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.