Bovine and Ovine Eosinophilic Myositis

• Unknown aetiology
• Major cell involved is eosinphil
• Usually noticed at slaughter - green muscle discoloration
• May be caused by degenteration of Sarcocystis spp.
• Grossly:
  • Green discolored areas, well demarcated
  • Mostly in muscles of back and thighs
• Histologically:
  • Massive eosinophil infiltration
  • Muscle fibres may degenerate
  • In old lesions - endimysial fibrosis, myofibre atrophy, some regeneration, lymphocytes, plasma cells, macrophages and few eosinophils
  • Capsule may form