected farm, whose blood repeatedly tested negative for Bacillus anthracis, was necropsied after euthanasia under special biosafety precautions at the Institute of Animal Pathology, Vetsuisse-Faculty Bern. Necropsy revealed ventral edema, fetal death, necro-hemorrhagic placentitis and necrotizing iliac lymphadenitis. Bacillus anthracis was isolated only from placenta and altered lymph node. The biosafety measures taken during and after necropsy prevented a contamination of the necropsy environment, which was proven with bacteriological swabs. This case shows that anthrax may elicit unspecific symptoms mimicking other diseases, and veterinarians must be aware of these non-septicemic cases.

[Paraparesis in a dwarf goat: clarification by means of magnetic resonance imaging]. / Paraparese bei einer Zwergziege: Abklärung mittels Magnetresonanztomographie.

A 4-year old pygmy goat with chronic paraparesis of the hindlimbs was referred to the Ruminant Clinic of the University of Berne. The causative lesion was localized to the thoracolumbar spinal cord after a thorough clinical examination. Because a radiographic examination of the spine had not been diagnostic, magnetic resonance imaging (MRI) was performed. A mass compressing the spinal cord in the region of L2-L5 was detected. The goat was euthanized and autopsied, which allowed for the definitive diagnosis of lymphosarcoma. In addition to the changes in the lumbar area, further neoplastic masses were detected in the region of the thoracic vertebrae, near the thoracic aperture, on the lungs and on the pericardium. However, these processes had not yet caused clinical signs. MRI investigation allowed for the ante mortem diagnosis of an infiltrative mass in the spinal canal of this goat.

Thymoma-associated exfoliative dermatitis in cats.

Five cases of exfoliative dermatitis in cats were presented from 1996 to 2002 in which a feline thymoma was found by postmortem or postsurgical examination. Besides abundant exfoliation of keratin squames and layers, the histologic picture of the skin revealed a similar pattern of interface dermatitis with predominantly CD3+ lymphocytes and fewer mast cells and plasma cells. In the epidermal basal layer a hydropic degeneration of keratinocytes was present. In all cases an infundibular lymphocytic mural folliculitis and absence of or drastic decrease in the number of sebaceous glands occurred. In addition to the so far described cell-poor type, we also found examples of a cell-rich skin lesion. Together with the clinical observation of generalized exfoliative dermatitis, the histologic pattern of this dermatitis was suggestive of an underlying thymoma. The pathogenesis of this skin disease in association with thymic neoplasia remains obscure, and our results contradict the hypothesis of production of autoantibodies that cross-react with epithelial antigens. The morphology of the thymomas and CD3 expression of the thymocytes varied and did not seem to have an impact on the dermal lesions.

Inhibition of apoptosis by intracellular protozoan parasites.

Protozoan parasites which reside inside a host cell avoid direct destruction by the immune system of the host. The infected cell, however, still has the capacity to counteract the invasive pathogen by initiating its own death, a process which is called programmed cell death or apoptosis. Apoptotic cells are recognised and phagocytosed by macrophages and the parasite is potentially eliminated together with the infected cell. This potent defence mechanism of the host cell puts strong selective pressure on the parasites which have, in turn, evolved strategies to modulate the apoptotic program of the host cell to their favour. Within the last decade, the existence of cellular signalling pathways which inhibit the apoptotic machinery has been demonstrated. It is not surprising that intracellular pathogens subvert these pathways to ensure their own survival in the infected cell. Molecular mechanisms which interfere with apoptotic pathways have been studied extensively for viruses and parasitic bacteria, but protozoan parasites have come into focus only recently. Intracellular protozoan parasites which have been reported to inhibit the apoptotic program of the host cell, are Toxoplasma gondii, Trypanosoma cruzi, Leishmania sp., Theileria sp., Cryptosporidium parvum, and the microsporidian Nosema algerae. Although these parasites differ in their mechanism of host cell entry and in their final intracellular localisation, they might activate similar pathways in their host cells to inhibit apoptosis. In this respect, two families of molecules, which are known for their capacity to interrupt the apoptotic program, are currently discussed in the literature. First, the expression of heat shock proteins is often induced upon parasite infection and can directly interfere with molecules of the cellular death machinery. Secondly, a more indirect effect is attributed to the parasite-dependent activation of NF-kappaB, a transcription factor that regulates the transcription of anti-apoptotic molecules.