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Toxoplasmosis (Toxoplasma)

(514) This is caused by the protozoa Toxoplasma gondii which affects animals and people. The life cycle is indirect. Cats are primary hosts and the only one that sheds infective oocysts in their faeces. Pigs may become infected by ingesting feed or water contaminated with cat faeces, by cannibalism of other infected dead pigs, by ear and tail biting or by eating infected rodents or other uncooked meat. Feed back of placenta is contraindicated. In the pig the organisms form cysts in muscles and other organs where they remain viable for long periods of time. These can develop then into the mature parasites when eaten. Pork therefore is a source of human infection.

Clinical signs

Clinical disease in the pig is uncommon. There are usually few signs or none at all. If infection occurs in the first 6-8 weeks of pregnancy the organism may cross the placenta and abortion may result but if it is later on piglets may die and become mummified. Occasionally increased stillbirths or premature piglets with tremor and coughing may occur. Piglets may also be born weak and lethargic. Diarrhoea may be seen.


The presence of the parasite rarely results in clinical disease. In cases of abortion foetal fluids from aborted piglets can be tested for the presence of antibodies. Serology can also be carried out on blood samples from pigs.


  • Sulphonamides and trimethoprim are effective by in-feed medication but treatment is rarely indicated.
Management control and prevention
  • Keep cats out of piggeries.
  • Keep cats out of feed and grain stores.
  • Control rodents.
  • Reduce and prevent cannibalism.

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