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Vetdle Archive

Archive Case #217: Bovine Malignant Catarrhal Fever

Cattle veterinary case - Hard - October 6, 2026

Clinical Clues

  1. At morning milking, Fern, an adult dairy cow, stays behind with a high fever and refuses her feed.
  2. Within a day, both eyes become painful and watery; thick discharge collects around her nostrils.
  3. Examination finds oral erosions and enlarged lymph nodes, alongside the eye and nasal lesions.
  4. The corneal cloudiness is spreading inward from the edges; sheep graze beside the cattle paddock.
  5. After she deteriorates and is euthanased, histology shows widespread vasculitis, including damaged small arteries.
  6. PCR on affected tissue detects ovine herpesvirus-2; together with the lesions, this confirms sheep-associated malignant catarrhal fever.

Diagnosis

Bovine Malignant Catarrhal Fever

Bovine Malignant Catarrhal Fever fits the ocular and mucosal disease, vasculitis and OvHV-2 result. IBR and BVD can cause overlapping signs; sheep contact alone would not establish the diagnosis. Remember: Cloudy corneas plus oral erosions suggest a systemic problem; laboratory evidence helps separate the lookalikes.

Learning review

Review the case evidence

Use the paired clues to explain how the evidence in this cattle case supports the provided diagnosis, Bovine Malignant Catarrhal Fever, then compare your reasoning with the case explanation.

Evidence checkpoints

Clues 1-2

  1. Clue 1: At morning milking, Fern, an adult dairy cow, stays behind with a high fever and refuses her feed.
  2. Clue 2: Within a day, both eyes become painful and watery; thick discharge collects around her nostrils.

Clues 3-4

  1. Clue 3: Examination finds oral erosions and enlarged lymph nodes, alongside the eye and nasal lesions.
  2. Clue 4: The corneal cloudiness is spreading inward from the edges; sheep graze beside the cattle paddock.

Clues 5-6

  1. Clue 5: After she deteriorates and is euthanased, histology shows widespread vasculitis, including damaged small arteries.
  2. Clue 6: PCR on affected tissue detects ovine herpesvirus-2; together with the lesions, this confirms sheep-associated malignant catarrhal fever.

Self-review prompts

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

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.