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Vetdle Archive

Archive Case #209: Porcine Circovirus 2 Systemic Disease

Pig veterinary case - Hard - September 28, 2026

Clinical Clues

  1. Several ten-week-old pigs in pen four are becoming noticeably smaller than their littermates despite access to feed.
  2. They develop rough coats and progressive wasting; some also have loose faeces or laboured breathing.
  3. Multiple superficial lymph nodes are enlarged, and losses increase over the following weeks.
  4. Necropsy of an affected pig reveals widespread lymph-node enlargement and interstitial pneumonia.
  5. Histology shows pronounced lymphoid depletion with histiocytic and granulomatous replacement in several lymph nodes.
  6. Immunohistochemistry demonstrates abundant PCV2 antigen within those lesions, supporting PCV2 systemic disease in this clinically affected pig.

Diagnosis

Porcine Circovirus 2 Systemic Disease

Porcine Circovirus 2 Systemic Disease is supported by wasting, characteristic lymphoid damage and abundant PCV2 within those lesions. This identifies a specific syndrome within the broader circovirus-associated disease group; a positive PCR alone would not distinguish it from infection without disease. Remember: Match a positive pathogen test to the illness and tissue lesions, not just the organism's name.

Learning review

Review the case evidence

Use the paired clues to explain how the evidence in this pig case supports the provided diagnosis, Porcine Circovirus 2 Systemic Disease, then compare your reasoning with the case explanation.

Evidence checkpoints

Clues 1-2

  1. Clue 1: Several ten-week-old pigs in pen four are becoming noticeably smaller than their littermates despite access to feed.
  2. Clue 2: They develop rough coats and progressive wasting; some also have loose faeces or laboured breathing.

Clues 3-4

  1. Clue 3: Multiple superficial lymph nodes are enlarged, and losses increase over the following weeks.
  2. Clue 4: Necropsy of an affected pig reveals widespread lymph-node enlargement and interstitial pneumonia.

Clues 5-6

  1. Clue 5: Histology shows pronounced lymphoid depletion with histiocytic and granulomatous replacement in several lymph nodes.
  2. Clue 6: Immunohistochemistry demonstrates abundant PCV2 antigen within those lesions, supporting PCV2 systemic disease in this clinically affected pig.

Self-review prompts

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

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.