Mucormycosis

Granulomatous inflammation

• Mucor, a fungi, invades the rumen wall, e.g. after damage caused by rumenal acidosis.
• Produces chronic ongoing granulomatous rumenitis.
• Difficult to diagnose in life.
• May produce pain and poor growth
• Infective process may penetrate wall and produce peritonitis.

Pathology

Gross

• Thickening and ulceration of mucosal surface of rumen.
  • Feels like thick leather.
• Rumen wall becomes fibrosed.

Histological

• Classical granulomatous inflammation
  • May have giant cells in addition to sheets of macrophages.
• Can visualise fungal hyphae in tissue using special stains (PAS),
  • Often grow along blood vessels.
    • May cause thrombosis of small blood vessels, leading to further necrosis (infarction) of rumen wall.

Caused by a fungus of the Mucoracae family. Causes a granulomatous rumenitis in cattle with sheets of macrophages and giant cells vvisble on histopathology. Grossly the rumen is thickened and fibrosed and may become ulcerated.

The infection may penetrate the rumen wall leading to a peritonitis. It may also enter blood vessels leading to a thrombosis, infarction and further damage to the vessel wall.

Fungal hyphae are identified histologically with the stain PAS (Periodic acid Schiff) where they stain as purple/red rod like structures.