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Vetdle Archive

Archive Case #221: Swine Ascariasis

Pig veterinary case - Easy - October 10, 2026

Clinical Clues

  1. At a grower-unit review, pigs in one group are gaining weight poorly and several have developed a cough.
  2. The coughing is accompanied by rough coats and uneven growth, so dust alone does not explain the whole picture.
  3. The group has remained on heavily contaminated pens through repeated batches, with an inconsistent parasite-control history.
  4. Livers from recently slaughtered herd mates contain scattered pale fibrotic lesions described as milk spots.
  5. An affected pig examined postmortem has large roundworms within the small intestine, providing evidence beyond the liver lesions.
  6. The worms are identified as Ascaris suum, confirming ascariasis; repeated exposure explains intestinal worms alongside recent larval-migration lesions.

Diagnosis

Swine Ascariasis

Swine Ascariasis fits the identified worms and compatible herd findings. Milk spots alone are not specific, and coughing may have additional causes. Larval migration can precede detectable faecal eggs. Remember: A negative faecal egg test does not exclude an early migrating infection; interpret it alongside the parasite's life cycle.

Learning review

Review the case evidence

Use the paired clues to explain how the evidence in this pig case supports the provided diagnosis, Swine Ascariasis, then compare your reasoning with the case explanation.

Evidence checkpoints

Clues 1-2

  1. Clue 1: At a grower-unit review, pigs in one group are gaining weight poorly and several have developed a cough.
  2. Clue 2: The coughing is accompanied by rough coats and uneven growth, so dust alone does not explain the whole picture.

Clues 3-4

  1. Clue 3: The group has remained on heavily contaminated pens through repeated batches, with an inconsistent parasite-control history.
  2. Clue 4: Livers from recently slaughtered herd mates contain scattered pale fibrotic lesions described as milk spots.

Clues 5-6

  1. Clue 5: An affected pig examined postmortem has large roundworms within the small intestine, providing evidence beyond the liver lesions.
  2. Clue 6: The worms are identified as Ascaris suum, confirming ascariasis; repeated exposure explains intestinal worms alongside recent larval-migration lesions.

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 Swine Ascariasis?
  3. How do clues 5-6 align with the case explanation for Swine Ascariasis?

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.