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Internal Parasites (Worms etc.)

In the sow the important parasites are the large white worms ascarids (Ascaris suum), red stomach worms (Hyostrongylus rubidus) and whip worms (Trichuris suis).

The sow becomes the source of potential infection to piglets. The threadworm (Strongyloides ransomi) is important in the piglet. The life cycles of all are direct from eggs in faeces to adult in the intestine.

Internal parasites are an uncommon problem in the weaned, growing and finisher pig unless they are housed in continuously occupied straw based or bare concrete pens in which case ascarids may become a problem.



May include the following:

  • Coughing.
  • Loss of body condition.
  • Hairy pigs.
  • Vomiting.
  • Blood in faeces but rarely.
  • Anaemia.
  • Diarrhoea - sloppy.
Piglets (Thread Worm)
  • Coughing.
  • Stiffness.
  • Pain.
  • Vomiting.
  • Bloody diarrhoea.
  • Some mortality.
Weaners & Growers
  • Coccidiosis could cause diarrhoea within 7 to 10 days of entry to continually used pens.
  • Strongyle infections (poor growth and sloppy faeces) within 3 to 4 weeks
  • Coughing.
  • Blood in faeces.
  • Pneumonia / Heavy breathing.
  • Pale pigs.

Causes / Contributing factors

  • Management systems that allow regular access to faeces.
  • Faeces allowed to accumulate for more than 3 - 4 days (allows eggs to become infective).
  • Moist wet areas encourage survival of eggs.
  • No all-in, all-out management.
  • Permanently populated yards or paddocks outdoors.
  • Failure to monitor faeces for egg output.
  • Failure to carry out routine treatments when indicated.
  • Continuously used pens predispose.
  • Wet dirty floors.
  • Carrier pigs.


This is based on symptoms and identification of the parasites. Laboratory examination of faeces for worm eggs.

Photo's of the various worms

Large white worm Eggs
(Ascaris suum)

Large white worm
(Ascaris suum)

Threadworm Eggs
(Strongyloides ransomi)

(Strongyloides ransomi)

Whipworm Eggs
(Trichuris suis)

(Encysted larvae of trichinella spiralis)

Trichuris suis
Encysted larvae of trichinella spiralis

Further Reading

Click on the links below to find out more about this disease, including treatment, management control and prevention information. The top link is the main article on this disease.