Pathological features of systemic necrotizing vasculitis (polyarteritis nodosa) in sheep
M C Ferreras1, J Benavides, M Fuertes
1Departamento de Sanidad Animal (Anatomía Patológica), Instituto de Ganadería de Montaña (CSIC-ULE), Facultad de Veterinaria, Universidad de León, Campus de Vegazana, s/n, 24071 León, Spain. mcfere@unileon.es
Journal of Comparative Pathology
|November 6, 2012
Summary
Polyarteritis nodosa (PAN), a rare vasculitis, was identified in four sheep, causing severe vascular damage and affecting organs like kidneys and skin. The disease appears to involve a cell-mediated immune response, not immune complexes.
Area of Science:
- Veterinary Pathology
- Immunology
- Sheep Medicine
Background:
- Polyarteritis nodosa (PAN) is a systemic vasculitis affecting small- and medium-sized arteries.
- PAN's etiology is unknown, and it typically spares pulmonary arteries.
- This study focuses on PAN in sheep, a less commonly reported host.
Purpose of the Study:
- To describe the pathological findings of polyarteritis nodosa in four sheep.
- To investigate the potential immune mechanisms involved in ovine PAN.
- To highlight clinical and gross findings associated with this vasculitis in sheep.
Main Methods:
- Case description of four sheep diagnosed with PAN.
- Gross necropsy and detailed histopathological examination of affected tissues.
- Immunohistochemical analysis to identify inflammatory cell types and immune deposition.
Main Results:
- Clinical signs included locomotor disturbances.
- Gross findings revealed nodular vascular thickening, thrombosis, and aneurysms.
- Histopathology confirmed segmental fibrinoid necrosis, transmural inflammation, and arterial occlusion, particularly in kidneys, with no immune complex deposition. Inflammatory infiltrates comprised T lymphocytes and macrophages.
Conclusions:
- Ovine polyarteritis nodosa presents with distinct vascular lesions and can cause significant clinical signs.
- The pathogenesis may involve a cell-mediated immune response, as evidenced by T lymphocyte and macrophage infiltration.
- This study contributes to understanding PAN in livestock and suggests a non-immune complex-mediated mechanism.
