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Vetdle Archive

Archive Case #87: Ovine Listeriosis

Sheep veterinary case - Hard - May 29, 2026

Clinical Clues

  1. A sheep develops depression, unilateral facial droop, and progressive circling behaviour.
  2. The flock has recently been fed poorly preserved silage.
  3. Examination reveals a head tilt and reduced menace response on one side.
  4. The ewe tends to lean and circle in one direction.
  5. The pattern localises to the brainstem rather than the spinal cord.
  6. A bacterial meningoencephalitis associated with spoiled silage commonly causes circling disease in sheep.

Diagnosis

Ovine Listeriosis

This case is most consistent with Ovine Listeriosis because the sheep has asymmetric cranial nerve deficits and circling behaviour after silage exposure. The most important clues are the brainstem localisation and feeding history, which make a simple vestibular ear disease less likely.

Learning review

Review the case evidence

Use the paired clues to explain how the evidence in this sheep case supports the provided diagnosis, Ovine Listeriosis, then compare your reasoning with the case explanation.

Evidence checkpoints

Clues 1-2

  1. Clue 1: A sheep develops depression, unilateral facial droop, and progressive circling behaviour.
  2. Clue 2: The flock has recently been fed poorly preserved silage.

Clues 3-4

  1. Clue 3: Examination reveals a head tilt and reduced menace response on one side.
  2. Clue 4: The ewe tends to lean and circle in one direction.

Clues 5-6

  1. Clue 5: The pattern localises to the brainstem rather than the spinal cord.
  2. Clue 6: A bacterial meningoencephalitis associated with spoiled silage commonly causes circling disease in sheep.

Self-review prompts

  1. After clues 1-2, what evidence from this sheep case shaped your initial interpretation?
  2. When you compare clues 3-4 with clues 1-2, what changed in your reasoning about Ovine Listeriosis?
  3. How do clues 5-6 align with the case explanation for Ovine Listeriosis?

Educational Use

Vetdle archive cases are educational veterinary games for diagnostic reasoning practice. They do not provide veterinary advice, diagnosis, treatment, or professional medical guidance.